Patent ID: 12220534

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

A breathing assistance apparatus10for delivering a flow of gas (which may contain one or more gases) to a patient is shown inFIG.1. The apparatus10could, for example, be a CPAP apparatus or a high flow apparatus. An exemplary CPAP apparatus is described in WO 2011/056080. The contents of that specification are incorporated herein in their entirety by way of reference.

A CPAP apparatus is a gases supply and optionally gases humidification apparatus. The apparatus is operable to provide respiratory assistance to patients or users who require a supply of gas (humidified or otherwise) at positive pressure for the treatment of diseases such as Obstructive Sleep Apnea (OSA), snoring, or Chronic Obstructive Pulmonary Disease (COPD) and the like. A CPAP apparatus would typically include a humidifier liquid chamber, so as to form a combined assisted breathing unit and humidifier.

CPAP apparatuses, when used with a humidifier, typically have a structure where gases at a required pressure are delivered from an assisted breathing unit or blower unit to a liquid chamber downstream from the blower. As the gases pass through the liquid chamber, they become saturated with liquid vapour (e.g. water vapour). A flexible tubular gases conduit delivers the gases to a user or patient downstream from the humidifier chamber.

A high flow apparatus may be used to deliver a high gas flow or high flow therapy to a patient to assist with breathing and/or treat breathing disorders including chronic obstructive pulmonary disease (COPD). A high flow apparatus includes a gases supply and typically includes a humidification apparatus.

The breathing assistance apparatuses typically have one or more accessories such as a breathing conduit and a patient interface such as a cannula or mask for delivering gases to a patient. The conduit enables gases to be delivered from the housing of the breathing assistance apparatus to the patient. For example, the apparatus may be placed on a floor or other support surface, and the patient may be in a bed. The breathing assistance apparatus may have a recess for receipt of a humidifier liquid chamber. The liquid chamber will receive liquid from, for example, a flexible liquid bag that delivers liquid to a humidifier liquid chamber via one or more tubes. Alternatively, the liquid chamber can be removed and refilled as required. The recess will contain a heater plate to heat the liquid chamber, to humidify gases passing through the liquid chamber. The humidified gases are then delivered to the patient.

In general terms, the apparatus10comprises a main housing100that contains a flow generator11in the form of a motor/impeller arrangement, a humidifier12, a controller13, and a user I/O interface14(comprising, for example, a display and input device(s) such as button(s), a touch screen, or the like). The controller13is configured or programmed to control the components of the apparatus, including: operating the flow generator11to create a flow of gas (gas flow) for delivery to a patient, operating the humidifier12to humidify and/or heat the generated gas flow, receive user input from the user interface14for reconfiguration and/or user-defined operation of the apparatus10, and output information (for example on the display) to the user. The user could be a patient, healthcare professional, or anyone else interested in using the apparatus.

A patient breathing conduit16is connected to a gas flow output or patient outlet port30in the housing100of the breathing assistance apparatus10, and is connected to a patient interface17such as a nasal cannula with a manifold19and nasal prongs18. Additionally, or alternatively, the patient breathing conduit16could be connected to a face mask. Additionally, or alternatively, the patient breathing conduit could be connected to a nasal pillows mask, and/or a nasal mask, and/or a tracheostomy interface, or any other suitable type of patient interface. The gas flow, which may be humidified, that is generated by the breathing assistance apparatus10is delivered to the patient via the patient breathing conduit16through the patient interface17. The patient breathing conduit16can have a heater wire16ato heat gas flow passing through to the patient. The heater wire16ais under the control of the controller13. The patient breathing conduit16and/or patient interface17can be considered part of the breathing assistance apparatus10, or alternatively peripheral to it. The breathing assistance apparatus10, breathing conduit16, and patient interface17may together form a breathing assistance system or, in some configurations, a flow therapy system.

General operation of an exemplary breathing assistance apparatus10will be known to those skilled in the art, and need not be described in detail here. However, in general terms, the controller13controls the flow generator11to generate a gas flow of the desired flow rate, controls one or more valves to control the mix of air and oxygen or other alternative gas, and/or controls the humidifier12to humidify the gas flow and/or heat the gas flow to an appropriate level. The gas flow is directed out through the patient breathing conduit16and patient interface17to the patient. The controller13can also control a heating element in the humidifier12and/or the heating element16ain the patient breathing conduit16to humidify and/or heat the gas to a desired temperature that achieves a desired level of therapy and/or comfort for the patient. The controller13can be programmed with, or can determine, a suitable target temperature of the gas flow.

Operation sensors3a,3b,3c,20, and25, such as flow, temperature, humidity, and/or pressure sensors, can be placed in various locations in the breathing assistance apparatus10and/or the patient breathing conduit16and/or patient interface17. Output from the sensors can be received by the controller13, to assist it to operate the breathing assistance apparatus10in a manner that provides optimal therapy. In some configurations, providing optimal therapy includes meeting a patient's inspiratory flow. The apparatus10may have a transmitter and/or receiver15to enable the controller13to receive signals8from the sensors and/or to control the various components of the breathing assistance apparatus10, including but not limited to the flow generator11, humidifier12, and heater wire16a, or accessories or peripherals associated with the breathing assistance apparatus10. Additionally, or alternatively, the transmitter and/or receiver15may deliver data to a remote server or enable remote control of the apparatus10.

The breathing assistance apparatus10may be any suitable type of apparatus, but in some configurations may deliver a high gas flow or high flow therapy (of e.g. air, oxygen, other gas mixture, or some combination thereof) to a patient to assist with breathing and/or treat breathing disorders. In some configurations, the gas is or comprises oxygen. In some configurations, the gas comprises a blend of oxygen and ambient air. High flow therapy as discussed herein is intended to be given its typical ordinary meaning as understood by a person of skill in the art which generally refers to a respiratory assistance system delivering a targeted flow of humidified respiratory gases via an intentionally unsealed patient interface with flow rates generally intended to meet or exceed inspiratory flow of a patient. Typical patient interfaces include, but are not limited to, a nasal or tracheal patient interface. Typical flow rates for adults often range from, but are not limited to, about fifteen liters per minute (LPM) to about seventy liters per minute or greater. Typical flow rates for pediatric patients (such as neonates, infants and children) often range from, but are not limited to, about one liter per minute per kilogram of patient weight to about three liters per minute per kilogram of patient weight or greater. High flow therapy can also optionally include gas mixture compositions including supplemental oxygen and/or administration of therapeutic medicaments. High flow therapy is often referred to as nasal high flow (NHF), humidified high flow nasal cannula (HHFNC), high flow nasal oxygen (HFNO), high flow therapy (HFT), or tracheal high flow (THF), among other common names.

For example, in some configurations, for an adult patient ‘high flow therapy’ may refer to the delivery of gases to a patient at a flow rate of greater than or equal to about 10 liters per minute (10 LPM), such as between about 10 LPM and about 100 LPM, or between about 15 LPM and about 95 LPM, or between about 20 LPM and about 90 LPM, or between about 25 LPM and about 85 LPM, or between about 30 LPM and about 80 LPM, or between about 35 LPM and about 75 LPM, or between about 40 LPM and about 70 LPM, or between about 45 LPM and about 65 LPM, or between about 50 LPM and about 60 LPM. In some configurations, for a neonatal, infant, or child patient ‘high flow therapy’ may refer to the delivery of gases to a patient at a flow rate of greater than 1 LPM, such as between about 1 LPM and about 25 LPM, or between about 2 LPM and about 25 LPM, or between about 2 LPM and about 5 LPM, or between about 5 LPM and about 25 LPM, or between about 5 LPM and about 10 LPM, or between about 10 LPM and about 25 LPM, or between about 10 LPM and about 20 LPM, or between about 10 LPM and 15 LPM, or between about 20 LPM and 25 LPM. A high flow therapy apparatus with an adult patient, a neonatal, infant, or child patient, may, in some configurations, deliver gases to the patient at a flow rate of between about 1 LPM and about 100 LPM, or at a flow rate in any of the sub-ranges outlined above. Gases delivered may comprise a percentage of oxygen. In some configurations, the percentage of oxygen in the gases delivered may be between about 20% and about 100%, or between about 30% and about 100%, or between about 40% and about 100%, or between about 50% and about 100%, or between about 60% and about 100%, or between about 70% and about 100%, or between about 80% and about 100%, or between about 90% and about 100%, or about 100%, or 100%.

High flow therapy has been found effective in meeting or exceeding the patient's inspiratory flow, increasing oxygenation of the patient and/or reducing the work of breathing. Additionally, high flow therapy may generate a flushing effect in the nasopharynx such that the anatomical dead space of the upper airways is flushed by the high incoming gas flows. This creates a reservoir of fresh gas available for each and every breath, while minimising re-breathing of carbon dioxide, nitrogen, etc.

In one example for high flow therapy, an unsealed or non-sealing user interface, e.g. a nasal cannula, is used. For CPAP a sealed interface is typically used, e.g. a nasal mask, full face mask, or nasal pillows.

The patient interface17may be a non-sealing interface to prevent barotrauma (e.g. tissue damage to the lungs or other organs of the respiratory system due to difference in pressure relative to the atmosphere). The patient interface may be a nasal cannula with a manifold and nasal prongs, and/or a face mask, and/or a nasal pillows mask, and/or a nasal mask, and/or a tracheostomy interface, or any other suitable type of patient interface.

As described below, the breathing assistance apparatus10has various features to assist with the functioning, use, and/or configuration of the breathing assistance apparatus10.

As shown inFIGS.2to5, a first configuration breathing assistance apparatus10comprises a breathing assistance apparatus base unit50having a main housing100. The main housing100has a main housing upper chassis102and a main housing lower chassis104.

The main housing of the base unit50has a peripheral wall arrangement. The peripheral wall arrangement defines a recess108that provides a humidifier liquid chamber bay for receipt of a removable humidifier liquid chamber151. The removable liquid chamber151contains a suitable liquid such as water for humidifying gases that will be delivered to a patient.

The base unit50of the apparatus10may have a movable finger guard140that guards against a user touching a base flange155of the liquid chamber when the liquid chamber is in place in the recess108and when a barrier141aof the finger guard is in a covering position as shown in the figures. The barrier141ais movable between the covering position and a lowered access position in which the recess108is less covered or is uncovered by the barrier141a.

In the form shown, the main housing lower chassis104peripheral wall arrangement comprises a substantially vertical left side outer wall109that is oriented in a front-to-rear direction of the main housing100, a substantially vertical right side outer wall111, and a substantially vertical rear outer wall113(FIG.37) that extends between and connects the walls109,111. As shown inFIGS.36and37, a bottom wall115extends between and connects the lower ends of walls109,111,113, and forms a base of the apparatus and a substantially horizontal floor portion of the liquid chamber bay.

The floor portion of the recess108has a receptacle portion108ato receive a heater arrangement such as a heater plate140or other suitable heating element(s) for heating liquid in the liquid chamber151for use during a humidification process. The heater plate would typically have a shape that substantially corresponds to the shape of a base154of the liquid chamber151, such as a circular shape for example. The heater plate140is resiliently mounted; for example, on biasing device(s) such as spring(s). The resilient mounting enables the heater plate to move downwardly to accommodate the liquid chamber151in the recess108, while maintaining good contact between the heater plate140and the base of the liquid chamber once the liquid chamber is inserted in the recess108.

The main housing lower chassis104is attachable to the upper chassis102, either by suitable fasteners or integrated attachment features such as clips for example. When the main housing lower chassis104is attached to the main housing upper chassis102, the walls of the upper and lower chassis engage with each other.

The lower chassis104has a motor recess122(FIG.39) for receipt of a motor module which may be permanently inserted in the motor recess122or may be removable from the motor recess122. A recess opening is provided in the bottom wall115adjacent a rear edge thereof, for receipt of the removable motor module. A base123of the motor module covers the opening into the motor recess121. The motor module comprises a motor that forms a blower to cause gas flow, and may comprise one or more sensors to sense properties of the gas passing through the motor module. The motor module may comprise sensor(s) to sense parameters of gases flowing through the motor module.

The motor module and housing of the base unit50of the apparatus10are provided with suitable tubes and/or gas flow passages to deliver gases from one or more gases inlets of the base unit50of the apparatus, to a gas inlet port157of the liquid chamber151to humidify the gases. The gases are delivered from a gas outlet port159of the liquid chamber151to the patient outlet port30(via a humidified gas inlet port163) and thereby to the patient via the patient breathing conduit16and patient interface17.

The motor recess122comprises a recess opening in a bottom wall115of the housing. Alternatively, the recess opening could be in a different part of the housing, such as a side, front, or top of the housing.

The base unit50of the apparatus10may have a battery module125to provide power to the apparatus when there is a power outage or for portable use. The battery module comprises a battery cover126containing a battery. The battery of the battery module125may be replaceable.

In the form shown, the battery cover126of the battery module125is coupled to an exterior of the back wall113of the apparatus housing100. This provides a large surface area to cool the battery and reduces the amount of heat entering the apparatus from the battery. Additionally, this configuration reduces the influence of heat generated by components of the apparatus on the battery, particularly when the battery is being charged. In an alternative configuration, the battery may be internally mounted in the main housing.

The housing may be provided with a battery cover126(FIGS.48a,48b) to cover the battery once installed. Alternatively, the battery may mount directly to the housing100without a cover. The battery, and therefore the battery cover126, may be sized to not extend beyond the bottom wall115of the housing. Alternatively, the battery cover126may be longer and extend beyond the bottom wall115of the housing to accommodate a larger battery.

As shown inFIG.3, the base unit50of the apparatus10has a mounting feature127for mounting the apparatus to a support apparatus.

The mounting feature127may be integrally formed with part of the main housing of the base unit50of the apparatus10. In the form shown, the mounting feature127is integrally formed with the left side wall109the lower chassis104of the housing100. The mounting feature127could instead be integrally formed with any of the other walls of the housing100, such as a rear wall, right side wall, or other wall.

The main housing100of the apparatus may be formed from any suitable material that will allow the mounting feature127to be integrally formed. For example, the housing100may be formed from polycarbonate.

The integral mounting feature127has greater impact strength compared to an additional, screwed in part. Strengthening of the mounting feature127may also be done by, for example, varying the wall thickness, ribbing, or varying in internal geometries.

FIG.3shows a humidifier liquid chamber151for use with the breathing assistance apparatus10. The chamber151is a removable liquid chamber to be filled with liquid such as water for the humidification of respiratory gases. The liquid chamber151is removable from the base unit50of the breathing assistance apparatus10to be more easily re-filled or disposed of.

The liquid chamber151has a body152having a peripheral wall153and a roof156. The body defines an internal chamber for receipt of a liquid. A base154is provided at the lower end of the peripheral wall, and comprises a base flange155that projects outwardly from the lower end of the peripheral wall153. First and second base unit connection ports comprising a liquid chamber gas inlet port157and a liquid chamber gas outlet port159are in communication with the internal chamber of the liquid chamber151. The breathing assistance apparatus base unit50comprises complementary chamber connection ports comprising a gas outlet port161and a humidified gas inlet port163. When the liquid chamber is received in the recess108to engage with the housing100, the liquid chamber gas inlet port157connects to the gas outlet port161that receives gases from the motor module via a gasflow passage, and the liquid chamber gas outlet port157connects to the humidified gas inlet port163to deliver humidified gases from the liquid chamber to the patient outlet port30.

The liquid chamber151could have a generally circular peripheral shape, or could be any other suitable shape, with the recess108shape modified accordingly if required.

In the form shown, the liquid chamber151has a substantially cylindrical shape.

The base154of the liquid chamber151is heat conductive. In particular, the base154of the liquid chamber151is made from a highly heat conductive material, which allows heating of the liquid in the chamber when in contact with the heater plate140of the base unit50of the breathing assistance apparatus10during use.

The liquid chamber151can be fluidly coupled to the base unit50of apparatus10in a rearward insertion direction CID of the liquid chamber151into the recess108, from a position at the front of the housing100in a direction toward the rear of the housing100. The gas outlet port161is in fluid communication, via a fixed L shaped elbow, with a gas flow passage from the motor/impeller unit.

The humidified gas inlet port163is embodied in a removable component comprising removable elbow171(FIGS.6to13) that can be removably connected to the housing. The removable elbow171is L-shaped, and further comprises the upstanding patient outlet port30for coupling to the patient breathing conduit16to deliver gases to the patient interface17. In different configurations, the removable component may not have an elbow shape, and could instead, for example, have aligned inlet and outlet ports.

The gas outlet port161, humidified gas inlet port163, and patient outlet port30each comprise soft seals such as wiper seals, L-seals, X-rings, or O-rings to provide a sealed gases passageway between the apparatus10, the liquid chamber151, and the patient breathing conduit16and optionally one or more other accessories.

The gas outlet port161and gas inlet port163comprise multiple sealing elements. The sealing elements may be wiper seals, L-seals, X-rings, or O-rings. The wiper seals may have a T-shaped cross-section. The gas outlet port161and the gas inlet port163may each comprise two, three, or more sealing elements. In one configuration, each of the gas inlet port163and gas outlet port161comprises a pair of wiper seals. In this configuration, the gas inlet port163has two wiper seals positioned adjacent each other on the gas inlet port163. Similarly, the gas outlet port161comprises a pair of wiper seals positioned adjacent each other on the gas outlet port161. The pair of wiper seals (or of the other types of sealing elements) on each port161,163improves the seal with the corresponding base unit connection ports157,159and provides improved protection against liquid ingress into the interior of the housing of the base unit50of the apparatus where electronics are located. When the liquid chamber151is coupled to the gas inlet port163and gas outlet port161of the base unit50, one wiper seal may be positioned inside each base unit connection port157,159and one wiper seal may be located outside each base unit connection port157,159, when the liquid chamber is assembled with the base unit50. Alternatively, both wiper seals are positioned inside the respective base unit connection ports157,159when the liquid chamber151is assembled onto the heater plate140in the recess108. The arrangement of using two wiper seals per port161,163provides redundancy for liquid ingress. Similar arrangement can be used for L-seals, X-rings, or O-rings. The gas outlet port161and gas inlet port163of the base unit50are structured to have an elongate portion; i.e., a length of the ports161,163is such that the wiper seals, L-seals, X-rings, or O-rings are retained on the ports161,163.

The gas inlet port157of the liquid chamber is complementary with the gas outlet port161of the breathing assistance apparatus base unit50, and the gas outlet port159of the liquid chamber is complementary with the humidified gas inlet port163of the breathing assistance apparatus base unit50. The axes of those ports may be parallel and/or horizontal enable the liquid chamber151to be inserted into the recess108in a substantially linear movement to form gas connections between the ports.

The chamber connection ports161,163are parallel cylindrical features extending from the housing of the breathing assistance apparatus base unit50. The ports161,163will typically have an equal profile, and equal length, and axes located on the same horizontal plane. The ports161,163will typically terminate on the same vertical plane at their distal ends. The ports161,163have a port separation distance or pitch, which is the horizontal distance between the centre or axis of each port161,163. This is substantially equal to the horizontal distance between the centres of the base unit connection ports157,159of the liquid chamber.

The chamber connection ports161,163(which in the form shown are male connection members) of the breathing assistance apparatus base unit50insert into the base unit connection ports157,159(which in the form shown are female connection members) of the liquid chamber in a concentric manner. The inner diameter of the base unit connection ports157,159is larger than the outer diameter of the chamber connection ports161,163.

The liquid chamber151may initially be inserted into the recess108on an angle, and then tilted to be substantially horizontal, so that a rear part of movement of the liquid chamber151is substantially linear. The recess108may comprise one or more guide rails to assist with holding the liquid chamber in position in the recess108.

The breathing assistance apparatus10may have any one or more of the features and/or functionality of the breathing assistance apparatus described and shown in WO2016/207838A9 (WO'838). The contents of that specification are incorporated herein in their entirety by way of reference.

In order to prevent gas leaking from either of the two connections (port157to port161, and port159to port163), one or more sealing elements are provided for each connection. The one or more sealing elements may be on the outer surface of male ports, and seal against the inner surface of female ports. In one configuration, the gas inlet port157of the liquid chamber and the gas outlet port159of the liquid chamber are the female ports, and the housing ports, i.e. the gas outlet port161and the humidified gas inlet port163are the male ports. Alternatively, the ports157,159of the liquid chamber may be the male ports and the ports161,163of the breathing assistance apparatus base unit50may be the female ports.

FIGS.6to12show details of the removable elbow171. Although this section describes the features of the humidified gas inlet port163and its interaction with the gas outlet port159of the liquid chamber, including a seal173, the features of the gas outlet port161of the housing and its interaction with the gas inlet port157of the liquid chamber will be the same.

The humidified gas inlet port163comprises a generally horizontally oriented extended portion162that is configured to insert within the gas outlet port159of the liquid chamber. The terminal end163aof the port has a rounded edge to aid in aligning the gas outlet port159with the humidified gas inlet port163. Additionally, the terminal end163ais slightly smaller in diameter than the gas outlet port159.

At least one recessed portion163bis provided on the port163. This recessed portion allows a seal173to be attached to the port. The seal173can be attached by being overmoulded directly onto the port163. Alternatively, the seal173can be stretched over the terminal end163aof the port in order to place it in the recess163b. The seal may be shaped so that it remains in a stretched state once it has been placed in the recess, to assist with maintaining the seal in position. Once the seal173is located in the recess163b, the boundaries of the recess163bprevent any movement of the seal173along the port163. This allows the liquid chamber151to be connected/disconnected in a lateral motion without dislodging the seal173from the port163.

The humidified gas inlet port163may comprise a plurality of seals or sealing elements located in the recess163b. The plurality of seals175may be a pair of wiper seals, L-seals, X-rings, or O-rings. The wiper seals may have a T-shaped cross-section. In some configurations, the gas inlet port163may comprise three or more seals or sealing elements. A similar seal arrangement can also be on the outlet port161of the base unit50. The wiper seals, i.e. double seals, prevent or reduce breathing gas leak and/or condensate from moving towards the electronics in the removable elbow171and the electrical connector178(described below) of the elbow. Similarly, the seals reduce the chance of, and preferably prevent, liquid, i.e. condensate, from moving and dripping back into the gas outlet port161of the base unit50to prevent water ingress into the electronics chamber of the base unit.

The seal173may be made from silicone rubber. In an alternative configuration, the seal173could be made from any suitable elastomer, such as polyurethane. Alternatively, the seal173may be made from thermoplastic elastomer(s) and/or thermoplastic vulcanisate(s), particularly if the seal will be overmoulded onto the removable elbow.

As discussed above, a plurality of sealing elements may be provided on the port163in order to seal against the port159of the liquid chamber at a plurality of locations. The plurality of sealing elements could be achieved by having a plurality of seals173, with the port163having a corresponding plurality of recesses163bto accommodate each seal. Alternatively, in the configuration shown, the plurality of sealing elements175are incorporated into a single seal173that is located in a single recess163b.

Having a plurality of sealing elements175on a single seal173is preferable to having a plurality of seals on the port163, as it reduces the number of seals that need to be attached during manufacturing. Additionally, the increased width of the seal when providing a plurality of sealing elements175reduces the chance of the seal turning inside out during assembly onto the port163.

Having a plurality of sealing elements175is beneficial in providing redundancy in the seal between the breathing assistance apparatus base unit50and the liquid chamber151. This reduces the chance of a breathing gas leak and/or liquid moving into the base unit50occurring as it would require the seals provided by each of the sealing elements175to fail. Additionally, having one sealing element175, i.e. a forward sealing element, closer to the terminal end163aof the port163(compared to a single centrally-located sealing element) allows a seal to be formed between the liquid chamber151and the breathing assistance apparatus10even if the liquid chamber is not fully connected onto the port163. Having a plurality of sealing elements175also helps to align the liquid chamber151in the recess108and align the ports159,163, by providing multiple points of contact between the ports159,163. The rearmost sealing element175on the port163limits the position of the liquid chamber151more than the forward sealing element on the port. That is because the rearmost sealing element is further from the centre of the liquid chamber151, so tolerance between that sealing element and the liquid chamber port159,163equates to a smaller available amount of angular rotation of the liquid chamber151.

When a plurality of sealing elements is provided, the sealing elements may be spaced equally apart with respect to each other along the base173a. In other configurations, the distance between the sealing elements may not be equal.

In some configurations, the distance between the sealing elements is equal to the distance between the forward sealing element and the terminal end163aof the gas inlet port163. In other configurations, the distance between the sealing elements may not be equal to the distance between the forward sealing element175and the terminal end163a.

The forward sealing element is the primary sealing element, and the rearmost sealing element is the secondary sealing element. The sealing elements create an effective outer diameter of the ports161,163of the base unit50which is slightly larger than the inner diameter of the ports157,159of the liquid chamber, prior to connection.

The elastomeric nature of the seals allows for connection between the rigid bodies of the ports157,159,161,163. Having multiple sealing elements175allows for a pneumatic seal between the base unit50of the breathing assistance apparatus10and the humidifier liquid chamber151, even if one seal fails.

The degree to which a successful seal is created is dependent on the depth of the base unit connection port157,159of the liquid chamber into which the corresponding chamber connection port161,163of the breathing assistance apparatus base unit50locates so that one or more seal elements175are engaged. This assumes the diameter of the chamber connection ports161,163, base unit connection ports157,159, and seals175are of appropriate dimensions to allow one or more seals to engage. Advantageously, both seals175are engaged to minimise any possible rotation or rocking of the liquid chamber151, by constraining an additional degree of freedom, during use as well as to provide the pneumatic seal. Engaging both seals175also provides redundancy if a singular seal were to fail.

It should be understood that while a complete seal between the base unit connection ports157,159of the liquid chamber and the chamber connection ports161,163of the breathing assistance apparatus base unit50, some leakage may be accommodated between those components while still providing sufficient gas flow to a user.

One or more of the sealing elements175may be a wiper seal. In the form shown inFIGS.7and11, the wiper seal is a flexible annular rim that runs around the circumference of the port163. As shown in the cross-section inFIG.12, the wiper seal has a bulbous radially outwardly located tip175awhich may have a circular cross-section for example. The tip175ais configured to contact the inner surface of the base unit connection port159of the liquid chamber. The wiper seal may advantageously have a narrowed web section175bleading from the base of the seal to the tip175a. The narrowed web section175ballows the wiper seal to flex more easily, while the enlarged bulbous tip175aprovides a larger surface area for the sealing contact with the inner surface of the base unit connection port159of the liquid chamber. In some configurations, the wiper seal may not have the bulbous tip175a.

Referring toFIG.12, the radial height h1, h2of each wiper seal is such that in an unflexed position, the diameter of the wiper seal is greater than the inner diameter of the base unit connection port159of the liquid chamber. When the liquid chamber151is inserted into the recess108, the wiper seal will contact the inner wall of the base unit connection port159of the liquid chamber and will flex downwards towards the base173aof the seal173to accommodate the smaller inner diameter of the base unit connection port159of the liquid chamber. The elasticity of the seal will mean that the wiper seal175resists this flexing, thereby providing a sealing force between the points of contact on the base unit connection port159of the liquid chamber and the tip175aof the wiper seal. This configuration accommodates slight variations in sizes of both the wiper seals175and the port159of the liquid chamber due to manufacturing tolerances, as the wiper seals would flex to accommodate the exact diameter of the liquid chamber port.

Another advantage of the wiper seals175is the low resistance they provide to axial movement. Unlike other seals, the wiper seals' ability to flex and conform to the inner surface of the base unit connection port of the liquid chamber results in a low amount of friction, thereby making it easier to connect and disconnect the liquid chamber151from the housing100of the base unit50of the breathing assistance apparatus10.

A wiper seal175does, however, provide slightly more resistance movement of liquid chamber151in one scenario. When the liquid chamber is being moved in a first direction (e.g. towards the housing100in an insertion direction CID when being connected), the wiper seal175will be flexed in a first orientation. When the liquid chamber is being moved in a second direction (e.g. away from the housing100in a removal direction CRD when being disconnected), the wiper seal175will be flexed in a second orientation. Therefore, when the liquid chamber151first moves in one direction after moving in the other direction, the wiper seal175will also swap from one orientation to the other. This occurs by the wiper seal175folding over itself in the gap between the base173aof the seal and the inner surface of the liquid chamber port159. This folding results in the wiper seal175flexing more than it regularly would during ordinary movement of the two components, and as such temporarily provides greater resistance to movement of the liquid chamber151than usual.

This increased resistance can be beneficial, as it will likely occur after the liquid chamber151has been connected, right before the user initially attempts to remove the liquid chamber from the recess108. In this situation, the effect of the wiper seal175changing orientation would provide a temporary resistance that needs to be overcome before the liquid chamber175can removed. This helps prevent the liquid chamber151from accidentally becoming dislodged from engagement with the breathing assistance apparatus10, but does not inhibit the removal of the liquid chamber151once it has begun moving relative to the housing100.

In an advantageous configuration, the chamber connection ports161,163of the breathing assistance apparatus base unit50would each have a single seal173located in a single recess, the seal having two sealing elements175in the form of two wiper seals. The wiper seal closer to the terminal end163aof the gas port163could have a larger diameter than the other wiper seal (i.e. h1>h2). A longer wiper seal provides a more reliable seal and accommodates variation in the inner diameter of the respective base unit connection port157,159of the liquid chamber, but also requires a greater amount of travel in order to settle in the correct position. This greater amount of travel is provided by the liquid chamber151contacting the front wiper seal earlier when connecting the liquid chamber.

In an alternative configuration, the wiper seal closer to the terminal end163aof the gas port163could have a smaller diameter than the other wiper seal (i.e. h2>h1), but due to an internal taper of the ports157,159of the liquid chamber151, there will be a greater interference between the port157,159and the wiper seal closer to the terminal end163aof the gas port163than the other seal. Similarly, h1and h2could be equal, with greater interference between the port157,159and the wiper seal closer to the terminal end163aof the gas port163than the other seal, due to the internal taper of ports157,159.

In another alternative configuration, the wiper seals may have the same dimensions. In another alternative configuration, the wiper seals may have three or more sealing elements175.

In another alternative configuration, the wiper seals could be shaped to follow an internal taper of the ports157,159, so that there is the same interference between each wiper seal and the port157,159.

Alternatives to the wiper seal include using an O-ring, L-seal or an X-ring. A wiper seal is preferred to these alternatives as it provides less resistance to the movement of the liquid chamber151, and is easier to assemble and replace. The O-ring and X-ring have the advantage of having a higher pressure threshold; however, the pressure threshold for the wiper seal exceeds the pressures that would be used in the breathing assistance apparatus10.

As a further alternative, one or more wiper seals could be used in addition to one of the alternative types of seals listed above or other suitable seal(s).

As shown inFIGS.11and12, the seal173has a further sealing element at or adjacent an opposite end of the seal173from the terminal end163aof the gas port163. In one configuration, the base173aof the seal173also has an outward taper173bleading to a radially projecting flange177. The flange177is positioned at or adjacent an end of the seal173that is at or adjacent the proximal end163bof the port163that is opposite to the terminal end163a. The flange177is configured to form a seal with a component that differs from the first component (the base unit connection port157,159of the liquid chamber). Therefore, the flange177has a configuration that differs from the wiper seals175. In the form shown, the flange projects radially further outwardly than the wiper seals175, so that the portion of the seal173with the flange has a larger diameter to connect with a second component having a larger internal diameter than the liquid chamber port157,159. The outward taper173bassists with guiding the different component into contact with the flange175.

For example, the larger component may comprise part of a disinfection kit.FIG.13shows the components of a disinfection kit180connected to the base unit50of the breathing assistance apparatus10. A disinfection tube181is connected to the gas outlet port161and the patient outlet port30. An inner surface of a first coupling181aof the disinfection tube181forms an interference fit with the flange177on the seal173on the gas outlet port161. The first coupling181amay have a tapered surface that forms the interference fit. An inner surface of a second coupling181bof the disinfection tube181forms an interference fit with a seal on the patient outlet port30.

A filter cap183is connected to the humidified gas inlet port163. An inner surface of the filter cap183forms an interference fit with the flange177on the seal173on the humidified gas inlet port163. The filter cap183may have a tapered surface that forms the interference fit.

In one configuration, the disinfection tube181and the filter cap183do not contact the wiper seals175, due to the larger diameter of the flange177. This means that the disinfection kit may operate to disinfect the wiper seals175as well as the ports161,163,30, and elbow171. In an alternative configuration, the disinfection tube181and the filter cap183could seal with the wiper seals175in addition or as an alternative to the seal formed with the flange177.

In an alternative configuration, the flange177could be an integral part of the port161,163instead of the seal173, and therefore made of hard plastic. In this configuration the disinfection tube181and filter cap183could still form an interference fit between the tapered surfaces and the flanges177.

The terminal ends161a,163aof the ports161,163may contact a step on the internal surface of the liquid chamber151, thereby limiting the insertion depth of the ports161,163during use. The flange177and taper173bwould not have any interaction with the liquid chamber151during use of the device, as the liquid chamber151does not contact the flange177and/or taper173b. In an alternative configuration, the liquid chamber151could contact the flange177and/or taper173b. This contact could result in an additional seal between the breathing assistance apparatus10and the liquid chamber151.

The flange175and taper173bcan serve an additional purpose of providing a surface for the user to push on when connecting the removable elbow171to the housing100.

The base unit50of the apparatus comprises a shroud190that cooperates with the housing100and the removable elbow171.FIG.6shows the removable elbow171connected to the shroud190. As shown inFIG.2for example, the shroud190serves to create a uniform upper surface of the housing100of the apparatus10, with the patient outlet port30of the removable elbow171protruding upwardly through the shroud190. The shroud190is configured such that it is not removable from the housing100in normal use of the apparatus10.

As shown inFIGS.6and9, the shroud190comprise a body191having a substantially flat horizontal upper surface193, two contoured shoulders195having a substantially sinuous configuration that extend downwardly and outwardly from opposite sides of the upper surface193, and two substantially vertical downwardly extending outer side walls197. A recess199extends rearwardly into the upper surface193from a forward edge193aof the upper surface193. The recess199is sized and configured to receive part of the removable elbow171, to provide an unobstructed path for the removable elbow171to be connected to the housing100of the base unit50of the apparatus10. In the form shown, the recess is defined by a pair of substantially parallel side walls199aand an upper arcuate rear wall portion199b. A contoured tapering rear wall region199cprojects into the recess from the arcuate rear wall portion, and is positioned beneath the arcuate rear wall portion199b. The contoured tapering rear wall region is configured to receive a chimney179aof the removable elbow.

Similarly, the removable elbow171has a flat horizontal tab172extending from the elbow that has a shape that is complementary to the shape of the recess199in the shroud, such that when the removable elbow171is assembled with the apparatus10, the flat horizontal tab172is received in the recess199to create a uniform surface. This tab172can additionally provide an upper surface for the conduit16to contact when connecting the conduit16to the patient outlet port30of the elbow.

As shown inFIGS.7and8for example, the flat horizontal tab172can have a thinned portion172aadjacent the terminal forward end portion172b, located between the patient outlet port30of the elbow and the terminal forward end portion172bof the tab. This allows the terminal forward end portion172bto flex vertically relative to the rest of the elbow171.

The flat horizontal tab172also has engagement features comprising two protrusions174extending outwardly from opposite sides of the terminal forward end portion172bof the tab. The protrusions174are configured to interact with engagement features comprising complementary engagement recesses201extending outwardly from either side wall199aof the recess199of the shroud of the housing, on the underside of the shroud, as shown inFIGS.10and14. The removable elbow171is configured to connect to the housing by moving the removable elbow in a first direction relative to the housing (rearwards towards the housing). The removable elbow171is configured to disconnect from the housing by moving the removable elbow171in a second direction (forwards relative to the housing) that is opposite to the first direction. Due to the interaction of the engagement features, the removable elbow171is configured to inhibit movement of the removable elbow171in the second direction in the absence of actuating part of the removable elbow, e.g. the terminal forward end portion172b, relative to another part of the removable elbow to flex the tab. That inhibits removal of the removable elbow171from the shroud190of the housing100.

The rear portion of each protrusion174is designed with an angled surface174a(FIG.10). When the elbow171is inserted into the housing100, this surface174acontacts the underside of the front edge193aof the shroud, causing the terminal end172bof the tab to flex downwards by bending in the thinned section172a. Once the elbow171has been fully inserted, the protrusion174will reach the complementary engagement recess201in the shroud. At this point the protrusion174will engage with the recess201as the tab172flexes back into a flat and horizontal position. When engaged, the front surface174bof the protrusion will contact a complementary surface201bof the engagement recess.

The front surface174bof the protrusion is steeper, i.e. more vertical, than the rear surface174a, such that if a user attempts to pull out the elbow171from the shroud190, and thereby from the housing100, the contact between the front surface174bof the protrusion and the complementary surface201bof the recess should not cause the tab to flex downwards, unless a sufficiently high force is applied to the elbow171.

In an alternative configuration, the removable elbow171and shroud190may each have a single one of the engagement features174,201, rather than each having two engagement features.

In order to remove the elbow171from the housing100, the user would typically first press downwards on the upper surface of the terminal forward end portion172bof the tab172, in order to actuate that part of the tab172by flexing the tab and disengage the protrusions174from the engagement recesses201. Only once the tab has been flexed can a user then pull the elbow171out from the housing100. One advantage of this is that it helps prevent the elbow171from coming loose when the liquid chamber151is being removed from the apparatus by pulling the liquid chamber151out of the recess108.

This configuration allows a user to easily assemble the elbow171with the housing100in a single one-handed motion, but requires more complex interaction to then disassemble it. If a user does not understand how to correctly remove the elbow171and attempts to remove the elbow by pulling on it without actuating the tab172, the engagement features will ultimately disengage from each other under a sufficiently high force. This will avoid damage of the removable elbow171and/or shroud190.

In an alternative configuration, the engagement features may be configured such that the removable elbow171cannot disconnect from the shroud190of the housing100in the absence of actuating the tab172, e.g. the terminal forward end portion172b. This could be achieved by having vertical front surfaces174b,201brather than angled front surfaces.

FIG.11schematically shows a position176of temperature sensor(s) such as thermistor(s) in the removable elbow171. The thermistors are located in the rear vertical wall of the upstanding portion of the elbow, close to the curved transition region between the vertical and horizontal elbow portions. At this location, the thermistors are relatively shielded from the heat produced by the heater plate140, allowing for more accurate estimations of the temperature of gases flowing through the removable elbow171to be made.

The elbow171has electrical connectors179positioned in an upstanding chimney179a, the connectors configured to provide power from a main power board of the apparatus10to the heater wires16ain the conduit16.

As mentioned above, the shroud190is designed to not be removed during regular use. The shroud has features that allow it to be clipped onto a screen carrier211, which in turn is fastened to the upper chassis102to become part of the housing100. The screen carrier211can connect to and support a display212. In alternative configurations, the screen carrier211may not be provided, and the shroud190may clip directly to part of the housing100, such as an upper surface or upper chassis102of the housing.

FIGS.16to19show features on the shroud190and screen carrier211for attaching the components together without the use of fasteners. The shroud190is configured to attach to the screen carrier211of the housing100via two movements; an initial movement of the shroud in a first direction followed by a subsequent movement of the shroud in a second direction that is offset from the first direction. In one configuration, the second direction is transverse to the first direction. In the form shown, the shroud190is configured to initially be moved in a first downward direction DD, followed by a movement in a second rearward direction RD, relative to the screen carrier211and thereby the housing100. In the form shown, the downward direction DD is vertical and the rearward direction RD is horizontal.

The shroud190is configured so that the shroud cannot be detached from the screen carrier211of the housing solely by pulling the removable elbow171in the second forwards direction relative to the housing100.

As shown inFIGS.17and18, each side197of the shroud190is shaped to be complementary to the shape of the screen carrier211. The sides of the screen carrier211of the housing100have two forwardly directed horizontal protrusions213(one per side wall) that engage with complementary rearwardly open recesses194in rear walls on each side of the shroud190as the shroud is moved in the rearward direction relative to the housing. Once the shroud190is connected to the screen carrier211, the horizontal protrusions213being received in the recesses194prevent vertical movement of the shroud190.

Similarly, the screen carrier211of the housing100has an upstanding vertical protrusion215on each side that engages with a complementary downwardly open recess196in the bottom of each side wall197of the shroud as the shroud is moved in the downward direction relative to the housing. Unlike the horizontal protrusions, the vertical protrusion215is narrower than the complementary recess196in the shroud. This allows for a small amount of horizontal movement in the rearward direction RD as shown inFIGS.17and18. The vertical protrusion215and recess196aid in aligning the shroud190with the screen carrier211during assembly.

The shroud190is first placed above the screen carrier211and moved in the downward direction DD to the position shown inFIG.17. The shroud is then slid horizontally in the rearward direction RD such that the horizontal protrusions213engage with the complementary recesses194in the shroud, as shown inFIG.18.

The shroud190and screen carrier211may have a second set of forwardly extending horizontal protrusions213aand rearwardly open recesses194atoward a forward end of the screen carrier211and shroud190, to further inhibit vertical movement of the shroud190relative to the screen carrier211.

The shroud190and screen carrier211of the housing100additionally have features to inhibit horizontal movement of the shroud relative to the screen carrier when they are fully engaged in the position shown inFIG.18, to therefore inhibit removal of the shroud from the housing. As shown inFIGS.14-16and19, the shroud has one or more downwardly extending engagement protrusions198(two in the configuration shown) that extend downwards from the back of the lower surface of the shroud190. The engagement protrusions198are configured to engage with complementary upwardly extending engagement protrusion(s)217extending from an upper surface of the screen carrier211. Both sets of engagement protrusions198,217have a first side198a,217awith a relatively flat angle, and a second side198b,217bwith a relatively steep angle. When attaching the shroud190to the screen carrier211by moving the shroud in the rearward direction RD, the first sides198a,217aof each set of engagement protrusions will interact with each other by contacting each other, and the relatively flat angle on the surface of each engagement protrusion will cause the shroud190to briefly and easily flex as the engagement protrusions clip into place. That is, the first sides198a,217aare configured to interact with each other when attaching the shroud to the screen carrier.

Once the shroud190is connected to the screen carrier211, the second sides198b,217bof each set of protrusions will contact each other. The steeper angle on the surface of the second sides198b,217bof the engagement protrusions means that a larger horizontal force is required in order to cause the shroud190to flex in the same way as before. The result of this is that assembly of the shroud190and screen carrier211requires less force than disassembly. The second sides198b,217bare configured to interact with each other once the shroud is attached to inhibit removal of the shroud from the screen carrier of the housing. The shroud can still be removed by moving the shroud190forwards in direction opposite to the rearward direction RD, if a large enough force is applied. However, this would only be done by a technician if some form of maintenance were being performed on the apparatus. The features above are designed such that the shroud190would not be removed during normal use (even accidentally).

It can be seen fromFIGS.14-19that the engagement features on the shroud190and screen carrier211are such that the upper surface of the screen carrier can be configured so that there are no, or a minimal number of, exposed fasteners (such as screws) on the underside of the shroud and the upper surface of the screen carrier, meaning that the shroud and upper surface of the screen carrier are easy to clean.

Referring toFIGS.14to16, the shroud190has a downwardly projecting forward wall190athat is complementary to a surface211aof the screen carrier211of the housing. The forward wall190ais configured to contact the surface211aof the screen carrier211when the shroud is attached to the screen carrier. In the form shown, the forward wall190aand the surface211aare arcuate, to follow the shape of a rear wall of the recess108for receipt of the liquid chamber151. Alternatively, the forward wall190aand the surface211acould have different shapes, such as a substantially straight shape for example.

Once the shroud190is assembled with the screen carrier211, the forward wall190aand surface211acontact each other. This avoids an exposed gap between forward portions of those components, which would need to be cleaned if the gap was present. Due to the tight complex geometry, such a gap would be difficult to clean, which might mean the shroud would need to be removed for satisfactory cleaning. Avoiding such a gap enables the shroud190to be non-removable or difficult to remove, without creating cleaning issues.

The removable elbow171is removable from the housing100when the shroud190is attached to the housing.

In an alternative configuration, one or more of the engagement protrusions198,217can be replaced with an engagement recess. One side of the engagement recess would have a surface that is complementary to the second side of the engagement protrusion in order to inhibit disassembly in a similar way to the above configuration. In a further configuration, one or more of the engagement protrusions198,217could be replaced with a combination of an engagement protrusion and engagement recess, such that a complementary engagement protrusion engages over the engagement protrusion and within the engagement recess.

A similar shroud190and screen carrier211and/or housing100engagement configuration could be used where the shroud190acts as a cover for part of the housing or another component, but where the component that is covered is not removable.

Referring toFIGS.7and8, the removable elbow171also includes an electrical connection. The elbow171has an inlet for pneumatically connecting to a first accessory for the breathing assistance apparatus10, such as the liquid chamber151, an outlet for pneumatically and optionally electrically connecting to a second accessory for the breathing assistance apparatus, such as the patient conduit16, and a printed circuit board (PCB) electrical connector178for electrically connecting to the breathing assistance apparatus10to form an electrical connection with an electrical component in the housing. The electrical connection provides an electrical link between the base unit50of the apparatus10and the temperature sensors176embedded in the elbow, as well as between the base unit50of the apparatus10and the conduit16(when the conduit has one or more sensors and/or a heating element), via an electrical interconnecting assembly221in the housing which will be described below. The PCB electrical connector178electrically connects to the electrical interconnecting assembly221when the removable elbow171is connected to the housing100.

The pneumatic inlet connection of the removable elbow171is provided by the humidified gas inlet port163, the pneumatic outlet connection is provided by the patient outlet port30, and the outlet electrical connection is provided by connectors179(FIG.9) that are provided in the chimney179athat extends upwardly parallel to an axis of the port30.

The humidified gas inlet port163and the patient outlet port30are in fluid communication with each other via a gas flow path in the removable elbow. Electrical connectors178,179of the removable elbow are pneumatically isolated from the gas flow path between the humidified gas inlet port163and the patient outlet port30, via at least one wall of the removable elbow. For example, the body of the removable elbow may be injection moulded plastic material, with isolated regions provided for the electrical connectors that are separate and isolated from the gas flow path.

Because the portion of the removable elbow, namely PCB electrical connector178, that is configured to form the electrical connection with the electrical component in the housing (the electrical interconnecting assembly221) is pneumatically isolated from the gas flow path of the removable elbow, coupling the removable component to the housing solely provides an electrical connection between the PCB electrical connector178and the electrical interconnecting assembly221. It does not form a direct pneumatic connection between the gas flow path in the removable elbow171and the housing100. Instead, the gas flow path in the removable elbow provides a pneumatic connection between the first accessory (the liquid chamber151) and the second accessory (the patent conduit30).

In the configuration shown, the PCB electrical connector178is partly housed in a housing178athat is integrally formed with the elbow. The PCB electrical connector projects rearwardly from the housing178ato insert into an electrical connector on the base unit50of the apparatus10in a horizontal direction (i.e. the same rearward insertion direction CID in which the liquid chamber151connects to the housing100of the base unit50and the same rearward direction RD in which the shroud190connects to the screen carrier211). As such, the removable elbow171can be horizontally connected to the apparatus in the rearward direction RD, with the liquid chamber151being horizontally connected to the two apparatus ports161,163after that. Alternatively, the liquid chamber151can initially be connected to the removable elbow171, with the assembled liquid chamber151and elbow171then being connected to the base unit50of the apparatus together by moving them in the rearward direction together.

This allows the components to be assembled and disassembled in multiple ways. Specifically, the elbow171will make three connections during assembly. These three connections are the connection between the elbow171and the patient conduit16, the connection between the elbow171and the liquid chamber151, and the connection between the elbow171and the housing100. Each of these three connections can be made in any order. Similarly, when disassembling the components, these three connections can be broken in any order. This is advantageous as different orders of assembly and disassembly may be preferred in different scenarios.

For example, the removable elbow171may be assembled with the housing100initially as the removable elbow may have come assembled with the housing100, with the liquid chamber151and the conduit16not being attached until the apparatus10is to be used. As the removable elbow171is removed much less frequently than the liquid chamber151and/or conduit16, this will be the most common order of assembly. Additionally, in a hospital setting, the liquid chamber151and conduit16would be replaced between each patient, while the removable elbow171may only be cleaned/disinfected between uses. As such, the removable elbow171can be assembled with the housing100after being cleaned, with the liquid chamber151and conduit16again only being connected when a patient needs to use the apparatus10.

The liquid chamber151and conduit16may also be removed prior to removing the elbow171after the apparatus10has been used in order to first throw these components away, with the removable elbow171then remaining with the apparatus10until it is to be cleaned. The removable elbow171may be cleaned while connected to the housing100through use of a disinfection kit as described above.

The conduit16and/or liquid chamber151may be preassembled with the removable elbow171after having cleaned the elbow171, thereby allowing all three components to be able to quickly connect to the housing100in one motion when required.

The removable elbow171may be disconnected from the housing100with the conduit16and liquid chamber151still attached, which may be useful, for example, in situations in which the patient has a particularly infectious disease. In these situations, it may be desirable to disconnect the removable elbow171in this way, such that the circuit is largely still contained and can easily be thrown away in its entirety.

Connecting and disconnecting the preassembled removable elbow171, conduit16and liquid chamber151to/from the housing100is facilitated by the removable elbow171and liquid chamber151connecting in the same direction (i.e. rearwardly in a horizontal direction), as well as the shroud190not needing to be attached over the removable elbow171after the removable elbow171has been inserted.

As shown inFIGS.28to36, the PCB electrical connector178of the removable elbow171inserts into an electrical interconnecting assembly221of the base unit50of the apparatus10. The interconnecting assembly221is made up of three components; a socket231, a PCB241, and an overmould251. The socket defines a receptacle to receive the PCB electrical connector of the removable elbow.

As shown inFIGS.29and30, the socket231comprises a housing232that defines a receptacle233to receive the PCB electrical connector178of the removable elbow171. A forward portion233aof the receptacle233has relatively large vertical and horizontal dimensions to receive the housing178aof the electrical connector. A rear portion233bof the receptacle233has relatively small vertical and horizontal dimensions to receive the portion of the PCB electrical connector178that projects rearwardly from the housing178a. The rear portion233bis defined between upper and lower ribs234that extend into the rear part of the receptacle from upper and lower walls thereof. The rear portion233bof the receptacle is configured to form a close or tight fit with the PCB electrical connector178to assist with holding the removable elbow171in connection with the socket231via contact between the rear portion233bof the receptacle and the PCB electrical connector178. The forward portion233aof the receptacle may be configured to form a close or tight fit with the housing178aof the PCB electrical connector178to assist with holding the removable elbow171in connection with the socket231. Alternatively, that may form a looser fit.

The interaction of the socket231with the PCB electrical connector178and/or housing178a, and the interaction of the protrusions174and engagement recesses201, form two spaced apart engagement regions of the removable elbow171and the housing100(via the shroud190); at or adjacent a rear part of the removable elbow and at or adjacent a forward part of the removable elbow. This assists with securing the removable elbow to the housing, reducing the likelihood of the removable elbow171inadvertently being removed from the housing100when the liquid chamber151is being removed from the recess108.

Forward edges234aof the ribs234are angled such that there is a taper region between the forward portion233aand rear portion233bof the receptacle233, to assist with guiding the PCB electrical connector178into engagement with the rear portion233bof the receptacle233.

The socket231has multiple features to hold it in place with respect to the housing100of the apparatus10. As shown inFIG.31, two fastener apertures235are located on opposite sides of the socket231. These apertures235are designed for receiving fasteners, such as screws, in order to fasten the socket231to the upper chassis102of the housing, thereby securing the interconnecting assembly to the housing100. As shown inFIG.27, an upper angled surface131of the upper chassis102that is configured to receive the screen carrier211, has two complementary apertures132for receipt of the fasteners.

The socket231also has a mounting protrusion236extending downwardly from the underside of the body232of the socket. The mounting protrusion236is configured to engage with a complementary recess133on the angled upper wall131of the upper chassis102of the housing. In the configuration shown, the mounting protrusion236has a cross-shaped cross section, wherein the width and length of the cross will match the internal diameter of the circular recess133. The engagement between the mounting protrusion236and the recess133prevents lateral movement of the socket131relative to the housing100, such as could otherwise be caused by connecting and disconnecting the elbow171. As shown inFIG.30, the mounting protrusion236may be tapered so that its lower end has a smaller dimension than its upper end, to assist with guiding the mounting protrusion236into engagement in the recess133.

The angled projections225avisible on the side of the socket inFIGS.28and30help create a better seal between the socket231and the screen carrier211of the housing100, and help prevent liquid ingress into the screen carrier211.

As shown inFIG.33, the PCB241of the interconnecting assembly221has multiple apertures242that engage with complementary protrusions237that project rearwardly from a rear wall of the socket231in order to correctly position the two components together. More or fewer projections and apertures can be provided.

Once assembled with the housing100, the interconnecting assembly231connects with both the main power board263aand the display/interface PCB263bof the apparatus (FIG.36). The PCB241has an electrical connector243(shown on the right side ofFIG.34) that connects to the display/interface PCB263b, as well as a tab245(shown on the bottom left ofFIG.34) that forms an electrical connector to connect to the main power board263a.

The main power board263ais located between the upper chassis102and lower chassis104of the housing100. As shown inFIG.27, the angled upper surface131of the upper chassis102has a horizontal transversely extending elongate aperture134. When assembled with the interconnecting assembly221, a portion of the PCB241extends through this aperture134to connect with the main power board263a.

Due to the main power board263aoperating at high power, the main power board263ahas greater requirements for being sealed against both gases and moisture than the display/interface PCB263b. By using a PCB241in the interconnecting assembly221to connect to both the interface PCB263band the main power board263a, the main power board263acan be sealed simply by sealing the connection between the main power board263aand the interconnecting PCB241.

As shown inFIGS.34and35, an overmould251is applied to the interconnecting assembly221to provide a pneumatic seal. The overmould is provided over at least a section of the PCB. The overmould is configured to create a pneumatic seal over the covered section of the PCB and between the overmould and another component of the breathing assistance apparatus. The overmould may moulded from any suitable material, such as polyurethane for example. Any thermoplastic elastomer that is soft and adheres to the board would be suitable. Alternatively, the overmould251could be made of silicone, which exhibits less stress relaxation. An interlock may be formed to enhance the adherence between the silicone overmould and the board.

The purpose of the overmould251is to pneumatically seal the high power electrical components. The higher power electrical components are the main power board263a, the section of the PCB241that provides the electrical connection between the main power board263aand the socket231, as well as the electrical connections within the socket231itself. A portion of the PCB is exposed from the overmould251to form the electrical connector245to couple the higher power section of the PCB to the main power board263a. In the form shown, the electrical connector245comprises a male tab of the PCB that is configured to engage in a complementary female socket of the main power board263a. In an alternative connection, the electrical connector245comprises a female socket on the PCB that is configured to receive a complementary projecting tab of the main power board263a. In either configuration, the entire higher power section of the PCB, other than the electrical connector245, is advantageously encapsulated by, and pneumatically sealed by, the overmould251.

The overmould also encapsulates electrical and/or electronics elements on the PCB.

The overmould251covers a section of the PCB241as well as the connection between the PCB241and the socket231. The section of the PCB241that is covered is the section through which current flows from the main power board263ato the socket231. The remaining sections of the PCB241are used to provide current to the user interface via the display/interface PCB263b, and do not require the same level of pneumatic sealing.

Therefore, another section of the PCB is exposed from the overmould. The section of the PCB that is exposed from the overmould is a lower power section of the PCB, whereas the higher power section of the PCB is substantially covered by the overmould. The lower power section of the PCB that is exposed from the overmould leads to the electrical connector243. In the configuration shown, said electrical connector243is associated with a component having a lower power requirement than the main power board263a. For example, the display interface PCB263bthat is associated with the display has a lower power requirement than the main power board263a. Due to the lower power requirement, the portion of the PCB that leads to the electrical connector243does not need to be pneumatically sealed.

In an alternative configuration, the portion of the PCB that leads to the electrical connector243may be covered by the overmould. In yet another alternative configuration, the entire PCB other than electrical connector(s) may be covered by the overmould.

By also sealing the connection between the socket231and the PCB241, any oxygen enriched gas that leaks out around the socket231during use would be prevented from entering the socket231via gaps between the socket231and the PCB241. This is important as the socket231could be providing a large amount of power to the removable elbow171, as the elbow in turn supplies the power for heating the conduit16.

As shown inFIGS.32and36, the overmould251on the PCB241can be configured such that it forms a tight fit with the aperture134in a wall of the upper chassis102of the housing. This serves to create a pneumatic seal between the PCB241and the aperture134in order to prevent ingress of moisture and gases into the interior of the housing100, where the main power board263ais located.

Referring toFIGS.20to27, the housing of the base unit50of the apparatus10comprises a handle261connected to the upper chassis102of the housing100. The handle261is movable between a lowered storage position shown inFIG.23and a raised carrying position shown inFIG.24. In the raised carrying position, a user can use the handle to carry the apparatus10.

When the handle261is in the lowered position, an upper surface of the handle261is substantially flush with upper forward wall portions110a,110bof the upper chassis102of the housing100. A rearward peripheral upper wall portion110cof the upper chassis forms a handle recess to receive the handle in the lowered position. An indent102d(FIG.20) is provided at a rear edge of the upper wall portion110cto enable a user to insert their fingers under the handle to lift it from the lowered storage position.

Either side of the upper chassis102has an inwardly open connecting recess112for receipt of complementary connecting portions263of the handle. Although only the left side recess112is shown in the figures, the right side recess will be a mirror image thereof.

Referring toFIG.22, the recess has a substantially half-circular configuration. The recess112has a transversely shallow rear portion112aand a transversely deep forward portion112b. An arcuate slot112cextends upwardly and rearwardly from the transversely deep forward portion112band the upper end thereof is upwardly open.

The transversely deep forward portion112band the arcuate slot112cdefine the boundary for the connecting features of the handle, thereby dictating the possible positions of the handle.

FIGS.23and24show the connecting features on the connecting portion263of the handle. The connecting features comprise an arcuate arm265that extends from a position at or adjacent each end of the body of the handle. A distal end of the arm265is coupled to a tab267that projects forwardly and outwardly from the arm265. The arcuate arm265and tab267project outwardly from a planar plate264(FIG.27) that has an arcuate periphery. The planar plate264has dimensions corresponding to the dimensions of the transversely shallow rear portion112aof the recess.

The connecting features265,267of the handle261engage with the transversely deep forward portion112band arcuate slot112c. The upper edge of the arcuate arm263forms a close fit with a semi-circular upper wall of the transversely deep forward portion112bof the recess. Additionally, the arcuate slot112cforms a close fit with upper and lower edges of the arcuate arm263, so that the handle261follows the desired path of movement.

The tab267of the protrusion travels within the transversely deep forward portion112bof the recess. The length of the tab267is configured to form a close fit with the upper and lower arcuate walls of the transversely deep forward portion112b. When the handle261is lifted, the tab267rotates in the transversely deep forward portion112bwith respect to the housing10, with the tab shifting between a forward boundary wall112b′ and a substantially vertical rear boundary wall112b″ which is defined by the transversely shallow rear portion112aof the recess. When the handle reaches an approximately vertical position as shown inFIG.24, the tab267will contact the rear boundary wall112b″, thereby limiting the movement of the handle261.

Because the handle261connects to inner vertical walls of the upper chassis102, the handle is prevented from being removed once the screen carrier211is attached to the upper chassis102.

The handle261also includes an aperture268to accommodate a gas port275on a filter module271, when the filter module is received in a filter recess118in the housing and when the handle is in a storage position. The aperture268is positioned along one side member of the handle, and is positioned closer to the transverse carrying portion262of the handle261that can be used to carry the apparatus10, than it is to the connecting features263-267on that side member of the handle that movably connect the handle to the housing. The transverse carrying portion262extends from an end of the side member opposite to the end with the connecting features.

The apparatus has a removable filter module271shown inFIGS.25and26. Previous configurations of the filter module are described in WO2018/074935A1 (WO '935). Unless described below, the features and functioning of the filter module271are the same as the filter modules described in WO '935, and the contents of that specification are incorporated herein in their entirety by way of reference.

The filter module271has a filter body272having a plurality of walls including a first, front, upstanding wall272a, an opposed second, rear, upstanding wall272b, and upper wall277extending between the first wall272aand the second wall272b, and an opposite lower wall279. The body272defines one or more filter chambers. A lower gas port273defines a first inlet at a base of the filter body and fluidly couples to an outlet port307of a valve module301(FIG.40), to receive gases from the outlet port307.

An upper gas port275defining a second inlet is provided at an upper end of the filter body272and extends upwardly from the upper wall277. The upper gas port275is configured to interact with the aperture268in the handle. The upper gas port275can connect to a supplementary gas source. Ambient air inlets (not shown) are provided in the base of the filter body to allow for the entrainment of ambient air. These gases are then passed through a filter medium274of the filter271to filter gases as they exit the filter chamber(s) before being delivered to and mixed by the blower of the motor module.

The upper gas port275is in communication with at least one filter chamber, the lower gas port273is in communication with at least one filter chamber, and the ambient air inlets are in communication with at least one filter chamber. Two or more of the inlets may be in communication with the same filter chamber or with different filter chambers.

As shown inFIG.37, the lower chassis104of the housing100has a filter recess118with a shape that is complementary to the shape of the body272of the filter module271. An interior of the filter recess118is in communication with an interior of the recess122for receipt of the motor module, to enable the delivery of gases from the filter to the motor module.

Referring toFIGS.20and32, a filter recess120is provided in the upper wall portion110cof the upper chassis102, and has a shape that is complementary to the shape of the upper portion of the body272of the filter module. The recess120is positioned above the recess118when the upper chassis102is coupled to the lower chassis104.

As shown inFIGS.25and26, the upper wall277of the filter body272is angled so as to be non-parallel to the lower wall279of the filter body. The angle α of the upper wall may be between about 2 degrees and about 10 degrees, optionally between about 2 degrees and about 5 degrees, optionally about 3 degrees, relative to the lower wall. Therefore, the second wall272bis taller than the first wall272a. That is, the upper wall277is offset from horizontal when the filter module271is installed in the housing100, and is angled to match the upper surface110cof the upper chassis102of the housing100. In an alternative configuration, the upper wall277is parallel to the lower wall279.

The upper gas port275is positioned closer to one of the first wall272aand second wall272bthan it is to a centre of the upper wall277. In particular, the upper gas port275is positioned at or adjacent the second wall272bat one side of the filter body272, and in the form shown is positioned at or adjacent the higher end277aof the upper surface277. This has a number of advantages, which can be explained with reference to the handle261and housing100.

Firstly, by placing the upper gas port275at or adjacent one side of the filter body, the second inlet275only aligns with the aperture268in the handle261when the filter271is inserted in the correct orientation. If the filter were inserted backwards, the second inlet275would prevent the handle261from lying flat, indicating to a user that the filter is inserted incorrectly.

Secondly, the upper gas port275is located further from the axis of rotation of the handle261. This results in a larger radius of curvature in the path the aperture268takes when the handle is moved261. This is beneficial when a tube is connected to the upper gas port275, as the handle261is less likely to get caught on the tube due to the aperture268moving in a smoother path. The end of the tube could have one or more flanges, which could be a location for the aperture268to catch on. With the large radius of curvature of the path of the aperture268, the aperture268will be travelling substantially vertically as it passes over the flange(s) on the end of the tube. If the radius of curvature was smaller, the aperture268would be travelling at more of an angle as it passes over the flange(s), meaning the aperture268would be more likely to catch on the flange(s) of the tube.

Thirdly, as the upper gas port275is located further from the axis of rotation of the handle261, the upper gas port275is also located further from the handle261when the handle is lifted. This is beneficial, as the user may use the upper gas port275to pull on the filter when removing it from the housing100, and the increased distance between the upper gas port275and the handle261gives the user more room to grip the second inlet. The filter module271may have a grip feature at or near its upper surface for a user to grip to remove the filter from the housing100.

It will be appreciated that these benefits can also be obtained with a filter that only has the upper gas port275and that doesn't also have the lower gas port273or the ambient air inlets.

While the filter module271is shown as being on the left side of the housing100, it could instead be installed in filter recesses on the right side of the housing. In that configuration, the right side member of the handle261would have the aperture268. Alternatively, both sides of the housing could have filter recesses for receipt of respective filter modules271, with both sides of the handle261having the apertures268.

The handle261is pivotally mounted to the housing100by a forward end of the handle, and the filter module271is installed in the housing so that the side of the filter having the upper gas port275is positioned rearwardly on the filter module. Alternatively, a rear end of the handle261could be pivotally mounted to the housing100(so that the transverse carrying portion262is positioned toward the front of the housing100rather than towards the rear of the housing), and the filter module271could be installed in the housing so that the side of the filter having the upper gas port275is positioned forwardly on the filter module.

As described above, the filter module271is removable and may be removed by pulling on the upper gas port275, or alternatively on a grip feature. The housing may comprise a push button or a release latch.FIG.3shows a release latch in the form of a filter release tab276. The filter release tab276comprises a pivoting member that pushes the filter module271away from the housing. In the form shown, the filter release tab276pushes the filter module271upwardly and outwardly. Alternatively, the push button may dislodge the filter module271from a secured position such that the filter module271can be pulled out by hand. An alternative method of removing the filter module271is by using a filter removal tool280, which is shown inFIGS.57and58.

The filter removal tool280comprises an engagement portion281and a gripping portion282. The engagement portion281is generally cylindrical and comprises an internal recess283that corresponds to, and receives, the upper gas port275. The internal recess283is shaped to match a standard medical taper, such as the shape of the upper gas port275. The internal recess283may have a smooth surface as shown inFIG.57. Alternatively, the internal recess may comprise one or more engagement features for engaging with features on the filter portion275. For example, the inner surface of the internal recess283may comprise one or more ridges or one or more annular recesses located on an inner surface of the engagement portion281, adjacent the recess defined by the terminal lip of the engagement portion.

FIG.57shows the gripping portion282comprises a tab284having an expanded flat region285. The flat region285is configured to be manually gripped by a user, for example between the user's thumb and index finger. The expanded flat region285may also comprise a textured surface and/or one or more protrusions286configured to aid the user in gripping the filter removal tool280.

In use, the user would initially press the filter removal tool280onto the upper gas port275, such that the upper gas port275engages with the internal recess283of the engagement portion281. In order to create a tighter fit between the internal recess283and the upper gas port275, the user can twist the filter removal tool280relative to the upper gas port275as they press the tool280onto the upper gas port275, an action which is made possible by the width of the tab284. Once the filter removal tool280is engaged with the upper gas port275, the user can press on the filter release tab276(FIG.3) located on the side of the base unit50. That will allow the filter to move relative to the main housing100of the base unit50. The user can then proceed to pull the filter removal tool280away from the main housing100of the base unit50, which will in turn pull the filter module271away from the main housing100of the base unit50. If the user attempts to pull out the filter module271using the filter removal tool280without first pressing on the filter release tab, then the filter removal tool280will simply disengage from the upper gas port275without damaging the filter module271or the filter removal tool280.

If the filter removal tool280has internal ridges or recesses, twisting the filter removal tool280may cause the internal ridges or recesses to engage with the corresponding ridges or recesses on the upper gas port275of the filter module271. The engagement of the various ridges or recesses causes the tool to grip on to the upper port of the filter module271thereby making removal of the filter module271easier.

Once the filter module271is removed, the user can discard the filter removal tool280along with the filter module271, and then proceed to insert a new filter module271into the device. As the filter removal tool280may be discarded along with the filter module271, the filter removal tool280may comprise a bio-sourced and/or bio-degradable plastic in order to reduce waste. Alternatively, the filter removal tool may be made of a recyclable plastic.

The filter removal tool280is useful in situations in which the upper gas port275may be too small or awkward for some users to be grip well, thereby making it difficult to pull the filter module271out. Additionally, the filter removal tool280will only need to be assembled with the filter module271when the tool280is being used to remove the filter module271—there is no need for the tool280, or any similar other component, to protrude from the main housing100of the base unit50when not in use.

A filter removal tool280may be packaged with each filter module271. The filter removal tool280may be placed in the same packaging as the filter module271. Alternatively, the filter removal tool280may be positioned in a sealed packaging that is provided with or within the packaging of the filter module271. The filter removal tool280being sealed from the filter module271reduces the chances of contamination of the filter module271prior to the filter module271packaging being opened.

The breathing assistance apparatus has a valve module301shown inFIG.40. The valve module301controls the flow of oxygen and/or other gases entering the gas flow path of the apparatus10, and enables the apparatus10to regulate the proportion of oxygen entrained in the airflow. The valve module301is formed as a modular component for ease of manufacture, assembly, servicing, or replacement, for example in the event of malfunction, routine maintenance, or future upgrade/improvement.

The valve module301is engaged with the main housing100of the base unit50of the apparatus, such that the valve module301is substantially received in the housing and is accessible from the exterior of the housing. The valve module301may be removable from the housing100, or may not be removable. Part of the valve module301is arranged to be substantially flush with an external wall of the housing, for example the bottom wall115of the lower chassis104, when the valve module is engaged with the housing. The valve module301comprises a flow control valve303that is arranged to control a flow of gas through a valve manifold. The valve303is arranged to control a flow of gas into part of the apparatus. For example, the valve303may be arranged to control a flow of gas to the filter module271. Alternatively, the valve301may be arranged to control a flow of gas to another part of the apparatus10. The valve module301and filter module271are positioned upstream of the blower of the motor module.

The valve303receives gases from an inlet port304which, in the form shown, is embodied in a swivel connector305. The valve303delivers gases to an outlet port307. The outlet port307is configured to fluidly couple to the first inlet273of the filter module271.

The valve module301also comprises ambient air ports309to enable ambient air to be delivered to the ambient air inlets of the filter module271.

A previous configuration of the valve module is described in WO2018/074935A1 (WO '935). Unless described otherwise herein, the features and functioning of the valve module301are the same as the valve module described in WO '935, and the contents of that specification are incorporated herein in their entirety by way of reference.

The valve module301is in electrical communication with the main power board263aof the apparatus10, to allow the apparatus10to power and/or communicate with the valve module301. In WO '935, the lower chassis had a valve recess for receiving a valve module, and a battery recess for receiving the battery cover. These two recesses were separated by a wall, with a gap being provided in the wall to allow wires (or alternatively a flexible PCB) to pass from the valve module, through the battery recess, and then connect with the power board. In order to help prevent oxygen leaking from the valve recess into the battery recess, a grommet was located at the gap, with the flexible PCB being passed through the grommet.

Referring toFIGS.37to39, in the present configuration, the lower chassis104of the housing100comprises a valve recess105in its underside for receipt of the valve module301and a battery recess107in its rear side for receipt of the battery module125. The wires from the valve module301do not pass directly from the valve recess105into the battery recess107. Instead, the wires now pass from the valve recess105to the recess122for the motor module, and then from the recess122for the motor module to the battery recess107. This offers a number of advantages. The wiring path WP1is shown schematically by a broken line inFIG.37.

Firstly, any oxygen that leaks from the valve module301should be prevented from flowing into the battery recess107, as the battery recess contains a number of electrical connections, including the electrical connectors for the main power board263a. By using the proposed routing WP1for the wires, the wall between the valve recess105and the battery recess107can be left intact and impermeable to gas flow. In order for oxygen to get into the battery recess107, it would need to flow into the motor module recess122first, and then from the motor module recess122into the battery recess107. Due to the motor module recess122being unsealed, the oxygen in this scenario would disperse out of the apparatus from the motor module recess122, with only an insignificant amount of oxygen at most continuing into the battery recess107.

Secondly, as there is no gap in the wall between the valve recess105and the battery recess107, the aforementioned grommet is no longer required. This reduces the number of components and simplifies manufacturing.

Another change to the valve module301comes as a result of changes to the wiring for the heater plate141. In the previous configuration shown in FIG. 162 of WO2016/207838A9, the heater plate would connect to the upper chassis, with the wiring for the heater plate passing through a first gap in the upper chassis. After passing through this gap the wiring would be located between the upper and lower chassis (i.e. inside the housing) and connected to the power board.

In the present configuration, the heater plate140instead connects to the lower chassis104. This is beneficial, as any liquid that spills around the heater plate140can drain through gaps in the lower housing and out underneath the housing100, without having any chance of pooling between the upper chassis102and lower chassis104.

As shown schematically inFIG.38, wiring from the heater plate140exits the lower portion108aof the liquid chamber recess108, out through gap108b, along the underside of the base wall beneath the recess108, and back into the lower chassis104through a second gap108c. The wiring path WP2is shown schematically inFIG.38. The second gap108cprovides an entrance for the wiring path into an internal area of the housing100.

In order to prevent the wiring being exposed to an exterior of the apparatus10between the first gap108band the second gap108c, a cover is provided over this section of the base of the lower chassis104. Similarly, between leaving the valve recess105and entering the battery recess107, the wiring running along the wiring path WP1from the valve module301would also be exposed if it were not also provided with a cover.

The cover for these two sections is provided by a base housing member311of the valve module301, as shown inFIG.39. This enables the two sections to be covered without adding extra components to the housing100. A main body portion313of the base housing member311provides the cover for a wiring path WP1. A forwardly and laterally extending finger portion315of the base housing member311provides the cover for the wiring path WP2. The main body portion313completely surrounds the edge of the base123of the motor module (not shown inFIG.39), thereby better securing the motor module in the housing100, such that it cannot be removed, unless the valve module is301is removable from the housing and is removed first. Additionally, the size of the base housing member311allows multiple fasteners to be used to fasten the valve module301to the lower chassis104of the housing, thereby better securing the valve module301to the housing100.

The base housing member311has an overlap region317, which is designed to overlap with the rear edge of a base of the guard160. During assembly, the valve module301would be coupled with the lower chassis104, with the guard160being coupled to the lower chassis104after that. The guard160would then overlap the base housing member311of the valve module301, and prevent the valve module301from being removed without first removing the guard160from the housing. As the valve housing prevents the motor module from being removed, this also means that the guard160also indirectly prevents the motor module from being removed.

As shown inFIG.40, the valve module301also has a post319extending upwardly from a portion of the valve housing, and in the form shown from a cover plate321above the valve303. During assembly, the wires/flexible PCB from the valve module301would be wrapped around the post319. Once wrapped around the post319, any tensile force applied to the wires would cause the wires to tighten around the post, instead of becoming dislodged from the valve module301. The post may also have a hooked end319ain the form of a lateral or perpendicular protrusion at end of the post. This helps prevent the wires from sliding off the post319.

Referring toFIGS.41and42, the lower chassis104has a battery recess107, with a wall142separating the battery recess107from the recess122for receipt of the motor module. This wall has a gap143adjacent its bottom edge to allow wires301w(shown in broken lines inFIG.42) from the valve module301to pass between the two recesses. The wires301ware used to provide power and/or communication to the valve module301. Similarly, a flexible PCB123p(shown in broken lines inFIG.42) is used to provide power and/or communication to the motor module, and can also pass through this gap143. Both the flexible PCB for the motor module and the wires for the valve module301run vertically through the battery recess107along the rear surface of the wall142of the lower chassis104in order to connect with the main power board161.

The rear surface of the wall142of the lower chassis104has retaining features144designed to retain the flexible PCB. The retaining features are oriented substantially vertically and are positioned above the gap143. The retaining features have two spaced apart ribs144athat extend from the rear surface of the wall142of the lower chassis104, with inwardly facing protrusions144bextending from the terminal edges of the ribs144a. The distance between the ribs144ais configured to be complementary with the width of the flexible PCB123p. The distance between the protrusions144bis smaller than the width of the flexible PCB123p. Once assembled, the flexible PCB123pwould sit between the ribs144awith the protrusions144bretaining the flexible PCB in the desired position between the protrusions144band the wall142.

The wires301wfor the valve module301can also run between the ribs144aof the retaining features. The wires301would be placed between the flexible PCB123pand the rear surface of the wall142, such that the retaining features144retain the flexible PCB123p, with the flexible PCB retaining the wiring301w. The rear surface of the wall142of the lower chassis104can additionally have one or more grooves to further aid in retaining the wiring in the desired position.

Also located between the ribs144aare one or more supports144cextending from the wall142to support the flexible PCB. The supports144care positioned between the ribs144aand have a forward-rearward depth smaller than that of the ribs144a. The supports144csupport the flexible PCB123pat the correct distance from the rear surface of the wall142to ensure the protrusions144bof the ribs144acontact the flexible PCB.

Additionally, the side(s) of the supports144cform(s) a boundary for the track for the wires. As such, the track can be bounded on four sides during use by the rear surface of the wall142, one of the ribs144aof the retaining features, one side of one of the supports144c, and the flexible PCB123p. Alternatively, the track can be bounded on four sides during use by the rear surface of the wall142, sides of two of the supports144c(if a gap is provided between the upper ends of the two supports144c), and the flexible PCB123p. The depth of the supports144c, as well as the distance between the support144cand the rib144aare configured to create a cross-sectional area that is complementary to the wires, such that the wires are tightly packed within the track once the apparatus is fully assembled.

In an alternative configuration, the flexible PCB123pcould be used for connecting the valve module301to the main power board161, with the wires301wthen used for connecting the motor module to the main power board161. In a further alternative configuration, the motor module and the valve module301could both have a flexible PCB, with the flexible PCBs being stacked together between the retaining features144. The track for receipt of wires would not be required in this configuration.

The gap143is advantageously positioned directly vertically below the base of the retaining features144, so that that flexible PCB and wires can extend directly vertically upwardly from the gap143, through the retaining features144, and to the main power board161so as to not kink the flexible PCB and wires.

The power panel331shown inFIG.43is located directly vertically above the retaining features144. The power panel is retained between the upper chassis102and the lower chassis104, and has multiple receptacles to allow the electrical connectors to extend through the power panel. The power panel331has a slot333extending into the bottom of a rear surface of a body portion335of the power panel331.

The slot comprises a first enlarged region333aconfigured for receipt of the flexible PCB123p, and an auxiliary transversely extending smaller region333bin the form of a hooked recess for receipt of the wires301w. When assembled with the housing100, the slot333is located above the retaining features144. The upper end of the slot is in communication with a recessed portion337which extends to a receptacle339at an upper edge of the power panel331. When assembled, the receptacle339contains electrical connectors for the main power board263athat the flexible PCB and the wires will connect to. The flexible PCB and the wires extend from the retaining features144, through the slot333, and into a recessed portion337to couple with the main power board connectors in the receptacle339.

The power panel331has two tapered side walls341with projecting retention features343in the form of elongate ribs. The retention features343are received in complementary grooves in the upper chassis part102and/or lower chassis part104to mount the power panel331to the housing100.

During assembly, the rear surface of the wall142of the lower chassis104is exposed such that the flexible PCB and the wiring can easily be assembled with the retaining features144and connected to the connectors of the main power board263athat are in the receptacle339. Once this has been done, the battery module125can be connected, thereby covering the flexible PCB and the wiring. This protects the flexible PCB and the wiring, as well as helping to retain it in place.

The back walls113,142of the housing form a close fit with the battery once the battery and battery cover126are assembled to the housing100. This holds the battery in the correct position without requiring additional fasteners or adhesive. This makes assembly, maintenance, and repair more simple.

Referring toFIG.41, an electrical socket114is provided in a recess in the back of the lower chassis104, and is configured to connect a power cord to the main power board263ato power the main power board263a. The power cord removably connects to the electrical socket114, such that if the power cord becomes damaged during use it can be replaced without having to perform any rewiring of the apparatus10.

However, during typical use it would be desirable to prevent the power cord from being disconnected from the base unit50of the apparatus10. Firstly, this would prevent the power cord from accidentally being disconnected such that the apparatus10loses mains power. Secondly, this prevents the power cord from being separated from the base unit50of the apparatus10and potentially being misplaced.

In order to prevent the power cord from being removed from the base unit of the apparatus10, a power cord retainer351as shown inFIGS.45to51is used. In one configuration, the power cord retainer351connects to a battery cover126of the battery module125, such that during assembly the power cord would be attached to the base unit50of the apparatus10after the battery cover126, with the power cord retainer351being attached last. Alternatively, the power cord retainer351could be connected to a different part of the housing100, such as directly to the lower chassis104for example.

Referring toFIGS.48aand48b, the battery cover126comprises a receptacle housing126afor receipt of the battery module125, fastener apertures126bfor receipt of fasteners to mount the battery cover126to the lower chassis104, upper retention features126cto interact with complementary mounting features on the lower chassis104or upper chassis102, and a retainer cavity126dfor receipt of the power cord retainer351.

Referring toFIGS.45,46,48A, and48B, the power cord retainer351comprises an inverted substantially U-shaped body portion353, with an upper transverse cross-member355, a right side downwardly extending leg357, and a left side downwardly extending leg359(with the left and right sides viewed from the front of the apparatus10in use). The body portion353comprises a relatively narrow and tall forward body portion361having an upwardly extending upper flange363corresponding to the upper transverse cross-member355. The body portion353further comprises a relatively wide and short rearward body portion365having a right side outer flange367corresponding to the right side leg and a left side outer flange369corresponding to the left side leg. The left side leg is further provided with a left side inner flange371that is defined by a wedge portion having an upper narrow end and lower wide end. A vertical channel373is provided between the left side outer flange369and the left side inner flange371.

A power cord passage375is provided between the right side leg357and the left side leg359. The upper part375aof the passage375is wider than the lower part375bof the passage375.

Forwardly projecting prongs377are provided in an upper section of the body, above the upper part375aof the power cord passage.

Referring toFIGS.48A and48B, the power cord retainer351is mounted to the housing100by moving the power cord retainer vertically upwardly relative to the lower chassis104and battery cover126. The upper flange363of the power cord retainer abuts an upper horizontal lip126eof the cavity126dof the battery cover. This lip126ehelps retain the power cord retainer in position. A vertical rib126fextends downwardly from the lip126eand abuts the left side outer flange369of the power cord retainer351to aid the user in correctly aligning the upper flange363with the lip126e. Once fully inserted, the left side inner flange371also abuts the vertical rib126fsuch that the vertical rib126fis located in the channel373between the left side inner and outer flanges371,369, further retaining the power cord retainer351in the correct position.

A foot376extends forwardly from the lower end of the right side leg357and has a fastener-receiving aperture376athat aligns with, and is complementary to, a fastener-receiving aperture126ein the cavity126dof the battery cover126when the power cord retainer is fully inserted into the cavity126d. Once assembled, a fastener, such as a screw, can be inserted through the apertures376a,126gto fasten the power cord retainer351to the battery cover126. This assembly is designed such that the power cord retainer351, and in turn the power cord, are unable to be removed except by a technician.

In the assembled configuration, the prongs377of the power cord retainer engage with electrical connecter of the power cord in order to hold it in engagement with the electrical connecter114of the apparatus10. The prongs377have a gap between them that allows the cord itself to pass through but not the electrical connector of the power cord. The cord is then passed through the power cord passage375.

The power cord retainer351is also shown as having a clip378. In the form shown, the clip378is on an upper part of the body353above the power cord passage375. The clip378can be used to help retain one or more cables. One side of the clip may be open to enable cable(s) to be inserted into the clip.

For example, as shown inFIG.43, the power panel331can also have additional receptacles344for additional electrical connecters (such as USB connections) located above the electrical connecter114for the power cord. When cables are connected to these electrical connectors in the receptacles344, the cables can be attached to or received in the clip378to help prevent the cable from accidently being dislodged from the receptacles344.

FIGS.52to56show an alternative configuration of the removable component comprising a removable elbow1171. Unless described differently below, the features, functioning, and options of the removable elbow1171are the same as for removable elbow171, and like reference numerals indicate like parts with the addition of 1000.

Although it is not shown inFIGS.52-56, the removable elbow1171will have one or more seals173or sealing elements175on the recess1163b, as described above.

As discussed above in relation to removable elbow171, the removable elbow1171also includes an electrical connection. The elbow1171has an inlet for pneumatically connecting to a first accessory for the breathing assistance apparatus10, such as the liquid chamber151, an outlet for pneumatically and optionally electrically connecting to a second accessory for the breathing assistance apparatus, such as the patient conduit16, and a printed circuit board (PCB) electrical connector1178for electrically connecting to the breathing assistance apparatus10to form an electrical connection with an electrical component in the housing100. The electrical connector1178provides an electrical link between the base unit50of the apparatus10and the temperature sensors1176embedded in the elbow1171, as well as between the base unit50of the apparatus10and the conduit16(when the conduit has one or more sensors and/or a heating element), via the electrical interconnecting assembly221in the housing which is described above. The PCB electrical connector1178electrically connects to the electrical interconnecting assembly221when the removable elbow1171is connected to the housing100.

The pneumatic inlet connection of the removable elbow1171is provided by the humidified gas inlet port1163, the pneumatic outlet connection is provided by the patient outlet port1030, and the outlet electrical connection is provided by connectors1179that are provided in the chimney1179athat extends upwardly parallel to an axis of the port1030.

The humidified gas inlet port1163and the patient outlet port1030are in fluid communication with each other via a gas flow path in the removable elbow. Electrical connectors1178,1179of the removable elbow are pneumatically isolated from the gas flow path between the humidified gas inlet port1163and the patient outlet port1030, via at least one wall of the removable elbow. For example, the body of the removable elbow may be injection moulded plastic material, with isolated regions provided for the electrical connectors that are separate and isolated from the gas flow path.

Because the portion of the removable elbow, namely PCB electrical connector1178, that is configured to form the electrical connection with the electrical component in the housing (the electrical interconnecting assembly221) is pneumatically isolated from the gas flow path of the removable elbow, coupling the removable component to the housing solely provides an electrical connection between the PCB electrical connector1178and the electrical interconnecting assembly221. It does not form a direct pneumatic connection between the gas flow path in the removable elbow1171and the housing100. Instead, the gas flow path in the removable elbow provides a pneumatic connection between the first accessory (the liquid chamber151) and the second accessory (the patent conduit30).

In the configuration shown, the PCB electrical connector178is partly housed in a housing1178athat is integrally formed with the elbow. The PCB electrical connector1178projects rearwardly from the housing1178ato insert into an electrical connector on the base unit50of the apparatus10in a horizontal direction (i.e. the same rearward insertion direction CID in which the liquid chamber151connects to the housing100of the base unit50and the same rearward direction RD in which the shroud190connects to the screen carrier211). As such, the removable elbow1171can be horizontally connected to the apparatus in the rearward direction RD, with the liquid chamber151being horizontally connected to the two apparatus ports161,163after that. Alternatively, the liquid chamber151can initially be connected to the removable elbow1171, with the assembled liquid chamber151and elbow171then being connected to the base unit50of the apparatus together by moving them in the rearward direction together.

As shown inFIGS.28to36, the PCB electrical connector1178of the removable elbow171inserts into an electrical interconnecting assembly221of the base unit50of the apparatus10. The interconnecting assembly221is made up of three components; the socket231, the PCB241, and the overmould251.

As explained above in relation toFIGS.29and30, the socket231comprises a housing232that defines a receptacle233to receive the PCB electrical connector1178of the removable elbow1171. A forward portion233aof the receptacle22has relatively large vertical and horizontal dimensions to receive the housing1178aof the electrical connector. A rear portion233bof the receptacle233has relatively small vertical and horizontal dimensions to receive the portion of the PCB electrical connector1178that projects rearwardly from the housing1178a. The rear portion233bis defined between upper and lower ribs234that extend into the rear part of the receptacle from upper and lower walls thereof. The rear portion233bof the receptacle is configured to form a close or tight fit with the PCB electrical connector1178to assist with holding the removable elbow1171in connection with the socket231. The forward portion233aof the receptacle may be configured to form a close or tight fit with the housing1178aof the PCB electrical connector178to assist with holding the removable elbow1171in connection with the socket231. Alternatively, that may form a looser fit.

The housing1178aof the removable elbow1171carries a seal1182. The seal1182is configured to engage against the inner surface of the forward portion233aof the receptacle233of the socket231when the removable elbow1171is engaged with the electrical interconnecting assembly221of the base unit50of the apparatus. The seal1182provides a pneumatic and/or liquid seal between the housing1178aof the removable elbow1171and the receptacle233of the socket231.

The seal1182prevents or reduces breathing gas leak and/or condensate from moving toward the electronics in the removable elbow1171and the electrical connector1178of the elbow.

The housing1178aof the removable elbow1171comprises a generally annular recess1178bthat extends around the top, sides, and at least part of the bottom of the housing1178a. The seal1182is received in the annular recess1178b, and projects outwardly beyond adjacent surfaces of the housing1178ato engage with the inner surface of the forward portion233aof the receptacle233of the electrical interconnecting assembly221.

The seal1182may be a wiper seal. The wiper seal may have a T-shaped cross-section. In the form shown, the wiper seal is a flexible annular rim that runs around the circumference of the housing1178a. The wiper seal may or may not have a bulbous tip on the seal.

In alternative configurations, the seal1182may be an L-seal, X-ring, or O-ring.

The seal1182may have a single sealing element as shown. Alternatively, the seal1182may have a plurality of sealing elements as described in relation to seal173and sealing elements175. Alternatively, the housing may carry a plurality of seals1182. Each of the plurality of seals1182may have a single sealing element.

The seal1182may be made from silicone rubber. In an alternative configuration, the seal1182could be made from any suitable elastomer, such as polyurethane. Alternatively, the seal1182may be made from thermoplastic elastomer(s) and/or thermoplastic vulcanisate(s), particularly if the seal will be overmoulded onto the removable elbow.

A bottom portion of the housing1178acomprises a cavity1178cfor receipt of the PCB electrical connector1178. In the form shown, the cavity1178cis open to the bottom of the housing and to the distal, rear end of the housing.

The housing comprises one or more engagement features1178dto assist with locating the PCB electrical connector1178in the cavity1178cof the housing.

In the form shown, the engagement features1178dcomprise one or more downwardly directed projections. The projection(s) is/are configured to extend through complementary aperture(s) in the PCB electrical connector1178.

The engagement feature(s)1178dmay comprise enlarged head(s) to reduce the likelihood of the PCB electrical connector1178disconnecting from the engagement features1178d. The enlarged head(s) may be tapered so that a lower end of the head has a smaller transverse diameter than an upper end of the head, to enable the PCB electrical connector to be inserted into the cavity1178cover the heads.

While two engagement features1178dare shown, a single engagement feature1178dor three or more engagement features1178dmay be provided.

During an initial stage of assembly of the removable elbow1171(FIG.54), the removable elbow does not have the PCB electrical connector in the cavity1187cof the housing1178a.

The PCB electrical connector1178is then inserted into the cavity1178cof the housing1178a, with the engagement feature(s)1178dextending through complementary aperture(s) in the PCB electrical connector. The PCB electrical connector1178is partly housed in the cavity1178cof the housing1178aand projects rearwardly from the housing1178a.

The seal1182is then overmoulded onto the housing1178a.

As shown inFIG.56, the overmoulded component comprises a moulded base member1182athat is configured to substantially fill the cavity1178cand cover the underside of the part of the PCB electrical connector1178that is housed in the cavity, and the integrally moulded seal1182. The moulded base member1182aassists with retaining the PCB electrical connector1178in the housing1178a.

In an alternative configuration, the seal1182may be separately formed and stretched onto the recess1178bof the housing1178a. Alternatively, the seal1182may be overmoulded onto the recess of the housing, but the overmoulding may not comprise the integrally formed base member1182a. The base member1182amay be separately formed or may not be present.

One or more tactile features1172care provided on an upper surface of the flat horizontal tab1172. In the form shown, the tactile features comprise a plurality of raised features extending upwardly from the upper surface of the tab1172. The tactile features may comprise a plurality of transverse ribs as shown, but could have any suitable other configuration such as upstanding protrusions that could be circular or any other suitable shape.

The tactile feature(s)1172cassist with a user gripping the tab to pull the removable elbow1171out of engagement from the recess199in the shroud190, to remove the removable elbow1171from the housing100of the breathing assistance apparatus base unit50.

The tactile feature(s)1172ccould alternatively be provided on the removable elbow171described above.

As shown inFIGS.52and53, the removable elbow has a flange1172dthat is positioned below a portion of body of the elbow that provides the flat horizontal tab1172. The flange1172dis spaced apart from the underside of the rear portion of the tab1172by a space1172e.

In the form shown, the shape of the flange1172dcorresponds substantially to the shape of the portion of the body above the space1172e, and has a relatively wide forward region adjacent the patient outlet port1030and a relatively narrow rear region adjacent the chimney1179a. Different shapes could be provided.

At least a portion of the flange1172dhas a larger dimension than the corresponding portion of the recess199of the shroud.

In the form shown, the width of at least the relatively narrow rear region of the flange1172dis larger than the corresponding contoured tapering rear wall region199cof the shroud190(FIG.14). Additionally, or alternatively, the width of the relatively wide forward region of the flange1172dmay be wider than a corresponding relatively wide forward region of the recess199of the shroud.

The flange1172dforms a close fit with the underside of a portion of the shroud when the removable elbow1171is connected to the base unit50.

The purpose of this is to resist any upward forces placed on the removable elbow (such as when the patient breathing conduit16is being removed from the patient outlet port1130), thereby preventing stress from being placed on the flexible tab1172and the electrical connector1178.

In different configurations, the removable component1171may not have an elbow shape, and could instead, for example, have aligned inlet and outlet ports.

Details of a previous configuration of the motor module are disclosed WO2016/207838A9 (WO'838). The contents of that specification are incorporated herein in their entirety by way of reference. In particular, WO '838 discloses the motor module comprising a sensing layer and comprising three main components; a base1403, a cover layer1440, and a sensing layer1420sandwiched between the base1403and the cover layer1440. Those components are shown inFIG.59.

The motor module has a sealed air or gas flow path between the base1403and the cover layer1440, such that gases are prevented from escaping and moving towards the electronics of the breathing assistance apparatus. In that configuration, the seal used could be a soft seal such as an O-ring. These types of seals would typically rely on a compressive force generated by the fasteners that retain the three layers of the motor module together. That configuration uses two soft seals; one for sealing between the upper surface of the base1403and the lower surface of sensing layer1420, and one for sealing between the lower surface of the cover layer1440and the upper surface of the sensing layer1420. Each seal is located in a groove located on either the sensing layer1420or the base1403or the cover layer1440in order properly position and retain the seals. Alternatively, the seals may be overmoulded onto one layer and the other layer is positioned on top of the layer including the overmoulded seal to sandwich the seal.

The electronics of the breathing assistance apparatus are positioned in the low pressure region of the main housing of the apparatus to cause a tortuous path which decreases the likelihood of liquid or oxygen ingress to the electronics. The portion of the PCB1456A comprising the electronics components is positioned ‘outside’ the seals—that is, it is outside the bulk gas flow. The portion of the PCB1456comprising the sensors is inside the flow path and is sealed from the outside by the seals pressing tightly against the PCB1456. Therefore, liquid or oxygen ingress may be at least substantially prevented.

The cover layer1440may be coupled to the gas flow path and sensing layer1420using fasteners such as screws. The fasteners sandwich the two sections together providing a compressive force to seal the seals2423,2443against the PCB board1456. Any suitable number of apertures may be provided for receipt of the screws. Washers could be used on the underside of the screws. To minimise the chance of leakage around the screws to the low pressure region (which could impact performance), ridges could be added to the bosses on which the head of the screw will sit once inserted. Alternatively, once the screws have been inserted, adhesive or filler could be used to seal any possible openings. Alternatively, the cover layer1440could comprise clips or adhesive features to couple with the gas flow path and sensing layer1420to seal between the layers when force is applied.

Features of an alternative seal to the soft seals will now be described.

As shown inFIGS.60and61, an upper side of the body1422of the sensing layer1420is provided with a groove1423for receipt of a seal2423(described in more detail below) to seal against an underside of the PCB1456. The seal2423also seals against an underside of the cover layer1440. A lower side of the body1442of the cover layer1440is provided with a groove1443for receipt of a seal2443(also described in more detail below) to seal against the upper side of the PCB1456.

FIG.62is a schematic of a groove1423/1443retaining a seal2423/2443. The grooves1423,1443are advantageously provided with inwardly-directed projections1423B,1443B (shown more clearly inFIG.62A) to assist with maintaining the seals2423,2443in position in the grooves.

The seals2423,2443seal the high pressure region of the motor module, as gasses passing through the gas flow path have been pressurised by the blower. The seals2423,2443prevent gases from escaping and moving towards the electronics of the apparatus. The seals2423,2443also prevent fluid ingress, for example, if there is condensation on the sensing board, the condensation is prevented from coming into the gases flow.

As shown inFIG.65, each seal2423,2443has a fixed portion2424and a flexible portion2425. With reference toFIG.65, the fixed portion2424is shaped to conform to the groove1423,1443that retains the seal. The lower region of the seal may have tapered sides2431to fit into the groove1423,1443and create a friction fit. The tapered sides are shown inFIG.65. The groove may be a groove1423in the base1403or a groove1443in the cover layer1440for example. The lower part of the seal2423is a similar size and shape as the size and shape of the groove1423. Once the seal2423is assembled with the base1403, the fixed portion will be secured in the groove1423and remain stationary relative to the base1403.

With reference toFIG.65, the flexible portion2425of the seal is structured to curve or angle towards one side whilst in the unflexed position. The flexible portion has a generally concave kinked surface2426formed by two flat surfaces2427that meet at a corner2428. The flexible portion also has a convex curved surface2429, which together with the generally concave surface2426, gives the flexible portion2425a curved shape. This curved shape causes the flexible portion2425of the seal to flex towards one side when the seal engages with the sealing surface of the sensing layer1420. In the orientation ofFIG.65, the flexible portion flexes to the right side. In particular, the flexible portion2425is structured such that it curves or angles inwardly towards the gas flow path.

The described shape extends around the entire seal2423,2443.

The flexible portion2425is configured to flex when a compressive force is applied at or near a free end2430of the flexible portion2425in a direction towards the fixed portion2424. Such a compressive force is applied when the flexible portion2425is pressed against an opposing sealing surface. Once the seal2423is assembled with the base1403, the flexible portion2425is able to flex relative to the fixed portion2424and the base1403. The flexible portion2425preferably flexes resiliently—that is, the flexible portion2425is biased to return to its at rest position or unflexed position after the compressive force is removed. The biasing force results in a sealing force against the sensing layer1420when the contact with the sensing layer1420forces the flexible portion2425into a flexed position. When moving from the unflexed position to the flexed position, the flexible portion2425bends to have a more curved shape than its at rest shape. The free end2430moves inwardly and downwardly into the more curved flexed position. In particular, the flexible portion2425bends inwardly towards the gas flow path.

Additionally or alternatively to curving, the flexible portion2425can flex or bend about the corner2428. The corner2428may be a fold line to assist with folding the seal. The upper flat surface2427contacts the opposing flat top surface of the fixed portion2424to form the operative seal. In the operative configuration, the flexible portion2425and the fixed portion form a closed shape with the upper flat surface2427pressed against the opposing flat top surface of the fixed portion2424. Alternatively, the upper flat surface2427may simply rest on the opposing flat top surface. Because the flexible portion2425is flexed to contact a portion of the fixed portion2424, the seal forms a tortuous path for any gases to travel through when the seal is in the operative position or orientation.

The description above refers to the orientation of the seal that is assembled with the base1403. The orientation of the seal will depend on the groove that the seal is assembled with. The seal that is assembled with the cover layer1440is upside down compared to the seal that is assembled with the base1403. That is, the fixed portion2424is above the flexible portion2425.

An advantage of a seal having a flexible portion2425compared with a compressive seal is that a lower force is required for an adequate seal to be produced between the base1403and the sensing layer1420, and/or between the sensing layer1420and the cover layer1440. Additionally, the seal would produce adequate sealing contact between the components in a wider range of positions. As a result, the seal allows for a greater tolerance of the components. For example, there is a greater tolerance for in the event of flexing of the components and/or manufacturing variation.

A further advantage of such a configuration is that any increase in pressure in the gas flow path would result in the flexible portion2425of the seal being further biased into the unflexed position. As a result, an increase in pressure in the air path would simply increase the sealing force between the flexible portion2425and the sealing surface of the sensing layer1420. As such, there is a reduced chance of a large pressure resulting in the seal failing.

In use, the flexible portion2425together with the fixed portion2424form a seal with double/overlapping portions with an air gap in between those portions. If there is a leak of gas from the gas flow path, the gas flow needs to follow tortuous path around the flexible and fixed portions, including crossing the gap between those portions. The tortuous path is due to the curved flexible portion2425. If there is a leak, any leaked gases have to follow a tortuous path around and through the flexed seal.

The seal is, or comprises, an elastomeric material. The seal preferably comprises a material that exhibits a low amount of material creep (cold flow) over time. Silicone is an example of a material with low material creep. Alternatively, the seal is, or comprises, an elastomeric thermoplastic. One or both seals could be overmoulded into the grooves of the base1403and/or cover layer1440. Alternatively, one or both seals could be formed separately and then subsequently fitted into the corresponding groove1423,1443.

FIGS.63and64show each seal having a tab2435,2445for assembly and disassembly of the seal with the cover layer or base.FIG.63also shows a plurality of integral washers2437for sealing around the fasteners that connect the base1403and cover layer1440.

One advantage of this seal2423,2443is it requires a lower compressive force to provide an adequate seal compared to soft seals. In order to achieve the required force when soft seals ae used, the fasteners need to be sufficiently spaced around the sealing region, as slight flexing of the components could cause a portion of the soft seal that is sufficiently spaced from the nearest fastener to fail in producing an adequate seal.

Additionally, the seal is less susceptible to failure if the pressure in the gas flow path reaches a certain threshold. As described above, the configuration of the flexed seal creates a tortuous path.

In WO '838, a seal may be formed between an upper edge of a filter housing of a lower chassis3202′ and a corresponding aperture in an upper chassis3102′. This seal can be produced by a tongue and groove arrangement. Unless described otherwise herein, the features and functioning of the filter housing/receptacle are the same as the filter housing/receptacle described in WO '838, and the contents of that specification are incorporated herein in their entirety by way of reference.

In the present configuration, an alternative to the tongue and groove arrangement is provided. In the present configuration, the upper chassis3102′ and lower chassis3202′ of the main housing100of the base unit50are configured such that when they are assembled together, a cavity6701is present between an upper surface of the lower chassis3202′ and a lower surface of the upper chassis3102′, as shown inFIG.67.

A seal6703is placed between these two surfaces, thereby blocking the ingress of gases into the space between the upper and lower chassis.

The seal6703has the form shown inFIG.67and the cross-section shown inFIGS.68A and68B.

The general shape of the seal6703is a shape that corresponds substantially to the shape of the body of the filter271. The transverse shape and dimensions of the seal corresponds to the shape and dimensions of the cavity6701.

FIGS.68A and68Bare cross-sectional views of the seal ofFIG.66in non-compressed and compressed states. The seal6703would initially be in a non-folded state as shown inFIG.68A. In this state, the vertical dimension of the seal6703would exceed the vertical dimension of the cavity6701. During assembly the upper surface6705of the seal would sealingly contact the lower surface6704of the upper chassis3102′, and the lower surface6707of the seal would sealingly contact the upper surface6706of the lower chassis3202′.

As shown inFIGS.68A and68B, the seal6703has an undulating shape with peaks and troughs. The seal6703has a substantially horizontal upper portion6709and a substantially horizontal lower portion6711. A first inner portion6713extends at an angle inwardly and downwardly from the left side of the upper portion6709, forming a bend6710. A second inner portion6715extends at an angle inwardly and upwardly from the left side of the lower portion6711forming a bend6712. The first inner portion6713and the second inner portion6715met at the inner side (right side ofFIGS.67aand67b) of the seal forming bend6716. The upper portion, lower portion, and inner portions form a sideways M-shaped seal. The seal6703is symmetrical about a horizontal centre line. This symmetry advantageously ensures that the seal6703deforms evenly when a vertical force is applied. Additionally, the sideways M-shape allows the seal6703to bend in the central region whilst the upper and lower surfaces of the seal remain substantially horizontal. In an alternative configuration, the seal6703may have fewer bends and/or fewer inner portions, such as a Z shape. In a further alternative configuration, the seal6703may have more bends or inner portions.

Once assembled, the contact described above would cause the seal6703to deform into a folded position. The seal would deform via a folding motion instead of simply compressing. As such, the seal6703is capable of a greater range of motion resulting from the same force when compared with a typical compressive seal. This allows the seal6703to be able to conform to the shape of the cavity6701even in the event of significant variations resulting from flexing of the components, manufacturing variation, and the like.

When compressed from the orientation inFIG.68Ato the compressed orientation inFIG.68B, the portions of the seal flex or fold such that the upper portion6709and the lower portion6711move closer together. The upper surface6705and lower surface6707form sealing surface that seal the filter to prevent pressurised gases from leaking out of the filter module271and into the housing of the main control and power circuit boards. The biasing force from the central undulating shape creates a seal.

The seal6703is manufactured from an elastomeric material. The seal6703is manufactured from silicone, which exhibits low amounts of material creep (cold flow) over time. Alternatively, the material may be manufactured from an elastomeric thermoplastic.

This cavity6701is located at a substantial distance from the fasteners that secure the lower chassis3202′ to the upper chassis3102′. As such, variations in the components or misalignments between the components could result in a leak at the cavity6701. A seal6703having the features and functions described herein allows for variations while still providing a sealing function.

Although the present disclosure has been described in terms of certain embodiments, other embodiments apparent to those of ordinary skill in the art also are within the scope of this disclosure. Thus, various changes and modifications may be made without departing from the spirit and scope of the disclosure. For instance, various components may be repositioned as desired. Features from any of the described embodiments may be combined with each other and/or an apparatus may comprise one, more, or all of the features of the above described embodiments. Moreover, not all of the features, aspects and advantages are necessarily required to practice the present disclosure. Accordingly, the scope of the present disclosure is intended to be defined only by the claims that follow.

The various configurations described are exemplary configurations only. Any one or more features from any of the configurations may be used in combination with any one or more features from any of the other configurations.

The features are described with reference to a breathing assistance apparatus that can deliver heated and humidified gases to a patient or user. The apparatus may be suitable for treating chronic obstructive pulmonary disease (COPD). The apparatus may be configured to deliver gases to a patient interface at a high flow rate (high flow therapy), particularly nasal high flow therapy.

Alternatively, the features may be used with an apparatus for a different purpose. The apparatus may be a high flow therapy apparatus, or may be a low flow therapy apparatus. For example, the features may be provided in an apparatus for providing continuous positive airway pressure (CPAP), which may deliver gases (humidified or otherwise) at lower flow rates, or may be provided in a medical insufflation apparatus.

The features could be used in a stand-alone humidifier. The standalone humidifier may have a housing, a recess108for receipt of the liquid chamber151, and a heater plate140, but may not have a motor unit. The standalone humidifier may receive gases from an external source.

Accordingly, an alternative form breathing assistance apparatus10may be a standalone humidifier apparatus comprising a base unit50defining a main housing and a humidifier12.

The standalone humidifier apparatus can deliver heated and humidified gases for various medical procedures, including respiratory therapy, laparoscopy, and the like. These apparatuses can be configured to control temperature and/or humidity. The apparatuses can also include medical circuits comprising various components that can be used to transport heated and/or humidified gases to and/or from patients. For example, in some breathing circuits, gases inhaled by a patient are delivered from a heater-humidifier through an inspiratory tube or conduit. As another example, tubes can deliver humidified gas (commonly CO2) into the abdominal cavity in insufflation circuits. This can help prevent desiccation or ‘drying out’ of the patient's internal organs, and can decrease the amount of time needed for recovery from surgery. Heater wires may extend inside of at least a portion of the tubing forming the circuit to prevent or at least reduce the likelihood of the formation of significant condensation.

A standalone humidifier apparatus would typically include a base unit50and a humidifier liquid chamber151. The base unit50can comprise a heater plate140. The liquid chamber151can be configured to hold a volume of a liquid, such as water. The heater plate can be configured to heat the volume of liquid held within the liquid chamber151to produce vapour.

The liquid chamber151is removable from the base unit to allow the liquid chamber to be more readily sterilized or disposed, or to re-fill the chamber with liquid. The body of the liquid chamber151can be formed from a non-conductive glass or plastics material but the liquid chamber can also include conductive components. For instance, the liquid chamber can include a highly heat-conductive base (for example, an aluminum base) contacting or associated with the heater plate on the heater base.

The base unit can also include electronic controls such as a master controller. In response to user-set humidity or temperature values input via a user interface and other inputs, the master controller determines when (or to what level) to energize the heater plate140to heat the liquid within the liquid chamber151.

The standalone humidifier apparatus can include a flow generator to deliver gases to the liquid chamber. In some configurations, the flow generator can comprise a ventilator, blower, or any other suitable source of pressurized gases suitable for breathing or use in medical procedures. The flow generator may be positioned in the base unit50.

Alternatively, the standalone humidifier apparatus may comprise just the base unit50and the liquid chamber151, and may be used with a separate or remote flow generator. The base unit50may be configured to fluidly connect to the separate or remote flow generator.

Therefore, the flow generator that is used with a standalone humidifier apparatus may be a wall gases source, ventilator, blower, or gas tank for example.

A standalone humidifier apparatus can be used with breathing therapies, positive pressure apparatus, noninvasive ventilation, surgical procedures including but not limited to laparoscopy, and the like. Desirably, the humidifier apparatus can be adapted to supply humidity or vapour to a supply of gases. The humidifier apparatus can be used with continuous, variable, or bi-level PAP systems or other form of respiratory therapy. In some configurations, the humidifier apparatus can be integrated into a system that delivers any such types of therapy.

An exemplary standalone humidifier apparatus is described in WO 2015/038013. The contents of that specification are incorporated herein in their entirety by way of reference.

The standalone humidifier apparatus may have any one or more of the features described or shown herein.

Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

Where reference is used herein to directional terms such as ‘up’, ‘down’, ‘forward’, ‘rearward’, ‘horizontal’, ‘vertical’ etc, those terms refer to when the apparatus is in a typical in-use position and/or with reference to particular orientations shown in the figures, and are used to show and/or describe relative directions or orientations.