Patent Description:
Respiratory apparatuses commonly have the ability to alter the humidity of the breathable gas in order to reduce drying of the patient's airway and consequent patient discomfort and associated complications. The use of a humidifier placed between the flow generator and the patient mask produces humidified gas that minimizes drying of the nasal mucosa and increases patient airway comfort. In addition in cooler climates, warm air applied generally to the face area in and about the mask is more comfortable than cold air.

Many humidifier types are available, although the most convenient form is one that is either integrated with or configured to be coupled to the relevant respiratory apparatus. While passive humidifiers can provide some relief, generally a heated humidifier is required to provide sufficient humidity and temperature to the air so that the patient will be comfortable. Humidifiers typically comprise a water tub having a capacity of several hundred milliliters, a heating element for heating the water in the tub, a control to enable the level of humidification to be varied, a gas inlet to receive gas from the flow generator, and a gas outlet adapted to be connected to a patient conduit that delivers the humidified gas to the patient's mask.

Typically, the heating element is incorporated in a heater plate which sits under, and is in thermal contact with, the water tub.

<CIT> describes a blower unit for use as part of an integrated blower/ humidification system. A humidifier comprising a humidifier chamber and a tub is disclosed, the tub being configured to contain a supply of water and being insertable into the humidifier chamber, the humidifier further comprising a humidifier lid movable between an open position in which the tub is insertable from the top into the humidifier chamber and a closed position in which the humidifier lid covers the inserted tub, the humidifier chamber further comprising an inlet configured to receive the flow of breathable gas generated by the blower unit and a bottom with a heating plate configured to heat the supply of water contained in the tub, wherein the tub comprises a tub base and a tub lid.

<CIT> relates to a pressure support system that comprises a patient circuit, a docking assemly, and a tank.

The scope of the ivention is as defined by the appended claims.

One aspect of the technology is a respiratory apparatus that comprises a humidifier for humidifying a flow of breathable gas to be delivered to a patient in which a tub of the humidifier is insulated to reduce the temperature of the water and the power consumed by the apparatus.

Another aspect of the technology is a humidifier for a respiratory apparatus that includes a chamber that is pressurizable to reduce the pressure on joints of the humidifier tub to reduce leaks.

A further aspect of the technology is a humidifier for a respiratory apparatus that includes a chamber that is pressurizable to reduce tolerances for insertion of a tub with respect to seals on an inlet and an outlet tube of the humidifier chamber.

A still further aspect of the technology is a humidifier for a respiratory apparatus that directs air over the surface of a supply of water contained in a tub to humidify a flow of breathable gas regardless of the water level.

Another aspect of the technology is a humidifier for a respiratory apparatus that includes seals that are not under the supply of water, thus reducing a risk of leakage.

A still further aspect of the technology is a humidifier for a respiratory apparatus that prevents water from spilling back into a flow generator, or blower, that generates a flow of breathable gas.

Yet another aspect of the technology is a humidifier for a respiratory apparatus that includes a tub that is disposable.

Another aspect of the technology is a humidifier for a respiratory apparatus that includes a tub that is cleanable and/or reusable.

Still another aspect of the technology is a humidifier for a respiratory apparatus that includes a tub that comprises a water level indicator, for example a water level indicator that indicates a maximum fill level. Yet another aspect of the technology relates to a water level indicator that may be removable from the tub. A still further aspect of the technology relates to a water level indicator in a tub that may be viewed through a window of the humidifier. An even further aspect of the technology relates to a water level indicator that appears to change color as the water level changes, for example appears to be a darker color or mixture of colors.

Another aspect of the technology is a humidifier for a respiratory apparatus that is connectable to a heated or non-heated tube for delivery of the humidified flow to a patient.

A further aspect of the technology relates to a tub that is removable from the humidifier and is configured to prevent any water flowing out of the tub from flowing back into the flow generator.

According to a sample embodiment, a humidifier for humidifying a flow of breathable gas to be delivered to a patient comprises a chamber configured to receive the flow of breathable gas; a tub configured to contain a supply of water, the tub being configured to be inserted into the chamber; a lid provided on the chamber and being movable between an open position and a closed position; and a seal provided on the lid, the seal being configured to seal the chamber such that the flow of breathable gas pressurizes the chamber.

According to yet another sample embodiment, a tub for insertion into a humidifier chamber comprises a tub base configured to contain a supply of water; a tub lid; a flow plate; and a seal connected to the flow plate, wherein the flow plate is positioned between the tub base and the tub lid via the engagement of the seal with side wall edges of the tub base and side wall edges of the tub lid.

According to a further sample embodiment, a respiratory apparatus for providing a humidified flow of breathable gas to a patient comprises a flow generator to generate a flow of breathable gas and a humidifier and/or a tub as described above.

According to another sample embodiment, a humidifier for humidifying a flow of breathable gas to be delivered to a patient comprises a chamber configured to receive the flow of breathable gas; a tub configured to contain a supply of water, the tub being configured to be inserted into the chamber; and a lid provided on the chamber and being movable between an open position and a closed position. The tub comprises a tub base configured to contain a supply of water; a tub lid; and a flow plate provided between the tub base and the tub lid, wherein the flow plate comprises a water level indicator configured to indicate a level of the supply of water in the tub base.

According to a still further sample embodiment, a tub is configured to contain a supply of water and to be inserted into a chamber of a humidifier. The tub comprises a tub base configured to contain a supply of water; a tub lid; and a flow plate provided between the tub base and the tub lid, wherein the flow plate comprises a water level indicator configured to indicate a level of the supply of water in the tub base. The water level indicator comprises a generally rectangular portion and a generally triangular portion. The generally triangular portion comprises an angled wall that extends at least partially below the flow plate and the angled wall comprises a drain hole and indicia.

Embodiments of the technology will now be described with reference to the accompanying drawings, in which:.

Referring to <FIG>, a respiratory apparatus <NUM> comprises a flow generator, or blower, <NUM> and a humidifier <NUM>. The humidifier <NUM> comprises a humidifier chamber <NUM> and a lid <NUM> which is pivotable between an open and a closed position. A water chamber, or tub, <NUM> is provided in the humidifier chamber <NUM> and is covered by the lid <NUM> when the lid <NUM> is in the closed position. A seal <NUM> is provided to the lid <NUM>, as shown in more detail in <FIG>. The lid <NUM> includes a window <NUM> to allow visual inspection of the contents of the humidifier tub <NUM>. The seal <NUM> includes an aperture <NUM> that corresponds to the position of the window <NUM> of the lid <NUM>.

The tub <NUM> comprises a tub lid <NUM> that is configured to direct a flow of breathable gas generated by the flow generator <NUM> along a channel <NUM> and through an outlet <NUM> of the channel <NUM> into the tub <NUM>, as described in more detail below. The tub <NUM> includes an outlet <NUM> for the humidified flow of breathable gas to a tube configured to deliver the humidified flow to a patient interface, e.g. a mask.

As shown in <FIG>, the humidifier <NUM> is connectable to the flow generator <NUM> by connectors, or latches, <NUM>. The latches <NUM> may be, for example, spring biased latches that engage corresponding recesses (not shown) in the flow generator <NUM>. An electrical connector <NUM> is provided to electrically connect the flow generator <NUM> to the humidifier <NUM>. Electrical power may be provided from the flow generator <NUM> to the humidifier <NUM>, although it should be appreciated that the humidifier may be provided with its own power source. Control signals may also be provided from the flow generator <NUM> to the humidifier <NUM> through the electrical connector <NUM>.

It should be appreciated that the humidifier <NUM> may include its own control system, for example, a microprocessor provided on a printed circuit board (PCB). The PCB may be located in the wall of the humidifier chamber <NUM> and may include a light, e.g. an LED, to illuminate the contents of the tub <NUM> to permit visual inspection of the water level. Referring to <FIG>, an aperture <NUM> may be provided in the wall of the humidifier chamber <NUM> to allow the light on the PCB to illuminate the humidifier chamber <NUM>. The aperture <NUM> is covered with a cover <NUM> to prevent access to the PCB and the light (e.g. LED) from the humidifier chamber <NUM>. The cover <NUM> may be transparent or colored to provide a colored light, such as a green light to appear within the humidifier chamber <NUM>. The light is provided to shine into the humidifier chamber <NUM> to allow the water level in the water tub <NUM> to be seen. Alternatively, multiple lights may be located on the PCB to provide different indications regarding the heating of the humidifier, for example an amber light may be provided to indicate that the humidifier is heating up to a required temperature and a blue light may be provided to identify when the humidifier is at the required temperature.

The humidifier <NUM> comprises the humidifier chamber <NUM> and the lid <NUM> which is pivotally connected to the humidifier chamber <NUM>. As shown in <FIG> and <FIG>, the lid <NUM> comprises a hinge portion <NUM> that is hinged to hinge portions <NUM> provided on the humidifier chamber <NUM>. Referring to <FIG>, a humidifier bottom <NUM> is provided to the humidifier chamber <NUM>, as shown in more detail in <FIG>. An opening member <NUM> is provided for releasing the lid <NUM> to allow the lid to be pivoted to the open position as described in more detail below.

Referring again to <FIG> and <FIG>, the lid <NUM> comprises catches <NUM> that are configured to be engaged by the latches <NUM> to maintain the lid in the closed position. The seal <NUM> also comprises wedge-shaped protrusions <NUM> that are configured to engage the water tub <NUM>, for example the tub lid <NUM>, when the lid <NUM> is in the closed position to push the tub <NUM> toward an outlet <NUM> of the humidifier chamber <NUM> to assist in forming a seal between the water tub outlet <NUM> and the humidifier chamber outlet <NUM>. A domed portion <NUM> is also provided on the seal <NUM> to push the water tub <NUM> against a heating plate <NUM> when the lid <NUM> is in the closed position. A circular seal section, or sealing ring, <NUM> is also provided to the seal <NUM> to seal, when the lid <NUM> is in the closed position, a tub emptying aperture <NUM> provided in the tub lid <NUM>.

Referring again to <FIG> and <FIG>, the humidifier chamber <NUM> also includes an air inlet <NUM> configured to receive the flow of breathable gas generated by the flow generator <NUM> when the humidifier <NUM> is connected to the flow generator <NUM> by the latches <NUM>. The inlet <NUM> directs the flow into the channel <NUM> (see <FIG>, <FIG> and <FIG>) in the tub lid <NUM> of the water tub <NUM>. The flow is directed by the channel <NUM> to the outlet <NUM> into the water tub <NUM>.

As shown in <FIG> and <FIG>, the humidifier chamber <NUM> comprises a humidifier cradle <NUM> that includes the air inlet <NUM>. The humidifier cradle <NUM> also includes the humidifier chamber outlet <NUM> to allow the humidified flow to be delivered to a delivery hose, tube, or conduit that is configured to be connected to the humidifier to deliver the humidified flow to a patient. The outlet <NUM> is provided in a back side of the humidifier cradle <NUM>. It should be appreciated that the outlet <NUM> may be provided on a side of the humidifier cradle <NUM>. Such a modification would also entail modifying the water tub <NUM> to align the outlet <NUM> of the tub <NUM> with the outlet <NUM> of the humidifier cradle <NUM>.

Referring to <FIG>, the heating plate <NUM> is provided to heat the water supply contained in the humidifier chamber <NUM>. A cradle bottom <NUM> is provided beneath the heating plate <NUM> and an insulation layer <NUM> is provided between the heating plate <NUM> and the cradle bottom <NUM>. The heating plate <NUM> may be formed, for example, of a nickel chrome alloy or anodized aluminum that allows the heating plate <NUM> to be formed thinner than currently available heating plates and with a larger surface area. The heating plate <NUM> may also include a thermistor that is controlled by a control circuit, for example, provided on the PCB.

Referring to <FIG>, the humidifier cradle <NUM> supports a lid closure member <NUM> that is movable between an open position and a closed position. The lid opening member <NUM> is provided at an end of the lid closure member <NUM> as shown in <FIG>. The lid closure member <NUM> comprises latches <NUM> that are configured to engage catches <NUM> of the lid <NUM> and retain the lid <NUM> in the closed position. The lid closure member <NUM> comprises a rod, or post, <NUM> that supports a spring <NUM> that biases the lid closure member <NUM> into the closed position. To open the lid <NUM>, the opening member <NUM> is pushed by the user against the bias of the spring <NUM>, to the right in <FIG>, to move the latches <NUM>, and the lid closure member <NUM>, to the open position. When the user releases the lid opening member <NUM>, the bias of the spring <NUM> returns the lid closure member <NUM> and the latches <NUM> to the closed position.

The lid closure member <NUM> is supported by a front retaining wall <NUM> of the cradle <NUM>. The lid closure member <NUM> includes tabs <NUM> that engage slots <NUM> formed in the front retaining wall <NUM>. The front retaining wall <NUM> also comprises slots <NUM> through which the latches <NUM> protrude. The slots <NUM>, <NUM> accommodate sliding movement of the lid closure member <NUM> and the latches <NUM> and the tabs <NUM>, respectively, engaged with the slots <NUM>, <NUM>.

As shown in <FIG>, the electrical connector <NUM> is connected to a plurality of wires <NUM>, for example, three wires, that are connected to a tube connector <NUM> that is shown in <FIG> and described in more detail hereinafter. The tube connector <NUM> comprises a plurality of contacts <NUM> that correspond in number to a number of wires <NUM> and are each connected to a respective wire. Although three wires <NUM> and three contacts <NUM> are shown in the drawings, it should be appreciated that a different number of wires and contacts may be provided, for example, two wires and two contacts. The tube connector <NUM> allows for the connection of a heated tube, for example, such as disclosed in <CIT>.

As shown in <FIG> and <FIG>, the humidifier cradle <NUM> is supported by a chamber bottom <NUM> of the humidifier chamber <NUM>. The chamber bottom <NUM> comprises a pair of latches <NUM> that are configured to engage corresponding catches (not shown) on the back of the humidifier cradle <NUM> to secure the humidifier cradle <NUM> to the chamber bottom <NUM>. The chamber bottom <NUM> also includes a bottom opening <NUM> through which the bottom of the humidifier cradle <NUM> extends. The chamber bottom <NUM> is configured to cover the wires <NUM> and the lid closure member <NUM> when connected to the cradle <NUM>, as shown in <FIG>.

Referring to <FIG>, an inner plate <NUM> may be secured to the humidifier cradle <NUM> over the latches <NUM> and the electrical connection <NUM>. As shown in <FIG> the inner plate <NUM> includes a plurality of apertures <NUM> that are configured to allow the latches <NUM> to extend therethrough and an aperture <NUM> configured to allow the electrical connector <NUM> to extend therethrough. The inner plate <NUM> also comprises a pair of apertures <NUM> that are configured to receive fasteners, for example, threaded fasteners <NUM> (<FIG>), to secure the inner plate <NUM> to the humidifier cradle <NUM>. A boss <NUM> may also be provided on the inner plate <NUM> to receive a fastener, for example, a threaded fastener <NUM> for securing the inner plate <NUM> to the humidifier cradle <NUM>. The inner plate <NUM> provides spillback protection to prevent water spilling back from the humidifier <NUM> to the flow generator <NUM>.

As shown in <FIG>, the latches <NUM> are provided on a latch plate <NUM> that is provided between the humidifier cradle <NUM> and the inner plate <NUM>. An end of the latch plate <NUM> is secured to a plate <NUM> that is also provided between the humidifier cradle <NUM> and the inner plate <NUM>. The plate <NUM> comprises posts <NUM> that support springs <NUM> that are configured to bias the latch plate <NUM> so that the latches <NUM> extend through the apertures <NUM> of the inner plate <NUM> in the positions shown in <FIG>. When the humidifier <NUM> is connected to the flow generator <NUM> the latches <NUM> engage catches (not shown) provided on the flow generator <NUM> and the latches <NUM>, and subsequently the latch plate <NUM>, are pushed against the bias of the springs <NUM> (to the right in <FIG>). Once the latches <NUM> fully engage the catches, the springs <NUM> bias the latch plate <NUM> and the catches <NUM> back to their starting position shown in <FIG> with the latches <NUM> engaged with the catches of the flow generator <NUM>. When the humidifier <NUM> is connected to the flow generator <NUM>, the electrical connector <NUM> connects with a corresponding electrical connector (not shown) in the flow generator <NUM> to permit the flow generator <NUM> to provide power and/or control signals to the humidifier <NUM>. As shown in the figures, the electrical connector <NUM> may comprise a terminal, or terminals, although it should be appreciated that the electrical connector <NUM> may comprise a contact, or contacts, that are received in terminals in the flow generator <NUM>.

Referring to <FIG>, the humidifier cradle <NUM> may comprise an outlet tube <NUM> provided through the outlet <NUM>. As shown in <FIG>, the outlet tube <NUM> may comprise a flange <NUM> that is configured to engage the back wall <NUM> of the humidifier cradle <NUM> and a groove <NUM> that is configured to receive a sealing ring <NUM> shown in <FIG>. The outlet tube <NUM> may be removed to allow replacement of all wet area parts of the humidifier, for example, the tub <NUM> and the outlet tube <NUM>. The outlet tube <NUM> may also be made out of a material that can be sterilized. It should be appreciated that the outlet tube <NUM> may also be disposable.

Referring to <FIG>, in the closed position the lid <NUM> provided with the seal <NUM> allows the humidifier chamber <NUM> to be sealed and become pressurized by the flow generator <NUM> when the flow generator generates a flow of air through the inlet <NUM> of the humidifier <NUM>. Pressurizing the humidifier chamber <NUM> reduces the pressure on the joints on the tub <NUM> to reduce leaks. Pressurizing the humidifier chamber <NUM> also reduces tolerances for insertion of the tub <NUM> with respect to seals on the inlet <NUM> and the outlet tube <NUM> of the humidifier chamber <NUM>. The humidifier chamber <NUM> also insulates the tub <NUM> to provide enhanced thermal properties and reduce power consumption. Insulating the tub <NUM> also reduces heat loss to the surroundings. The humidity output of the humidifier is determined directly from the water temperature. As the heat loss from the tub to the surroundings is reduced due to insulating the tub, less power is needed to reach the water temperature corresponding to a desired humidity output. In addition, incoming air is preheated as it passes the outside walls of the tub, before it enters the tub, which also reduces the power required to reach the water temperature corresponding to the desired humidity output.

As also shown in <FIG>, the inner plate <NUM> is secured to the humidifier cradle <NUM> by the threaded fasteners <NUM>, although it should be appreciated that other fastening members or methods may be used to secure the inner plate <NUM> to the humidifier cradle <NUM>. It should be appreciated that other latching structures and systems may be used to releasably secure the lid. For example, push to close and button to open operation systems may be used. Other examples include, but are not limited to, a rod latching system, a rotating latch or a hooking latch.

The outlet tube <NUM> and the tube connector <NUM> provide the ability to connect both a standard tube and a heated tube. As shown in <FIG>, the tube connector <NUM> and the contacts <NUM> are provided separately from the outlet tube <NUM>. A heated tube having corresponding electrical connections, e.g. terminals, may be provided in a rotational snap fit with the tube connection <NUM>. This type of connection provides ease of connection and reduces the tolerance stack of the respiratory apparatus <NUM>. A heated tube <NUM> suitable for connection to and use with the humidifier <NUM> is described in more detail with reference to <FIG>. As shown in <FIG>, a cover <NUM> may be connected to the back wall of the humidifier to cover the tube connector <NUM>, and the contacts <NUM>, when a non-heated tube is connected to the outlet tube <NUM>. The cover <NUM> may be formed of a pliable rubber or other suitable flexible material. Alternatively the cover <NUM> may be a separate component not attached to the humidifier that may be inserted over the connector <NUM>.

Referring to <FIG>, the seal <NUM> comprises a groove <NUM> configured to receive a corresponding edge, or rim, <NUM> of the lid <NUM> to connect the seal <NUM> to the lid <NUM>. The wedge-shaped protrusions <NUM> (see also <FIG>) are configured to engage the tub lid <NUM> when the lid <NUM> is in the closed position to bias the water tub <NUM> toward the back wall of the humidifier chamber <NUM> so that the outlet <NUM> is in sealing engagement with the outlet tube <NUM>. The seal <NUM> also comprises a sealing rim <NUM> that extends around the perimeter of the seal <NUM> and is configured to seal the perimeter of the lid <NUM> when the lid is in the closed position. An inner sealing rim <NUM> is provided around the aperture <NUM> of the seal <NUM> to seal around the window <NUM> of the lid <NUM>.

Referring to <FIG>, the water tub <NUM> comprises a tub base <NUM> and a flow plate <NUM>. The flow plate <NUM> comprises a dividing plate <NUM> that comprises an inlet <NUM> that is configured to receive the flow of breathable gas directed by the channel <NUM> of the tub lid <NUM>. The outlet <NUM> of the channel <NUM> is configured to direct the flow into the inlet <NUM> of the dividing plate <NUM> when the tub lid <NUM> is secured to the tub base <NUM> as described in more detail below.

The flow plate <NUM> also comprises a frame seal <NUM> that is configured to seal the perimeter of the tub base <NUM> when the tub lid <NUM> is connected to the tub base <NUM>. The frame seal <NUM> is connected to the dividing plate <NUM> by a plurality of supports, or bridges, <NUM>. A gap <NUM> is provided between the dividing plate <NUM> and the frame seal <NUM> by the bridges <NUM>.

A water level indicator <NUM> is provided on the dividing plate <NUM> of the flow plate <NUM> to provide an indication of the water level. As shown in <FIG>, the water level indicator <NUM> may include a frusto-conical portion. As shown in <FIG>, the water level indicator <NUM> may be cone shaped. A small drain hole <NUM> is located in the bottom of the water level indicator <NUM> to allow the water to fill up the water level indicator <NUM> and then drain out of the bottom of the water level indicator <NUM> to the tub base <NUM> as the water level decreases in the tub base <NUM>. The water level indicator <NUM> provides an indication of the water level in the tub <NUM> by the water level indicator <NUM> being filled with water once the water level in the tub base <NUM> reaches the level of the small drain hole <NUM>, which then allows the water level in the tub base <NUM> to be filled until the water in the water level indicator <NUM> reaches the desired level such as that indicated by indicia <NUM>. Although the water level indicator <NUM> provides an indication of the water level, as the flow of breathable gas is directed to the surface of the water contained in the tub base <NUM>, the water level is not critical as the flow is in good contact with the surface of the water. The water level indicator <NUM> may be provided with indicia <NUM> to indicate a maximum water level of the water tub <NUM>. The light emitted from the PCB through the aperture <NUM> allows the water level in the water level indicator <NUM> to be seen.

Referring to <FIG>, according to a sample embodiment of the technology, the water tub <NUM> is configured to be disposable. The tub <NUM> comprises the tub base <NUM> configured to contain a supply of water. The tub lid <NUM> is provided on the tub base <NUM>. The tub lid <NUM> may be secured to the tub base <NUM> by, for example, welding. The tub <NUM> may be formed, for example, of plastic material, metal or a combination of metal and plastic.

As shown in <FIG> and <FIG>, the flow plate <NUM> is provided on the tub base <NUM>. The tub lid <NUM> comprises the channel <NUM> that receives the flow of breathable gas generated by the flow generator <NUM> that enters the humidifier <NUM> through the air inlet <NUM>. As shown in <FIG>, the channel <NUM> comprises the channel outlet <NUM> that is received in the inlet <NUM> in the dividing plate <NUM>. The dividing plate <NUM> ensures that the flow of breathable gas flows across the whole tub as air enters into the center and flows to the outside of the tub and then up through the gap <NUM> between the walls of the tub base <NUM> and the dividing plate <NUM> to the outlet <NUM> of the tub lid <NUM>.

Referring to <FIG>, the tub base <NUM> comprises a tub base rim <NUM> that is engaged by a latch <NUM> of the tub lid <NUM> to connect the tub base <NUM> and the tub lid <NUM>. The frame seal <NUM> comprises a seal <NUM> that is provided between the latch <NUM> of the tub lid <NUM> and the rim <NUM> at the tub base <NUM>. A wedge <NUM> is provided on each bridge <NUM> and connected to the seal <NUM> to force the seal <NUM> into a sealing engagement between the rim <NUM> and a latch <NUM>. The wedge <NUM> is engaged by a wedge <NUM> of the tub lid <NUM> to force the seal <NUM> into sealing engagement between the rim <NUM> and the latch <NUM>.

Referring to <FIG>, a humidifier tub that is configured to be disposable according to another sample embodiment is illustrated. The humidifier tub <NUM> may comprise a tub base <NUM>, a tub lid <NUM> having a channel <NUM>. The tub lid <NUM> may also comprise a tub outlet <NUM> for delivering a humidified flow of breathable gas. A tub emptying aperture <NUM> may also be provided in the tub lid <NUM>.

Referring to <FIG>, the humidifier tub <NUM> may also comprise a flow plate <NUM> having a dividing plate <NUM>. An inlet <NUM> is provided on the dividing plate <NUM> that corresponds to the outlet <NUM> (<FIG>) of the channel <NUM> of the tub lid <NUM>. The dividing plate <NUM> of the flow plate <NUM> is connected to a frame seal <NUM> by a plurality of bridges <NUM>. A gap <NUM> is provided between the frame seal <NUM> and the dividing plate <NUM>.

Referring to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, the humidifier tub <NUM> may also include a water level indicator <NUM>. The water level indicator <NUM> may be provided on the dividing plate <NUM> of the flow plate <NUM>. As shown, for example, in <FIG>, the water level indicator <NUM> may have a generally polygonal perimeter, including a generally rectangular portion <NUM> and a generally triangular portion <NUM>. It should be appreciated, however, that other perimeter shapes may be provided for the water level indicator <NUM>, including regular polygonal shapes (e.g. square, rectangular, pentagonal), or polygonal shapes that are combinations of regular polygonal shapes, or polygonal shapes combined with curvilinear surfaces.

As shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, the water level indicator <NUM> comprises a drain hole <NUM> to allow the water to drain out of the bottom of the water level indicator <NUM> to the tub base <NUM>. As shown, for example, in <FIG>, the drain hole <NUM> is not provided at the bottom of the water level indicator <NUM>, but is located at an intermediate position between the bottom and the top of the water level indicator <NUM> to allow any pooled water to drain away from the intermediate position. In this embodiment the water level indicator <NUM> is not filled with water but the water level is indicated against the sloping surface of the water level indicator as described in more detail below. As shown in <FIG>, the drain hole <NUM> is located at a position generally corresponding to the plane of the dividing plate <NUM> of the flow plate <NUM>. As also shown in <FIG>, and <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, the water level indicator <NUM> may include indicia <NUM> that indicates a maximum fill level of the humidifier tub <NUM>. As shown in the figures, the indicia <NUM> may be provided at the same level of the water level indicator <NUM> as the drain hole <NUM>.

Referring to <FIG>, the generally triangular portion of the water level indicator <NUM> extends below the frame seal <NUM> into the tub base <NUM> when the tub is in the assembled condition and includes a first angled wall <NUM> and a second angled wall <NUM>. As the water level of the tub base <NUM> increases during fill up, the water level will initially contact the bottom of the water level indicator <NUM>. As the water level continues to increase, the second angled wall <NUM> directs the water level toward the drain hole <NUM> and the indicia <NUM> which are provided in the angled wall <NUM> between the frame seal <NUM> and the dividing plate <NUM> of the flow plate. As the water level continues to increase and approaches the drain hole <NUM>, the visibility of the water level relative to the indicia <NUM> increases. As the indicia <NUM> is provided at the same level as the drain hole <NUM>, the maximum fill level of the tub <NUM> is detected when the water level reaches the level of the drain hole <NUM> and the indicia <NUM>.

Referring to <FIG>, <FIG>, <FIG> and <FIG>, the seal <NUM> may be provided on the periphery of the wedge <NUM> of the bridge <NUM>. The wedge <NUM> of the tub lid <NUM> is configured to engage the wedge <NUM> of the dividing plate <NUM> of the flow plate <NUM> to force the seal <NUM> between the rim <NUM> of the tub base <NUM> and the latch <NUM> of the tub lid <NUM>. As shown in <FIG>, the wedge <NUM> may comprise a flange <NUM> around its perimeter that includes a slot <NUM> that is configured to receive a portion of the seal <NUM>, as shown, for example, in <FIG>.

Referring to <FIG>, a humidifier water tub <NUM> is configured to be disposable according to still another sample embodiment as illustrated. The humidifier tub <NUM> comprises a tub base <NUM> and a tub lid <NUM>. The tub lid <NUM> includes an oval opening <NUM> and a sump region <NUM> that surrounds the outlet <NUM> of the channel <NUM> that is formed in the tub lid <NUM> to direct the flow of air from the flow generator to the water contained in the tub <NUM>. The sump region <NUM> facilitates filling the tub <NUM> by providing a larger area for entry of water than the outlet <NUM> of the flow channel <NUM>.

The tub lid <NUM> also comprises a cover portion <NUM> that covers the section of the flow channel <NUM> from the flow generator <NUM> to the inlet <NUM> of the tub <NUM> that is angled down towards the flow generator <NUM>. The cover portion <NUM> prevents any water from flowing back into the flow generator <NUM> if the tub <NUM> was filled with water while still connected to the flow generator <NUM> as water may only be poured into the tub in the region provided by the opening <NUM> which is designed to channel the water down towards the outlet <NUM>.

As shown in <FIG>, a water level indicator <NUM> may be provided to the humidifier tub <NUM> that is visible through the window <NUM> of the lid <NUM>. The water level indicator <NUM> may comprise a base portion <NUM> and an angled portion <NUM> extending from the base portion <NUM>. The angled portion <NUM> may include markings <NUM> to indicate various water levels. The angled portion <NUM> may also include indicia <NUM> to indicate a maximum water fill level.

The water level indicator <NUM> may be removably connected to the dividing plate <NUM> of the flow plate <NUM> by posts <NUM>. The posts <NUM> may be inserted into apertures <NUM> in the dividing plate <NUM> of the flow plate <NUM>. As shown in <FIG>, the posts <NUM> may include latches <NUM> that are resiliently moveable with respect to the remaining portions of the posts <NUM>. The latches <NUM> may be provided at the ends of leg portions <NUM> which are attached to the base <NUM> of the water level indicator <NUM>. The leg portions <NUM> may be connected by a cross member <NUM>, as shown in <FIG> and <FIG>.

The water level indicator <NUM>, for example, the angled portion <NUM>, may be formed of a colored plastic material, for example yellow. The water level indicator <NUM> may be, for example, translucent. When the tub <NUM> is filled with water, the water level indicator <NUM> may appear to change color, for example appearing slightly darker or a greenish-yellowish color as the water level rises.

As shown in the figures, the water level indicator <NUM> may be a rounded D-shape, although it should be appreciated that other shapes may be used. It should also be appreciated that the water level indicator <NUM> may be attached to the dividing plate <NUM> of the flow plate <NUM> by structures other than the post <NUM> as shown and described in the drawings. For example, the water level indicator <NUM> may be adhered to the dividing plate <NUM>, or the water level indicator <NUM> may be integrally formed, for example molded, with the dividing plate <NUM> of the flow plate <NUM>.

Referring to <FIG>, a tub <NUM> according to another embodiment of the technology is configured to be reusable, and cleanable. The tub base <NUM> comprises a plurality of clips <NUM> that are configured to engage and retain the tub lid <NUM> in connection with the tub base <NUM>. A clip <NUM> is also provided and comprises an aperture <NUM> to accommodate the outlet <NUM> of the flow plate, as shown in <FIG>.

The flow plate <NUM> is configured to be removable from the tub base <NUM> and it is not permanently secured to the tub base <NUM>. As shown in <FIG> and <FIG>, the bridges <NUM> of the flow plate <NUM> include a wedge <NUM> that is connected to a seal <NUM>. The seal <NUM> is forced into sealing engagement between a rim <NUM> of the tub lid <NUM> and the rim <NUM> of the tub base <NUM>. The clip <NUM> is provided to clip the tub lid <NUM> to the tub base <NUM> with the seal <NUM> secured in between in sealing engagement. A first portion <NUM> of the clip <NUM> engages the tub base <NUM> up to the rim <NUM> and a second portion <NUM> of the clip <NUM> is configured to engage a projection <NUM> of the tub lid <NUM> to secure the tub lid <NUM> and the tub base <NUM> in engagement.

The humidifier <NUM> does not include any seals that are provided under the water supply of the tub base <NUM>. The lid <NUM> comprises the seal <NUM> to allow for pressurizing of the humidifier chamber <NUM> with the flow provided by the flow generator <NUM> to reduce the pressure on the tub joints, including the disposable tub and the reusable, cleanable tub, thus reducing leaks. Pressurizing the humidifier chamber also reduces tolerances for insertion of the water tub with respect to seals on the inlet of the humidifier and the outlet tube <NUM> of the humidifier <NUM>. The sealing ring <NUM> provided to the outlet tube <NUM> is provided on an outer surface of the humidifier cradle <NUM> and not provided under the water of the supply contained in the tub base <NUM>.

Referring to <FIG>, a water tub <NUM> according to another sample embodiment is configured to be reusable and cleanable. The tub <NUM> may have a water level indicator <NUM> similar to the water level indicator described with respect to the previous embodiments. It should be appreciated that the tub <NUM> may be provided with any of the water level indicators described herein.

The tub lid <NUM> may include the cover portion <NUM> to cover the inlet region of the flow channel <NUM> adjacent to the inlet <NUM> of the humidifier <NUM> that is connected to the flow generator <NUM>.

As shown in <FIG>, the tub lid <NUM> may be secured to the tub base <NUM> by a plurality of clips <NUM>, <NUM>. The clip <NUM> may have an aperture configured to accommodate the outlet <NUM> of the tub <NUM>. The tub lid <NUM> may include projections <NUM> that are received in apertures <NUM> in the clips <NUM>. The tub lid <NUM> may also include projections <NUM> that are received in apertures <NUM> provided in the clip <NUM>.

As also shown in <FIG>, the tub lid <NUM> may include recesses <NUM> to accommodate the fingers of a user of the tub <NUM> to provide a space between the tub lid <NUM> and the clips <NUM> as the user inserts the tub lid <NUM> on to the tub base <NUM> so that the projections <NUM> are received in the apertures <NUM>. The recesses <NUM> may also accommodate the fingers during removal of the lid <NUM> from the base <NUM>, for example to allow the parts of the tub <NUM> to be disassembled and cleaned.

It should be appreciated that the reusable and cleanable tubs may include a water level indicator as discussed above with respect to the embodiments of the disposable tub. It should also be appreciated that the reusable and cleanable tubs may include more than one water level indicator as discussed above with respect to the embodiments discussed above. It should further be appreciated that the water level indicator, or indicators, or the tub may not include indicia to include a maximum water level.

Referring to <FIG>, a heated tube <NUM> is connectable to the outlet tube <NUM> of the humidifier <NUM>. The heated tube <NUM> comprises a cuff <NUM> that includes a humidifier connector <NUM> that is configured to be connected to the tube connector <NUM> of the humidifier <NUM>. The humidifier connector <NUM> comprises terminals <NUM> that are configured to receive the contacts <NUM> of the tube connector <NUM> when the humidifier connector <NUM> and the tube connector <NUM> are connected. The cuff <NUM> may be formed as described, for example, in U. Application <NUM>/<NUM>,<NUM>. The heated tube may include, for example, two or three wires and may transmit and receive signals to and from a controller in the humidifier and/or the flow generator as described in U. Application <NUM>/<NUM>,<NUM>. The end of the humidifier connector <NUM> that is configured for insertion into the tube connector <NUM> of <FIG> may include an angle <NUM> to facilitate insertion of the connector <NUM> into the tube connector <NUM>. The angle <NUM> may be between about <NUM>°-<NUM>°.

Referring to <FIG>, the heated tube <NUM> may be connected to a patient interface, e.g. a mask, by a cuff <NUM> provided at the end of the heated tube <NUM>. An aerofoil fixture <NUM> is provided in the cuff <NUM> and includes a thermistor <NUM>, as shown in <FIG>. The shape of the aerofoil fixture <NUM> provides a smooth flow around the aerofoil fixture <NUM> so that the thermistor <NUM> provides a good reading of the temperature of the flow of breathable gas in the tube <NUM>. The cuff <NUM> may be formed by, for example, overmolding on a pre-block <NUM>, or any method disclosed, for example, in <CIT>. The thermistor <NUM> is connected to the wires in the heated tube <NUM> by lead frames <NUM>. The temperature sensed by the thermistor <NUM> may be provided as a signal from the thermistor <NUM> through the lead frames <NUM> and the wires to a controller located in the humidifier and/or the flow generator.

The tube <NUM> may have a <NUM> internal diameter. The tube <NUM> may be heated using wires as described in <CIT>. A non-heated <NUM> air delivery tube my also be used. The <NUM> internal diameter tube may be connected to the tube connector <NUM> and the patient interface using a <NUM> isotaper connection.

While the technology has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the technology is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements. Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. Further, each independent feature or component of any given assembly may constitute an additional embodiment. Furthermore, each individual component of any given assembly, one or more portions of an individual component of any given assembly, and various combinations of components from one or more embodiments may include one or more ornamental design features. In addition, while the invention has particular application to patients who suffer from OSA, it is to be appreciated that patients who suffer from other illnesses (e.g., congestive heart failure, diabetes, morbid obesity, stroke, barriatric surgery, etc.) can derive benefit from the above teachings. Moreover, the above teachings have applicability with patients and non-patients alike in non-medical applications.

In this specification, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of'. A corresponding meaning is to be attributed to the corresponding words "comprise," "comprised" and "comprises" where they appear.

Claim 1:
A respiratory apparatus (<NUM>) for delivering a flow of breathable gas to a patient, comprising a flow generator (<NUM>) and a humidifier (<NUM>),
the flow generator (<NUM>) being configured to generate a flow of breathable gas (<NUM>), and
the humidifier (<NUM>) comprising a humidifier chamber (<NUM>) and a tub (<NUM>), the tub (<NUM>) being configured to contain a supply of water and being insertable into the humidifier chamber (<NUM>),
the humidifier (<NUM>) further comprising a humidifier lid (<NUM>) attached to a wall of the humidifier chamber (<NUM>) and pivotable between an open position in which the tub (<NUM>) is insertable from the top into the humidifier chamber (<NUM>) and a closed position in which the humidifier lid (<NUM>) covers the inserted tub (<NUM>),
the humidifier chamber (<NUM>) further comprising an inlet (<NUM>) configured to receive the flow of breathable gas generated by the flow generator, a bottom (<NUM>) with a heating plate (<NUM>) configured to heat the supply of water contained in the tub (<NUM>), a back wall (<NUM>) with an opposing front retaining wall (<NUM>), and two opposing lateral sides, said inlet (<NUM>) being provided on one of the opposing lateral sides,
wherein the tub (<NUM>) comprises a tub base (<NUM>) and a tub lid (<NUM>),
wherein the flow generator (<NUM>) and the humidifier (<NUM>) are connectable with the lateral side of the humidifier chamber (<NUM>) comprising the inlet (<NUM>) relative to the flow generator (<NUM>) so that latches on the humidifier (<NUM>) are received in corresponding recesses or catches on the flow generator (<NUM>).