Patent Description:
In modern clinical medicine, a respiratory apparatus is commonly used for patients with respiratory illnesses such as acute respiratory distress syndrome, severe asthma and chronic obstructive pulmonary disease, as well as used for anesthesia and respiratory management during surgery, first aid resuscitation, and even domestic use for supportive treatment. A respiratory apparatus is a vital medical device that can prevent and treat respiratory failure, reduce complications and prolong the patient's life.

Current respiratory apparatuses have a number of drawbacks. For example, when air is drawn into a respiratory apparatus by a blower, noise is generated by the friction between the air flow and the gas inlet passage. The noise is particularly obvious when the respiratory apparatus is used in a quiet environment or when the patient is sleeping, potentially causing a physical and mental annoyance to the patient.

There are many designs of a noise reduction device to reduce the noise generated at the gas inlet of the respiratory apparatus. For example, <CIT>, discloses a noise reduction device including a gas passage defined by a side wall to direct gas flow into the respiratory apparatus. The gas may only travel an angular distance of <NUM> degrees before reaching the gas outlet, which is too short for the gas passage to reduce the turbulent gas flow and thus provide an effective noise reduction. Accordingly, it has been found that such a design cannot provide significant noise reduction.

It is therefore desirable to provide an improved noise reduction device for the gas to flow from the gas inlet to the gas outlet in order to reduce noise level at the gas inlet of a respiratory apparatus significantly.

<CIT> discloses a silencing device including a main body and an upper cover, and the upper cover is buckled on the main body through a flange provided at the edge of the cover to form a planar spiral air passage arranged in the silencing device. The spiral air passage includes an air inlet arranged at the outer end of the spiral air passage, and an air outlet disposed at the center of the inner end of the spiral air passage and perpendicular to the spiral plane of the spiral air passage.

<CIT> discloses a silencing device, which includes an upper cover, a middle body and a base. The middle body is located between the upper cover and the base. The upper cover is provided with a spiral stereoscopic rotary air inlet integral with the upper cover.

<CIT> provides a silencing cover, including a cover body, with a planar spiral air passage disposed therein and an air passage outlet disposed thereon, and the planar spiral air passage forms an air passage inlet along the circumferential direction of the cover body.

<CIT> provides an oxygen enricher of which the noise caused by cooling air for a motor and the like and adsorbed nitrogen exhaust is decreased effectively by that: a guide is installed in the exhaust silencing chamber to rotate the exhaust gas introduced from the exhaust inlet and to exhaust the gas from the exhaust outlet to the outside.

The present disclosure provides a noise reduction device for a respiratory apparatus to, at least, solve the technical problem of the noise generated by fat the gas inlet of the current respiratory apparatus.

According to an aspect of the present disclosure, there is provided a noise reduction device for a respiratory apparatus including a body configured to be mounted on the gas inlet of the respiratory apparatus, and a cover configured to be detachably engageable with the body for forming a gas inlet and a gas passage. The body includes a side wall and a gas outlet and the cover includes a guiding member defining at least a part of the gas passage. The guiding member is configured to be coupled with the side wall of the body to form the gas passage between the body and the cover. The gas passage formed directs a flow of gas to an angular rotation about a centre of the gas outlet of at least <NUM> degrees to <NUM> degrees relative to the gas inlet before discharging at the gas outlet. The noise reduction device further includes: a locking mechanism for slidably locking the cover to the body. The locking mechanism includes at least two slots arranged on the body, and at least two corresponding tabs arranged on the cover. The cover is engaged with the body for forming the gas inlet and the gas passage by that the at least two corresponding tabs arranged on the cover are slidably locked to the at least two slots arranged on the body respectively.

According to another aspect of the disclosure, there is provided a respiratory apparatus including the noise reduction device substantially as described herein. The respiratory apparatus may further include a pressurized gas inlet for supplying a pressurized gas; a chamber in fluid communication with the gas outlet of the noise reduction device and the pressurized gas inlet for mixing atmospheric air and the pressurized gas; and a noise-damping device disposed downstream of the chamber.

Without intending to be limited by theory, it is believed that the noise reduction device in the present disclosure provides significant advantages over, for example, current noise reduction devices that only allow a gas flow to turn about <NUM> degrees relative to the gas inlet before discharging at the gas outlet. Specifically, it is believed that the noise reduction device in the present disclosure may provide a longer path, and in an embodiment herein, a longer spiral passage for the gas to flow from the gas inlet to the gas outlet so as to decrease the turbulence and resistance of gas flow to a larger extent and hence reducing the noise caused by the friction between the turbulent gas flow and the gas inlet of the respiratory apparatus. Moreover, it is believed that the configuration of the guiding member being located on the cover provides an easier and more convenient way to clean the gas passage. The cover can be disengaged from the body and subject to common sterilization methods of medical equipment. Such arrangement may also facilitate replacement of the cover in case abrasion or damage is found on the guiding member which may increase turbulent flow of the incoming gas and thus causes noise.

The figures herein are for illustrative purposes only and are not necessarily drawn to scale.

The present disclosure relates to a noise reduction device which is useful to minimize the noise generated when a gas, in particular atmospheric air or pressurized gas, enters the associated apparatus such as, but is not limited to, a respiratory apparatus which requires a supply of a gas. The respiratory apparatus may be, but is not limited to, a humidifier, a respirator, a nebulizer, etc..

The gas useful herein typically includes atmospheric air or air enriched with oxygen gas, as desired. The gas herein may be at ambient room temperature, higher than room temperature, or lower that room temperature, as desired. The gas herein may be at the ambient pressure of the surrounding environment, or at a higher pressure than the surrounding environment. The gas herein may be at ambient humidity, more humid than ambient humidity, or drier than ambient humidity, as desired.

<FIG> shows a noise reduction device disclosed in, for example, <CIT> (see above). The noise reduction device includes a gas passage <NUM> defined by a side wall <NUM>. A gas inlet <NUM> is provided at outer end of the gas passage <NUM> and a gas outlet <NUM> with a centre <NUM> is provided at the inner end of the gas passage <NUM>. Two dashed lines are added to <FIG>, with one extending from the centre <NUM> to the gas inlet <NUM> and one extending from the centre <NUM> to an inner end <NUM> of the side wall <NUM>, to define an angular rotation αabout the centre <NUM> to show the shortest distance for the incoming gas to travel from the gas inlet <NUM> to the gas outlet <NUM>, which is about <NUM> degrees. In other words, gas may only travel about <NUM> degrees before reaching the gas outlet, which is too short for the gas passage to reduce the turbulent gas flow and thus provide an effective noise reduction. Accordingly, it has been found that such a design cannot provide significant noise reduction.

Referring to <FIG>, there is illustrated an embodiment of a noise reduction device of the present disclosure. The noise reduction device <NUM> of the present disclosure has a cover <NUM> and a body <NUM>. The cover <NUM> and the body <NUM> are, preferably, separately manufactured and can be detachably engaged with each other through a locking means such as sliding and screwing.

In this embodiment, the cover <NUM> and the body <NUM> may be made of a plastic, such as a thermoset plastic, a resin, a polymeric material, etc. Such plastics are known in the art and typically include materials such as polycarbonate, polyethylene, polypropylene, polyvinyl chloride, acrylonitrile butadiene styrene, polymethyl methacrylate, phenolics, melamine formaldehyde, polysulfone, polyetherimide, polyethylene terephthalate, urea-formaldehyde, polyether ether ketone, and a combination thereof. Furthermore, the plastic may incorporate an anti-microbial compound by, for example, containing a coating, integrating the anti-microbial compound into the plastic, etc..

<FIG> shows an embodiment of the body <NUM> before engaging with the cover (see <FIG> at <NUM>). The body <NUM> has a gas outlet <NUM> and is preferably arranged to be mounted to a respiratory apparatus (see <FIG> at <NUM>) so as to discharge a gas into the respiratory apparatus for subsequent use. In this embodiment, the body <NUM> is configured with a cavity <NUM> surrounded by a side wall <NUM>. The side wall <NUM> extends perpendicularly from periphery of an inner surface <NUM> and includes a first end portion <NUM>. The cavity <NUM> may be open or closed depending on the configuration of the side wall <NUM>. In this embodiment, the cavity <NUM> is open with the side wall <NUM> configured as a C-shape, i.e. leaving an open portion <NUM>. At least part of the side wall <NUM> can be coupled to the cover (see <FIG> at <NUM>) for forming a tight seal.

The cavity <NUM> may house a filter <NUM> (shown as a dotted line) therein. The filter <NUM> may be provided to filter dust, pollen, mold, bacteria, etc. from the gas, particularly atmospheric air, before the gas enters the respiratory apparatus. In an embodiment where the filter <NUM> is detachably arranged in the cavity <NUM> of the body <NUM>, the filter <NUM> can be replaced with a new one either randomly or regularly so as to keep the filtered gas free from, or at least with a reduced amount of, dust, pollen, mold, bacteria, etc. This is particularly advantageous when the respiratory apparatus is used for clinical applications. It is also believed that the filter <NUM> can also act as a noise suppressor to reduce the noise generated in the cavity <NUM> when the gas passes through the noise reduction device (see <FIG> at <NUM>). The filter <NUM> may be, for example, a paper filter, foam filter, cotton filter, or high-efficiency particulate air filter. One skilled in the art would appreciate that various suitable filters can be applied to the noise reduction device <NUM> of the present disclosure.

In this embodiment, the gas outlet <NUM> is radially offset and is supported by a supporting structure <NUM> which has a plurality of upright protrusions <NUM> on the inner surface <NUM> connecting to the gas outlet <NUM>. The gas outlet <NUM> may be aligned with the gas pathway in the respiratory apparatus, thereby reducing the formation of turbulence. One skilled in the art would appreciate that the gas outlet <NUM> may be positioned at the centre of the cavity <NUM> to achieve the similar purpose.

The cavity <NUM> may further include a converging portion <NUM> on the inner surface <NUM> which converges towards the gas outlet <NUM> so as to facilitate the gas flow. In addition to guiding the flow of the gas towards the gas outlet <NUM>, the supporting structure <NUM> may also help to hold the filter <NUM> in place. Without intending to be limited by theory, it is also believed that the upright protrusions <NUM> and supporting structure <NUM> may further enhance the structural integrity of the body <NUM> and/or the cover (see <FIG> at <NUM>). The upright protrusions <NUM> and the converging portion <NUM> support the filter <NUM> which may help to separate the filter <NUM> from the inner surface <NUM> to increase the effective surface area of the filter <NUM> and hence increase the amount of filtered gas flow. This may synergistically help to protect a blower of the respiratory apparatus (see <FIG> at <NUM>) by reducing its workload and thus further reducing the noise produced. In this embodiment, the upright protrusions <NUM> of the supporting structure <NUM> are configured as extending, continuously or discontinuously, radially from the gas outlet <NUM>.

In the embodiment of <FIG>, the body <NUM> is configured to detachably engage with the cover <NUM>. Preferably, the body <NUM> is enclosed by the cover <NUM> after engaging with the cover <NUM>. The body <NUM> may include two slots <NUM> (or tabs) respectively arranged on substantially diametrically opposite sides of the side wall <NUM> for complementary slide locking with corresponding tabs (or slots) on the cover <NUM>.

Turning to the cover <NUM>, with reference to <FIG> showing a rear view of it, the cover <NUM> has a side wall <NUM> and an inner surface <NUM> facing towards the inner surface (see <FIG> at <NUM>) of the body (see <FIG> at <NUM>) when it is engaged with the body (see <FIG> at <NUM>) to form the noise reduction device (see <FIG> at <NUM>). The side wall <NUM> extends perpendicularly from the periphery of the inner surface <NUM> and partially surrounds the cover <NUM> to form a cavity <NUM>. In this embodiment, the cavity <NUM> is open with the side wall <NUM> configured substantially as a C-shape to define a second end portion <NUM> and a third end portion <NUM> on the side wall <NUM> respectively, leaving an open portion <NUM>.

The cover <NUM> has a guiding member <NUM> being configured to extend substantially perpendicularly from the inner surface <NUM>. The guiding member <NUM> itself defines at least a part of a gas passage <NUM>, and is configured in a way to form the gas passage <NUM> between the body (see <FIG> at <NUM>) and the cover <NUM> when they are engaged together. One skilled in the art would appreciate that possible configurations of the guiding member such as a spiral including Cotes's spiral, Archimedean spiral and golden spiral, may be used depending on the desired design and noise reduction requirements. Preferably, the area enclosed by the guiding member <NUM> is at least twice than area of the gas outlet <NUM> in order to increase the effective filtering area of the filter <NUM> and reduce gas resistance, thereby further reducing noise production.

In this embodiment, the guiding member <NUM> is substantially in form of a C-shape. The guiding member <NUM> has a fourth end portion <NUM> and a fifth end portion <NUM> defining an opening <NUM> aligning with the open portion <NUM> and to be closed by the side wall <NUM> of the body (see <FIG> at <NUM>) when the body (see <FIG> at <NUM>) and the cover <NUM> are engaged. The fourth end portion <NUM> includes a projection <NUM> for additional engagement and position fixing with the first end portion <NUM> of the body <NUM> (see <FIG> at <NUM>) when the body <NUM> and the cover <NUM> are engaged together.

The fourth end portion <NUM> and the second end portion <NUM> together define a flow deflecting portion <NUM> being a part of the gas passage <NUM> to provide an enlarged section for an increased level of gas entry, and facilitate a spiral flow of the gas into the gas passage. The flow deflecting portion <NUM> may also avoid transmission of noise from the blower inside the respiratory apparatus to the outside environment.

In this embodiment, the cover <NUM> is detachably engageable with the body (see <FIG> at <NUM>) and preferably encloses the body <NUM> after engagement. Similar to the body <NUM>, two tabs <NUM> may be respectively arranged on substantially diametrically opposite sides of the side wall <NUM> for complementary slide locking with corresponding slots <NUM> on the body <NUM> to form a bayonet mount.

<FIG> shows the noise reduction device <NUM> when the body <NUM> and the cover <NUM> are slidably locked to one another. In this embodiment, the body <NUM> is oriented and inserted into the cavity (see <FIG> at <NUM>) of the cover <NUM> with the tabs (see <FIG> at <NUM>) being received in the slots (see <FIG> at <NUM>). A slight turning of either the body <NUM> or the cover <NUM> locks the two components with a bayonet lock as a locking mechanism <NUM> to hold them in place. In the present disclosure, the locking mechanism <NUM> includes at least one slot (see <FIG> at <NUM>) arranged on the body <NUM>, and at least one corresponding tab (see <FIG> at <NUM>) arranged on the cover <NUM>. In another embodiment, the locking mechanism <NUM> may include a pair of magnetic members arranged on the cover <NUM> and the body <NUM> as the locking means. One skilled in the art would appreciate that other locking means, such as a push lock, a slide lock, a screw, a plug and/or a combination thereof, may be used herein.

In this figure, the outer surface <NUM> of the body <NUM> shows the gas outlet <NUM> which is to be mounted to a respiratory apparatus (see <FIG> at <NUM>) for discharge of a gas into the respiratory apparatus. The flow deflecting portion <NUM>, which is not covered by the body <NUM>, is shown adjacent to the second end portion <NUM> of the side wall <NUM>. Adjacent to the flow deflecting portion <NUM> is a gas inlet <NUM> arranged between the side wall (see <FIG> at <NUM>) and the side wall <NUM>. The first end portion <NUM> of the side wall <NUM> is arranged adjacent to the gas inlet <NUM>. Two tabs <NUM> (only one is shown) are disposed on substantially diametrically opposite ends of the outer surface <NUM> for detachable mounting on the respiratory apparatus (see <FIG> at <NUM>) through sliding. One skilled in the art would appreciate that other locking means such as screwing may also be used depending on the configuration of the respiratory apparatus.

Referring to <FIG>, when the body (see <FIG> at <NUM>) and the cover <NUM> are engaged, the side wall <NUM> of the body (see <FIG> at <NUM>) is received in the gas passage <NUM> and the body (see <FIG> at <NUM>) is enclosed by the cover <NUM>. The location of the first end portion (see <FIG> at <NUM>) is shown as a dotted line forming a seal with the projection <NUM> and abutting the fourth end portion <NUM> of the guiding member <NUM> to define the planar spiral gas passage <NUM> between the side wall <NUM> and the guiding member <NUM>, wherein the fifth end portion <NUM> spaces apart from the side wall (see <FIG> at <NUM>) to form a gap <NUM> and the gas inlet <NUM> is arranged to be perpendicularly to the gas outlet <NUM> in this embodiment. In an embodiment where a filter (see <FIG> at <NUM>) is placed in the body (see <FIG> at <NUM>), the guiding member <NUM> is in contact with the filter (see <FIG> at <NUM>) when the body (see <FIG> at <NUM>) and the cover <NUM> are engaged so as to keep the filter (see <FIG> at <NUM>) in place by sandwiching the filter (see <FIG> at <NUM>) between the guiding member <NUM> and the body (see <FIG> at <NUM>). This also helps to avoid oscillation of the filter (see <FIG> at <NUM>) between the body (see <FIG> at <NUM>) and the cover <NUM> when the gas passes the filter (see <FIG> at <NUM>).

During operation, a gas, typically atmospheric air, is drawn to the gas inlet <NUM> preferably by a blower of the respiratory apparatus, where the gas travels from the flow deflecting portion <NUM> of a wider cross section to the gas passage <NUM> of a narrower cross section for a smoother gas flow by maintaining or even reducing gas resistance. The gas then flows through the gas passage <NUM>, the gap <NUM>, and to the opening <NUM>. The gas then passes through the filter (see <FIG> at <NUM>) which is in contact with the guiding member <NUM> when the body (see <FIG> at <NUM>) and the cover <NUM> are engaged, and finally reaches the gas outlet (see <FIG> at <NUM>) (shown by arrows). One skilled in the art would appreciate that with such configuration, the incoming gas is forced to travel an angular rotation β about a centre <NUM> of the gas outlet (see <FIG> at <NUM>) of at least <NUM> degrees from the gas inlet <NUM> to the gas outlet <NUM>, which is over <NUM> times longer than the gas passage <NUM> described in <FIG> without substantive increment in size of the noise reduction device <NUM>. In an alternative embodiment, the gas passage <NUM> formed may direct the gas flow to travel an angular rotation β about the centre <NUM> of the gas outlet (see <FIG> at <NUM>) of at least <NUM> degrees, at least <NUM> degrees or at least <NUM> degrees, relative to the gas inlet <NUM> before discharging at the gas outlet (see <FIG> at <NUM>).

<FIG> shows the noise reduction device <NUM> of the present disclosure being mounted to a respiratory apparatus <NUM>. The body <NUM> is mounted to one side of the respiratory apparatus <NUM> by the tabs <NUM> (see <FIG> at <NUM>). The tabs <NUM> (see <FIG> at <NUM>) on the cover <NUM> are oriented to be slidably locked with the corresponding slots <NUM>. A seal is to be formed by the first end portion <NUM> and the projection <NUM> of the guiding member <NUM> to define the gas passage <NUM>.

Referring to <FIG> which shows an embodiment of the components of the respiratory apparatus (see <FIG> at <NUM>) , it may further include a pressurized gas inlet <NUM> for supplying a pressurized gas, a chamber <NUM> in fluid communication with the gas outlet <NUM> (see <FIG> at <NUM>) of the noise reduction device (see <FIG> at <NUM>) and the pressurized gas inlet <NUM> wherein the chamber <NUM> is for mixing atmospheric air and the pressurized gas, and a noise-damping device <NUM> disposed downstream of the chamber <NUM>. The noise-damping device <NUM> is made of a porous material, for example, porous ceramic, porous plastics or porous polymeric foams, for absorbing noise in order to further minimize the noise generated when supplying a gas source to the respiratory apparatus.

It is believed that the noise reduction device <NUM> in the present disclosure can provide obvious noise reduction effect by decreasing the turbulence and resistance of gas flow to a larger extent and thus reducing the noise caused by the friction between the fluctuated gas flow and the gas inlet of the respiratory apparatus. Moreover, the configuration of the guiding member <NUM> being located on the cover <NUM> provides an easier and more convenient way to clean the gas passage <NUM>. The cover <NUM> can be disengaged from the body <NUM> and subject to common sterilization methods of medical equipment. Such arrangement also facilitates replacement of the cover <NUM> in case abrasion or damage is found on the guiding member <NUM> which may increase turbulent flow of the incoming gas and thus causes noise.

Claim 1:
A noise reduction device (<NUM>) for a respiratory apparatus (<NUM>), comprising:
a body (<NUM>) configured to be mounted on the respiratory apparatus (<NUM>), the body (<NUM>) comprising a side wall (<NUM>) and a gas outlet (<NUM>); and
a cover (<NUM>) configured to be detachably engageable with the body (<NUM>) for forming a gas inlet (<NUM>) and a gas passage (<NUM>), wherein the cover (<NUM>) comprises a guiding member (<NUM>) defining at least a part of the gas passage (<NUM>), wherein the guiding member (<NUM>) is configured to be coupled with the side wall of the body (<NUM>) to form the gas passage (<NUM>) between the body (<NUM>) and the cover (<NUM>), and wherein the gas passage (<NUM>) formed directs a flow of gas to an angular rotation about a centre of the gas outlet (<NUM>) of at least <NUM> degrees to <NUM> degrees relative to the gas inlet (<NUM>) before discharging at the gas outlet (<NUM>);
characterized in that the noise reduction device (<NUM>) further comprises:
a locking mechanism (<NUM>) for slidably locking the cover (<NUM>) to the body (<NUM>), wherein the locking mechanism (<NUM>) comprises at least two corresponding tabs (<NUM>) arranged on the cover (<NUM>), and at least two slots (<NUM>) respectively arranged on substantially diametrically opposite sides of the side wall (<NUM>) for complementary slide locking with the corresponding tabs on the cover (<NUM>),
and wherein the cover (<NUM>) is engaged with the body (<NUM>) to form the gas inlet (<NUM>) and the gas passage (<NUM>) by that the at least two corresponding tabs (<NUM>) arranged on the cover (<NUM>) are slidably locked to the at least two slots (<NUM>) arranged on the body (<NUM>) respectively.