CN114558257A

CN114558257A - Automatic opening suction valve for emergency escape breathing equipment

Info

Publication number: CN114558257A
Application number: CN202210136223.5A
Authority: CN
Inventors: 马闯; K.陆; B.刘
Original assignee: Honeywell International Inc
Current assignee: Honeywell International Inc
Priority date: 2015-11-13
Filing date: 2015-11-13
Publication date: 2022-05-31
Anticipated expiration: 2035-11-13
Also published as: CN108472519B; CN114558257B; WO2017079967A1; CN108472519A

Abstract

The invention relates to an automatic opening suction valve for emergency escape breathing equipment. An inhalation valve for use with an emergency escape breathing apparatus (EEBD) is provided. EEBD may be used in emergency situations to protect users from smoke, chemicals, particles or other harmful elements in the air and to provide breathable air to users. The EEBD (100) may include an air cylinder (104), a shroud (102), and a hose (106) that provides air from the cylinder (104) to the shroud (102). The EEBD (100) may also include a suction valve (108) attached to the hose (106).

Description

Automatic opening suction valve for emergency escape breathing equipment

The application is a divisional application of an invention patent application with the application date of 2018, 7 and 12 months and the application number of 201580085712.0 and the name of 'automatic opening suction valve for emergency escape breathing equipment'.

Technical Field

The invention relates to an automatic opening suction valve for emergency escape breathing equipment.

Background

Emergency respirators may be worn during an emergency to protect the user from harmful substances in the air. Emergency respirators may be worn in either a working environment or a residential environment. Some emergency respirators may have a breathable air tube for a user to breathe when escaping the hazardous environment.

Disclosure of Invention

Aspects of the present disclosure may include embodiments of a suction valve for use with a shroud, the suction valve comprising: a valve seat, wherein the valve seat fits within the opening of the cover; a cover operable to attach to the valve seat, wherein the cover is located in the interior of the cage, and wherein a portion of the cage is secured between the valve seat and the cover; a hose operable to provide breathable air to an interior of the kit, wherein the hose is attached to the valve seat; a flexible membrane operable to move in response to pressure within the suction valve, wherein the flexible membrane closes when air flows through the hose, wherein the flexible membrane opens in response to a user's inhalation when no air flows through the hose, wherein the valve seat comprises an opening to allow ambient air to pass through the valve when the flexible membrane opens, and wherein the cover comprises a slot to allow air to enter the interior of the housing.

In some embodiments, the hose passes through the center of the valve seat. In some embodiments, the hose and valve seat are heated to attach the hose to the valve seat. In some embodiments, the suction valve may further include a filter operable to cover the opening of the valve seat and filter outside air passing through the suction valve to the interior of the hood. In some embodiments, the filter is retained within the valve seat by detents on the valve seat. In some embodiments, a portion of the flexible membrane is attached to a groove in the valve seat. In some embodiments, the cap comprises threads, wherein the valve seat comprises threads, and wherein the cap is threaded onto the valve seat. In some embodiments, the suction valve, hood, and hose are part of an emergency escape breathing apparatus (EEBD). In some embodiments, when air flows from the hose into the valve, the flexible membrane seals against a portion of the valve seat, thereby preventing ambient air from entering the valve via the opening in the valve seat.

Additional aspects of the present disclosure may include embodiments of an EEBD comprising a cartridge containing a limited amount of breathable air; a hood operable to fit over a user's head and seal around the user's neck; a hose operable to provide breathable air from the cartridge to the interior of the mask; a suction valve attached to the hose, the suction valve including a valve seat, wherein the valve seat fits within the opening of the shroud; a cover operable to attach to the valve seat, wherein the cover is located in the interior of the cage, and wherein a portion of the cage is secured between the valve seat and the cover; a flexible membrane operable to flex in response to pressure within the suction valve, wherein the flexible membrane seals against a portion of the valve seat when air flows from the hose into the valve, thereby preventing ambient air from entering the shroud, wherein when no air flows from the cartridge through the hose, the flexible membrane will flex away from the valve seat in response to a user's inhalation, allowing ambient air to enter the shroud via an opening in the valve seat, and wherein the cover comprises a groove that allows air to enter the interior of the shroud via the suction valve.

In some embodiments, the hose passes through the center of the valve seat. In some embodiments, the suction valve further comprises a filter operable to cover the opening of the valve seat and filter outside air passing through the suction valve to the interior of the hood. In some embodiments, the suction valve comprises a circular shape. In some embodiments, the cap comprises threads, wherein the valve seat comprises threads, and wherein the cap is threaded onto the valve seat. In some embodiments, the cover is dome-shaped to direct air flowing from the hose onto the flexible membrane to seal the flexible membrane against the valve seat.

Other aspects of the present disclosure may include embodiments of a method for assembling an intake valve for use with an EEBD, the method comprising: providing a hose operable to supply breathable air from the cartridge to the hood of the EEBD; attaching a hose to a valve seat of a suction valve; attaching a flexible membrane to the valve seat, wherein the valve seat comprises an opening, wherein the flexible membrane seals the opening, and wherein the flexible membrane is operable to flex away from the opening in response to a negative pressure within the enclosure; and attaching the valve seat to the cover by threadably connecting the cover to the valve seat, wherein a portion of the cover is secured between the valve seat and the cover.

In some embodiments, attaching the hose to the valve seat may include heat staking the hose to the valve seat. In some embodiments, attaching the flexible membrane to the valve seat may include securing a portion of the flexible membrane within a groove on the valve seat. In some embodiments, the method may further comprise providing a filter operable to fit within the valve seat and filter any air that enters the cover through the valve seat. In some embodiments, the cover may be located on the interior of the enclosure, and the cover may include a slot that allows air to pass through the enclosure into the interior of the enclosure.

These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.

Drawings

For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

FIG. 1 illustrates an EEBD according to an embodiment of the present disclosure;

FIG. 2 shows an exploded view of a suction valve according to an embodiment of the present disclosure;

FIG. 3 illustrates a cross-sectional view of a suction valve according to an embodiment of the present disclosure;

FIG. 4A illustrates another cross-sectional view of a suction valve according to an embodiment of the present disclosure;

FIG. 4B illustrates another cross-sectional view of a suction valve according to an embodiment of the present disclosure;

FIG. 5 shows a detailed view of a cover according to an embodiment of the present disclosure; and

6A-6C illustrate detailed views of a valve seat according to an embodiment of the present disclosure.

Detailed Description

It should be understood at the outset that although illustrative implementations of one or more embodiments are illustrated below, the disclosed systems and methods may be implemented using any number of techniques, whether currently known or not yet existing. The present disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, but may be modified within the scope of the appended claims along with their full scope of equivalents.

The following brief definitions of terms shall apply throughout the application:

the term "comprising" means including but not limited to, and should be interpreted in the patent context in the manner normally used;

the phrases "in one embodiment," "according to one embodiment," and the like generally mean that a particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the invention, and may be included in more than one embodiment of the invention (importantly, such phrase does not necessarily refer to the same embodiment);

if the specification describes something as "exemplary" or "an example," it should be understood to mean a non-exclusive example;

the terms "about" or "approximately" and the like, when used with a number, may mean the particular number, or alternatively, a range that is close to the particular number, as understood by those skilled in the art; and

if the specification states that a component or feature "may (may)", "may (can)", "may (result)", "should (short)", "will (child)", "preferably (preferably)", "possibly (availability)", "typically (typically)", "optionally (optional)", "for example (for example)", "often (in)" or "possibly (light)" (or other such language) includes or has a feature, that particular component or feature is not required to include or have that feature. This component or feature may optionally be included in some embodiments, or may be excluded.

Embodiments of the present disclosure include an inhalation valve for use with an emergency ventilator or EEBD. These EEBDs are respirators that can be used in emergency situations to protect the user from smoke, chemicals, particles or other harmful elements in the air and to provide breathable air to the user. For example, in the event smoke, dust and other harmful substances may be in the air, the EEBD may be worn by a user escaping a fire or other emergency. The EEBD may include an air cylinder, a hood, and a hose that provides air from the cylinder to the hood. Typically, EEBD may be capable of providing approximately 10-15 minutes of breath, depending on the volume of the cartridge. When the air is exhausted or used up, the user must either immediately remove the hood or risk choking due to lack of oxygen within the hood.

The hood may be difficult to remove quickly because the hood seals around the neck of the user (to prevent harmful substances from entering the hood). Furthermore, if the user is escaping the hazardous environment, it can be problematic to spend time and effort to remove the cover. If the user is still in a hazardous environment when they must remove the mask, the user's face, eyes and head may be affected by the hazardous substances. Additionally, if the user is in an emergency, the user may be strained and/or injured, making it difficult for the user to remove the cover, resulting in a choking potential. Furthermore, the user wearing the EEBD may not be trained in using the EEBD, and thus removing the cover may be difficult.

The applicant has developed a suction valve for use on an EEBD that addresses these concerns. The suction valve may be closed when the cartridge provides air to the hood. In some embodiments, the pressure from the air supplied from the cartridge may keep the suction valve closed, and the suction valve may not require any other elements to keep the valve closed while still having air supplied from the cartridge.

When the cartridge is depleted of air and no longer supplies air to the mask, the inhalation valve may open, allowing the user to continue breathing while wearing the mask. This may allow the user to continue wearing the mask even when the cartridge is depleted of air. In some embodiments, the valve may also have a filter operable to filter ambient air entering the hood through the suction valve. The addition of a suction valve to the mask reduces the likelihood of choking when the mask is worn. In addition, the user may continue to wear the mask, thereby protecting the user's head, eyes, and face.

Referring now to FIG. 1, an exemplary embodiment of an EEBD100 is shown. The EEBD100 may include a hood 102, the hood 102 operable to fit over a user's head. The shroud 102 may include a seal 110 around the neck of the user, wherein the seal 110 may prevent outside air from entering the shroud 102. Further, the EEBD100 may include a canister 104 of breathable air, wherein the breathable air is supplied from the canister 104 to the hood 102 via a hose 106. In some embodiments, a hose 106 may be attached to the rear of the shroud 102. In other embodiments, the hose 106 may be attached at any other point on the shroud 102.

In some embodiments, the shroud 102 may include a suction valve 108. The cartridge 104 may contain a limited amount of breathing air. When the cartridge 104 is exhausted, the inhalation valve 108 may automatically open to allow the user to breathe without having to remove the mask 102. In some embodiments, the inhalation valve 108 may comprise a filter operable to filter ambient air for user breathing.

Referring now to FIG. 2, an exemplary embodiment of a suction valve 200 is shown. The suction valve 200 may be attached to a shroud (similar to the suction valve 108 shown in fig. 1). The suction valve 200 may include a valve seat 202, wherein the valve seat 202 may be attached to a hose 206 (similar to the hose 106 in fig. 1). The hose 206 may be part of the EEBD and may provide breathable air from the cartridge, as described in fig. 1.

In some embodiments, the hose 206 and the valve seat 202 may comprise materials that can be heated and fused (or hot pressed) to each other to attach the hose 206 to the valve seat 202. For example, the hose 206 may comprise a rubber material and the valve seat 202 may comprise a plastic material. When the hose 206 and valve seat 202 are heated, these materials may partially melt and seal against each other. In other embodiments, an adhesive may be used to attach the hose 206 and the valve seat 202. In another embodiment, another accessory may be used to attach the hose 206 and the valve seat 202. In another embodiment, the hose 206 may be mounted on the valve seat 202 by a clamp.

In some embodiments, the suction valve 200 may include a cover 204 attached to a valve seat 202. In some embodiments, the valve seat 202 may include threads 212 and the cover 204 may include threads 216, allowing the cover 204 to be threaded onto the valve seat 202. In another embodiment, the valve seat 202 and the cover 204 may include a snap, hook, or another attachment mechanism. In some embodiments, the cover 204 may be located inside the housing, while at least a portion of the valve seat 202 may be located outside the housing. The cover 204 and the valve seat 202 may be attached to each other through an opening in the cover. In some embodiments, the cover 204 may include an opening or slot 214 to allow air to pass through the cover 204 into the interior of the enclosure.

In some embodiments, the valve 200 may include a flexible membrane 208, wherein the flexible membrane 208 may be retained within a groove 209 in the valve seat 202. The inner edge 207 of the flexible membrane 208 may be retained within the groove 209, allowing the remainder of the membrane 208 to flex in response to pressure within the valve 200. In some embodiments, the valve seat 202 may include an opening 203, which may be located adjacent to the flexible membrane 208. In some embodiments, the valve 200 may include a filter 210, which may be retained within the valve seat 202. In some embodiments, air may pass through filter 210 and through opening 203, move flexible membrane 208, and also through slot 214 in cover 204 to access the interior of the enclosure. In some embodiments, the valve 200 may comprise a circular shape, but in other embodiments, the shape of the valve may be oval, rectangular, square, or any other shape.

Referring now to FIG. 3, a cross-sectional view of the valve 200 is shown. As described above, the cover 204 may be threaded onto the valve seat 202 (via threads 212 and 216). A portion of the bonnet 102 may be retained between the bonnet 204 and the valve seat 202, securing the valve 200 to the bonnet 102. In some embodiments, the cover 204 may be located inside the housing, while at least a portion of the valve seat 202 may be located outside the housing. The cover 204 and the valve seat 202 may be attached to each other through an opening in the cover. In some embodiments, the cover 204 may include an opening or slot 214 to allow air to pass through the cover 204 into the interior of the enclosure.

In some embodiments, the valve seat 202 may include a protrusion 205, wherein the cover 102 may be secured between the cover 204 and the protrusion 205 of the valve seat 202. In some embodiments, the valve seat 202 may include one or more detents 220 operable to hold the filter 210 in place within the valve seat 202. The inner edge 207 of the flexible membrane 208 may be held in place in the groove 209 of the valve seat 202. In some embodiments, the flexible membrane 208 may contact and seal with a portion of the valve seat 202. However, the flexible membrane 208 is also operable to flex toward the cover 204 while the inner edge 207 of the membrane 208 remains in place in the slot 209. In some embodiments, the slot 214 of the cover 204 may be located adjacent to the flexible membrane 208. In some embodiments, a portion of the hose 206 may extend through the valve seat 202 into the cover 204.

Referring now to FIG. 4A, another cross-sectional view of the valve 200 is shown. In the embodiment shown in fig. 4A, the hose 206 may supply breathable air 320 into the interior 302 of the mask 102. Air 320 may enter the cap 204 of the valve 200 through the hose 206. The air 320 may then exit the lid 204 via the slot 214 in the lid 204. In the illustrated embodiment, the air 320 may create pressure that pushes the flexible membrane 208 against the valve seat 202. In other words, air 320 flowing through the hose 206 and the cap 204 may "close" the valve 200, not allowing any air to pass through the valve seat 202 and/or the opening 203 in the flexible membrane 208. When the EEBD has a sufficient supply of air from the cartridge, the air flow 320 may continue through the hose 206.

Referring now to FIG. 4B, another cross-sectional view of the valve 200 is shown. In the embodiment of fig. 4, the air supplied by the hose 206 from the cartridge may have been exhausted or may have been exhausted. Thus, pressure on the flexible membrane 208 may be removed, allowing the membrane 208 to "open" inward toward the lid 204. As the user breathes, creating a negative pressure on the interior 302 of the mask 102, the flexible member 208 may flex away from the valve seat 202, allowing air 420 to pass through the opening 203 in the valve seat 202 and through the slot 214 in the cover 204 into the interior 302 of the mask 102. In some embodiments, the air 420 may pass through the filter 210, wherein the filter 210 is operable to remove harmful particulates and/or chemicals from the air 420 before the air 420 enters the interior 302 of the shroud 102.

In some embodiments, the flexible membrane may comprise any flexible material that is gas impermeable. For example, the flexible membrane may comprise a plastic material, a rubber material or any kind of flexible rubber, such as Ethylene Propylene Diene Monomer (EPDM), Nitrile Butadiene Rubber (NBR) and Natural Rubber (NR).

In some embodiments, the filter may include any filter material operable to filter harmful particulates and/or chemicals from the air. The filter is operable to filter smoke, dust and other harmful substances. For example, the filter material may include polypropylene (PP) meltblown, Polyethylene (PET) nonwoven, glass fiber nonwoven, and the like.

Referring now to fig. 5, a detailed view of the cover 204 is shown. In some embodiments, the plurality of slots 214 may extend around the entire circumference of the cover 204. The cap 204 may also include threads 216 for attaching the cap 204 to a valve seat. In some embodiments, the threads 216 may be located below the slots 214. In some embodiments, the cover 204 may be dome-shaped to direct air flowing from the hose 206 onto the flexible membrane 208 to seal the flexible membrane 208 against the valve seat 202 (as shown above).

Referring now to fig. 6A-6C, detailed views of the valve seat 202 are shown. Fig. 6A shows a side view of the valve seat 202. Fig. 6B shows a bottom orthogonal view of the valve seat 202. Fig. 6A shows a cross-sectional view of the valve seat 202 and filter 210.

The valve seat 202 may include an opening 600 for receiving a hose, wherein, in some embodiments, the opening 600 may pass through the center of the valve seat 202. The valve seat 202 may include threads 212 for attaching the valve seat 202 to a cover. In some embodiments, the valve seat 202 may include a protrusion 205. In some embodiments, the valve seat 202 may include one or more openings 203 extending through the valve seat 202. In some embodiments, the valve seat 202 may include a groove 209 for retaining a portion of the flexible membrane. In some embodiments, the valve seat 202 is operable to retain the filter 210, wherein the filter 210 may fit within the valve seat 202, held in place by one or more detents 220. In some embodiments, filter 210 may cover opening 203 such that any air passing through opening 203 must also pass through filter 210. In some embodiments, filter 210 may include an opening 602 for fitting around a hose, where opening 602 may be similar to opening 600. In some embodiments, filter 210 may comprise a flexible and/or compressible material, wherein filter 210 may be easily positioned within valve seat 202.

Some embodiments of the present disclosure may include a method for assembling an intake valve for use with an EEBD. A hose may be provided, wherein the hose is operable to supply breathable air from the canister to the hood of the EEBD. The hose may be attached to a valve seat of the suction valve. In some embodiments, attaching the hose to the valve seat may include heat staking the hose to the valve seat. A flexible membrane may be attached to the valve seat, wherein the valve seat includes an opening, wherein the flexible membrane seals the opening, and wherein the flexible membrane is operable to flex away from the opening in response to a negative pressure within the enclosure. In some embodiments, attaching the flexible membrane to the valve seat may include securing a portion of the flexible membrane within a groove on the valve seat. The valve seat may be attached to the cover by threadably connecting the cover to the valve seat, wherein a portion of the cover is secured between the valve seat and the cover.

In some embodiments, the method may further comprise providing a filter operable to fit within the valve seat and filter any air that enters the cover through the valve seat. In some embodiments, the cover may be located on the interior of the enclosure, and the cover may include a slot that allows air to pass through the cover into the interior of the enclosure.

While various embodiments in accordance with the principles disclosed herein have been shown and described above, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the disclosure. The embodiments described herein are merely representative and are not intended to be limiting. Many variations, combinations, and modifications are possible and are within the scope of the disclosure. Alternative embodiments resulting from combining, integrating, and/or omitting features of one or more embodiments are also within the scope of the present disclosure. Accordingly, the scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims. Each claim is incorporated into the specification as a further disclosure, and the claims are examples of the present invention. Moreover, any advantages and features described above may relate to particular embodiments, but the application of the claims as issued should not be limited to processes and structures accomplishing any or all of the above advantages or having any or all of the above features.

Further, the section headings used herein are provided for consistency with the suggestions of 37c.f.r 1.77, or to otherwise provide organizational cues. These headings should not limit or characterize the invention(s) set forth in any claims that may issue from this disclosure. In particular and for example, although a title may refer to a "technical field," the claims should not be limited by the language chosen under this title to describe the so-called technical field. Further, the description of technology in the "background" should not be construed as an admission that certain technology is prior art to any invention in this disclosure. The summary of the invention is not to be considered a limiting feature of one or more inventions set forth in the issued claims. Furthermore, any reference in this disclosure to the singular "invention" should not be used to argue that there is only one point of novelty in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims issuing from this disclosure, and such claims accordingly define the invention(s) and their equivalents, which are protected thereby. In all cases, the scope of the claims should be considered in their own right in view of this disclosure, and not limited by the headings set forth herein.

The use of broader terms such as comprising, including and having should be understood to be narrower terms such as consisting of …, consisting essentially of … and consisting essentially of providing support. Use of the terms "optionally," "may," "might," and the like with respect to any element of an embodiment means that the element is not required, or is instead required, both alternatives being within the scope of one or more embodiments. Additionally, references to examples are provided for illustrative purposes only and are not intended to be exclusive.

While several embodiments are provided in the present disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented.

In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component, whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.

Claims

1. A suction valve (200), the suction valve (200) comprising:

a valve seat (202);

a cover (204) operable to attach to the valve seat (202);

a hose (206) operable to provide a breathable air pressure,

wherein the hose (206) is attached to the valve seat (202);

a flexible membrane (208) comprising a gas impermeable flexible material and configured to flex between an open position and a closed position in response to a pressure within the inhalation valve (200) caused by a pressure from the hose (206) or a negative pressure generated when a user breathes without pressure from the hose (206), an inner edge (207) of the flexible membrane (208) remaining within a groove (209) of the valve seat (202), allowing a remainder of the flexible membrane (208) to flex in response to the pressure within the inhalation valve (200),

wherein:

the flexible membrane (208) closes when air flows through the hose (206);

the flexible membrane (208) flexes open in response to negative pressure generated by inhalation by a user when no air flows through the hose (206);

the valve seat (202) comprises an opening (203) to allow ambient air to pass through the suction valve (200) when the flexible membrane (208) is open; and

the cover (204) includes a slot (214),

wherein the hose (206) passes through the center of the valve seat (202).

2. The suction valve (200) of claim 1, wherein the flexible membrane (208) comprises one or more of a plastic material, a rubber material.

3. An inhalation valve (200) according to claim 2, wherein the rubber material is Ethylene Propylene Diene Monomer (EPDM), Nitrile Butadiene Rubber (NBR) and Natural Rubber (NR).

4. The suction valve (200) of claim 1, further comprising a filter (210) operable to cover the opening (203) of the valve seat (202) and filter the ambient air passing through the suction valve (200).

5. The intake valve (200) according to claim 1, wherein the intake valve (200) and the hose (206) are part of an emergency escape breathing apparatus (EEBD) (100).

6. The suction valve (200) of claim 1, wherein the flexible membrane (208) seals against a portion of the valve seat (202) when air flows from the hose (206) into the valve, thereby preventing ambient air from entering the suction valve (200) via an opening in the valve seat (202).

7. An emergency escape breathing apparatus (EEBD) (100) comprising:

a cartridge (104) containing a limited amount of breathable air;

a hose (206) operable to provide breathable air pressure from the barrel (104);

a suction valve (200) attached to the hose (206),

the suction valve (200) comprises:

a valve seat (202);

a cover (204) operable to attach to the valve seat (202);

wherein:

the flexible membrane (208) seals against a portion of the valve seat (202) when air flows from the hose (206) into the suction valve;

when no air flows from the cartridge (104) through the hose (206), the flexible membrane (208) will flex away from the valve seat (202) in response to inhalation by a user,

allowing ambient air to enter via an opening (203) in the valve seat (202); and

the cover (204) includes a slot (214),

wherein the hose (206) passes through the center of the valve seat (202).

8. An emergency escape breathing apparatus (EEBD) according to claim 7, wherein said suction valve (200) further comprises a filter (210) operable to cover said opening (203) of said valve seat (202) and filter said ambient air passing through said suction valve (200).

9. An emergency escape breathing apparatus (EEBD) according to claim 7, wherein the cover (204) is dome-shaped to direct air flowing from the hose (206) onto the flexible membrane (208) to seal the flexible membrane (208) against the valve seat (202).