GB2365357A

GB2365357A - Hooded breathing apparatus

Info

Publication number: GB2365357A
Application number: GB0017739A
Authority: GB
Inventors: Joseph Anthony Griffiths
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-07-19
Filing date: 2000-07-19
Publication date: 2002-02-20
Also published as: GB0017739D0

Abstract

A hooded breathing apparatus 1 comprising a hood having an inflatable pad/chamber 17 at the rear which on inflation engages the wearers head and draws the oro-nasal mask 3 provided at the front of the hood into contact with the face to make a tight seal. The mask has an outlet including a one-way valve 6 through which the wearer's exhalate can be exhausted to the exterior of the hood and an inlet including a one-way valve 5 through which inhalate can be drawn into the mask from the hood when the wearers breaths in. The hood has a valve 15 connected, via a duct 16, to the gas supply 12 to the mask which is normally closed so no gas enters the inflatable pad but which can be opened to allow inflation. The hood may be completely transparent or made of fireproof material with a viewing window 2.

Description

<Desc/Clms Page number 1> Hooded Breathing Apparatus This invention relates to hooded breathing apparatus and more particularly to an emergency escape breathing apparatus /respirator (EEBA) also known as Emergency Life Support Apparatus (ELSA). EEBA is a hooded breathing apparatus which provides an escapee from a smoke filled environment with a supply of breathable gas for a limited period (usually 5/10 minutes) which should be sufficient to enable the escapee to breathe non-contaminated air for long enough to exit the building or environment which is on fire or to escape from a toxic or oxygen deficient atmosphere.

A known EEBA comprises a hood of one size which is dimensioned to fit most head sizes (5 h_95 th percentile). The hood is supplied with a supply of compressed air or similar breathable gas and it has an elastic neck seal at its base adapted to fit all neck sizes and operable to keep out contaminants. The breathable gas supply to the interior of the hood is arranged so that it can be directed over the inside surface of the front of the hood to reduce misting up. Additionally the inside surface of the hood can be treated to prevent this happening.

An oro-nasal mask is provided within the hood which fits over the wearer's nose and mouth, said mask having inlet valves to admit breathable gas supplied to the interior of the hood to the interior of the oro-nasal mask and an outlet valve which allows expirate from the wearerps nose and mouth to be exhausted to the exterior of the hood. There is however a problem with this solution because the oro-nasal

mask does not always make a tight fit with the wearer's face particularly when the wearer is moving (e.g. runnig, walking or climbing in an emergency situation) so CO, exhalate will leak out from the oro-nasal mask into the interior of the hood. AsC021sheavier than air, it will build up from the bottom of the hood to an unacceptable level at which the wearer will be breathing CO, rather than the required breathable gas. It is necessary therefore to find some way of tensioning the oro-nasal mask against the wearer's face so that the seal is maintained while the wearer is moving in an escape situation. A strap or straps which extend around the back of the wearer's head cannot be used as they get in the way during donning of the hood and they can make doffing of the hood difficult if they are tightly tensioned. The tension in the flexible material from which the hood is made could be used to press the oro-nasal mask onto the face but EEBA's are usually made in one generic size so the fit would not be good enough to make the required seal if the wearer had a very small head.

It is an object of the present invention therefore to provide a one-size hooded breathing apparatus which will fit all wearers and which 'includes means which enable an oro-nasal mask therein to maintain its seal with the wearer's face at all times and thereby avoid or substantially reduce CO, build up within the hood.

According to the invention there is provided a hooded breathing apparatus comprising a hood adapted to fit over the wearer's head to provide an enclosed space from which the wearer can inhale a breathable gas supplied thereto, an oro-nasal mask at the front of the hood having

an outlet including a one-way valve through which the wearer's exhalate can be exhausted to the exterior of the hood and an inlet including a one-way valve through which inhalate from said enclosed space can be drawn into the oro-nasal mask when the wearer breathes in, the hood also having inflatable means at the rear thereof operable on inflation to engage the rear of the wearer's head to draw the oro-nasal mask into contact with the wearer's face and make a seal therewith.

Preferably the breathing apparatus includes means to supply a proportion of the breathable gas supplied to the interior of the hood to inflate the inflatable means.

In the preferred embodiment, said supply means includes a manually operable valve which, on activation, diverts a proportion of said breathable gas to the inflatable means at the rear of the hood. Conveniently said valve is located adjacent the oro-nasal mask and in the region of the front of the hood and is normally biased to a closed position in which no breathable gas reaches the inflatable means.

In the preferred embodiment, the oro-nasal mask is attached to the interior of the front of the hood and the inflatable means is provided on the interior of the rear of the hood.

The inflatable means can take any convenient form such as a pad or annular chamber on the interior or exterior surface of the rear of the hood. Alternatively a portion of the rear of the hood can be double skinned to provide the inflatable pad or chamber. The hood can be

completely transparent or alternatively it can be made from a fireproof material with a viewing window therein.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a view of a hooded breathing apparatus of the present invention; and Figure 2 is a schematic view of the *interior of the hood shown in Figure Referring to the drawings there is shown an emergency escape breathing apparatus (EEBA) also known as an Emergency Life Support Apparatus (ELSA) which comprises a smoke hood 1 made from a fire resistant fabric material. The hood 1 has a window 2 therein to enable a wearer to see out of the hood. The hood can be made entirely of a transparent material if required. The hood has a bottom portion 7 with a neck seal 8 therein of known type to keep contaminants out.

A breathable gas such as compressed air is supplied to the interior of the hood via a flexible hose 12 from a pressurised container or bottle 10. The contents of the bottle are normal1y pressunised to between 2-3000 psi and supply breathable gas for a period of up to 10 minutes at a flow rate of say 35-40 litres per minute. The flow of the breathable gas from the bottle 10 is controlled by a known regulator 11. The hose 12 is connected to a fitting 13 mounted on the exterior of the hood which incorporates a biased valve 15 to be described in more detail hereafter.

An oro-nasal mask 3 having a one-way valve 5 on each side thereof allows breathable gas supplied to the interior of the hood 1 to be drawn into the oro-nasal mask 3 when the wearer breathes in. The oro-nasal mask 3 is secured to the front of the hood and also includes a one-way valve 6 which allows exhalate to be exhausted to the exterior of the hood. To assist in the oro-nasal mask making a good seal with the wearer's face, it is formed with a flexible cuff or seal 4 around its perimeter. Oro-nasal masks of this type are well known in other applications so further description thereof will not be given here.

If the breathing apparatus is to function correctly, the wearer win draw the breathable gas supplied to the interior of the hood 1 from the bottle 10 into the oro-nasal mask 3 through the inlet valves 5. On exhalation, most of the expirate containingC02 should pass out of the mask 3 through the outlet valve 6. The breathable gas supplied to the interior of the mask 3 should be directed over the visor or window 2 to reduce misting up.

If the apparatus is to function properly, it is important thatC02 exhaled out into the oro-nasal mask 3 does not leak back into the interior of the hood 1 otherwise it could build up from the bottom of the hood. It is important therefore that the cuff 4 should make a tight seal with the wearerl's face at all times. To achieve this, the hood 1 is provided at the rear thereof with inflatable means 17 in the form of an annular balloon or chamber 17 having a supply duct 16 thereto connected to the fitting 13 and the valve 15. The valve 15 is normally closed and breathable gas supplied from the bottle 10 cannot travel through the duct 16 but instead is admitted to the interior of the hood 1.

When the wearer puts the hood on, it is a loose fit which it must be if it is to be fitted over the wearer's head with ease. The wearer then positions the oro-nasal mask 3 in the required position over his or her nose and mouth and preferably uses a finger on the same hand that is holding the oro-nasal mask 3 in position to depress the valve 15 whereby breathable gas from the bottle 10 is diverted along the duct 16 to inflate the annular balloon 17. This causes the whole hood 1 and the visor 2 to move in the direction of arrow A which in turn causes the oro-nasal mask 3 to be drawn against the wearer's face so that the cuff 4 makes an airtight seal therewith. As soon as the balloon 17 has been inflated sufficiently for the cuff 4 to make its seal -with the wearer's face, the wearer can release pressure on the valve 15 which then closes and seals the inlet duct 16 so the balloon remains inflated. The breathable gas supplied from the bottle 10 can now pass directly *into the interior of the hood for breathing on demand.

It will be seen from the foregoing description that a very simple way of tensioning the oro-nasal mask 3 against the wearer's face is provided which is easy to use and efficient in operation. It also allows the wearer to fit the hood quickly which is essential in an emergency situation. Furthermore, it has the advantage that only one size of hood needs to be manufactured as it can be made to fit the wearer regardless of head size by varying the degree of inflation of the balloon 17.

Although an annular balloon 17 is illustrated in the drawings, it will be appreciated that the balloon could be in the form of a single pad or multiple'pads or alternatively the rear of the helmet could be double

skinned to provide one or more chambers which can be inflated to create the desired movement in the direction of arrow A.

Claims

Claims 1. Breathing apparatus comprising a hood adapted to fit over the wearer's head to provide an enclosed space from which the wearer can inhale a breathable gas supplied thereto, an oro-nasal mask at the front of the hood having an outlet including a one-way valve through which the wearer's exhalate can be exhausted to the exterior of the hood and an inlet including a one-way valve through which inhalate from said enclosed space can be drawn into the oro-nasal masek when the wearer breaths in, the hood also having inflatable means at the rear thereof operable on inflation to engage the rear of the wearer's head to draw the oro-nasal mask into contact with the wearer's face and make a seal therewith.
2. A breathing apparatus as claimed in claim 1 further comprising means to supply a proportion of the breathable gas supplied to the interior of the hood to inflate the inflatable means.
3. A breathing apparatus as claimed in claim 2 wherein said supply means includes a manually operable valve which, on activation, diverts a proportion of said breathable gas to the inflatable means at the rear of the hood.
4. A breathing apparatus as claimed in claim 3 wherein said valve is located adjacent the oro-nasal mask and in the region of the front of the hood and is normally biased to a closed position in which no breathable gas reaches the inflatable means.
5. A breathing apparatus as claimed in any preceding claim wherein the oro- nasal mask is attached to the interior of the front of the hood and the inflatable means is provided on the interior of the rear of the hood.
6. A breathing apparatus as claimed in any preceding claim wherein the inflatable means is a pad or annular chamber on the interior or exterior surface of the rear of the hood.

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7. A breathing apparatus as claimed in claim 6 wherein a portion of the rear of the hood is double skinned to provide the inflatable pad or chamber.
8. A breathing apparatus as claimed in any preceding claim wherein the hood is completely transparent.
9. A breathing apparatus as claimed in any of claims 1 to 7 wherein the hood has a viewing window therein.
10. A breathing apparatus as claimed in claim 9 wherein the hood is made from a fireproof material.
11. A breathing apparatus as claimed in any preceding claim wherein the breathable gas is supplied from an outlet on a pressurised container whose contents are at a pressure of 2000-3000 psi.
12. A breathing apparatus as claimed in claim I I wherein a regulator is fitted to the container outlet.
13. A hooded breathing apparatus substantially as herein described with reference to the accompanying drawings.