GB2238480A - Breathing apparatus stowage - Google Patents

Abstract

A stowage container 1, 4 for an emergency breathing apparatus has a seal 2, 3 which is only openable by actuation of an initiation means 5 if an electrical, compressed gas or other energy source 17 for moving breathable gas is functional. As shown a smoke hood 13 is stowed in the container 1, 4 which is evacuated through a valve 11 for stowage in an aircraft. Actuation of the initiation means 5 perforates an oxygen cylinder 17 to inflate the hood and release the vacuum to permit opening of the container. Preferably (Fig 3) the gas source has a first cylinder 17 for initial purging of the hood connected by a capillary 52 to a second cylinder 53 for subsequent gas supply while the hood is worn. Alternatively an electric fan circulates filtered ambient air through a CO2 absorber. <IMAGE>

Description

BREATHING APPARATUS This invention relates to breathing apparatus, particularly for aircraft passengers.

Fires may occur in domestic, office, hotel or other premises and in ships. In all fires there is a mixture of smoke and hot toxic gases. A very wide range of toxic substances is present in fires occurring in aircraft. These arise from kerosene or other fuel and from a high proportion of synthetic plastics which are used in structures and furnishings. The number and type of toxic substances depends upon many factors including the material burning, fire temperature and the degree of pyrolysis and combustion, partial or complete.

It is well known in breathing apparatus to have a filter to remove smoke and toxic gases and some types of breathing apparatus, in open circuit mode, filter hot ambient air. It is also known to have a rebreathing system in closed circuit mode with independent oxygen supply, from a pressurised or chemical source, and to permit rebreathin with absorption of carbon dioxide by means of an absorber. Both types of breathing apparatus, filter and breathable gas, may be combined in a hybrid system. It is also known to coat material with semiconductor or other layers to reflect radiant heat.

It is also known to permit expansion of a reservoir (GB1034359) when the lid of a box is opened; to switch on a gas supply (GB1034359, GB878119) when a box is opened and to store a part of a breathing apparatus (GB2150838A) in a rupturable container which is ruptured or opened by release of gas from a reservoir.

Public reference to this method was made at the Farnborough International Air Show in September 1988. However, means are not described either to have the entire apparatus in a stowage container which is opened in this way or to provide a required flow profile from the opening of a single gas container or to describe a release means for such a fail safe device.

OXYGEN SOURCE A requirement of all safety equipment is that it should be fail safe but this is not easy to ensure with an oxygen source. This can however be achieved if the smoke hood container is opened by activation of the source. Another problem is to ensure that some oxygen is provided quickly to fill or purge the hood and that more is provided slowly to meet the needs of respiration over an extended period. Methods of doing these are described.

FILTERS Filters may be flat, used without an oronasal mask, or cylindrical and used with an oronasal mask. The former are advantageous in that they have light weight, large surface area and low breathing resistance but disadvantageous because of large dead space and rise of carbon dioxide from exhaled gas. The latter have the opposite advantages and disadvantages.

CIRCULATION The circulation of gas in breathing apparatus is usually by respiratory action or release of pressurised gas but a motorised fan which uses electrical energy may be required.

INVENTION According to the present invention there is described, by way of example only, breathing apparatus for aircraft passengers and others comprising: Combined breathing apparatus and stowage means therefor, said stowage means containing said breathing apparatus therein, said breathing apparatus having breathable gas source and conveyance means, which conveys said breathable gas to respiratory passages of user, circulation means, which circulates gas in said conveyance means as required by mode of operation, said stowage means including seal means, further including initiation means which in use causes release of power from a single commodity only when said breathing apparatus is functional, and in such instance permits said breathing apparatus to be removed from said stowage means by opening of said seal means and in said combination is fail safe.

Thus the breathing apparatus provides: a) means for stowage of smoke hood which is fail safe; b) means for supplying pure oxygen or filtered air to a user; c) means for conveying respiratory gases to a user; d) means for circulating gas within or from a hood; e) means for initiating release of power to open seal means.

In the present invention provision is made for stowage of the breathing apparatus. The supply source is pure oxygen or filtered ambient air. A motor pump may be used to control the internal hood environment and in particular to remove waste gases from the environment by circulating gas through a carbon dioxide absorber or by exhausting waste gases from hood to ambient. Radiant heat protection is provided.

A fail safe stowage container works on the principle that a commodity, essential for effective function of the breathing apparatus, provides also the power used to open the stowage container. Thus, for example, a compressed oxygen source provides oxygen as the essential breathable gas for the user and the power of oxygen under pressure is used to open the container.

Alternatively, in a system which provides breathable gas by filtration of ambient air and which requires a motor, electrical energy is necessary to power the motor and is also used to open the container.

According to the present invention there is provided breathing apparatus with breathable gas source, conveyance means, seal means, circulation means and stowage means with initiation means to releases power from a commodity which is essential, firstly, for the effective function of said apparatus and, secondly, for providing means for opening said container. Different initiation means are required for gas and electrical power.

In one embodiment of the invention breathable gas source, circulation means and commodity are all compressed oxygen. The OXygen source according to the invention is contained in a double chamber which provides initial rapid and later slow gas flow.

In another, for use in closed circuit mode, there is an oxygen source, a conveyance means comprising a hood, a carbon dioxide absorber and a motor which circulates gas in hood through said carbon dioxide absorber.

In another, breathable gas source is filtered air, circulation means is a motor and commodity is electrical energy stored in a battery which also drives said motor. The motor may circulate exhaled gas through a carbon dioxide absorber or it may exhaust it to ambient.

The stowage means according to the invention may include a flexible membrane which, allows for gas expansion so that container seal is not affected by change of ambient pressure, and a port means to evacuate stowage means or to test pressue or power source within it.

The conveyance means of the invention may have a heat reflective coating to protect the user from radiant heat.

All diagrams are schematic.

Figure 1 shows a sealed smoke hood container.

Figure 2 shows a smoke hood.

Figure 3 shows the detail of oxygen supply source.

Figure 4 shows detail of electrical initiation means.

In Figure 1 is shown base 1 of a stowage container which is fixed to a seat back. It has a cup shaped rim 2 which fits onto the edge 3 of a snap on lid 4 which contains a press button release means 5 and has small perforations 6 in the front. At the lower end is a hinge 7 with struts 8 and 9 attached respectively to the lid 4 and base 1. At the top end is a port 10 containing a valve 11. Inside the container lid 4 is a flexible rubber membrane 12 and inside the container base 1 and lid 4 is a smoke hood 13.

Inside the hood 13 is a plate 14 on which is mounted a spike or perforator means 15 which is prevented from coming into contact with the cap 16 of an oxygen cylinder 17 by a spring 18. The base 19 of the cylinder 17 is close to the button 5 but separated from it by the membrane 12 and hood 13. The port 10 is used to insert a suction tube through the valve 11 to exhaust air after the lid 4 has been placed on the base 1 of the container and to insert a pressure manometer to confirm that no gas has leaked out from source or in from ambient air or to test power of power source or commodity. When the button 5 is pressed the base 19 pushes the cylinder 17 forward to compress the spring 18, perforate the cap 16 and release gas to open the container by increase of pressure.

The space between lid 4 and membrane 12 allows for expansion of gas inside stowed hood when aircraft is at altitude.

In Figure 2 is shown a hood 13 with neck seal 21, oxygen cylinder 17, motor 22 and filter 23. Also required, but not shown in figure, is a power supply for motor such as electrical or other energy stored in a battery or otherwise.

In Figure 3 is shown cylinder 17 with cap 16 connected by junction means 51 containing capillary tube 52 to second oxygen cylinder 53 with base 54 which corresponds to base 19 of cylinder 17 in Figure 1. This arrangement ensures that oxygen is delivered quickly from first cylinder 17 but slowly from second cylinder 53 with the rate of flow being controlled by the diameter and length of the capillary tube 52 and by the pressure difference between the interiors of the cylinders and ambient.

In Figure 4 is obturator 30, of same size and position as cylinder 17 of Figure 1, with conductor 31 and conducting plate 14 and projection 32 separated by non conducting spring 18. Wires 33 and 34 are connected to switch 35 which switches on battery 36 to drive fan 37 when circuit is closed by bringing projection 32 into contact with conductor 31.

It will be apparent to those skilled in the art that changes may be made in the shape, design and material composition of the apparatus, in the number, configuration and arrangements of the components thereof and that a variety of manufacture methods, of types, of sizes and of devices may be used. The container may be vented by an electrically operated valve with a functional power source as a necessary condition for activation. A simple filter may be fitted with an oxygen supply to supplement low ambient oxygen.The container may be located overhead or elsewhere; an indicator light may be lit when the container is opened; the container may be opened automatically or by activation of initiation means, electro mechanical or gas pressure or other mechanism, in response to local action or remote signal from cabin or flight deck by staff or others; decompression protection may be combined with smoke hood provision and suitable instructions may be broadcast and fixed to the case. The apparatus may be used as or in conjunction with a simple pure oxygen source, a switchable carbon dioxide absorber, a simple or a motorised filter. A venturi effect might be preferred to a motor. The advantages of both systems may be obtained in a hybrid system using pure oxygen as an oxygen source in a rebreathing system or clean air in an open circuit system.Thus, the system may be used with open circuit oxygen when oxygen is released directly into the hood. It may be used with closed circuit oxygen when oxygen is released into the hood and gas from the hood is pumped from hood to absorber and back to hood. It may be used in a system which provides breathable gas by filtration of ambient air and which requires a motor to circulate or exhaust gas.

It will also be obvious to those skilled in the art that the apparatus illustrated, the methods suggested and the possibility for ancillary apparatus are given by way of example only and do not exclude the many other methods or possibilities which are obvious for such breathing apparatus or ancillary apparatus. It will also be apparent to those skilled in the art that such apparatus may be used in warfare, in an industrial environment and in hotel, shop, office and house fires. It may be used by armed forces, firemen, miners, sewage workers, civilians and others during chemical warfare, fires and other emergencies in aircraft, ships and buildings.

Claims (10)

1) Combined breathing apparatus and stowage means therefor, said stowage means containing said breathing apparatus therein, said breathing apparatus having breathable gas source and conveyance means, which conveys said breathable gas to respiratory passages of user, with circulation means, which circulates gas in said conveyance means as required by mode of operation, said stowage means including seal means, further including initiation means which in use causes release of power from a commodity only when said breathing apparatus is functional, and in such instance permits said breathing apparatus to be removed from said stowage means by opening of said seal means and in said combination is fail safe.

2) Combined breathing apparatus and stowage means according to claim (1) in which said breathable gas source and said commodity are both compressed gas delivered to interior of said conveyance means and in which said circulation means is also said compressed gas, said compressed gas is contained in container means, in which said container means has two chambers with interconnecting capillary tube and a cap at end, such that opening said cap provides initial rapid gas flow from proximal chamber and later slow gas flow from distal chamber.

3) Combined breathing apparatus and stowage means according to claim (2) for use in closed circuit mode in which said breathable gas is pure oxygen, said conveyance means comprises a hood, further including a carbon dioxide absorber and said circulation means is chosen from a motor and respiratory action of the user.

4) Combined breathing apparatus and stowage means according to claim (3) including rebreathing bag.

5) Combined breathing apparatus and stowage means according to claim (1) in which said breathable gas source is ambient air enabled by a filter, said circulation means is said motor and said commodity is electrical energy, held in a storage device.

6) Combined breathing apparatus and stowage means according to claim (6) for use in open circuit mode with said filter, and in which said conveyance means comprises said hood and said motor circulates gas from said hood to ambient.

7) Combined breathing apparatus and stowage means according to claim (1) and having said sealable stowage means in which a port allows insertion of apparatus to extract gas from interior of said stowage means to prevent break of said seal at altitude.

8) Combined breathing apparatus and stowage means according to claim (7) in which said port allows insertion of apparatus to test pressure within said stowage means.

9) Combined breathing apparatus and stowage means according to claim (7) in which said port allows insertion of apparatus to test said power source.

10) Combined breathing apparatus and stowage means according to claim (1) and having said sealable stowage means in which a flexible membrane allows for gas expansion so that said seal of said stowage means is not affected by change of ambient pressure.