GB2220573A

GB2220573A - Respiratory protection assembly

Info

Publication number: GB2220573A
Application number: GB8913002A
Authority: GB
Inventors: David William Pike
Original assignee: Racal Panorama Ltd
Current assignee: Racal Panorama Ltd
Priority date: 1988-06-16
Filing date: 1989-06-06
Publication date: 1990-01-17
Anticipated expiration: 2009-06-06
Also published as: GB8814337D0; GB2220573B; GB8913002D0

Abstract

An assembly adapted to provide respiratory protection e.g. during evacuation of a person from the scene of an accident, or battlefield, in circumstances where the casualty's body or clothing has become contaminated with a substance which is harmful if inspired. The assembly includes a flexible bag 1 to accommodate the whole person and isolate him from the external environment. Within the bag the casualty wears a personal powered respirator comprising an impeller unit 10 delivering uncontaminated air to a hood 9 or other breathing interface means. The impeller unit 10 may be supplied with air from outside the bag, filtered (14) if necessary, through hoses 5 leading from inlets 4 in the wall of the bag. Alternatively, (Fig 4) his impeller unit 10 may draw filtered (14) air from inside the bag itself, with another impeller unit 15 delivering air into the bag from outside. Air leaves the bag through a filter 7, thereby protecting the attendants from the effects of the contaminant upon the casualty. <IMAGE>

Description

Respiratory Protection Assembly The present invention relates to respiratory protection assemblies.

More particularly, the invention is concerned with an assembly adapted to provide respiratory protection e.g.

during evacuation of a person from the scene of an accident, or battlefield, in circumstances where the casualty's body or clothing has become contaminated with a noxious vapour-releasing agent or other such contaminant which is harmful if inspired. In these circumstances it is necessary to protect not only the casualty himself from the effects of the contaminant upon his person but also those attending him. Depending on the circumstances in which'the contamination occurred it may also be necessary to protect the casualty from further quantities of airborne contaminant in the surrounding environment.

With this aim in view the present invention resides in a respiratory protection assembly comprising: a closable bag or like enclosure adapted to accommodate the whole person to isolate the same from the external environment; a hood or other breathing interface means adapted to be worn by a person within said enclosure to isolate the wearer's breathing passages from the environment within the enclosure, and having an outlet opening into the interior of the enclosure; inlet means in the wall of the enclosure to permit the admission of air from the external environment; means to permit the passage of air out from the interior of the enclosure through filter means for removing unwanted component(s) therefrom; and means for the forced circulation of air through said inlet and of uncontaminated air through said breathing interface means.

In a preferred embodiment, conduit means are provided to extend from said inlet to powered air-circulation means located within the enclosure and thence to the breathing interface means.

In use of an assembly according to the invention the occupant of the enclosure (casualty), wearing the aforesaid breathing interface means, is protected from the effects of any respiratory contaminant with which his body or clothing may have come into contact, which is contained by the enclosure. At the same time, other persons in the vicinity of the enclosure are protected from the effects of any such contaminant upon the casualty within the enclosure by the aforesaid filtration of air leaving the enclosure. Where necessary, additional filter means will be provided for removing any unwanted component(s) present in the air supplied to the casualty's breathing interface means.

In the preferred embodiment, the casualty may be provided with what amounts to a self-contained powered respirator within the enclosure, comprising a battery-powered electric motor-driven impeller unit connected to provide the flow of air to the inlet of his breathing interface means, the inlet to the impeller unit itself being connected to the external environment via said conduit means. Where protection from contaminants in the external environment is also required the necessary filter(s) may also be added to or made integral with the impeller unit - continuous protection can thus be afforded to the casualty by this same respirator when both outside and inside the enclosure, with appropriate connection/ disconnection of the impeller unit to the conduit means when the casualty enters/exits the enclosure.

In other embodiments, however, a similar impeller unit (or other air-circulation means) and/or filter means for the inspired air may be located in association with the inlet of the enclosure externally thereof.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a respiratory protection assembly in accordance with a preferred embodiment of the invention, shown as in use for the conveyance of a contaminated casualty; Figure 2 is a perspective view of the assembly of Figure 1; Figure 3 is a perspective view, on an enlarged scale, of the components of the assembly as worn by the casualty within the enclosure; and Figure 4 is a plan view of an alternative respiratory protection assembly in accordance with the invention.

Referring to the drawings, reference numeral 1 denotes generally a bag of flexible thermoplastics or other material of a size sufficient to accommodate comfortably the whole adult human person. The illustrated embodiment is formed as a flat tubular extrusion or blow-moulding, heat sealed or otherwise joined and sealed, and united with handle fittings 2 at each end. Alternative or additional handle fittings may be provided at the sides.

The material of the bag is preferably transparent overall, (or at least a transparent panel will be provided at a position corresponding to the face of an occupant), and is of course selected to be impervious to the agent or class of agents by which persons to be conveyed in the bag are assumed to be contaminated. A zip fastener 3, (providing a hermetic seal when closed), extends diagonally across substantially the full length of the bag 1, to facilitate entry and exit of a casualty into and out of the bag. At an intermediate position, air inlets 4 are provided in opposite side walls of the bag, each opening into a respective flexible air hose 5 extending within the inner volume of the bag and adapted for demountable connection to the occupant's impeller unit described below.Towards the foot of the bag an air outlet is formed as a series of perforations as indicated at 6, covered by a pad 7 of activated charcoal or other filtering medium selected for the agent by which the occupant is contaminated, and retained by a heat-sealed flap or panel 8 of the bag material.

Within the bag 1 the casualty wears a powered respirator of the kind most clearly shown in figure 3. This includes a hood 9 of a transparent, flexible thermoplastics which encloses the whole head and is sealed around the neck by an adjustable strap. This form of hood is illustrated as it is assumed that the casualty may have some form of injury which militates against wearing the close-fitting mask of a standard respirator, although in principle any known kind of breathing interface means which isolates the occupant's breathing passages from the environment within the bag 1 may be employed.The other major component of this respirator is a belt-mounted impeller unit 10 housing an electric motor-driven fan, powered from internal rechargeable or other batteries, to draw a continuous flow of air from the environment outside the bag 1 in through the hoses 5 and deliver the same through a flexible hose 11 into the hood 9. Within the hood, a flap of material 12 defines two channels to direct the incoming air upwardly and rearwardly over the head of the wearer and thence down over his face to a pair of oneway outlet valves 13. The casualty is thus provided with a constant supply of fresh air to meet his breathing needs, the flow across his face serving both to keep the inside of the hood 9 free of mist and to flush out expired C 2 through the valves 13.The delivery of the impeller unit 10 is sufficient to maintain a positive pressure differential between the inside of the hood 9 and the interior of the bag 1 throughout the whole respiratory cycle of the user, to maintain the hood inflated at all times and prevent any risk of contaminated air leaking in around the neck seal.

In the illustrated embodiment the supply of air delivered to the hood 9 is also filtered through canisters 14 connected to the impeller unit 10, which contain activated charcoal or other filtering medium selected for an airborne contaminant which is assumed to exist in the environment outside the bag 1. In other circumstances, however, where the occupant has himself become contaminated but there is no general environmental contamination, these filters may be omitted and the hoses 5 connected directly into the inlets of the impeller unit 10.

The airflow passing out of the hood 9 through the valves 13 of course passes into the interior of the bag 1. When the system is connected up and the bag first closed this flow from the hood into the bag will cause a certain initial inflation of the bag until the resistance to flow through the filtered outlet perforations 6 is overcome.

Thereafter there is a continuous flow of air across the occupant's body frc7 the valves 13 to the outlets 6, acting to reduce heat stress and flush off the contaminating agent from his body/clothing. The contaminant is thence removed from the air leaving the bag by the filter pad 7, thus protecting the immediate environs of the bag from (further) contamination.

In the alternative embodiment of Figure 4, the inlets 4 and hoses 5 are dispensed with and an additional impeller unit 15 similar to the unit 10, but located outside the bag 1, is connected to an inlet 16 to provide a forced flow of air from the external environment into the bag.

If the external environment is itself contaminated suitable filters 17 will be connected to the inlets of this impeller unit. As in the previous embodiment, when the bag is closed and the unit 5 operated there will be an initial inflation of the bag until the resistance to flow through the filtered outlet perforations 6 is overcome, whereafter there is a continuous flow of air across the occupant's body from the inlet 16 to the outlets 6, acting to reduce heat stress and flush off the contaminating agent from his body/clothing, the contaminant thence being removed from the air leaving the bag by the filter pad 7 and thus protecting the immediate environs of the bag from (further) contamination. In this embodiment the air delivered to the occupant's hood 9 is derived from inside the bag and hence the provision of filters 14 associated with this impeller unit 10, selected for the agent by which the occupant is himself contaminated, is essential.

Claims

1. A respiratory protection assembly comprising: a closable bag or like enclosure adapted to accommodate the whole person to isolate the same from the external environment; a hood or other breathing interface means adapted to be worn by a person within said enclosure to isolate the wearer's breathing passages from the environment within the enclosure, and having an outlet opening into the interior of the enclosure; inlet means in the wall of the enclosure to permit the admission of air from the external environment; means to permit the passage of air out from the interior of the enclosure through filter means for removing unwanted component(s) therefrom; and means for the forced circulation of air through said inlet and of uncontaminated air through said breathing interface means.

2. An assembly according to claim 1 comprising conduit means extending from said inlet means to powered aircirculation means located within the enclosure and thence to said breathing interface means.

3. An assembly according to claim 2 comprising filter means associated with said powered air-circulation means for removing unwanted component(s) from the air passing through said conduit means.

4. An assembly according to claim 1 comprising powered air-circulation means located outside the enclosure for delivering air from the external environment through said inlet means.

5. An assembly according to claim 4 further comprising second powered air-circulation means for delivering air from the interior of the enclosure to said breathing interface means, and filter means associated therewith for removing unwanted component(s) from the air delivered to the breathing interface means.

6. A respiratory protection assembly substantially as hereinbefore described with reference to Figures 1 to 3 or Figure 4 of the accompanying drawings.