GB2169810A - Simulator - Google Patents

Abstract

A simulator for a filter self rescuer has a mouthpiece (1) connected to a canister (9) open to the atmosphere (apertures, 10) providing a breathing path through the canister both on exhalation and inhalation. A flap valve (7) with a restricted opening operates to give a relatively high breathing resistance upon inhalation, and a relatively low breathing resistance upon exhalation. The simulator provides realistic training. <IMAGE>

Description

SPECIFICAtlON Simulator This invention concerns a simulator, more especially it concerns a filter self rescuer simulator.

Filter self rescuers are well known in coal mining, and are a small breathing apparatus which converts poisonous carbon monoxide into carbon dioxide by catalytic oxidation, and enable a wearer to escape to a safer environment.

We have described, in UK Patent No. 2011 792B, the first successful self rescuer simulator which simulates the rise in temperature in a real self rescuer as a wearer breathes in an atmosphere contaminated with carbon monoxide.

We now believe that it is important, in training personnel to use self rescuers correctly and safely, that a wearer should experience the same or similar breathing characteristics in a simulator as in a real self rescuer.

In the real self rescuer, inhalations pass through a bed of catalyst before passing through a heat exchanger to the mouthpiece, and the exhalations pass through the heat exchanger and pass out of the apparatus through an exhalation valve. Accordingly, the wearer experiences a greater breathing resistance on inhalation, as the inhaled air has to pass through the bed of catalyst, compared to exhalation. Breathing resistances on inhalation and exhalation are typically 10 mbar and 3.5 mbar, respectively.

The present invention now provides a self rescuer simulator, comprising a mouthpiece connected to a canister having an opening to the atmosphere and arranged to provide a breathing path through said canister on inhalation and exhalation, and a valve which operates upon inhalation to provide a relatively high breathing resistance and upon exhalation to provide a relatively low breathing resistance.

The invention in one embodiment is a "cold" simulator, in which the wearer experi- ences only the difference in breathing resistance while at the same time becoming accustomed to the shape and feel of a self rescuer in the mouth.

Preferably, however, the invention is used together with the invention of the "hot" training apparatus of UKP 2011792, in order to provide to personnel a relatively authentic experience.

Preferably, the canister is detachable from the mouthpiece, so that replacement canisters containing heat-generating chemicais may be used with the same mouthpiece. The mouthpiece is preferably moulded in plastics and rubber as a mouthpiece housing and preferably models the mouthpiece housing of a genuine self rescuer. The mouthpiece is preferably adapted to be easily rinsed and disinfected after use, to permit financial savings by multiple use.

Preferably, the mouthpiece comprises a breathing tube within a housing, and the valve is fitted in, or on the end of, the breathing tube.

A suitable valve has been found to be a flap valve having a restricted opening therein. Such a valve may operate by moving freely off a seating upon exhalation, providing relatively low resistance to exhalation. By locating on the seating upon inhalation, inhaled air has to pass through the restricted opening, providing a relatively high resistance to inhalation. The restricted opening may be a single opening or a number of smaller openings or a mesh, fabric etc. Such a valve may be made of plastics, metal or a material such as mica.

Other single or multiple valves may be used to perform the same function, and the particular valve chosen is not critical.

The invention will now be described with reference to the accompanying drawings, in which Figure 1 is a cross-section of a simulator according to the invention, with the valve in a first position during inhalation, and Figure 2 is a cross-section of the simulator of Fig. 1, showing the valve in a second position during exhalation.

Referring to the drawings, the simulator has a mouthpiece, 1, connecting with a breathing tube, 2, located within a mouthpiece housing, 3. The mouthpiece housing, breathing tube and mouthpiece are moulded integrally in a synthetic rubber, and the housing has a chin rest, 4, and an authentic but non-operational exhalation valve,5.

The end of the breathing tube 2 forms a valve seating, 6, for a disc-shaped flap valve, 7, made from 0.127 mm mica sheet. The valve has the same diameter (24 mm) as the end of the breathing tube, and has a central aperture of 7 mm diameter. The valve is affixed to the mouthpiece housing by a strip of adhesive aluminium foil, 8.

The mouthpiece housing is releasably attached to a metal canister, 9, containing a charge of soda lime and drying agents, for example as described in UKP 2011792B, for example by a bayonet fitting (not shown). The canister is open to ambient air by means of multiple apertures, 10, in its base.

In use, an inhalation causes the flap valve to seat on the end of the breathing tube 2, as shown in Fig. 1, and initial experiments using a canister filled with a training charge show a breathing resistance of about 10 mbar. Upon the user exhaling, the flap valve opens to the position shown in Fig. 2, and a significantly lower breathing resistance of 3.4 mbar was found. These resistances are typical of and within the acceptable specification of a commercial self rescuer. The initial subjective tests indicate that the simulator of the invention, in its preferred form with "hot air" simulator, is capable of authentic simulation of the use of a real self rescuer in a hazardous environment containing carbon monoxide, and is therefore a useful training aid.

Claims (5)

1. A self rescuer simulator comprising a mouthpiece connected to a canister having an opening to the atmosphere and arranged to provide a breathing path through said canister on inhalation and exhalation, and a valve which operates upon inhalation to provide a relatively high breathing resistance and upon exhalation to provide a relatively low breathing resistance.

2. A simulator according to claim 1, wherein the canister contains a reagent which reacts with the carbon dioxide and/or moisture in exhalations to produce heat which is effective to heat inhaiations as they pass through the canister.

3. A simulator according to claim 1 or 2, wherein the mouthpiece comprises a breathing tube within a housing, and the valve is fitted in, or on the end of, the breathing tube.

4. A simulator according to claim 1, 2 or 3, wherein the valve is a flap valve having a restricted opening therein.

5. A simulator according to claim 1, sub stantiaily as hereinbefore described with reference to the accompanying drawings.