Respirator

June 29, 1937.

2,085,249

E. W. BULLARD

RESPIRATOR

Filed Oct. 2, 1933

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H/S ATTORNEY

Patented June 29, 1937

2,085,249

UNITED STATES PATENT OFFICE

2,085,249

RESPIRATOR.

Edward W. Bullard, San Francisco, Calif., assignor, by mesne assignments, to E. D. Bullard Company, San Francisco, Calif., a corporation of California

Application October 2, 1933, Serial No. 691,833

Claims.

My invention relates to a respirator, and more particularly to apparatus for supplying or conditioning air for a gas mask.

It is among the objects of my invention to· pro5 vide apparatus in which a primary unit supplies fresh air from a remote source, and in which a secondary unit for purifying the local air automatically becomes operative in the event the primary supply of fresh air is cut off.

Another object of my invention is to provide an auxiliary unit for operation in conjunction with the secondary or canister unit and by which oxygen may be fed into the air supplied through the canister.

A further object of my invention is to provide an assembly of the apparatus by which it may conveniently be carried on the person of the wearer.

The invention possesses other objects and fea20 tures of advantage, some of which, with the foregoing, will be set forth in the following description of my invention. It is to be understood that I do not limit myself to this disclosure of species of my invention, as I may adopt variant embodies ments thereof within the scope of the claims

Referring to the drawing:

The figure in the drawing is an elevational view showing the respirator of my invention, portions of the apparatus being shown in vertical 30 section to illustrate the construction more clearly.

In terms of broad inclusion, the respirator embodying my invention comprises a breathing chamber from which air is drawn into a mask. A primary unit is provided in the apparatus for 35 normally supplying fresh air under pressure to the chamber from a remote source. A normally , inoperative secondary unit is also· provided for purifying the local contaminated air and supplying the same to the chamber, and means are .40 provided for rendering the secondary unit operative when the primary supply of air is cut off. An auxiliary unit operable alone or in conjunction with the secondary unit is also· preferably provided for introducing oxygen into the cham. 45 ber.

In greater detail, and with reference to the figure in the drawing, the respirator embodying my invention comprises a frame 2 on the upper end of which a breathing chamber 3 is mounted. 50 A flexible duct 4 is connected to the breathing chamber 3, through which air may be drawn into a suitable mask on the face of the wearer and any ordinary gas mask having the usual exhaling valve may be used. The apparatus is sup55 ported on the body of the wearer by a harness (CI. 128—145) preferably comprising a waist encircling strap 5 and a pair of shoulder straps 7.

The shoulder straps are permanently fastened at their lower ends to the waist band 6, and are detachably connected at their upper ends to the 5 chamber 3 by suitable buckles 8. The lower end of the frame 2 is connected to the waist band 6 by depending straps 9. Suitable buckles 11 are also provided in the straps 6 and 7 for adjustment of the harness. By this arrangement of the 10 harness the apparatus may be worn on either the front or the back of the wearer.

A primary unit is provided in the apparatus of my invention for normally supplying fresh air under pressure to the breathing chamber 3 from 15 a remote source, such as an air compressor. In fire apparatus the compressor on the truck may conveniently be employed. Since the pressure from such a source is usually around 100 pounds per square inch, I provide a valve for reducing ₂o this pressure to a predetermined value suitable for breathing purposes, say 2½ pounds per square inch (gage pressure). The reducing valve is preferably constructed as a part of the chamber 3 and the volume of air supplied through the ₂5 valve is preferably such as to maintain the pressure in the chamber at the predetermined value at all times.

This valve may be of any suitable construction. For purposes of illustration I have shown 30 one comprising a spring loaded diaphragm 12 having connected thereto an outwardly extending yoke-shaped arm terminating in a valve head (3 seated over a restricted orifice 14. The yoke shape of the supporting arm which mounts 35 the valve head 13 for movement with the diaphragm ί 2 permits this arm to clear the internal part of the chamber casting. The diaphragm ! 2 is responsive to pressures in the chamber 3, and the loading of the diaphragm spring 15 is such 40 that when the pressure in the chamber drops below the 2½ pounds pressure the diaphragm will move to open the valve and allow more air to enter the chamber.

The compressed air is fed to the orifice 14 45 through a passage 16 from a feeder duct 17. The passage 16 is divided into two sections connected through a spring pressed check valve i8. The duct 17. is flexible and its lower end is anchored in a lug 19 bolted to the waist strap 6 of the 50 harness. At this point the duct 17 connects with a hose 21 which communicates with the source of air pressure.

The hose 21 may be of any length, depending upon the distance which the operator has to 55

2,085,249 travel from the source of pressure. An important point in the construction to be noted is the anchoring of the hose 21 to the waist band S of the harness. This permits the hose to be 5 dragged around by the operator without requiring the use of his hands, and without subjecting the apparatus to undue stress.

A normally inoperative secondary unit is provided for purifying the local contaminated air 10 and supplying the same to the breathing chamber 3 in the event the primary supply of air is cut off. Occasionally an operator, such as a fireman, becomes trapped in a position where he must cut his air hose in order to escape. At other 15 times the supply of fresh air may be cut off by an accidental burning or cutting of the hose.

The secondary unit preferably comprises a canister 22 mounted on the frame 2 and connected to the breathing chamber 3. A hinged clip 20 23 is preferably provided for demountably fastening the canister. This canister provides a passage communicating with the atmosphere and opening into the breathing chamber. The element or agent 24 in the canister by which the 25 poisonous air is rendered harmless may be of any suitable composition.

ί The passage of air through the canister is controlled by a suitable spring pressed check valve 25, preferably seated on the apertured bottom of the 30 canister so that the lower side of the valve is exposed to atmospheric pressure. This check valve is arranged so that it is closable by pressure with• in the breathing chamber, so that the valve stays closed as long as the pressure in the chamber is 35 above atmospheric pressure, but opens as soon as the pressure in the chamber drops below atmos, pheric pressure. As long as the pressure conditions in the chamber 3 are merely affected by the inhaling of the operator the valve 25 will open 40 and close in time with the breathing, but while the fresh air is being supplied to the chamber, and the pressure maintained above atmospheric pressure, the valve 25 will be held closed.

The valve 25 therefore automatically operates 45 to throw the secondary or canister unit into operation when the primary supply of air fails. Of course when the air pressure is cut off the check valve 18 closes to seal the chamber against the entrance of gas through the duct 17.

An auxiliary unit is also preferably provided for supplying oxygen to the breathing chamber In the event sufficient oxygen is not supplied through the canister. This unit comprises a container or tank 26 for holding a supply of oxygen 55 under pressure, preferably at about 2000 pounds per square inch. This tank is removably held on the frame 2 by a suitable clip 27, and is preferably positioned with its neck or valve end down. The tank is connected to the chamber by a suit60 able duct 28. Communication between the tank and chamber is controlled by a hand valve 29. The positioning of this valve adjacent the lower portion of the apparatus permits an operator to readily reach it when the apparatus is being car65 ried on his back.

A reducing valve 30 is also provided in the line of communication beween the tank and chamber for reducing the pressure to some predetermined value suitable for breathing purposes, say 70 2½ pounds per square inch. The passage for the oxygen leading into the chamber 3 however is comparatively small, so that only small quantities of the oxygen are fed into the chamber. In this respect the introduction of the oxygen differs 75 from the introduction of the fresh air. The lat ter was introduced in quantities sufficient to maintain the pressure in the chamber above atmospheric pressure, thereby holding the canister valve 25 closed. In the case of the oxygen however the pressure in the chamber is not material- 5 ly affected, and the valve 25 opens and closes with the breathing of the operator in the usual manner.

With a small duct or passage between the oxygen bottle and breathing chamber the reducing io valve 30 may be unnecessary as the hand valve 29 may be opened but slightly thereby allowing a small trickle of the gas to pass. It is also to be understood that the oxygen can be used alone in the breathing chamber for 7 or 8 minutes. With 15 a proper control of the gas pressure in the breathing chamber the canister valve 25 can be made either operative or inoperative, so that the oxygen may be supplied either pure or in conjunction with air drawn through the canister. 20

For the convenience of an operator I also preferably provide an electric lamp 32 mounted on an arm 33 terminating in a ball and socket joint 34 at one end of the chamber 3. Current for the lamp is preferably provided by batteries held in a 25 tubular casing 36 formed as an integral part of the frame 2.