Closed circuit breathing apparatus

Sept. 16, 1958 w. c. Hamilton etal 2,852,023

CLOSED CIRCUIT BREATHING APPARATUS Filed Nov. 6, 1956 2 Sheets-Sheet 1

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Sept. 16, 1958

Filed Nov. 6, 1956

W. C. HAMILTON ETAL

CLOSED CIRCUIT BREATHING APPARATUS

2,852,023

Sheets-Sheet 2

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United States Patent Office

2,852,023

Patented Sept. 16, 1958

2,852,023

CLOSED CIRCUIT BREATHING APPARATUS

William C. Hamilton and Robert M. Bovard, Pittsburgh, . Pa., assignors to Mine Safety Appliances Company,

Pittsburgh, Pa., a corporation of Pennsylvania

Application November 6,1956, Serial No. 620,686

Claims. (Cl. 128—203)

This invention relaties to breathing apparatus, and more particularly to closed circuit apparatus provided with an auxiliary oxygen supply.

It is among the objects of this invention to provide closed circuit breathing apparatus which is small and compact, which operates at low pressure, which is particularly adapted to emergency use, which is inexpensive, which uses no valves or regulators, which employs both a self-generating canister and an auxiliary oxygen supply, which can be started in operation instantaneously or more slowly, which is unaffected by ambient temperatures, and which may remain in fully assembled condition until ready for use.

In accordance with this invention the breathing apparatus has a conduit for both inhalation and exhalation. Connected to the end of the conduit opposite the end applied to the face is an inlet and outlet opening of a breathing bag, which receives air exhaled through the conduit and from which such air is inaled. Disposed in the conduit in the path of the air is an air-purifying canister filled with material which removes carbon dioxide and generates oxygen. Associated with the conduit is a receiver for a small high pressure oxygen cartridge. The receiver is connected with the inside of the conduit through a tubular fitting. The cartridge in the receiver can be opened by manually operable means to allow oxygen therefrom to enter the conduit. When the apparatus is not in use, the breathing bag is held in a small compact bundle by means which can be released whenever desired and automatically when the oxygen cartridge is opened.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a side view of the breathing apparatus;

Fig. 2 is a fragmentary vertical section taken on the line II—II of Fig. 1; and

Fig. 3 is a fragmentary front view of the apparatus, partly in section, after the oxygen cartridge has been opened and the breathing bag has been released.

Referring to Figs. 1 and 2 of the drawings, a flexible breathing tube 1 is provided at its upper end with means for connection to the face of the user. This may be a mask, but preferably is simply a flange 2 which fits behind the lips in a well-known manner. Dirt and moisture are prevented from entering the upper end of the tube when not in use by a suitable stopper 3. A lanyard 4 may be connected to the tube or some other part of the apparatus for supporting a conventional nose clamp 5.

The lower end of the breathing tube is clamped on a tubular flange 7 projecting up around a central opening 8 in the cover 9 of a housing 10 for an air-purifying canister 11. The canister contains a well-known chemical 12 which will remove carbon dioxide from the exhaled breath of the user and generate oxygen to be inhaled by him. The canister has flanged openings 13 in its opposite ends encircled by sealing gaskets 14 which are pressed against the top and bottom of the housing when cover 9 is attached to the rest of the housing, such as by bayonet joints 15. The bottom of the housing is provided with a central opening 16, from which a short rigid coupling tube 17 extends downward. Secured to the lower end of this tube is the neck 18 of a flexible breathing bag ⁵ 19. This neck forms a combined inlet and outlet opening for the bag. The breathing tube 1, canister housing 10 and coupling tube 17 form a conduit, through which air flows back and forth between the mouth of the user and the breathing bag.

The side wall of coupling tube 17 is provided with a small opening 21, and a tubular fitting 22 has one end welded to the side of the tube. This fitting extends radially away from the tube and has a passage 23 through it communicating with the opening in the side of the adI⁵ joining tube. The upper part of the fitting is provided with a vertical opening 24 and supports a vertical receiver 26 for a high pressure oxygen cartridge 27 of the “Sparklet” type. The lower end of the receiver is tightly secured to the tubular fitting and is provided with a vertical opening 28 in line with opening 24. The receiver includes a knurled ring 29 that is screwed onto its upper end for engaging the top of the cartridge and pressing its reduced lower end down onto a sealing gasket 30 _ encircling the opening in the lower end of the receiver. ^2o The radial opening 24 in the tubular fitting opens into the top of an enlarged portion of passage 23 therein and contains a cartridge perforator 31 having a pointed upper end. The enlarged lower end of the perforator fits loosely within opening 24, so that there will be sufficient clear³⁰ ance for the passage of oxygen through that opening, and rests on the central portion of a plunger rod 32. The outer end of the plunger is slidably mounted in the outer end of the tubular fitting, where it is encircled by a _or. packing gasket 33. . A coil spring 34 encircles the plunger and urges it toward the coupling tube. The plunger projects from the tubular fitting and can be pulled out a certain distance by a pull ring 35. When the rod is pulled out in this manner, the inclined side of an integral collar 36 encircling the rod forms a cam surface which pushes ⁴¹¹ the perforator upward to cause it to penetrate the lower end of the oxygen cartridge. The high pressure oxygen in the cartridge then will escape down through the bottom of the receiver and into the tubular fitting and from there into the coupling tube.

⁴³ Another feature of this invention is that the apparatus is rendered more compact when not in use by compressing the breathing bag into a small bundle. This is preferably done by folding the opposite side edges of the bag toward each other and then rolling the bag up into a ^S compact roll. It is held rolled up by a cord 37 attached at one end to the bottom of the housing and removably supported at its opposite end by an L-shaped bracket 38 connected with the projecting end of the plunger rod in _r _ the tubular fitting. More specifically, this opposite end ⁰⁰ of the cord is preferably provided with an enlargement, such as a bead 39, which is held up in a recess 41 in the bottom of the tubular fitting by the part of the bracket that extends along the bottom of the fitting. This lower end of the bracket is provided with an open-end slot 42, in which the cord bead is supported. When ring 35 is pulled to cause the cartridge to be punctured, the bracket is pulled away from the bead to release the cord from the tubular fitting so that the bag will unroll. Since there are cases, as will be explained presently, where it may ⁶⁵ be desirable not to use oxygen from the cartridge, the housing end of the cord may be secured to a flexible tab 43 normally held in place by a button 44 fastened to the housing. This tab can be pulled down to remove the 70 ^{cord 4rom} th^e button in order to release the bag while the bead end of the cord remains attached to the tubular fitting.

The&gt;. breathing apparatus described herein can be used

2,852,023 in three different ways. If the air suddenly becomes contaminated, a person carrying the apparatus can hold his breath long enough to insert the breathing tube in his mouth, apply the nose clamp and pull ring 35 to puncture the oxygen cartridge and simultaneously release the breathing bag. The compressed oxygen will immediately fill the bag, so the user can start breathing at once. By the time the oxygen is consumed, the chemical in the canister will be generating oxygen. This manner of starting the apparatus can also be used when the ambient temperature is so low that initiation of the chemical reaction in the canister would be retarded too long. On the other hand, if there is not so much hurry about using the apparatus, the user will not need to use ths oxygen cartridge but can pull tab 43 to release the breathing bag and then wait until the moisture in his breath has started the canister chemical producing oxygen. He will then have the cartridge oxygen in reserve for the third case, which occurs when the chemical is exhausted before escape can be made from the vitiated atmosphere. In such a case he can open the cartridge to release oxygen that he can breath for a while longer.

Although this apparatus is intended primarily for emergency escapes and self-rescues, it also can be employed as an inexpensive training apparatus for use of self-contained breathing apparatus, without the expense of costly long-service canisters. The apparatus may also be used for inspection or rescue work where the user requires only a few minutes working time and where he has ready access to a respirable atmosphere, such as would be the case when working in tanks, manholes or holds. The size of the canister is such that it is good for about five minutes when the user is working or moving about. When he is not working or moving around, the canister will provide oxygen sufficient for fifteen or twenty minutes use. The apparatus is compact and light weight and therefore convenient to carry. The basic assembly is permanent and reusable and utilizes-an inexpensive, expendable replacement canister and cartridge. The appaartus is not subject to freezing, and variations in ambient temperatures have no effect on it.

According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.