US3794030A

US3794030A - Emergency breathing apparatus

Info

Publication number: US3794030A
Application number: US00195907A
Authority: US
Inventors: H Cotabish; L Wise; E Buban
Original assignee: Mine Safety Appliances Co
Current assignee: MSA Safety Inc
Priority date: 1971-11-05
Filing date: 1971-11-05
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26

Abstract

In emergency breathing apparatus a case has a back section and a removable front cover section that are normally held together. Inside the case an airregenerating canister is secured to the back section and has a port in one end, to which a flexible breathing hose is connected. The opposite end of the canister is provided with an opening in each side, each of which is connected with an opening in one end of a breathing bag extending along that side of the canister. The hose and bags normally are folded within the case. The other ends of the bags are connected by means formed to extend around the back of the neck of a user of the apparatus to suspend the bags over his chest when they are removed from the case, with the canister between the bags.

Description

United States Patent [191 fiotabish et al.

[ Feb. 26, 1974 EMERGENCY BREATHING APPARATUS [75] Inventors: Harry N.'Cotabish, Allison Park;

' Layton A. Wise, Washington; Elmer 'E. Buban, Monroeville, all of Pa.

[73] Assignee: Mine Safety Appliances Company,

Pittsburgh, Pa.

[22] Filed: Nov. 5, 1971 [21] Appl. No.: 195,907

Related US. Application Data [62] Division of Ser. No. 12,201, Feb. 19, 1970.

[52] US. Cl. 128/202 [51] Int. Cl A6lm 15/00 [58] Field of Search 23/281, 221; 39/252 R; 128/191 R, 212, 202, 142.6, 142.2, 203; 55/518 [56] References Cited UNITED STATES PATENTS 3,390,676 7/1968 Warncke et al. 128/203 2,001,673 5/1935 Davis 128/191 R 2,390,236 12/1945 Boothby 128/191 R 603,021 4/1898 Dight 128/212 Primary Examiner-Richard A. Gaudet Assistant Examiner-Henry J. Recla Attorney, Agent, or FirmBrown, Murray, Flick &

Peckham [57] ABSTRACT In emergency breathing apparatus a case has a back section and a removable front cover section that are normally held together. Inside the case an airregenerating canister is secured to the back section and has a port in one end, to which a flexible breathing hose is connected. The opposite end of the canister is provided with an opening in each side, each of which is connected with an opening in one end of a breathing bag extending along that side of the canister. The hose and bags normally are folded within the case. The other ends of the bags are connected by 1 means formed to extend around the back of the neck of a user of the apparatus to suspend the bags over his chest when they are removed from the case, with the canister between the bags.

5 Claims, 4 Drawing Figures PATENIE r1502 6 1974 SHEET 1 BF 2 PATENTEUFEBZBW 3.794.030 SHEET 2 [IF 2 WI H Ifi

EMERGENCY BREATHING APPARATUS This application is a division of our copending application, Ser. No. 12,201, filed Feb. 19, 1970.

It is among the objects of this invention to provide emergency breathing apparatus which is neat and compact, which is hermetically sealed, which can be opened quickly and easily and set in operation without delay, and in which breathing bags support an air regenerating canister.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. I is a front view of the apparatus in operative condition;

FIG. 2 is an enlarged fragmentary front view of the apparatus, showing the canister partly in section;

FIG. 3 is a longitudinal section taken on the line III- -III of FIG. 2; and

FIG. 4 is a reduced side view of the closed case.

Referring to the drawings, a rectangular case is formed from a shallow back or base-ll and a deep cover 2. These are provided with side walls surrounded by outwardly extending flanges 3 (FIG. 3) at their free edges. Inside the case and spaced from its side walls there is a rectangular canister 4 containing a carbon dioxide absorbing and oxygen producing chemical, such as potassium superoxide. The canister is provided with end lugs 5, by which it is secured to the base, from which the canister extends well into the cover as indicated by dotted lines in FIG. 3.

As shown in FIG. I, one end of the canister, which is the upper end when it is in use, is provided with a combined inlet and outlet port 7, to which one end of a flexible breathing hose 8 is connected. The other end of the hose is provided with a mouthpiece 9 and a nose clip 10. The opposite end of the canister is provided in its side walls with openings that are connected by short tubular fittings 12 to the lower parts of a pair of breathing bags 13. The upper ends of these bags are integrally connected by a band 14 that will extend around the back of the neck of the user of this apparatus to suspend the bags over the chest. The hose and the breathing bags normally are folded into the casein the spaces between the canister and the case.

In order to seal the case so that the chemical in the canister will not deteriorate, a flexible sealing gasket 16 is disposed between the case flanges in engagement with them, as shown in FIGS. 3 and 4. The case is held closed, with the gasket clamped between the flanges, by quick release means, such as a clamping wire 17 (FIG. 4) that surrounds the gasket. The wire is bent in a more or less zig-zag fashion to form two rows of longitudinally spaced loops that extend inwardly over the case flanges and press them toward each other. The two rows of loops have to be sprung apart somewhat in order to apply them to the case, so they press the flanges toward each other and tightly against the gasket. It will be seen that in order to open the case, the clamping wire must be removed. This is done by pullingout-wardly on one end of it to strip it away from the caseflanges. For this purpose a pull tab 18 may be fastened to one end of the wire. It is obvious that the case can be opened in only a matter of seconds and the breathing bags hung around the neck, whereupon they will support the canister in upright position between them, and the canister will support theback portion of the case against the chest. Of course, the cover of the case is laid aside or discarded.

Another feature of this invention is that in spite of the use of a small case the canister inside of it is very effi cient for its small size because it is so constructed and arranged that is provides for a large cross-sectional flow area through the chemical for low breathing resistance. It also is provided with an oxygen candle to immediately generate oxygen before the potassium superoxide starts to function. As shown in FIGS. 2 and 3, the candle 25 rests on the bottom of the upright canister housing and is ignited in the usual way by a primer that is struck by a pivoted firing pin 26 (FIG. 3) moved by a spring 27 when a safety pin 28 is pulled. Immediately above the candle there is a partition or shelf 29 that ex tends from side to side of the canister and that is attached to its front wall as well as its sides to divide the canister into a tall upper chamber and a short lower chamber. The canister is provided at the back with a passage 30 past the partition to connect the two chambers. This may be done by openings in the partition, or by spacing it from the back of the canister housing, in which case the rear edge of the shelf is turned up to form a flange 31.

Fittings 12 for the breathing bags are at the opposite sides of the lower chamber containing the candle. Port 7 is in the front of the top wall of the canister.

Resting on the front of shelf 29 is the lower end of an inclined perforated metal plate 32, the upper end of which is directly behind the port 7. This plate is spaced from the front of the canister housing by integral downwardly tapered side flanges 33 that engage the front wall. Immediately behind the plate there is a thin mat 34 of filtering material and then a screen 35. Behind the screen there is the bed of potassium superoxide 36 and then another screen 37, another filter mat 38, and another perofrated metal plate 39 resting on the back of the shelf. This plate is held in inclined position, spaced from the back of the canister, by means of a spring 40 compressed between it and the back wall. It also is desirable to provide molecular sieves 4E between the chemical bed and the screens. The sieves absorb moisture to reduce or prevent over production of oxygen and thereby extend the life of the chemical bed. Also, if the chemical absorbs too much moisture it may soften and run and tend to clog the filters, which would increase the breathing resistance. The molecular sieves help to prevent this from happening.

Air exhaled into the canister through the hose can flow down to shelf 29 and thus enter the chemical bed through the large area of plate 32. The air, with carbon dioxide removed from it and enriched with oxygen, leaves the chemical through the entire area of plate 39 and then flows downwardly behind the shelf and into the breathing bags. With such a large area of the chemical exposed to the air, breathing resistance is held to a minimum during both exhalation and the return inhalation, even though the canister must be kept small to fit in the case.

Since considerable heat is generated in the canister by the chemical reaction, it is desirable to provide means for cooling the air being inhaled. This can be done by trapping moisture from the exhaled breath and then returning that moisture to the inhaled air to cool it. The returned moisture also humidifies the dry air. Suitable means for accomplishing this purpose is a roll of metal screen 43 placed in a section of the breathing hose, as shown in FIG. 1, where it is held in place by frictional engagement with the hose. Exhaled air passing through the screen roll deposits moisture on it, but during inhalation this moisture is picked up by the incoming dry air which is thereby humidified and cooled due to evaporation of the trapped moisture.

This small, self-contained breathing apparatus remains sealed and operative until the case is opened. It is quickly hung in place without the use of straps or other fasteners. The canister occupies the space between the breathing bags and projects only a short distance forward from the chest. Yet, due to its construction and the way in which it is suspended, it has considerable capacity and effectiveness.

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.

We claim:

1. Emergency breathing apparatus comprising a vertically elongated case having a back section and a removable front cover section, means normally holding said sections together to keep the case closed, an air purifying and oxygen producing rectangular canister inside the case and secured to its back section, the canister having an inlet-outlet port in its upper end, a flexible breathing hose connected to said port, the lower end portion of the canister being provided with an opening in each side, a breathing bag extending along each side of the canister and provided at its lower end with an inlet-outlet opening, attaching means connecting each bag opening with the adjacent one of said canister openings and thereby attaching the bags to the canister to support it, the hose and bags normally being folded within the case, and means connecting the upper ends of said bags and formed to extend around the back of the neck of a user of the apparatus to suspend the bags over his chest when they are removed from the case, whereby the bags and said attaching means will support the canister upright between the bags and it will support said back section of the opened case upright against the chest.

2. Emergency breathing apparatus according to claim 1, in which said canister includes a housing having front and back walls connected by side walls and end walls, a transverse partition in the housing extending from side to side thereof adjacent said canister openings but between them and said port, the partition extending rearwardly from said front wall to form a short chamber between said openings that is defined by said front and back and side walls and the nearest end wall, a long chamber being formed by the rest of the housing between the partition and said port, the canister housing being provided at the back with a passage past said partition for connecting said chambers, an air purifying and oxygen producing chemical bed in said long chamber between said passage and port, an oxygen candle in said short chamber, and manually operable means outside of said housing for igniting the candle when the case is open.

3. Emergency breathing apparatus according to claim 2, including molecular sieves between said chemical bed and said port and passage.

4. Emergency breathing apparatus according to claim 2, in which said inlet and outlet port is adjacent the front wall of the housing, a perforated plate in said long chamber engages said partition and is inclined backwardly therefrom to a point behind said port, the plate having means spacing it from the front wall, a filter mat engages the back of the plate, a first screen engages the back of the mat, a second screen is spaced behind the first screen with said chemical bed between them, a filter mat is behind the second screen, an inclined perforated plate engages said partition behind the second mat, and a spring between the back plate and the back wall of the housing presses the back plate forward.

5. Emergency breathing apparatus according to claim 4, including molecular sieves between said chemical bed and screens.