US3403981A - Oxygen producing canister - Google Patents

Description

Oct. 1, 1968 w. K. LEMCKE ETAL 3,403,981

OXYGEN PRODUCING CANISTER Filed Sept. 15, 1965 INVENTORS. WATER K. LEMCKE HANS E. REECK K their 2 arr-02)? United States Patent 3,403,981 OXYGEN PRODUCING CANISTER Walter K. Lemcke and Hans E. Reeck, Berlin, Germany,

assignors to Auergesellschaft G.m.b.H., Berlin, Germany, a corporation of Germany Filed Sept. 15, 1965, Ser. No. 487,476 Claims priority, application 1Gig-many, Sept. 22, 1964,

3 Claims. ci. 23-281) ABSTRACT OF THE DISCLOSURE This invention relates to breathing apparatus canisters, and more particularly to those containing a chemical that absorbs carbon dioxide and generates oxygen when contacted with the exhaled breath of the user.

It is well known to use in self-contained, or closed cycle breathing apparatus a canister containing a chemical such as, for example, K0 that evolves oxygen through the action of carbon dioxide and water contained in exhaled breath. It is important that such canisters not only release oxygen in sufficient amounts for breathing, but also capture substantially all the exhaled carbon dioxide in order to avoid undesirable stimulation of the breathing process by reinhalation of carbon dioxide. Although carbon dioxide is most effectively removed by thin layering of the chemical in the canister, such packing leads to severe caking of the chemical during use that results in a considerable increase in resistance to flow through the canister which makes breathing significantly more difiicult. Heretofore, breathing resistance has been decreased by placing the chemical on corrugated screens in a parallel or crisscross arrangement, but carbon dioxide is passed by such canisters in relatively large amounts.

It is among the objects of this invention to provide a canister of the oxygen-producing type that substantially completely absorbs the carbon dioxide from exhaled air and that has a low breathing resistance over the entire life of the canister.

In accordance with this invention, a breathing apparatus canister housing has inlet and outlet openings, and contains layers of granular chemical that will absorb carbon dioxide and generate oxygen when contacted with exhaled breath disposed transversely to the direction of air flow through the canister. A plurality of the layers are discontinuous, having passages or air channels extending therethrough, and are conveniently formed by supporting the granular chemical on a screen having grooves equal in depth to the layer thickness. The discontinuous layers are spaced from each other by a continuous layer of granular chemical confined between screens. It is preferred that the layer adjacent the canister inlet opening be a continuous layer.

A preferred embodiment of the invention is illustrated in the accompanying drawing, in which the single figure is a side view of our breathing apparatus canister with about half of it shown in section.

Referring to the drawing, a conventional metal canister 1, generally cylindrical or oval-shaped, is provided in 3,403,981 Patented Oct. 1, 1968 "ice its opposite ends with inlet and outlet openings 2 and 3 that are preferably at the center of the housing. These openings are surrounded by tubular extensions 4 that can be connected to hoses that conduct exhaled air away from the user and deliver purified air and oxygen to him. The canister is also suitable for use in apparatus in which both exhaled air and inhaled air pass through the canister; in such apparatus the inlet opening 2 is connected to a hose leading to a breathing mask and Outlet opening 3 is connected to a breathing bag. The canister as shown has six layers, although three may be sufiicient in some cases, while in other cases it may be desirable to have more than six layers.

The discontinuous layers 5 are formed of granular chemical, such as K0 supported on screens 6 having grooves 7 extending the full depth of the layer so that the unfilled grooves provide an air distribution channel through the layer. The sidewalls of the grooves may have protuberances, or dimples, 8 that strengthen the screen and provide for a constant width of the grooves. The chemical tends to swell on reaction with exhaled breath, so if necessary, depending on the strength of the screen used, the grooves may be reinforced by spacers, suitably corrugated screen inserted into the grooves.

The discontinuous layers are spaced from each other by continuous layers 9 of the same granular chemical extending fully across the canister and confined between a flat lower screen 10 and a flat upper screen 11. The screens confining the continuous layer may be formed by attaching the upper parts of the grooved screen together and covering the lower open parts of the groove with pieces of screen. In the preferred construction, screens 11 and 6 provide a small air distribution space between the upper surface of the continuous layer and the lower surface of the discontinuous layer. If desired, screens 11 and 6 may be separated by spacers to provide a larger air distribution channel. Preferably, the granules of the continuous layer are larger than the granules of the discontinuous layer.

It is preferred that the continuous layer adjacent the inlet opening for exhaled breath be a continuous layer and be spaced from the end of the canister a short distance by a screen 12.

With the canister of this invention, a substantially complete absorption of carbon dioxide is obtained throughout the time of use, while at the same time, a low breathing resistance is maintained. The continuous layers prevent any substantial short circuiting of the exhaled breath around the granular chemical, while heat occurring during the reaction, the primary cause of caking and high breathing resistance, is dissipated or conducted off by the screen layers and air spaces in the discontinuous layer.

According to the provisions of the patent statutes, we have explained the principle and mode of practice of our invention and have 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 described.

We claim:

1. An oxygen producing canister having opposed inlet and outlet openings and containing a granular chemical that absorbs carbon dioxide and generates oxygen on contact with exhaled breath, a plurality of first and second layers transverse to said openings and alternately disposed lengthwise of said openings; said first layers each consisting of a first flat screen, a second flat screen and a first bed of said granular chemical confined therebetween, said second screen being remote from said inlet opening; said second layers each consisting of a third References Cited screen having grooves therein and a second bed of said granular chemical of a depth equal to the depth of said UNITED STATES PATENTS grooves, said second bed being confined between said sec- 2 4 9 3 7 5 1949 Burggss et 1 3 0nd and third screens; and the granules of said first bed 5 2 913,317 11 1959 Bovard 3 1 being of a larger size than the granules of said second bed.

2. A canister according to claim 1 having separator REIGN PATENTS means spacing said first and third screens. 7 52 323 9/ 1 France 3. A canister according to claim 1 having means reinforcing said grooves against collapse. 10 JAMES H. TAYMAN, JR., Primary Examiner.

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