US1537519A - Indicating gas-mask canister - Google Patents

Description

May 12, 1925.

M. YABLlCK INDIGATING GAS MASK CANISTER Filed Dec. 5, 1924 NIH INVENTQR MarJ'Zzfi/zb/r BY I My ATTORNEYS Patented May 12, 1925.

UNITED STATES PATENT OFFICE.

MAX YABLICK, OF NEW YORK, N. Y.

INDICATING GAS-MASK CANISTER.

Application filed lpecember 5 1924. Serial No. (54,108.

To all whom it may concern: 7

Be it known that I, MAX YABLIGK, a citizen of the United States, and resident' of New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Indicating Gas-Mask Canisters, of which the following is a specification.

My present invention relates primarily to respirators and more particularly to the canisters thereof for intercepting or separating out poisonous or obnoxious gases from air, drawn therethrough in the process of inhalation.

Since an ordinary canister comprising a metal cas ng enclosing the gas absorbing or intercepting composition through which the air is drawn, does not indicate the extent of residual life after use, such canister when reused, may fail at such time as it is most needed, while discarding of a canister after but a single use usually involves waste.

It is accordingly, among the objects of the invention to provide a canister which will indicate while in or out of use, without the need for separate testing appliances or operations, the proportion of residual life therein.

Another object is to provide indicating means for the purpose mentioned which shall not necessitate any substantial change in the construction or design of canisters in commonuse, which shall in no way interfere with the efficacy of the-canister in the regular performance of its function, nor involve added d scomfort or danger in use,

which shall operate reliably without possibility of a false registration, which shall involve no delicate mechanical or other appliances likely to;become out of order, and.

which shall not add' appreciably to the cost of the canister.

My present invention has a preferred field of application to canisters, the fillers of which preferably of granular material, have a'marked avidity for the impurity to be intercepted, absorbed, adsorbed or occluded.

the first illustration.

after it has intercepted the gaseous impurity, the indication can be effected through a window in the canister extending the height thereof or by providing a transparent can'- ister wall. On the other hand, where the gas does not change the color or'appearance of the filler, the latter may be impregnated with an appropriate indicator for the gas, so that the indication can be effected as in Where it is not desiredto use an indicating impregnation, an indicator test strip may be used, extending the height of the canister in contact with the filler, and preferably superposed over the inner wall of the canister,- and exposed through a transparent or open wall portion, or the container wall itself or a partthere-v of may be of an absorbent material impregnated with the indicator, and exteriorly covered with a transparent gas resisting coatin", such as shellac.

In the present application, I claim generically the various alternative embodiments and applications herein disclosed and specifically the application to a respirator for abstract ng ammonia and utilizing a filler which inherently changes color when combined with the ammonia. All novel'subjectmatter including the application of a separate indicator and also the detailed me- 'chanical construction of thecanister and more especially of the window are claimed in mv copendino' d visional application, Serial No. 18,161 filed March 25th 1925.

In the accompanying drawings in which is shown one or more of various possible embodiments of the several features of this invention;

Fig. 1 is a side view of a preferred canister,

Fig. 2 is a view in longitudinal section taken along the line 22 of Fig. 1, and;

Fig. 3 is a fragmentary longitudinal sectional view of a modification.

The casing of the canister is substantially conventional, including the usual shape The filler 15, preferably a granular substance, may be supported upon a layer 116 of absorbent cotton, in turn, upon a curved. wire mesh seat 17 above the flap valve 11,. affording a space 18 in which" the flap valve comprismg a narrow strip of transparent dering asat 2'5.

material such as glass held in place in the canlster 1n any of a wide varlety of manners.

By way'of lllliSllIfitlQIl, I have shown the windon lodged in an integral rectangular.

frame .24, pressed outward from the metal of the canister and fixed in position by sol- Ifreferably the window is a thick pane of triplex or iion-shatterable glass comprising twothinner panes of glass cemented to an interposed sheet 23 of celluloid or the like. The inner wall of pane 25 may be provided'with a series of prisms 26 extending horizontally thereacross in contact with the absorbent filler for a purpose which will appear fully in the operation set forth below.

The filler it will be understood is of composition and physical. construction such as to have a particular affinity or avidity for the gas or gases to be abstracted from. the air drawnthrough'the canister into the lungs of the user. In certain applications, the canister contents will change color or appearance when the gas has been absorbed.

thereby, for instance, in the use of a filler of copper sulphate crystals, impregnating granules of pumice stone or the like, the natural green color changes to blue when ammonia has replaced the water of crystallization in whole or in part.

As the ammonia laden air is drawn-into the canister, the ammonia/will rapidly be absorbed by the bottom layer of the filler and air freed from ammonia is drawn pregnate the absorbent with an indicator,- a

through the rest of the filler; so that the ammonia saturated compound at the bottom of the-canister, will appear blue after use, while the rest of the filler above said bottom will remain green. By inspection through the window, therefore, .it is instantly ascertained what proportion of the lifeof the canister--has been spent and to what extent therefore, the canister is available for further use.

The presence of the multiplicity of transverse ribs on the window againstwhich the granular contents in the canister is firmly pressed, obstructs any possible relatively free path for the air along theminute gap, whlch might otherwise exist between the window and the contents, and thereby avoids the possibility of the impurity in the air when drawn through the canister, rapidly-changing the c0101 of the entire length of filler exposed through the window, and giving a false indication where the body' of the filler is not spent. By the rib construction, it is seen that the air is not readily drawn throughthe path of greatly increased resist- -In some cases, however, the filler will not change in color or physical appearance after it has absorbed the impurity on which it is toact, sufiiciently to afford a line. of demarcation between the saturated and the freshpart. In such case, it is desirable to combine with the filler an appropriate indi- 'cator which will change color by the action of the impurity, the indicator, of course, in

each case being such as not to impair the efiicacy of normal operation. For instance, the usual filler of soda lime employed as an absorbent for hydrogen sulphide does not appreciably change color after it has been saturated by the gas, so that the residual life ofthe canister could not readily be ascertained by inspection through the window. In this case, I preferably spray the soda lime with a solution of lead salt. such as lead acetate. The lead salt, as will be understood, is converted into the black lead sulphide, when acted on by the hydrogen sulphide, so that it serves as an indicator, the filler now appearing black to the level to which the free hydrogen sulphide gashas passed. Instead of spraying, the absorbent can, ofcourse, be immersedin a solution of the. salt.

. r v v Where itis undesired or unfeasible to 1mseparate test or indicator stri 27 may be used, applied immediately bac of the window 23*, as shown in Fig. 3. This test strip vmay either be of a type which changes color when acted on by the gaseous impurity itself or when acted on by the product resulting from the absorption of the gaseous impurity by, or other actionupon thefiller. In the case of a canister for removing ammonia gas, embodying a filler of material that does not inherently change color after it has been used, such, for instance, as silica v gel, ordinary red litmus paper may beused,

. color to the level to which its contents has been spent.

During the actual use, in industry, of a canister, as for the protection from ammonia, chlorin, sulphur dioxide, hydroc mic or hydrochloric acid, a faint odor of t ese gases will apprise the user to change canisters, even if he should not look at the indicator, which in that case would appear to show that'the canister has been spent. In the case of a canister used for protection against carbon monoxide, however, or other poisonous gas that is odorless and tasteless, the canister should be looked at by the user from time to time during service, only the indicator in that case and neither the'sense of smell, taste, or any other sense or sensation, apprising of the need for changing canisters. Without my indicating means in the use of a canister operating in a-carbon monoxide atmosphere, the user might be seriously poisoned before he became aware of the fact that the canister is not func-.

tioning. Inasmuch asin the use of a carbon monoxide abstracting canister, the availability for further use should be almost constantly ascertained during actual service,

it might be-desirable to extend the indicator, not throughout the height of the canister, but only near the top thereof, the change in color or appearance duripg service, of such indicator, apprising ofthe need for changing canisters. A small mirror (not shown) is, therefore, advantageous, set at the proper angle to reflect the image of the indicator, so that it can be constantly seen, while the mask is in use.

My indicator -always apprises'of the need for replacing the canister, even though the latter may not be entirely spent, but by reason of rapid breathing, for instance, the impurity might only have acted on the surface of the granules throughout the hei ht of the canister and thereby have cause a change in color throughout the height of the window. I

When the canister thus used, is laid aside for-a period of hours or days, the granules which have only absorbed the gas at their surface, resume substantially the color or appearance of the unspent granules, by rea-' son of the im urity spreading throughout the volume 0 the granules, while those granules that have been saturated maintain the color or appearance of spent filler. Ac-

demarcation between the spent and unspent part thereof, visible through the Window. The user, accordingly, knows that it is still serviceable, where, in the absence of my indicating means, or separate testing appliances or operations, he would not feel safe in re-using a canister that had once apparently failed.

I have thus provided a reliable registering means for indicating the residual life of the canister and its availability at any instant for further use, which means is simple and easy to apply, which involves no delicate mechanism of any character, which avoids the use of special testing appliances or the need for disassembly of the apparatus, which does not depend for its operation T on temporarily inflicting discomfort or pain upon the user and which does not inipair the life of the canister. Should the canister drop and the glass window crack,

the celluloid pane therein remains intact and prevents the entry of air or gas through the crack, so that false reading is avoided.

Where a special chemical is used, near the top of the canister to produce a special noticeable physiological efl'ect, such as to excite the lachrymal glands, as a signal that the canister is no longer fit for use, it is apparent that there is no means available for indicating to the user, the extent to which the canister is still available, when, he is about to commence its use, so that after use but for a fraction of a minute, the signal may be given and the user is compelled to leave the gas-charged space and obtain a new canister. Moreover, the efliciency of the worker-is impaired, by the anticipation of the pain and discomfort to be inflicted and by the actual damage done when the alarm is given.

Where, on the other ,hand, two or more canisters are carried on the person with an inter-connecting valve for placing a used.

canister out of service and changing to a supposedly unused canister, not only is the apparatus more bulky and of greater weight, impairing the freedom of movement of the user, but, unless the connecting valve is particularly well made at substantial expense, it is likely to leak, so that as a matter of fact, the two canisters will to an extent be used concurrently and the supposedly fresh reserve canister may actually be spent or nearly spent, when the valve is set to bring it into use.

4 In the foregoing, .I have described two specific applications or embodiments of the invention suitable for ammonia and one for hydrogen sulphide gas masks. For abstracting sulphur dioxide, soda lime may be used as with hydrogen sulphide, with a separate indicating test paper, however, impregnated with potassium iodate starch .and applied substantially as in the embodiment of Fig. 3. For abstracting hydrochloric acid fumes, soda lime is also suitable, but as in its use for removing-sulphur dioxide or hydrogen sulphide, it does not change color. For this use, it is preferable to impregnate the soda lime with a Congo red solution which turns blue when acted on by hydrochloric acid fumes. For removing carbon monoxide gas, a suitable absorbent may be used, with palladium chloride test paper, serving as an indicator and turning dark under the action of carbon monoxide. Another suitable indicator for carbon monoxide is iodine pentoxide, sulphuric acid. The foregoing are illustrative examples merely of noxious gases and the indicators therefor with which my invention is concerned.

My invention is not limited in its application to industrial uses, but is suitable also in chemical warfare. In military'operations, thus, when the window or other in dicating area shows no more change, the soldier knows it is safe to remove the mask, and thus the dangers of premature removal, as well as the discomfort of continued use of the mask when no longer necessary, are obviated.

It will thus be seen that there is herein described apparatus in which the several features of this invention are embodied, and which apparatus in its action attains the various objects of the invention and is well suited to meet the requirements of practical use.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim v 1. A respirator canister having. an air inlet at one end thereof and an outlet at the other, a filler for said canister for abstracting a definite impurity 'from air drawn therethrough, said filter including a part extending substantially the distance between the ends of the canister and subject by contact with said impurity to change in appearsubstantially the entire length between said inlet and said outlet, means filling said canister and having an aflinity for an impurity to abstract the latter from air inhaled through the canister, and subject by contact with said impurity to change in appearance, whereby said window will visually indicate the region of demarcation between the spent and the unspent filler.

3. A respirator canister having an inlet at the lower and an outlet at the upper end thereof, a transparent portion extending substantially the height of said canister, a filler in said canister having a strong alfinity for a definite gas to abstract the latter as air charged therewith is drawn therethrough, said filler composition being of type to change color when acted upon by said gas, whereby theline of demarcation between the spent or used composition at the bottom and the available composition thereabove may be readily ascertained by inspection.

4. A respirator canister having a transparent portion extending the height thereof, a solid composition filling the same and having a strong aflinity for a definite gaseous impurity drawn through the filler with air, the composition combined with the-gas inter- .cepted thereby having a different appearance to the eye than prior to such combination, whereby a line of demarcation will appear between the spent part of the filler at the bottom of the canister and the unspent part thereabove.

5. A respirator for abstracting ammonia, comprising a canister having a transparent part extending substantially from one end to the other thereof, a filler of a metallic salt to form addition products with ammonia passed therethrough of color other than theuncombined salt, whereby the line of demarcation between the combined and the uncombined salt will indicate the residual life of the canister.

Signed at New York in the county of New I York and State of New York this 26th day of November A. D. 1924.

MAX YABLICK.

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