US2671528A - Air purifier - Google Patents

Description

March 9, 1954 w E GROSS 2,671,528

AIR PURIFIER Filed Jan. 25, 1944 MAL/4M. eoss Patented Mar. 9, 1954 AIR PURIFIER William E. Gross, Joppa, Md., assignor to the United States of America as represented by the Secretary of War Application January 25, 1944, Serial No. 519,597

2 Claims. (Cl. 183-49) (Granted under Title 35, U. S. Code (1952),

sec. 266) The invention described herein may be manufactured and used by or for the Goverment for governmental purposes without the payment of any royalty thereon to me.

This invention relates to apparatus for filtering and purifying air containing noxious gases, vapors and/or smokes; more particularly, it relates to a canister used in connection with gas masks and the like.

In order to render contaminated air fit for breathing, it has been the practice to use a gas mask with a connected canister, whereby all inhaled air must first pass through the canister to be filtered and purified therein.

Fundamental requirements of air-purifying canisters are: inexpensive manufacture, limited use of critical materials, light Weight, compactness, and efficiency in air purification.

Although many varieties of air purifiers are known to have been developed, there has been need for improvements with which this invention is concerned.

One object of tihs invention is to simplify and improve the construction of gas mask canisters so that they more satisfactorily meet the f fundamental requirements.

Among more specific objects, this invention provides an air purifier improved in the following respects: (a) by minimized internal structure, particularly with avoidance of parts attached inside the canister; (b) prevention of channeling by use of a resilient medium that also functions as a smoke filter; and (c) protection of the air purifier filling from water, moisture, and oil aerosols. These and other objects will be apparent from the following description and accompanying drawing.

In the drawings are shown two modifications of canisters embodying features of the invention. The same reference characters refer to like parts.

Figure 1 diagrammatically illustrates a side elevational cross-section view of one canister modification.

Figure 2 illustrates an elevational side view of another canister modification partly in section.

Referring particularly to the drawing, the canister comprises an outer gas-tight and waterproof casing or body I which may be made of sheet metal. The body may be cylindrical or box shaped.

Referring to Figure l, the body I is crimped or double-seamed in tight engagement with cover 2 that is perforated and preferably dished inwardly. As shown in Figure 2, the inlet cover 2 may be detachably fitted to the body by screwing, bead and slot engagement, or a friction fit so that the canister filling may be readily removed and renewed.

At the outlet end in the upper part of the canister, shown in Figure 1, the body is tightly engaged by double seaming to a valve holder support 3 having an outwardly formed bead or rim 4 to facilitate secure attachment to a facepiece. Alternatively, as shown in Figure 2, the canister body may be drawn to a narrowed neck 5 threaded for securing into an adapter, a corrugated hose, or valve holder on a facepiece.

Valve seat 6 which is securely engaged to the support 3 has air outlet ports 'l and a central aperture 8 through which is passed a connecting button or fastener 9 that holds the check valve disc IB. The check valve disc Ill made of rubber or any similar iiexible plastic material is normally seated so that it closes the ports 'l except when air is being inhaled through the canister.

A perforated retainer II, preferably dished inwardly, is disposed above the filling in the canisters and rests against the shoulder at the upper part of the body. Advantageously, this retainer does not have to be rigidly secured or fastened inside the canister. It may have a snug fit or a loose fit so that it more or less fioats on the lling and can be readily removed or placed back into the canister on assembly or in making repairs.

Between the perforated inlet cover at the bot-- tom and the perforated retainer II are placed in the order, as shown in Figure l, a layer or pad I2 of highly resilient rock-wool; a decontami-l nating layer I3 comprising well known chemical agents including charcoal, which physically adsorbs, chemical absorbs, or neutralizes noxious gases; and a layer or pad I4 of fairly resilient rock-wool.

A feature of this invention is that a resilient fibrous inorganic material, particularly one like rock-wool, which is not affected by water, keeps the granular air-purifying material tightly packed, thus serving to eliminate the need of a spring or other means for preventing loosening and channeling.

When the rock-wool is highly resilient, it

usually has a fair smoke filtering action; and when it is moderately resilient, it usuallyhas j;

a very good smoke filtering action, although ,it

does not have suficient resiliency to maintain granules of the chemical filling in a compact condition during a, rough usage test. '.Iests showed that the canister could stand a rough usage test if a pad of highly resilient rock-Wool is placed on one side of the chemical lling and one pad of the less resilient rock-wool is placed on the other side', thustsandwicliing1 the; chemical 5 lling. Thiscombination'resultedin better smoke protection than when both pads were of the highly resilient rock-wool. As a chemical filling in layer I3 there may 'be used activated charcoalf.,.-

impregnated charcoal, such as Whetlerite, soda-- lime, Hopcalite and various;othersfsubstancese. alone or in combinations fornremoving'fgaseousrs contaminants by chemical and/or physical action. For simplicity, these chemical agentsare. l.

herein referred to as absorbents.` The chemical lling may be made up of one or morez'layers; As illustrated in Figure 2, waterproolter.

paper may be placed on both sides' 'of thechemief cal lling, i. e., for example, at I5 adjacent the retainer II above the resilient filter medium I4 20 protected-on '-bothf sides t from `-waterwl On`^the outlet side*the'chemical-'llingis protected'-fromsaliva and on the inlet side itis protected from` entrance of-*raing-'for the entrance of-water on 2 Ail* renderednoxious bythe gas or smoke entersA theicanist'er through the perforated -lower cover-1` 2, 4'passesthrong-h" the 'highly resilient' rock-Wool smokelt'er AI 2 :then -through 'the' chemical filter-- inga-bsorbent I=3through the resilient-smoke lter- I 4, andup throughthe outlet or check-valve ports 1 'I into a hose;adapterfor-suitabie facepiece.

The simplified canister requires a minimumuse 1offmachii'iery,` critical material such=as steel, and-'skilledelabor Afor'fits :production: It i readily len-cls"1 itself lto f manufacture from lnon-metallic materials, 'such`-as"plastics; -and .even-if made frm- *nf1etal,'` a relatively small amount of metal is iused. 2 Byf virtueiof :the tough resilient f nature of the filtering meditimfmade'of a' material such "f as-@rock-L'vvool, the'canister--does not require 'the'50 ing-)rough usage, as contrasted withf conventionalcanisters that require a fairly hard absorbent to-` prevent-ninger'griningduring rough handling. Tli"e" canisterfcanJ befreadily assenfrbledf- 'repaired' c' andr-enewedbyRunskilld'personnel'f ltepadslimay 'beieutfovepsize so that when4 installed "inlathe canisterf the'yf'expand against the sides and prevent contaminated--'air1from-V channeling-aroundithe edges; as `contrastedfyvith conventionakcanisters thatfrequire sealing-'of' 70 ltere-materials 'atth'eA edges-inside thev4 canister ini'orderlto:preventchannelingr# Also, by use'of the resilint'lter Y medium, the' air ofw'is 4evenly distributed over thecross-sectional'area ofthe absorbent"layeru and thus 'dispenses-with the use 75 of baffles and other internal structure generally required in conventional canisters.

Complete engineering tests on canisters constructed in accordance With the present invention prove-'the canister to ibe sati'sfactoryiinjevery Way. The -chemical filling-was placedain the canisters between the resilient iilter medium pads without having to use expensive vibrating presses or similar devices for strongly compacting the chemical absorbent in order to prevent deformation. andrchannel-irig-,during rough usage. The rockewoolwltergwasefound to be unaffected by exposure ftooilbvapor. or smoke. Canisters were actually submerged in Water for a substantial period without subsequent damage. When subjectsztorough usage, no appreciable effect was made on their performance.

With-the" simplified design, the canisters may 13e-adapted for use with civilian masks, training masks, various service masks and with industrial masks?` or other-f protective'.v respiratory devices L in largef-quantitiesfat low costs.:

It is tobe-understood .-thatzthe invention is not.` limited to details of construction, herein shown :l 5 byway zofdllustration; smcefvariationsgxvill,readily .occuri-.to those skilled: in the .art iwithoutvdeparting rommheiispirit: of thezinvention; or `err- V ceeding 1the :scopef :thezzappended: claims.

I claim:

1. A gas :maskvcanist'erz cylinder: thatwincludes in combination :i a pair of f oversize :diameter lter pads paokedzinto'said `canister .cylinder :and held in lateral compression therebyesaidnpads being'; composed of mineralfWoolacharacterizedV by its resilience; -a decontaminatingflayer:held in comT pression between f said: pads-.1. solely by, ,vsaidr re silience; -1 and' l'iwiterproof lter=r1neansarranged to arrest the entrancerof moisturefat eachr end of: said kcanisters/1l 2. .Aniaxial-low air, purifier comprising a container-f a :iillerefa perforated' fixed ,inlet-plate; i a perforated oating outlet plate; a valve; meana.

maintaining-said valveJ-inisealed communication withf. said .-outlet plate;;.-rwaterpr oof' xlter means at each. end tof saidscontainerarrangedy -to farrestl the entrance of moisturef-intosaid ii1ler;--said,4

llerfconsistngzoffa Ipair Ofrmineral-wool lter pads.-icharacterizedf'by .their resilience :and held.

underlateral ncompression-fin said .container ;r and a layer-ofdecontaminating material held between said pads:inicompressionI exertedl Asolely by said resilience. r

WILLIAM" E. GROSS.

References. Cited inthe lel'of this patentf UNITED STATES PATENTS Number r Name -Y Date 1,395,833? Kliri'get'al. Nov. 1, 1921 1,499,864r Gordon- July 1, 1924 1,743,675 Jordahl Jan.'14, 1930 1,789,262?? Monroret-ah Jan. 13, 1931 1,8663659 Litle, Jri'; July- 12, 1932 1,889,015 Davis Nov; l29,1932 1,963L8T74f-1 Stampe-s. June 19, 1934 2,225g990 F1 Henry s Dec. 24, 1940 2,273,779 Dickey et al. Feb. 17, 1942 2,283,0,430'1 Busch May 1'2, 1942 2,302,809? Shoeldt'; Nov;V 24, 1942 2,400,7191-x Stackhouse May 21, 1946A FOREIGNFPATENTS f' Number= Country v Date 365,478 GreatBritain Jan'..2l, 1932, 510,985 Great Britain Aug. 11, 1939

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