US2792000A - Face mask for use in dust-laden or other contaminated conditions - Google Patents

Description

R. J. RICHARDSON FACE MASK FOR USE IN DUST-LADEN OR OTHER CONTAMINATED CONDITIONS May 14, 1957 2 Sheets-Sheet Filed Jan. 18, 1954 v [710811 0! BIOHARD'J. mcumos ou B WW Attorney RICHARDSON FACE MASK FOR USE IN DUST-LADEN OR OTHER CONTAMINATED CONDITIONS May 14, 1957 2 Sheets-Sheet Filed Jan. 18, 1954 InUerl 0r RIGHARDSQN RICHARD J orneys FAQE MASK FOR 'USE'IN DUST LADEN"OR OTHER '(IDNTAMINATED (ZONDHTEDNS Richard John Richardson, Pontypridd,England, assignor toBISPF. A. Holdings'Limited,'Shethe-ld, England .Applicafion JannarylS, 1954,'Serial No. 4614538 Claims priority, application Great Britain January 20, 1953 '7 Claims. (Cl. 128-445) This invention relates to-face 'masks'foruse in atmosp'hericconditions that may be injurious 'to health or are "unpleasant, particularly atmospheres-that are-dust, fumeor vapour-laden.

his a serious disadvantage oftherespirator type of face'niask operating by filtration of contaminants from theair inhaled by the wearer thatbot'n the nose and mouth are enclosed, this resulting insuch real or fancied "discomfort that-an operative willeither refuse to wear ita, all or will. discard it at the;earliest opportunity. This means that protection is not obtained against-the effects of harmful or unpleasant atmospheres in many industries where the 'nature'of' the workmakes it inconvenient or undesirable for the operator'to wear 'the moreelaborate helmet equipment using a separate supply of uncontaminated air.

An important instance of this arises in the fertile-gshops of steel and'other fouridrieawhere; inspire of precautions to remove as much sand as possible irrknocking-outthe castings from their moulds, sand still 'a'dheringto -the "castings is pulverisedand becomes airborneduring'fettling "and cannot, depending'upon "the particular operation T being .perforrnei'be wholly rcmovedfrom the vicinity of .the operative'by exhausting equipment.

:Itis the object of the 'inventionto provide a mask giving 1a :high degree of, protection against the breathing 'of dust, ifurne,'or.otheriobjectionable atmospheric condition and yetrbeing comfortable to wear and convenient in use.

FACCOICllIlg tothe present inventioma face mask com- "prisesxacnose .piece'adaptedi..to:enclose'the nose and to extend aslarhood in frontof the upper lip, anda tube .passinginto. the space thus enclosed to serve for the intro- .duction .of uncontaminated Fall; into the breathing 'zone lyingbelow the space irr'which: contaminated atmospheric air. is excludedifrorn.Etheinostrils by the nose piece.

The nose piece may extend in front of the upper lip by curving in a single piece in conformity to the profile of the noseyor-iitmay'becprovidedwith:separate short hood to form the extension. In the 'former case, the tube preferably enters the enclosed space ata level above the nostrilsjin the latter case, the tube may enter the, part of i the space in front of'the upper lip.

Because of the barrier formed bythe noselplece, uncontaminatedlair introduced through the tubemust dispersemainly in adownward direction to' form a curtain in front of and below the mouth .and nostrils of the wearer so. that dust-laden oriotherwise. contaminated air is urged away from the wearer and breathing is'from the supply of uncontaminated air admitted through the tube. The sides of the hood may fit closely to the face at the sides of the nose and upper lip, to assist in the maintenance of the zone of uncontaminated air round the mouth.

The mouth itself is unencumbered, so that the operative does not feel restricted. There is no limitation on speech, and, if the hood does not fall below the level of the upper lip, smoking is not prevented. The enclosure r 2,792,000 "Patented May 14, 1957 ofthe nose does not prove objectionable, and the mask is free from the disincentives that make other forms of mask unacceptable.

ln order to increase'thecomfortable use of the mask, the'incorning air should not discharge in'theform of a jet. Preferably, therefore, the tube outlets-are covered by diffusing material. The 'quantityof air necessary to maintain the curtain may then escape into the hood substantiallyimperceptibly. Conveniently, a length of-the tube within the enclosed spa e has a closed end and has its 'wall generously perforated or slotted, avoiding discharge in the form of a jet but forming aprotectionfor an internal dispersingsleeve GP'Wad of suitable fabric or other. porous material.

The accompanying drawings show two forms of mask according tothe'inventionyboth including an eye shield through which some ofthc uncontaminated air is allowed ,to flow.

lnthe drawings:

"Figure 'l -is a front elevation of one form of mask, shown in the-position of use;

Figure 2 is a side elevation ,of the mask of Figure T;

Figure '3 is .asectionpn -the-line3-3 of Figure 1;

Figure 4 is afragmentary section onthe line 44 of Figure .3; and

Figures -5, 6 and '7 'areviews similarv toFigures 1, 2, and 3, but showing another form of mask,'Figure Tbeing .a sectiontaken on1.the line 7-7;of'Figure 5.

In Figures 1 to 3, a 'one piece'cye shield i ofplastic sheetgmaterial 'withpacurled rim-'11 carrying anedging 12 of 'sponge rubber 0r;the like to farm face closely, continues downwardly into "an integral nose piece 13, which follows: the; profile of-the wearers nose,,its lower end;14 extendingbelow'the IlQSB'IO leavea'fairly small gap MAY-in frontofthe upper lip above the level of the mouth. *The nose piece 13 and its extension '14 fit the face atthe sides of the nose and upper lip; the soft edging the-nose piece 13, an'internalbridge or support 15 with soft edging l6 is provided to bear on the nose, thus maintaining the'widthcf thespace l7, enclosedby the nose piecel3. Inst below the-bridge 15', transverse tube 18 is fitted (seeparticularly'Figure 4),",this entering at 9 one side of the nose 'piece 13,-where it is cemented into thewall and thickeningpieceltl. The other end 21 of "the tube'l 'is blanked ed, and cemented with a thickeningipiece'22 to the wall -of the nose piece. The protrudin-gendZS 'ofthe tube'18 receives afiexible air supply 'tube'24.

A wad 25 of porous material fills the tube 118 to produce a diifused fiow-of air'from the-outlet perforations 26: "Someoffthe-airpasses through'perforations 2'7 in -the'-b'ridge 1 5, toprevent ingress of dust Ol"0ll1,$1 contaminant to the neighbourhoodof the eyes and to prevent condensation on the inside of the shield. This air finally escapes through perforations 2S.

*Thegreaten part of the air, however passes over and round'nthe -n-ose an-d'through the gap MA to form a *curtain of air in frontofthe mouth. Assuming a breathing ra te of up --t-o 1 cubic foot -per-rninute (which is the=maximum li-k'e1y'to*bereached by an active :manual worker), a supply of air through the tube 18 at a rate of 3 cubic feet per minute produces such concentration of uncontaminated air about the nostrils of the wearer that the mask approximates to efiiciency if breathing is purely nasal. If the wearer uses mouth breathing alone, the curtain of uncontaminated air in front of the mouth makes the mask 70%80% efiicient, which means that the contaminated ambient air is largely prevented from coming into proximity to the mouth, in spite of the mouth itself not being covered by the mask.

The air supply tube 24 is secured to the mask by a clip 29 and is connected to an air supply system. The supply of uncontaminated air is adjusted to exceed continuously by a safe margin whatever maximum breathing rate is likely to be reached by the wearer, and may be taken from a low-pressure supply or a high-pressure supply. It the latter, the tube 24 is connected to a suitable reducing valve, and a filter should be interposed to preclude oil mist or other objectionable contaminants in the air-supply.

The mask as shown provides both breathing protection and eye protection. The one-piece eye shield serves for many operations, but separate windows or a single window, e. g. of reinforced or toughened glass, in an opaque shield body may be used if required. The mask is secured by tapes 30.

In Figures to 7, an eye shield 31 with a nose piece 32 much as in Figures 1 to 3 has the nose piece end just below the level of the nose. A hood extension 33 is cemented to the nose piece and continues to just above the level of the upper lip. A tube 34 enters one side of the extension 32 and continues to the other side underneath the nose. This is supplied by the flaxible tube 35 clipped at 36 to the eye shield. The tube 34 is filled with porous material 37 to act as a diffuser for the outlets 38.

Air emerging below the nostrils forms a curtain over the mouth as it escapes below the edge 39 of the hood extension 33. Some air passes upwardly over the nose into the eye space, finally escaping by perforations 40.

What I claim is:

1. A face mask comprising a nose piece adapted to surround the nose and to enclose the upper part and sides of the nose, with the lower part of the nose piece extending downwardly as a hood in front of and clear of the upper lip, where it ends short of the mouth to leave a clear and direct passage to the atmosphere, and a tube passing into the nose piece to serve for the introduction of uncontaminated air into the breathing zone of the nostrils, with the clear passage providing for the escape of the air as a curtain in front of and below the mouth of the wearer.

2. A face mask comprising a nose piece adapted to surround the nose and to enclose the upper part and sides of the nose, with the lower part of the nose piece extending downwardly as a hood in front of and clear of the upper lip, where it ends short of the mouth to leave a clear and direct passage to the atmosphere, and a tube passing into the nose piece, the tube within the nose piece being perforated and filled with porous material, whereby uncontaminated air may be introduced in diffused manner into the breathing zone of the nostrils, with the clear passage providing for the escape of the air as a curtain in front of and below the mouth of the wearer.

3. A face mask comprising a nose piece adapted to surround the nose and to enclose the upper part and sides of the nose, with the lower part of the nose piece extending downwardly as a hood in front of and clear of the upper lip, Where it ends short of the mouth to leave a clear and direct passage to the atmosphere, together with an eye shield connected internally with the nose piece, and a tube passing into the nose piece to serve for the introduction of uncontaminated air into both the nose piece and the eyeshield, escape openings in the upper part of the eye shield permitting some flow of the air through the eyeshield, but the clear passage in front of the upper lip providing for free escape of air as a curtain in front of and below the mouth of. the wearer.

4. A face mask comprising a nose piece adapted to surround the nose and to enclose the upper part and sides of the nose, with the lower part of the nose piece extending downwardly as a hood in front of and clear of the upper lip, where it ends short of the mouth to leave a clear and direct passage to the atmosphere, together with an eye shield connected internally with the nose piece, and a tube passing into the mask between the nose piece and the eyeshield to serve for the introduction of uncontaminated air into both the nose piece and the eyeshield, escape openings in the upper part of the eyeshield permitting some flow of the air through the eyeshield, but the clear passage in front of the upper lip providing for free escape of air as a curtain in front of and below the mouth of the wearer.

5. A face mask as in claim 4, comprising an internal bridge to bear on the nose, the air tube being disposed below the bridge, and perforations being provided in the bridge to admit air to the eyeshield.

6. A face mask comprising a nose piece adapted to surround the nose and to enclose the upper part and sides of the nose, with the lower part of the nose piece extending downwardly as a hood in front of and clear of the upper lip, where it ends short of the mouth to leave a clear and direct passage to the atmosphere, together with an eyeshield connected internally with the nose piece, and a tube passing into the nose piece in front of the upper lip to serve for the introduction of uncontaminated air into the nose piece and the eyeshield, escape openings in the upper part of the eyeshield permitting some flow of the air through the eyeshield, but the clear passage in front of the upper lip providing for free escape of air as a curtain in front of and below the mouth of the wearer.

7. A face mask comprising a nose piece adapted to surround the nose and to enclose the upper part and sides of the nose, with the lower part of the nose piece extending downwardly as a hood in front of and clear of the upper lip, where it ends short of the mouth to leave a clear and direct passage to the atmosphere, together with an eyeshield connected internally with the nose piece, and a tube passing into the nose piece in front of the upper lip, the tube within the nose piece being perforated and filled with porous material, whereby uncontaminated air may be introduced in diffused manner into the breathing zone of the nostrils and to the eyeshield, escape openings in the upper part of the eyeshield permitting some flow of the air through the eyeshield, but the clear passage in front of the upper lip providing for free escape of air as a curtain in front of and below the mouth of the wearer.

References Cited in the file of this patent UNITED STATES PATENTS 428,592 Chapman May 27, 1890 771,801 Andrew Oct. 11, 1904 1,191,274 Brayton July 18, 1916 2,468,383 Tifiany Apr. 26, 1949 2,764,152 Osterberg Sept. 25, 1956 FOREIGN PATENTS 492,723 Great Britain Sept. 26, 1938

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