US 3716053 A
A breathing apparatus having a breathing mask which consists of an outer mask provided with eye pieces and an inner mask enclosing the mouth and the nose. A gas chamber is connected with the mask and is divided into two rooms. A first room comprises an inlet valve and is in direct gas fluid communication with the space between the outer and the inner mask, and a second room comprises an outlet valve and a membrance for controlling the inlet valve and is in direct gas fluid communication with the space inside the inner mask.
Claims available in
Description (OCR text may contain errors)
United States Patent 91 Almovist et al.
[451 Feb. 13, 1973 1 1 BREATHING APPARATUS  inventors: Hans O. Almovist, Lidingo, Sweden;
Sigurd A. Biicklund, Vasa, Finland  Assignee: AGA Aktiebolag, Lidingo, Sweden  Filed: March 12, 1971 2: Appl. No.: 123,708
 Foreign Application Priority Data March 12, 1970 Sweden ..3260/70  US. Cl. ..128/142.2, 137/63 R [51 Int. Cl. ..A62b 7/04  Field 01 Search ..128/l42.2, 42, 142.3145.8, 128/205; 137/63 R  References Cited UNITED STATES PATENTS 2,684,066 7/1954 Gldden l28/142.4 3,149,631 9/1964 Svenson..... 2,810,386 10/1957 Reed ..l28ll42.2
FOREIGN PATENTS OR APPLICATIONS 1.260.983 2/ 19611 Germany 1211/1422 764,111 12/1956 Great Britain ...128/142.2 3/ 1964 Netherlands 128/ 142.2
Primary Examiner-William E. Kamm Assistant Examiner-G. F. Dunne Attorney-Larson, Taylor & Hinds ABSTRACT A breathing apparatus having a breathing mask which consists of an outer mask provided with eye pieces and an inner mask enclosing the mouth and the nose. A gas chamber is connected with the mask and is divided into two rooms. A first room comprises an inlet valve and is in direct gas fluid communication with the space between the outer and the inner mask, and a second room comprises an outlet valve and a membrance for controlling the inlet valve and is in direct gas fluid communication with the space inside the inner mask.
2 Claims, 4 Drawing Figures \\\\\\\\\\\\XLY PATENIEDFEBIB I973 3.716.053
PRIOR ART F l6 2 IJJII INVENTOIS HANS O. ALMQVIST SIGURD A. BACKLUND n 0 62504 J y/W ATTORNEYS BREATHING APPARATUS BACKGROUND OF THE INVENTION The present invention refers to a breathing apparatus with a breathing mask which comprises an outer mask provided with eye ,pieces and an inner mask which is adapted to conduct the breathing gas to and from a user of the apparatus. Furthermore it is assumed that the breathing apparatus is of the kind in which the breathing mask is connected with a gas chamber having an outlet valve, a control membrane and an inlet valve controlled by the membrane.
When using breathing masks it has been found that it is desirable to let the inhalation gas flow past the eye pieces in order to prevent dimming of the eye pieces with moisture. Breathing masks intended for breathing in a noxious atmosphere have for this reason been provided with separate inhalation valves and exhalation valves so that the inhalation gas has been caused to pass through an inhalation valve in the outer mask, past the eye pieces and then into the inner mask through nonreturn valves on the inner mask. The exhalation gas has been conducted directly from the inner mask to the surrounding atmosphere through the exhalation valve. These known breathing masks have a comparatively high breathing resistance due to the combined resistance of the inhalation conduits, the inhalation valves and turbulence.
Breathing devices to be used both for breathing in a noxious atmosphere and for diving under water have been provided with a common inhalation and exhalation valve designed as a double valve. in this way it has become possible to mount the outlet valve near the pressure sensitive means of the breathing regulator so that they are not actuated by different'pressures atdifferent positions during diving under water. Breathing devices of this kind comprise a common gas chamber for the inhalation gas and the exhalation gas, said chamber also comprising an inlet valve and an outlet valve. In said gas chamber, however, the fresh inhalation gas is mixed with remainders of the exhalation gas which has stayed in the gas chamber. Since the exhalation gas always comprises of a comparatively large amount of moisture this arrangement has great disadvantages in case of gas flushing the eye pieces of the outer mask. The gas intended to flush pastthe eye pieces has in fact to be dry and the necessityto keep the gas dry is especially important when the breathing mask is to be used at low temperatures.
BRIEF SUMMARY OF THE INVENTION By the present invention the above indicated drawback is eliminated and furtheron the advantage is obtained that the inhalation resistance is reduced. This result has been obtained by dividing the gas chamber into two rooms which are substantially separated from each other. One room comprises the inlet valve and is in direct connection with the space between the outer mask and the inner mask, while the other room comprises the control m'embrane and the exhalation valve and is in direct connection with the space inside the inner mask.
DETAILED DESCRIPTION There follows a detailed description of a preferred embodiment of the invention, together with accompanying drawings. However, it is to be understood that the detailed description and accompanying drawings are provided solely for the purpose of illustrating a preferred embodiment and that the invention is capable of numerous modifications and variations apparent to those skilled in the art without departing from the spirit and scope of the invention.
FIGS. 1 and 2 are diagrammatic sectional plan views of a portion of previously known breathing devices;
FIG. 3 is a diagrammatic sectional plan view of a portion of an apparatus according to the invention; and
FIG. 4 is a diagrammatic sectional plan view of a portion of a modification of the breathing apparatus according to the invention.
With a gas chamber of the present invention the need of a combined exhalation and inhalation valve is eliminated. in this way the production of the mask is simplified and furthermore the function becomes more reliable since the number of movable parts has been reduced.
Another advantage of the breathing apparatus according to the invention consists therein that it can be provided with simple means for controlling the breathing pressure so that an overpressure, called safety pressure" can be upheld in the mask both during inhalation and exhalation. This result can be obtained by applying an adjustable load on the membrane which actuates the inlet valve. Furthermore, the outlet valve can be arranged on the membrane. v
ln a modified embodiment of the breathing apparatus according to the invention a connection is provided between the two rooms. in this way only a minor flow of fresh gas is caused to flush past the eye pieces and thereupon to pass into the inner mask. In this embodiment the inhalation gas will certainly comprise a part of the gas previously exhaled, but this is of no importance with regard to the dimming of the eye pieces with moisture, since this part of the inhalation gas does not pass the eye pieces.
FIG. 1 shows a breathing apparatus with an outer mask 4, and an inner mask 5. The space between the masks 4 and 5 is supplied with breathing gas from a gas chamber 1 through an inlet valve 2. The inhalation gas flushes past the eye pieces 8 on the outer mask 4 and into the inner mask 5 through non-return valves 6. The exhalation gas leaves the inner mask 5 through an outlet valve 3 and an outlet 9. This previously known apparatus is rather complicated and has a great number of movable parts. Furthermore it is suitable only for breathing in a noxious atmosphere.
FIG. 2 shows a previously known breathing apparatus which can be used both for diving under water and for breathing in a noxious atmosphere. It is provided with an inner mask 5 and an outer mask 4. This breathing apparatus has a gas chamber 1 provided with an inlet 16 for the breathing gas. This inlet may comprise an inlet valve controlled by means of a lever 17, by. a membrane mounted in a chamber 18. The chamber 18 may also comprise outlets for the breathing gas. In the connecting conduit between the gas chamber 1 and the space inside the outer mask and inside the inner mask a double valve 7 is arranged which allows the inhalation gas to pass at the periphery of the double valve 7 and which allows the exhalation gas to pass a latch formed member at the central part of the double valve 7. This function has been indicated by unfilled arrows for the inhalation gas and filled arrows for the exhalation gas. Thus, the inhalation gas passes the eye pieces 8 and then reaches the inner mask through the non-return valves 6.
in the breathing apparatus shown in FIG. 2 a remainder of the exhalation gas will stay in the gas chamber 1. This remainder will be mixed with the fresh gas and thereupon reach the space between the inner mask 5 and the outer mask 4. Since the exhalation gas is comparatively moist condensation will deposit above all on the eye pieces 8, especially if the temperature outside the mask is low and this will render the sight through the glasses difficult.
ln order to remedy this drawback with regard to the moist inhalation gas the breathing apparatus according to the invention has been designed as shown in FlGS. 3
and 4. The gas chamber 1 has been divided into two rooms 12 and 13 by means of a wall 14. The room 12 comprises an inlet valve 19 which may be loaded by a spring 20 and which is controlled by a membrane 21 in the chamber 18 over a lever 17. The membrane 21 is provided with openings 22 which are covered by an outlet valve 23. The exhalation gas reaches the surrounding through holes 24 in a lid 25. The outlet valve 23 may be formed by a rubber disk which is connected with the membrane 21 at the center so that the exhalation gas may pass at the periphery of the exhalation valve 23. 7
As a result of the dividing of the gas chamber 1 into two rooms 12 and 13 by means of the wall 14 only dry inhalation gas may pass the eye pieces 8, while all the exhalation gas passes directly from the inner mask 5 to the outlet in connection with the room 13.
The breathing apparatus shown in FIG. 4 is identical with the one shown in FIG. 3 but has been completed with a direct connection between the rooms 12 and 13 in the form of a hole 15 in the wall 14. The major part of the fresh gas passes into the room 13 since acertain over pressure is present in the room 12. The entire exhalation flow passes into the room 13. Due to the over pressure in the room 12 a certain flow of fresh gas is caused to pass the eye pieces 8 and thereupon into the inner mask, said flow of gas being sufficient to prevent deposition of moisture'ontheeye pieces.
During the inhalation a certain underpressure is created inside the membrane 21. The difference in pressure which occurs over the membrane gives a force which actuates theinlet valve 19 over the lever 17 so that a flow of gas is supplied to the user of the apparatus. The inhalation valve is so designed that a certain underpressure under the membrane gives a certain flow of gas. During the inhalation a fall of pressure appears in the inlet conduits and the inlet valves which directs the inhalation gas from the inhalation valve past the eye pieces and into the inner mask.
in the previously known breathing devices comprising a separate exhalation valve as shown in FIG. 1 or with a common gas chamber for the inhalation gas and the exhalation gas according to FIG. 2 an unnecessary great inhalation resistance occurs. This is due to the fact that the underpressure inside the inner mask, in order to give the desired underpressure under the control membrane, has to be equal to the sum of the underpressure under the membrane, the flow resistance in the outer mask and the valve resistance of the inner mask.
In the breathing apparatus according to the present invention this increased inhalation resistance has been eliminated since the inner mask is in direct connection with the control membrane through a conduit which also may be used as a exhalation conduit. In the apparatus according to the invention no flow of gas occurs in the conduit between the inner mask and the control membrane during the inhalation and accordingly there is no fall of pressure in said conduit.
As is apparent from the FIGS. 3 and 4 the flow of gas to the inner mask through the conduits and the valves takes place under the influence of the pressure in the supply conduit 26 connected to the inlet 16. Accordingly the fall of pressure in these conduits and valves cannot influence the inhalation resistance. This may also be expressed in such a way that the inhalation gas due to the pressure in the supply conduit 26 is 1 blown through the inlet valve and the conduits to the inner mask, whereby the resistance of the inner mask itself is eliminated.
What is claimed is 1. Breathing apparatus with a breathing mask comprising an outer mask and an innermask, the outer mask being provided with eye pieces and the inner mask for enclosing the mouth and nose of the user of the apparatus, and further comprising a gas chamber connected with the breathing mask, a wall dividing the gas chamber into a first and second room, the first room comprising an inlet valve and being in direct gas fluid connection with the space between the outer mask and the inner mask, the second room being in direct gas fluid connection with the space inside the inner mask, air inlet means opening into said first'room and outlet means opening into from said second room, a control member disposed in said second room between said inlet means and outlet means, an outlet valvedisposed between said control member and said outlet means, a lever connecting the member and the inlet valve for controlling the inlet valve, said lever being hinged in said wall and having one part in said first room and another part in said second room.
2. Breathing apparatus as claimed in claim 1 in which a hole in the wall forms a direct connection between the first and the second room.
UNITED STATES PATENT OFFICE CERTIFECATE OF CORRECTMN P n 3 716 053 1 Dated Februarv 13, 1973 Invent0r($) Hans O. Almqvist and Sigurd A. Backlund It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Claim 1, line 13, before "from" delete "into" Signed and sealed this 26th day of March 1971 (SEAL) Attest:
EDWARD M .FLETCI'IER, JR C MARSHALL DANN Attesting Officer Commissioner of Patents FORM PO-1050 (10-69) USCOMM DC 6o376 P69 fi' U.S. GOVERNMENT PRINTING OFFICE: 1959 0-866-334.