US2551653A

US2551653A - Oxygen mask for pressure breathing

Info

Publication number: US2551653A
Application number: US647410A
Authority: US
Inventors: William A Wildhack
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-02-13
Filing date: 1946-02-13
Publication date: 1951-05-08
Anticipated expiration: 1968-05-08

Description

May 8, l951 w. A. WILDHACK 2,551,653

OXYGEN MASK PRESSURE BREATHING Filed Feb. 13, 1946 William A Wild/JOCK Patented May 8, 1951 William A. Wildhack, Arlington, Va.

Application February 13, 1946, Serial No. 647,410

16 Claims.

(Granted under the act of March 3, 1883, as

This invention relates to breathing masks and more particularly to oxygen masks having valve systems for pressure breathing.

This invention may be found of value not only in the field of aeronautics, where it may become necessary for an aviator to use oxygen, but also in the administration of other therapeutic gases including air, in conditions where intra-tracheal or intra-pulmonary pressures are indicated, as, for example, the relief of asthmatic choking, pulmonary edema, or unrelieved pressure on the middle ear.

Accordingly, it is a primary object of this invention to provide a new and improved breathing mask.

Another object of the present invention is to provide a new and improved valve system in'oxygen masks for pressure breathing.

Another object is to provide an efficient and automatically adjustable balanced valve for exhausting the expired gases in a pressure oxygen supplied gas mask.

Other and more specific objects will appear in the following detailed description of one illustrative form of device built in accordance with the present invention, having reference to the accompanying drawings wherein:

Fig. l is a partly diagrammatic illustration of a preferred embodiment of the invention; and

Fig. 2 is a perspective view of this embodiment of a gas mask incorporating the novel balanced valve system of the invention.

Referring now to the drawings for a more complete understanding of the invention, in which like reference characters are used throughout to designate like parts, and in particular to Fig. 2 thereof, the mask generally designated 23 is observed to have an inlet portion I!) connected by duct portion II to a conduit 6 which it is understood is connected to a suitable source of gas under pressure, not shown. The collar I2 of conduit 6 slips over the neck of duct portion I I, Fig. 1, forming a substantially hermetical seal therewith. The mask includes a nasal passage portion 8.

Particular reference is made now to Fig. 1, a cross sectional view of a mask similar to that of Fig. 2. The duct I8 disposed within the aforementioned nasal passage portion 9 conducts gas under pressure from inlet chamber I to a check or one-way valve 8 mounted in a base I3, which is preferably composed of rubber, and is located in wall 24, the direction of gas flow being indicated by the arrows. Gas, after passing through valve 8, is breathed in by the person wearing the mask.

The mask has an exhaust valve mounted within aperture 20 in a central supporting portion thereof. The valve comprises a housing generally designated by the reference numeral 4, having an annular recessed portion I9 for receivamended April 30, 1928; 370 O. G. 757) ing the lip 2|, and being maintained in place thereby. Around the periphery of the housing 4 are exhaust apertures 22 for the escape of used gases into orifice portion I6 and thence from vent II, Fig. 2, and the housing has a short pipe portion 1 extending through hole or aperture I I. Means, not shown, may be provided for insuring that the pipe portion I forms a hermetical seal with the wall of the hole I4 through which it extends.

Disposed within the housing 4 is a cell or bellows generally designated 3, having flexible wall portion 5, and having a lip 2, which, when the bellows is expanded, presses against the adjacent lip I of the housing, forming a substantially hermetical seal therewith.

In the operation of the above described apparatus, the pressure of gases breathed out by the person wearing the mask causes the bellows to contract, and the gases escape through the opening thereby caused between aforementioned lips I and 2, the direction of movement of this gas being indicated by the arrows within the housing, Fig. 1.

The areas of the lip I, and of the lip or lid 2 of the compensating cell 3, are so adjusted that when the same pressure is applied to both sides of the valve it remains closed with a slight force; but when the pressure on the bottom of the valve (or the upper side as viewed in Fig. 1) exceeds the pressure in cell 3 by a few tenths of an inch of water, the valve opens.

To make possible an increase in mask pressure without a simultaneous increase in the compensating cell pressure, which would prevent the valve opening, the aforementioned inlet check valve 8 is installed in the mask near the region 01 the duct I8 designated I0, terminating the aforementioned inlet duct I8 from the breathing tube 6.

In the manufacture of balanced valves of the type herein employed, it may be preferable to use an integrally formed bellows or a simple diaphragm. Where a bellows is employed, it is desirable that the efiective area of the bellows wall should not change too much with the valve opening, and that the bellows be not too stiff. It may be desirable to use a light spring, not shown, for urging the valve closed, or to omit the mechanical spring if the initial compression of the bellows or other pressure responsive element provides some closing force on the lip which controls the valve opening. The dimensions of the frame or housing 4 may, of course, be varied to suit the mask; the diameter of the valve itself should be adequate to permit rapid exhalation without excessive resistance.

In the design of the mask, the relation between the excess pressure in the mask and the rate of exhaust flow depends on and may be controlled in various ways by several factors; the differential or unbalanced area affected by pressures on the two sides of the valve; the spring loading, if any; the annular area of the valve lid or lip outside the valve seat area; the clearance between the valve lid and the adjacent portions of housing 4; and the position and area of the exhaust vents.

The apparatus of the subject invention is especially well adapted for use where the delivery pressure from the oxygen pressure regulator, not shown, is very small or even slightly negative with respect to the ambient atmosphere. In this condition, which is frequently employed in aeronautics, the regulator is adjusted not for pressure breathing, but only to supply oxygen upon demand, 1. e., upon a slight suction. The differential area acted upon by the suction tends to open the valve, and it is desirable to provide a mechanical loading, not shown, (e. g., a spring, or resilience of the pressure responsive element), sufficient to hold the valve closed under the operating suction.

In the construction of the apparatus, the check valve 8 should preferably be of a type which inakes a positive seal; leakage may cause the pressure in the delivery tube and compensating cell to build up, preventing the opening of the balanced exhaust valve. A rubber flap valve,

with a slight positive opening pressure, is indicated as probably the best type.

The above described apparatus, then, embodies the aforedescribed advantages of the invenit significantly, since it is connected to the much larger volume of the delivery tube and regulator, and the regulator, not shown, preferably has an elastic wall.

Obvio ly many modifications and variations of the present invention are possible in the light of the above teachings It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

This invention may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A pressure breathing gas mask comprising a suitable casing having an opening for applica tion to the face of the breather and gas inlet and outlet passages, a check valve in said inlet opening inwardly and a balanced valve comprising a bellows having a flexible wall in said outlet responsive to a pressure differential between the pressure in said inlet passage and the pressure in said outlet.

2. A gas mask having an inlet and outlet, a delivery passage connected to said inlet, a check valve in said inlet opening inwardly, and a balanced valve comprising a bellows having a flexible wall in said outlet responsive to pressure in said delivery passage for freely opening whenever the pressure in the gas mask is slightly raised over that in the delivery passage.

3. A gas mask having a single breathing chamber with a delivery passage and an exhaust passage, a check valve in said delivery passage and a pressure controlled exhaust valve in said exhaust passage, a pressure cell comprising a bellows having a flexible wall for normally closing said exhaust valve in response to pressure in said delivery passage, said bellows providing light resilient means for urging the exhaust valve into a closed position whereby the valve will maintain its seat when the pressures are equalized and will open upon a slight increase in the pressure in the gas mask over that in the delivery passage.

4. In a pressure ga mask having a gas supply conduit, an outlet for the exhaled gases to the atmosphere having a balanced valve comprising a bellows having a flexible wall, means for applying the pressure in the supply conduit to said bellows to urge said valve in a closing direction, said flexible wall normally furnishing an additional light resilient force to said valve in the closing direction.

5. In a pressure gas mask, a breathing chamber for direct communication with the mouth and nose of the breather, an inlet chamber communieating with the gas supply, an outlet chamber communicating with the atmosphere, an inlet check valve between said inlet chamber and said breathing chamber normally held closed by a light spring, an outlet valve between said breathing chamber and said outlet chamber normally held closed by light resilient means, said resilient means comprising a bellows having a flexible wall, and additional closing pressure means connected to said inlet chamber, whereby to maintain the differential opening pressure of said outlet valve substantially constant regardless of pressure variations in said inlet chamber.

6. In a pressure gas mask, a breathin chamber, an inlet chamber connected to the gas supply, an outlet chamber opening into the atmosphere, an inlet check valve between said inlet chamber and said breathing chamber, an outlet valve between said breathing chamber and said outlet chamber normally held closed by light resilient means and having a movable valve element comprising an end wall of an expandable chamber connected to the inlet chamber, said end wall being exposed on its inner side to the pressure in the inlet chamber and on its outer side to the pressure in the breathing chamber, said resilient means comprising a bellows having a flexible Wall.

7. In a pressure gas mask, a breathing chamber, an inlet chamber connected to the gas supply, an outlet chamber opening into the atmosphere, an inlet check valve between said inlet chamber and said breathing chamber, and an outlet valve between said breathing chamber and said outlet chamber normally held closed by light resilient means and having a movable valve element exposed on its outer side to the pressure in the inlet chamber and on its inner side to the pressure in the breathing chamber, said resilient means including a bellows having a flexible wall, the area of the movable element exposed to the pressure in the inlet chamber being slightly greater than that exposed to the breathing chamber when the valve is closed, whereby equal pressures on opposite sides of said valve will normally maintain it in the closed position.

8. A pressure breathing gas mask comprising a suitable casing having a chamber for application to the face of the breather and gas outlet and inlet passages connecting with said chamber, a check valve mounted in said inlet passage and opening inwardly while the pressure in said inlet passage exceeds the pressure in said chamber, and a balanced valve in said outlet passage Iresponsive to a pressure dillerential between the pressure in said chamber and the pressure in said inlet passage.

9. A gas mask having means forming a breath ing chamber and an inlet and outlet for the chamber, means forming a gas delivery connected to said inlet, a check valve in inlet opening inwardly into the chamber, and a balanced valve in said outlet responsive to a pressure differential between a first pressure in breathing chamber and a second pressure in said gas delivery passage, said balanced val e constructed and arranged to open outwardly from the breathing chamber when the first pressure exceeds the second pressure by a prede-- termined amount.

10. A mask according to claim 9 wherein said balanced valve comprises a flexible member of predetermined dimensions whereby the relative areas thereof exposed to the first and second pressures provide for valve operation responsive to the pressure differential.

11. A gas mask comprising a suitable casing having a chamber for application to the face of the breather and gas outlet and inlet passages connecting with said chamber, a check valve mounted in said inlet passage and opening inwardly while the pressure in said inlet passage exceeds the pressure in said chamber, and a differential pressure operated balanced valve in said outlet passage and communicating with said inlet passage, said balanced valve comprising a mow able member of predetermined dimensions whereby the relative areas thereof exposed to the pressures in the chamber and inlet passage provide for opening the balanced valve outwardly to permit the escape of gas when the pressure diiferential reaches at least a predetermined value.

12. A gas mask having a single breathing chamber with a delivery passage and an exhaust passage, a check valve in said delivery passage and a differential pressure controlled exhaust valve in said exhaust passage, means connecting said exhaust valve with the delivery passage, said exhaust valve including light resilient means for urging the exhaust valve into a closed position whereby the exhaust valve will maintain its seat while the pressures in the chamber and delivery passage are equalized and will open to permit the escape of gas upon a slight increase in the pressure in the breathing chamber over that in the delivery passage.

13. In a pressure gas mask having a gas supply conduit, an outlet for the exhaled gases to the atmosphere having a balanced valve connected to the gas supply conduit and responsive to a pressure differential between the pressure in the mask and the pressure in the supply conduit, said balanced valve including means for applying the pressure in the supply conduit to the outside of said valve to urge said valve in a closing direction, said balanced valve including means normally furnishing an additional light resilient force to said valve in the closing direction.

14. In a pressure gas mask for use with a gas supply, means forming a breathing chamber for direct communication with the mouth and nose of the breather, an inlet chamber communicating with the gas supply, and an outlet chamber communicating with the atmosphere; an inlet check val e between said inlet chamber and said breathing chamber normally held closed by a light spring; and a differential pressure operoutlet valve between said breathing chamber and said outlet chamber normally held closed b light resilient means, said outlet valve includi additional closing pressure means connected to said inlet chamber whereby to maintain the differential opening pressure of said outlet valve substantially constant regardless of pressure variations in said inlet chamber.

15. In a pressure gas mask for use with a gas supply, means forming a breathing chamber, an 'nlet chamber connected to the gas supply, and an outlet chamber opening into the atmosphere; an inlet check valve between said inlet chamber and said breathing chamber; and a diiferential outlet valve between said breathing chamber and said outlet chamber normally held closed by light resilient means and having a movable valve element exposed on its inner side to the pressure in the inlet chamber and on its outer side to the pressure in the breathing chamber; and adapted to open the valve to permit the escape of gas when the pressure in the breathing chamber exceeds the pressure in the inlet chamber by a predetermined amount.

16. In a pressure gas mask for use with a gas supply, means forming a breathing chamber, an inlet chamber connected to thegas supply, and an outlet chamber opening into the atmosphere; an inlet check valve between said inlet chamber and said breathing chamber; and a differential outlet valve between said breathing chamber and said outlet chamber normally held closed by light resilient means and having a movable valve element exposed on its outer side to the pressure in the inlet chamber and on its inner side to the pressure in the breathing chamber, the area of the movable element exposed to the pressure in the inlet chamber being only slightly greater than that exposed to the breathing chamber when the valve is closed, whereby quick opening is obtained when exhaling in the breathing chamber increases the pressure therein over the pressure in the inlet chamber.

WILLIAM A. WILDHACK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 680,419 Schaefier Aug. 17, 1901 1,503,970 Guillemard Sept. 16, 1924 1,509,319 Saunier Sept. 23, 1926 1,691,648 Drager Nov. 17, 1928 2,168,695 Asari Aug. 8, 1939 2,453,475 Tobias Nov. 9, 1948 FOREIGN PATENTS Number Country Date 292,531 Great Britain Mar. 7, 1929