US2387123A - Breathing apparatus - Google Patents

Description

Oct. 16, 1945. G, M. DEMING BREATHING APPARATUS Filed April 5, 1941 2 Sheets-Sheet l INVENTOR George M. Dem/r1 ATTORNEY Oct. 16, 1945. G, M D WNG 2,3 7,123

BREATHING APPARATUS Filed April 3, 1941 2 Sheets-Sheet 2 'INVENTOR George M Dem/n ATTORNEY PatentedOct. 16, 1945 NITED BREATHING APPARATUS George M. Deming, East Orange, N. J., assignor to Air Reduction Company, Incorporated, New

York, N. Y., a corporation of New York Application April 3, 1941, Serial No. 386,618

This invention relates to breathing apparatus, and more especially'to apparatus for supplying oxygen .to aviators at high altitudes, though some features of the invention can be used with other apparatus for administering gas generally.

When supplying oxygen to aviators, the proportion of oxygen must be increased as the altitude becomes greater, until at very high altitudes the aviator breathes pure oxygen. Manual control'means were formerly employed to change the-oxygen supply in accordance with the needs of the aviator, but such a control of the oxygen supply is unreliable and may at times be dangerous.

In order to obtain more reliable variation in the oxygen supply with changes in, altitude, .ap-'

paratus was developed in which a flow of oxygen was regulated by aneroid control means. With such a control the oxygen is entirely shut off at low altitudes and the apparatus opens progressively as altitude increases.

It is an object of this invention to provide an improved breathing apparatus in which the supply of oxygen is automatically controlled in accordance with the altitude. It is a feature of the invention, however, that instead of supplying predetei nined quantities of oxygen at the various altitudes, the oxygen supply is made dependent upon the requirements of the individual aviator.

This result is attained by supplying only as much oxygen as is necessary to maintain the pressure in a breathing mask at the pressure of the surrounding atmosphere. Air can enter the mask through an opening that leads to the surrounding atmosphere, but the amount of air that enters the mask im this way to dilute'the oxygen is decreased by means of an aneroid-controlled valve.

o Claims. (or. 128-142) or at least greatly retard his satisfactory adapta-.

In this way the proportion of oxygen supplied to maintain the pressure in the mask is progressively greater as the altitude increases. a v

" There are a number of advantages in controlling the supply of oxygen in the manner employed by this invention, because the oxygen for any given altitude varies greatly according to the size, mental state and physical activity of the individual; It has been ascertained, for example, that a flow rate may be set which is entirely adequate to meet the physiological requirements of the individual and yet if the individual takes a sudden deep breath, as a result of excitement or possibly becauseof lack of familiarity and there fore confidence in breathing by means of an oxygen mask,- the failure to take into his lungs tion to mask breathing. With' this invention there is no predetermined supply of oxygen, but the supply. of oxygen is automatically replenished during inspiration so as to maintain the pressure in the mask substantially the same as that of the surrounding atmosphere.

With this invention oxygen flows whenever the aviator inhales, but ceases to flow during the process of expiration and intermediate period known as the respiratory pause. Obviously by such an arrangement, a large individual or one who attempts to breathe deeply will automatically be supplied with more oxygen than a small individual breathing normally. It will be obvious that such an arrangement necessarily leads to considerable economy in the use of the oxygen. Tidal volume, that is, the amount of air or oxygen taken into the lungs, varies as much as ten to one according to the size of the individual and the degree of physical activity or respiratory exertion involved. Consequently, unless the flow rate is automatically adjusted to the actual respiratory process, considerable excess oxygen must be supplied.

Except at high altitudes where the aviator must breathe pure oxygen, the interior of the maskcommunicates with the atmosphere through a valve-controlled opening in the side of the inask. This valve is operated in accordance with changes in the barometric pressure to progressively close the opening so that less air is drawn in to dilute the oxygen as the atmospheric pressure drops off at increasing altitudes.

I have found that it is not suflicient to main- -by one who has not previously used an oxygen breathing mask. Iiin'd that the pressure difierence between the inside of the ,mask and the surrounding atmosphere should not be substanas much oxygen as the lungs require when sudtially greater than that of a one-tenth of an inch water column, and preferably not more than onehalf this amount. The improved regulator apparatus of this invention can maintain a pressure in the mask that does not vary more than plus or minus .05 inch of water. Other objects, teatures and advantages of the invention will appear or be pointed out as the specification proceeds.

hereof:

In the accompanying drawings, forming .part

Fig. 1 is a side view, mostly in section, showing an aviation breathing mask embodying the invention.

Fig. 2 is a rear view, mostlyin section on the line 22 of Fig. 1.

The mask It includes a-metal shield H with a cushion l2 that is filled with soft material, preferably sponge rubber, attached around the edge of the shield for contact with the face of the L. wearer. The mask is held against the face by imately three pounds per square inch, to a soft,

rubber tubing IT that connects with a nipple 18 at the bottom of the mask.

The interior of the mask is in communication with the surrounding atmosphere through an air 'port 20 (Fig. 2.) that opens through the side of the mask and is controlled by a valve comprising a thin, light-weight disk 2|. This valve is of the flap type, being secured to the mask at one side by a screw 22 and the valve disk is lightly loaded by a very delicate valve spring 23. The

disk 2| may be made of a thin lamination of mica.

At sea level, the valve disk 2! is held away from its seating surface 25 by means of a valve lever 26. The upper end of the valve lever 26 is connected to the mask by a pivot 21 that serves as the fulcrum of the lever 26. An aneroid bellows 29 is secured in a fixed position in the mask and is connected to the valve lever 26 by a pivot 30. The parts are so proportioned and the stiffness of the bellows 29 so selected that with decreasing pressure surrounding the bellows, that is, with increasing altitude, the bellows will expand gradually and lift the lever 26 so that the separation between the'valve disk 2| and its seating surface 25 is gradually decreased. In practice the operation is such that the air port 20 is com- 1 pletely closed by the valve disk 2| when an altitude of 33,000 ft. is reached.

The air port 24 is used both as an' admission I port and as an, exhaust port. During expiraand opens the valve regardless of the position of the lever 26. It will be understood, however, that a separate exhaust valve controlling an exhaust portcan be provided if desired. The mask is simplified, however, by using the same port and valve both for exhaust and for the admission of air to dilute the oxygen.-

The mask includes pressure-regulator apparatus' forcontrolling the supply of oxygen into the mask. A regulating spring 33 presses against a bearing disk 34, which maybe made of paper and secured to the front of a. diaphragm .35. The edge of the diaphragm 36 isclampcd between the metal shield II and a front cover that is fastened to the shield by screws 31. There are openings 38 in the cover 36 for exposing the front rounding atmosphere.

diaphragm 35, Hence, any inward thrust upon the diaphragm 35 and the head 42 of theregulating lever 40 results in a downward thrust of a toe 44 of the lever 40. This downward thrust is communicated to a valve 46 through a thrust pin 41 which slides freely in a drilling in a wall The valve 46 controls passage of gas through a port 50. The thrust pin 41 is in axial alinement Y the valve 46 when the diaphragm 35 moves and the valve 46 is forced upward by the pressure of the gas beneath it.

The valve 46 has a face that is fiat and smooth,

and is preferably made of material that requires very little compression to effect a gas-tight closure. Soft rubber is suitable if of a grade that is'sufficiently flat and smooth, though metal can be used. The-lip against which the valve 46 seats is metal.

When the apparatus is not in useand there is no gas pressure under the valve 46, the spring 33, acting through the lever and thrust pin 4I, pushes the valve 46 as wide open as possible, but

pressure above the valve 46 gradually increases imity of the wall 54 to the periphery of the valve 4 46 insures that with increasing rates of discharge th pressure drop from the region upstream from the valve 46 to the region immediately down-- stream from the restriction is great enough to compensate for the increased counter-reaction of the pressure against the top surface of the valve 46. This feature of the invention is not limited to aviation masks, or even tobreathing apparatus.

The regulating spring 33 is preferably made sufficiently weak so that oxygen flows into the mask when the pressure in the mask is slightly less thanthe atmospheric pressure, for example at a pressure about .05 of an inch of water below the pressure of the surrounding atmosphere. As long as the pressure within the mask is above that level, no oxygen will be discharged to the mask. Hence, as long as air can be inspired through the clearance between the fiap valve 2| and its seat .25 without creating a pressure differential greater than .05 of an inch of water, no oxygen is supplied to the mask. If, however, the aneroid 29 has caused the valve 2! to close sufiiciently, there are periods in each respiratory cycle when more or less oxygen flows into.

the mask through the port 50.

,"Ihe mask can be used with a rebreathing bag if the spring 23 is made still enough to cause a I A regulating valve lever 40 is connected to the pressure rise upon expiration sufiicient to inflate the bag. The connection for the rebreathing bag can communicate with the interior of the mask through a side wall or any other port where an opening of sufilcient size can be provided.

A bafile 58 (Fig. 1) is provided to protect the diaphragm 35 and the regulator mechanism.

Changes and modifications can be made in the various elements and combinations described without departing from the invention as defined in the claims.

I claim:

1. Aviation breathing apparatus including in combination a face mask with'an inlet opening and an exhaust opening, an oxygen supply line communicating with the inlet opening, a pressure regulator comprising a valve at the inlet opening and valve-operating means responsive to the difference between the pressure within the mask and the pressure of the surrounding atmosphere, said valve-operating means being sensitive to a pressure difierential not substantially greater than one-tenth of an inch of water, an exhaust valve over the exhaust opening, an aneroid device for holding the exhaust valve open commanding the inlet port, and opening against Y the pressure of the oxygen supply, said port havmask and between the diaphragm and the thrust at low altitudes, and a light loading spring urging the exhaust valve closed, said springbeing of such a nature that it yields to permit the exhaust valve to open in response to an excess of pressure within the mask.

2. In a breathing apparatus for aviation, a mask, a pressure regulator for controlling the supply of oxygen to the mask, an exhaust valve for the mask, and aneroid control means for the exhaust valve.

3. The combination with an inhaler for an aviator, of a pressure regulator for controlling the supply of oxygen to the inhaler, said regulator including means responsive to a cessation of inspiration by the aviator for shutting oil the device-for holding the exhaust valve at least partially open at low altitudes.

motion-transmitting connections within the mask and supported from the wall of the mask for operating said valve, an exhaust valve commanding the other of the smaller openings and constructed and arranged to open outwardly for the exhaust of gas from within the mask, a diaphragm closing the large opening in the wall of the mask and exposed on one side to the outside oxygen supply, an exhaust valve, and an aneroid pin for opening the valve when the pressure outside the mask exceeds that within the mask, a light regulating spring on the atmosphere side of the diaphragm, means for the escape of gas from the mask including an exhaust valve comprising a light, thin flap valve supported on the mask and opened by aslight excess of pressure in the mask, and a delicate spring urging the exhaust valv closed. I V

6. Aviation breathing apparatus including in combination a regulator that receives oxygen at high pressure and delivers the oxygen at a reduced pressure, a flexible tubing, a face mask connected to the pressure regulator by said flexible tubing, a second pressure regulator within the mask for admitting oxygen from the tubing into the mask only when the pressure within the mask is below a predetermined relation to the pressure of the surrounding atmosphere, an exhaust .valve for the escape of excess pressure from the mask, and means responsive to changes in atmospheric pressure for holding said exhaust valve open various amounts in accordance with changes in altitude.

7. Breathing apparatus comprising a face mask having an inlet port and an exhaust port, a valve thatcommands the inlet port and opens against the pressure of the'incoming oxygen, a diaphragm that forms a part of the side of the mask, a spring urging the diaphragm to flex inward, motion-transmitting connections within the mask between the diaphragm and the inlet 40 valve for opening the inlet valve as the diaphragm flexes inwardly, and another valve commanding the exhaust port and movable independently of the inlet valve. 4

8. An aviation breathing mask having an oxygen port, an air port, and a. large opening closedv I by a bellied diaphragm, a light spring urging the atmosphere, saiddiaphragm being secured to Y the mask around theentir'e edge of said large opening so that when the mask is worn, the diaphragm, mask wall, and face of the wearer form a reduced-pressure chamber of a pressure regulator, an operative connection between the diaphragm and said motion-transmitting connections withinthe mask, means forconnecting an oxygen supply line to the mask in position to communicate with said chamber through the first of said smaller openings, and means responsive to changes in atmospheric pressure formechanically opening said exhaust valve various amounts in accordance with changes multitude.

diaphragm to flex inwardly, a valve at the inlet port, a valve stem for thrusting the valve against the pressure of the incoming gas to open said valve, a light bell-crank in the mask between the diaphragm and valve stem for displacing the valve stem when the diaphragm flexes inwardly,

another valve commanding the air port, and an aneroid control device on the mask for controlling the opening of the air port valve'in response to changes in altitude;

' 9. The method of supplying oxygen to. a breathing mask, which method comprises supplying oxygen to the mask when the pressure within the mask is slightly less than the pressure 01 the surrounding atmosphere :and only when the pressure is less than that of the surroimding atmosphere, establishing, independently of the oxygen supply, communication between the interiorot the maskand the surrounding atmos- .phere whenever the pressure'in the mask ex- 5. Aviation breathing apparatus comprising a mask, means for supplying oxygen to the mask including an inlet port through which oxygen flows into the mask, a flexible diaphragm-tormneeds that of the surrounding atmosphere, and maintaining said communication between the interior of the mask and the surrounding atmo's-i phere during inspiration to dilute the oxygen rwithin' the mask, and obstructing said communiinga part of one side of the maskexposed on the inside to the pressure inthe mask and on the outside to the pressure of the surrounding atmosphere, a valve supported by the mask cation by'varlous amounts to control the com tration'or the oxygen in the mask. v v

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