Breathing apparatus

June 13, 1961

2,988,085

L. JONES

BREATHING APPARATUS

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ATTORNEY

June 13, 1961

Filed June 17, 1957

L. JONES

BREATHING APPARATUS

2,988,085

Sheets-Sheet :2

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ATTORNEY

United States Patent Office

2,988,085

Patented June 13, 1961

2,988,085

BREATHING APPARATUS

Leon Jones, Garden Grove, Calif., assignor to Robertshaw-Fulton Controls Company, Richmond, Va., a corporation of Delaware

Filed June 17,1957, Ser. No. 665,955

Claims. (CI. 128—142)

This invention relates to breathing apparatus and more particularly to breathing apparatus for use in high altitude flight.

For high altitude flying where the atmospheric air is rarefied, it is desired to normally maintain a predetermined partial pressure of oxygen within the face mask, or helmet to meet physiological requirements of the human body. It is, therefore, a principal object of this invention to incorporate in a breathing regulator a means which automatically varies the pressure within the mask or helmet with variations in altitude.

Another object of the invention is to subject the control diaphragm of a demand breathing regulator to the pressure of the oxygen source and to control the oxygen pressure on the control diaphragm in accordance with altitude.

Another object of the invention is produce an improved breathing regulator.

In the preferred embodiment of the invention, a demand regulator valve is connected between a suitable mask or helmet associated with the user of the apparatus and a source of oxygen under pressure. The regulator valve is operative to supply oxygen to the mask or helmet in response to inhalation by the user, and is provided with a means responsive to atmospheric pressure for maintaining a predetermined pressure of oxygen within the mask or helmet at low atmospheric pressure conditions such as when flying at high altitudes.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a schematic illustration of a breathing apparatus;

FIG. 2 is a plan view of a regulator valve embodying this invention;

FIG. 3 is a section taken along the line ΙΠ—III of FIG. 2;

FIG. 4 is a section taken along the line IV—TV of FIG. 2; and

FIG. 5 is a sectional view showing a modification of a portion of the structure illustrated in FIG. 3.

Referring more particularly to FIG. 1, the breathing apparatus includes a pressure reducing valve 10 connected to a suitable source of oxygen under pressure (not shown) by a conduit 12. The reducing valve 10 may be of any suitable form and serves to deliver oxygen at a workable pressure to a breathing regulator 14 by means of a conduit 16. The regulator 14 is here shown as mounted on a face mask 18.

Referring more particularly to FIGS. 2, 3, and 4, the regulator valve 14 comprises a casing 20 having a hollow tubular inlet fitting 22 extending upwardly from one side thereof. The casing 20 is also provided with an externally threaded lower portion 24, on which hollow tubular outlet fitting 26 is threaded. The inlet fitting 22 is adapted for connection to the conduit 16 (FIG. 1), and the outlet fitting 26 is adapted for connection to the mask or helmet 18.

The inlet fitting 22 has a suitable filter 28 mounted therein, and is connected by means of a passage 30 to a valve chamber 32 formed within the casing 20. The valve chamber 32 communicates with the outlet fitting 26 by means of a plurality of ports 34 which communicate with an opening 36 in the bottom wall of the casing portion 24.

An annular valve seat 38 is formed on the casing 20 within the valve chamber 32 for cooperation with a flex5 ible diaphragm valve member 40 for controlling fluid flow from the inlet passage 30 to the ports 34. The valve member 40 is secured at its periphery to the wall of the casing 20 by means of an annular retaining member 42.

A passage 44 extends through the casing 20 from the 10 inlet passage 30 and opens into the valve chamber 32 on the lower side of the diaphragm valve member 40 to subject the lower side of the diaphragm valve member 40 to the inlet fluid pressure. The passage 44 is provided with a chamber 46 in which a fitting 48 having a meter15 ing orifice therein is positioned. With this arrangement, the upper side of the valve member 40 is subjected to the inlet fluid pressure within passage 30, and the lower side of the valve member 40 is subjected to the inlet fluid pressure by means of passage 44.

It will be apparent that the effective area of the valve member 40 exposed to inlet pressure at the lower side thereof is greater than the exposed area of the upper side. This difference in area subjected to inlet fluid pressure accordingly establishes a pressure differential on the valve 25 member 40 which normally tends to hold the same in engagement with the seat 38.

The valve member 40 is moved out of engagement with the seat 38 to permit flow of fluid to the ports 34 and outlet fitting 26 by venting the fluid pressure acting on the 30 lower side thereof to reverse the pressure differential acting on the valve member 40. To this end, a passage 50 formd in the casing 20, extends from the valve chamber 32 at the under side of the diaphragm valve member 40 and opens into a chamber 52 formed in the cas35 ing 20 which communicates with the interior of the mask or helmet 18 by means of a port 54 opening into the outlet opening 36.

A flexible diaphragm sensing element 56 is secured at its periphery to the upper end of the casing 20 to enclose 40 the chamber 52 and to define the upper wall thereof. The position of the diaphragm sensing element 56 is influenced by the fluid pressure within the chamber 52. Accordingly, since the chamber 52 is in communication with the mask or helmet 18, a reduction in pressure will 45 occur within the chamber 52 when the user of the apparatus inhales causing the diaphragm 56 to flex downward. This movement of the diaphragm 56 in response to inhalation by the user is used to control the venting of the fluid pressure acting on the under side of the valve 50 member 40 to thus control opening of the valve member 40.

A hollow fitting 58 has one end pressed within the end of the passage 50 and the other end thereof projecting within the chamber 52 to define a pilot valve seat. A 55 pilot valve, indicated generally by the reference numeral 60, is cooperative with the end of the fitting 58 to control fluid flow from the valve chamber 32 through the passage 50 to the chamber 52. The pilot valve 60 comprises a rigid lever arm 62 having one end engaging the 60 diaphragm 56 and the other end thereof fixed to a block 64 overlying the fitting 58. One end of a strip 66 of sealing material is secured to the underside of the block 64 and the other end of the strip 66 is clamped to an extending and movable partition 68 of the casing 20 by 65 means of a nut 70 tightened against the partition 68 by a screw 72 seated within the casing 20. A spring 74 has one end attached to the block 64 and the other end thereof attached to the nut 70 for biasing the block 64 downwardly and the end of the lever arm 62 into engagement 70 with the diaphragm 56. During assembly, the screw 72 is tightened to cause downward deflection of the partition 68 until the strip 66 engages the end of the fitting 58.

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The spring 74 normally biases the block ¢4 and strip 66 into engagement with the end of the fitting 58. However, should the diaphragm 56 be flexed downwardly by reduction in pressure within the chamber 52 as a result of inhalation, displacement of the lever arm 62 will occur, and the spring 74 will yield adjacent to the nut 70 against its bias and move the block 64 out of engagement with the fitting 58 to permit flow of fluid from the passage 50. When the user exhales, the pressure·in chamber 52 will increase to move the diaphragm 56 upwardly and close the pilot valve 60 to thus re-establish the pressure differential on the valve member 40 causing the same to engage its seat 38.

It has been found that chattering or vibration of the diaphragm valve member 40 sometimes occurs due to the rapid pressure change in chamber 32 upon opening and closing of the pilot valve 60. To provide for a more gradual pressure build-up or relief on the underside of the diaphragm valve member 40 during operation of the pilot valve 60, a surge chamber 76 having a metering orifice 77 is provided in the casing 20 in communication with the passage 44. It will be apparent that upon flow of fluid from the valve chamber 32 as a result of opening of the pilot valve 60, the flow of fluid from the chamber 76 as determined by the metering orifice 77 will reduce the rate of pressure drop within the chamber 32. Likewise, the rate of pressure build-up within the chamber 32 will be decreased by pressure build-up in the chamber 76 when the pilot valve 60 is closed.

When the regulator thus far described is used at high altitudes or under low atmospheric pressure conditions, it is desired to establish a predetermined pressure within the mask or helmet 18 independently of inhalation on the part of the user to provide pressure breathing. Accordingly, the regulator valve is provided with means for maintaining a predetermined pressure within the mask or helmet 18 in accordance with the surrounding atmospheric pressure. To this end, a cup-shaped member 78 having an upper inwardly extending flange 80 is clamped to the upper end of the casing 20 and to the periphery of the diaphragm 56 by means of a cover 82 threaded on the upper end of the casing 20 in engagement with a lower outwardly extending flange 81 of the member 78. The flange 80 is provided with a central bore 84 in which a cup-shaped valve member 86 is positioned. The valve member 86 is provided with an outwardly extending flange 88 terminating in an annular downwardly bent lip 90 above the flange 80.

The valve member 86, member 78 and diaphragm 56 define a chamber 92 above the diaphragm 56 which communicates with the inlet passage 30 by means of a passage 94 formed in one side of the member 78. The passage thus establishes a fluid pressure within chamber 92 which acts on the upper side of the diaphgarm 56 through a plurality of ports 95 in the bottom wall of the member 78.

The valve member 86 is cooperative wtih the flange 80 to control the fluid pressure within the chamber 92. When the valve member 86 is in the position shown in FIG. 3, the lip 90 is out of engagement with the flange 80 and fluid pressure is vented from the chamber 92 to the atmosphere through a plurality of ports 96 in the cover 82. However, if the valve member 86 is moved toward the diaphragm 56, the lip 90 will be moved closer to the flange 80 to throttle the flow of fluid from the chamber 92 and increase the fluid pressure within chamber 92.

An expansible bellows member 97 is provided for actuating the valve member 86 relative to the flange 80. The bellows member 97 has one end sealed to the bottom wall of the valve member 86 and the other end thereof sealed to a flange 98 of a cup-shaped member 100. The member 100 is provided with a central conical recess or indentation 102 which engages a flange 104 formed on one end of a screw 106 threaded through the cover 82 in axial alignment with the bellows member 97. A spring

107 is mounted in compression between the valve member 86 and flange 98 within the bellows member 97 and serves to bias the bellows member 97 and valve member 86 downward.

The bellows member 97 is evacuated and will expand in response to a decreaase in atmospheric pressure to actuate the valve member 86 downward to move the lip 90 toward the flange 80. Thus, the bellows member 97 will expand in response to an increase in altitude to move the lip 90 toward engagement with the flange 80 to increase the fluid pressure within chamber 92.

A relief valve, indicated, generally by reference numeral 108, is positioned adjacent the tubular outlet fitting 26 to vent fluid pressure from the interior of the outlet fitting 26 when the fluid pressure exceeds a predetermined value. To this end, a hollow tubular casing 110 is secured to the side of the tubular outlet fitting 26 and is provided with a plurality of ports 112 extending through the wall thereof. A valve seating ring 113 is fixed within the tubular casing 110 and is adapted to be engaged by a valve member 114 which is slidably mounted on a guide stem 116 fixed to the end wall of the casing 110. A spring 118 encircles the stem and is mounted in compression between the end wall of the casing 110 and the •valve member 114 for biasing the valve member 114 into engagement with the seating ring 113.

Fluid is conducted from the hollow interior of the fitting 26 to the underside of the valve member 114 by means of a drilled passageway 120. The passage 120 also communicates with a hollow tube 122 which may be utilized to supply oxygen to a compensated exhaust valve :(not shown) within the mask 18.

It will be apparent that a pressure differential exists across the valve member 114 when the same engages the seat therefor since one side of the valve member -114 is subjected to the oxygen pressure within the outlet fitting 26 and the other side thereof is subjected to atmospheric pressure. As long as the pressure differential force on the valve member 114 is less than the bias of the spring 118, the valve member 114 will engage the seat. If, however, due to an increase in the fluid pressure in the outlet fitting 26, the pressure differential force becomes greater than the biasing force of the spring 118, the valve member 114 will be moved out of engagement with the seat to vent the excessive fluid pressure in tube 122 to the atmosphere. This will allow the exhalation valve to relieve excess mask pressure.

In operation of the structure illustrated in FIGS. 2, 3, and 4, when the apparatus is used at low altitudes or at relatively normal atmospheric conditions, the bellows member 97 will be in a contracted condition and the valve member 86 will be in its uppermost position wherein the lip '90 is out of engagement with the flange 80. In this position of the valve member 86, fluid pressure is vented from the chamber 92 to the atmosphere, and the-fluid pressure within chamber 92 will be minimum and approximately atmospheric.

When the user of the apparatus inhales, a reduction in fluid pressure within chamber 52 will occur and the diaphragm 56 will be deflected downward under the influence of the fluid pressure within chamber 92. Such movement of the diaphragm 56 will cause opening of the pilot valve ;60 as previously described to effect opening of the valve member 40. When the valve member 40 is thus opened, oxygen will be supplied to the mask 18.

Since the chamber 52 communicates with the interior of the mask 18 by means of the port 54, exhalation on the part of the user will increase the fluid pressure within the chamber 52 to return the diaphragm 56 to its original position to close the pilot valve 60 and valve member 40.

If a decrease in atmospheric pressure should occur, such as during an increase in altitude, the bellows member^? will expand to move the valve member 86 downward. This movement of valve member 86 will accord0,808,006 g

ingly position the lip 90 closer to the flange 80 to throttle the flow of fluid from the chamber 92 causing an increase in fluid pressure within the chamber 92.

The increased fluid pressure in chamber 92 will move the diaphragm 56 downward and open the pilot valve 60 to effect opening of the valve member 40 to cause oxygen flow to the mask 18. However, since the chamber 52 is in communication with the mask, the supply of oxygen to the mask when the user is not inhaling will increase the pressure in chamber 52 causing a pressure force to be exerted on the diaphragm 56 in opposition to the fluid pressure acting on the upper side of the diaphragm 56. This build-up in pressure within chamber 52 will continue until the pressure in chamber 52 equals the pressure in chamber 92 at which point the diaphragm 56 will have returned to its original position closing the pilot valve 60 and valve member 40.

It will be apparent that in operation in the above manner, the diaphragm 56 serves as a pressure regulator to maintain a fluid pressure within the mask 18 as determined by the position of the bellows member 97. Also, since inhalation on the part of the user is effective to open the pilot valve 60 by establishing a pressure differential on the diaphragm 56, it will be apparent that the sensitivity of the device to inhalation is constant irrespective of the atmospheric pressure condition sensed by the bellows member 97. This is due to the fact that the fluid pressure in chambers 52, 92 is always substantially the same. Accordingly, when the user inhales, the same pressure difference is established across the diaphragm 56 at high atmospheric pressure conditions as is established at low atmospheric pressure conditions. Thus, the device is operative to effect pressure breathing at low atmospheric pressure conditions without effecting the sensitivity of the device to inhalation and exhalation on the part of the user.

If it is desired to calibrate the response of the bellows member 97 to a particular atmospheric pressure condition, the screw 106 may be rotated to vary the axial position of the bellows member 97 and valve member 86 relative to the flange 80. Such positioning of the bellows member 97 will accordingly vary the pressure condition at which the lip 90 engages the flange 80.

If due to any condition, the pressure within the mask 18 becomes excessive, it will be apparent that relief valve 108 will open to vent the excessive fluid pressure in tube 122 to the atmosphere and allow the exhalation valve (not shown) to vent excess mask pressure.

Referring now to FIG. 5, the tubular outlet fitting 26 is shown as provided with another embodiment of the relief valve 108. More particularly, the bellows-type expansible element 124 is mounted within the fitting 26 and has one end 126 clamped to the bottom wall of the casing 20 by means of an annular clamp 128 which is engaged by a shoulder of the fitting 26. The other end 130 of the element 124 is secured to a peripheral flange 132 of a movable spider 134 by means of a locking ring 136.

An annular valve member 138 is formed on the end -------- --— of the element 124 and is adapted to engage an annular 60 said diaphragm being movable in response to a decrease in pressure in said other chamber caused by inhalation and movable in response to a change in fluid pressure in said one chamber, an operative connection between said diaphragm and said pilot valve element for actuatA spring 144 is mounted in tension between the center 65 ing said pilot valve to open said differential pressure of the spider 134 and the center of a second spider 146 threaded within the end of the fitting 26. With this arrangement, the spring 144 serves to bias the element 124 to cause expansion of the same and engagement of the _ . „_____________ valve member 138 with the shoulder 14» to prevent 70 actuating the same to increase the pressure in said one communication between the interior of the fitting 26 and the ports 142. If, however, the fluid pressure within the interior of the fitting 26 should exceed a predetermined value, the element 124 will contract under the influence of engagement with the shoulder 140 to vent the excessive fluid pressure to the atmosphere through the ports 142.

It will be apparent that the pressure at which the valve member 138 moves out of engagement with the shoulder 140 is readily adjusted by rotating the spider 146 to vary the axial position thereof and the tension of the spring 144.

While several embodiments of the invention have been herein shown and described, it will be apparent to those skilled in the art that many changes may be made in the construction and arrangement of parts without departing from the scope of the invention as defined in the appended claims.