US3077881A - High altitude suit and mask oxygen regulator - Google Patents

Description

Feb. 19, 1963 w. I. SPRAGUE 3,077,881

HIGH ALTITUDE sun AND MASK OXYGEN REGULATOR Filed April 1, 1957 INVENTOR.

BY WESLEY l. SPRAGUE M 0. M

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rl/ll/l/rll/l/l/ I f i Z J i .lllllldrlllll /l w ATTORNEY all" I 3,077,831 Patented Feb. 19, 1953 3,077,881 HHGH ALTETUDE SUIT AND MASK ()XYGEN REGULATOR Wesley I. prague, Davenport, Iowa, assignor to The Bendix Corporation, a corporation of Delaware Filed Apr. 1, 19%7, Ser. No. 64?,675 6 Claims. (Cl. 12S-144) This invention relates to gas flow regulating apparatus and more particularly to aviators oxygen breathing supply and infiatable pressure suit regulators.

In very high flying aircraft in which the cabin is not pressurized, or when there is danger of decompression of the cabin, aviators must wear pressure suits, and breathing oxygen must be supplied under pressure. Pressure suits are inflated with gas, advantageously the gas that is breathed, and both the suit gas pressure and breathing oxygen pressure must increase with decrease in ambient atmospheric pressure if flights are to extend to great heights. The provision of a regulator which will automatically control both the suit pressure and the breathing oxygen pressure is one of the objects of the invention.

In most aircraft the amount of space and load capacity that can be devoted to carrying breathing and suit gas is limited. If the duration of flight is not to be limited by this factor, the gas must be conserved as much as possible. Gas conservation is another object of the invention, one object in this connection being the provision of a novel regulator in which oxygen used to inflate the suit is directed to the breathing system during deflation of the suit.

The required suit and breathing oxygen pressures, while normally diderent, are both functions of ambient atmospheric pressure or altitude. Accordingly, the suit and breathing oxygen pressures are related; and another object of the invention is to regulate these pressures in the required pressure ratio relationship.

Neither suit pressurization nor the furnishing of breathing oxygen under pressure are required at low altitudes. In most instances the aviators physiological needs are satisfied if the percentage of breathing oxygen supplied to him increases from that contained in air at sea level to one hundred percent oxygen at about thirty thousand feet. Below approximately forty thousand feet, breathing gas may be supplied to him in response to his inhalation.

Above this altiti-de oxygen must be supplied to him under pressure. When this is done his breathing is inverted in the sense that his eiiort is required for exhalation rather than inhalation. Above some higher altitude the suit must be inflated. Inflated suits are usually uncomfortable, so that it is desirable not to cause inflation at a lower altitude than necessary. it is also desirable that the suit remain inflated until a substantially lower altitude is reached to avoid successive complete deflation and reinfiation when flight altitude varies about the minimum altitude at which inflation is required.

A further object of the invention is to provide a novel regulator which will operate to supply breathing oxygen and control suit inflation in the manner described.

Certain of these and various other objects and advantages of the invention are realized by the provision of an improved breathing supply regulating arrangement and a suit inflation regulating arrangement, and novel means for integration of these regulating arrangements.

The accompanying drawing illustrates schematically one embodiment of the invention, it being understood that other embodiments are possible. Although shown schematically to indicate that the valves, pressure responsive devices, passages and other elements shown may take a variety of forms, the particular forms illustrated may advantgeously be employed. For simplicity and clarity a schematic showing of a preferred embodiment of the invention has been selected, in which the large cross-hatched areas represent a section through the body 10 of a regulator, within which various mechanisms are shown schematically or in central cross-section. The area outside of the regulator body 1%, represents the atmosphere.

Means are provided for reducing the pressure of oxygen entering the regulator to a constant value. In this embodiment, pressure regulation is accomplished by a spring and bellows operated pressure reducing valve 11. Oxygen entering inlet passage 16 flows through a filter 17 and past valve 11 to bellows chamber 14. The bellows 12. is sensitive to the pressure in chamber 14 and with spring 13 regulates valve 11 in known manner to keep this pressure constant.

Provision is made for supplying oxygen from bellows chamber 14 to the mask in response to inhalation demand at low altitudes and under pressure in accordance with ambient atmospheric pressure at high altitudes.

Two valves in the oxygen flow path and two valve actuators are employed for this purpose. One actuator opens a first one of the valves in response to inhalation demand and closes both valves when mask outlet pressure becomes excessive during exhalation. The other actuator is responsive to ambient atmospheric pressure and opens both valves to an appropriate extent when breathing oxygen is to be supplied under pressure.

In the schematic drawing this structural arrangement is represented as follows: The valves are represented by valves 18 and 50 which are shown as disposed in separate flow paths, designated as primary and secondary paths, for the supply of oxygen in response to inhalation demand and under pressure, respectively.

The primary or demand flow path extends from chamber 14, past normally closed demand valve 18, through passage 25, nozzle assembly 25 and aspirator tube 27 to mask outlet passage 2%. In addition, a system is provided for diluting with air the oxygen flowing in the primary flow path. This system is represented schematically by a diluter valve 66 connected to the ambient air, controlled by an aneroid 67 and connected to a dilution air passage 69. Ti e aneroid expands as altitude increases, gradually decreasing the air supply until the diluter valve is fully closed at the altitude above which dilution is not desired. The diluter valve may be closed at any altitude by a manually operated cam 68. When the diluter valve is open, oxygen flow from nozzle assembly 26 creates a suction in dilution air passage 69 which draws air through the diluter valve and passage 69 into the p-rimmy oxygen flow stream. A preferred form of the nozzle assembly 26 measures back pressure at the nozzle and utilizes this pressure to adjust a second valve in the dilution air path. A suitable nozzle assembly is described in application Ser. No. 490,014 filed February 23, 1955 by Wesley I. Spnague and assigned to the assignee of this invention.

A passage 29 connects the mask outlet passage 28 with a demand chamber 36. A demand diaphragm 34 extends across the demand chamber and is subjected to the pressure in this chamber 30 on one side and to atmospheric pressure in balancing chamber 35 on its other side.

The demand valve 18 is normally closed by gas pressure in chamber 14 and a bias spring 15. It is opened against this pressure by movement of diaphragm 34 through suitable mechanism. As shown, a hub 36 attached to the center of diaphragm 34 carries the free end of a lever 37 which is pivoted at its other end at 33. Upon movement of the diaphragm 34 to rotate lever 37 clockwise, the latter actuates a second lever 39 pivoted at 4%. Lever 39 is connected to the demand valve 18, and upon actuation by lever 37 opens said demand valve.

Demand for gas at the mask during inhalation creates a suction in passages 28 and 29 and in demand chamber 39, resulting in movement of diaphragm 34 and levers 37 and39 to open demand valve 18. Gas then flows through the primary flow path from chamber 14 to mask outlet 28. The aspirator tube 27 in this circuit creates additional suction via passage 29 in chamber 30 in a cordance with flow rate through said tube. When inhalation demands a high rate of oxygen flow, this suction effect results in further opening of valve 13 to satisfy the demand.

The secondary or pressure mask supply path extends from bellows chamber 14 past suit and mask pressure valve 46, through suit and mask pressure chamber 47 and valve 50 to the demand chamber 30. Chamber 47 is closed by suit pressure diaphragm 55 and mask pressure diaphragm 56 which are attached to the heads of valves 46 and 50, respectively.

The operation of valve 46 will be described later in greater detail. It is sufficient at this point to understand that it regulates the flow of oxygen from bellows chamber 14 to mask and suit pressure chamber 47, so that the pressure of the oxygen in the latter chamber increases as ambient atmospheric pressure decreases or altitude increases. Mask pressure diaphragm 56 is exposed to this pressure at one side and to atmospheric pressure in chamber 35 at its other side.

The lower end 60 of valve body 59 is the head of valve 50. The valve body 59 extends from chamber 47 through a central opening in diaphragm 56 and through hub 36 into demand chamber 30, where its upper end is engageable with lever 39. The valve body 59 is secured to diaphragm 56 by fastening members 62. It is slidable in hub 36 and is hollow.

At the altitude at which oxygen is required to be supplied under pressure to the mask, the increased pressure in chamber 47 and the reduced pressure in chamber 35 will cause diaphragm 56 to lift valve body 59 to lift head 60 of valve 50 from its seat 61. By the same movement the other end of the valve body 59 is brought into engagement with lever 39. Gas from pressure chamber 47 will flow through valve head 60 and body 59 into demand chamber 30 and thence through passages 29 and 28 to the mask. Lever 39, actuated by movement of body 59, opens demand valve 18. This allows additional oxygen flow to the mask through the primary flow path.

Gas pressure at mask outlet 28 is transmitted through passage 29 and chamber 30 to demand diaphragm 34. The latter is moved so that its hub 36 slides over valve body 59 toward engagement with fastening members 62. This movement of the hub 36 carries lever 37 away from engagement with lever 39. As mask outlet pressure increases, diaphragm 34 will move hub 36 into engagement with fasteners 62 and will force diaphragm 56 in a direction to carry valve head 60 toward engagement with its seat 61 and out of engagement with lever 39. Actuating lever 39 being released, demand valve 18 will be closed by bias spring 15 and the pressure in chamber 14.

In connection with the mask supply system, a safety valve 65 may be provided which will open to relieve pressure in mask outlet 28 if the pressure there becomes excessively high.

The invention provides means for inflating the suit at high altitudes as altitude is increased, and deflating it as altitude is decreased. Inflation and deflation are automatically controlled so that the degree of inflation, that is, the gas pressure in the suit, has a predetermined relationto ambient atmospheric pressure. Means are provided for varying the pressure of the suit supply oxygen with altitude so that this oxygen is maintained at the required suit pressure. Suit inflating and deflating valve means are provided for sensing any difference between the suit supply oxygen pressure and the pressure of oxygen in the suit and permitting inflation and deflation of the suit in accordance with pressure difference. The suit inflation and deflation valve means and the means for limiting suit inflation to high altitudes may be combined in a single valve.

In the form illustrated, the suit supply path extends from bellows chamber 14, past suit and mask pressure valve 46 to mask and suit pressure chamber 47, thence past suit valve 75} to suit connection 71. The suit valve comprises a seat 79 and a head 80, the latter being carried by a diaphragm 81. The diaphragm 81 has one side exposed to mask and suit pressure chamber 47 and its other side exposed to the atmosphere. A spring 83 biases the valve head 86 toward closure.

It has been explained that oxygen pressure in the mask and suit pressure chamber 47 increases and decreases with altitude at altitudes where positive mask supply pressure is required. This pressure is sufiicient, at some altitude lower than that at which suit inflation is required, to close a normally open, diaphragm operated suit vent valve 75. In the form selected for illustration this valve comprises a diaphragm 76 which acts as a valve head and a spring 78 which normally holds the diaphragm away from the valve seat 79. Pressure in chamber 47 is applied to diaphragm 76 through a passage 77, at lower altitudes valve is opened by spring 78 and suit pressure and the suit is entirely deflated.

When the pressure in chamber 47 increases to a selected value, diaphragm 81 moves to carry head 80 away from seat 79. Oxygen flows fromchamber 47 through the valve 70 and passage 71 to inflate the suit. Pressures of theoxygen inthe suit and in chamber 47, acting on valve head 80 and diaphragm 81, combine to hold diaphragm 81 in the valveopen position. As the pressure in chamber 47 and the ambient pressure vary with altitude, oxygen flows into or out of the suit as required to equalize pressure in the suit and chamber.

In the embodiment of the invention selected for illustration, the suit valve and the mask pressure valve are connected to a common chamber represented by mask and suit pressure chamber 47. It has been brought out in the description of the pressure breathing and suit infia tion systems, that the pressure in this chamber varied with altitude at altitudes at which pressure breathing is required. At these altitudes mask pressure valve 50 is open and oxygen flows from chamber 47 through this valve. Therefore, pressure in chamber 47 can be, and is, increased or decreased by opening mask and suit pressure valve 46 to admit gas to the chamber at a greater or lesser rate than that at which it flows out through valve 50.

The mask and suit pressure valve 46 comprises a seat 85 and a head 86. The head is moved by movement of the diaphragm '55 to which it is connected. The diaphragm has-one face exposed to mask and suit pressure chamber 47. Its other face is exposed to the ambient atmosphere in an aneroid chamber 87. A pressure control aneroid 88 in this chamber expands and contracts as altitude is increased and decreased, respectively, and is coupled to the diaphragm 55 so that the latter tends to open valve 46 when the aneroid expands.

In the form shown, the coupling is accomplished through a lever disposed in the aneroid chamber 87 and pivoted at 91. At one side of the pivot the lever is connected through a take-up spring 92 to diaphragm 55. The aneroid 88 is connected through a take-up spring 93 to the lever 90 at the other side of the pivot 91.

Aneroid 88 is preferably constructed so that it does not begin expanding until that altitude is reached at which oxygen is required to be supplied to the mask outlet under pressure. Above this altitude aneroid 88 expands to compress spring 93. The restorative force in the spring is applied through lever 90 and spring 92 to valve 46 which opens to admit oxygen and increase the pressure in chamber 47. Expansion of the aneroid and consequent further compression of spring 93 and increase in chamber 47 pressure, continues until the altitude is reached at which the suit is to be inflated. At substantially this altitude, an anvil carried by the aneroid engages a follower screw 101 fixed to lever 90 thereupon the full expansive force of the aneroid is applied through lever 99 to spring 92 and the latter is compressed until exten- 'sion 102 of lever 90 engages valve stem 103 of valve 46. As altitude is increased further the expansive force of the aneroid continues to increase but expansion, being opposed by pressure in chamber 47, will vary in accordance with relative changes in chamber 47 pressure and atmospheric pressure.

Thus the take-up springs 93 and 92 permit flexible control of valve 46 operation at intermediate altitudes in accordance with need for oxygen at the mask. At higher altitudes where mask pressure is required to be substantial and suit inflation is necessary, the springs are overcome and aneroid exercises more positive control over operation of valve 46. Thus the pressure in chamber 47 is maintained at a value which is a selected inverse function of ambient atmospheric pressure. If for any reason 'the pressure in chamber 47 becomes excessive, safety valve 96 opens the chamber to theatmosphere to relieve this'pressure.

Required suit pressure and required mask pressure are both functions of ambient. atmospheric pressure and so are related to one' 'another. This relationship may be expressed as the ratioo'f required suit pressure to required mask pressure; and the ratio may be considered to be constant over-the altitude range at which both suit and mask pressure are required. The pressure in mask and suit pressure chamber 47 is equal to the required suit pressure and is the pressure applied to diaphragm 56 to open mask pressure valve 50. Since this valve may be closed by demand diaphragm 34, and since the latter is sensitive to mask pressure, the mask pressure may be limited to the valve bearing the required ratio to suit pressure by construction of the diaphragm 34 and 56 so that their respective effective areas have the inverse of this ratio. For example, if mask pressure is to be one-fifth of suit pressure, the efiective area of demand diaphragm 34 is made five times as large as that of pressure diaphragm 56. If mask pressure becomes more than onefifth of suit pressure the demand diaphragm 34 will close valve Si} by the engagement of hub 36 with members 62; if mask pressure is less than one-fifth of suit pressure the pressure diaphragm 56 will open valve 56 and the primary demand valve 18.

t is desirable to provide means for opening mask and suit valve 4% manually for testing the suit and pressure supply to the mask and to deliver oxygen to the mask under pressure at low altitudes if desired. Such means are represented schematically by a cam 93. The cam engages an extension of lever 99 and is manually rotatable about a pivot 99 to actuate the lever and open valve 46.

Summarizing operation of the regulator, the pressure of oxygen entering at inlet 16 is reduced at valve 11 so that a constant pressure is maintained in bellow chamber 14. A demand valve 18, operated by demand diaphragm 34' in response to inhalation demand, opens to connect the chamber 14 to the mask outlet passage 24%. An aneroid operated diluter valve 66, unless manually closed, admits air to this flow path in decreasing quantity as altitude increases. Above a given altitude the diluter valve remains closed.

When the altitude is reached above which oxygen is required to be supplied to the mask under pressure, pressure control aneroid 88 opens mask and suit pressure valve 46, permitting oxygen flow from bellows chamber 14- to mask and suit pressure chamber 47. Pressure in the latter chamber is maintained at a value variable with altitude and acts to open a mask pressure valve 50 and the demand valve 18 at appropriate pressure. If mask pressure becomes excessive, the demand diaphragm 34 closes both of the valves 18 and 50.

At some higher altitude the pressure in chamber 47, closes vent valve 75, opens the suit valve 70, and the suit is inflated by oxygen flowing through this valve 5 from chamber 47. Thereafter, when altitude is decreased, aneroid 88 contracts to permit decrease in the opening of mask and suit pressure valve 46. Thus pressure in chamber 47 and in the suit is decreased as oxygen flows to the mask through pressure valve 5% from the suit and chamber 47 and from the mask.

At altitudes where the suit is pressurized, the ratio of suit and mask pressures is held constant by diaphragms 34 and 56, whose areas have the inverse of the required pressure ratio. Diaphragm 56 opens and diaphragm 34 closes the valve 50 through which oxygen flows from the mask and suit pressure chamber to the mask.

In connection with this description it is to be understood that although the elements illustrated may advantageously be employed, they are schematic representations of apparatus which will perform a required function and other apparatus having a corresponding function may be employed. In addition, other embodiments of v the invention than the one illustrated may be made without departing from the spirit of the invention or the scope of the appended claims.

The term mask, as it is used herein, is intended to describe various forms of apparatus for administering oxygen to the user, including enclosed helmets.

I claim:

1. Flow regulating apparatus for supplying oxygen in response to inhalation demand at low altitudes and under pressure at high altitudes comprising means including first and second passages connected in parallel, first and second control valves in said first and second passages respectively, means for regulating inlet pressure in the second passage at the inlet side of said second valve in accordance with the inverse of ambient atmospheric pressure, means responsive to said inlet pressure for opening both of said valves, and means responsive to outlet pressure at the outlet side of said valves for opening only said first valve in response to inhalation demand and closing both of said valves at outlet pressures exceeding a predetermined fraction of the inlet pressure in the second passage.

2. In a pressure suit and mask oxygen flow and pressure regulator, a housing defining a suit connector opening and a mask connector opening, a liowpath defined by said housing and extending between said openings, first and second normally closed flow control valves in said flowpath the first valve being disposed between the second valve and said mask connector opening and the second valve being disposed between the first valve and the suit connector opening, .eans responsive to ambient atmospheric pressure for introducing oxygen into said flowpath intermediate said first and second valves at a pressure inversely variable with ambient atmospheric pressure, pressure responsive means for opening said second valve when the combined pressures in said flowpath on opposite sides of said second valve exceed ambient pressure by a preselected amount, and pressure responsive means for opening said first valve when the pressure in said flowpath intermediate said valves exceeds ambient atmospheric pressure by a second preselected amount only if the pressure in said flowpath intermediate said first valve and said mask connector opening exceeds ambient atmospheric pressure by less than a third preselected amount.

3. Flow regulating apparatus for supplying oxygen to a mask in response to inhalation demand at low altitudes and under pressure at high altitudes, comprising a housing, a fiowpath defined by said housing terminating in a mask supply opening, a first mask su-pply valve in said flowpath, a demand diaphragm, a demand chamber defined by said demand diaphragm and said housing and communicating with said flow path intermediate said valve and said mask supply opening, means including said demand diaphragm for opening said first mask supply valve in response to inhalation suction applied to said demand chamber, a pressure diaphragm, a pressure chamber defined by said pressure diaphragm and said housing, said demand diaphragm having an opening, a member carried by said pressure diaphragm and slidably disposed in the opening of the demand diaphragm and having a passage connecting said chambers, means for supplying oxygen to said pressure chamber and for regulating the pressure of oxygen therein in accordance with altitude, a second mask supply valve for controlling flow of oxygen through said passage, and means including said element responsive to pressure in said pressure chamber for opening said second supply valve and responsive to pressure in said demand chamber for closing said second supply valve.

4. The invention defined in claim 3 including means operated by movement of said member for opening said first mask supply valve in response to increased pressure in said pressure chamber.

5. The invention defined in claim 3 in which said means for closing said passage in response to pressure applied to said demand diaphragmcomprises means for transmitting motion of said demand diaphragm in response to said pressure to said pressure diaphragm in ardirectionvtendiug to close said second mask supply valve.

6. Oxygen flow regulating apparatus wherein oxygen is to be supplied to a mask outlet in accordance with inhalation demand at low altitudes and under a predetermined pressure at high altitudes, comprising dual passage means arranged in parallel for supplying oxygen'from a pressurized source to said outlet, means comprising a pair of valves one connected in each of said passage means for controlling flow of oxygen through said passage means,

means responsive to pressure at the outlet side of said valves for opening one of the valves in response to inhalation demand and for closing both of the valves at outlet pressures above a selected value, and means responsive to ambient atmospheric pressure 'for opening both of said valves at outlet pressures exceeding by less than a predetermined amount the ambient atmospheric pressure corresponding to a selected high altitude, said means for opening both of said valves comprising a first diaphragm having actuating connection to said valves and means for subjecting said diaphragm to the difference between ambient atmospheric pressure and a pressure inversely variable with atmospheric pressure in a direction to open said valves, and said means for opening one of the valves and closing both of said valves comprising a second diaphragm subjected to the diiference between ambient atmospheric pressure and the pressure at said outlet and means for opening said one valve in response to diaphragm movement incident to decrease in said outlet pressure and for closing both valves in response to diaphragm movement inthe opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS 2,390,233 Aker-man'et a1. Dec. 4, 1945 2,703,572 Seeler Mar. 8, 1955 2,757,680 Fay Aug. 7, 1956 2,834,343 Keckler May 13, 1958 2,867,227 Meidenbauer, Jan. 6, 1959

Claims (1)

1. FLOW REGULATING APPARATUS FOR SUPPLYING OXYGEN IN RESPONSE TO INHALATION DEMAND AT LOW ALTITUDES AND UNDER PRESSURE AT HIGH ALTITUDES COMPRISING MEANS INCLUDING FIRST AND SECOND PASSAGES CONNECTED IN PARALLEL, FIRST AND SECOND CONTROL VALVES IN SAID FIRST AND SECOND PASSAGES RESPECTIVELY, MEANS FOR REGULATING INLET PRESSURE IN THE SECOND PASSAGE AT THE INLET SIDE OF SAID SECOND VALVE IN ACCORDANCE WITH THE INVERSE OF AMBIENT ATMOSPHERIC PRESSURE, MEANS RESPONSIVE TO SAID INLET PRESSURE FOR OPENING BOTH OF SAID VALVES, AND MEANS RESPONSIVE TO OUTLET PRESSURE AT THE OUTLET SIDE OF SAID VALVES FOR OPENING ONLY SAID FIRST VALVE IN RESPONSE TO INHALATION DEMAND AND CLOSING BOTH OF SAID VALVES AT OUTLET PRESSURES EXCEEDING A PREDETERMINED FRACTION OF THE INLET PRESSURE IN THE SECOND PASSAGE.

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