United States Patent 3724482

A breathing valve having a housing comprising an inlet chamber in communication with which is an inlet opening controlled by an inlet valve, a passage to the breathing organs of the user and an exhalation valve. A control diaphragm subject on one side to the pressure in the inlet chamber acts through an intermediate member to control the inlet valve. An overpressure valve on the side of the control diaphragm across from the inlet chamber receives fluid through the exhalation valve and when the pressure in the overpressure chamber builds up it causes the control diaphragm to open the inlet valve. Springs act on the two diaphragms urging them towards the inlet valve opened position, thereby setting a predetermined pressure value in the overpressure chamber. With this structure, an overpressure is created in the inlet chamber during both inhalation and exhalation.

Application Number:
Publication Date:
Filing Date:
Primary Class:
Other Classes:
137/859, 137/908
International Classes:
A62B9/02; B63C11/22; (IPC1-7): A62B7/04
Field of Search:
137/102,104,112,115,116.5,119,63R 128
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US Patent References:

Primary Examiner:
Nilson, Robert G.
Assistant Examiner:
Look, Edward
I claim

1. A breathing valve comprising: a housing having an inlet, an outlet and an opening adapted to be connected to lead to a user, an inlet chamber, an inlet valve controlling the flow of gas from the inlet to the inlet chamber, the said inlet and the said opening both being in fluid connection with the inlet chamber, a control diaphragm, one side of which is subjected to gas pressure in the inlet chamber, a control means including a lever operatively connecting said control diaphragm and the inlet valve such that movement of the control diaphragm actuates the inlet valve, an overpressure diaphragm spaced from the control diaphragm and forming with it an overpressure chamber, a first outlet valve connecting the inlet chamber and the overpressure chamber and opening in a direction toward the overpressure chamber, means including a stud connected with the central part of the overpressure diaphragm and extending against the control diaphragm, a control spring acting on the overpressure diaphragm holding said stud against the control diaphragm in a direction tending to operate the lever to open the inlet valve, a second outlet valve connecting the overpressure chamber and the surrounding atmosphere, a second spring for loading said second outlet valve, and an adjustable member in the housing, both said springs resting against said adjustable member, wherein adjustment of the adjustable member varies the force exerted by the springs on the overpressure diaphragm and hence varies the overpressure in the overpressure chamber.

2. A breathing valve according to claim 1, wherein the adjustable member comprises a lid having openings therein.

3. A breathing valve according to claim 1, wherein the circumference of the overpressure diaphragm forms a movable element of said second outlet valve, said second spring loading said circumference of the overpressure diaphragm.

4. A breathing valve according to claim 1, wherein the control diaphragm includes openings which are closed by the said first outlet valve. AGA Aktiebolag 03 Lidingo SW

This invention relates to breathing valves, and in particular, it relates to a breathing valve of the type in which a control diaphragm is adapted to actuate the inlet valve.

In order to obviate leakage into a breathing mask during breathing in an extremely noxious atmosphere, it is desirable that a small overpressure, so called safety-pressure, is upheld in the breathing mask during inhalation. In conventional devices with a breathing valve of the demand-type an underpressure is produced inside a control diaphragm or a piston during the inhalation. The difference in pressure on the both sides of the diaphragm provides a force which actuates a valve mechanism so that a flow of gas is supplied to the user of the apparatus. Normally a breathing mask is used, to which the breathing valve is connected. If the breathing mask or the breathing valve do not tighten sufficiently, for instance if the user wears a beard, there is a risk that noxious gas may leak in during the inhalation phase when an underpressure prevails inside the breathing mask and the valve. This face is commonly known and different solutions have been presented for producing an overpressure.

When the apparatus is used for diving under water, an overpressure is not necessary and, in fact, is undesirable. If the same equipment is to be usable both for diving under water and for breathing in a noxious atmosphere, the overpressure should be removable.

In previous valve arrangements switching between overpressure and non-overpressure has required complex and time-consuming adjustments of valve pressures. If one of these adjustments is forgotten the diver would risk a dousing of the breathing gas.

Thus, there exists a need for a new and improved breathing valve in which an overpressure is created during both inhalation and exhalation and in which the overpressure producing means may be removed simply and easily so that the breathing valve can be readily converted for use either in an environment of noxious gas or under water.


It is a purpose of this invention to provide a new and improved breathing valve which overcomes the above described disadvantages of the prior art.

According to the present invention, a breathing valve suitable for breathing in an extremely noxious atmosphere is obtained by providing the valve with overpressure diaphragm which, together with a control diaphragm forms an overpressure chamber in the housing of the valve for achieving an overpressure in the inlet chamber leading to the breathing organs of the user during both the inhalation phase and the exhalation phase. The regulated pressure in the overpressure chamber can be varied and even removed entirely by a simple manual adjustment. Consequently, the breathing valve is suitable for use in an environment of noxious gases or for diving under water.

In accordance with a preferred embodiment of the present invention, an inlet chamber which communicates with an inlet opening and with the passage to the user is bordered at one portion by a control diaphragm, movement of which operates a lever to control an inlet valve. The exhalation valve from the inlet chamber may be provided in the control diaphragm; and this has the advantage that it eliminates a hydrostatic pressure difference between the control diaphragm and the exhalation valve, as a result of which the operation of the breathing valve becomes independent of the position of the valve in the water and there is no risk of blowing out air from the valve or that breathing through the valve should become cumbersome.

In this preferred arrangement, an overpressure diaphragm opposes the control diaphragm forming therebetween an overpressure chamber, a build-up of pressure in which moves the control diaphragm to cause the inlet valve to open. Springs act on the overpressure diaphragm urging it toward the control diaphragm, and hence toward the inlet valve open position. These springs act on their other end against a removable, adjustable lid. Consequently, the springs are easily removable for the purpose of removing the overpressure chamber, thereby adopting the breathing valve for use in diving under water.

Thus, it is a purpose of this invention to provide a new and improved breathing valve of the type described in which an overpressure is created during both inhalation and exhalation.

It is another object of this invention to provide a new and improved breathing valve of the type described which may be converted between overpressure and non-overpressure in a relatively simplified manner.

Other objects and advantages of the present invention will become apparent from the detailed description to follow.


There follows a detailed description of the preferred embodiment of the present invention to be read together with the accompanying drawing.

FIG. 1 is a sectional view through a breathing valve constructed in accordance with the present invention.

FIG. 2 is a horizontal sectional view taken along line 2--2 of FIG. 1.


Referring now to the drawings, like elements are represented by like numerals throughout the two views.

The breathing valve comprises a housing 10 having an inlet chamber 11. In communication with this inlet chamber 11 is an inlet tube 12, the opening of which is controlled by an inlet valve 13. An opening 14 leads from this inlet chamber to the breathing organs of the user. The inlet chamber is also bounded in part by a control diaphragm 15 in which are formed a plurality of openings 16. These openings 16 are covered by an exhalation valve 17 which is held firmly against the diaphragm 15 to close the opening 16 except when it is resiliently biased away from the opening 16 during exhalation.

Above the control diaphragm 15 is an overpressure diaphragm 20 including as a part thereof a central stud 21 which extends down to the exhalation valve 17 and holds the same against the control diaphragm 15. An overpressure chamber is formed between the diaphragms 15 and 20. The diaphragm 20 is held in place by the force of two springs 26 and 27. Spring 26 acts at its lower end against the other circumference of the diaphragm 20 while the spring 27 acts against the central stud 21. At their upper ends, both springs abut a lid 23 having outlet openings 24 formed therein. This lid is vertically adjustable relative to the housing 10, for example by means of a threaded engagement 28 between the lid 23 and the housing 10. From the overpressure chamber 22, air flows around the outer periphery of diaphragm 20, lifting the springs 26 in the process, whereby the air enters the exhalation chamber 25 from which it flows through the opening 24 to the surrounding atmosphere. It will be seen that by controlling the force of spring 26 against the outer periphery of diaphragm 20, one controls the level of pressure at which the air in overpressure chamber 22 enters the exhalation chamber 25.

In the inlet chamber 11 there is provided a lever 30 pivotally connected at 31 and connected at its right-hand end by means of connection 32 to the inlet valve 13. Downward movement at the left-hand end of the lever 30 opens the inlet valve 13. In the absence of such downward movement, the spring 33 normally holds the inlet valve closed.

In operation, an overpressure is produced in the inlet chamber 11 of the breathing valve when the lid 23 is adjusted vertically to a position in which the two springs 26 and 27, which function independently of each other, are compressed against the diaphragm 20. The control spring 27 loads the lever 30 through the central stud 21 and the control diaphragm 15 causing the inlet valve 13 to open so that a flow of gas is created into the inlet chamber. A portion of this inflowing gas flows through the exhalation valve 17 so that the pressure in the overpressure chamber 22 reaches the same value as the pressure in the inlet chamber 11. The pressure increases until a balance is obtained between the outwardly directed forces on the overpressure diaphragm 20 (equal to the pressure multiplied with the effective area of the diaphragm 20) and the force from the control spring 27 acting in the reverse direction. The inlet valve 13 then closes when a balance has been achieved since the lever 30 in this position is not influenced by any downward force at its left end, and hence the spring 33 is free to close the valve. The other spring 26 loads the outer circumference of the diaphragm 20 so that the overpressure caused by the control spring 27 does not cause any leakage.

Independently of whether or not an increased pressure is present in the overpressure chamber 22, if the pressure in the inlet chamber 11 is decreased during inhalation with respect to the pressure in the overpressure chamber 22, this pressure difference results in a force acting on the lever 30 from the control diaphragm 15, the lever 30 thus opening the inlet valve 13 so that gas can flow into the inlet chamber 11. The pressure in the overpressure chamber 22 is maintained constant during inhalation due to the fact that the spring 27 loads the overpressure diaphragm 20. If the pressure in overpressure chamber 22 leaks out, the control spring 27 acts downwardly through the central stud 21 to move the lever 30 downwardly mechanically, thus opening the inlet valve 13 once again permitting additional gas to flow into the inlet chamber. During exhalation, the exhalated gas is expelled through the valve 17 and into the overpressure chamber 22, thereby causing a slight increase in the pressure over the original pressure value. This increased pressure then influences the entire overpressure diaphragm 20 which opens completely permitting some of this excess gas to be removed.

When it is desired to remove from this apparatus the overpressure feature, thereby adopting the device for use in diving under water, the lid 23 is taken off and the two springs 26 and 27 and the overpressure diaphragm 20 are removed. Of course a suitable means would be provided to hold the exhalation valve 17 against the diaphragm 15 to cover the openings 16.

Although the invention has been described in considerable detail with respect to a preferred embodiment thereof, it will be apparent 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.