Claims
- 1. A pressure regulator having an inlet for high pressure gas and an outlet, the regulator comprising a housing defining first and second chambers separated by a movable partition, the first chamber being vented to a reference pressure and the housing including fulcrum means to define an eccentric pivot axis for a rigid central part of the partition, the second chamber including a pilot jet facing the partition and closeable thereby at a position on the side of the pivot axis remote from the centroid of the rigid portion of the partition and a vent leading from the second chamber for fluid communication with the outlet of the pressure regulator, the housing further defining a third chamber communicating with the pilot jet and partially defined by a valve member adapted for movement between an open position and a closed position, to respectively allow or deny access from a high pressure supply port to the outlet of the pressure regulator, the high pressure being supplied to the third chamber via an orifice such that while a predetermined back pressure is applied to the outlet the rigid portion of the partition is held in a position to close the pilot jet and the valve member is held in its closed position by the pressure in the third chamber, and that when the back pressure is reduced to below a predetermined value the pilot jet is opened, the pressure in the third chamber reduces, and the valve member moves toward its open position.
- 2. A pressure regulator according to claim 1, wherein the partition comprises a diaphragm having a rigid central portion and a flexible periphery.
- 3. A pressure regulator according to claim 1, wherein the partition is a tilting piston having a rigid central part and a resilient sealing element about its periphery.
- 4. A pressure regulator according to claim 1, wherein the fulcrum means comprises a number of projections extending across the first chamber to contact the central portion of the partition along a line extending between its centroid and the position of the pilot jet.
- 5. A pressure regulator according to claim 1, wherein the valve member is a resilient element which is unstressed in its closed position and is resiliently deformed in its open position.
- 6. A pressure regulator according to claim 5, wherein the valve member is a resilient disc secured in the housing about its periphery, the high pressure supply port being arranged opposite a central area of the disc and the outlet being in communication with a number of openings spaced about the supply port and facing the disc, the supply port and the openings being occluded by the disc in its closed position.
- 7. A pressure regulator according to claim 1, wherein the orifice connecting the third chamber to the high pressure supply port comprises a passage of small diameter passing through the valve member.
- 8. A pressure regulator according to claim 1, wherein a resilient element biases the partition towards a position in which the pilot jet is unobstructed.
- 9. A pressure regulator having an inlet for high pressure gas and an outlet, said regulator comprising a housing defining first and second chambers separated by a movable partition, wherein said movable partition comprises a rigid central portion, passage means for permitting communication between said first chamber and a reference pressure, said housing carrying pivot means for operative engagement with said movable partition as to thereby establish a pivot axis about which said movable partition may rotate, wherein said pivot axis is located as to define an axis for pivotal rotation which is situated eccentrically of a mid-portion of the rigid central portion of said movable partition, the second chamber including a pilot jet facing the partition and closeable thereby at a position on the side of the pivot axis remote from the centroid of the rigid portion of the partition and a vent leading from the second chamber for fluid communication with the outlet of the pressure regulator, the housing further defining a third chamber communicating with the pilot jet and partially defined by a valve member adapted for movement between an open position and a closed position, to respectively allow or deny access from a high pressure supply port to the outlet of the pressure regulator, the high pressure being supplied to the third chamber via an orifice such that while a predetermined back pressure is applied to the outlet the rigid portion of the partition is held in a position to close the pilot jet and the valve member is held in its closed position by the pressure in the third chamber, and that when the back pressure is reduced to below a predetermined value the pilot jet is opened, the pressure in the third chamber reduces, and the valve member moves towards its open position.
Priority Claims (2)
| Number |
Date |
Country |
Kind |
| 8611113 |
May 1986 |
GBX |
|
| 8629099 |
Dec 1986 |
GBX |
|
Parent Case Info
This is a continuation of application Ser. No. 44,338, filed Apr. 30, 1987, now abandoned.
This invention relates to pressure regulators, and is particularly concerned with demand valves for breathing apparatus, whereby breathable gas is supplied automatically to a facepiece or mask in accordance with the wearer's respiratory requirements. Most particularly, the present invention relates to demand valves of the positive pressure type which continually maintain a pressure slightly greater than that of the surrounding atmosphere within a facepiece or helmet, so as to prevent inward leakage.
In such demand valves, flow of gas to the wearer is controlled by movement of a sensitive diaphragm having one face exposed to atmospheric pressure, and the other face to pressure within the facepiece.
In practice, very small changes in pressure across the diaphragm, of the order of 1 millibar or less, may be required to regulated the flow of gas entering the valve at a supply pressure of typically 7 bar or greater, and in order to gain the necessary mechanical advantage, known valves generally employ various lever and spring arrangements. Alternatively, valves of the Pilot or two-stage type are sometimes used, wherein the mechanical advantage is obtained by gas pressures, However, such valves still generally employ pivoted levers as a means of transmitting diaphragm movement to the valve, often because the direction of diaphragm movement is inconvenient and has to be reversed.
In known demand valves, the positive pressure is usually established by biasing the diaphragm with a spring.
The reliability of breathing apparatus is of the upmost importance, and to this end it is desirable for its construction to be very simple.
According to a first aspect of the present invention, a pressure regulator comprises a housing defining first and second chambers separated by a movable partition, the first chamber being provided with an inlet port facing towards, and sealingly closeable by, a rigid central portion of the partition at a position remote from its centroid and an outlet port, and the second chamber being vented to a reference pressure, and the regulator including means extending between the housing and the central portion of the partition to define a pivot axis for the diaphragm extending between its centroid and the position of the inlet port.
The partition may comprise a diaphragm having a rigid central portion and a flexible peripheral portion sealingly secured to isolate the first and second chambers, or may comprise a piston having a rigid central disc and a peripheral sealing element capable of sealing against the inner surface of the housing as the piston is tilted.
In a first embodiment of the invention, the means defining the fulcrum comprises one or more projections contacting the central portion of the diaphragm on its side remote from the inlet port. Two projections may be provided, one on either side of a line joining the inlet port to the centroid of the central portion of the diaphragm. Most preferably, the diaphragm is circular and the rigid central portion is formed by a rigid circular backing plate fixed concentrically to the diaphragm on its side remote from the inlet port.
In a second embodiment of the present invention, the central portion of the diaphragm is attached to the housing via a hinged joint defining a pivot axis for the diaphragm, the pivot axis extending between the centroid of the rigid portion of the diaphragm and the inlet port.
The hinged joint may comprise one or more pillars or brackets extending from the housing toward the diaphragm and joined by a pivot pin to a bracket or brackets mounted on the diaphragm.
A second aspect of the invention utilises the valving device described above as a pilot valve, to operate a pressure regulator of reduced overall proportions. In accordance with this second aspect of the invention, a pressure regulator comprises a housing defining first and second chambers separated by a movable partition, the first chamber being vented to the surroundings and the housing including fulcrum means to define an eccentric pivot axis for a rigid central part of the partition, the second chamber including a pilot jet facing the partition and closeable thereby at a position on the side of the pivot axis remote from the centroid of the rigid portion of the partition, and a vent to the outlet of the pressure regulator, the housing further defining a third chamber communicating with the pilot jet and partially defined by a valve member adapted to deny access from a high pressure supply port to the outlet port of the demand valve, high pressure being supplied to the third chamber via an orifice, such that while a predetermined back pressure is applied to the outlet, the rigid portion of the partition is held in a position to close the pilot jet and the valve member is held in its closed position by the high pressure supplied to the third chamber via the orifice, and that when the back pressure is removed the pilot jet is opened, the pressure in the third chamber reduces and the valve member moves to permit access from the supply port to the outlet.
US Referenced Citations (7)
Foreign Referenced Citations (3)
| Number |
Date |
Country |
| 693244 |
Jun 1953 |
GBX |
| 2075848 |
Nov 1981 |
GBX |
| 2116852 |
Oct 1983 |
GBX |
Continuations (1)
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Number |
Date |
Country |
| Parent |
44338 |
Apr 1987 |
|
Patent Grant
4821767
