GB2077397A

GB2077397A - Vacuum regulator

Info

Publication number: GB2077397A
Application number: GB8117014A
Authority: GB
Original assignee: Medishield Corp Ltd
Current assignee: Edwards High Vacuum International Ltd
Priority date: 1980-06-06
Filing date: 1981-06-03
Publication date: 1981-12-16
Also published as: AU539461B2; GB2077397B; AU7138381A; NZ193953A

Abstract

A vacuum regulator includes a body 10 having parallel passages 11, 12. A cap is attached by a screw thread over one end of the body 10 and defines with body 10 a chamber containing a diaphragm 22 which is arranged to co-operate with a seating 13 at the end of passage 11. A vent 25 is provided in the cap on the side of the cap opposite to the seating 13. The diaphragm is held in the cap at its periphery so that rotation of the cap moves the diaphragm relative to the seat and thus adjust the regulator setting. <IMAGE>

Description

SPECIFICATION A vacuum regulator This invention relates to a vacuum regulator.

High vacuum regulators are known and according to a conventional construction, a diaphragm within the body of the regulator is moved by a combination of differential pressure and counterbalanced springs on one or both sides of the diaphragm. The regulator is adjusted by adjusting the rating of the springs. The design of such regulators leads to certain difficulties, one of which is the adjustment of the spring rates during assembly.

An aim of the present invention is to provide a vacuum regulator which is of a straight forward design and allows for ease of manufacture and maintenance.

According to the present invention, a vacuum regulator comprises a body having first and second passages, a cap adjustably mounted on said body, said cap defining with said body a chamber, a seating at the end of said first passageway where it opens into said chamber, a diaphragm mounted within said cap and engageable with said seating to thereby close said first passageway and vent means for ventilating to atmosphere the side of the diaphragm which is opposite to the side thereof which is engageable with said seating.

An embodiment of the invention will now be described, by way of example, reference being made to the Figure of the accompanying diagrammatic drawing which is a longitudinal cross-section through a regulator with the regulator being illustrated in an operative condition.

The body 10 is shown in a preferred form as being generally of cylindrical shape. A first passageway 11 is perferably centrally disposed in the body 10 and a second passageway 12 is situated parallel thereto. A vacuum source is coupled by conventional means (not shown) to passageway 11. During operation a regulated vacuum exists in passageway 11 and this passageway is coupled, once again by conventional means (not shown), to the system in which a regulated vacuum is to be drawn. If the regulator is to include a vacuum gauge a third passageway (not shown) can be included with the gauge coupling into this third passageway.

The inner end of passageway 11 terminates in a seat 13 which is perferably formed by an annular projection 14 at the inner end 1 5 of body 10.

An adjusting bonnet 1 6 is formed by a cap having a peripheral skirt 1 7 which fits over body 1 0. The inner peripheral surface of skirt 1 7 has a threaded portion 1 8 which engages with a complementary threaded portion 1 9 on the wall of body 10 adjacent end 1 5. An O-ring seal 20 is located within an annular groove 21 in body 10.

This O-ring seal 20 engages with the inner peripheral wall surface of skirt 17 outward of the interengaging threaded portions 1 8 and 19.

A rubber diaphragm 22 is clamped tightly between the end wall 23 of bonnet 16 and a peripheral flange 24 which projects inwardly from skirt 1 7. A very small vent 25 is formed in the end wall 23. In the preferred form this vent is in the order of 0.028 inch. It has been found that if the diameter of the vent 25 is too large the diaphragm tends to resonate during operation.

To further descirbe the invention reference will be made to the operation of the regulator. In the off position the rubber diaphragm 22 is screwed tight against the protruding seat 1 3 of the regulator body 10. As the adjusting bonnet 1 6 is screwed out the rubber diaphragm 22 is also drawn out being clamped as previously described about its periphery. Due to the differential pressure of atmosphere on the outer surface 26 and the supply vacuum through the central passageway 11 on the inner surface 27, the central portion of the diaphragm 22 is still held on the seat 13.Once the bonnet 1 6 has been screwed out sufficiently for the elasticity of the diaphragm 16 to overcome the suction holding the diaphragm on the seat 1 3 a flow will result across the seat tending to draw vacuum in passageway 12 and the system beyond. This vacuum will act on the full exposed surface 27 of the diaphragm 22 and therefore, at less vacuum than the supply, tend to puil the diaphragm back towards the seat 1 3 reducing the flow and thus regulating the vacuum in the system beyond the seat. If the vaccum in the regulated system reduces the diaphragm 22 will move away from the seat 13, thus allowing more flow and tending to maintain the system vacuum at a constant level.

The regulator of the present invention is of a simple, straight forward design which allows for ease of manufacture and maintenance. The resilience of the rubber diaphragm itself provides the force necessary to balance the differential pressure which tends to draw the diaphragm toward the seat. The small vent opening in the bonnet of the regulator not only vents the chamber defined by the diaphragm inside of the bonnet but also permits pneumatic dampening of the diaphragm. The absence of any counterbalance springs and the difficulties of adjusting spring tensions during assembly which are associated with conventional designs are overcome.

1. A vacuum regulator comprising a body having first and second passages, a cap adjustably mounted on said body said cap defining with said body a chamber, a seating at the end of said first passageway where it opens into said chamber, a diaphragm mounted within said cap and engageable with said seating to thereby close said first passageway and vent means for venting to atmosphere the side of the diaphragm which is opposite to the side thereof which is engageable with said seating.

2. A vacuum regulator as claimed in claim 1 wherein said cap has a side wall and an end wall,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A vacuum regulator This invention relates to a vacuum regulator. High vacuum regulators are known and according to a conventional construction, a diaphragm within the body of the regulator is moved by a combination of differential pressure and counterbalanced springs on one or both sides of the diaphragm. The regulator is adjusted by adjusting the rating of the springs. The design of such regulators leads to certain difficulties, one of which is the adjustment of the spring rates during assembly. An aim of the present invention is to provide a vacuum regulator which is of a straight forward design and allows for ease of manufacture and maintenance. According to the present invention, a vacuum regulator comprises a body having first and second passages, a cap adjustably mounted on said body, said cap defining with said body a chamber, a seating at the end of said first passageway where it opens into said chamber, a diaphragm mounted within said cap and engageable with said seating to thereby close said first passageway and vent means for ventilating to atmosphere the side of the diaphragm which is opposite to the side thereof which is engageable with said seating. An embodiment of the invention will now be described, by way of example, reference being made to the Figure of the accompanying diagrammatic drawing which is a longitudinal cross-section through a regulator with the regulator being illustrated in an operative condition. The body 10 is shown in a preferred form as being generally of cylindrical shape. A first passageway 11 is perferably centrally disposed in the body 10 and a second passageway 12 is situated parallel thereto. A vacuum source is coupled by conventional means (not shown) to passageway 11. During operation a regulated vacuum exists in passageway 11 and this passageway is coupled, once again by conventional means (not shown), to the system in which a regulated vacuum is to be drawn. If the regulator is to include a vacuum gauge a third passageway (not shown) can be included with the gauge coupling into this third passageway. The inner end of passageway 11 terminates in a seat 13 which is perferably formed by an annular projection 14 at the inner end 1 5 of body 10. An adjusting bonnet 1 6 is formed by a cap having a peripheral skirt 1 7 which fits over body 1 0. The inner peripheral surface of skirt 1 7 has a threaded portion 1 8 which engages with a complementary threaded portion 1 9 on the wall of body 10 adjacent end 1 5. An O-ring seal 20 is located within an annular groove 21 in body 10. This O-ring seal 20 engages with the inner peripheral wall surface of skirt 17 outward of the interengaging threaded portions 1 8 and 19. A rubber diaphragm 22 is clamped tightly between the end wall 23 of bonnet 16 and a peripheral flange 24 which projects inwardly from skirt 1 7. A very small vent 25 is formed in the end wall 23. In the preferred form this vent is in the order of 0.028 inch. It has been found that if the diameter of the vent 25 is too large the diaphragm tends to resonate during operation. To further descirbe the invention reference will be made to the operation of the regulator. In the off position the rubber diaphragm 22 is screwed tight against the protruding seat 1 3 of the regulator body 10. As the adjusting bonnet 1 6 is screwed out the rubber diaphragm 22 is also drawn out being clamped as previously described about its periphery. Due to the differential pressure of atmosphere on the outer surface 26 and the supply vacuum through the central passageway 11 on the inner surface 27, the central portion of the diaphragm 22 is still held on the seat 13.Once the bonnet 1 6 has been screwed out sufficiently for the elasticity of the diaphragm 16 to overcome the suction holding the diaphragm on the seat 1 3 a flow will result across the seat tending to draw vacuum in passageway 12 and the system beyond. This vacuum will act on the full exposed surface 27 of the diaphragm 22 and therefore, at less vacuum than the supply, tend to puil the diaphragm back towards the seat 1 3 reducing the flow and thus regulating the vacuum in the system beyond the seat. If the vaccum in the regulated system reduces the diaphragm 22 will move away from the seat 13, thus allowing more flow and tending to maintain the system vacuum at a constant level. The regulator of the present invention is of a simple, straight forward design which allows for ease of manufacture and maintenance. The resilience of the rubber diaphragm itself provides the force necessary to balance the differential pressure which tends to draw the diaphragm toward the seat. The small vent opening in the bonnet of the regulator not only vents the chamber defined by the diaphragm inside of the bonnet but also permits pneumatic dampening of the diaphragm. The absence of any counterbalance springs and the difficulties of adjusting spring tensions during assembly which are associated with conventional designs are overcome. CLAIMS

2. A vacuum regulator as claimed in claim 1 wherein said cap has a side wall and an end wall, said side wall having a screw threaded portion on its inner surface which is engaged with a complementary threaded portion on said body, thereby permitting said end wall to be moved toward or away from said seating.

3. A vacuum regulator as claimed in claim 2 wherein the diaphragm is mounted by the peripheral edge therefore so as to form with said end wall a chamber into which said vent means opens.

4. A vacuum regulator as claimed in claim 3 wherein said vent means is a very small diameter bore through said end wall.

5. A vacuum regulator as claimed in claim 3 or 4 wherein the peripheral edge of said disphragm is clamped between said end wall and a peripheral flange extending about the inner surface of said side wall.

6. A vacuum regulator as claimed in claim 4 wherein the bore is of a diameter which is in the order of 0.028 inch.

7. A vacuum regulator as claimed in any one of the preceding claims wherein the first passageway extends into said chamber thereby forming an extended portion which provides said seating.

8. A vacuum regulator as claimed in any one of claims 2 to 6 wherein seating means is located between said body and the inner surface of said side wall.

9. A vacuum regulator as claimed in any one of the preceding claims further including said means for coupling said first passageway to a vacuum source and means for coupling said second passageway to a system in which a vacuum is to be drawn.

10. A vacuum regulator constructed and arranged substantially as herein described with reference to and as illustrated in the accompanying drawings.