NZ193953A - Vacuum regulator:diaphragm responds to change in pressure - Google Patents

Description

193953 N.Z. No. 193953 6 June 1980 NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION A VACUUM REGULATOR .....

We, NEW ZEALAND INDUSTRIAL GASES LIMITED, a New Zealand company of Kings Crescent, Lower Hutt, New Zealand, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- 193953 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.

The object 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.

Broadly, the invention provides a vaccum regulator comprising a body having first and second passages, a cap mounted on said body, the cap having a side wall and an end wall which together with the body define a chamber, said first and second passages opening into said chamber, a seating at the end of said first passage where it opens into the chamber, the mounting of said cap on said body being such that the position of the end wall relative to said seating can be adjusted, a diaphragm mounted with the cap and with the or a part of the end wall forms a venting chamber said diaphragm being engageable with the seating to close the first passageway and an opening-through said end wall into said venting chamber for venting to atmosphere that side of the diaphragm which is opposite to the side which is engageable with said seating.

In more fully describing the invention, reference will be made to the accompanying drawing which is a longitudinal cross section through the regulator with the regulator being illustrated in an operative condition.

I9S953 The body 10 is shown in a preferred form as being generally of cylindrical shape. A first passageway 11 is preferably 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 12 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 I with passageway 12 with the gauge coupling into this third passageway and connecting) The inner end of passageway 11 terminates in a seat 13 which is preferably formed by an annular projection 14 at the inner end 15 of body 10.

An adjusting bonnet 16 is formed by a cap having a peripheral skirt 17 which fits over body 10. The inner peripheral surface of skirt 17 has a threaded portion 18 which engages with complementary threaded portion 19 on the wall of body 10 adjacent end 15. 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 18 and 19.

A rubber diaphragm 22 is clamped tightly between the end wall 23 of bonnet 16 and a peripheral flange 24 which 41 N,2. PATENT OFFICE v' ... 193953 projects inwardly from skirt 17. 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 b£en found that if the diameter of the vent 25 is too large the diaphragm tends to resonate during operation.

To further describe 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 13 of the regulator body 10. As the adjusting bonnet 16 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 16 has been screwed out sufficiently for the elasticity of the diaphragm 22 to overcome the suction holding the diaphragm on the seat 13 a flow will result across the seat tending to draw a 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 pull the diaphragm back towards the seat 13 reducing the flow and thus regulating the vacuum in the system beyond the seat. If the vacuum in the regulated system reduces the diaphragm 22 will move away from the seat 13, thus allowing , n—^iTwrrimr tt" "trnit-ii—— PAT£NT OFFICE 23SIM983 , RECEIVED 193953 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 and inside of the bonnet but also premits 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.

I93*53

Claims (10)

WHAT WE CLAIM IS:

1. A vacuum regulator comprising a body having first and second passages, a cap mounted on said body, the cap having a side wall and an end wall which together with the body define a chamber, said first and second passages opening into said chamber, a seating at the end of said first passage where it opens into the chamber, the mounting of said cap on said body being such that the position of the end wall relative to said seating can be adjusted, a diaphragm mounted with the cap and with the or a part of the end wall forms a venting chamber said diaphragm being engageable with the seating to close the first passageway and an opening-through said end wall into said venting chamber for venting to atmosphere that side of the diaphragm which is opposite to the side which is engageable with said seating.

2. A vacuum regulator as claimed in claim 1 wherein said side wall has 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 vaccum 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 very small bore opens.

4. A vacuum regulator as claimed in claim 3 wherein the pheripheral edge of said diaphragm is clamped between said end wall and a peripheral flange extending about the inner surface of said side wall. - 6 - rtmi

5. A vacuum regulator as claimed in any one of claims 1 to 4 wherein the opening in said end wall is a bore which is very small relative to the diameter of the first or second passage.

6. A vacuum regulator as claimed in claim 5 wherein the diameter of the very small bore is substantially 0.028 inch.

7. A vacuum regulator as claimed in any one of the preceding claims wherein the first passage 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 7 wherein a seal 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 means for coupling said first passage to a vacuum source and means for coupling said second passage to a system in which a vacuum is to be drawn.

10. A vacuum regulator substantially as herein described with reference to the accompanying drawings. NEW ZEALAND INDUSTRIAL GASES LIMITED By Their Attorneys HENRY HUGHES LIMITED