WO2004092860A2

WO2004092860A2 - Tamper resistant pressure regulator

Info

Publication number: WO2004092860A2
Application number: PCT/US2004/011150
Authority: WO
Inventors: Gregory S Kalata; David J Hasak; Eric M Kvarda; Ii Charles W Hayes; Paul Eidsmore
Original assignee: Swagelok Company
Priority date: 2003-04-10
Filing date: 2004-04-09
Publication date: 2004-10-28
Also published as: WO2004092860A3; TW200502726A

Abstract

A tamper-resistant pressure regulator (10) is provided in which a cover (24) is mechanically coupled to an Actuator adjustment assembly (14) whereby removal of the cover causes a change in the regulator pressing setting. The actuator adjustment assembly (14) includes disk (26), a spring (28) and a spring plate (30). The regulator pressure is set by adjusting the amount of compression of the spring (28), in particular by changing the axial position of the actuator disk (26) and spring plate (30) by inserting a tool on the tool interface (36) through the hole cap (38). Since the cover (24) and the actuator disk (26) are coupled by threads (32, 34), the cover cannot be repositioned without to change the setting pressure, thus allowing such change or tampering to be detected after the fact.

Description

TAMPER RESISTANT PRESSURE REGULATOR

BACKGROUND OF THE INVENTION

Pressure regulators are used to control either or both of the upstream or downstream fluid pressure at the inlet and outlet ports of the regulator. Many pressure regulator designs have been developed over the years, most recently in connection with surface mount modular gas flow systems. Such regulators are described in United States Patent Nos. 5,694,975 PRESSURE REGULATOR; 5,303,734 PRESSURE REGULATOR; 6,047,728 SPRING LOADED BELLOWS REGULATOR; 5,033,505 PRESSURE REGULATOR AND METHOD OF ASSEMBLING SAME issued to Eidsmore the entire disclosures of which are fully incorporated herein by reference. The present invention may be used, however, with other regulator designs.

Pressure regulators typically are designed to be adjustable in the sense that the regulated or set pressure can be selected or changed after final assembly of the regulator. These adjustments often are made in the field, even after the regulator is installed in a fluid circuit. In some cases, it may be desirable to adjust the set pressure only once. For example, a fluid system integrator may want to select the set pressure of a regulator and have it fixed at that pressure even after the system is installed in the field. Or in other cases, it may be desired to make it more difficult for an adjustment to be made, such as by a field operator or technician, but still allow adjustment by authorized personnel. SUMMARY OF THE INVENTION

The present invention contemplates different techniques for providing a tamper-resistant or adjustment control pressure regulator. The tamper resistant feature may be used to discourage or substantially increase the difficulty in adjusting the regulator after final settings are made, or may make unauthorized adjustments difficult while still allowing for adjustment when using the proper tools. In one embodiment, a cover is mechanically coupled to an adjustment mechanism so that r repositioning of the cover causes a concomitant change in the pressure setting.

The invention also contemplates a method for making a pressure regulator tamper resistant, comprising the steps of installing a cover on the regulator; mechanically coupling the cover to a pressure adjustment mechanism of the regulator; and adjusting the regulator pressure setting to a desired value, wherein the mechanical coupling causes the adjustment mechanism to change the pressure setting when the cover is repositioned.

These and other aspects and advantages of the present invention will be readily appreciated and understood from the following detailed description of the invention in view of the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a partial longitudinal cross-section in elevation of a tamper-resistant pressure regulator incorporating one embodiment of the invention;

Fig. 2 is an isometric view of the illustration of Fig. 1; Fig. 3 is a isometric view of the assembly of Fig. 1;

Fig. 4 is a top isometric view of the assembly of Fig. 1; and

Fig. 5 is a cross-sectional view of another embodiment of the invention.

Description of the Invention The present invention is directed to the concept of a tamper resistant pressure regulator by which a pressure setting is easily adjustable only by authorized personnel. In one embodiment, the invention contemplates a regulator cover that restricts access to the adjustment mechanism of the regulator.

Additionally, various aspects of the invention are described and illustrated herein as embodied in combination in the exemplary embodiments. These various aspects however may be realized in many alternative embodiments, either alone or in various combinations and sub- combinations thereof. Still further, various alternative embodiments as to the various aspects and features of the invention, such as alternative materials, structures, configurations, methods, devices and so on may be described herein, but such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether known or later developed. Those skilled in the art may readily adopt one or more of the aspects of the invention into additional embodiments within the scope of the present invention even if such embodiments are not expressly disclosed herein. Additionally, even though some features and aspects of the invention may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless so expressly stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present invention however, such values and ranges are not to be construed in a limiting sense and are only intended to be critical values if so expressly stated.

With reference to Figs. 1-4, in the exemplary embodiment a pressure regulator 10 includes a regulator assembly 12 and an actuator adjustment assembly 14. The exemplary embodiment illustrates a surface mount regulator such as may typically be used in a modular fluid assembly in the semiconductor industry, however, the present invention may be used with other regulator designs both for surface mount and non-surface mount configurations.

The regulator assembly 12 includes a body 16 having a mounting flange 18 at one end thereof. The flange 18 may be used, for example, as a mounting flange to attach the regulator 10 to another component or structure. The body 16 encloses a regulator flow control assembly, such as is described in the above-incorporated patents, the details of which need not be described herein for a complete understanding of the present invention. Associated with the body 16 is a bonnet nut 20 which typically is used to threadably receive a bonnet (not shown) that secures the actuator assembly 14 to the body 16. The bonnet nut 20 includes a male threaded portion 22. In the present invention, the bonnet nut 20 mates with a female threaded cover 24 described in more detail hereinbelow.

The actuator assembly 14 includes an actuator disk 26, an adjustment element or spring 28 and a spring plate 30, which in this embodiment make up a pressure adjustment mechanism or means for adjusting the pressure regulator setting. The regulator pressure is set by adjusting the amount of compression of the spring 28. The spring compression is adjusted in this example by changing the axial position of the actuator disk 26 and spring plate 30. The cover 24 includes internal threads 32 that cooperate with external threads 34 on the actuator disk 26. By turning the disk 24 clockwise or counter-clockwise the spring 28 compression can be increased or decreased by a corresponding axial displacement of the disk 24 and the spring plate 30. Rotation of the disk 26 may be realized in a number of different ways. For example, the disk 26 may include a tool interface 36, such as, for example, an Allen keyway, or a keyway requiring a special tool to turn the disk, or may be as simple as a screwdriver slot. Preferably, although not necessarily, the disk 26 is adjusted to its final setting after the cover 24 is installed onto the bonnet nut 22 to a fully torqued condition.

The cover 24 may be torqued down by any convenient technique such as providing spanner wrench holes. By having the cover 24 and actuator disk 26 threadably coupled, the cover 24 preferably cannot be repositioned such as being removed from or loosened from the assembly 10 without changing the set pressure, thus allowing such tampering or changes to be detected after the fact. The bonnet nut-to-cover torque preferably is substantially higher than the disk-to-cover torque. Friction between the disk and the cover will in most cases prevent removal of the cover without changing the pressure setting.

The cover 24 includes an access hole 38 through which an adjustment tool (not shown) such as a screwdriver, Allen wrench or other tool is inserted to turn the disk 26. This final adjustment of the set pressure typically will be made at the regulator manufacturer, but may also be made in the field or readjusted in the field. To discourage unauthorized adjustment, the access hole 38 may be covered with a sticker, cap, cover or otherwise plugged so that post-adjustment access through the hole 38 can be detected. Such detection can be done in a wide variety of ways including but not limited to visual inspection, electronic monitoring by an electrical circuit or a video device, and so on. A sensor such as an electrical sensor for example may be used to detect disturbance of the cover 24, the hole 38 cap, change in the pressure setting of the regulator and so on.

With reference to Fig. 3, the final assembly 10 after adjustment presents a sleek smooth profile to the cover that cannot be easily unscrewed from the bonnet nut 20. The cover 24 may be made of a suitable high strength plastic or metal so that it can be tightened to the bonnet 20 with a high torque, thus making disassembly in the field difficult. Still further, the cover 24 can be permanently attached to the regulator, for example by welding, brazing, an adhesive and so on to prevent removal of the cover without substantial modification thereof. With reference to Fig. 5 we illustrate another embodiment of the invention. Fig. 5 only illustrates in section the upper portion of the cover and actuator assembly. The cover may be attached to the regulator as in the first embodiment or in any other convenient manner.

In this embodiment, the cover or cap 50 includes internal threads 52 that permit the cover 50 to be tightly installed onto the threaded bonnet nut 20. The actuator adjustment includes a spring 54 with a spring plate 56, the axial position of which controls compression of the spring 54.

The axial position of the plate 56 is selected by adjusting a set screw 58 or other suitable device. In this embodiment, the set screw 58 is threadably inserted into a threaded access hole 60 that extends through the cover 50. The set screw 58 may be threaded into or otherwise engages the spring plate 56. A plug, cap screw 62 or sticker or other suitable device may be used to cover the access hole 60. A locking set screw may be used or other locking mechanism may be used to reduce the opportunity to change the pressure setting after it has been set. For example, the set screw 58 could be provided with a special keyway that would require a special tool to turn the screw for adjusting the pressure setting of the regulator. An optional second set screw 64 or other suitable device may be used to couple the cover

50 to the bonnet nut 20. This feature may also be used in the first embodiment described hereinabove.

As in the first embodiment, if the cover 50 is removed from the assembly, the pressure setting changes as well. Thus, the cover cannot be removed in order to gain access to the adjustment mechanism without changing the operation of the regulator and its pressure setting.

The invention has been described with reference to the exemplary embodiments. Modifications and alterations will occur to others upon a reading and understanding of this specification. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

CLAIMSHaving thus described our invention, we claim:

1. A pressure regulator, comprising: a regulator body, a pressure adjustment mechanism and a cover for said adjustment 5 mechanism; said cover being installed on said body; said cover and said adjustment mechanism being mechanically coupled so that repositioning said cover causes a change in the pressure setting.

2. The regulator of claim 1 wherein said cover is threadably installed on said body such that rotation of said cover causes a change in the pressure setting. 0

3. The regulator of claim 2 wherein said cover is threadably coupled to said adjustment mechanism.

4. The regulator of claim 1 wherein said adjustment mechanism comprises a disk that is threadably installed in said cover; said disk being adjustable by rotation relative to said cover, whereby movement of said disk changes the pressure setting of the regulator.

5 5. The regulator of claim 4 wherein position of said disk controls compression of a bias element that sets the pressure of the regulator.

6. The regulator of claim 1 wherein said adjustment mechanism comprises a threaded element that is threadably installed in said cover.

7. The regulator of claim 6 wherein said threaded element comprises a disk; said 0 disk being adjustable by rotation relative to said cover, whereby movement of said disk changes the pressure setting of the regulator.

8. The regulator of claim 6 wherein said threaded element comprises a screw whereby axial position of said screw adjusts the pressure setting of the regulator by changing compression of a spring.

5 9. The regulator of claim 1 wherein said cover comprises an access opening through which said adjustment mechanism is accessible.

10. The regulator of claim 9 wherein said adjustment mechanism requires a specific tool for adjustment.

11. The regulator of claim 9 comprising a protective cover for said access opening to D provide an indication that said adjustment mechanism has been accessed after said protective cover was installed.

12. A pressure regulator, comprising: a regulator body, an adjustment means for adjusting the pressure setting of the regulator; and a cover for said adjustment means; said cover being installed on said body; said cover and said adjustment means being mechanically coupled so that repositioning said cover causes a change in the regulator pressure setting.

13. The regulator of claim 12 wherein said cover is threadably installed on said body, and said adjustment means is threadably coupled with said cover, so that rotation of said cover causes repositioning of said adjustment means.

14. The regulator of claim 13 wherein said adjustment means comprises a threaded disk.

15. The regulator of claim 13 wherein said adjustment means comprises a threaded screw.

16. A method for making a pressure regulator tamper resistant, comprising the steps of: installing a cover on the regulator; mechanically coupling the cover to a pressure adjustment mechanism of the regulator; and adjusting the regulator pressure setting to a desired value, said mechanical coupling causing the adjustment mechanism to change the pressure setting when the cover is repositioned.

17. The method of claim 16 wherein said mechanically coupling step is performed by threadably coupling the cover to the regulator body and the pressure adjustment mechanism.

18. The method of claim 16 wherein said step of adjusting the regulator pressure setting is performed after the cover is installed.

19. The method of claim 16 comprising the step of securely installing the cover on the regulator.

20. The method of claim 16 wherein said step of adjusting the regulator pressure setting is performed by changing compression of a spring in the pressure adjustment mechanism.