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1. (WO2019048850) TEST DE COURSE PARTIELLE POUR ACTIONNEUR DE SOUPAPE PNEUMATIQUE
Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

CLAIMS

1. A valve actuator for positional control of a valve, the actuator comprising: an actuation piston comprising:

a housing;

a piston;

a first fluid chamber defined between a first end of the housing and a first face of the piston; and,

a second fluid chamber defined between a second end of the housing and a second face of the piston;

a first fluid control valve for supplying pressurised fluid to the first fluid chamber; a second fluid control valve for supplying pressurised fluid to the second fluid chamber; and

a controller adapted to control the first and second fluid control valves to supply fluid to the first and second chambers;

and wherein:

the controller is configured to include a partial stroke test mode, in which the valve actuator is actuated to a predetermined partial position corresponding to a predetermined partial stroke position of a valve to verify performance of the valve,

and in which:

the first chamber is supplied with fluid at a first positive pressure;

the second chamber is supplied with fluid at a second positive pressure;

and wherein:

controller relatively varies the first and second pressures to actively control the differential pressure across the piston.

2. A valve actuator as claimed in claim 1, wherein during a partial stroke test, the controller fixes the first pressure in the first chamber, and varies the second pressure in the second chamber, to provide a required differential pressure.

3. A valve actuator as claimed in claim 2, wherein the required differential pressure relates to the predetermined partial stroke position of the valve.

4. A valve actuator as claimed in any preceding claim, wherein the controller controls the pressure differential between the first chamber and second chamber to provide a pressure corresponding to the required valve actuator position.

5. A valve actuator as claimed in any preceding claim, wherein the controller adjusts the second pressure in response to the pressure in the first chamber and the movement of the actuator.

6. A valve actuator as claimed in any preceding claim, wherein the controller actively adjusts the second pressure during the partial stroke test mode.

7. A valve actuator as claimed in any preceding claim, wherein the controller detects stiction during partial stroke testing and actuates the second fluid control valve to apply a second positive pressure to the second chamber.

8. A valve actuator as claimed in any preceding claim, wherein the valve is a quarter turn valve.

9. A valve actuator as claimed in any preceding claim, wherein the valve is an industrial valve.

10. A valve actuator as claimed in any preceding claim, wherein the valve is an emergency shut down valve.

11. A valve actuator as claimed in any preceding claim, wherein the valve actuator further comprises a spring against which the piston acts.

12. A valve actuator as claimed in any preceding claim, wherein the valve actuator is a substantially zero bleed valve.

13. A valve actuator as claimed in any preceding claim, wherein the actuator is an actuator for high integrity emergency shutdown valves.

14. A valve actuator as claimed in any preceding claim, wherein the actuator is a pneumatic actuator.

15. A valve actuator as claimed in any one of claim 1 to claim 13, wherein the actuator is a hydraulic actuator.

16. A valve actuator as claimed in any preceding claim, wherein the controller comprises a screen, such as an organic light emitting diode (OLED) screen, which locally displays real-time data regarding the partial stroke test.

17. A valve actuator as claimed in claim 16, wherein the actuator and/or controller further comprises a memory to store the real-time data for each partial stroke test.

18. A valve actuator as claimed in any preceding claim, wherein the valve actuator further comprises at least one low power and high-speed solenoid valve.

19. A valve actuator as claimed in any preceding claim, wherein the valve actuator further comprises integrated filter boosters.

20. A valve actuator as claimed in any preceding claim, wherein the valve actuator is retrofittable into existing systems.

21. A method of partial stroke testing a valve actuator, the method comprising actuating a valve actuator to a predetermined partial position corresponding to a predetermined partial stroke position of a valve to verify performance of the valve/actuator.

22. A method as claimed in claim 21, wherein the method further comprises: supplying a first chamber with fluid at a first positive pressure;

supplying a second chamber with fluid at a second positive pressure; and

varying the first and second pressures to control the differential pressure across the piston.

23. A method as claimed in claim 22, wherein the method further comprises fixing the first chamber pressure and varying the second chamber pressure to provide the required partial pressure.