Reduce delay time in opening process valve

[R Mohun]

Hi Engineers
Appreciate your help. I have a hygienic single seat shut off valve with a double acting pneumatic actuator. The valve is normally closed but when it’s opened (energised) It takes about 3-4 seconds for it to open (open feedback). I want to make it open faster.
The valve has aN integrated ‘top’ with feedbacks and also two solenoids (one is normally open and the other normally closed which connects the air to top and bottom of the Valve actuator). When the valve is idle the NO solenoid feeds air to the top of the actuator which along with the spring pressure keeps the vAlve shut. When the valve is energised, the NC solenoid is opened feeding air to the bottom of the actuator opening the valve to overcome the spring pressure. I think the NO solenoid is closed at the same time.
Thanks

 

[LittleInch]

How big a valve?

what type of valve? Ball?, gate?, plug?, control?

Is this a spring closed valve? Your description is quite starange as it's not normal to have a spring and a solenoid acting together.

"Double acting" usually means that the actuator is "fail in position", i.e. it needs air and air alone to move from open to close or close to open.

I think what you have is a spring closed actuator whereto open the NC air supply is open and the NO closed and the piston pushes against the spring. This stays like this until either power failure or command to close when the solenoids revers, the spring closes the valve as the air is let out of the actuator in a controlled manner.

"When the valve is idle the NO solenoid feeds air to the top of the actuator which along with the spring pressure keeps the vAlve shut." - I really don't think this is correct, I think the NO solenoid is the air vent from the cylinder. But a diagram / P&ID would tell you.

Opening speed is dependant on the air supply and any flow or pressure regulators on the air supply. This may be external to the valve but is probably what is controlling the opening speed.

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