Pneumatic act. 2

[adrenalin]

Hi everyone,
One of my client has a pneumatic actuator on his DN500 ball valve. The valve is assembled on a natural gas line.
My client wants to use the line pressure to actuate the valve. I already told him about the the pressure reduction needed. Do you have any other comments on this?
Have you heard similar applications before as it is kinda new to me?
Thanks in advance...

 

[JLSeagull]

A few companies such as Shafer make double acting vane actuators coupled with gas over oil hydraulic supplies. These are common in gas pipeline applications.

 

[terje61]

Hello Adrenalin,

Make sure that you install an overpressure relief valve after the pressure regulator. You do not want to blow-up your actuator, when someone re-adjusts the regulator.

Make sure that you use dry natural gas, otherwise install a dryer. Most actuator internals will corrode in wet natural gas.

Check if the instrumentation your client is using is natural gas compatible. Especially the explosion proof certification is often not valid when using natural gas.

Also small equipement internals might have problems with deposits from the natural gas. This is often seen in I/P converters or in positioners. Sometimes a 'cleanroom' filter helps.

Finally you have to do something with all the exhaust gas, tube it to a vent, flare or low-pressure gas line. Make sure that this is a large diameter exhaust line, because you do not want any pressure built-up while stroking. Back-pressure will interfere with the functioning of the positioner.

Good luck,
Terje

 

[dcasto]

wellhead auto hi/lo shutin systems do it all the time. Check out some wellhead hi/lo shutin suppliers.

I used axelson with versa valves some times.

 

[adrenalin]

thanks for your help.
especially, terje61, for the complete approach!
Regards