Can anyone tell me about single block and bleed ball valve?

What is the main functional difference between a pneumatic diaphragm actuator & a pneumatic piston actuator while operatin a globe valve.Will it be difficult to attain the precise control with piston

Can anyone suggest a quick valve manufacturer of E series valve 8" 300# C/S Ebonite liner?

I have two questions :For buried application , is it OK to use Rising stem gate valve ??

A potential problem in one of our quick close valves was brought to my attention. During normal operation, the actuator to the main valve is held closed by an 80 psi instrument air line.

Can anyone tell me why chromium plated ball valves may not be acceptable in a refining environment?

What is the main reason to use Y-pattern globe valves?

I am trying to determine the actuator torque required for my metal seated, eccentric (meaning offset) butterfly damper.