All solenoid valves normally closed, open with electrical current. All pneumatic operated valves, normally closed (by spring) opens by air. Failsafe all: closed (by no air and/or no current).

What is the SIL requirement or reliability objective? Are you trying to avoid a nuisance trip due to a solenoid coil failure; or absolutely trip if required?

The pid-loop output to control my recip-compressor's loading solenoid valves, for example:

We specified solenoid valves for our ON/off valves to work with 120 VAC. Some of these solenoid valves must operate in a classified area and require to be intrinsically safe.

See API 520 Part II helps the design guide for venting two safety relief valves into one common vent pipe..

CCI parts are expensive, So are the other name-brand valve company's parts. That's because the manufacturer has to develop the part, maintain engineering records, material controls,ISO9000 programs,

Pipelines still present a lot of hand operated valves. Did anyone solve this extenuating and tyring hand operation by a sort of practical "power kit"?

To test valves in his fabricated steam pipeline to the standards of ASME B31.3 2006; 345.2.2. The customer is ignoring the testing standards of API-598, ASME B16.34, MSSP-61 and API-6D.