There are several modes of failure for a BFW leak off valve. They can fail due to seat leakage casuing micro cavitation whilst in the shut position.

I once installed a 12-inch gate valve in a valve-can on a gathering system. The valve takes almost 100 turns to operate

I am investigating alternatives, one is to use DC solenoid valves - but the need for a large DC power supply may not be cost effective, also robustness is an issue.

Fusible link actuator to be installed on 3" and 4" groves class 600 or if they have the complete valve +actuator that will be considered too, one feature I'm looking for is the ability to override the

Closeoff is how much differential pressure the valve / actuator combination can overcome in order to seat the valve and stop flow completely.

The valves, of course, would be cleaned and degreased, and we are talking about industrial O2 services, not breathable O2.

I am interested in the use of grease as sealant in high pressure (60 bar / 900 psi) gas valves with diameter 4

The equation Q=Cv sqrt(dp/G) is, in fact derived from the bernoulli eqn.