| 摘要 |
<p>A system for protecting piping downstream of a wellhead includes an inlet connected to the wellhead and an outlet connected to downstream piping. Two sets of series-connected surface safety valves are in a parallel fluid flow relation to each other and in fluid communication with the inlet. Two vent control valves, which are in fluid communication with each other, each of the two series-connected safety valves and the inlet and outlet of the system, are intermediately connected to the safety valves. Each vent control valve is in fluid communication with a vent line for venting process pressure between surface safety valves through the outlet control valve based on a signal-generating safety logic solver having preprogrammed safety and operational protocols and pressure sensing transmitters attached upstream of the outlet control valve Independent, tight shut-off tests of each series-connected surface safety valve set closes all valves upon electrical or hydraulic failure.</p> |
