Can a control valve be connected to both a thermometer and a pressure gauge?
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The control valve is located in the feed pipeline and is used to adjust the feed volume based on the temperature of the reactor; if the pressure in the reactor becomes too high, the control valve must be closed
It can be connected; temperature is used as the signal for the control valve to regulate normally, while pressure serves as the interlock condition to force the valve to close!
The owner also mentioned it in the same way. . But something seems off; in the past, what I encountered were always combinations of control valve assemblies and shut-off valves
Regulating valves with quick cut-off function can be used, with temperature and pressure being controlled in conjunction
It would be best to add a shut-off valve as well; although it is logically possible to do so, the sealing performance of the control valve itself is not good enough
This DCS is easy to implement; as long as the sealing of the control valves is proper, a PID control system can be used for temperature regulation, and an interlock can be set up for the valves controlling pressure. It’s a very simple setup.
It should be noted that this function works without any problems. The owner might be considering costs, or perhaps the requirements in terms of technology aren’t very high! For higher requirements, a dedicated shut-off valve must be installed!
It is best for the control valve to be equipped with an emergency shut-off solenoid valve, so that the valve can be adjusted properly based on the temperature signal； When the pressure reaches the interlock value, the solenoid valve loses power, the valve closes, the control circuit is switched to manual mode, and the control signal output becomes zero!
It’s possible; what was said above makes sense, and a synthesis of those points will suffice. However, it is necessary to consider whether the overpressure that occurs when the control valve does not close properly falls within safe limits.