What does \"pressure control valve and temperature interlock\" mean?
Thread Content
Liquid nitrogen passes through the vaporizer and then reaches the pressure control valve; why is there a linkage with temperature after the pressure control valve?
I speculate that when the temperature is low, liquid nitrogen vaporizes more slowly, resulting in lower pressure in the rear section for a short period of time; a large amount of liquid nitrogen enters the low-pressure tank at the back, which under certain conditions can lead to a rapid increase in pressure there.
Regardless of the type of valve, its function in this interlock system is merely to cut off flow; the valve closes as a result of low temperatures. This approach is feasible, but it’s likely that the temperature of the equipment/process downstream is too low
The pressure control system at the top of the nitrogen tank ensures the proper operation of this system. When there is a malfunction in the liquid nitrogen vaporizer, if the temperature of the nitrogen gas behind the pressure control valve falls below the set value, the valve is shut off automatically to prevent liquid nitrogen, or nitrogen gas at extremely low temperatures, from entering the nitrogen tank, thereby avoiding accidents in the tank.
It’s just a dual-system common control valve.
This is a solenoid valve, right? It is a valve used for both DCS system control and SIS shutdown, with the SIS commands taking priority. The actuator, which is normally used to adjust the PIC, triggers a interlock in case of high or low pressure in the feed line, resulting in an emergency shutdown.
Pressure is definitely related to the bubble point temperature!
I understand it’s regulated by a DCS system. I can also understand what thermocouples, electric valves, DCS indications, alarms, and interlocks mean. But what is SIS? “Thermocouples and electric valves, DCS indications, alarms, interlocks” – this is part of SIS. Does SIS take precedence over DCS?
Controlling the temperature is done with a temperature sensor; when the temperature is high, the expansion valve closes
PID control is carried out when the temperature is normal; an alarm is issued when the temperature falls below the set value. When the temperature is extremely low, the PV control valve is closed to protect subsequent equipment.