Back pressure regulator operating pressure and bypass with TCV

[uu78hswang]

Dear Sirs

I am sorry to bother your this simple and silly question.
I have a Back pressure regulator and bypass with temperature
control valve, but I don't sure that why this PCV in this bypass
location and how to decide this PCV upstream op?

thank you very much.

 

[gerhardl]

As far as I can see the bypass PCV at B is symbolized as a pilot operated valve, then acting and to be set to maintain (in all probability) a certain pressure upstream (before the valve itself),and to open if this pressure exceeds the set value.

Eg.: the valve will act, if this is the case, as an overflow/pressure mechanical safety valve (the main valve B is motorized), and the purpose is then to maintain the upstream pressure below a selected value, something below the max 7 bar.

Again, if this is the case, the valve will not directly have to do with the temperature regulation under normal conditions, but if the pressure exceeds the set pressure and you get a flow across the valve you will of course also alter the flow (heating/cooling effect) across the cooler, but would also signal 'irregular conditions'.

Others viewpoints ???????