Question

Problem 13

f 1144 - + 80% A standard method for instrumenting a control valve is termed the "double block and bleed." which is illustrated in Figure P113. Figure P1.13 Double Block and Bleed Arrangement for Problem 13 globe valve control valve valve valve 13. cteinical sewer laced Answer the

Answer 1

Ans:-

a) first of all changing the stem of control valve (b) in the running process line, bypass valve is open , then the some flow is diverted from bypass when the pressure is qulize, then both isolation valve a & c close, after then drain valve e is open draing the all process fluid . At last contol valve b is close, according to that contol valve issolate and change the stem of contol valve.

b) Inthe process water line no need of bypass valve.

c) For the on off valve only globe of ball valve can used . But in cooling water line you can replace with butterfly valve with globe valve.

d) For the continious running process line bypass valve is important for the maitaing the pressure and flow, if it is stand by line then there is no need of bypass valve.