3 replies to this topic

[Chemitofreak]

Hi,

 

What is the criteria for selection of Automatic Recirculation Valve (over normal control valve) in pump minimum recirculation line. 

 

Thanks in advance.

[cea]

ARV or auto recirculation valve is used to ensure minimum circulation flow in pump circuit.

 

As name implies, it automatically ensures minimum recirculation flow, by diverting flow towards circulation line, if pump discharge flow reduces to value lower than minimum desired. Unlike control valve, it does not require flow / pressure transmitter to activate its operation.

 

You may google about construction & operation of ARV, which is self-explanatory.

 

Although ARVs are comparatively reliable, it has been observed that is not preferred choice, especially in refinery operation, wherein pump flows are huge & malfunction of ARV (in case) becomes costly affair.

Edited by cea, 20 April 2016 - 11:16 PM.

[fallah]

 

What is the criteria for selection of Automatic Recirculation Valve (over normal control valve) in pump minimum recirculation line. 

 

 

Chemitofreak,

 

The criteria for selection of ARC valve over normal CV+FE:

 

1) In minimum flow recirculation line not higher than almost 8" due to the high cost in larger size...

 

2) In clean service due to potential for plugging... 

 

3) When fine adjustment of minimum flow isn't required because they are not so accurate...

 

4) When the pump curve isn't so flat near the shut off...

 

5) When due to safety issues or high expense of the pump (such as BFW pumps) there should be no dependence to the plant control system, because the ARC valve is fully mechanical
 

[Chemitofreak]

Thanks a lot Naser for your prompt reply.