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[npparab12]

PSV Sizing for Progressive Cavity pump.

 

Operating Flow rate is 65.3 m3/hr at Selected RPM of 265

Flowrate at Max. pump speed (300rpm) Ex area = 75m3/hr. as per pump curve.

Pump Design is for 400rpm with flowrate of 120m3/hr.

 

1. I have received the Vendor Doc for PSV Sizing Calc for 120m3/hr. 

My question is if we have selected the Pump to work with maximum speed of 300rpm & 75m3/hr then PSV should be sized for 75m3/hr. This will be the worst cases scenerio for pump Right / Wrong ? sizing for 120m3/hr will never be the case.

 

2. The PSV Orifice Size Calculated is 3.49 sqinch. But Vendor has selected Q with 12.91 sq.inch. Stating a reason as, 'Oversize due to 6" inlet connection and 8" outlet connection. Acceptable for the requested flowrate.'

Usually we select PSV one size higher and then Size the Inlet /Outlet Line base on pressure drop and MACh no. 

 

Request for guidance.

 

 

 

 

 

  

[latexman]

How is speed controlled?

 

 

 

Usually we select PSV one size higher and then Size the Inlet /Outlet Line base on pressure drop and MACh no. 

Mach number, in liquid service?