2 replies to this topic

[omnibus]

Is there any equivalent length criteria for considering the pressure drop due to a length of expansion bellows in the suction pipeline of sea water pump?
Thanks in advance

[Art Montemayor]

Omnibus:

I find it difficult to envision an expansion joint in the suction side of a seawater pump. Can you furnish a sketch?

Normally, pumping seawater is not an experience to look forward to from an operating point of view. It is dirty, fouling, corrosive, and mainly a pain in the neck to maintain and operate. For that reason, whenever anyone needs or requires to pump seawater, a centrifugal pump is selected and it is placed as close to the seawater level (preferably below it) as possible. The reason(s) for this is that one wants to have as positive an available NPSH as one can. The usual selection on an offshore platform, for example, is a vertical turbine design that is inherently submersible - i.e., it has its electric motor drive at the bottom of the pump. Please refer to the attached typical drawing of such a pump.

If you have a land-based, horizontal centrifugal pump, why would you employ an expansion bellows joint in the suction? What are the materials of construction? Who fabricated the bellows? Does the bellows have a smooth, Teflon (or other material of construction) tube inside the bellows to avoid any undue pressure drop due to resistance and turbulence caused by the bellows?
 Seawater_Lift_Pump.zip   2.19MB   109 downloads

[ankur2061]

Is there any equivalent length criteria for considering the pressure drop due to a length of expansion bellows in the suction pipeline of sea water pump?
Thanks in advance

Omnibus,

Please see the below link for pressure drop in expansion bellows. You can contact the supplier for your desired data.

http://www.metraflex.com/crvflex.php


Regards,
Ankur.