static head
static head
(OP)
I'm sizing an centrifugal pump for a water service in a close system. The system starts from the surge tank, pump, few heat exchangers and complex piping network. Eventually the pump discharge comes back and joins the pump suction. The surge tank is 30 ft elevated and is the highest point in the system. The second highest point in the system is the bank of heat exchangers where the pump discharges.
1) I've calculated the discharge pressure by taking a static head of 15 ft. 15 ft is the height from the grade to the highest inlet nozzle of the heat exchangers.
2) Then I've added dynamic losses, control valve losses, filter pressure drop etc to arrive at a total discharge pressure.
A counter argument is: Since the pump discharge comes back and joins the suction in a closed loop system. The static head is irrelevant and should not be included in the sizing calculations. Risk of not adding the static head means the pump will be undersized.
Please commnent and share your thougths.
Thanks in advance
John
1) I've calculated the discharge pressure by taking a static head of 15 ft. 15 ft is the height from the grade to the highest inlet nozzle of the heat exchangers.
2) Then I've added dynamic losses, control valve losses, filter pressure drop etc to arrive at a total discharge pressure.
A counter argument is: Since the pump discharge comes back and joins the suction in a closed loop system. The static head is irrelevant and should not be included in the sizing calculations. Risk of not adding the static head means the pump will be undersized.
Please commnent and share your thougths.
Thanks in advance
John
Asif Raza





RE: static head
I hate Windowz 8!!!!
RE: static head
What about the start-up conditions?
Thanks
John
Asif Raza
RE: static head
Cheers,
John
RE: static head
that's provided the system can be fully charged from another source, if you need to use the system's pump to fill the loop, then the pump must be capable of generating sufficient head to reach the high point, this can be at a much reduced flow rate but it must be capable of pumping to the static head.
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: static head
RE: static head
Thanks
John
Asif Raza
RE: static head
Correct.
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: static head
Good discussion..
Asif Raza