dual pressure ratings of API pump
dual pressure ratings of API pump
(OP)
can anyone help me with following clause of API-610:
"Unless otherwise specified, vertically suspended, double-casing, integral gear-driven (type OH6) and
horizontal multistage pumps (pumps with three or more stages) may be designed for dual pressure ratings. If
specified, suction regions shall be designed for the same MAWP as the discharge section."
when should we consider this clause? and what it means?
thanks
"Unless otherwise specified, vertically suspended, double-casing, integral gear-driven (type OH6) and
horizontal multistage pumps (pumps with three or more stages) may be designed for dual pressure ratings. If
specified, suction regions shall be designed for the same MAWP as the discharge section."
when should we consider this clause? and what it means?
thanks





RE: dual pressure ratings of API pump
The second point is where there is a chance that the outlet pressure can be seen at the inlet if e.g. a valve fails to close or if the outlet pressure is such that as soon as the pump winds down the pressure can be felt at the inlet.
You could also get this on booster pumps on a pipeline where the initial inlet pressure could be high compared to the steady state pressure.
Why the question?
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RE: dual pressure ratings of API pump
as you mentioned in second point,in worst case, every centrifugal pump could see the shutoff pressure(even if there is minimum flow line in the discharge). so may i conclude that all pumps should be designed for dual pressure?
RE: dual pressure ratings of API pump
Most liquid pumps will be ( or should be) fitted with thermal reliefs on the inlet side to protect against blocked in thermal expansion exceeding the inlet pressure designation
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.