Suction pipe. Hot condensate.
Suction pipe. Hot condensate.
(OP)
Hi!
I really need some tips, or comments, of a pump/ piping problem!
Hot/ boiling water (condensated steam) from a vessel will be pumped.
-The level difference between the pump, suction, and vessel is app 5,5 m (18 feet)
-NPSHr for the pump is 3 m (10 feet).
-The suction line is app 40 m (133 feet) long. With some bend and one valve, pressure drop is app 0,7 m (2,3 feet).
-The “lowest” pressure in the suction pipe is 2,3 m (7,63 feet). Before it goes down to the pump level another 3 m (10 feet) down.
Are there any risk for vapour bubbles in the suction pipe when the “lowest” pressure only is 2,3 m (7,63 feet) (water)?
What is the recommended max velocity for hot condensate?
Is NPHSa- NPSHr= 1,6 m (5,3 feet) enough?
Many Thanks Erik (new on Eng tips)
I really need some tips, or comments, of a pump/ piping problem!
Hot/ boiling water (condensated steam) from a vessel will be pumped.
-The level difference between the pump, suction, and vessel is app 5,5 m (18 feet)
-NPSHr for the pump is 3 m (10 feet).
-The suction line is app 40 m (133 feet) long. With some bend and one valve, pressure drop is app 0,7 m (2,3 feet).
-The “lowest” pressure in the suction pipe is 2,3 m (7,63 feet). Before it goes down to the pump level another 3 m (10 feet) down.
Are there any risk for vapour bubbles in the suction pipe when the “lowest” pressure only is 2,3 m (7,63 feet) (water)?
What is the recommended max velocity for hot condensate?
Is NPHSa- NPSHr= 1,6 m (5,3 feet) enough?
Many Thanks Erik (new on Eng tips)





RE: Suction pipe. Hot condensate.
Regards checman
RE: Suction pipe. Hot condensate.
Your piping sounds like it must have quite a bit of horizontal runs in it, which is a no-no for saturated fluids. There is the risk of vapor pockets in horizontal runs.
For me and for systems that I design for hot condensate, I try to never exceed 2 m/sec. That may be on the conservative side, but it has always served me well.
rmw
RE: Suction pipe. Hot condensate.
The water velocity in the suction pipe is 0,75 m/s (2, 48 feet/s). Pipe diameter is 300 mm (11,8 in).
It is correct that there is a long horizontal part. The lowest pressure in this horizontal part is app 2,3 m (water column ). Im most worried for vapour in this part.
Best regards Erik
RE: Suction pipe. Hot condensate.
http://www.bellgossett.com/Press/NPSH2.html