Problems with the suction pipe before the pump
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I would appreciate it if an expert could advise me: what problems can occur if the suction pipeline in front of the pump is too long?
The pipeline losses are high; if the device does not have sufficient net positive suction head, it is prone to cause cavitation in the pump
Is it unrelated to the net positive suction head? It seems that cavitation will still occur.
An excessively long suction pipe in front of the pump results in significant head losses; when the pressure head available in the system is insufficient and the pump’s net positive suction head is low, cavitation occurs
This post was last edited by 3983596_FPPZ on 2019-8-4 at 12:11. Any structure that increases resistance in the pump inlet pipeline should be avoided as much as possible: such as very long inlet pipes, very thin inlet pipes, sudden changes in the diameter of the inlet pipe, too many inlet valves, too many inlet elbows, valves and testing instruments with excessive resistance, and inlet filters with too large mesh sizes. All of these factors reduce the NPSHA of the system. When the NPSHA of the system drops to a level close to the NPSHR of the pump, it is easy for cavitation to occur in the pump.
If the pump inlet pipe is too long, pressure is lost in the pipes. When the pressure at the point inside the pump casing that corresponds to the lowest pressure near the impeller drops below the saturated vapor pressure of the medium, cavitation occurs at that location.
If the suction pipe is too long, the pipe resistance increases, which reduces the net positive suction head available (NPSHa) of the device; if this value drops to NPSHr, cavitation will occur.
If the inlet pipe is too long, there will be certain pressure losses in the pipeline due to that
Cannot draw in water; cavitation occurs~~~