If the water pressure at the inlet is too high, does it affect the performance of the water pump?
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This post was last edited by Cuaili Yisu on 2018-5-13 at 22:14. A water pump has been purchased, with the requirements being a head of 60 meters and a flow rate of 12 m3/hr; the model chosen is IH50-32-250A, made of 304 material and equipped with a mechanical seal. Now it trips after just two minutes of operation. The inlet water pressure is 1.2M
High inlet pressure leads to an increase in the axial force directed toward the motor. The bearings used in the IH series are deep groove ball bearings, which cannot withstand large axial forces.
Thank you! The details are as follows: A water pump has been purchased, with the requirements being a head of 60 meters and a flow rate of 12 m3/hr. The model chosen is IH50-32-250A, made of 304 material and equipped with a mechanical seal. Now it trips after just two minutes of operation. The inlet water pressure is 1.2 MPaG. When the outlet valve is fully open, the outlet pressure is 1.6 MPaG with a current of 18.5 A; when the outlet valve is closed, the pressure is 2.0 MPaG with a current of 16 A. It’s overloaded; the rated current is 14.7A. The pump manufacturer said that the overload is caused by too high an inlet water pressure, and we didn’t take this factor into consideration when placing the order. Moreover, the pump manufacturer said that the pump casing is designed for a pressure of 1.6 MPa; with such high inlet pressure, there is a risk of the pump exploding, so they asked us to purchase a new one. Is that the reason?
That’s the principle; it’s necessary to control the flow rate and pressure of the inflow.
Does the inlet water pressure have such a significant impact on the performance of water pumps?
The cracking should not be a problem, as pump casings are subjected to hydrostatic testing at a pressure of 1.5 times the operating pressure; therefore, the high inlet pressure in your case needs to be taken into consideration. IH pumps use deep-groove ball bearings in their design, unlike the CZ and Z series, which employ angular contact ball bearings.
Ah, I thought IH and IS were just different in material. The manufacturer says the pump casing is designed for 1.6 MPa – can it be used at 1.8 MPa?
Tripping, overpowering, high inlet pressure – even with back blades, it’s likely that the axial forces are not properly balanced, which leads to excessive current and overpowering. Moreover, ordinary IH water pumps use two deep groove ball bearings that cannot withstand large axial forces, so there are also significant issues with the selection of such pumps
It is not recommended to use it this way; it is better to check the P-T diagram to see the pressure tolerance at various temperatures. High temperatures can reduce the pressure capacity.
If previously the manufacturer was not aware of the import pressure of 1.6 MPa, then the selection was made based on standard centrifugal pumps; in other words, there were no back vanes, no sealing rings on the back side of the vanes, and no verification of axial forces was carried out. If you don’t provide it, then he has a valid point
Does that mean the original pump can no longer be used? Is it necessary to redesign the system with an inlet water pressure of 1.2 MPa?