Why does the outlet pressure drop after a centrifugal pump has been running for a long time?
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Previously, the outlet pressure of the pump was 2.1–2.2 MPa; after operating for a long time, it dropped to 1.7–1.8 MPa? The imported filter screen is also cleaned once a week, and the current level is normal.
Factors affecting the pump outlet pressure: 1, inlet pressure; 2, outlet backpressure; 3, rotational speed; 4, flow rate; 5, fluid short-circuiting within the pump. Based on the symptoms you described, it’s unlikely to be the first three factors. It’s possible that an increase in shaft displacement within the pump has led to an increased gap, causing the fluid at the outlet to flow back toward the inlet. . . For reference only.
1. Check the inlet pressure. 2. Check the outlet flow rate. 3. Check the impeller condition
Generally, wear at the mouth ring is the first thing that is suspected~~~ But for shielded pumps, investigation can start from the following aspects~~~ If the temperature of the medium is higher than normal, the backflow of the vapor phase line at the top of the pump (for small pumps,~~~ on the motor side of large horizontal pumps) will increase； Additionally, it can assist in checking changes in the operating conditions of the device’s vapor reflux tank~~~~
The inlet pressure is normal, the impeller is in good condition, and the outlet flow rate is basically normal