What to do when a D-type horizontal multistage centrifugal pump experiences negative pressure

Category: Water pump knowledge

2025-07-14

When a D-type horizontal multistage centrifugal pump experiences negative pressure, it means the pressure inside the pump is lower than atmospheric pressure. This can lead to decreased pump efficiency and performance, or even other problems. Here are several methods for handling negative pressure in a D-type horizontal multistage centrifugal pump.

1. Check Seal Performance: First, check the sealing performance of the pump and its piping system. Any leaks can cause negative pressure. If sealing problems are found, the seals should be replaced or repaired promptly.

2. Adjust the Inlet Valve: Open the inlet valve appropriately to increase the pump's inlet flow. This helps balance the pressure inside and outside the pump, thus eliminating negative pressure.

3. Check the Pump's Installation Position: Ensure the pump's installation position meets design requirements. If the pump is installed too high, it may cause insufficient inlet pressure to the pump, resulting in negative pressure. In this case, consider lowering the pump's installation height or increasing the length of the inlet pipe.

4. Check the Pump's Speed: Ensure the pump's speed is within the normal operating range. Speeds that are too high or too low can cause unstable pump flow and pressure, resulting in negative pressure. If necessary, adjust the pump's speed.

5. Clean or Replace the Filter: If a filter is installed at the pump's inlet, check if the filter is clogged. If the filter is clogged, it will cause insufficient inlet flow to the pump, resulting in negative pressure. Cleaning or replacing the filter can solve the problem.

6. Check the Piping System: Check the piping system for air accumulation or blockages. If necessary, air should be vented from the pipes or blockages cleared.

7. Increase Backpressure: In some cases, negative pressure can be eliminated by increasing backpressure. This can be achieved by installing a backpressure valve or using other methods.

8. Seek Professional Help: If the above methods fail to solve the problem, it is recommended to contact a professional pump repair service provider or the manufacturer's technical support team for more professional guidance and advice.

In summary, handling negative pressure in a D-type horizontal multistage centrifugal pump requires consideration of multiple factors. By checking seal performance, adjusting valves, checking installation position, checking speed, cleaning or replacing filters, checking the piping system, and increasing backpressure, problems can usually be effectively solved. If the problem is complex, it is recommended to seek professional help.

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