How do you reduce centrifugal pump discharge pressure?

You can reduce centrifugal pump discharge pressure primarily by altering the pump's operation or impeller characteristics.

Methods to Reduce Discharge Pressure

According to the reference provided, there are two main ways to reduce the discharge pressure of a centrifugal pump:

Reduce the speed of rotation of the pump: Decreasing the rotational speed reduces the energy imparted to the fluid by the impeller, thus lowering the discharge pressure. This can be achieved by reducing the power supplied to the motor driving the pump.
Use a smaller diameter impeller: An impeller with a smaller diameter will impart less energy to the fluid, resulting in a lower discharge pressure.

To elaborate further, consider the following approaches:

Speed Reduction:
- Variable Frequency Drive (VFD): Implementing a VFD allows you to precisely control the motor speed and, consequently, the pump's rotational speed. Reducing the speed directly reduces the pump's head (pressure).
Impeller Modification:
- Impeller Trimming: Machining the existing impeller to a smaller diameter is a cost-effective method. However, this is a permanent change.
- Impeller Replacement: Replacing the existing impeller with one of a smaller diameter is a more involved but reversible approach.

Before implementing any of these changes, it's crucial to understand the system requirements. Reducing the pump's discharge pressure may affect the flow rate and overall system performance.
Always consult with a qualified engineer or pump specialist to ensure that any modifications are suitable for your specific application.