What are the methods for adjusting the flow rate of a water pump?

What are the methods to adjust the flow of a pump?

If the operating point of a centrifugal pump is not within the high-efficiency range during operation, or if the pump's flow rate and head do not meet the requirements, the operating point can be adjusted by changing the pump's performance, adjusting the required head curve, or both. This method is known as pump operating point adjustment. Common adjustment methods include variable speed regulation, variable diameter regulation, variable angle regulation, and throttling regulation, among others.

One: Variable Diameter Adjustment

After the impeller has been turned, the performance of the pump will change according to a certain规律, thereby altering the operating point of the pump. We refer to the method of changing the operating point of the pump by turning the impeller as diameter regulation.

Streamline and Adjust

For pump units with check valves installed in the discharge pipeline, when the check valve is partially closed, it increases local resistance in the pipeline, causing the pipeline characteristic curve to steepen. The operating point then moves upwards and to the left along the pump's Q-H curve. The smaller the check valve is closed, the greater the resistance added, and the smaller the flow becomes. This method of changing the pump operating point by partially closing the check valve is known as throttling regulation or variable valve regulation.

Closing the throttle valve increases the local head loss in the pipeline, shifting the system characteristic curve to the upper left. The operating point of the pump also moves to the upper left. The smaller the throttle valve is closed, the greater the local head loss, and the lower the flow rate. It is evident that throttling regulation not only increases local head loss but also reduces the output flow, which is economically inefficient. However, due to its simplicity and ease of use, it is widely applied in small pump installations and pump performance tests.

III. Variable Angle Adjustment

Adjusting the installation angle of the blades can alter the performance of the pump, thereby changing the operating point of the pump. This method of changing the operating point is known as the variable-angle adjustment of the pump.

Four: Gear Adjustment

Adjusting the pump's speed can alter the pump's performance, thereby changing the operating point of the pump, a method known as variable speed regulation.