What methods can be used to regulate the flow rate of a slurry pump?

(1) Outlet valve regulation is currently the most commonly used and popular method. A regulating valve is installed on the discharge pipeline of the slurry pump, and the flow rate is adjusted by changing the valve opening. This method is simple and reliable, but it results in significant power loss and poor economic efficiency. It is also ineffective for regulating small or very small flow rates.

(2) Speed regulation, which adjusts flow by changing the rotational speed of the slurry pump impeller. This method has minimal additional power loss and is the most economical approach. However, it requires additional speed-changing mechanisms and motors, resulting in higher initial investment costs. Constant-pressure variable-frequency water supply systems and central air conditioning cooling water circulation systems are two typical examples of variable-frequency speed regulation applied to slurry pump regulation. The method of changing the speed is most suitable for slurry pumps driven by steam turbines, internal combustion engines, and DC motors. Variable frequency regulation can also be used to change the motor speed, and sometimes the speed can be regulated through a hydraulic coupler.

(3) Bypass regulation: This method uses a bypass to divert flow and regulate it, addressing the issue of continuous operation at low flow rates for slurry pumps. However, this results in additional losses due to the diverted flow not being fully utilized, and the process piping also increases accordingly.

(4) Cutting the impeller outer diameter: Adjusting the slurry pump flow rate by cutting the impeller outer diameter results in minimal power loss. However, once the impeller is cut, it cannot be restored, meaning flow rate adjustment is only possible toward lower flow rates. Additionally, the amount of impeller cutting is limited, resulting in a limited flow rate adjustment range. This method is suitable for applications requiring long-term operation at relatively low flow rates with minimal flow rate changes.

(5) Replacing the impeller of the slurry pump: Replacing the impeller with one of a different diameter or outlet width to adjust the flow rate of the slurry pump results in minimal power loss. However, multiple impellers of different diameters must be stocked, and the range of flow rate adjustment is limited.

(6) Blocking part of the impeller flow channel: Reducing the flow rate of the slurry pump by blocking part of the impeller flow channel is equivalent to throttling regulation via an outlet valve. However, this is an active regulation method that reduces additional energy loss, making it more energy-efficient than throttling regulation via a control valve.

(7) Adjust the outlet angle of the blades. Adjusting the outlet angle of the impeller blades to regulate the flow rate of the slurry pump. This method is commonly used in axial flow slurry pumps.

(8) Cavitation regulation. By altering the inlet pressure of the slurry pump to induce cavitation, the characteristic curve of the slurry pump is modified, thereby adjusting its flow rate. Practice has shown that if cavitation regulation is used appropriately, it does not cause severe damage to the flow passage of the slurry pump; on the other hand, it can automatically regulate the flow rate and reduce the power consumption of the slurry pump.

(9) Increasing or decreasing the number of slurry pumps: This method involves adjusting the flow rate of the slurry pump by increasing or decreasing the number of operating slurry pumps, combined with an appropriate merging method.