During the operation of High Pressure Online Circulation Pump, there are mainly the following ways to adjust flow:
1. Frequency conversion speed regulation
Frequency conversion speed regulation is a common and accurate flow adjustment method. Adjust the pump speed by changing the power supply frequency of the motor. According to the similarity law of pumps, the flow rate of the pump is approximately proportional to the rotation speed. When the frequency is reduced, the motor speed decreases and the pump impeller rotates slower, thereby reducing the flow rate; conversely, increasing the frequency will increase the flow rate.
The advantage of this adjustment method is that it has significant energy saving effect. During partial load operation, the flow rate can be accurately adjusted according to actual needs, avoiding the energy loss caused by valve throttling in the traditional throttling adjustment method. Moreover, variable frequency speed regulation can achieve smooth flow adjustment with less pressure impact on the system, helping to extend the service life of pumps and pipeline systems.
2. Outlet valve adjustment
The flow is controlled by adjusting the valve opening on the pump outlet pipeline. When the valve opening decreases, the resistance of the piping system increases. According to the pump performance curve, the pump's operating point will move to the upper left along the head-flow curve, thereby reducing the flow rate. On the contrary, increasing the valve opening will reduce the pipeline resistance and increase the flow rate.
However, this adjustment method has certain shortcomings. Due to the valve throttling, energy loss will occur, especially in the large flow adjustment range, the energy loss is more obvious. Moreover, excessive throttling may cause pump cavitation, adversely affecting pump performance and life.
3. Bypass adjustment
Set up a bypass pipeline and install a regulating valve on the bypass pipeline. Part of the fluid is returned to the inlet of the pump via a bypass, thereby reducing the flow through the main pipe. This adjustment method is more practical in some simple circulation systems, but it will also cause a certain amount of energy loss due to the throttling of the bypass valve.
In addition, for some more advanced High Pressure Online Circulation Pumps, the flow rate can also be adjusted by changing the diameter or number of stages of the impeller. However, this method usually requires structural modification of the pump, which is costly and is generally used during the design and selection stage of the pump or under special circumstances. In practical applications, it is necessary to comprehensively consider system requirements, energy-saving effects, adjustment accuracy and other factors to select an appropriate flow adjustment method.
