How to solve the problem of pump head lift

Axial-flow pumping stations in the Plain Lakes region are usually operated in the event of floods and floods, although some pumping stations are designed to perform checks under certain unfavorable conditions but are affected by changes in the water environment, such as along rivers and lakes. The river bed is highly silted year after year, the internal and external water level of the pump station varies greatly, especially the high water level of the outer river during the catastrophic flood period, making the head of the frequency conversion constant pressure water supply equipment exceed its design and use range, and the pumping station is forced to stop and even damage. . To solve the above problems, we can take measures according to the actual situation of each station.

(1) Adjusting the blade installation angle Currently, the domestic axial pump diameter is more than 300 mm, and the blade angle can be adjusted. Adjusting the installation angle of the blade expands the use scope of the pump to a certain extent. When the lift of the pump station increases, the installation angle of the blade can be reduced, and the amount of water output can be appropriately reduced to meet the requirements of the normal operation of the water pump under high head conditions.

At present, there are a large number of domestically distributed small and medium-sized axial-flow pumping stations (generally managed by townships) with diameters of up to 1 meter. Due to weak technical strength, it is time-consuming and labor-intensive (half-tuned). Therefore, after the pumping station is put into operation, the normal operation range of the pump is seldom checked and adjusted according to changes in the operating conditions. As a result, energy is wasted and the pump station cannot play its normal benefits. Therefore, it is recommended to strengthen technical guidance, especially for those pumping stations that are used improperly and whose lift exceeds the normal range of use. The pump operating conditions should be carefully reviewed according to the new operating conditions, and corresponding technical measures should be proposed. In accordance with the principle of economical and effective use, generally only when the angle adjustment can not meet the new operating requirements, consider the other technology (valve, water pump) transformation program.

(2) Changing the pump If the blade angle is adjusted to the minimum and the long-term operation requirement of the high head cannot be satisfied, you may consider replacing the pump with a high head, such as an axial pump with a lower rotation speed or a diffuser pump with a guide vane.

Replacement of the water pump is usually a relatively easy way. However, for large and medium-sized diesel pumps, factors such as the matching of the unit and the flow channel must be considered. Therefore, the project investment is large, and the cost of the unit equipment is high. In addition, at the same flow rate, due to the high lift of the pump, the possibility of cavitation erosion and hydraulic vibration of the pump is increased, especially the hydraulic coordination problem between the inlet and outlet flow passages often becomes the main contradiction of pump replacement. Therefore, using the method of changing the pump to solve the high lift problem on the basis of the original pump station hydraulics is not only costly but also technically complex, so it is generally only applicable to small and medium-sized axial pump stations. In addition, when pump changing, it is not only necessary to consider that the pumping station can run safely when the highest lift is reached, but also that the average efficiency of the pumping station in years of operation should be as high as possible, and the pumping station with a big difference between the maximum head and the average head should be sufficiently full. Consider this.

(3) The advantages and disadvantages of changing the impeller changing impeller and changing the pump are almost the same. However, changing the impeller involves only one part of the pump, so the investment in retrofitting can save a lot, and it is usually suitable for the repair and technical renovation of large and medium-sized axial-flow pumping stations.