What are the points to note when operating a mixed-flow pump? How should it be maintained?

Because the impeller of a mixed-flow pump is close to the middle of the centrifugal pump impeller and the mixed-flow pump impeller, the principle of the mixed-flow pump not only has centripetal force but also lift. Under the combined action of the two, the water is discharged from the impeller at a certain angle to the shaft, and is lifted to a high altitude according to the volute and pipeline.

　　Compared with centrifugal pumps, mixed-flow pumps have lower head and larger total flow. Compared with mixed-flow pumps, centrifugal pumps have higher head and smaller total flow. The characteristic curve of a mixed-flow pump is also close to the middle of a centrifugal pump and a mixed-flow pump. For high-head mixed-flow pumps, the intrinsic relationship between total flow, pump head, total flow, and output power is close to that of centrifugal pumps. In application, the gate valve can be closed for operation.

　　The following points must be noted when operating a mixed-flow pump:

　　1. Whether the impeller is sufficiently submerged, that is, whether the intake pipe is too low, to prevent endangering the total flow or causing noise.

　　2. Whether the impeller edge and impeller casing are damaged, whether the blades are covered with dirt, and whether the vulcanized rubber or plastic bearings are too tight or burnt out.

　　3. Whether the foundation bolts are loose, and whether the pump shaft and the rotating shaft management center are consistent.

　　Maintenance of mixed-flow pumps:

　　1) When lubricating rolling bearings with thin oil, regularly check the oil type between the two road markings to operate the rolling bearing body; when lubricating rolling bearings with grease, add the remaining oil in time. For 100~350 HW pumps, remove the front and rear covers to add oil; for 400~650 HW pumps, add oil according to the oil standard.

　　2) Regularly check the temperature rise of the rolling bearings. The general operating temperature should not be higher than 40℃, and the high temperature should not exceed 80℃.

　　3) Pay attention to whether there are any friction and knocking sounds during pump operation. If the pump cover rubs against the impeller, you can lift the gasket between the pump cover and the pump casing. The specific application gap is 0.3~0.7 mm.

　　4) The adjustment of the packing must be moderate, and the liquid state needs to be interrupted and dropped from the packing nut to be exposed. If the packing is too tight, the shaft will become hot, and the output power will increase; if the packing is loose, too much liquid will leak, and the efficiency will decrease.

　　5) If the motor is directly connected to the pump, the pivots of the two shafts should be on the same parallel line.

　　6) Check for steam leaks in the intake pipe.

　　7) Pay attention to whether the output power suddenly increases or decreases, and whether the total flow suddenly decreases. If so, stop and clean it.

　　8) Regularly check whether the bolts around the feet are loose due to vibration.

　　9) After winter shutdown, the operating water in the pump and pipeline should be drained.

　　10) After the pump has been used for 200 hours or half a year, the grease should be replaced. After that, change the oil every 1000 hours or one year.

11) After the pump has been operating for 3000 hours or three years, the pump should be disassembled for regular inspection and maintenance. 12) For pumps that are not used for a long time, after rust prevention treatment, some parts should be disassembled and stored properly.

If you have any other questions about mixed-flow pumps, please contact us. We are a manufacturer of mixed-flow pumps. We have a very detailed understanding of mixed-flow pumps.