Requirements for selection of deep well pumps
Deep well pump selection requirements:
1. Initially determine the pump type according to the well diameter and water quality. Different types of pumps have certain requirements for the diameter of the well hole, and the maximum external dimension of the pump should be less than 25-50mm in the well diameter. If the borehole is skewed, the maximum size of the pump should be smaller. In short, the pump body cannot be close to the inner wall of the well to prevent pump vibration from damaging the well.
2. According to the water output of the well, select the flow rate of the deep well pump. Each well has an economically optimal water output, and the flow rate of the pump should be equal to or less than the water output when the water level of the pumped well drops to half the depth of the well. When the pumping volume is greater than the pumped well, it will cause the wall of the pumped shaft to collapse and deposit, which will affect the life of the well; if the pumping volume is too small, the benefits of the well will not be fully utilized. Therefore, the best way is to carry out pumping tests on pumped wells, and the pump flow rate of the well is selected based on the maximum possible water output of the well. The pump flow rate is subject to the manufacturer's model or the number marked on the manual.
3. Determine the actual required head of the deep well pump according to the depth of the well water level drop and the head loss of the water delivery pipeline, that is, the head of the deep well pump, which is equal to the vertical distance from the water level to the water surface of the outlet pool (net head) plus the loss head. The loss head is usually 6-9% of the net head, generally 1~2m. The water entry depth of the bottom stage impeller of the pump is preferably 1~1.5m. The total length of the downhole part of the pump tube should not exceed the maximum length of entry into the well specified in the pump manual.
4. Pumped wells with sand content of well water exceeding one ten thousandths should not be installed with deep well pumps. Because the sand content of the well water is too large, if it exceeds 0.1%, it will accelerate the wear of the rubber bearings, cause the pump to vibrate, and shorten the pump life.
