The flow rate of the pump, that is, the amount of water output, should not be selected too much, otherwise it will increase the cost of purchasing the pump. It should be selected according to demand, such as the self-priming pump used by the user's home, the flow rate should be as small as possible, and the submersible pump used by the user for irrigation can be appropriately selected with a larger flow rate.
1. Pumps should be purchased according to local conditions. There are 3 types of commonly used agricultural water pumps, namely centrifugal pumps, axial flow pumps and mixed-flow pumps. The head of the centrifugal pump is high, but the water output is not large, which is suitable for mountainous areas and well irrigation areas; the axial flow pump has a large water output, but the head is not too high, and it is suitable for use in plain areas; the water output and head of the mixed-flow pump are between the centrifugal pump and the axial flow pump, which is suitable for use in plain and hilly areas. Users should purchase according to the terrain conditions, water source and water lifting height.
2. The water pump should be appropriately exceeded. After determining the type of water pump, it is necessary to consider its economic performance, especially to pay attention to the selection of the head and flow rate of the pump and its supporting power. It must be noted that there is a difference between the head indicated on the pump label (total head) and the outlet head (actual head) at the time of use, due to the loss of resistance when the water flows through the pipes and near the pipeline. Therefore, the actual head is generally 10%-20% lower than the total head, and the water output is also reduced accordingly. Therefore, when actually used, only according to the head and flow rate of the sign 80% ~ 90% estimated, the choice of the power of the water pump, can be selected according to the power indicated on the sign, in order to make the pump start quickly and use safely, the power of the power machine can also be slightly greater than the power required by the water pump, generally higher than about 10% is appropriate;
3. Strict procedures should be used to purchase water pumps. When purchasing, it is necessary to verify the "three certificates", that is, the agricultural machinery promotion license, the production license and the product inspection certificate, only the three certificates can avoid the purchase of obsolete products and inferior products.