The flow of the pump, that is, the amount of water, generally should not be selected too large, otherwise it will increase the cost of buying the pump. Should be selected according to need, such as the user family use self-priming pump, flow should be selected as small as possible; If the user irrigation with submersible pump, can be appropriate to choose a few larger flow.
1) to buy water pump according to local conditions. Commonly used agricultural water pump has 3 types, namely centrifugal pump, axial flow pump and mixed flow pump. Centrifugal pump head is higher, but the water output is small, suitable for mountainous areas and well irrigation areas; The axial flow pump has a large amount of water, but the head is not too high, which is suitable for use in plain areas. Mixed flow pump water output and head between centrifugal pump and axial pump, suitable for plain and hilly areas. Users should choose and buy according to the ground conditions, water sources and the height of water.
2) to appropriate exceed the standard water pump. After determining the type of water pump, we should consider its economic performance, especially pay attention to the choice of pump head and flow and its supporting power. It must be noted that the head indicated on the pump sign (total head) and the use of the water head (actual head) is different, this is due to the water flow through the pipeline and near the pipeline will have a certain resistance loss. Therefore, the actual head is generally 10%-20% lower than the total head, and the water yield is reduced accordingly. Therefore, the actual use, only according to the sign injection head and flow of 80% ~ 90% estimate, the choice of water pump supporting power, according to the power marked on the sign, in order to make the pump start quickly and safe use, power machine power can be slightly greater than the required power of the pump, generally 10% higher is appropriate; If there is power, choose and buy a pump, you can choose and buy a matching pump according to the power of the power machine.
3) to strict procedures to purchase water pump. When CHOOSE AND BUY, WANT TO EXAMINE "3 CERTIFICATE", NAMELY AGRICULTURAL MACHINERY PROMOTION PERMIT, PRODUCTION PERMIT AND PRODUCT INSPECTION PASS CERTIFICATE, ONLY 3 CERTIFICATE QI ABILITY AVOIDS TO BUY OBSOLETE PRODUCT AND INFERIOR PRODUCT.
The Numbers to choose
1, to the normal operation of pump, generally only one, because a large pump and parallel operation of two small pump, (the head and flow rate is the same), big pump efficiency is higher than the small pump, therefore, from energy saving point of view would rather choose a large pump, instead of two small pump, but in case any of the following circumstances, can consider two pump parallel cooperation: flow is large, the pump can not reach this traffic.
2, for the need to have 50% of the reserve rate of large pump, can be changed to two smaller pump work, two standby (a total of four)
3, for some large pumps, the pump parallel operation of 70% flow requirements can be selected, without the backup pump, in a pump maintenance, another pump is still responsible for the production of 70% of the transmission.
4, the need for 24 hours of continuous non-stop operation of the pump, should spare three pumps, a operation, a standby, a maintenance.
Parameter selection
Water supply pressurizing station is an effective measure to relieve the shortage of water supply pressure in cities, the core of which is to lift the pump station, and the core of the pump station is the pump. The choice of pump not only affects whether the water supply pressure station can work normally, but also directly affects the operation cost of the pump station.
The centrifugal pump is usually used in the general water supply pressurizing station in China. The centrifugal pump has the advantages of simple structure, no pulsation of infusion and simple flow regulation. According to the actual situation of the project, the category of the centrifugal pump is selected first and considered as follows.
(1) According to the characteristics of the medium to determine which characteristics of the pump. Such as clean water pump, corrosion pump, or chemical process pump and impurity pump. When the medium is highly toxic, valuable or radioactive and other substances that are not allowed to leak, the non-leakage pump (such as shield pump, magnetic pump, etc.) or the double-end mechanical seal with leakage collection and leakage alarm device should be considered. If the medium is liquefied hydrocarbons and other volatile liquid should be selected low cavitation margin jump, such as barrel pump.
(2) According to the site installation conditions, choose horizontal pump, vertical pump (containing liquid pump pipe pump).
(3) According to the size of the flow of single suction pump, double suction pump, or small flow centrifugal pump.
(4) According to the height of the head to choose a single stage pump, multistage pump, or high-speed centrifugal pump.
After the above determination, we can choose the appropriate pump series according to the characteristics of different series of pumps and the conditions of the production plant. Pump type, series and materials selected, and then according to the pump manufacturer provided samples and related parameters to determine the type of pump.