Selection of horizontal centrifugal pump:
Reasonable selection of horizontal centrifugal pump, the need to take into account the pump unit, pump station investment and operating costs and other comprehensive technical and economic indicators, so that it is in line with the principles of economic, safe and applicable. Specifically include the following aspects:
1, should choose high efficiency, low noise, energy saving pumps, is strictly prohibited to choose out of the product.
2), according to the design flow, required lift pump selection, and consider the horizontal centrifugal pump because of wear caused by decreased pump output, according to the calculated lift H multiplied by 1.05 ~ 1.10 coefficient of pump selection should be chosen; characteristic curve for the head decreased gradually with the increase of runoff water pump, the pump is stable like this. Working in parallel and reliable; the operating point and the pump should keep running in the high range, thus saving energy and not easily damaged parts.
3. When the water supply pipe network is not regulated, it is advisable to use variable speed pump group or rated speed pump group. The maximum output of the pump should not be less than the design flow of the district water supply, and should be checked by the fire condition.
4), select the lift pump tank, water tower should minimize the number of pumps should be a one; when the single pump can meet the requirements, can not use multiple parallel mode; if must use the pump operation or the size of multiple parallel collocation method, its type and number should not be too much, more than two models are generally not, the pump head range should be similar; parallel operation of each pump should still run in high efficiency range.
5), frequency conversion speed pump (Group) design water supply should be guaranteed to meet the design requirements of the life of the water supply system of the second largest flow. The power supply shall be reliable (double power or double loop power supply); pump operating point should be selected in the pump characteristic curve (Q-H curve), the work area, and shall not be selected in the Q-H curve of the extension line, design the most unfavorable work point should be right at the end of the characteristic curve of water pump, pump out the water section, i.e., maximum while the head is low but it can meet the requirements, it is low and the pipeline characteristic curve of pump characteristic curve, the intersection area. Water pump speed regulation can be as high as possible in the pump section; speed range should be located in the pump water supply of 25% ~ 100%; equipment should have the water level automatic control function.
6, the life of the pressurized water supply system of water pump units should be set aside, standby pump water supply capacity should be greater than the maximum operating capacity of a water pump, the pump should be automatically switched, alternating operation.
7) horizontal centrifugal pump with the motor voltage should be the same, and the power system should be the same as the national grid power supply system.