What are the characteristics of self-priming centrifugal pumps?

Point one:

According to the design flow rate, the required lift, select the pump, and consider the self-priming centrifugal pump due to wear and other reasons, the self-priming centrifugal pump output is reduced, the pump can be selected according to the calculated head H multiplied by 1.05 ~ 1.10 coefficient; the characteristic curve should be selected In order to increase the head of the self-priming centrifugal pump with the flow rate increasing, such a pump is stable and reliable in parallel operation; and the operating point of the self-priming centrifugal pump should be kept in an efficient range, which is energy-saving and not easily damaged. Machine parts.

Point two:

The variable frequency speed control pump (group) is designed to meet the requirements of the maximum design second flow rate in the domestic water supply system. The power supply must be reliable (dual power supply or dual loop power supply); the working point of the self-priming centrifugal pump should be selected in the high efficiency working area of the self-priming centrifugal pump characteristic curve (QH curve), and should not be selected on the extension line of the QH curve. The most unfavorable working point of the design should be at the right end of the high-efficiency section of the characteristic curve of the self-priming centrifugal pump, that is, the intersection of the low point of the high-efficiency zone of the characteristic curve of the self-priming centrifugal pump and the characteristic curve of the pipeline. The self-priming centrifugal pump speed adjustment range should be set between 25% and 100% of the self-priming centrifugal pump water supply.

Point three:

The lifting pump for selecting the water tank and water tower should minimize the number of pumps, and should use one for each; when the single pump can meet the requirements, it is not suitable to use multiple parallel modes; if multiple parallel operation or large and small pumps must be used, The model number and number of units should not be too much, and the models should generally not exceed two types. The lift range of self-priming centrifugal pumps should be similar.

Point four:

The self-priming centrifugal pump unit of the domestic pressurized water supply system shall be provided with a standby pump. The water supply capacity of the standby pump shall be greater than the water supply capacity of the largest self-priming centrifugal pump. The self-priming centrifugal pump shall be automatically switched and alternately operated.