Operation mode of constant pressure water pump system
Usually, multiple common pumps are set in the same water supply system. When the water supply is large, multiple pumps are fully opened,
One or two sets shall be opened for each hour of water supply. When frequency conversion speed regulation is used for constant pressure water supply, there are two ways: one is that all pumps are equipped with a frequency converter; Second, each pump is equipped with a frequency converter. According to the pressure feedback signal, the latter method automatically adjusts the output frequency of the frequency converter through PID operation, changes the motor speed, and finally achieves the goal of constant pressure of the pipe network. It is a closed loop loop, which is simple but costly. The former method has low cost and no worse performance than the latter, but the control program is more complex, which is the future development direction.
The general water supply system, due to the requirements of water supply volume and reliability, adopts the mode of parallel operation of multiple pumps. This is also conducive to achieving economic operation by adjusting the number of pumps when the water supply varies in a large range. However, only adjusting the number of pumps can not ensure constant pressure water supply, and its operation efficiency is not high. The water pump adopts the speed to regulate the flow, and the economy of operation is the best. However, for water supply systems with large capacity, if full capacity speed regulation is adopted, the investment is too large and unnecessary. Therefore, for the water supply system with multiple pumps, a speed regulating pump can realize constant pressure water supply within the full capacity range, while other pumps only need to operate at a constant speed. Namely, the number adjustment and speed adjustment are used to jointly ensure the constant pressure water supply within the variation range of water supply.
The speed governing pump in the system is generally driven by a frequency converter. In addition to achieving constant pressure water supply by adjusting the speed of the water pump, the frequency converter can also be used as a soft starting device for other pumps by switching control.
