Advantages of constant pressure water supply system using variable frequency speed regulation

In domestic water and industrial water, as well as various boilers, fire-fighting and other water supply systems, traditional high-level water tanks, pneumatic pressurization and other equipment are used. These equipments are not only expensive to invest, but also difficult to maintain, and they cannot meet the demand for large-flow water supply. The constant pressure water supply system adopting frequency conversion speed regulation overcomes the shortcomings of the traditional water supply method and is a relatively perfect water supply system. The advantages of variable frequency speed regulation constant pressure water supply system are: water supply is safe, energy saving and convenient. Its characteristics are: adjust the operating parameters of the system according to the change of water consumption, keep the water pressure constant.

The control mode of the water supply system is that the power consumption of the pump is proportional to the third power of the speed, and the water pump is designed according to the power frequency running speed. When the water supply is in addition to the peak, most of the time flow is small, and the frequency converter can be used to make the pump run. The speed changes with the flow rate to achieve energy saving. Energy efficiency can reach about 30%. The inverter for water supply is used, which integrates the programmable controller and the inverter. The water pressure signal fed back by the sensor is directly sent to the inlet of the loop regulator that is provided by the inverter, and the pressure setting can use the inverter. The keyboard setting can also be fed in the form of an analog potentiometer. Daily multi-stage pressure operation can be set to meet the needs of water supply pressure, and the specified daily water supply pressure can also be set. The plate surface can directly display the pressure feedback value.

Control system of water supply system The control system of the variable frequency constant pressure water supply system passes the remotely measured pipe network pressure. After processing, the control signal is sent to the inverter to adjust the output frequency of the inverter to achieve constant pressure water supply of the pipe network. In order to prevent the water hammer phenomenon, the start and stop of the pump will link its outlet valve. (1) Automatic opening of the pump The automatic opening of the pump can only be achieved in the fully automatic control mode of the controller. Under normal circumstances, the control collects the pressure of the pipe network, and after the controller calculates the control signal, it transmits the control signal to the inverter, automatically adjusts the output frequency, and performs constant pressure variable water supply. However, when the frequency of the inverter has risen to 50Hz or dropped to 20Hz, and the pipe network pressure still fails to meet the requirements, the controller will execute the pump opening procedure. The pressure signal is also used as the source of the squib alarm. When the pressure of the pipe network suddenly drops and the flow rate of the effluent exceeds the normal value, the host computer will give an audible and visual alarm and record the alarm information.

(2) The program starts to detect the water level. If the water level reaches the pumping water level, start the pumping process, start the water pump, and start the vacuum pump to vacuum when the pump is turned on. If the vacuum is formed, the valve can be opened and the pump is completed. If the vacuum fails, the vacuum pump is turned off, the pump is stopped, and an alarm is issued.

(3) Open pump program When the inverter rises to 50Hz and the pipe network pressure is still lower than the set value, the controller starts timing. If the pipe network pressure reaches the set pressure value within the specified time, the controller stops counting and continues to regulate the voltage. During the specified time, if the pipe network pressure is still lower than the set pressure value, the controller first reduces the frequency of the inverter to a certain range, and then starts the constant pressure pump.

(4) Stop the pump program When the inverter drops to 20 Hz and the pipe network pressure is still higher than the design pressure value, the controller starts timing. During the specified time, if the pipe network pressure drops to the set pressure value, the controller stops counting and continues to adjust the frequency conversion. If the pipe network pressure is still higher than the design pressure value within the specified time, the controller stops the constant pressure. The frequency of the pump and the inverter is increased to meet the pressure requirement of the pipe network; if the pipe network pressure is still higher than the design value, the controller stops the constant pressure pump until the pipe network pressure reaches the design value. When stopping the pump, first close the outlet valve to the 1/3 position, then stop the pump and finally close the valve.

The conclusion uses the variable frequency constant pressure water supply system to replace the traditional water supply methods such as high water tank, pool, water tower and pressure tank water supply, eliminating the secondary pollution of water quality, and is more conducive to energy saving, convenient operation and high degree of automation; The peaking capacity of the water supply is obviously improved, which not only regulates the peak water, but also reduces the pumping time and frequency, and prolongs the service life of the pump.