Application of KE300A Frequency Converter in Constant Pressure Water Supply Industry

2023-03-15

Overview

Constant pressure water supply refers to the water supply method in which the outlet pressure remains constant when the water consumption in the water supply network changes.The outlet pressure value of the water supply network system is determined according to user needs.The traditional constant pressure water supply method is realized by using water towers, high-level water tanks, air pressure tanks and other facilities. With the increasing maturity and wide application of frequency conversion speed regulation technology, the organic combination of frequency converter, PID regulator, single-chip microcomputer, PLC and other devices constitutes a control system to adjust the output flow of the water pump and realize constant pressure water supply.The technology is widely used in the water supply industry.Main features of variable frequency constant pressure water supply system:

1.Energy saving, which can save 20%-40% of electricity and realize green electricity consumption.

2.Small footprint, low investment and high efficiency.

3.Flexible configuration, high degree of automation, complete functions, flexible and reliable.

4.Reasonable operation, due to soft start and soft stop, not only can eliminate the water hammer effect, but also reduce the average torque and wear on the motor shaft, reduce the amount of maintenance and maintenance costs, and greatly increase the life of the pump.

5.Because the frequency conversion and constant pressure speed regulation directly supply water from the water source, the secondary pollution of the original water supply mode is reduced, and the source of many infectious diseases is prevented.

6.Through communication control, unattended operation can be realized, which saves manpower and material resources.

The Main Application Occasions of Frequency Conversion Speed Regulation Constant Pressure Water Supply Equipment

1.High-rise buildings, urban and rural residential areas, enterprises and institutions, etc.

2.Various industries need constant pressure control of water, cooling water circulation, heating network water circulation, boiler water replenishment, etc.

3.Central air-conditioning system.

4.Pressurization system of waterworks.

5.Farmland irrigation, sewage treatment, artificial fountains.

6.Various fluid constant pressure control systems.

Introduction of Energy Consumption of Injection Molding Machine

Frequency converter is the core part of the whole frequency conversion constant pressure water supply system.The block diagram of its system is shown in the figure below:

Frequency conversion constant pressure water supply system block diagram

变频器 Frequency converter

水泵电机 Water pump motor

频率指令 Frequency command

运行指令 Running instructions

给定 Given

反馈 Feedback

PID控制器 PID controller

压力传感器 Pressure sensor

出水口压力检测点 Outlet pressure detection point

用户 User

In the figure, the water pump motor is the output link, and the speed is controlled by the frequency converter to realize variable flow and constant pressure control.The frequency converter receives the signal from the PID controller to control the speed of the water pump.The pressure sensor detects the water pressure of the pipe network and transmits the signal to the PID controller.The PID controller adjusts the frequency of the frequency converter to control the speed of the water pump, realizing a closed-loop control.system.The frequency converter itself has the function of PID regulation, and the external PID regulator may not be selected.

System Control Diagram (Take One Inverter to Control 4 Motors As an Example)

供电电源 Power supply

变频泵 Variable frequency pump

变频器 Frequency converter

工频泵 Power frequency pump

When the operating frequency of the inverter reaches the upper limit frequency and after a certain delay, the T1 relay closes the output, the KM1 contactor closes, and the 1# power frequency pump starts and runs directly at the power frequency.If the pressure is not enough, when the operating frequency of the inverter continues to reach the upper limit frequency, the 2# and 3# power frequency pumps will be started in a cycle.

When the operating frequency of the frequency converter reaches the lower limit frequency, and after a certain delay, the corresponding power frequency pump will be started at the end and stop working, according to the principle of starting first and then stopping.

交须器输出频率 Output frequency of whisker

等于下限频率 Equal to lower frequency

辅泵停止延时计时 Auxiliary pump stop delay timing

延时时间到 Delay time to

依次停止使能的辅泵 Stop the enabled auxiliary pump in turn

等于上限频率 Equal to upper limit frequency

结束 End

辅泵启动延时计时 Auxiliary pump start delay timing

依次启动使能的辅泵 Start the enabled auxiliary pump in turn