Application of Sifang Constant Pressure Water Supply Unit in Water Supply System

Abstract: This project describes the application of Sifang constant pressure water supply control unit in the multi-pump constant pressure water supply control system. The Sifang water supply control unit is used in conjunction with the Quartet E380 series frequency converter to realize a multi-pump constant pressure water supply system with flexible configuration and wiring. Convenience and other advantages.

Keywords: E380; frequency converter; multi-pump constant pressure water supply; water supply control unit I. INTRODUCTION Large-scale water supply and drainage systems have a wide range of applications in industrial and agricultural production, daily life, etc. These large-scale water supply and drainage systems are often not composed of a single water pump. Instead, it is composed of multiple pumps. How to realize the energy saving and consumption reduction of the large-scale water supply and drainage systems controlled by these multi-pumps. This plan describes a multi-pump constant pressure water supply control based on the Quartet SIA-100 multi-pump constant pressure water supply control unit. system.

Second, multi-pump constant pressure water supply control system structure Multi-pump constant pressure water supply control system structure shown in Figure 1, from a plurality of pumps (motor pump group), pressure sensors, constant pressure water supply control unit, inverter and other components. The pressure sensor will detect the change of pressure in the pipeline at any time, and send the detected analog signal to the constant pressure water supply control unit. After the water supply control unit compares with the set pressure, the inverter will control the speed of a certain pump automatically. And the input and exit of multiple pumps will keep the pipe network at a constant set pressure to meet the user's requirements, so that the entire system will always remain in the best state of high efficiency and energy saving. If the water consumption is very small, after the constant pressure water supply control unit analyzes and confirms, the main water supply system will automatically stop running and the dormant pump will be started to maintain the pipe network pressure and a small amount of water. When the water consumption reaches the level at which the dormant pump cannot maintain the set pressure, the main The water supply system starts automatically and the dormant pump stops running, which improves the safety of the system operation and achieves significant power saving effects.

Chart 1 multi-pump constant pressure water supply control system structure diagram

Third, the Quartet constant pressure water supply control system program introduction Quartet multi-pump constant pressure water supply control unit with E380 frequency converter and realize the system of constant pressure water supply control. According to the difference between the current pipe network pressure and the set pressure, the system adjusts the current operating frequency of the variable frequency pump. If the set pressure is still not reached, the quantity of the water supply pump is automatically increased or decreased, and the frequency conversion is performed. The pumps of the system can be used at regular intervals so that the utilization of each pump can be equalized and system reliability can be increased.

The four-party multi-pump constant pressure water supply control unit is simple in application and powerful in function and can control up to 6 to 8 pumps. According to the configuration of the water supply system, multi-pumped cycle frequency conversion and one main multi-supply constant pressure water supply can be realized, with regular rotation. Control, timing water supply control, water shortage shutdown control, daily setting of 6-stage pressure control (settable on weekdays and weekends respectively), hibernation function, re-powered self-start after power off, and RS485 interface for remote monitoring.

1. Water supply method 1: Multi-pumped circulating frequency conversion constant pressure water supply Multi-pumped circulating frequency conversion working control method is applicable to water supply occasions with the same pump capacity (except dormant pumps), and one inverter controls each pump in turn to achieve soft start during operation. And speed adjustment, to achieve constant pressure water supply. Figure 2 Water supply system definition M1, M2 is a variable frequency pump, M3 is a dormant pump, power on, first connect the KM1 contactor, start the M1 pump frequency conversion work, when the M1 pump operating frequency reaches 50HZ, extended for a certain time (The state switching judgment time is set within 0.1~5.0Sec.) If the feedback pressure still fails to reach the given pressure value, disconnect KM1 and turn on KM2 to convert the M1 pump from inverter state to industrial frequency operation state. After a certain period of time (setting of the electromagnetic contactor interlock delay time within 0.1~5.0Sec), connect KM3 to start the M2 pump for frequency conversion. When the system is overpressured, when the M2 pump is running at the lower limit frequency, the system will still be overpressured after a certain time delay. The KM2 will be disconnected and the M1 pump power frequency will be cut off (when the power frequency pump is used for a long time, the system will first cut off the pump with long running time. ), The frequency conversion adjustment by the M2 pump keeps the system pressure stable. The same as before, the constant pressure water supply control unit can control the cycle frequency of 8 pumps. When the system has only one frequency conversion main pump working, and the operation reaches the lower limit frequency, the feedback pressure reaches the dormant pressure value, and it is considered that the system is not short of water or the water consumption is small, the frequency conversion pump is turned off, and the dormant pump is turned on. When the feedback pressure is less than the dormant pressure value, the dormant pump is turned off and the variable frequency pump is restarted.

2. Water supply method 2: A main multi-supply constant pressure water supply method 2 is applicable to a water supply occasion where the pump capacity is large and the remaining pump capacity is small. The larger capacity one is used as the main pump, which is driven by the inverter. The smaller pump is used as an auxiliary pump and starts directly at the power frequency. All the pumps do not need to switch between frequency conversion and power frequency. When the pump is added, the power frequency starts one auxiliary pump with the longest stopping time. When the pump is reduced, it stops one. The longest running auxiliary pump. The constant pressure water supply control unit can be equipped with one inverter pump, seven auxiliary pumps or dormant pumps. Figure 3 defines the definition of the water supply system M1 inverter pump, M2, M3 auxiliary pump, M4 sleep pump. When the working frequency of M1 reaches 50HZ, after a certain time delay (set within the electromagnetic contactor interlock delay time 0.1~5.0Sec), if the feedback pressure still fails to reach the given pressure value, then connect KM2 directly to start M2 The auxiliary pump is put into operation. When the working frequency of M1 reaches 50 Hz again, after a certain time delay, if the feedback pressure still fails to reach the given pressure value, turn on the KM3 to start the M3 auxiliary pump and put it into operation. If the system is over pressure, turn off the M2 auxiliary pump first, and then turn off the M3 auxiliary pump. When the system only has the M1 variable frequency pump working and runs at the lower limit of the frequency, the feedback pressure reaches the dormant pressure value, and it is considered that the system is not short of water or the water consumption is small. Turn off the M1 variable frequency pump and switch on the M4 dormant pump. When the feedback pressure is less than the dormant pressure value, the dormant pump is turned off, the variable frequency pump is restarted, and the cycle operation is performed.
Figure 3 water supply method two electrical diagram Fourth, the program features 1, the water supply mode can choose multi-pumped cycle frequency conversion mode or a main multi-assisted mode;

2, regular rotation control, to ensure that each pump can get equal opportunity and time to run, to prevent the rust of the pump;

3, timing water supply control and operating pressure at different times can be flexibly set, suitable for factory water and other occasions;

4, the dormancy function can guarantee the greatest degree of energy conservation;

5, with water, overload and other protection functions and power-on self-start function. V. Summary The multi-pump constant pressure water supply control system based on the Quartet constant pressure water supply control unit is simple, powerful, energy-saving effect is significant, simply by simple parameters The set-up and peripheral circuit design can meet the high-efficiency energy-saving requirements of different water supply control systems, and have high promotion value in industrial and agricultural production and life.

references:

1. "SIA-100 multi-pump constant pressure water supply control unit specification" Shenzhen Sifang Electric Technology Co., Ltd. 2. "E380 Series Universal Inverter Product Manual" Shenzhen Sifang Electric Technology Co., Ltd.

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