There are three main control methods for automatic booster pumps: differential pressure, water level and variable frequency control.
1. Differential pressure type: The differential pressure type is based on the upper and lower limit pressure values. When used, the upper limit stop pressure value and the lower limit start pressure value are defined. After the normal operation, when the pipe network pressure reaches the upper limit pressure, the controller feeds back to the control system. Under the cooperation of various electrical components, the booster pump is de-energized to maintain pressure; when the water pressure causes the pipe network pressure to continuously drop to the lower limit pressure, the controller feeds back to the system, and the booster pump is powered on again. This cycle, to achieve the purpose of automatic boost. Now some advanced differential pressure automatic booster pumps have been added to the water flow combined control system, that is, there is no upper limit of shutdown, the water consumption is small but there is water flow, and there is no downtime.
2, water level: water level controller is what we often say float switch, is based on high and low water points work. The float switch is in the downward state at the low water level, and the start signal is output at this time; when the high water level is facing upward, the stop signal is output at this time. When the water-filled pool is full of water, the float ball is floated up and is in the upward state. At this time, the controller is given a shutdown power-off signal, and the booster pump stops running. Conversely, there is less water or water shortage. The state of the float has changed, and the feedback start signal is sent to the booster pump to restart the pumping. So cycle back and forth. . . . . .
3. Frequency conversion type: The frequency conversion is based on the closed-loop control system. The so-called closed-loop control is the control method for correcting according to the output feedback of the control object. It is corrected according to the quota or standard when measuring the actual deviation from the plan. Closed-loop control, the control signal is taken out from the output change as the comparison quantity is fed back to the input control input quantity. Generally, this take-off quantity and the input quantity are opposite in phase, so it is called negative feedback control, and industrial automatic control is usually based on the closed-loop control concept. Simply put, the closed-loop control principle of the variable frequency water pump is to compare the [actually set target pressure value] with the [currently detected pressure value], and change the difference to approaching and zero by some column function algorithm. can. In the frequency conversion speed regulation process of the pump equipment, when the water pressure drop speed is fast, the speed regulation process of the frequency converter is accelerated, and vice versa. In the case of a flow head up to standard, the output pressure of the variable frequency control mode can always be constant.
Booster pump control form:
1 water flow switch 2 flow switch 3 pressure sensing 4 valve reed switch
Control the operation of the pump to enable automatic increase of the pressure inside the pipeline. The control method is of course controlled by pressure, because the pressure is required.
There are a variety of sensors for detecting pressure changes. Electric contact pressure gauges, pressure relays, capacitive or strain gauge sensors, etc., coupled with corresponding control circuits, can control the operation of the pump to achieve a certain pressure.
From the working state of the pump, there should be two ways of intermittent work and continuous work:
1. The pump is intermittently pressurized to keep the pressure within a certain range: when the pressure is lower than a certain value, the pump starts to pressurize the pump. When the minimum pressure exceeds a certain value, the pump stops, and when the pressure is lower than the predetermined value, the pressure is started again. The pressure inside the pipeline varies widely, and the booster system consisting of an electric contact pressure gauge, a pressure relay and a water pump is basically this type.
2. The continuously operating booster pump can keep the pipeline pressure at a certain value. The sensor detects a small change in pressure, and the control system converts it into control of the pump power supply (such as frequency change), thereby changing the output power of the motor. Changing the output pressure of the pump to achieve a constant pressure for the system, the pressure inside the system is relatively stable, of course, the boosting cost is also higher.
3. There is also a domestic booster pump, which is controlled by water flow. The control is realized by a valve flap with a permanent magnet installed in the water outlet pipe of the pump. Once the water flows in the pipe, the valve is pushed. When the flap rotates, the position of the magnet changes, so that the reed switch fixed outside the pipeline is closed, the pump power is turned on to make the pump work, and the outlet pressure is increased; once the water stops, the water flow in the pipeline is stopped, the valve flap is reset under the action of the spring, and the magnet is left. The reed switch, the reed switch is disconnected, and the pump stops working. This mode of operation works as long as the water flow pushes the valve and the pump operates regardless of the pump output pressure.