It is the absolute dry goods! The Use and Adjustment of Pressure Controller in Refrigeration and Air Conditioning System

Many pressure controllers are used in refrigeration systems, and the pressure is controlled by the on-off of contacts. There are mainly high pressures controllers, low pressure controllers, high and low pressure controllers, differential pressure controllers and oil pressure protection pressure controllers. The action principle of the pressure controller is basically the same, which is detected by the pressure detection mechanism and controlled by the actuator. The bellows are compressed to produce expansion deformation, which drives the swing rod to move. Then the swing rod moves the contacts to open and break so as to control the pressure. Two parameters, DIFF and RANGE, are often seen in pressure controllers. RANGE is the range of pressure, and DIFF is the pressure difference, which refers to the switching difference. In the other word, it is the dead zone, which is a switching area. Each pressure switch has this parameter, and the switching difference of the controller can be adjusted or not according to different requirements. Adjustable setting point is called adjustable setting point; otherwise it is not adjustable setting point.

For example, the fixed working pressure difference of Jy616 pressure controller is 0.5-1 kgf/cm2, which fixes the pressure difference in a certain range. High-Pressure Pressure Controllers and Low-Pressure Pressure Controllers:

(1) Action principle: High-pressure pressure controllers and low-pressure pressure controller have the same function principle. When the pressure in the bellows rises and its value is higher than the setting value of the main adjusting spring, the bellows extend or shorten (the external compression type of bellows is shortened, the internal compression type is elongated), push the swing rod, move the contacts, cut off the power supply to play a high-voltage protection role. If the power supply is cut off when the pressure is too low, it will play a low-voltage protection role. Taking the high-pressure pressure controller as an example, the range of control pressure is introduced. When the pressure is P1, the contacts are open, and when the pressure is P, the contacts are broken. The working pressure difference ranges from P to P1. When the pressure is high, the contact breaks, and when the pressure drops to point P1, the contact opens. When the pressure rises to point P, the contact breaks off again. The action of the low-pressure pressure controller is the opposite.

(2) Work pressure difference: Work pressure difference refers to the working pressure interval between on and off contacts. If the disconnection pressure of the high-voltage controller is set at 14kg and the working pressure difference is set at 2kg, the controller will be disconnected when the pressure exceeds 14kg, and the controller will be connected when the pressure is lower than 12kg. Reducing the working pressure difference can improve the control accuracy. But don't adjust it too small, otherwise it will move frequently. Controller contact action should be flexible, to instantly on and off, otherwise spark discharge will occur, burning contact.

(3) Structure and adjustment: When the pressure of the input bellows increases, the bellows bottom plate moves (the movement is determined by the difference between the pressure and the spring force), driving the swing rod and controlling the contact action. When it is necessary to adjust the pressure control range, rotate the pressure adjustment screw counterclockwise/clockwise, and adjust the pressure set by oneself with the multimeter.
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