Pressure relays are mainly used to detect the level of liquid or gas pressure and send out switching signals to control solenoid valves, hydraulic pumps and other equipment to control the level of pressure.
The pressure relay is mainly composed of a pressure transmission device and a micro switch. The liquid or gas pressure pushes the rubber membrane and the sliding rod through the pressure inlet and moves upward against the reaction force of the spring. When the pressure When the set pressure is reached, the micro switch is touched to send a control signal, and the set pressure can be changed by rotating the pressure regulating nut.
Pressure relay is a hydraulic-electric conversion component that uses the pressure of liquid to open and close electrical contacts. When the system pressure reaches the set value of the pressure relay, an electrical signal is sent to cause the electrical components (such as electromagnets, motors, time relays, electromagnetic clutches, etc.) to operate, causing the oil circuit to depressurize and reverse direction, and the actuators to realize sequential actions. Or turn off the motor to stop the system from working, for safety protection, etc.
When the liquid pressure entering from the oil inlet 3 at the lower end of the relay reaches the set pressure value, the plunger 2 is pushed upward. This displacement is amplified by the lever and then pushes the micro switch 4 action. Changing the compression amount of spring 1 can adjust the operating pressure of the relay.
Application occasions: used for safety protection, controlling the sequential action of actuators, opening and closing of pumps, and unloading of pumps.
Note: The pressure relay must be placed where there is a significant change in pressure to output an electrical signal. If the pressure relay is placed on the oil return line, since the oil return line is directly connected to the fuel tank, the pressure will not change, so the pressure relay will not work.
Graphic symbol of pressure relay
In the circuit diagram, the text symbol of the pressure relay is represented by KP, and its graphical symbol is as shown in the figure below.
Instructions for using pressure relay
1. Select a relay that meets the requirements based on the specific use or system pressure. At the same time, in order to ensure the sensitivity of the device's action, it is necessary to avoid operating in the system. The use of high voltage pressure relays occurs.
2. Also, the relay should be installed in the correct way according to the regulations in the instruction manual.
3. Wire the microswitches in the equipment according to the power supply form and specific requirements of the actual application.
4. After the adjustment is completed, its position needs to be locked and fixed to prevent changes caused by vibration during future work.
5. FinallyThe oil discharge cavity of the pressure relay should be directly connected to the oil return tank, otherwise it will easily cause the back pressure at the oil discharge port to be too high and affect its sensitivity.
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