Compressor Switch

working principle
It is mainly used to adjust the start and stop status of the air compressor. By adjusting the pressure inside the air storage tank, the air compressor can stop and rest, which has a maintenance effect on the machine. During the debugging of the air compressor factory, adjust it to the specified pressure according to the customer's needs, and then set a pressure difference. For example, when the compressor starts to start, inject air into the air storage tank, and when the pressure reaches 10kg, the air compressor stops or unloads, When the pressure reaches 7kg, the air compressor starts to start again, and there is a pressure difference during this process, which can allow the compressor to rest and protect the air compressor.
The compressor is directly driven by an electric motor, causing the crankshaft to rotate and the connecting rod to cause the piston to reciprocate, causing a change in cylinder volume. Due to changes in pressure inside the cylinder, air is forced through the intake valve to pass through the air filter (muffler) and enter the cylinder. During the compression stroke, due to the reduction of cylinder volume, compressed air passes through the exhaust valve and enters the air storage tank through the exhaust pipe and one-way valve (check valve). When the exhaust pressure reaches the rated pressure of 0.7MPa, it is automatically stopped by the pressure switch control. When the pressure of the air storage tank drops to 0.5-0.6MPa, the pressure switch automatically connects and starts.
Switch structure
For different temperature measurement ranges, temperature switches with different structures should be selected. In the temperature range of 0 ℃~100 ℃, solid expansion type temperature switches are usually used. In the temperature range of 100 ℃~250 ℃, gas expansion type temperature switches are mostly used. For the temperature range above 250 ℃, only thermocouples or thermal resistance thermometer can be used, which are converted into analog electrical signals through measurement transmitters, Then convert the electrical signal into a switching signal [6].
The working principle of a solid expansion temperature switch is to use the difference in length of different solids after being heated to generate displacement, which causes the contact to act and outputs a temperature switch signal. For example, there is a temperature switch composed of bimetallic sheets (brass sheets stacked on indium steel sheets). Due to the larger linear expansion coefficient of brass sheets compared to indium steel sheets, the bimetallic sheets will bend when heated. When the specified temperature is reached, the free end of the bimetallic sheet (the moving contact of the temperature switch) generates sufficient displacement, disconnects from the fixed static contact, and sends a switching signal.
The gas expansion temperature switch operates according to the principle of a gas pressure thermometer. It has a temperature measurement package filled with nitrogen gas and connected to the measuring element of the pressure switch through a sealed capillary. When the measured temperature reaches the specified value, the inflation pressure inside the temperature bulb causes the pressure switch to operate.