The exhaust temperature of a screw air compressor is restricted by the upper and lower temperatures. The technical engineer of Mengma Filter will take you to understand the key component for temperature control of a screw air compressor - the temperature control valve.
1,The upper and lower temperature limits of the exhaust temperature
The exhaust temperature of the screw air compressor is sampled near the outlet of the compression main unit, that is, the temperature of the oil-gas mixture at the outlet of the main unit. The most important thing in controlling the outlet temperature of the compression host is to control the oil injection temperature of the compression host, and the temperature control valve is responsible for this important task.
The exhaust temperature of screw air compressors has special requirements. It should neither be too high nor too low. That is, there are two temperature limits, upper and lower.
The exhaust temperature of the screw air compressor is too high. High temperatures can cause tripping, carbon deposits, reduced efficiency and even damage to components. The general upper limit of exhaust temperature control is 110 ℃.
However, the lower limit value of temperature is affected by environmental temperature, humidity and pressure, and it is a variable value. The purpose is to prevent the formation of condensation water during operation, which can cause the emulsification of lubricating oil, damage the cooling and lubrication effect of the unit, and deteriorate the performance of the unit.
2,Lubrication and cooling system for screw air compressors
Screw air compressors belong to positive displacement compressors. Their cooling and temperature control are achieved by spraying a large amount of lubricating oil into the cylinder to remove heat, which is an internal cooling method and has a more significant cooling effect. Compared with adiabatic processes and indirect cooling methods, the cycle indication power required is less, reducing power consumption and improving efficiency.
3,Principle and Structure of Air Compressor Temperature Control Valve
To ensure the precise control of the exhaust temperature of screw air compressors, the temperature control valve is a key component in the lubricating oil cooling system for temperature control. This valve is a type of valve that uses special temperature-sensing paraffin as the valve core to control the temperature of the fluid. It utilizes the linear volume expansion characteristic of paraffin during the solid-liquid phase change process to convert the temperature change signal into the displacement change of the valve core to control the lubricating oil flowing through the oil cooler.
When the oil temperature from the oil and gas tank is high and rises to the control point, the thermal dynamic element pushes the valve core to overcome the force of the spring and move downward. The higher the temperature, the greater the displacement of the valve core, and the larger the valve opening leading to the oil cooler. When the oil temperature reaches the upper limit of the temperature range of the thermal dynamic element, the opening is fully opened, and at this time, all the oil passes through the oil cooler.
When the oil temperature drops, the thermal power element has the opposite effect as mentioned above. When the oil temperature falls below the temperature sensing range of the thermal power element, the valve core returns to its initial position, and all the valve openings leading to the oil cooler are closed. The oil coming out of the oil and gas tank flows directly to the screw compressor without passing through the oil cooler.