What are the protection devices of industrial chillers

What are the protection devices of industrial chillers

Industrial chiller is a kind of water cooling equipment that can provide constant temperature, constant current and constant pressure cooling equipment. The principle of the chiller is to inject a certain amount of water into the internal water tank of the machine, and the water is cooled by the chiller refrigeration system, and then a water pump inside the machine injects low-temperature frozen water into the equipment that needs to be cooled, and the chilled water will The heat is taken away, and the high-temperature hot water is returned to the water tank to cool down again, so that it is circulated and exchanged and cooled to achieve the effect of cooling the equipment.

During the working process of industrial chillers, in order to ensure normal operation, the chillers will have protection devices. The general protection devices include suction and exhaust pressure protection, oil pressure difference protection, cooling water jacket cut-off protection and other measures. These protection measures are specific How does it work? Please see the specific analysis below.

　　 1. Suction and discharge pressure protection: mainly to prevent the compressor suction pressure from being too low and the discharge pressure from being too high. With the pressure controller, when the suction pressure and the discharge pressure reach the warning pressure value, the compressor will stop running.

　　2. Oil pressure difference protection: It is used for compressors with oil pumps to prevent the oil pump from being oiled to affect compressor lubrication and cause the cylinder unloading mechanism to fail to work normally. The protection method is to use the oil pressure difference controller to detect the oil pressure difference between the inlet and outlet of the oil pump. If the oil pressure difference continues for about 60g and does not reach the normal value (about 0.15MPa), the compressor will be stopped.

　　3. Compressor discharge temperature and oil temperature protection: To prevent the discharge temperature from being too high and the oil being too low or too high. Use a temperature controller to stop the compressor when the above temperature reaches the warning value.

　　4. Cooling water jacket cut-off protection: The cylinder head of the ammonia compressor is equipped with a cooling water jacket to apply external cooling to the compression process. The cooling water cut-off protection control of the water flow relay seat, if the continuous cut-off reaches the specified time, the compressor will be controlled to stop. In a refrigeration system that uses a refrigerant liquid pump to force a liquid supply cycle to the evaporator, if the pump does not run overnight, it will cause cavitation damage to the refrigerant liquid pump and burn the motor. Use the pressure difference controller to detect the fluid pressure difference before and after the pump. If the pressure difference does not reach the normal value for 8-15s, the pump will be controlled to stop running.

　　 The cooling water system and cold water system outside the refrigeration system also use cooling water pumps and cold water pumps. These water pumps will encounter the same problems during operation, and the same protective control is implemented by the pressure difference controller. The high-pressure container in the refrigeration system of the chiller (such as the water-cooled condenser with the refrigerant on the shell side, high-pressure liquid reservoir, etc.), in order to avoid the shell damage when the internal pressure is too high, a safety valve is provided on the container. The safety valve automatically opens when the internal pressure exceeds 10% of the control value, and the high-pressure medium in it is released urgently to suppress the increase in the internal pressure of the container.

　　 Small size high pressure vessel can use simpler fusible plug or safety film. When the temperature (pressure) in the container exceeds the warning value, the fusible plug or safety film ruptures, allowing the high-pressure medium in the container to be discharged. During the normal operation of the refrigeration system, the refrigerant in each pipeline moves in a certain direction. In situations where reverse movement may occur and cause harm, the corresponding pipeline should be equipped with a one-way valve to automatically prevent the reverse flow.