Leak Detection Method for Large Chillers
The tightness of the chiller system is usually an important indicator to measure the quality of the installation or manufacture of the refrigeration unit. Because the leakage of the chiller system not only causes the leakage of refrigerant or the infiltration of outside air, which affects the normal operation of the refrigeration unit, but also causes economic losses and pollutes the environment.
However, due to the large number of welding points and connectors in the installation or assembly process of the large-scale chiller system, leakage is inevitable, which requires the commissioning personnel to carefully check the system for leakage, and find and eliminate each leakage point. System leak detection is the main item in the whole debugging work, which must be carried out seriously, responsibly, carefully and patiently.
Leak detection method for large chillers
The pressure leak detection of the refrigeration system of large-scale chillers is the most effective method to check and find leaks. The leak-detection pressure in the refrigeration system of large-scale chillers is related to the type of refrigerant used, the cooling method of the refrigeration system of the chiller and the position of the pipe section. For high pressure systems, the leak detection pressure should be approximately 1.25 times the design condensing pressure; for low pressure systems, the leak detection pressure should be approximately 1.20 times the saturation pressure under summer temperature conditions. In this way, the refrigeration unit can prevent leakage of refrigerant whether it is running or stopped. For some refrigeration systems, if there are predetermined acceptance or leak detection standards, the leak detection should be carried out according to the specified pressure. Obviously, the leak detection pressure cannot be increased arbitrarily, otherwise it may damage the equipment and cause an accident.
The leak detection pressure in the refrigeration system of large-scale chillers should be gradually increased. For every 0.2 MPa~3 MPa increase, the leak-prone parts should be checked once. Once a leak is found, the pressure increase should be stopped immediately. The high pressure gas at the leak site should be released. Especially in the case of repair welding, high-pressure gas must be released, and welding must not be performed under high-pressure conditions to avoid accidents.
For ammonia systems, a refrigeration compressor can be used to gradually increase the system pressure; for Freon systems, nitrogen or dried air should be used to increase the pressure to prevent moisture in the air from being brought into the system.
