In practical applications, we may all encounter refrigerant leaks, but when we encounter this situation, how should we deal with it correctly and quickly? Here are the steps on how to correctly deal with leaks in ammonia refrigeration systems.
1. Operation of condenser
When the refrigeration system is running, except for the oil drain valve and air drain valve that are closed, all other valves of the condenser should be open. The condensation pressure of the water-cooled condenser should not exceed 1.5MPa (for reference), otherwise the cause should be identified and eliminated in time. Only after all compressors are shut down can the water supply to the condenser be stopped. When stopping work for a long time in winter, the stored water should be drained to avoid freezing the equipment. Always check the temperature and volume of the cooling water. The temperature difference between the cooling water inlet and outlet is about 2-4 degrees Celsius. Generally, the condensation temperature is 3-5°C higher than the cooling water outlet temperature. The dirt on the condenser tube wall must be removed regularly. The thickness of the dirt shall not exceed 1mm, and is generally removed once a year. Oil stains will appear when the fluorine condenser leaks. Condenser leaks should be discovered in time for timely maintenance. The water distributor of the vertical shell and tube condenser should be placed appropriately, the water should be evenly distributed along the inner wall of the pipe, and the water volume should be sufficient. The cooling water of the horizontal shell and tube condenser should flow from the bottom to the top, and the cooling water must not be interrupted during operation. When the evaporative condenser is running, the exhaust fan and circulating water pump should be started first, and then the air burst valve and liquid outlet valve should be opened. The water spray nozzle should be unobstructed, the water spray should be even, and the scale should be cleaned once a year. Air-cooled condensers should often use compressed air to clean the accumulated dust on the tube walls and radiator fins to improve heat transfer efficiency. When multiple condensers are used in combination, it is necessary to determine the number of working condensers, the required cooling water volume, and the number of water pumps to operate. This should be based on parameters such as the load of the compressor and the temperature of the cooling water to achieve an economical, reasonable and efficient refrigeration system. safe operation.
2. Operation of evaporator
Cold room evaporators can be divided into two categories: air coolers and cooling exhaust pipes. Air coolers are generally used in cooling rooms, freezing rooms and cooling and cooling rooms. Depending on the installation location, they can be divided into floor-standing air coolers and ceiling-mounted air coolers. Cooling pipes are often used in frozen food refrigeration rooms, and cooling pipe evaporators are also used in general small refrigerators.
Cooler operation. The air cooler should be in good condition before starting. The anchor bolts of the fan and motor should not be loose. The blades should not rub against the protective cover and the air duct. The rotation should be flexible. The bearings should be well lubricated. During normal operation, the surface of the evaporation coil of the air cooler should be The frosting should be even. If uneven frosting is found, it means that the liquid supply is abnormal. Adjustments should be made, and the liquid supply valve should be opened appropriately to increase the liquid supply volume. If the frost layer is too thick, the fin gaps of the evaporator coil will be blocked by the frost layer, hindering air circulation, reducing heat exchange efficiency, and making it difficult to cool down the cold room. Therefore, when the frost is too thick, the frost should be washed away in time. The air cooler in the freezing room generally needs to be flushed with frost regularly. When the air cooler is stopped, the liquid supply valve should be closed first to stop supplying liquid to the evaporation coil of the air cooler. After the pressure of the evaporation coil drops, the return valve should be closed, the power supply to the fan motor should be cut off, and the operation of the air cooler should be stopped.
Operation of cooling rows. The cooling exhaust pipe is an air natural convection heat exchange evaporator. Except for the operation without a fan, the liquid supply operation procedure is basically the same as that of the air cooler. When the cooling drain pipe is running, first open the air return valve and then slowly open the liquid supply valve to supply liquid to the cooling drain pipe.
When the cooling exhaust pipe is operating normally, the surface of the cooling exhaust pipe should be evenly frosted, and the amount of liquid supply can be determined based on the frosting condition. Too much liquid supply may cause the compressor to have a wet stroke. If there is too little liquid supply, the surface of the discharge pipe will not be completely frosted, affecting the cooling of the cold room. Therefore, the opening degree of the liquid supply valve should be adjusted frequently according to the actual situation. When the frost on the cooling pipe is too thick, the frost should be removed in time to avoid affecting heat exchange.
When there is too much oil accumulated in the cooling pipe, the lubricating oil occupies the space of the liquid pipe and forms an oil film on the inner wall of the cooling pipe, which seriously affects the heat exchange and makes it difficult to cool down the cooling room. At this time, the frost should be removed in time to take the oil out of the cooling drain pipe, or it can be discharged from the specially designed oil drain pipe into the low-pressure oil collector for disposal. (Ammonia system)
