Requirements for adding refrigerant to industrial chiller system

　　【】After the industrial chiller system has passed the vacuum test, the vacuum state in the system can be used to charge the refrigerant.

　　1. Refrigerant charging

　　 For a newly installed system, refrigerant can be added to the high-pressure end. The operation method is as follows:

　　 1) Turn on condensation The cooling water system for the device, the valve in the system maintains the state during the vacuum test.

　　2) Connect the steel cylinder containing the refrigerant with a West 14mm×2mm seamless steel tube (use a copper tube when filling with Freon). The mouth of the bottle is inclined downward, and the cylinder is at an angle of 30° with the ground, or the end of the cylinder is raised about 200-300mm.

　　3) Open the filling valve. When the system reaches a certain pressure (0.1～0.2MPa for ammonia system; 0.2～0.3MPa for Freon system), stop charging the refrigerant, and then check the sealing condition of the system at each connection and welding place. If there is no leakage, It can continue to be charged with refrigerant.

　　4) Close the outlet valve on the reservoir and continue to charge refrigerant. When the cylinder pressure and the pressure in the reservoir reach equilibrium, the outlet valve on the reservoir should be opened.

　　5) Start the refrigerating machine, make the refrigeration device enter the operating state, and continue to charge the refrigerant at the same time. When white frost appears in the lower part of the cylinder, it means that the liquid refrigerant in the cylinder is almost completely filled. At this time, the cylinder valve and charging valve can be closed, and the cylinder can be changed to continue charging.

　　6) Unless the outside temperature is very low, it is generally not necessary to pour hot water on the cylinder to increase the pressure in the cylinder when charging the refrigerant, because it is not safe to do so. If you need to speed up the filling speed, the hot water temperature must not exceed 50°C and other methods to heat the cylinder are strictly prohibited.

　　7) When filling freon, a filter drier must be installed on the special nozzle to reduce the possibility of water entering the system. When charging with high pressure section, never start the compressor, and pay attention to the exhaust valve not to leak, otherwise it will cause liquid shock.

　　8) When the refrigerant is charged up to 90% of the charge amount, the charging work can be temporarily stopped, and the system can be tested to check whether the system dosage has met the operation requirements and avoid excessive charging. unnecessary trouble. For the old refrigeration system, when the refrigerant needs to be supplemented, it should be charged from the low pressure side.

　　2. Leak detection after filling

　　(1) Test paper leak detection method generally uses phenolphthalein test paper to test the system's welds, flanges, threaded interfaces, etc. . Wet the test paper and approach the inspected place. If it turns red, it means that there is ammonia leakage (note that the test paper should not be in contact with the soapy water on the pipe to create an illusion). Litmus paper that turns blue when exposed to ammonia can also be used.

　　(2) Halogen blowtorch leak detection method Halogen blowtorch is a common tool for leak detection in Freon refrigeration systems. The domestic halogen blowtorch is shown in the figure below. The method of use is as follows:

　　1, add Alcohol: First unscrew the base 1 and add anhydrous alcohol with a purity of not less than 99.5% to the inside of the barrel, but the amount of injection should not be too much, just fill 1/2 to 3/4 of the volume of the lamp tube The base should be quickly tightened afterwards.

　　2, light a fire: turn the handwheel 2 to the right, close the valve core, fill the wine glass, and then ignite it to heat the lamp tube and the upper part of the blowtorch. After heating a little, check whether the blowtorch is leaking .

　　3. Ignite: When the alcohol in the beaker is about to burn out, turn the handwheel 2 to the left and ignite the volatilized alcohol in the nozzle in the flame circle 4. At this time, the halogen lamp is sucked The gas hose 6 emits the sound of gas inhalation, and the lamp can be used for leak detection.

　　4. Use: When testing, move the nozzle of the suction hose 6 close to the inspected place and move slowly. If there is Freon gas leakage, it will decompose when it meets the flame. At this time, the orange-red flame will be It will turn green, and the flame color changes with the amount of Freon leakage. The darker the color, the more serious the Freon leakage.