Refrigerant filling operation method of centrifugal chiller

Refrigerant filling operation method of centrifugal chiller The centrifugal chiller refrigeration compressor after completing the work procedure of filling the frozen lubricating oil, the next step should be the refrigerant filling operation, the method of operation is: (1) using copper pipes or PVC (polyvinyl chloride) pipes One end is connected with the filling valve at the lower part of the evaporator, and the other end is connected with the top joint of the refrigerant storage tank to ensure good sealing. (2) A dryer should be added to the middle of the fluorine pipe (copper pipe or PVC pipe) to remove the moisture in the refrigerant. (3) The lubricating oil in the oil tank should be heated to 50～60℃ before charging the refrigerant. (4) If the refrigerant is charged when the refrigeration compressor is stopped, the refrigerant water pump of the evaporator can be started (to speed up the filling and prevent the static water in the pipe from freezing). During the initial irrigation, the unit should have a vacuum of 0.866 105Pa or more. (5) With the progress of the filling process, the vacuum in the unit decreases and it is difficult to inhale (when the refrigerant has immersed more than two rows of heat transfer tubes), the cooling water pump can be started, and the compressor can be operated according to the normal starting operation procedure (The opening degree of the inlet guide vane is 15%-25%, avoiding the surge point, but the opening degree should not be too large), keep the vacuum degree of 0.4, 105Pa in the unit, and continue to suck the refrigerant to the specified value. In the process of refrigerant filling, when the vacuum in the unit is reduced and it is difficult to suck, the method of lifting the refrigerant steel bottle to increase the liquid level can be used to continue the filling, or the steel bottle can be heated with warm water. But never use an open flame to heat the cylinder. (6) The amount of refrigerant charged should be strictly controlled during the process of refrigerant charging. The filling volume of each unit is indicated on the "Instruction Manual" and "Product Catalog". The initial charge of the unit should be about 50% of the rated value. When the standby group is put into formal operation, supplements will be made according to the boiling situation of the refrigerant in the evaporator. Excessive refrigerant charge at a time will cause liquid to appear in the compressor; the phenomenon will cause the overload of the main motor and the temperature of the compressor outlet to drop sharply. However, the insufficient refrigerant charge in the unit will cause the evaporation temperature (or refrigerant water outlet temperature) to be too low during operation and shut down automatically.