How to supplement and discharge refrigerant in cold storage refrigeration system

How to supplement and discharge refrigerant in cold storage refrigeration system

The cold storage refrigeration system must ensure that the refrigerant is dry when adding refrigerant (only applicable to fluorine refrigerant refrigeration systems), otherwise the refrigeration system will definitely cause ice blockage in the refrigeration system due to the non-drying of the refrigerant, thereby affecting the normal operation of the refrigeration system , Let’s explain in detail the charging and discharging of refrigerant in the fluorine refrigeration system.

When the refrigeration system is replenishing refrigerant, it is necessary to close the outlet valve of the condenser or accumulator, vacuum the infusion pipe and the low-pressure system, shut down, close the exhaust valve, and slightly open the outlet valve to return the pressure of the low-pressure system to 0MPa .

　　 Remove the desiccant filter, replace it with a new desiccant and reinstall it, vacuum the infusion pipe and the low-pressure system again, then open the exhaust valve, outlet valve, stop valve, start the compressor, and exercise for several hours.

　　 Repeat the above operation, check and replace the desiccant until there is no moisture in the refrigerant.

　　 Refrigerant supplement

　　 1. The system replenishes ammonia. Ammonia systems are generally equipped with an ammonia addition valve for supplementary ammonia. When adding liquid, first close the liquid supply valve from the reservoir, intercooler, and drain on the main regulating station, start the compressor, reduce the pressure of the evaporation system, open the ammonia bottle valve, the ammonia valve, and the ammonia liquid passes through the adding The liquid pipe enters the evaporator and the circulating accumulator, is sucked by the compressor, and finally enters the accumulator. During the liquid filling process, the safety operation regulations of the equipment must be followed, and the liquid storage volume of the liquid reservoir after liquid filling shall not exceed 80% of the volume of the liquid reservoir.

　　 2. Systematic replenishment of fluorine compounds. Large and medium fluorine compound systems generally have a filling valve on the high pressure side. During the filling operation, the filling pipe is connected to the refrigerant cylinder and the filling valve, after removing the air in the filling pipe, tighten the connecting nut, then close the liquid supply valve of the accumulator, and open the filling valve to make the refrigerant in the cylinder close The pressure difference and height difference enter the system by themselves. When adding liquid, a scale should be used for measurement, and the liquid level indicator on the reservoir should be observed to control the amount of liquid added. The small fluorine compound system does not have a liquid filling valve, and can only be used to supplement the refrigerant through the compressor suction valve multi-purpose channel or the process tube when the machine is turned on. In order to avoid the “frost" caused by the compressor, the opening degree of the refrigerant cylinder valve must be controlled to ensure that the refrigerant gas is sucked in. The control of the replenishment amount should be weighed and calculated, or analyzed and judged from the operating status of the refrigeration system .

　　 Emission of refrigerant

　　 When the refrigeration system is undergoing equipment overhaul, the refrigerant should be discharged from the system into the liquid storage cylinder. There are two methods as follows:

　　Large, medium-sized equipment can be connected to the empty steel cylinder through the system's filling valve. After the cylinder is evacuated, the pressure difference of the accustomed steel cylinder is used to make the refrigerant liquid in the accumulator flow into the cylinder. Place the steel cylinder on the scale during the dispensing process, and always pay attention to the quality of the refrigerant added to the cylinder not to exceed the allowable filling volume.

A small system can use its own compressor or borrow another compressor to extract the refrigerant. During operation, the compressor exhaust pipe or exhaust valve is connected to the cylinder with multiple channels, and tap water is continuously poured outside the cylinder to start the compressor. , The refrigerant in the system is pressed into the cylinder and cooled into liquid. Pay attention to control the discharge pressure during operation. If necessary, close the compressor suction valve to reduce the discharge pressure.