SF6 Recovery and Refilling Device Parameters
It has comprehensive functions such as recovery, charging and discharging, purification, vacuum pumping, storage, and cylinder filling. The system is relatively complete; refer to Appendix I for the system diagram. The series connection or switching of each function is mainly accomplished through the electric control box and ball valves concentrated on one side of the panel.
The basic working principle of the recovery device is to use the freezing liquefaction method. During recovery, the suction and compression properties of the compressor are used to draw SF6 gas at a certain pressure from SF6 electrical equipment into the compressor and compress it to a higher pressure. At the same time, utilizing the low evaporation temperature characteristics of R22 refrigerant, the higher-temperature SF6 gas is cooled to the condensation temperature for liquefaction and storage. This continuous suction is carried out until the SF6 compressors operate in series until the final recovery pressure is reached.
During charging and discharging, first use the vacuum pump of this device to evacuate the SF6 electrical equipment (or cylinders) and connecting pipelines, then directly use the pressure difference or use the suction of the compressor to create a certain pressure difference to fill the SF6 from the device's storage container into the SF6 electrical equipment until the required working pressure is reached. When cylinder filling is needed, the aforementioned characteristics of R22 refrigerant are also utilized to directly fill the liquefied SF6 into cylinders.
The purification function is completed simultaneously with the above recovery and charging/discharging functions.
Three oil separators are installed in the system, one at the outlet of the vacuum pump and two at the outlets of the compressors, to effectively remove the oil carried by the SF6 gas.
Dry filters are installed in the system loop to ensure the purity of SF6 entering the storage container and effectively remove moisture. The filter is equipped with a heating regeneration device, which can be heated and regenerated under vacuum, allowing the molecular sieve to be reused.
