SF6 gas, as an insulating gas, is non-toxic, non flammable, and has good insulation properties. Its insulation strength is much higher than traditional insulating gases, and it has good arc extinguishing properties. Therefore, it is widely used in SF6 electrical appliances. Due to the high price of SF6 gas and the decomposition of toxic components under the action of electric arc, spark and corona discharge. Therefore, SF6 gas needs to be recovered when applying SF6 electrical equipment. This device is a specialized equipment for the recovery and filling of SF6 gas during the manufacturing and maintenance of SF6 electrical equipment.

1YH7Y-55 SF6 gas recovery charging and discharging deviceIt has comprehensive functions such as recycling, filling and discharging, purification, vacuuming, storage, and bottle filling. The system is relatively complete, as shown in Appendix 1 System Diagram. The series connection or switching of various functions is mainly achieved by operating the control box and ball valve concentrated on one side of the panel.
2. The basic working principle of the recycling device is to use the freezing liquefaction method. During recycling, the suction and compression properties of the compressor are utilized to draw SF6 gas at a certain pressure into the SF6 electrical equipment and compress it to a higher pressure. At the same time, utilizing the low evaporation temperature characteristics of R22 refrigerant, SF6 gas at higher temperatures is cooled to the condensation temperature for liquefaction and storage. Continuously suction until the SF6 compressor runs in series until the final recovery pressure is reached.
3. When charging and discharging, first use the vacuum pump of this device to evacuate the SF6 electrical equipment (or steel cylinder) and connecting pipelines, and then directly use the pressure difference or the suction ability of the compressor to create a certain pressure difference to charge the SF6 in the storage container of the device into the SF6 electrical equipment until the required working pressure is reached. When filling the cylinder, utilize the characteristics of R22 refrigerant as described earlier to directly inject liquefied SF6 into the cylinder.
4. The purification function is completed synchronously with the above-mentioned recycling and charging functions.
5. Three oil separators are installed in the system, one at the outlet of the vacuum pump and two at the outlet of the compressor, to effectively remove the oil carried by SF6 gas.
6. A dry filter is installed in the system circuit 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 repeatedly.
7. The system is equipped with reliable safety protection devices, and the high-pressure controller is installed at the exhaust port of the SF6 compressor. Once the exhaust pressure exceeds the limit value, it will automatically stop the operation of the compressor and restart it after the pressure drops; Once the safety valve is installed on the storage container and exceeds the pressure, it will automatically open to discharge gas and close automatically when the pressure drops.
8. In addition, the system is equipped with seven monitoring and control instruments, including one vacuum gauge installed at the device's recovery inlet. A DN8 valve is also installed in front of the vacuum gauge, which can be opened when observation is needed; Five pressure gauges are installed on the recycling inlet, SF6 compressor exhaust outlet, refrigeration compressor suction and exhaust outlet, and storage container respectively; A thermometer is installed on the refrigeration system, which uses a temperature sensor to sense the temperature of SF6 liquid.
9. The inlet of the vacuum pump in the system is equipped with an electromagnetic vacuum belt inflation valve, which is connected to the same power source as the vacuum pump. When the pump stops working, the valve can automatically seal the vacuum system and fill the pump chamber with atmosphere through the inlet of the pump, thereby avoiding pump oil backflow and pollution of the vacuum system.
10. The refrigeration system in the system is set by a high and low pressure controller to regulate the inlet and outlet pressures of the refrigeration compressor. Once the limit range is exceeded, the operation of the refrigeration compressor will be automatically cut off. When the low pressure is disconnected, wait for the pressure to rise or when the high pressure is disconnected. After the pressure drops, restart the compressor.
11. Overall structure, the device adopts a hand push mobile type, which can adapt to normal indoor and outdoor environmental conditions for use. This device system is quite complex, consisting of a vacuum pump, SF6 compressor, refrigeration system, storage container, pipeline, various valves, instruments, and other accessories.
12. The electrical control box, operating valves, and monitoring instruments are all centralized on one side panel with process instructions, making them easy to use and clear.

1. Recycling
Recovery initial pressure ≤ 0.8MPa
Recovery final pressure ≤ 50KPa
Recovery time: For a 1 m3 SF6 gas volume with an initial pressure of 0.8 MPa, recover to a final pressure of 50 KPa, with a recovery time of less than 2.5 hours.
2. Inflate
Fill the volume of 1 m3 SF6 gas with an initial pressure of 133Pa to 0.8MPa, and the filling time should be less than 0.8 hours.
3. Vacuum pumping
The maximum vacuum degree of the device is less than or equal to 10 Pa
The time required to evacuate a 1 m3 SF6 gas volume with an initial pressure of 0.1 MPa to 133 Pa is less than 1.0 hour.
4. Storage
Storage container capacity 0.015m3
Nominal liquid storage capacity 50kg
Maximum storage pressure 3.8 MPa
5. Purification
For SF6 gas with a water content of less than 1000PPM (volume ratio), after a single recovery and purification by this device, the water content is less than 60PPM (weight ratio) and the oil content is less than 10PPM (weight ratio)
6. Annual leakage rate ≤ 1% nominal storage capacity
7. Noise ≤ 75dB (A) Sound pressure level
8. Working environment temperature -10 ° C to 40 ° C
9. Power ≤ 5KW
10. Power supply: AC three-phase five wire system 50HZ 380V ± 10%
11. Weight approximately 600 kg
12. Dimensions (length x width x height): 1360 x 800 x 1300

The SF6 gas recovery and filling device has comprehensive functions such as recovery, filling and discharging, purification, vacuuming, storage, and bottle filling. The system is relatively complete, as shown in Appendix 1 System Diagram. The series connection or switching of various functions is mainly achieved by operating the control box and ball valve concentrated on one side of the panel. The basic working principle of the recycling device is to use the freezing liquefaction method. During recycling, the suction and compression properties of the compressor are utilized to draw SF6 gas at a certain pressure into the SF6 electrical equipment and compress it to a higher pressure. At the same time, utilizing the low evaporation temperature characteristics of R22 refrigerant, SF6 gas at higher temperatures is cooled to the condensation temperature for liquefaction and storage. Continuously suction until the SF6 compressor runs in series until the final recovery pressure is reached.
When charging and discharging, first use the vacuum pump of this device to evacuate the SF6 electrical equipment (or steel cylinder) and connecting pipelines, and then directly use the pressure difference or the suction ability of the compressor to create a certain pressure difference to charge the SF6 in the storage container of the device into the SF6 electrical equipment until the required working pressure is reached. When filling the cylinder, utilize the characteristics of R22 refrigerant as described earlier to directly inject liquefied SF6 into the cylinder.
The purification function is completed synchronously with the above-mentioned recycling and charging functions.
Three oil separators are installed in the system, one at the outlet of the vacuum pump and two at the outlet of the compressor, to effectively remove the oil carried by SF6 gas.
A dry filter is installed in the system circuit 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 repeatedly.
The system is equipped with reliable safety protection devices, and the high-pressure controller is installed at the exhaust port of the SF6 compressor. Once the exhaust pressure exceeds the limit value, it will automatically stop the operation of the compressor and restart it after the pressure drops; Once the safety valve is installed on the storage container and exceeds the pressure, it will automatically open to discharge gas and close automatically when the pressure drops.
In addition, the system is equipped with seven monitoring and control instruments, including one vacuum gauge installed at the device's recovery inlet. A DN8 valve is also installed in front of the vacuum gauge, which can be opened when observation is needed; Five pressure gauges are installed on the recycling inlet, SF6 compressor exhaust outlet, refrigeration compressor suction and exhaust outlet, and storage container respectively; A thermometer is installed on the refrigeration system, which uses a temperature sensor to sense the temperature of SF6 liquid.
The inlet of the vacuum pump in the system is equipped with an electromagnetic vacuum belt inflation valve, which is connected to the same power source as the vacuum pump. When the pump stops working, the valve can automatically seal the vacuum system and fill the pump chamber with atmosphere through the inlet of the pump, thereby avoiding pump oil backflow and pollution of the vacuum system.
The refrigeration system in the system is set by a high and low pressure controller to regulate the inlet and outlet pressures of the refrigeration compressor. Once the limit range is exceeded, the operation of the refrigeration compressor will be automatically cut off. When the low pressure is disconnected, wait for the pressure to rise or when the high pressure is disconnected. After the pressure drops, restart the compressor.
Overall structure, the device adopts a hand push mobile type, which can adapt to normal indoor and outdoor environmental conditions for use. This device system is quite complex, consisting of a vacuum pump, SF6 compressor, refrigeration system, storage container, pipeline, various valves, instruments, and other accessories.
The electrical control box, operating valves, and monitoring instruments are all centralized on one side panel with process instructions, making them easy to use and clear.

1. Attention points
Please pay attention to the following points before starting up:
The pipeline connection should ensure the sealing of the connection.
Due to the fact that this device has already been vacuumed at the factory, it is recommended to first evacuate the device when it is first turned on. Please refer to the relevant content in Section 5 for the method. After the first start-up, a small amount of SF6 gas should generally be left in the storage container and pipeline, otherwise it is recommended to vacuum again when starting up.
2. Pipeline connection
Before use, users should first connect the randomly sent rubber hoses according to their functional needs. To minimize pipeline losses, the pipeline should be as short as possible.
Recycling: Electrical equipment - Rubber hoses - Recycling air inlet
Charging and discharging: Electrical equipment - Rubber hose - Charging and discharging gas (liquid) outlet
Two flexible hoses are required for SF6 recycling and filling of electrical equipment bottles:
Electrical equipment - Rubber hoses - Recycling air inlet
Steel cylinder - rubber hose - filling and discharging gas (liquid) port
SF6 filling bottle in storage container:
Steel cylinder - rubber hose - filling and discharging gas (liquid) port
In addition to the recycling air inlet and the filling and discharging air (liquid) outlet, the equipment also has an exhaust air outlet, and the user can decide whether to connect the pipeline according to their needs.
3. Oil level check
The compressor in the recycling device uses N46 (25 #) refrigeration oil as lubricant, and the vacuum pump uses high-speed vacuum pump oil as lubricant. The oil level should be checked before starting up. If the oil level is too low or too high, oil should be added or drained to the center position of the oil level gauge. During operation, attention should also be paid to regularly checking the actual oil level line, which should not be too much lower than the center line. N46 refrigeration oil, in principle, has a service life of one year. When it expires, the oil needs to be replaced. The oil consumption can be found in the relevant content of Section 2, and the oil replacement method can be found in the relevant content of Section 6.
4. Freezing system inspection
The refrigeration system uses R22 as the refrigerant, and the compressor is a fully enclosed piston compressor. If necessary, refrigerant can be added. Before starting up, it is also necessary to check whether the circuit is damaged, whether the joints are loose, whether the fan is normal, and so on.
5. Power connection
The power supply of this device is three-phase AC 50HZ 380V ± 10%, with a total power of ≤ 7KW. All electrical control components of the device are centralized in the electric control box, and the electrical circuit diagram can be found in Appendix 5 Electrical Schematic Diagram and Appendix 6 Electric Control Box Component Layout Diagram. Due to the installation of buttons, switches, and indicator lights on the door of the electrical control box, the box does not need to be opened during normal operation. Please refer to Appendix 7 for the operation panel diagram of the electrical control box. Simply connect the power cable plug placed next to the storage container of the recycling device to an appropriate power source. Before starting up, the power switch of the electrical control box can be turned on to enter the working state. At this time, follow the instructions in Section 5.
There are phase failure and phase sequence protection relays in the electrical circuit, which can manually adjust the phase sequence of the power supply. There is a timer above the electrical control box, which automatically records the time when the vacuum pump, SF6 compressor, or pump is turned on simultaneously.