Treatment method for fluorine leakage in pilot freeze dryer

　　Pilot freeze dryer uses physical principles to freeze the moisture in compressed air below the dew point to precipitate it from the air. Limited by the freezing point temperature of water, in practice its dew point temperature can be close to 0 degrees. The dew point temperature of a good pilot freeze dryer is usually around 5 degrees. The intuitive appearance is that the refrigerant pressure gauge is zero.
　　Pilot freeze-drying machine leaking fluorine must first find the leaking point. Checking the leaking point requires patience and a certain way.
　　First, visually inspect the inside of the machine by turning on the machine box, because when the refrigerant is running, there will be compressor lubricating oil mixed in. If there is leakage of freon, it will bring out the smooth oil, then carefully observe the inside of the machine. A sheet of oil stains is probably the leak.
　　Then check whether the capillary copper tubes inside the machine, that is, those thin copper tubes and process tubes less than 6 mm, are broken.
　　After passing the above basic review, mark the doubtful places. Then, it is necessary to confirm the leakage point by filling inert gas with a certain pressure. If there is a premise, it is better to use nitrogen to maintain the pressure. If there is no nitrogen, use gaseous freon. It is strictly forbidden to use oxygen to maintain the pressure.
　　When maintaining the pressure, start to take part in the gas slowly, observe the gauge pressure of the refrigerant in the Pilot freeze dryer while pressurizing, and temporarily end when pressurizing to about 0.2Mpa, then carefully listen for the sound of air leakage inside the machine, if there is You can find the leak by pressing the sound. If not, continue to pressurize to 0.4-0.5Mpa. At this time, find a sponge dipped in soapy water, check in the doubtful place, and then check all the connections inside the machine. If there are leaks, bubbles will blow out, and this process needs to be very careful.
　　If the leak is still not found by the above method, it is likely that the leak is in the evaporator. First of all, it must be confirmed that it can be confirmed by disconnecting the evaporator and the refrigeration system, and then holding the pressure separately. If the pressure drop is invented after holding the pressure alone, it can be confirmed.
　　After finding the leak point of the Pilot freeze dryer, the leak is repaired. According to the difference of the leak point, as long as the leak point is tightened accordingly, if it is a copper pipe welding type leak point, you need to use brazing. Brazing leak repair is a common technique in the refrigeration maintenance industry. The so-called brazing is to use oxygen and acetylene flame to heat.