How to deal with the problem of refrigerant leakage from the freeze dryer?

The leak detection point requires patience and carefulness and a certain method. The specifics are as follows: first use the visual method to open the box of the machine to observe the inside of the machine, because the refrigerant will be compressed when it is running.

The lubricating oil is mixed in the machine. If the Freon leaks, the lubricating oil will be brought out. Then carefully observe the inside of the machine. If there are flaky oil stains, it is likely to be the leaking point and then check The capillary copper tubes inside the machine, that is, those thin copper tubes and craft tubes below 6 mm, are there any breakages? After passing the above basic inspections, mark the suspected areas.

Next, you need to fill in a certain pressure of inert gas to confirm the leak. If conditions permit, 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. Check for leaks, that's death. What is gaseous freon? Brother doesn't know this. It is to put the freon cylinder upright, and the gaseous freon comes out from the upper shut-off valve. On the contrary, put the cylinder shut-off valve downwards and it is liquid freon. The intuitive appearance of z* is that the refrigerant pressure gauge is zero. Fluoride leakage s* must first find the leakage point. When maintaining the pressure, add gas slowly at the beginning, and observe the pressure of the refrigerant gauge of the refrigeration dryer while pressurizing (the small cube has only a refrigerant low pressure gauge, and 15 cubic meters or more have two high and low pressure refrigerant gauges) when the pressure reaches about 0.2Mpa2.0kgf Stop temporarily, and then listen carefully to see if there is any air leakage inside the machine. If there is, you can find the leak according to where the sound is. If not, continue to pressurize to 0.4-0.5Mpa. At this time, find a sponge and dip it in soapy water. Check the suspected areas first, and then check all the connections (copper nuts) inside the machine.

If the leak is still not found through the above method, then unfortunately, it is very likely that the evaporator leaks and it is troublesome to handle the evaporator leak. s* must be confirmed first. It can be confirmed by disconnecting the evaporator and the refrigeration system, and then maintaining the pressure separately. If the pressure is found to decrease after the pressure is maintained separately, it can be confirmed.

There is also a relatively simple method, which is to open the compressed air inlet. If the pressure of the refrigerant pressure gauge rises after a period of time, it can be sure that the refrigeration system is connected to the air system because of the exchange of w* The part is the evaporator. Therefore, the internal leakage of the evaporator can also be determined.

After checking the leaking points of the dryer, it is to make up for the leaks. According to the difference of the leaking points, to loosen the leaking points of the bell mouth, just use the wrench to do the corresponding tightening. If it is a copper pipe welding type leak Point, you need to use brazing. Brazing is a common skill in the refrigeration and maintenance industry. The so-called brazing is to use oxygen and acetylene flame to heat the low-silver electrode and repair it.

Welding part, let the welding rod and repair welding part fuse together to make the leaking point plugged. When brazing, the pressure of the refrigeration system should be vented to zero, and then use the brazing torch to turn on the acetylene first, add oxygen appropriately after lighting, and slowly adjust the ratio of oxygen to acetylene to make the flame a neutral flame-oxidation flame, and then heat The required welding part and the silver electrode make the two melt together. The specific method requires the operator to pass certain training to master. After the leaks are processed, the system needs to be pressure-maintained again to confirm whether the leak repair welding is successful.

After the leak is completed, the system needs to be evacuated, and then the specified quality liquid Freon (refer to the basic configuration table for the specific quantity) plus the refrigerant should be reserved from the refrigeration dryer

Some Add liquid needle valve to join. For larger machines, fluoride should be added from the high-pressure filling port first. If the prescribed dose cannot be filled at one time, add fluoride slowly from the low-pressure port to the prescribed dose after the machine is turned on.