Cold storage compressor shaft seal leakage determination and replacement | shaft seal structure, oil and fluorine leakage, installation precautions
The semi closed piston compressor is equipped with a shaft seal at the extended position of the main shaft, which isolates the refrigerant and refrigerant oil inside the crankcase to prevent refrigerant leakage and refrigerant oil leakage. It is a vulnerable seal.
There are two types of shaft seal leakage: slight oil leakage and refrigerant leakage; Only oil leakage, with minimal fluoride leakage; The oil and refrigerant are running out together, which is due to the failure of the shaft seal sealing surface and needs to be replaced.
The shaft seals of Xitelidou small four cylinder and medium four cylinder piston engines are standard accessories, and the maintenance spare parts package comes with shaft seal components as standard. It is recommended to prepare sufficient spare parts of the same specifications for overseas projects.
Causes of shaft seal failure: long-term start stop impact, wear of sealing surface due to impurities in refrigeration oil, frequent liquid hammer of compressor, increased bearing clearance, spindle jumping, and wear of dynamic and static rings.
Determine the leakage point of the shaft seal: After the compressor stopped, there were continuous oil stains at the shaft seal position. The electronic leak detector detected a refrigerant signal at the shaft seal position and ruled out other joint leakage points.
After replacing the shaft seal, many maintenance technicians fail to clean the burrs and scratches on the surface of the spindle, and the newly installed shaft seal quickly wears out again, resulting in repeated leakage in a short period of time.
Replacing the shaft seal requires the recovery of refrigerant and pressure relief, and cannot be disassembled under pressure; Lubricate the sealing surface during assembly, use original matching refrigeration oil, and prohibit the use of other oils for lubrication.
Screw compressor shaft seals have higher pressure and faster speed, and the difficulty of replacing shaft seals is higher than that of piston machines. Many screw machines do not have maintenance conditions on site and are directly returned to the factory for processing.
The shaft seal is slightly leaking oil. If there is no obvious refrigerant leakage and the oil level is stable, it can be observed for a short period of time; Once accompanied by refrigerant leakage, it is necessary to shut down and replace as soon as possible to avoid continuous oil shortage.
Foreign trade projects often encounter unstable voltage and frequent start stop of units, which can shorten the service life of shaft seals. Technical briefings remind customers that the inspection cycle of shaft seals under such working conditions can be shortened by half.
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FAQ
What is the function of the shaft seal? Seal the main shaft to prevent refrigerant and refrigeration oil from leaking outward.
What are the two types of shaft seal leakage? Simple oil leakage, oil+refrigerant leakage together.
Can the replacement of the shaft seal be operated under pressure? The refrigerant must be recovered and depressurized before disassembly.
What would happen if there are scratches and burrs on the spindle and a new shaft seal is installed directly? The new shaft seal quickly wears out and leaks again.
5. Is it difficult to repair the shaft seal of the screw machine? High speed, difficult on-site maintenance, and frequent return to the factory.
6. Should I replace it immediately if it only leaks oil and not fluorine? Stable oil level can be observed in the short term.
Why is the shaft seal prone to breakage when frequently started and stopped? The spindle repeatedly impacts, accelerating the wear of the sealing surface.
