Emulsification of lubricating oil in air compressors refers to the formation of a milky white emulsion after the lubricating oil mixes with moisture and impurities, completely losing its lubricating, heat dissipation, and sealing functions. It is a common hidden fault in screw air compressors. Although it may not directly trigger a shutdown, it can quickly corrode the internal components of the main engine and accelerate the wear of rotors and bearings. In severe cases, it can cause the main engine to seize. Once emulsification is detected, the machine must be shut down immediately for treatment, and one should not take any chances and continue to operate it. The core causes mainly focus on three aspects: water vapor intrusion, equipment operating conditions, and defects in the oil system. Both treatment and prevention must be implemented simultaneously to achieve a radical solution.

The primary cause is the significant infiltration of water vapor into the oil system. During the compression process, air will release condensed water, which would normally be expelled through an oil-gas separator and a drain valve. However, if the drain valve is blocked or malfunctions, the water cannot be promptly discharged and will directly mix with the lubricating oil. Excessive humidity in the machine room and the intake of moist air at the air intake end (such as during rainy seasons, in coastal high-humidity environments, or when the workshop is close to a water source) can significantly increase the moisture content in the intake air, thereby exacerbating the formation of condensed water. Additionally, long-term low-load and low-temperature operation of the air compressor, with exhaust temperatures persistently below 70°C, fails to reach the critical temperature for oil-gas separation and water evaporation. This prevents effective dehydration of the lubricating oil, leading to continuous accumulation of water, which quickly emulsifies. This is also the core reason why emulsification is most likely to occur in air compressors that are used intermittently and turned on for short periods.

Thorough treatment steps: First, immediately shut down the machine, drain all emulsified lubricating oil, and strictly prohibit adding new oil for mixed use; disassemble and clean the oil-gas separator, oil cooler, and oil filter, replace them with brand new oil filters and oil separator cores, unclog and overhaul the drain valve to ensure smooth drainage; start the machine for a period of no-load operation, use the operating temperature of the main engine to dry the residual moisture inside, and then refill with the same type of dedicated screw machine oil. For daily prevention, strictly control the operating temperature, avoid long-term low-temperature no-load operation, regularly check the drain valve and blowdown valve, install an air intake drying device in high humidity environments, shorten the lubricating oil replacement cycle, regularly test the oil quality, identify moisture hazards in advance, and eliminate emulsification problems from the root.