Monday, February 14, 2011

【 Weak current College 】 refrigeration oil selection and cautions 】

1. refrigeration oil selection principles 1, depending on the compression type to choose the compressor lubricating oil freezer has a piston, screw and centrifugal three types, the first two lubricating oils and compressed refrigerant direct exposure, taking into account the lubricant and the interplay between the refrigerant. Centrifugal oil used is used to lubricate the rotor bearings, according to the size of the load and speed or selection N32. turbine oil N46 2, according to the type of refrigerant selection of lubricating oil and lubricant for refrigerant direct contacts, to consider the interplay between the two. As a class of freon refrigerant can be dissolved in mineral oil, thus chosen lubricant viscosity grade, should be better than using insoluble high a level of refrigerant to prevent oil is diluted does not guarantee that the lubrication. Also note that mixed with a small amount of oil in the refrigerant will not affect the work of the refrigeration system. Refrigeration oil of freezing point is to check the oil in the refrigerant is mixed on whether the precipitation of wax crystals jams refrigeration system quality indicators. 3, according to the choice of refrigerant evaporating temperature lubricating oil in General, the refrigerant evaporating temperature low freezer should use solidifying point lower refrigeration oil, lest the refrigerant in the refrigeration system with a lubricant condensation in the throttle and the evaporator, the impact of refrigeration efficiency. Use ammonia as a refrigerant in the refrigeration, freezing of the lubricant should be lower evaporation temperature. Made with freon refrigerants, lubricants of freezing point may be slightly higher than the evaporation temperature. 4, the working conditions under refrigeration lubricant selection of large and medium-sized multi cylinder, high-speed (piston average speed 3m/s and over), load a large freezer should use viscosity larger VG46 or VG68 or VG100 refrigeration oil. Exhaust gas temperature at 145 ° c or higher load freezer use VG68 or VG100 refrigeration oil. Small, micro-or low-speed (piston average speed not higher than 2m/s) freezer available VG22 or VG32 refrigeration oil. 2. refrigeration oil usage considerations 1. selected oils, lubricating oils, flash point than the freezer of the exhaust gas temperature high 25 ~ 30 ℃. 2. refrigeration oil shall not be mixed in the animal and vegetable oils. As a result of animal and vegetable oil and coolant generates sediment, clogging recycling line. 3. use, when refrigeration oil viscosity decrease 15%, a significant change in the color should be replaced in a timely manner. Or to work time and acid value change to limits: General compressors or freezer bearing lubrication system, the year 1000 ~ 2000 hour oil change, oil change values for the limits to the acidic 0.3 ~ 0.45 mg KOH/g. 4. before changing the new oil, lubricating oil drop in old, carefully clear set net tank of oil and impurities, clean, and then join the new oil

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