2205B0JE-DA-J-N_2014.05.
4 Compressor and Package Operation
Screw Compressor J-series
4.2 Lubricant (Refrigerant Oil)
4-2
4.2
Lubricant (Refrigerant Oil)
The selection and management of lubricant (refrigerant oil) has a significant influence to the
compressor performance
When selecting and managing lubricant, take the following points into consideration
4.2.1 Precautions for Selecting the Lubricant
The lubricant must be selected while considering the refrigerant in use, type of evaporator, and
operation conditions. Various properties of lubricant must be checked such as solubility with
the refrigerant, separability, fluidity at low temperature and thermal stability at high temperature
as well as viscosity. We therefore recommend consulting our sales offices or Mayekawa
agencies for choice of a specified brand for your system.
The lubricant supplied to the compressor must have appropriate proper viscosity to lubricate
bearings and other mechanical components. The lubricant viscosity must be measured at the
oil supply port of the compressor. The viscosity of lubricant is significantly affected by the type
of refrigerant and oil. If the refrigerant dissolves in oil (the oil is miscible), the actual viscosity
may be substantially lower than the required viscosity for the compressor depending on the
operation conditions. If the refrigerant does not dissolve in the oil (the oil is not miscible) and
the oil temperature is low, the viscosity may become excessively high. The lubricant must be
selected such that it is supplied to the compressor with appropriate viscosity (13 to 40 mm
2/
s)
in the operating conditions.
In a system utilizing a screw compressor, the lubricant supplied to the compressor is
discharged along with the gas and separated from the refrigerant gas by the oil separator.
However, the oil separator cannot separate all the oil from refrigerant gas and a small quantity
of the lubricant goes to the condenser. As a results oil also enters the evaporator. Because of
the wide operation temperature range of the lubricant, it must have thermal stability at high
temperatures, good fluidity at low temperatures as well as high separable performance from
refrigerant gas in the oil separator.
Depending on the refrigerant in use, some lubricants cannot be used. For example, polyolester
(POE) cannot be used with ammonia refrigerant.
4.2.2 Recommended
Lubricant
When selecting lubricant, not only the refrigerant but also O-rings in use must be considered.
We therefore recommend using the following brands of lubricant for the J-series compressors to
prevent any operating problems.
Recommended Lubricant for Ammonia Refrigerant
(1) Polyalkylene glycol synthetic oil (PAG): Miscible oil
Type
Brand
Manufacturer
VG
Recommended
temperature (°C)
PAG
Freol PN46
JX
46
40-50
see Note 1
RPS52 Kluber
46
40-50
see Note 1
(2) Naphthenic base mineral oil: Non-miscible oil
Type
Brand
Manufacturer
VG
Recommended
temperature (°C)
M
Suniso 3GS
Sun Oil
32 35-60
Suniso 4GS
68
50-60
Gargoyle Arctic 155
Exxon Mobil
32 35-60
Gargoyle Arctic C Heavy
46
45-60
Gargoyle Arctic 300
68
55-60
Capella WF32
Texaco
32 35-60
Capella WF46
46
45-60
Capella WF68
68
55-60
