Hanbell RC2-930A - 3. Lubricants

Technical Manual VERSION 2.0 -10-18-2018
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3. Lubricants
The main functions of lubrication oil in screw compressors are lubrication, internal sealing, cooling and capacity control.
Positive oil pressure in the cylinder pushes the piston together with the slide valve that is connected by a piston rod to
move forward and backward in the compression chamber. The design of positive pressure differential lubrication
system makes RC2 series normally omit an extra oil pump which is necessary for reciprocating compressors. However,
in some special applications, it is still necessary to install an extra oil pump to screw compressors for safety.
Bearings used in RC2 series compressors require a small and steady quantity of oil for lubrication. Oil injection into the
compression chamber creates a film of oil for sealing in the compression housing to increase efficiency and also can
dissipate part of compression heat. In order to separate oil from refrigerant gas, an oil separator is required to ensure
the least amount of oil carried into the system.
Please pay more attention to the oil temperature, which is crucial to compressor bearings’ life. Oil is with much lower
viscosity at high temperatures. Too low viscosity of oil will result in poor lubrication and heat dissipation in the
compressor. Viscosity is recommended to keep over 10mm
2
/s at any temperatures for oil. Oil temperature in the oil
sump should be kept above the saturated condensing temperature to prevent refrigerant migration into lubrication
system. Oil has a higher viscosity in low ambient temperature circumstances. When viscosity is too high, slow flow
speed of oil into the cylinder may result in too slow loading of the compressor. To solve this problem, use of oil heaters
can warm up oil before starting.
If the compressor operates under critical operating conditions, an extra oil cooler is required – please refer to Hanbell
selection software for the required capacity and oil flow of the extra oil cooler. Highviscosity oil is recommended to
apply in high operating conditions because high discharge temperature will make viscosity of oil lower. Oil return from
the evaporator may be insufficient in refrigeration systems, flooded chillersetc., in which it’s difficult for oil to be
carried back and it may cause oil loss in the compressor. If the system encounters the oil return problem then an extra
2
nd
oil separator is recommended to be installed between the compressor discharge tube and condenser.
Each of HANBELL RC2230 ~ RC2930 compressors is equipped with two oil sight glasses as a standard (the second
sight glass is optional for the models RC2100 ~ RC2200), one is the highlevel sight glass, and the other is the low
level sight glass (RC2230~RC2510, RC2580 and RC21020~RC21530) or internal oil line sight glass (RC2550 &
RC2620~RC2930). The function of internal oil line sight glass is to monitor lubricant flow to capacity control system
and bearings. While reverse running, it is unable to see the oil flow via sight glass. The normal oil level in the
compressor oil sump should be maintained above the top of the lowlevel sight glass and in the middle level of high
level sight glass when compressor is running. It is strongly recommended to install the oil level switch (optional
accessory) to prevent the failure results from lose of oil.
3.1 Lubricants table
Applicable oil types (R22)
SPECIFICATION UNITS HBR B10
HBR A02 HBR A04 HBR B09 HBR B02 HBR B01
COLOR, ASTM 1.5 L1.0 L1.0
−
−
−
SPECIFIC GRAVITY 0.883 0.914 0.925 0.95 1.01 1.05
VISCOSITY
40℃
mm
2
/s (cSt)
56.0 54.5 96.5 175 168 298
100℃ 7.0 6.07 8.12 16.5 20.2 32.0
FLASH POINT ℃ 220 188 198 265 290 271
POUR POINT ℃ 40 35 25 30 43 35
T.A.N MgKOH/g 0.01 0.00 0.01
−
−
−
COPPER STRIP 100 /3hr℃ 1a 1a 1a
−
−
−
MOISTURE ppm 15 20 20
−
−
−
FLOC POINT ℃ 75 45 35
−
−
−
DIELETRIC STRENGTH
(2.5mm)
KV 75 50 50 46.6
− −
Applicable oil types (R134a, R404A, R407C)
SPECIFICATION UNITS HBR B05 HBR B08 HBR B09 HBR B04
COLOR, ASTM
−
−
−
−
SPECIFIC GRAVITY 0.945 0.94 0.95 0.95
VISCOSITY
40℃
mm
2
/s (cSt)
64 131 175 215.9
100℃ 8.9 14.53 16.5 20.8
FLASH POINT ℃ 266 254 265 271
POUR POINT ℃ 43 36.5 30 25
T.A.N mg KOH/g
−
−
−
−
COPPER STRIP
100 /3hr℃
− − − −
MOISTURE ppm
−
−
−
−
FLOC POINT ℃
−
−
−
−
DIELETRIC STRENGTH
2.5mm
KV
− −
46.6
−
Note: For other applicable oil types (HFO Refrigerant), please consult HANBELL firstly for approval.