Frick SGC 2824 User Manual

070.650-IOM (AUG 2015)
Page 18
SGC ROTARY SCREW COMPRESSOR
INSTALLATION
In most cases, SGCH/SGXH 355 and 408 compressor models
require an active regulation of the oil pressure to SB-2. Bal-
ance Piston Regulation (BPR) is needed because the gas
force varies with the position of the slide valve. A low slide
valve position could reduce the load below the minimum
required for the axial bearings. Figure 16 shows a piping and
instrumentation diagram of a compressor with BPR. There
areseveralBPRcongurationsavailableanditisimportant
to select one that works well for the application.
SB3
Each line connects to the main header
1.5”
1” Min.
SM1
SB2
SB4
P
OIL
BPR
Figure 16. SGXH Compressor (355/408) with BPR
Figure17showsastandardcongurationforthe355com-
pressor.ThiscongurationlowersoilpressuretoSB-2tobe
55 psi below discharge pressure when SV < 65%. Contact
thefactoryformorespeciccongurationinformation.In
the case that application and/or operating conditions
change,theBPRsettingsneedreviewedandconguration
changes should be expected. In that case, contact engi-
neering.UsetheCompressorOperatingLogSheettollin
your nominal operating conditions.
Oil Feed
From Header
Restriction
Orifice
Solenoid
Valve
Pressure
Regulating
Valve
To Compressor
Discharge Line
To Inlet Bearing Oil
SB-2 Port
P
S
S
Figure 17. Example BPR Conguration
Note: On all SGX compressors except the 408 models, the
oil feed also lubricates the inlet bearings. For the 408 com-
pressor (MK 2 version) the bearings are lubricated from the
SB-4 connection — for low differential applications the SB-2
port will not need to be piped.
CAUTION
Operating with incorrect balance piston pressure
settings and selection signicantly increases the risk of
compressor breakdown and reduced compressor life.
CAUTION
Changes to application and operating conditions may
change oil pressure requirements to the SB-2 port and
Balance Piston Regulator conguration settings.
Compressors with Squeeze Film Damper (SFD) in the
blocking diameters.
Compressor models with an “X” as the third character have
Squeeze Film Dampers (SFD) built into the rotor blocking
diameters (Fig. 15). The SFDs provide dampening of the
rotor’s movement reducing impacts and lowering the total
vibration of the compressor. In order for the SFDs to work
properly they need to receive “solid” oil — oil free of bubbles
and foam.
Solid oil can be attained by either:
pumping the oil pressure to a minimum of 36 psi above
discharge, or
cooling the oil. With enough sub-cooling, bubbles are
prevented from forming inside the SFDs.*
Compressor ports SB-3 and SB-4 supply oil to the SFDs. As
theoilowcanbesignicant,thefeedlinesmusthavea
well dimensioned size to keep the pressure drop low. Each
line should be connected directly to the main oil header
(Fig. 17). Some applications with low power consumption
and a smaller motor may not have additional pressure and/
or temperature requirements.
Frick Coolware can calculate oil ows, pressure and
temperature required. All nominal operation conditions,
including SB-3 and SB-4 oil pressure requirements, should
be added to your operation log. In the case of application
and/oroperatingconditionchanges,oilowsandsettings
willneed to bereviewed. Expect conguration orsetting
changes. Fill in the nominal operating conditions in your
Compressor Operating Log Sheet, and revise as needed
when the situation changes.
CAUTION
Operating with incorrect oil pressure to the SB-3 and
SB-4 ports will cause risk of high compressor vibration,
reduced compressor life and breakdown.
CAUTION
Changes to application and operating conditions may
change oil pressure and temperature requirements to
the SB-3 and SB-4 ports.
OIL COOLING REQUIREMENTS
Compressor oil needs to be cooled to control the discharge
temperature, maintain proper oil viscosity and to preserve
the life of the oil. Discharge temperature will be in the 170°
- 180°F range (see CoolWare
™
) for normal refrigeration ap-
plications.
One application that typically requires higher discharge
temperatures (as high as 280°F) is natural gas gathering at
the wellhead. Moisture is normally present in the gas and

Frick SGC 2824 Specifications

General

Brand	Frick
Model	SGC 2824
Category	Air Compressor
Language	English