070.610-IOM (JUL 21)
Page 23
RWF II Rotary Screw Compressor Units
Operation
Operation
11.
Shaft rotation clockwise facing compressor, suitable for
all types of drives.
See the following warning
.
WARNING
Compressor rotation is clockwise when facing the
compressor drive shaft. See
The compres-
sor should never be operated in reverse rotation as
bearing damage will result.
Figure 25: Shaft rotation direction
12.
Dual compressor casing design for very low airborne
noise transmission.
13.
Suction flange is 300 psig ANSI type.
14.
Integral
suction strainer is provided on models 100 –
480 and 546. Models 496, 676, 856, and 1080 have
external
strainer.
15.
"D" Flange adapter for bolting directly to motor.
Compressor lubrication system
The lubrication system on an RWF II screw com pres sor
unit performs several functions:
1.
Provides lubrication to bearings and seal.
2.
Provides a cushion between the rotors to minimize
noise and vibrations.
3.
Helps keep the compressor cool and prevents
overheat ing.
4.
Provides an oil supply to hydraulically actuate the slide
valve and slide stop.
5.
Provides oil pressure to the balance pistons to help
increase bearing life.
6.
Provides an oil seal between the rotors to prevent ro-
tor contact or
gas bypassing.
The compressor unit may be equipped with either a no
pump or a demand pump lubrication system. Addition-
ally, either system may contain
dual oil filters and
liquid
injection,
water-cooled, or thermosyphon oil cooler for
compressor oil cooling.
No pump oil system
The RWF II screw compressor unit is designed to be
self-lubricating. Oil being supplied to the compres sor from
the oil separator is at system head pressure. Within the
compressor, oil porting to all parts of the compressor is
vented back to a point in the compres sor’s body that is at
a pressure lower than compressor
discharge pressure. The
compressor’s normal operation makes the compressor unit
operate essentially as its own
oil pump. All oil entering the
Operation and startup instructions
The Frick RWF II Rotary Screw Compressor Unit is an inte-
grated system consisting of seven major subsystems:
1. Quantum
™
HD Control Panel
(See publications 090.040-O, -M, and -CS)
2. Compressor
3. Compressor Lubrication System
4. Compressor Oil Separation System
5. Compressor Hydraulic System
6. Compressor Oil Cooling System
7. Compressor Easy-Start System
The information in this section of the manual provides the
logical step-by-step instructions to properly start up and
operate the RWF II Rotary Screw Compressor Unit.
NOTICE
The following subsections must be read and under-
stood before attempting to start or operate the unit.
SGC compressor
The Frick RWF II rotary screw compressor utilizes mating
asymmetrical profile
helical rotors to provide a continuous
flow of refriger ant vapor and is designed for both high-
pressure and low-pressure applica tions. The compressor
incorpor ates the following features:
1.
High-capacity roller bearings to carry radial loads at
both the inlet and outlet ends of the compres sor.
2.
Heavy-duty, four-point
angular-contact ball bearings
to carry
axial loads are mounted at the discharge end of
compressor.
3.
Balance pistons located in the inlet end of the
compres sor to reduce axial loads on the axial load bear-
ings and increase bearing life.
4.
Movable slide valve to provide fully modulating capac
-
ity control from 100% to approximately 10% of full load
capacity.
5.
Volume ratio control to allow infinite ly variable volume
ratio from 2.2 to 5.0 during compres sor operation for all
models.
6.
A hydraulic unloader cylinder to operate the slide stop
and slide valve.
7.
Bearing and casing design for 400 PSI discharge pres
-
sure. This psi rating applies only to the compressor and
does not reflect the design pressure of the various system
components.
8.
All bearing and control oil vented to closed thread in
the compressor instead of suction port to avoid perfor-
mance penalties from
superheating suction gas.
9.
Shaft seal design to maintain operating pressure on
seal well below discharge pressure, for increased seal life.
10.
Oil injected into the rotors to maintain good volumetric
and adiabatic efficiency even at very high compression
ratios.