070.250-IOM (APR 11)
Page 16
408 MM ROTARY SCREW COMPRESSOR
OPERATION
OPERATION
OPERATION AND START-UP INSTRUCTIONS
The Frick 408 mm Rotary Screw Compressor will be a
component in an integrated system. As such the compressor
requires some specific operation and conditions to ensure
trouble-free running.
The information in this section of the manual provides the
logical step-by-step instructions to properly start up and
operate the 408 mm Rotary Screw Compressor in your unit.
Only matters which may influence the proper operation of
the 408 mm compressor are included.
THE FOLLOWING SUBSECTIONS MUST BE READ AND
UNDERSTOOD BEFORE ATTEMPTING TO START OR
OPERATE THE UNIT.
COMPRESSOR HYDRAULIC SYSTEM
(The solenoid valves and manifold block are
available as a sales order option)
The compressor hydraulic system actuates the movable slide
valve (SV) to load and unload the compressor. It also actuates
the movable slide stop (SS) to increase or decrease the
compressor’s volume ratio (Vi). The hydraulic cylinder
located at the inlet end of the 408 mm compressor serves a
dual purpose. It is separated by a fixed bulkhead into two
sections. The SV section is to the left of the bulkhead and
the SS is to the right if you are facing the right side of the
compressor. Both operations are controlled by solenoid
valves, which are actuated when a signal from the appropriate
microprocessor output energizes the solenoid valve.
SINGLE-ACTING MODE - High Stage
Open valve at SC1
Close valve at SC2
Open valve at BP (bypass)
High stage compressor loading:
The compressor loads
when SV solenoid YY2 is energized and oil flows from the
unload side of the cylinder out port SC1, through valve ports
A and T to compressor suction. Simultaneously, discharge
pressure loads the slide valve.
High stage compressor unloading:
The compressor
unloads when SV solenoid YY1 is energized and oil flows
from the oil manifold through valve ports P and A to cylinder
port SC1 and enters the unload side of the cylinder.
Simultaneously, gas on the load side of the cylinder is
vented through port SC2 and valve BP to compressor
suction.
NOTICE
To control the rate of loading and unloading, throttle
the needle valve at SC1 port.
DOUBLE-ACTING MODE - Booster (low differential)
Open valve at SC1
Open valve at SC2
Close valve at BP (bypass)
Booster Compressor Loading:
The compressor loads when
SV solenoid YY2 is energized and oil flows from the oil
manifold through valve ports P and B to cylinder port SC2
and enters the load side of the cylinder. Simultaneously, oil
contained in the unload side of the cylinder flows out
cylinder port SC1 through valve ports A and T to compressor
suction.
Booster Compressor Unloading:
The compressor unloads
when SV solenoid YY1 is energized and oil flows from the
oil manifold through valve ports P and A to cylinder port
SC1 and enters the unload side of the cylinder. Simultaneously,
oil contained in the load side of the cylinder flows out of
compressor port SC2 through valve ports B and T to
compressor suction.
NOTICE
To control the rate of loading and unloading, throttle
valves SC1 and SC2.
NOTICE
To slow all valve movements - loading, unloading, and
Vi change - throttle valve 2.
Figure 10 - Solenoid Valve Block
CAUTION
NEVER open valve BP and valve SC2 at the same time
during compressor operation.
VOLUMIZER VOLUME RATIO CONTROL
Open valve at SC3
Open valve at SC4
Compressor Vi increase:
The volume ratio Vi is increased
when MSS solenoid valve YY3 is energized and oil flows
from the oil manifold through valve ports P and A to
compressor port SC3, enters the increase side of the
cylinder and overcomes the decrease spring tension.
Compressor Vi decrease:
The volume ratio Vi is decreased
when MSS solenoid valve YY4 is energized and oil flows
from SC3 through valve ports A and T to compressor port
SC4, to compressor suction.
TO CONTROL THE RATE OF Vi CHANGE, THROTTLE THE
NEEDLE VALVE AT SC3 PORT.
