Frick SGXH-4021 - Volumizer Volume Ratio Control

070.650-IOM (JUL 19)
Page 34
SGC/SGX ROTARY SCREW COMPRESSOR
INSTALLATION
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owsfrom
the oil manifold through valve ports P and A to compressor port
SC3, enters the increase side of the cylinder and overcomes
thedecreasedspringtension.Simultaneously,oilowsfrom
SC4 port through valve ports B and T to compressor suction.
Compressor Vi decrease: The volume ratio Vi is decreased
whenMSSsolenoidvalveYY4isenergizedandoilowsfrom
the oil manifold through valve ports P and B to compressor
port SC4, enters the decrease side of the cylinder. Simultane-
ously,oilowsformSC3portthroughvalveportsAandTto
compressor suction.
To control the rate of vi change, throttle the needle valve at
SC3 port.