RXB PLUS ROTARY SCREW COMPRESSOR UNITS
OPERATION
070.101-IOM (JAN 13)
Page 30
RXB COMPRESSOR
The. Frick.
RXB
. rotary. screw. compressor. utilizes. mating,.
asymmetrical-profile.helical.rotors.to.provide.a.continuous.
pulse-free.flow.of.refriger.ant.vapor.and.is.designed.for.both.
high.pressure.and.low.pressure.applications..The.compres.sor.
incorporates.the.following.features:
1.
.High-capacity.roller.bearings.to.carry.radial.loads.at.both.
the.inlet.and.outlet.ends.of.the.compressor.
2.
. Heavy-duty,. four-point,. angular-contact. ball. bearings.
to. carry. axial. loads. are. mounted. at. the. discharge. end. of.
compressor.
3.
. Moveable. slide. valve. to. provide. infinite. step. capacity.
control.from.100.to.25%.of.full.load.
4.
.VOLUMIZER
®
.adjusts.to.the.most.efficient.of.three.volume.
ratios. (2.2,. 3.5. or. 5.0). depending. upon. system. require-
ments.
5.
. A. hydraulic. unloader. cylinder. to. operate. the. slide. stop.
and.slide.valve.
6.
. Compressor. housing. suitable. for. 350. PSI. pressure..
Dual-.compressor.casing.design.for.very.low.airborne.noise.
trans.mission.
7.
.Most.bearing.and.control.oil.vented.to.closed.thread.in.
the.compressor.instead.of.suction.port.to.avoid.performance.
penalties.from.superheating.suction.gas.
8.
.Shaft.seal.design.to.maintain.operating.pressure.on.seal.
well.below.discharge.pressure.for.increased.seal.life.
9.
.Oil.injected.into.the.rotors.to.maintain.good.volumetric.and.
adiabatic.efficiency.even.at.very.high.compression.ratios.
IT IS MANDATORY THAT THE COU-
PLING CENTER BE REMOVED
AND THE DIRECTION OF MOTOR
ROTATION BE CONFIRMED
BEFORE
RUNNING THE
COMPRESSOR. Proper rotation of the compressor shaft
is clockwise looking at the end of the compressor shaft.
FAILURE TO FOLLOW THIS STEP COULD RESULT IN
BACKWARD COMPRESSOR ROTATION WHICH CAN
CAUSE COMPRESSOR FAILURE OR EXPLOSION OF
THE SUCTION HOUSING.
COMPRESSOR LUBRICATION SYSTEM
The.
RXB
.compressor.is.designed.specifically.for.operation.
without. an. oil. pump. for. high. stage. service.. Boosters. and.
some.low-differential-pressure.appli.cations.will.require.the.
full-lube.pump.option.
The.lubrication.system.on.an.
RXB
.screw.compressor.unit.
performs.several.functions:
1.
.Lubricates.the.rotor.contact.area,.allowing.the.male.rotor.
to.drive.the.female.rotor.on.a.cushioning.film.of.oil.
2.
.Provides.lubrication.of.the.bear.ings.and.shaft.seal.
3.
.Serves.to.remove.the.heat.of.compression.from.the.gas,.
keeping.discharge.temperatures.low.and.minimizing.refriger-
ant.or.oil.break.down.
4.
.Fills.gas.leakage.paths.between.or.around.the.rotors.with.
oil,.thus.greatly.reducing.gas.leakage.and.main.tain.ing.good.
compressor.per.formance.even.at.high.compres.sion.ratios.
5.
.Provides.oil.pressure.for.development.of.balance.load.on.
the.balance.pistons.to.reduce.bearing.loading.and.increase.
bearing.life.
FULL-LUBE OIL SYSTEM
RXB PLUS
.booster.compressors.and.high-stage.compres-
sors,.that.operate.with.very.low.differential.pressures.across.
the.compressor.suction.and.compres.sor.discharge,.require.
a.full-time.oil.pump.to.produce.the.oil.flow.and.pressures.
required..Oil.is.pumped.from.the.oil.separator.through.the.
oil.filter.to.the.main.oil.injection.feed.and.the.compressor...
An.oil.pressure.regulating.valve.downstream.of.the.pump.is.
used.to.regulate.oil.pressure.at.the.compressor.by.returning.
excess.oil.to.the.separator.
Oil.pressure.on.
RXB PLUS
.compressors.with.full-time.oil.
pumps. should. be. adjusted. to. provide. 20. –. 25. PSI. (high.
stage).or.30.–.35.PSI.(booster).pounds.of.oil.pressure.at.
the.highest.normal.head.pressure.or.intermediate.pressure.
expected.with.the.compressor.fully.loaded..The.compressor.
will.require.maximum.oil.flow.under.these.conditions.
COMPRESSOR OIL SEPARATION SYSTEM
The.
RXB PLUS
.is.an.oil.flooded.screw.compressor...Most.
of.the.oil.discharged.by.the.compressor.separates.from.the.
gas.flow.in.the.oil.charge.reservoir..Some.oil,.however,.is.
discharged.as.a.mist,.which.does.not.separate.readily.from.
the. gas. flow. and. is. carried. past. the. oil-charge. reser.voir..
One.or.more.coalescer.filter.elements.then.coalesce.the.oil.
mist.into.droplets;.the.droplets.of.oil.fall.to.the.bottom.of.the.
coalescer.section.of.the.oil.separator..The.return.of.this.oil.
to.the.compressor.is.controlled.by.a.needle.valve.on.both.
high-stage.and.booster.applications.
NOTE: Open needle the valve only enough to keep the
coalescer end of the separator free of oil.
The. sight. glass. located. near. the. bottom. of. the. coales.cer.
section. of. the. oil. separator. should. remain. empty. during.
normal.operation..If.an.oil.level.develops.and.remains.in.the.
sight.glass,.a.problem.in.the.oil.return.separation.system.or.
compressor.operation.has.develop.ed..Refer.to.Maintenance.
for.information.on.how.to.correct.the.problem.
NOTE: Normal operating level is between the top sight
glass and bottom sight glass.