RIX Industries 2V3B-4.1V-P1A, Operating Instructions Manual

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RIX Industries MAN ‐ 2V3B ‐ 4.1V ‐ P1 Page 11
should establish reference data for use in scheduled maintenance by taking gauge readings when the
compressor is running under normal operating conditions.
The perimeter of valve seats and o-rings may be lightly lubed with appropriate grease to ease
assembly. Alignment pins may also be lubed to help hold in place. (see additional information in
chapter 7)
5.10 PISTON RINGS
As the piston rings wear, their ability to seal is diminished. Excessive wear will result in lower
compressor capacity, more frequent compressor operation and unnecessary wear on other
components. There is also risk of damaging cylinder liner walls if the rings wear out completely.
Excess piston to cylinder clearance, caused from either piston or cylinder liner wear, will significantly
decrease ring life. Cylinder bores should be observed for wear at ring change-outs and measured for
wear if ring life has significantly decreased. For maximum ring life, pistons should not be removed
from cylinders prior to ring replacement.
For the 3rd stage floating piston it is recommended that the piston be replaced with the rings as an
assembly at the first change-out, and thereafter as necessary. If undamaged, the original piston can
be re-ringed by the user and kept for the next change-out.
A common indicator of worn rings is low compressor flow. On this 2V3 unit, the 3rd stage is located
over the 2nd stage, and all 3rd stage piston ring blowby passes into the 2nd stage compression area.
As the 3rd stage rings wear, the 2nd stage pressure will tend to increase. Too much ring blowby will
cause the 2nd stage relief valve to pop, at which point the 3rd stage rings must be replaced. If the
2nd stage rings are also worn excessively, their leak rate may prevent the 2nd stage pressure from
increasing. Gas leaking past either the 1st or 2nd stage rings passes thru the distance piece to
atmosphere.
As the 1st or 2nd stages rings wear the cylinder pressures will tend to be lowered. With extreme
wear the compressor will not be able to compress to the design final stage discharge pressure.
Ring life will vary with discharge pressure, atmospheric temperature and frequency of start/stop
cycles. A low ambient temperature will increase ring life. Frequent start/stop cycles will reduce ring
life. If possible, allow downstream pressure to drop as low as possible before restarting compressor.
5.11 CYLINDER LINERS
When ring life deteriorates from normal, liners should be checked for surface finish, scoring or
excessive wear. Maximum wear will normally occur 1/3 to 1/2 way down the bore. A bore gauge is
the best way to measure wear. Check diameter at several depths for wash-boarding, and hone or
replace as required. See chapter 7 for maximum diameters. Cleaning may not be required on normal
ring change-outs unless contaminates are present.
The desired cylinder surface is a 16-32 crosshatch. Surface roughness is needed to allow engraining
of Teflon in the bore. A smoother bore will reduce ring life. Re-hone cylinder as required, removing
a minimum of material.