Page 270 - Reciprocating Compressors Operation Maintenance

Overhaul and Repair of Reciprocating Compressors 255

* Ensure housing, crankshaft, and oilways are thoroughly cleaned.
* Ensure any locating dowels are satisfactory and free from burrs. The
locating tab should be correctly positioned.
* Ensure the bearing has a positive free spread.
* Clearly mark on the bearing its location within the compressor.
* Clearly mark on one end of each bearing housing its position within
the compressor.
* Do not apply oil between bearing back and housing bore.
* Apply a liberal coating of oil between bearing bore and crankshaft
surfaces.
* Tighten bolts in the correct sequence to the correct torque or stretch,
as defined in the equipment instruction manual.
* Check that the shaft can rotate freely.
REMANUFACTURING OF SHELL-TYPE BEARINGS

Remanufacturing or rebabbitting of shell-type compressor bearings
should be done only to specific styles.
The old bearing shells with thick babbitt, usually .032" to .064", can
be rebabbitted by a shop experienced in this type of work. Centrifugal
casting or spraying of the babbitt has been found superior to pouring bab-
bitt in these shells.
The newer shells with reduced babbitt thickness (.007"-.015"), can be
rebabbitted by centrifugal casting if the backing is made of cast iron or
steel. Bearings made with bronze backing should never be rebabbitted
because the bearing shell crush has been destroyed.
Shells made of the tri-metal construction should not be remanufac-
tured or rebabbitted.
Any bearing shell that is rebabbitted should be checked by ultrasonics
to be sure the area between the babbitt and the backing is 100% bonded.

COMPRESSOR COMPONENT REPAIR AND REBUILDING

In the overhaul and maintenance of the reciprocating compressor,
many repairs can and are made to the major components. When making
repairs, several things must be considered to prevent jeopardizing the
integrity of the part and to ensure that it performs as good or better than
the original installed in the compressor by the manufacturer. Here are
questions to ask: