Page 231 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Reciprocating Gas Engines and Compressors 213

A typical detailed break-in procedure. for tungsten carbide coated rods
is described in the following:

0 Machine made ready to operate by process personnel.
0 Set load at 25 percent and run machine forfive minutes.
0 Shut machine down and allow piston rod to cool down to ambient
temperature.
Set load at 25 percent and run machine for 20 minutes.
Shut machine down and allow piston rod to cool down to ambient
temperature.
Set load at 50 percent or less and run machine for one hour.
Shut machine down and allow piston rod to cool down to ambient
temperature.
Run-in is now completed.
Put machine on line and set for desired operation.

The purpose of this run-in procedure is to allow the TFE packing to
warm up gradually and “flow” to the contour of the piston rod. The the-
ory is that putting the machine on line, as one might have done in the
past, just “melts” and burns the packing so it can never seal.

Removal of piston rod packing consists of these steps:

1. Remove crosshead guide side covers.
2. Position compressor piston at extreme crank end of its stroke. If the
packing case does not require removal, it is not necessary to discon-
nect the piston rod from crosshead.
3. Remove crosshead diaphragm packing
4. Remove crosshead diaphragm-Figure 5- 16-and move diaphragm
toward crosshead as far as possible.
5. Disconnect piping from the packing case flange.
6. Remove nuts from flange studs and slide case from pocket in cylin-
der head.
7. Remove nuts that hold flange and packing cups together and slide
flange toward crosshead.
8. Separate packing cups, then remove garter springs and packing ring
segments.

Packing Cleaning and Inspection. Clean all metal parts in a suitable sol-
vent and dry thoroughly with a lint-free cloth. Inspect all parts for
cracks, breaks, scoring and wear. Inspect for weakened garter springs.
Do not break the corners where any two surfaces of a packing ring set
match. Do not file TFE packing.