Page 144 - Reciprocating Compressors Operation Maintenance

! 3O Reciprocating Compressors: Operation and Maintenance

should be operated by hand to provide an extra supply of oil. Condensa-
tion of moisture will occur during the shutdown period, and the extra
supply of oil will provide additional protection against rusting,
A practice often adopted where large compressors are used consists of
opening the cylinders and swabbing them with special oil to protect
against rusting during long shutdowns.
Before starting a compressor after an extended shutdown, the oil lines
to the cylinders should be disconnected at the cylinders, and lubricators
should be pumped by hand until oil flows at the disconnected end. The
lines should then be reconnected, and the lubricator should again be
operated by hand to provide an initial supply of oil to the cylinders. Fur-
thermore, about twice the normal rate of feed should be maintained for
the first hour of operation.
An alternative method often used to protect compressors during long
periods consists of running them unloaded for a few minutes each day or
blanketing them with an oil-mist environment.
Conventional, long-term storage protection would include at least the
following 13 steps:

1. Remove all cylinder valves, unloaders, and rod packing. Coat and
store in warehouse.
2. Blind opening at rod packing box.
3. Blind compressor gas inlet and discharge casing connections, after
filling cylinder and gas passages completely with an approved
preservative oil. (Allow some space for thermal expansion.)
4. Do not clean or coat cylinder cooling passage. Flush only with
water, drain and air dry. Plug inlet cooling passage. Leave low-
point drain cracked open and wire valve in this position (this per-
mits self-draining of any atmospheric condensation).
5. Blind opening at wiper ring adjacent to crosshead compartment.
6. Fill crankcase and crosshead compartment completely with a suit-
able preservative oil. Install a valved vent (at high point, if possi-
ble) to permit addition of rust preventative later if required.
7. Blank off pulsation bottles and knock out drums after coating with
an approved preservative (fill and then drain vessels).
8. Coat intercooler/aftercooler gas passages (not water passages) with
suitable, approved preservative by filling and draining. Blank or