Dismantling, Inspection And Re-Assembly Of Suction And Discharge Valves; Compressor Purging; Troubleshooting Table Grasso Reciprocating Compressors - GEA Grasso VHS Series Installation And Maintenance Instructions Manual

DISMANTLING, INSPECTION AND RE-ASSEMBLY OF SUCTION AND DISCHARGE VALVES

2.8 DISMANTLING, INSPECTION AND RE-ASSEMBLY OF SUCTION AND DISCHARGE
VALVES
The suction and discharge valves of a refrigeration compressor are parts that are
heavily loaded both mechanically and thermally. Wear and life time of the valves
strongly depend on the working conditions of the compressor. It is recommended
that valve condition is regularly checked.For dismantling, inspection and re-
assembly of the valves, refer to the relevant paragraph of the Compressor
Service Instruction Manual.
2.9

COMPRESSOR PURGING

Procedure to purge the compressor (after maintenance jobs):
STATUS:
Stop valves of suction, discharge and oil return line are still closed (refer to
Section 2.5, Page 34) and compressor is filled with oil (refer to Section 2.6,
Page 36).
i.
ii.
iii.
iv.
v.
vi.
vii.
2.10

TROUBLESHOOTING TABLE GRASSO RECIPROCATING COMPRESSORS

P-NL-094_imm_VHS_English_13
26.07.2021
Hint!
A high working temperature and rapid temperature variations shorten
the life time of the valves, which, for this reason, require regular
inspection.
Hint!
In order to reduce the downtime involved in the valve inspection, it is
recommended to have as many complete valve assemblies in stock as
there are cylinders on the compressor.These valves can be exchanged
with the original valves; in this case, these original valves can be
inspected and repaired or replaced if necessary later.
Connect a vacuum pump to the evacuation/purging valve(s) and evacuate as
prescribed by local regulations. For the location of these valves refer to the
"Product Information".
When evacuation is completed open the discharge stop valve.
Watch suction and discharge pressure.
Hint!
If suction pressure increases quickly, the discharge valve assy is
leaking.
Start compressor.
Slowly open suction stop valve.
Open the stop valve in the oil return line of the oil separator (if present).
If a Self-Limiting Automatic Purger is not installed, purge the refrigerating
system (refer to the plant manual).
INSPECTION AND TROUBLE SHOOTING
37