TL;DR
Piston rod packing leakage is a process gas release and a safety issue. Measure vent flow, inspect the rod surface, and plan a packing replacement before the leak worsens.
What you might see
- process gas detected at packing case vent
- packing vent flow above normal
- rod wiper oil contaminated with process gas
- packing case temperature rising
Likely causes
Packing ring wear from extended operating hours
Rod surface wear or roughness from lubrication failure accelerating ring wear
Contaminated lube oil reducing packing lubrication film
Thermal or pressure cycling stressing the packing rings beyond design limits
Required tools
- Gas detector (calibrated for process gas type)
- IR thermometer
- Packing vent flow meter
- Oil sample kit
- LOTO kit
Safety first
- Reciprocating compressors handling hydrocarbon gas or H2S require H2S monitoring and supplied-air equipment when the packing vent exceeds safe limits. Wear supplied-air respirator in the area when vent flow is above normal.
- Ignition sources must be controlled around a hydrocarbon gas compressor with a known packing leak. Use a gas detector before entering the compressor building.
- Lock out and de-inventory the compressor before opening any packing case. Confirm gas-free before disassembly.
Procedure
- 1
Monitor the packing vent flow rate and trend it against the manufacturer's normal range. Rising vent flow is the primary diagnostic.[1]
- 2
Check the packing case temperature with an IR thermometer. Elevated temperature indicates friction from ring-to-rod contact.[1]
- 3
Inspect the packing lube oil supply flow rate and pressure at the packing injection point.
Warning: Process gas at the packing vent is a hazard. Confirm the gas type and concentration with a gas detector before approaching the vent line. Hydrocarbon gas is flammable; H2S is toxic. - 4
Take an oil sample from the packing lube oil circuit. Metal particles indicate advanced ring wear.
- 5
If vent flow is at or above the shutdown limit, plan an immediate compressor shutdown for packing replacement.
- 6
Inspect the rod surface for scratching, scuffing, or out-of-round condition during the planned outage. A damaged rod accelerates new packing wear.
- 7
Replace packing rings as a complete set per cylinder. Mixing old and new rings leads to uneven loading.
Sources
Ariel Corporation Ariel JGC / KBV / KBZ Reciprocating Gas Compressor general technical documentation, Ariel Corporation
Ariel JGC / KBV / KBZ reciprocating compressor general piston rod packing inspection and replacement procedures (general)
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