A jammed 18 inch plug valve freed in one day on a live diesel line

The valve and its duty

The valve was an 18 inch lubricated plug valve on a live diesel tap-off. It would not open fully, and the operator had seen dripping from the top.

The drip meant a leak problem on top of the operating problem. A jammed valve on a live line blocks both operation and confident isolation.

Diesel service lets debris and old sealant harden inside the plug over time. The alternative fix, valve removal, would have needed a line shutdown and lifting.

What had been tried before

The valve held hardened sealant left from an older generation of servicing. That old sealant had set hard inside the valve over time.

Cleaning later displaced this old sealant together with the accumulated debris. Finding it confirmed why the plug had stopped moving freely.

The intervention

Our technician mobilised for a one-day intervention with a high-pressure gun. The gun pushes cleaner through the valve's own injection points under controlled pressure.

1. High-potency cleaner was injected to displace the hardened debris and old sealant.
2. A soak of three to four hours let the cleaner work through the compacted material.
3. Operation tests followed, moving the valve carefully within its approved limits.
4. The handover set a follow-up regime of periodic cycling and lubricant top-up.

The job record noted about 100 g of cleaner per inch of valve size. For this 18 inch valve, that came to roughly 2 kg. That was the reported practice on this job, not a rule for others.

All of the work ran online, with the diesel line still in service. The seized plug valve guide explains why plug valves jam and what helps.

What our products did

High-potency cleaner is the escalation grade for compacted debris and aged sealant. It softens the material so the plug can move without excessive operator force.

The soak stage gives the chemistry time that added force cannot replace. Forcing a jammed valve risks stem, gear and seat damage, so chemistry goes first.

Cleaning also exposes the true condition of the valve for the next decision. Only after cleaning can sealant or lubricant do useful work in a plug valve.

Explore valve products for the cleaner and sealant grades behind this work.

The outcome and the record

Our post-job report recorded the valve operating again after the cleaning round. It also recorded five valves in total responding well to service. The operator signed the service report, making the visit its own record.

Three weeks later, it ordered the next round of valve repair. That order included sealant for the same 18 inch valve.

See the field results from the full directory of live valve cases.