Paper Mill North America
A 20” process treatment valve had developed a severe leak when operators attempted to close the valve. Several bonnet bolts had snapped under load of operation and large sections of gasket were dislodged from internal pipeline pressure. The pipeline was operating at 120psi and 100f. Isolating this valve from upstream would require a total plant shutdown.
RJ Stacey and plant safety first determined that the valve could be approached only with specific safety procedures in place. Next, the RJ Stacey team with the use of hydraulic actuators and cables firmly restrained the bonnet to the valve to prevent any further failure of the valve during our repairs. Then, we replaced all the bonnet bolts one at a time permanently securing valve integrity. At this point, the valve bonnet was peened and injected with an appropriate sealant.
The resulting leak repair was a complete success. The pipeline remained live and in service throughout the repair process. Additionally, the bonnet was now firmly attached to the valve body. We were able to exercise the valve which had been neglected for decades and hold it closed so that plant maintenance could proceed with their downstream project.