EMERGENCY SEALANT INJECTION ON TRUNNION MOUNTED BALL VALVES
November 8th, 2017 by Amanda Schumann
Be careful with trunnion mounted ball valves 100mm (4”) and under and in reduced bore 150mm (6”) and under as many manufacturers cannot put a sealant injection directly onto each seat such as in the photo shown above (RHS). They can only fit a sealant injection to the middle of the body (photo LHS). Consequently if you try and put sealant injection into the middle of the body and the valve is in the closed position all you’re doing is injecting grease into the middle of the ball. You have to have the valve in full open position then you have to keep squirting sealant injection until the entire cavity around the ball itself is full, then you have to open and close the valve to wipe the grease onto the seats. For this reason Australian Pipeline Valve and our other manufactures, as well as Sferova, are able to supply sealant injection direct to both seats even on 50mm (2”) avoiding this problem. Of course always remember the sealant injection facility is only for emergency sealant injection. Once you apply grease to the seat you have the added risk of debris sticking to the grease on the seat and then further damaging the valve seat once the valve is again opened and closed. Of course you can also flush the sealant injection lines clean afterwards. Read more on the Australian Pipeline Valve Installation, Operations & Maintenance manual click here where it explains utilising the sealant injection facility for commissioning/purging of seat area prior to turning the valve, etc. Most valves are also fitted with an stem emergency sealant injection.
All sealant injection fittings used by Global Supply Line’s manufacturer’s such as Australian Pipeline Valve, JC, Starline & Sferova have a double check valve and are 316 stainless steel.