SEALANT INJECTION FACILITY ON TRUNNION MOUNTED BALL VALVES – A CONTENTIOUS ISSUE
May 2nd, 2018 by Amanda Schumann
The issue of the sealant injection facility on trunnion mounted ball valves with soft seat inserts is highly contentious. Over the years I’ve heard every argument ranging from people who say you should not even have a sealant injection facility permitted for fear of operators randomly pumping grease into a valve as they would a Plug valve or an API6D Gate valve which could then contaminate the product or also possibly attract grease or other debris which could further damage the seats. Technically debris should ‘wipe off’ but in practise this isn’t always the case with larger particulates. Many people believe the valves can be permanently greased rather than just having the sealant injection facility for emergency use and that this will prevent seat damage allowing particles to ‘slide off’ the seat surface.. The mainstream train of thought recommended by most manufactures is that they’re only for emergency however, with the added advantage they can also be used for pre-flushing during commissioning or flushing in the event of some sort of sticking or seat damage problem before sealant injection is inserted. Also see our post on single sealant nipples to body (100NB & under) and how they cannot be greased in the same way as seat sealant nipples, click here. The below is an extract from the Australian Pipeline Valve Installation, Operations & Maintenance manual for Trunnion Mounted Ball Valves. You can see the full procedure and instructions at our website by clicking on this link. The reason people’s comments will vary so differently is it depends on what size, class, service, pressure range, valve design, etc., you are talking about. Also practicality, serviceability, cost factor and criticality of a leak all come into play in making your decision. Either way, you will find the Australian Pipeline Valve range of IOM’s invaluable for all types of valves, irrespective of what brand of valve you have in the line as our IOM’s cover important points that need to be considered for all brands with a similar design in the commodity Oil & Gas valve arena.