An anti-static device is a set of spring-loaded conductive plungers that maintain electrical continuity between a ball valve's ball, stem and body, so static charge generated by the flowing medium drains safely to the grounded pipeline instead of accumulating and sparking. Standards typically require less than 10 ohms resistance.
The problem it solves is invisible: in a soft-seated ball valve the ball floats on PTFE — an excellent electrical insulator — and dry gas, steam or low-conductivity hydrocarbons rubbing past the ball generate static charge with nowhere to go. A charged, isolated ball can discharge as a spark inside a valve full of flammable vapour, precisely where ignition is least survivable.
The cure is mechanical and cheap: one small spring-loaded plunger between ball and stem, and another between stem and body, guarantee a continuous conductive path regardless of valve position or seat wear. Design standards — ISO 17292, API 608, API 6D and BS 5351 heritage specifications — require the antistatic feature for soft-seated valves in flammable service and verify it as a resistance measurement (typically ≤10 Ω across ball-to-body) on the finished valve.
On datasheets the feature appears as "anti-static device to ISO 17292" and should be paired with fire-safe certification for hydrocarbon duty. VTXFLOW fits anti-static plungers as standard on all soft- and metal-seated ball valves; continuity is checked at final inspection alongside the API 598 pressure tests.