... grease through the device. Each seat of the ball valve can separately cut off the medium at both ... the valve to realize double-block functions.Hot tags: Trunnion Ball Valve, China, mill, manufacturer, supplier, factory, wholesale, ... seatConnection: Flanged, welded endsDrive device: handle worm, motor-drive, pneumatic driveUrgent grease injection deviceOptional locking device or stem extentionDouble ...