Drill Pipe Float Valve Oil workover rig Drillout cement plug with 6" tri cone bit BHA. are downhole safety valves that create barriers to prevent unwanted flow of fluids up the drill string. The valve locks down the flow of fluids while the crew at the rigfloor is making or breaking connections. Observed the drill pipe float valve, which also recognized as a non-return valve, is a specialized valve installed in the bottom hole assembly (BHA) and its primary function is to serve as a check valve,