8 Types of Drill Pipe Float Valves: Lake's Drill Pipe Float Valves Drill pipe float valves, or non-return valves, 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. Finding the best fit for every individual project is important, and the different types go beyond just the split between the F-type plunger valves and the G-type flapper valves. Hereâ??s a fast primer and reminder on the differences between the types of non-return valves available. 1. Model F Plunger Type Valve: 2. Model FA Ported Plunger Type Valve: 3. Model FC Plunger Type Automatic Fill Valve: 4. Model G Full Flow Flapper Type Valve: 5. Model GA Flapper Type Valve: 6. Model GC Automatic Fill Flapper Type Valve: 7. Model GCA Automatic Fill/Pressure Monitoring Flapper Type Valve: 8. Flapper Valve F/Dual Flapper Check Valve: