Flap Check Valve (FCV)

The flap check valve is designed for forward circulation of fluid through coiled tubing and to prevent backflow of wellbore fluids into the coiled tubing string. It is used during well workover and major repair operations performed with coiled tubing units. Design features and operating principle: The valve consists of a body with an axial through bore, into which replaceable valve cartridges are installed. These cartridges are equipped with sealing rings and spring-loaded flaps. The upper end of the valve body is fitted with a sub featuring a box thread, while the lower end is fitted with a sub featuring a pin thread. The body incorporates gripping grooves for engagement with a horn-type wrench. Seal integrity of the threaded connections is ensured by rubber seals supplied as part of the delivery package. The valve is run in hole on coiled tubing assembled with another downhole tools. During the operational procedure, if back pressure develops, the valve prevents reverse flow of wellbore fluid into the coiled tubing by means of spring-loaded flaps. To open the valve, the applied back pressure must exceed the pressure acting below the valve.