US Patent 10294755 Dual barrier injection valve with a variable orifice

A wireline retrievable injection valve for an oil or gas well has an internal valve that is initially moved to open a flapper safety valve and also opens to allow fluid flow through the valve. The internal valve includes a sleeve that opens the flapper safety valve and shields the flapper safety valve from fluid. In this manner the flapper valve is protected from being caused to “flutter” or “chatter” due to pressure variations in the fluid flow, which may damage the seat.