US Patent 11414956 Injection valve and method

An injection valve including a primary valve having a flapper, a flapper seat configured to seat the flapper, and a flow tube disposed to move relative to the flapper and thereby cause the flapper to be unseated from the flapper seat, a secondary valve disposed within the flow tube, the secondary valve including a secondary housing, and an openable and closable flow port through the secondary housing, and an annular pressure-drop ring disposed between the secondary housing and the flow tube.