US Patent 9683430 Gas-lift plunger

A plunger for use in a downhole well includes a body having a bore formed axially-therethrough. An inner surface of the body that defines the bore forms a seat. A stop extends at least partially laterally through the bore. An obstructing member is positioned within the bore and configured to move axially within the bore between the seat and the stop. The obstructing member is configured to prevent fluid flow through the bore in one axial direction when in contact with seat, and to allow fluid flow through the bore in an opposite axial direction when in contact with the obstructing member as the plunger descends in the well.