1. US6283217 - Axial equalizing valve

A subsurface valve with a pressure equalizing mechanism is provided to permit pressure above and below a valve closure member to equalize prior to the opening of the valve closure member. An actuating key is releasably engageable with a recess in a flow tube that is moveably disposed within a longitudinal bore of the safety valve. An equalizing plug is disposed for reciprocal movement within a plug bore, and is moveable in response to movement of the actuating key. To open the valve closure member, the flow tube moves downwardly into engagement with the actuating key, thereby carrying the actuating key into engagement with the equalizing plug to shift the equalizing plug to an open or equalizing position. Pressure above and below the valve closure member is equalized through the equalizing plug prior to the opening of the valve closure member by further downward movement of the flow tube.