Patent ID: 6953182

Claim:
A control valve comprising: a valve body defining a top opening; a bonnet adapted to close the top opening of the valve body, the bonnet including a lower surface and defining a central bore wherein the lower surface of the bonnet includes an inwardly chamfered recess; a stem sized for insertion through the bonnet central bore and slidable in the central bore; a plug coupled to the stem and adapted to move in the valve body between an open position and a closed position; a packing assembly disposed between a portion of the bonnet central bore and the stem for sealing between the stem and the bonnet; a packing retainer attached to a bottom end of the bonnet, and adapted to retain the packing assembly within the bonnet central bore and around the stem; and a retainer ring including an upper portion having a chamfered projection, the retainer ring being adjustably coupled to the packing retainer wherein tightening the retainer ring on the packing retainer provides mating of the chamfered projection of the retainer ring and the chamfered recess of the bonnet, thereby centering the packing retainer with in the bonnet central bore and engaging the bonnet lower surface to secure the packing retainer in place.