A control valve includes a valve body, a valve stem, and a control element. The valve body receives the stem and includes a packing box housing a packing set. A packing follower includes a bore sized to receive the stem and includes an upper portion, a lower portion, and a bearing surface, the lower portion sized to extend into the valve bonnet to engage the packing set to apply a first compressive force to the packing set, the upper portion including threads and having an upper counterbore housing a secondary seal ring. A nut operatively engages the threads of the upper portion of the packing follower, the nut positioned to apply a second compressive force to the secondary seal ring, and a spring is positioned between the packing flange and the bearing surface of the packing follower, wherein the first compressive force is independent of the second compressive force.