A circuit for generating an output voltage which is proportional to temperature with a required gradient is disclosed. In these CDACs, matching of capacitive values is important, and for conventional high resolution SAR ADCs, complex trimming or calibration procedures can be too costly. The system eliminates the need to suspend individual bricks from above the roof, and provides simultaneous support and cooling of the roof structure. Thus, the packing system of the present invention provides a simplified method to load and monitor a barrier in the stuffing box of the valve to slightly higher pressure than processed fluid pressure.