Live-Loaded Packing With Load Scale – For extremely high temperature and high pressure applications, a graphite packing arrangement that does not include PTFE packing washers may be specified. The graphite packing arrangement that is illustrated in Figure 30 is rated to 1 200 degrees F. However, the stem friction is extremely high and packing loads must be carefully managed to prevent stem seizure. An adjustable Belleville spring arrangement allows precise adjustment of the packing loading.
As the Belleville springs are compressed (by tightening the packing flange nuts), the load scale moves down relative to the position of a fixed indicator disk. The position of the indicator disk relative to the load scale provides a visual indication of the amount of loading force that is applied to the packing by the packing follower.