Long Term Behaviour of Stuffing Box Packings Under the Influence of Fluids at High Temperature

Testing techniques were developed to investigate the long-term behaviour of stuffing box packings under real service conditions. This equipment meets all requirements for the simulation of high temperature applications with gaseous fluids, hot water and steam: • controlled pre-tightening (gland load); • variation of the stiffness of the assembly (e.g. Bellville springs); • determination and monitoring of packing stress - respective gland load; • control of stroke and stem force; • heating-up, pressurization and temperature control; • conditioning of water and steam chemistry. All relevant influencing parameters on the long-term behaviour of varied stuffing box packings based on flexible Graphite, woven PTFE fibres and special packing designs were taken into consideration: • assembly procedure (packing stress); • stroke and number of cycles; • effect of Bellville springs; • medium and temperature. In detail, friction, relaxation and leakage tests were carried out. On the basis of these results an evaluation of the long-term performance of the different packing types based on Graphite and PTFE is possible.