Performance of a Modified Packed-Gland Seal

An experimental investigation of the mechanics of hydrodynamic lubrication and heat generation and dissipation of packed-gland rotary shaft seals was performed on a somewhat novel design. The design differs from conventional stuffing-box seals in that the packing was inverted so that it rotated with the shaft. It was also skewed so as to enhance heat transfer and lubrication. Further, the gland was loaded hydraulically so that the axial pressure applied to the packing was readily controllable. These modifications proved to be successful in that much improved stability of operation was obtained through lowered coefficients of friction (with water as the sealed fluid) and interface temperature which prolonged seal life without serious detriment to leakage. Some rheological data on Teflon-asbestos packing is presented as well as kinetic coefficients of friction. Motion picture frame photographic sequences of the packing interface showing packing deterioration and lubricant film cavitation are included also.