Sealing Characteristics of Stuffing-Box Seals for Rotating Shafts

Abstract

There are two distinct modes of operation of a stuffing-box seal. One mode occurs when the axial pressures produced in the packing by tightening the gland-bush are greater than the sealed fluid pressure and the other when they are less. Under the former conditions the fluid pressure distribution is an exponential function of the packed length and the frictional torque increases rapidly with this quantity. With high fluid pressures, however, the relation between fluid pressure and packed length is no longer exponential and most of the fluid pressure drop occurs over the last 10 per cent of the packed length. In addition very little increase in frictional torque occurs when the packed length is increased. Theoretical expressions have been derived for pressure distribution and friction torque and good agreement has been obtained between these and experimental results.