Pressure balance packing is designed for elevator jacks and has these features. It is a non-adjustable floating type seal, allowing the cap bolts to be tightly in place. The internal ribs are molded diagonally to provide internal spring-action for positive sealing from zero pressure to 1500 psi.

A single seal is all that is required to provide oil retention. However, when gland clearance is too great, a backup ring is provided to prevent seal extrusion. Some packing boxes are provided with an oil return line arrangement that will require two seals and a spacer (or lantern ring).

Packing friction can affect the operation of the control valve and should be corrected before adjusting the valve. Both a rough upstart and/or a bumpy down-start are an indication of excessive friction. Gorman pressure-balance seals, including GCI wiper and correct installation procedures, will normally correct friction and/or leaking problems.