Adjustable stuffing boxes for pump rods

Abstract

Stuffing boxes for use with reciprocating or rotating pump rods for downhole pumps include a lower housing adapted to be mounted on a wellhead and provided with internal bores for receiving the pump rod and a packing housing engaged with the lower housing and including a central bore for receiving a packing assembly and a packing gland. The packing gland may include an annular flange for supporting circumferentially spaced bolts engageable with cooperating bores in the packing housing to adjust compression on the packing and to provide for rotatably indexing the gland to minimize uneven wear. An axially slidable bushing mounted in the packing housing or lower housing is engageable with the opposite end of the packing assembly and is provided with a transverse annular shoulder engaged by a bias spring for exerting compression forces on the packing assembly. The bushing includes a transverse end face exposed to pressure fluid to also urge the bushing into engagement with the packing assembly. An annular cavity for the bushing bias spring may be filled with a lubricant at neutral pressure provided by equal diameter portions of the bushing. An annular packoff element may be disposed in the lower housing and engaged by the packing housing to form a temporary seal during repair or replacement of the packing assembly and/or the packing gland.