Patent ID: 8631861

Claim:
For a well producing well fluids, and in combination with a reciprocating plunger type pump having a polished rod, a packing unit, through which the polished rod moves, the packing unit comprising: a housing having a chamber and a downward facing shoulder; a packing assembly, positioned within the housing chamber, through which the polished rod moves, the packing assembly having: a packing assembly center portion, the center portion being sealed against the housing to divide the housing chamber into an upper chamber and a lower chamber, the well fluids being received in the housing lower chamber, the well fluids pressurably engaging the packing assembly center portion; a bottom portion, the bottom portion supporting the center portion within the housing, the housing upper chamber containing a barrier fluid, the barrier fluid pressurably engaging the packing assembly center portion; and a top portion, the top portion comprising: a load ring, through which the polished rod travels; a seal positioner, through which the polished rod travels, the seal positioner supporting the load ring, the load ring being laterally movable with respect to the seal positioner, the seal positioner positioning at least one packing seal element about the polished rod, the seal positioner having a bottom, the seal positioner bottom being pressurably engaged by the barrier fluid, the pressured engagement displacing the seal positioner such that the load ring is moved against the housing downward facing shoulder, the load ring bearing upon the shoulder to divide the housing upper chamber into an upper chamber first sub-chamber and an upper chamber second sub-chamber, the seal positioner being positioned in the upper chamber first sub-chamber, the second sub-chamber being separated from barrier fluid pressure; and at least one packing seal in the housing upper chamber second sub-chamber; the packing unit further comprising a pressure transmitter having a cylinder and a piston within the cylinder, the cylinder having a well fluid communication end, the well fluid communication end fluidically communicating with the housing lower chamber such that well fluid pressures the piston, the cylinder having a barrier fluid communication end, the barrier fluid communication end fluidically communicating with the housing upper chamber, such that the barrier fluid pressurably engages the piston; the piston being sized such that the pressure from the well fluid on the piston is transmitted to the barrier fluid, the barrier fluid being pressured in the housing upper chamber to oppose the well fluid pressure on the packing assembly center portion and to pressurably displace the seal positioner.