Reciprocating rod pump seal assembly

DETAILED DESCRIPTION These and other objects are attained in accordance with the concepts of the present invention through the provision of a combination stuffing box and pressure transmitter assembly where the box includes a housing having a bore.
A plunger or rod reciprocates with respect to the bore to perform a pumping function.
The stuffing box includes axially spaced primary and secondary seal means which engage outer surfaces of the rod to inhibit fluid leakage, and the seal means are separated by an annular chamber that is filled with a clean lubricating oil so that the opposed sides of the seal means are exposed to the pressure of lubricating oil.
The inner side of the secondary seal means is subjected to the pressures of the fluid being pumped.
However, such pressures also are transmitted by the transmitted assembly to the lubricating oil in the chamber by means such as a floating piston, or its equivalent, so that the pressures of the lubricating oil is substantially balanced with respect to the pressures of the pumped fluid.
Thus there is no substantial pressure differential which appears across the secondary seal means and which would otherwise tend to cause the pumped fluids to leak past it.
The primary seal means operates under optimum conditions to prevent leakage to the outside since it has a clean lubricating oil with known characteristics on its high pressure side.
If desired, what little lubricating oil that leaks past the primary seal can be collected and recirculated back to the transmitter assembly by suitable means.
The present invention has application to plunger or rod pumps of various designs and applications, and to downhole pumps that are operated by a sucker rod string which reciprocates through a stuffing box at the surface, and to many other applications.