| 摘要 |
"OIL WELL SUCKER ROD COUPLING ASSEMBLY' A sucker rod coupling assembly is provided for connecting a pair of sucker rods and centralizing the rods in a tubing string. The coupling assembly finds particular application in connection with a rotating rod string driving an oil well downhole screw pump. The coupling assembly comprises a cylindrical solid steel shaft having externally threaded pin ends. A tubular sleeve or layer formed of nonmetallic soft resilient abrasion-resistant material, such as polyurethane, is bonded to the surface of the shaft and extends its full length between the pin ends. A pair of internally threaded steel sucker rod box couplings is also provided. The box couplings are provided to interconnect the shaft with the pair of sucker rods. The shaft end face of each box coupling has a ring of soft resilient abrasionresistant material bonded thereto. A tubular externally fluted centralizer, formed of the same material, fits loosely around the shaft. The centralizer has a snug fit in the tubing and is frictionally gripped so as to be stationary in use. One or more notches extend transversely across the upper end face of the centralzer, to permit fluid flow therethrough so that the centralizer does not seal against the coupling above it. The polyurethane layers on the shaft and coupling end faces protect the steel parts of the coupling assembly against severe abrasion wear from sand particles proceeding through the annular clearance between the centrailzer and the shaft. By providing a non-rotating non-metallic centralizer at the locus of the large diameter box ends, wear of the tubing wall is substantially reduced.
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