| 摘要 |
A packing assembly provides a seal for an annular space between a pump plunger and a pump body of a reciprocating plunger pump. The pumping assembly includes an elastomeric header ring disposed in a high pressure end of the annular space for preventing migration of fluid through the annular space due to radial compression of the header ring. At least one V-shaped packing ring is disposed in the annular space behind the header ring and has a concave side thereof facing the header ring. A female adapter ring is disposed in the annular space behind a last V-shaped packer ring. A V-shaped anti-extrusion ring is disposed in the annular space between the last V-shaped packing ring and the female adapter for preventing extrusion of the last V-shaped packing ring between the female adapter and each of the pump plunger and the pump body. The present invention relates generally to packings for use in an annular packing space between a first cylindrical member which reciprocates within a cylindrical bore of a second member, and more particularly, but not by way of limitation, to such packing sets specifically designed for use in sealing the high pressure ends of a reciprocating plunger pump utilized for pumping cement slurries, fracturing slurries, acids and the like for the completion and stimulation of wells in the oil and gas industry. During the completion and/or stimulation of an oil or gas well, fluids such as cement slurries, fracturing slurries, acids and the like are pumped under pressure into the well. Very high pressures on the order of many thousands of pounds per square inch are typically involved in these pumping operations. Additionally, the fluids are often very abrasive because they carry large quantities of solid particles therein. This pumping operation is typically achieved by large positive displacement reciprocating plunger-type pumps. A very difficult sealing problem is encountered at the high pressure end of these pumps, where the abrasive fluid must be prevented from leaking between the reciprocating plunger and the cylinder within which it reciprocates. Typically, the seal between the reciprocating plunger and the cylinder comprises a packing arrangement including a plurality of V-shaped packing rings constructed of cloth and binder, with various male and female adapters at the forward and rearward ends of those packing sets. A longitudinal compression is applied to the packing set by an adjusting ring. Problems encountered in the use of such packing include the deterioration of the V-shaped cloth and binder packing rings due to the hydraulic load from the high pressure fluid end of the pump. A second problem typically encountered is extrusion of the V-shaped cloth and binder packing rings between the small annular clearances present between a female adapter supporting the rearward end of the packing rings and the pump plunger and pump cylinder. The prior art has included the use of header rings for providing a primary seal between the plunger and cylinder. The prior art has also included various anti-extrusion devices for preventing extrusion of the packing rings when subjected to high pressures. The present invention provides a particularly effective combination of a header ring, a packing ring means, and a V-shaped anti-extrusion ring means. The particular combination of the present invention has been found to provide operating lifetimes of the packing sets substantially in excess of the lifetimes experienced with typical prior art packings. The packing assembly of the present invention provides a means for sealing an annular space between a pump plunger and a pump body of a reciprocating plunger pump. The assembly includes a radially compressed elastomeric header ring means disposed in a high pressure end of the annular space for preventing migration of fluid through the annular space. A packing ring means is disposed in the annular space behind the header ring means, and includes at least one V-shaped packing ring with a concave side thereof facing the header ring means. A female adapter ring is disposed in the annular space behind a last V-shaped packing ring of the packing ring means. A V-shaped anti-extrusion ring means is disposed in the annular space between the last V-shaped packing ring and the female adapter. The anti-extrusion ring means provides a means for preventing extrusion of the last V-shaped packing ring between the female adapter and each of the pump plunger and the pump body. The anti-extrusion ring means includes a concave side engaging the last V-shaped packing ring and a convex side engaging a forward concave side of the female adapter. The anti-extrusion ring means further includes radially inner and outer sealing surfaces for engaging the pump plunger and the pump body, respectively.
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