| 摘要 |
A friction-reducing device for use in a well bore, the friction-reducing device being cylindrically shaped with a tapered and partially threaded upper section, cylindrical middle section, and tapered and partially threaded lower section. The middle section comprises a cylindrical outer surface, cylindrical inner surface, solid portion between the cylindrical outer surface and the cylindrical inner surface, and first plurality of friction-reducing units. The friction-reducing units are installed at equally-spaced angular intervals into ports within the solid portion of the middle section in a circular array that lies in a first plane that is perpendicular to a longitudinal axis of the cylindrical bore in the friction-reducing device. Each friction-reducing unit comprises a rear bearing seat, an array of miniature ball hearings, and a main ball bearing with a protruding portion that extends through the inner surface of the middle section into the cylindrical bore. |
| 主权项 |
1. A friction-reducing device for use in a well bore, the friction-reducing device being cylindrically shaped with a tapered and partially threaded upper section, a cylindrical middle section, and a tapered and partially threaded lower section;
wherein the middle section comprises a cylindrical outer surface, a cylindrical inner surface, a solid portion between the cylindrical outer surface and the cylindrical inner surface, and a first plurality of friction-reducing units; wherein the inner surface of the middle section forms a cylindrical bore in the center of the friction-reducing device, the cylindrical bore having a constant diameter from top to bottom; wherein the friction-reducing units are installed at equally-spaced angular intervals into ports within the solid portion of the middle section in a circular array that lies in a first plane that is perpendicular to a longitudinal axis of the cylindrical bore; wherein each friction-reducing unit comprises a rear bearing seat, an array of miniature ball bearings, and a main ball bearing with a protruding portion that extends through the inner surface of the middle section into the cylindrical bore of the friction-reducing device; wherein each port extends through the solid portion and penetrates both the outer surface and the inner surface of the middle section; wherein each port comprises a three-dimensional concave portion that penetrates the inner surface of the middle section; wherein the rear bearing seat of each friction-reducing unit comprises male threads around an outside circumference of the rear bearing seat that mate with female threads on an inside surface of the port; wherein the rear bearing sear further comprises a hex socket on an outside end of the rear bearing seat and a three-dimensional concave indentation on an inside end of the rear bearing seat; wherein the main ball bearing is positioned against the three-dimensional concave portion of the port, the three-dimensional concave portion of the port forming a front bearing seat for the main ball bearing; wherein the plurality of miniature ball bearings is situated between the three-dimensional concave indentation of the rear bearing seat and a portion of the main ball bearing that faces toward the outer surface of the middle section, and wherein the plurality of miniature ball bearings provides a low-friction rolling surface between the rear bearing seat and the main hall bearing; wherein the main ball bearing is free to rotate in any direction about any three-dimensional axis; and wherein the friction-reducing device is threadably inserted in-line between two adjacent lengths of production tubing, wherein a sucker rod is inserted through, the cylindrical bore of the friction-reducing device, and wherein the friction-reducing device maintains a gap between an inside wall of the production tubing and the sucker rod. |
