A new protective device for the external thread of the pipe end of the petroleum oil well steel pipe

Abstract

The invention provides a novel protective device for pipe end external threads of a petroleum well steel pipe. The protective device is provided with a steel ring housing and a plastic protective ring, wherein a plurality of overflow holes are uniformly formed in the circumference of the steel ring housing; the plastic protective ring is arranged in the steel ring housing; the plastic protective ring and the steel ring housing are subjected to once injection moulding and are further riveted and fastened by feed liquid overflowed from the overflow holes; and internal threads adapted to the pipe end external threads of the petroleum well steel pipe are formed in the internal circumference surface of the plastic protective ring. According to the novel protective device, the multiple overflow holes are uniformly formed in the steel ring housing, and the plastic protective ring and the steel ring housing are subjected to once injection moulding and are riveted and fastened by the feed liquid overflowed from the overflow holes, so that a binding force between the steel ring housing and the plastic protective ring is increased greatly. In addition, the internal threads in the internal circumference of the plastic protective ring are also subjected to once injection moulding, and no subsequent turning procedure is required, so that the production cost is lowered greatly.

Description

technical field [0001] The invention belongs to the technical field of oil well steel pipe protection, and in particular relates to a new type of protection device for the external thread of the oil well steel pipe end. Background technique [0002] The closest existing technology to the present invention is the patent document with the patent number "ZL201120568749.8" and the patent title "The external thread protection device for the end of the oil well steel pipe". The technical scheme of this document is realized in this way: The inner circle of the housing is fitted with a matching plastic protective ring. The inner circle of the plastic protective ring is provided with internal threads that match the external threads of the oil well steel pipe end. The outer circle of the plastic protective ring is axially Reinforcing ribs are formed, and grooves are formed on the reinforcing ribs, and protrusions are formed on the inner wall of the steel ring shell, and the protrusion...

AI Technical Summary

Problems solved by technology

It is difficult to fix the steel and plastic, causing them to spin around each other during use

In daily use, steel parts often fall off by themselves, which cannot provide proper protection, and there are potential safety hazards. The solution is usually to increase the thickness of steel plates and plastic parts to increase strength, but the fundamental problem has not been effectively solved; The second is that after the inner wall of the plastic part is threaded, the plastic part shrinks in addition to the longitudinal shrinkage, especially in the axial direction, and the thread pitch changes.

Therefore, large-sized threaded plastic parts must be threaded after aging, and the thread cannot be injected at one time, which increases the process and cost, resulting in a sharp increase in production costs, so it is necessary to propose improvements

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