Air drilling double-wall drill rod

Abstract

The invention discloses an air drilling double-wall drill rod, consisting of an external pipe body and an internal pipe body. The upper end part of the external pipe body is provided with an internalscrew thread and an internal clamp table; the lower end part of the external pipe body is provided with an external screw thread, wherein the nominal diameter, the dentoform and the thread pitch of the external screw thread are as the same as those of the internal screw thread at the upper end part, and the screw thread length of the external screw thread is equal to that of the internal screw thread at the upper end part; the upper end part of the internal pipe body is fixedly provided with a pipe sleeve type internal pipe joint; a pipe body in the lower part of the internal pipe joint is fixedly provided with a ventilate pan which is matched with the inner diameter of the internal clamp table of the external pipe body, wherein the outer diameter of the internal pipe joint is less than the inner diameter of the external pipe body; the internal pipe body is hanged in the external pipe body by the ventilate pan thereof; the upper end face of the internal pipe joint is parallel with theupper end face of the external pipe body; the lower end face of the internal pipe body enters into the internal pipe joint of the other internal pipe body and is butt joint with the upper end face ofthe other internal pipe body when the external screw thread at the lower end part of the external pipe body is screwed into the internal screw thread of the other external pipe body; and the externalperipheral face of the internal pipe body is sealed with the internal peripheral face of the internal pipe joint of the other internal pipe body. The air drilling double-wall drill rod is convenient in maintenance.

Description

technical field [0001] The invention relates to an air-drilling double-wall drill pipe, in particular to an air-drill double-wall drill pipe with an inner pipe body and an outer pipe body separated. Background technique [0002] At present, the air-drilling double-walled drill pipe in the prior art has an inner pipe body and an outer pipe body which are fixed together as an integrated air-drilled double-walled drill pipe. The disadvantages of this type of air-drilled double-wall drill pipe are that the structure is complex, the precision is high, and the processing technology is cumbersome. The mating surface needs to be heat-treated to improve wear resistance, and the manufacturing cost is high; The third is that the service life is short, maintenance is difficult, and it cannot be repaired at the construction site, and only in a professional maintenance factory can it be repaired. The direct result of above all shortcoming is exactly to delay construction period, and cons...

AI Technical Summary

Problems solved by technology

The disadvantages of this type of air-drilled double-wall drill pipe are that the structure is complex, the precision requirements are high, and the processing technology is cumbersome. The mating surface needs to be heat-treated to improve wear resistance, and the manufacturing cost is high; kg; thirdly, the service life is short, maintenance is difficult, and it cannot be repaired at the construction site, only in professional maintenance manufacturers.

The direct result of the above-mentioned shortcomings is that the construction period is delayed and the construction cost is high.

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