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CN-224229560-U - Structure for freely extending inner pipe of central heat preservation pipe of middle-deep geothermal well

CN224229560UCN 224229560 UCN224229560 UCN 224229560UCN-224229560-U

Abstract

The utility model discloses a free extension structure of an inner pipe of a central insulating pipe of a middle-deep geothermal well, which comprises an outer pipe and an inner pipe which are sleeved concentrically, wherein one end of the inner pipe is welded and fixed on the outer wall of the other end of the outer pipe, a compression ring is arranged on the outer wall of the other end of the inner pipe, a gap is reserved between the compression ring and the outer pipe, a positioning ring is fixed on the inner wall of the outer pipe at the same end, a plurality of fluorine rubber sealing rings are arranged between the positioning ring and the compression ring, one end of the inner pipe drives the compression ring to expand or contract along the axial direction when the temperature changes, the sealing rings are compressed through the compression ring when the inner pipe contracts, and the sealing rings are limited and restrained by the positioning ring, so that the contraction amount of the inner pipe is ensured to be within a design allowable range. The utility model can ensure free expansion and contraction of the inner tube along with the temperature change of the internal fluid, avoid the stress between the inner tube and the outer tube, and simultaneously prevent the outer tube from bending deformation or crack failure due to the stress, thereby avoiding the risk of quality accidents.

Inventors

  • LI YONGLI
  • LIU WENJING
  • ZHENG CHENGJIE
  • XIONG XIN

Assignees

  • 西安润威恒泰地热管技术有限公司

Dates

Publication Date
20260512
Application Date
20250625

Claims (6)

  1. 1. The structure is characterized by comprising an outer pipe (1) and an inner pipe (2) which are sleeved concentrically, wherein one end of the inner pipe (2) is welded and fixed on the outer pipe (1), a compression ring (5) is arranged on the outer wall of the other end part of the inner pipe (2), a gap is reserved between the compression ring (5) and the outer pipe (1), a positioning ring (4) is fixed on the inner wall of the outer pipe (1) at the same end, and a plurality of fluorine rubber sealing rings (6) are arranged between the positioning ring (4) and the compression ring (5); When the temperature changes, one end of the inner tube (2) drives the compression ring (5) to expand or shrink along the axial direction, and when the inner tube (2) shrinks, the compression ring (5) compresses the sealing ring (6), and the sealing ring (6) is limited and restrained by the positioning ring (4), so that the shrinkage of the inner tube (2) is ensured to be within a design allowable range.
  2. 2. The structure of the free extension of the inner pipe of the central insulating pipe of the middle-deep geothermal well according to claim 1, wherein the compression ring (5) is connected with the inner pipe (2) through a screw thread.
  3. 3. The structure of the free extension of the inner pipe of the central insulating pipe of the middle-deep geothermal well according to claim 1, wherein the outer diameter of the sealing ring (6) is slightly larger than the gap between the outer pipe (1) and the inner pipe (2), and the elastic sealing is realized through interference fit.
  4. 4. The structure of the free extension of the inner pipe of the central insulating pipe of the middle and deep geothermal well according to claim 1, wherein one end of the outer pipe (1) and one end of the inner pipe (2) are welded, and a spacing ring (3) is arranged between the outer pipe (1) and the inner pipe (2) as a welding carrier to fix one end of the inner pipe (2) on the outer pipe (1).
  5. 5. A free extension structure of an inner pipe of a central insulating pipe of a deep geothermal well according to any one of claims 1 to 4, characterized in that a heat insulating layer is provided in the cavity between the outer pipe (1) and the inner pipe (2).
  6. 6. The free-extending structure of an inner pipe of a central insulating pipe of a mid-deep geothermal well according to claim 5, wherein the insulating layer comprises a combination of one or more materials selected from aluminum foil, aerogel and fiberglass.

Description

Structure for freely extending inner pipe of central heat preservation pipe of middle-deep geothermal well Technical Field The utility model belongs to the technical field of manufacturing of heat insulation pipes, and particularly relates to a free extension structure of an inner pipe of a central heat insulation pipe of a middle-deep geothermal well. Background In order to cope with the thermal stress caused by the temperature difference between the outer pipe and the inner pipe in the underground working condition in the manufacturing process of the geothermal heat-insulating pipe, the inner pipe is usually pre-applied with larger stress to weld the two ends of the inner pipe and the outer pipe in production, but the method brings adverse effects that the outer pipe is easy to bend due to the fact that the inner pipe and the outer pipe are inconsistent in shrinkage at normal temperature due to the larger pre-stress, the quality of products is affected, the difficulty in thread processing is increased, the yield is reduced, and in addition, the thermal stress distribution of each pipe section is uneven due to the fact that the depths of different pipe sections in the well are different, the temperatures of the different pipe sections are different. The same batch of heat-insulating pipes cannot adjust pre-stressing according to different depths of the lower well, so that the difference exists between the load born by the pipe body and the load born by the welding spots, and fatigue damage can be caused when the load is serious, so that the whole service life and the operation reliability of the heat-insulating pipes are affected. Disclosure of utility model The utility model aims to provide a structure for freely extending an inner pipe of a central heat-insulating pipe of a middle-deep geothermal well, which can ensure that the inner pipe is free to expand and contract with heat along with the temperature change of internal fluid, avoid the stress generated between the inner pipe and the outer pipe, and simultaneously prevent the outer pipe from bending deformation or crack failure due to the stress, thereby avoiding the risk of quality accidents. In order to achieve the above purpose, the present utility model provides the following technical solutions: The inner pipe free extension structure of the central heat preservation pipe of the middle-deep geothermal well comprises an outer pipe and an inner pipe which are sleeved concentrically, wherein one end of the inner pipe is welded and fixed on the outer pipe, a compression ring is arranged on the outer wall of the other end of the inner pipe, a gap is reserved between the compression ring and the outer pipe, a positioning ring is fixed on the inner wall of the outer pipe at the same end, a plurality of fluorine rubber sealing rings are arranged between the positioning ring and the compression ring, one end of the inner pipe drives the compression ring to expand or contract along the axial direction when the temperature changes, the sealing rings are compressed through the compression ring when the inner pipe contracts, and the sealing rings are limited and restrained by the positioning ring, so that the contraction amount of the inner pipe is ensured to be within a design allowable range. Further, the compression ring is connected with the inner pipe through threads. Furthermore, the sealing ring is slightly larger than the gap between the outer pipe and the inner pipe, and elastic sealing is realized through interference fit. Further, one end of the outer tube and one end of the inner tube are welded, and a spacing ring serving as a welding carrier is arranged between the outer tube and the inner tube to fix one end of the inner tube on the outer tube. Further, a heat insulation layer is arranged in the cavity between the outer pipe and the inner pipe. Further, the heat insulation layer comprises one or more materials selected from aluminum foil, aerogel and glass fiber. Compared with the prior art, the utility model has the following beneficial effects: According to the utility model, one end of the inner pipe of the heat-insulating pipe is fixed on the outer pipe, and the other end of the inner pipe can be freely stretched, so that the straightness of the heat-insulating pipe can be controlled within 2 per mill, and the heat-insulating pipe has the advantages of high production efficiency and low energy consumption, and is more suitable for well descending operation. Specifically, a compression ring is arranged at one movable end of the inner pipe, a positioning ring is arranged on the inner wall of the outer pipe at the same end, and a sealing ring is arranged between the inner pipe and the outer pipe to ensure that the cavity is closed and cut off a heat energy convection path. When the temperature changes, one end of the inner tube which can move drives the compression ring to expand or contract along the axial direction, and meanwhile, when the