Ultra-large-diameter central thermal insulation pipe for middle-deep layer geothermal well

Abstract

The ultra-large-diameter central thermal insulation pipe comprises an outer pipe and an inner pipe which are concentrically arranged in a sleeved mode, the two ends of the inner pipe are flared and then welded to the inner wall of the outer pipe, and a sealed cavity is formed between the inner pipe wall and the outer pipe wall and kept in a vacuum state. A strip-shaped cloth bag structure wraps or spirally winds the outer wall of the inner pipe in the axis direction of the inner pipe to form a heat preservation layer, and the strip-shaped cloth bag structure is formed by alternately arranging and packaging one or more sets of reflecting layers and heat insulation layers in a heat preservation sleeve. And a plurality of annular righting reinforcing ribs are sleeved outside the thermal insulation layer at intervals. Multi-layer reflection of the heat preservation layer in the heat preservation pipe can effectively prevent heat loss, and the heat preservation effect is improved. Meanwhile, the strip-shaped cloth bag structure can prevent the aerogel powder from escaping, and the health risk of inhalable particles is reduced. In addition, gaps between the inner pipe and the outer pipe are uniformly distributed by arranging a plurality of centralizing reinforcing ribs on the outer side of the heat-insulating layer, the sealing performance of the annular space of the inner pipe and the outer pipe can be effectively maintained, a heat conduction path is cut off, and the heat-insulating effect is ensured.

Description

Technical Field

[0001] This utility model belongs to the field of thermal insulation pipe manufacturing technology, specifically relating to an ultra-large diameter central insulation pipe for medium-deep geothermal wells. Background Technology

[0002] Traditional thermal insulation pipes, due to their limited number of reflective layers, are unable to effectively block the heat transfer path, resulting in limited insulation performance and a tendency for the pipe to bend. Furthermore, their manufacturing process is complex, with long production cycles and low efficiency, hindering large-scale production. In addition, some insulation materials, such as aerogels, may generate powder during use. These fine particles are easily dispersed, potentially affecting the performance of the insulation material itself and posing potential risks to the environment and human health. In particular, long-term exposure to environments containing aerogel dust may cause respiratory discomfort or other health problems. Utility Model Content

[0003] The present invention aims to provide an ultra-large diameter central insulation pipe for medium-deep geothermal wells, which can effectively prevent heat loss and prevent aerogel powder from escaping, thereby reducing the health risks of inhalable particulate matter.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] An ultra-large diameter central insulation pipe for medium-deep geothermal wells includes an outer pipe and an inner pipe concentrically fitted together. The two ends of the inner pipe are flared and welded to the inner wall of the outer pipe, forming a sealed cavity between the inner and outer pipe walls and maintaining a vacuum state. A strip-shaped cloth bag structure is wrapped or spirally wound along the axial direction of the outer wall of the inner pipe to form an insulation layer. The strip-shaped cloth bag structure is formed by multiple layers of reflective layers and heat insulation layers arranged alternately and encapsulated in the insulation sleeve. Several annular straightening reinforcing ribs are spaced apart outside the insulation layer.

[0006] Furthermore, frustum-shaped holes are respectively opened at both ends of the outer tube, and the frustum-shaped holes are connected to the sealed cavity of the inner and outer tubes. A plug of the same specification is installed in the frustum-shaped hole, and the plug is connected to the electrode rod for vacuuming. The electrode rod is sealed and fixed to the outer wall of the outer tube by a sealing gasket. The electrode rod is hollow inside and connected to a vacuum pump at the upper end. The vacuum pump is connected to a vacuum pump to perform vacuuming treatment on the sealed cavity between the inner and outer tubes. When the predetermined vacuum degree is reached, the electrode rod is heated and the plug is melted to seal the frustum-shaped holes, thereby keeping the sealed cavity between the inner and outer tubes in a vacuum state.

[0007] Furthermore, a vertical through hole is drilled at the center of the top of the blockage, and a horizontal through hole connected to the vertical hole is opened at a position slightly below the middle of the blockage height to form a connected vacuum channel.

[0008] Furthermore, the material of the reflective layer is selected from aluminum foil, stainless steel foil, vacuum metallized paper, metallized polyester film (MPET), or metallized polypropylene film.

[0009] Furthermore, the material of the insulation layer is selected from aerogel felt, phenolic foam, fiberglass cloth or polyurethane foam.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] This invention utilizes a strip-shaped fabric bag structure, encapsulating multiple reflective and insulating layers within an insulation sleeve. This effectively prevents aerogel dispersion and reduces the health risks associated with inhalable particulate matter. The strip-shaped fabric bag structure is wound around the inner tube surface to form an insulation layer, which is then covered by an outer tube, creating a stable and reliable multi-layered insulation structure. The multi-layered reflection effectively prevents heat loss, improving insulation performance. Several reinforcing ribs are installed on the outside of the insulation layer. On one hand, this ensures the insulation pipe maintains good structural strength and stability even in ultra-large diameter applications, reducing relative deflection and precisely controlling the distance between the inner and outer tube walls, ensuring circumferential and axial uniformity. This, in turn, guarantees a uniform distribution of the gap between the inner and outer tubes and stable insulation performance. On the other hand, these reinforcing ribs can withstand significant downhole pressure and external forces, increasing structural strength and reducing the risk of pipe deformation and rupture. Simultaneously, they effectively maintain the sealing of the annular space between the inner and outer tubes, cutting off heat conduction paths and reducing heat exchange with the outside, thereby ensuring insulation performance and reducing the operational risks of the geothermal well system. Attached Figure Description

[0012] Figure 1 This is a cross-sectional structural diagram of the present invention;

[0013] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0014] Figure 3 This is a schematic diagram of the structure of the heat insulation layer and the reflective layer.

[0015] In the diagram: 1-Outer tube; 2-Inner tube; 3-Insulation layer; 31-Heat insulation layer; 32-Reflective layer; 4-Straightening and reinforcing rib; 5-Frustum hole; 6-Plug; 7-Sealing gasket; 8-Electrode rod; 9-Vacuum nozzle. Detailed Implementation

[0016] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 1As shown in the figure, the ultra-large diameter central insulation pipe for medium-deep geothermal wells described in this embodiment includes an outer pipe 1 and an inner pipe 2 concentrically arranged. The two ends of the inner pipe 2 are flared and welded to the inner wall of the outer pipe 1, forming a sealed cavity between the inner and outer pipe walls and maintaining a vacuum state. An insulation layer 3 is formed by covering or spirally winding a strip-shaped cloth bag structure along the axial direction on the outer wall of the inner pipe 2. Several annular reinforcing ribs 4 are spaced apart on the outside of the insulation layer 3. Figure 2 As shown, frustum-shaped holes 5 are respectively opened at both ends of the outer tube 1. The frustum-shaped holes 5 communicate with the sealed cavity of the inner and outer tubes. A plug 6 of the same specification is installed in the frustum-shaped hole 5. The plug 6 is connected to the electrode rod 8 for vacuuming. The electrode rod 8 is sealed and fixed to the outer wall of the outer tube 1 by a sealing flat gasket 7. The electrode rod 8 is hollow inside and the upper end is connected to a vacuum nozzle 9. A vacuum pump is connected to the vacuum nozzle 9 to perform vacuuming treatment on the sealed cavity between the inner and outer tubes. A vertical through hole is drilled at the center of the top of the plug 6, and a horizontal through hole connected to the vertical hole is opened at the lower middle part of the plug height, forming a connected vacuuming channel.

[0018] The electrode rod 8 is made of cylindrical copper material, with its lower end machined into an arc surface with the same radius as the outer end of the insulation tube, and a frustum structure reserved below this arc surface. This frustum is used to fix the sealing gasket 7, and a groove is provided in the center of the frustum to fix the plug 6. During the vacuuming operation, the plug 6 is installed in the groove at the lower end of the electrode rod 8, and the plug 6 is aligned with the frustum hole 5 on the tube body. The arc surface at the lower end of the electrode rod 8 is tightly fitted to the surface of the outer tube 1 through the sealing gasket 7 to ensure a sealing effect. The height of the electrode rod 8 is adjusted so that the plug 6 and the frustum hole 5 maintain a slight gap without contact. Then, a vacuum pump is connected through the vacuum pump nozzle 9 to evacuate the sealed cavity between the inner and outer tubes. When the vacuum level reaches the preset value, the power supply to the electrode rod 8 is turned on and pressure is applied to heat and melt the plug 6, allowing it to flow into and seal the frustum hole 5, thereby ensuring that the sealed cavity between the inner and outer tubes maintains a stable vacuum state.

[0019] The sealing gasket 7 is made of fluororubber material, which has excellent resistance to high and low temperatures, chemical corrosion and aging, and excellent vacuum sealing effect. Its structure is ring-shaped, which can be tightly attached to the lower end of the electrode rod 8 between the frustum and the surface of the outer tube 1 to form a reliable sealing interface, effectively preventing external gas from seeping into the sealing cavity between the inner and outer tubes, and ensuring the airtightness of the sealing cavity during the vacuuming process.

[0020] like Figure 3As shown, the insulation layer 3 uses one or more layers of aluminum foil as a reflective layer 32, with aerogel felt as a heat insulation layer 31 placed between each reflective layer 32. Alkali-free cloth material is placed on both the top and bottom surfaces, and the edges are sewn together to prevent interlayer slippage. It is then encapsulated in an insulation sleeve, forming a strip-shaped cloth bag structure that effectively prevents aerogel dispersion. Furthermore, the outer layer of the insulation sleeve uses a weather-resistant polyester fiber material to improve durability and resistance to external environments, ensuring the long-term stability and reliability of the insulation layer 3.

[0021] The material of the reflective layer 32 can also be one of stainless steel foil, vacuum metallized paper, metallized polyester film (MPET) or metallized polypropylene film.

[0022] The material of the insulation layer 31 can also be one of phenolic foam, fiberglass cloth or polyurethane foam.

Claims

1. A large-diameter centrally insulated pipe for medium-deep geothermal wells, characterized in that, It includes an outer tube (1) and an inner tube (2) that are concentrically fitted together. The two ends of the inner tube (2) are flared and welded to the inner wall of the outer tube (1). A sealed cavity is formed between the inner and outer tube walls and a vacuum is maintained. A strip-shaped cloth bag structure is wrapped or spirally wound on the outer wall of the inner tube (2) along its axial direction to form a heat insulation layer (3). The strip-shaped cloth bag structure is composed of one or more sets of reflective layers (32) and heat insulation layers (31) arranged alternately, and alkali-free cloth material is set on the upper and lower sides. The four sides are sewn together and sealed in the heat insulation sleeve. Several annular straightening and reinforcing ribs (4) are spaced apart on the outside of the heat insulation layer (3).

2. The ultra-large diameter central insulation pipe for medium-deep geothermal wells according to claim 1, characterized in that, A frustum hole (5) is provided at both ends of the outer tube (1). The frustum hole (5) is connected to the sealed cavity of the inner and outer tubes. A plug (6) of the same specification is provided in the frustum hole (5). The plug (6) is connected to the electrode rod (8) for vacuuming. The electrode rod (8) is sealed and fixed to the outer wall of the outer tube (1) by a sealing gasket (7). The electrode rod (8) is hollow inside and connected to a vacuum pump nozzle (9) at the upper end. A vacuum pump is connected through the vacuum pump nozzle (9) to perform vacuuming on the sealed cavity between the inner and outer tubes. When the predetermined vacuum degree is reached, the electrode rod (8) is turned on to heat and melt the plug (6) to seal the frustum hole (5), thereby keeping the sealed cavity between the inner and outer tubes in a vacuum state.

3. The ultra-large diameter central insulation pipe for medium-deep geothermal wells according to claim 2, characterized in that, A vertical through hole is drilled at the center of the top of the plug (6), and a horizontal through hole connected to the vertical hole is opened at the lower middle part of the height of the plug (6) to form a connected vacuum channel.

4. The ultra-large diameter central insulation pipe for medium-deep geothermal wells according to claim 1, characterized in that, The material of the reflective layer is selected from one of the following: aluminum foil, stainless steel foil, vacuum metallized paper, metallized polyester film (MPET), or metallized polypropylene film.

5. The ultra-large diameter central insulation pipe for medium-deep geothermal wells according to claim 1, characterized in that, The insulation layer is made of one of the following materials: aerogel felt, phenolic foam, fiberglass cloth, or polyurethane foam.

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