Double-layer composite sleeve capable of sliding along axial direction and connecting method thereof
阅读说明：本技术 一种可沿轴向滑动的双层复合套管及其连接方法 (Double-layer composite sleeve capable of sliding along axial direction and connecting method thereof ) 是由 施晓哲 徐磊 于 2020-07-09 设计创作，主要内容包括：本发明涉及热力管道技术,旨在提供一种可沿轴向滑动的双层复合套管及其连接方法。该复合套管包括同轴嵌套安装的内层管和外层管；在内层管和外层管之间设置至少两组垂直于轴向的支撑滑动机构；其底端固定安装在内层管的外表面上,顶端与外层管的内壁活动连接。本发明通过内外层管道轴向滑动,可以在现有管道焊接工艺条件下,实现先对内层管焊接,再对外层管焊接,而不用现场修补管道保温层等操作,避免出现接头处结构不连续。同时,由于内外层之间采用支撑结构而非填充结构,减少了换热面积,提高了内外层之间的热阻。由于内外层之间的空间完全连通,可以进一步采用对中间抽真空,以进一步提高热阻,减少热损失。(The invention relates to a heat distribution pipeline technology, and aims to provide a double-layer composite sleeve capable of sliding along the axial direction and a connecting method thereof. The composite sleeve comprises an inner layer pipe and an outer layer pipe which are coaxially nested; at least two groups of supporting sliding mechanisms vertical to the axial direction are arranged between the inner layer pipe and the outer layer pipe; the bottom end of the inner tube is fixedly arranged on the outer surface of the inner tube, and the top end of the inner tube is movably connected with the inner wall of the outer tube. According to the invention, through axial sliding of the inner and outer pipelines, the inner pipe can be welded firstly and then the outer pipe can be welded under the existing pipeline welding process condition, operations such as repairing the pipeline heat-insulating layer on site are not needed, and the discontinuity of the structure at the joint is avoided. Meanwhile, a supporting structure rather than a filling structure is adopted between the inner layer and the outer layer, so that the heat exchange area is reduced, and the thermal resistance between the inner layer and the outer layer is improved. Because the space between the inner layer and the outer layer is completely communicated, the middle can be further vacuumized to further improve the thermal resistance and reduce the heat loss.)
1. A double-layer composite sleeve capable of sliding along the axial direction comprises an inner layer pipe and an outer layer pipe which are coaxially nested; it is characterized in that at least two groups of supporting sliding mechanisms vertical to the axial direction are arranged between the inner layer pipe and the outer layer pipe;
the supporting sliding mechanism has any one of the following structures:
(1) the supporting sliding mechanism comprises at least 3 radial supporting pieces which are uniformly arranged along the circumferential direction, each radial supporting piece comprises a supporting rod and a sliding part, the bottom end of each supporting rod is fixedly arranged on the outer surface of the inner-layer pipe, and the sliding part is arranged at the top end of each supporting rod and is connected with the inner wall of the outer-layer pipe; alternatively, the first and second electrodes may be,
(2) the supporting and sliding mechanism consists of a supporting ring and sliding parts, the bottom of the supporting ring is fixedly sleeved on the outer surface of the inner-layer pipe, and the sliding parts are uniformly arranged at the top of the supporting ring along the circumferential direction and are connected with the inner wall of the outer-layer pipe.
2. The double-layered composite bushing of claim 1, wherein the sliding member is a roller, ball bearing, or roller bearing.
3. The double-layer composite bushing of claim 1, wherein the inner and outer layers of tubes have the same axial length.
4. The double-layered composite bushing according to claim 1, wherein the number of the sliding members of each group of the supporting sliding mechanisms is equal, and the sliding members in different groups are arranged in parallel in the axial direction.
5. The double-layer composite bushing of claim 1, wherein the inner tube is a metal inner tube; the outer layer pipe is a steel pipe, a thermoplastic reinforced plastic composite pipe, a steel wire staggered reinforced polyethylene pipe or a plastic pipe; the supporting rod is made of polytetrafluoroethylene, polyphenyl ester, polyimide, polyether-ether-ketone, polyphenylene sulfide, glass wool or glass fiber.
6. The double-layered composite bushing according to claim 1, wherein the bottom ends of the support rods or rings are fixed to the outer surface of the inner tube by welding or bolting.
7. The method of joining two-layer composite sleeves of claim 1, including the steps of:
(1) transporting the double-layer composite casing to an installation site, and hoisting two adjacent sections of double-layer composite casings to be connected in place;
(2) dragging the outer layer pipe along the axial direction to make the inner layer pipe and the outer layer pipe generate dislocation and expose the interface part of the inner layer pipe to be welded;
(3) and carrying out welding operation on the inner layer pipe, and then pushing back the outer layer pipe to carry out welding operation on the outer layer pipe.
8. The method according to claim 7, wherein if the inner pipe can perform the welding operation from one side according to the requirement of the inner pipe for the welding space, the welding seam of the outer pipe is located at the same axial position as the welding seam of the inner pipe; if the inner layer pipe can not finish the welding operation from one side, the welding seam of the outer layer pipe and the welding seam of the inner layer pipe keep enough axial distance, and the inner layer pipe is ensured to have enough welding operation space.
Technical Field
The invention relates to a heat distribution pipeline technology, in particular to a double-layer composite sleeve capable of sliding along the axial direction and a connecting method thereof.
Background
The centralized heat supply has important significance for saving primary energy, improving the energy utilization efficiency, improving the life quality of residents and reducing the urban environmental pollution. The heat distribution pipeline is an important component for a central heating system to convey hot water, steam and other heating media. The heat supply pipeline is a heat supply pipeline which is started from a boiler room, a direct-fired machine room, a heat supply center and the like and leads from a heat source to a heat inlet of a building. The working pressure of the heat supply hot water medium is not higher than 2.5MPa, and the working temperature is not more than 200 ℃; the working pressure of the heat supply steam medium is not higher than 1.6MPa, and the working temperature is not higher than 350 ℃. Reducing heat loss in the heat distribution pipeline is the key to improving the heat supply network transmission efficiency and improving the efficiency of the whole heat supply system. For example, the heat supply cost of a heat supply network in a small industrial area is about 8000 ten thousand yuan per year, and about 80 ten thousand yuan can be saved by reducing the heat loss of a pipe network by 1 percent.
At present, a heat distribution pipeline mainly adopts a structural form of a multi-layer heat insulation composite pipe, namely an inner-layer metal pipe, a middle heat insulation layer and an outer-layer metal pipe. The inner layer metal pipe has the function of resisting internal pressure, the middle heat-insulating layer provides thermal resistance for the pipeline and reduces heat loss of the pipeline, and the outer layer metal pipe has the functions of protecting and bearing external pressure of soil when buried. However, such thermal insulation pipes are relatively expensive, and have large heat loss at the pipe joints and large heat loss of the whole pipes. Taking a thermal pipeline with the diameter of D600 in a certain industrial park as an example, the thickness of the thermal insulation layer of the thermal insulation pipeline reaches more than 200mm, the outer diameter of the pipeline exceeds 1 meter, the cost of the pipeline per 9 meters exceeds 10 ten thousand yuan, and the overall equivalent thermal conductivity is about 0.07 watt/(square meter DEG C). In addition, when in on-site connection, the heat-insulating layer is required to be peeled off from the finished pipe fitting, and the heat-insulating layer is coated again after the inner-layer metal pipe is welded. This operation results in a complicated procedure, time and labor consuming. If the newly coated insulating layer is not well treated, the equivalent thermal conductivity at the joint exceeds 0.2 watt/(square meter DEG C), resulting in larger heat loss.
Therefore, the invention aims to provide the heat-insulating composite pipe with the new structure, the joint connection efficiency is improved by changing the traditional composite sleeve connection mode, and the heat loss caused by the installation reason of the traditional heat supply pipeline is avoided.
Disclosure of Invention
The invention aims to solve the technical problem of overcoming the defects in the prior art and provides a double-layer composite sleeve capable of sliding along the axial direction and a connecting method thereof.
In order to solve the technical problems, the invention adopts the following solution:
the double-layer composite sleeve capable of sliding along the axial direction comprises an inner layer pipe and an outer layer pipe which are coaxially nested; at least two groups of supporting sliding mechanisms vertical to the axial direction are arranged between the inner layer pipe and the outer layer pipe;
the supporting sliding mechanism has any one of the following structures:
(1) the supporting sliding mechanism comprises at least 3 radial supporting pieces which are uniformly arranged along the circumferential direction, each radial supporting piece comprises a supporting rod and a sliding part, the bottom end of each supporting rod is fixedly arranged on the outer surface of the inner-layer pipe, and the sliding part is arranged at the top end of each supporting rod and is connected with the inner wall of the outer-layer pipe; alternatively, the first and second electrodes may be,
(2) the supporting and sliding mechanism consists of a supporting ring and sliding parts, the bottom of the supporting ring is fixedly sleeved on the outer surface of the inner-layer pipe, and the sliding parts are uniformly arranged at the top of the supporting ring along the circumferential direction and are connected with the inner wall of the outer-layer pipe.
In the present invention, the sliding member is a roller, a ball bearing or a roller bearing.
In the invention, the inner layer pipe and the outer layer pipe have the same axial length.
In the invention, the number of the sliding components of each group of supporting sliding mechanisms is equal, and the sliding components in different groups are arranged in parallel along the axial direction.
In the invention, the inner layer pipe is made of metal; the outer layer pipe is a steel pipe, a thermoplastic reinforced plastic composite pipe, a steel wire staggered reinforced polyethylene pipe or a plastic pipe; the support rod is made of Polytetrafluoroethylene (PTFE), polyphenyl ester (Ekonol), Polyimide (PI), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), glass wool or glass fiber.
In the invention, the bottom ends of the support rods or the support rings are fixed on the outer surface of the inner-layer pipe in a welding or bolt fastening mode.
The invention further provides a connecting method of the double-layer composite sleeve, which comprises the following steps:
(1) transporting the double-layer composite casing to an installation site, and hoisting two adjacent sections of double-layer composite casings to be connected in place;
(2) dragging the outer layer pipe along the axial direction to make the inner layer pipe and the outer layer pipe generate dislocation and expose the interface part of the inner layer pipe to be welded;
(3) and carrying out welding operation on the inner layer pipe, and then pushing back the outer layer pipe to carry out welding operation on the outer layer pipe.
According to the requirement of the inner layer pipe on the welding space, if the inner layer pipe can finish welding operation from one side, the welding seam of the outer layer pipe and the welding seam of the inner layer pipe are located at the same axial position; if the inner pipe cannot be welded from one side, the weld seam of the outer pipe and the weld seam of the inner pipe keep enough axial distance (i.e. dislocation), and enough welding operation space of the inner pipe is ensured.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, through axial sliding of the inner and outer pipelines, the inner pipe can be welded firstly and then the outer pipe can be welded under the existing pipeline welding process condition, operations such as repairing the pipeline heat-insulating layer on site are not needed, and the discontinuity of the structure at the joint is avoided. Meanwhile, a supporting structure rather than a filling structure is adopted between the inner layer and the outer layer, so that the heat exchange area is reduced, and the thermal resistance between the inner layer and the outer layer is improved. Because the space between the inner layer and the outer layer is completely communicated, the middle can be further vacuumized to further improve the thermal resistance and reduce the heat loss.
Drawings
FIG. 1 is a schematic view of a double-layer composite sleeve structure capable of sliding axially;
FIG. 2 is a radial cross-sectional view of the double-layer composite bushing of FIG. 1;
FIG. 3 is a schematic structural view of a double-layered composite bushing with more support structures;
FIG. 4 is a diagram of the relative position of the double-layered composite sleeve prior to installation;
fig. 5 is a schematic view of a double-layer composite bushing after welding is completed.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings.
The double-layer composite sleeve capable of sliding along the axial direction comprises an inner layer pipe 1 and an outer layer pipe 2 which are coaxially nested and installed, and the inner layer pipe and the outer layer pipe have the same axial length. At least two groups of supporting sliding mechanisms perpendicular to the axial direction are arranged between the inner layer pipe 1 and the outer layer pipe 2, and the supporting sliding mechanisms have any one of the following structures:
(1) the supporting sliding mechanism comprises at least 3 radial supporting pieces (such as 3, 4 and 6, and fig. 2 shows 4 radial supporting pieces) which are uniformly arranged along the circumferential direction, each radial supporting piece comprises a supporting rod 3 and a sliding part 4, wherein the bottom end of the supporting rod 3 is fixedly arranged on the outer surface of the inner-layer pipe 1, and the sliding part 4 is arranged at the top end of the supporting rod 3 and is connected with the inner wall of the outer-layer pipe 2; alternatively, the first and second electrodes may be,
(2) the supporting and sliding mechanism consists of a supporting ring and sliding parts, the bottom of the supporting ring is fixedly sleeved on the outer surface of the inner layer pipe 1, and the sliding parts 4 are uniformly arranged at the top of the supporting ring along the circumferential direction and are connected with the inner wall of the outer layer pipe 2.
When the inner pipe 1 is made of metal, the bottom end of the support rod 3 or the support ring is preferably fixed on the outer surface of the inner pipe 1 by welding (or fastening by bolts is also optional). The number of the slide members 4 supporting the slide mechanism is equal for each group, and the slide members 4 in different groups are arranged in parallel in the axial direction. The sliding member 4 may be selected from a roller, a ball bearing or a roller bearing for reducing sliding friction of the outer tube in the axial direction.
In the axial direction, N supporting sliding mechanisms may be arranged at equal intervals according to the requirements of the diameter and the rigidity against external pressure of the outer layer tube 2, where N is greater than or equal to 2 (fig. 1 shows a structure where N is 2, and fig. 3 shows a structure where N is 4). The supporting sliding mechanisms are distributed along the axial direction and are arranged in parallel to each other, and are used for isolating and supporting the outer layer pipe 2 and improving the external pressure resistance of the outer layer pipe 2. The space (air or vacuum) between the inner layer tube 1 and the outer layer tube 2 plays a role of heat insulation to reduce the heat transfer between the inner layer tube and the outer layer tube.
For the application occasions below 200 ℃, the support rod 3 can be selected from Polytetrafluoroethylene (PTFE), polyphenyl ester (Ekonol), Polyimide (PI), Polyetheretherketone (PEEK), polyphenylene sulfide (PPS) and other high temperature resistant and low heat conductive polymers; for the application occasions with the temperature of more than 200 ℃, the support rod 3 can be made of materials such as high-temperature resistant glass wool, glass fiber and the like.
The outer layer pipe 2 can be a steel pipe, a thermoplastic reinforced plastic composite pipe, a steel wire cross-wound reinforced polyethylene (PSP) pipe or a plastic pipe (such as a polyethylene pipe and a polypropylene pipe) and the like. The steel pipe has high rigidity and heat conductivity coefficient, and is suitable for occasions with high vacuum degree, high external pressure resistance and low requirement on the heat conductivity coefficient of the outer layer. The PSP is formed by compounding steel and plastic, has medium rigidity and small heat conductivity coefficient, and is suitable for occasions with medium external pressure resistance and certain requirements on the heat resistance of the outer pipe. The polyethylene pipe has small rigidity and small heat conductivity coefficient, and is suitable for occasions which do not require the outer layer pipe to resist external pressure but have certain requirements on heat resistance.
The invention relates to a double-layer composite sleeve capable of sliding along the axial direction, which comprises the following specific connection methods:
(1) transporting the assembled double-layer composite casing to an installation site, and hoisting two adjacent sections of double-layer composite casings to be connected in place;
(2) dragging the outer layer pipe 2 along the axial direction to make the inner layer pipe 1 and the outer layer pipe 2 dislocated, and exposing the interface part of the inner layer pipe 1 to be welded (as shown in figure 4);
(3) the inner pipe 1 is subjected to a welding operation, resulting in a
According to the requirement of the inner layer pipe 1 on the welding space, the
At this time, flanges or electric melting pipe fittings can be arranged at the end parts of the pipes in advance according to needs, the outer-layer pipes 2 are pushed back after the inner-layer pipes 1 are welded, and the outer-layer pipes are connected according to a conventional flange connection method or an electric melting welding method, which is not repeated herein.
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