Prefabricated overhead steam pipe network having outer sliding self-compensation structure of thermal insulation pipe, and thermal insulation pipe manufacturing method

Abstract

Provided are a prefabricated overhead steam pipe network having an outer sliding self-compensation structure of a thermal insulation pipe, and a thermal insulation pipe manufacturing method. The method comprises the following steps: S1, welding and fixing an annular plate (5) to one end of a working steel pipe (1), and mounting an end head thermal insulation layer (2) on the working steel pipe on one side of the annular plate; S2, preparing a central thermal insulation layer (9) on the other end of the end head thermal insulation layer, and reserving a gap between the central thermal insulation layer and the end head thermal insulation layer; S3, filling an expandable pre-compressed thermal insulation material (6) in the gap; S4, mounting a prefabricated thermal insulation plug (8) on the outer side of one end of the central thermal insulation layer in a sleeving mode; and S5, sleeving an outer sleeve (4) outside the central thermal insulation layer, and performing filling and foaming in a gap between the outer sleeve and the central thermal insulation layer to form an outer thermal insulation layer (3). According to the method, compared with performing on-site thermal insulation compensation, a thermal insulation compensation structure is arranged in the thermal insulation pipe and implemented in a factory workshop, thereby ensuring the thermal insulation self-compensation of the thermal insulation pipe, and solving the problem of unreliable on-site thermal insulation compensation.

Description

Prefabricated overhead steam pipe network with external sliding self-compensating structure of insulation pipe and preparation method of insulation pipe Technical Field

[0001] The invention relates to a prefabricated overhead steam pipe network, in particular to a prefabricated overhead steam pipe network with an insulation pipe outer sliding self-compensation structure and a method for preparing the insulation pipe. Background Art

[0002] In the field of steam heating, with the continuous development of my country's economy and the increasing demand for energy conservation, especially in the context of carbon peak and carbon neutrality, prefabricated overhead steam insulated pipes are increasingly used due to their excellent thermal insulation performance and weather resistance. The China Urban Heating Association issued and implemented the group standard for this product in 2019, "TCDHA2-2019 Prefabricated Steam Insulated Pipes and Fittings for Overhead and Integrated Pipe Galleries". After years of use and accumulated experience, the technology of this product has been further improved and refined. Therefore, this group standard has been agreed to be upgraded to a national standard.

[0003] During the use of this product, due to the inconsistent expansion coefficients of the working steel pipe and the insulation material, the expansion coefficient of the steel pipe is greater than the expansion coefficient of the insulation material. Therefore, during hot operation, assuming that the operating steam temperature is 300°C, the expansion of each 12-meter insulation pipe is about 40mm, and the expansion of a long straight pipeline of about 120 meters is about 400mm; at the same time, there are currently two operating modes for prefabricated overhead pipes: internal sliding and external sliding; when the operating mode is internal sliding, the expansion of all steam steel pipes is uniformly compensated at the connection between the end of the pipeline and the compensator, and the compensation amount is 400mm; when the operating mode is external sliding, the expansion of each insulation pipe is compensated at the interface of each pipe, and the compensation amount is 40mm.

[0004] Regardless of the compensation method used, current practices require the installation of compensation mechanisms during on-site insulation of the interfaces. However, because interfaces are fabricated by on-site workers, quality control and material shaving can be problematic, making proper installation of compensation mechanisms impossible. This can create insulation gaps. Actual on-site testing often reveals relatively high-temperature circumferential cracks at the interfaces, indicating that the insulation layer in this section has been torn and ineffectively compensated, significantly increasing heat loss. On-site insulation compensation often fails to achieve the desired effect, leading to significantly increased heat loss in the pipeline that goes undetected.

[0005] Summary of the Invention

[0006] In response to the shortcomings of existing insulation compensation technology and on-site construction, the present invention provides a prefabricated overhead insulation pipe external sliding self-compensation structure. By changing the manufacturing method of the insulation compensation of the external sliding insulation pipe, the insulation compensation structure is arranged inside the insulation pipe and produced in the factory workshop, thereby ensuring the insulation self-compensation of the insulation pipe and solving the problem of unreliable on-site insulation compensation in the above background.

[0007] The specific plan is as follows:

[0008] A prefabricated overhead steam pipe network with an insulated pipe external sliding self-compensating structure, the prefabricated overhead steam pipe network includes a plurality of composite insulated pipes connected end to end, the composite insulated pipes include a working steel pipe, the outer diameter of the working steel pipe is provided with a central insulation layer, an outer insulation layer and an outer sleeve in sequence from the inside to the outside, end insulation layers are provided at both ends of the central insulation layer and are sleeved on the working steel pipe, an annular plate is fixedly installed at both ends of the working steel pipe and is located between the end insulation layer and the end face of the central insulation layer, one side of the annular plate is in contact with the end insulation layer, and the other side has a gap with the end face of the central insulation layer and is filled with expandable pre-compressed insulation material, and the expandable pre-compressed insulation material compensates for the gap formed between the central insulation layer and the end insulation layer after the working steel pipe expands due to heat.

[0009] Furthermore, the expandable pre-compressed thermal insulation material is glass wool.

[0010] Furthermore, the central insulation layer is composed of multiple inner insulation layers;

[0011] The end insulation layer is a sleeve with multiple steps in the axial direction. Each step corresponds to an inner insulation layer in the axial direction. A gap is left between each step and the end face of the inner insulation layer and is filled with expandable pre-compressed insulation material.

[0012] Furthermore, the ring plate is flush with the inner step close to the working steel pipe.

[0013] Furthermore, the outer surface of the expandable pre-compressed thermal insulation material is wrapped with an annular steel plate, and both ends of the annular steel plate are overlapped and covered on the outer surfaces of the end thermal insulation layer and the central thermal insulation layer.

[0014] Furthermore, a prefabricated insulation plug is provided between the central insulation layer and the end face of the outer sleeve, and the outer insulation layer is a foamed polyurethane foam layer.

[0015] The preparation method of the above-mentioned prefabricated overhead steam pipe network comprises the following steps:

[0016] S1. Welding and fixing the ring plate on the working steel pipe, and installing the end insulation layer on the side of the ring plate close to the end of the working steel pipe;

[0017] S2. Prepare a central insulation layer on the other side of the end insulation layer, leaving a gap between the central insulation layer and the end insulation layer;

[0018] S3, filling the gap with expandable pre-compressed thermal insulation material;

[0019] S4. Install a prefabricated insulation plug on the outer diameter of one end of the central insulation layer;

[0020] S5. Place the outer sleeve outside the central insulation layer, and inject foam into the gap between the outer sleeve and the central insulation layer to form an outer insulation layer.

[0021] The above-mentioned preparation method also includes:

[0022] After the expandable pre-compressed thermal insulation material is filled, an annular steel plate is wrapped around the outer surface of the expandable pre-compressed thermal insulation material, and both ends of the annular steel plate are overlapped and covered on the outer surface of the end insulation layer and the center insulation layer.

[0023] The advantages of the present invention are:

[0024] 1) A gap is left between the end surfaces of the end insulation layer and the center insulation layer and filled with expandable pre-compressed insulation material. During hot operation, the gap is stretched by half the expansion of the working steel pipe. At this time, the compressed expandable pre-compressed insulation material rebounds and fills the gap. This ensures that the insulation gap caused by thermal expansion is always filled with glass wool, and thermal expansion joints are eliminated.

[0025] 2) Compared with solving the insulation layer compensation on site, the present invention sets the insulation compensation structure inside the insulation pipe and produces it in the factory workshop, thereby ensuring the insulation self-compensation of the insulation pipe, solving the problem of unreliable on-site insulation compensation in the above background. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] FIG1 is a schematic cross-sectional view of one end of a single insulated pipe of a prefabricated overhead steam pipe network provided by the present invention;

[0028] Figures 2 to 8 are flow charts for preparing an insulation pipe with an external sliding self-compensating structure according to the present invention; wherein,

[0029] FIG2 is a schematic diagram of installing a ring plate on a working steel pipe;

[0030] FIG3 is a schematic diagram of installing an end insulation layer on a working steel pipe on one side of a ring plate;

[0031] Figure 4 is a schematic diagram of preparing a central insulation layer on the working steel pipe on one side of the ring plate, with a gap reserved between the central insulation layer and the end surface of the end insulation layer and filled with expandable pre-compressed insulation material;

[0032] FIG5 is a schematic diagram of installing a prefabricated insulation plug at the end of the central insulation layer;

[0033] FIG6 is a schematic diagram of an expandable pre-compressed thermal insulation material coated with a thin steel plate;

[0034] FIG7 is a schematic diagram of placing an outer sleeve outside the central insulation layer and pouring foam inside to form an outer insulation layer;

[0035] FIG8 is a schematic diagram of a self-compensating structure prepared on the other end of the working steel pipe using the same process. DETAILED DESCRIPTION

[0036] In the following description, numerous specific details are provided to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without one or more of these details. In other instances, certain technical features well known in the art are not described to avoid confusion with the present invention.

[0037] In order to fully understand the present invention, detailed steps and detailed structures will be presented in the following description to illustrate the technical solution of the present invention. Preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0038] As shown in Figure 1, the present invention provides a prefabricated overhead steam pipe network with an external sliding self-compensating structure of an insulation pipe. The prefabricated overhead steam pipe network is formed by connecting a number of composite insulation pipes end to end. The composite insulation pipe includes a working steel pipe 1. A ring plate 5 is welded on the outer diameter of the working steel pipe 1. The working steel pipe 1 on the left side of the ring plate 5 is wrapped with an end insulation layer 2, and a central insulation layer 9 is wrapped on the right side of the ring plate 5. A designed gap is reserved between the end insulation layer 2 and the central insulation layer 9, and is filled with expandable pre-compressed insulation material 6. An outer insulation layer 3 and an outer sleeve 4 are provided outside the central insulation layer 9. Preferably, the material of the expandable pre-compressed insulation material 6 is glass wool, which is low in cost, easy to compress, and has certain expansion properties after being compressed for a short time.

[0039] This product's structure is as shipped. During hot operation, the central insulation layer 9 aligns with the center of expansion of the working steel pipe 1. The end insulation layer 2, pushed by the ring plate 5, moves with the expanded end of the working steel pipe 1. The gap between the end insulation layer 2 and the central insulation layer 9 is filled with expandable, pre-compressed insulation material 6. During hot operation, this gap is stretched by half the expansion of the working steel pipe 1. The glass wool, briefly compressed, then rebounds and fills the gap. This ensures that the insulation gap caused by thermal expansion is always filled with glass wool, eliminating thermal expansion joints in the insulation layer. Furthermore, the end insulation layer 2 maintains consistent displacement with the end of the working steel pipe 1, preventing any noticeable increase in the head of the working steel pipe 1 (the distance between the end of the working steel pipe 1 and the insulation head). This ensures that the insulation dimension of the pipe joint does not increase, maintaining the same length as during cold construction. This technical solution enables self-compensation of insulation in prefabricated overhead insulated pipes. The additional heat loss caused by the annular gap of the insulation layer is eliminated.

[0040] In an optional embodiment, the central insulation layer 9 is composed of multiple inner insulation layers 9-1, and the end insulation layer 2 is a sleeve with multiple axial steps 2-1. Each step 2-1 corresponds to a layer of inner insulation layer 9-1 in the axial direction. A gap is left between each step 2-1 and the end surface of the inner insulation layer 9-1 and is filled with expandable pre-compressed insulation material 6. The ring plate 5 is flush with the innermost step near the working steel pipe 1.

[0041] In an optional embodiment, the outer surface of the expandable pre-compressed thermal insulation material 6 is wrapped with a thin steel plate 7. The thin steel plate 7 has a certain width, and the two ends of the thin steel plate 7 overlap and cover the outer surface of the end insulation layer 2 and the central insulation layer 9. There is a certain distance between the two ends of the thin steel plate 7 and the expandable pre-compressed thermal insulation material 6, so that no matter how much the end insulation layer 2 is displaced, the thin steel plate 7 always completely covers the expanded expandable pre-compressed thermal insulation material 6. When multiple layers of expandable pre-compressed thermal insulation material 6 are provided between the end insulation layer 2 and the central insulation layer 9, the steel plate 7 only needs to be wrapped around the outermost layer of expandable pre-compressed thermal insulation material 6. Since the remaining expandable pre-compressed thermal insulation material 6 is located in the central insulation layer 9, it is not necessary to wrap it with a steel plate.

[0042] In an optional embodiment, a prefabricated insulation plug 8 is provided between the central insulation layer 9 and the end surface of the outer sleeve 4, and the outer insulation layer 3 is a foamed polyurethane foam layer.

[0043] As shown in Figures 2 to 8, the preparation method of the present invention comprises the following steps:

[0044] S1. Weld the ring plate 5 to the working steel pipe 1, as shown in FIG2 ; wrap the end insulation layer 2 on the left side of the working steel pipe 1, as shown in FIG3 .

[0045] S2. Prepare a central insulation layer 9 on the right side of the ring plate 5, and reserve a designed gap between the central insulation layer 9 and the end insulation layer 2.

[0046] S3. Fill the gap with expandable pre-compressed thermal insulation material (glass wool) 6, as shown in FIG4 .

[0047] S4. Install a prefabricated insulation plug 8 on the outer diameter of one end of the central insulation layer 9, as shown in Figure 5. Then wrap a steel plate 7 on the outer surface of the expandable pre-compressed insulation material 6, with the two ends of the steel plate 7 overlapping and covering the outer surface of the end insulation layer 2 and the central insulation layer 9, as shown in Figure 6.

[0048] S5. The outer sleeve 4 is placed outside the central insulation layer 9, and the interlayer between the outer sleeve 4 and the central insulation layer 9 is foamed by pouring to form an outer insulation layer 3, as shown in FIG7 .

[0049] Finally, both ends of the working steel pipe 1 are operated in this way, and the finished pipe formed has an external sliding self-compensating structure at both ends, as shown in FIG8 .

[0050] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-mentioned disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention that do not depart from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A prefabricated overhead steam pipe network with an external sliding self-compensation structure for a heat-insulating pipe. The prefabricated overhead steam pipe network includes a number of composite heat-insulating pipes connected end to end. The composite heat-insulating pipe includes a working steel pipe (1). An inner heat-insulating layer (9), an outer heat-insulating layer (3), and an outer sleeve pipe (4) are sequentially arranged on the outer diameter of the working steel pipe (1) from inside to outside. End heat-insulating layers (2) sleeved on the working steel pipe (1) are provided at both ends of the inner heat-insulating layer (9). It is characterized in that, Ring plates (5) are fixedly installed at both ends of the working steel pipe (1) between the end insulation layer (2) and the end face of the central insulation layer (9). One side of the ring plate (5) abuts against the end insulation layer (2), and there is a gap between the other side and the end face of the central insulation layer (9), which is filled with expandable pre-compressed insulation material (6).

2. The prefabricated overhead steam pipe network with an external sliding self-compensation structure for a heat-insulating pipe as claimed in claim 1, characterized in that The expandable pre-compressed insulation material (6) is glass wool.

3. The prefabricated overhead steam pipe network with an external sliding self-compensation structure for a heat-insulating pipe as claimed in claim 1, wherein The central insulation layer (9) is composed of multiple layers of inner insulation layers (9-1). The end insulation layer (2) is a sleeve with multiple levels of steps axially provided. Each level of step corresponds to one layer of inner insulation layer (9-1) in the axial direction. There is a gap between each level of step (2-1) and the end face of the inner insulation layer (9-1), which is filled with the expandable pre-compressed insulation material (6).

4. The prefabricated overhead steam pipe network with an externally sliding self-compensating structure for a heat-insulating pipe according to claim 3, characterized in that, The ring plate (5) is flush with the inner layer step close to the working steel pipe (1).

5. The prefabricated overhead steam pipe network with an external sliding self-compensation structure for a heat-insulating pipe according to claim 1, characterized in that, The outer surface of the expandable pre-compressed insulation material (6) is wrapped with a ring-shaped steel plate (7). The two ends of the ring-shaped steel plate (7) overlap and cover the outer surfaces of the end insulation layer (2) and the central insulation layer (9).

6. The prefabricated overhead steam pipe network with an external sliding self-compensation structure for a heat-insulating pipe according to claim 1, wherein, A prefabricated insulation plug (8) is provided between the end face of the central insulation layer (9) and the outer sleeve (4). The outer insulation layer (3) is a foamed polyurethane foam layer.

7. A preparation method of a prefabricated overhead steam pipe network according to any one of claims 1-6, characterized in that, The preparation method steps include: S1. Weld and fix the ring plate (5) on the working steel pipe (1), and install the end insulation layer (2) on one side of the ring plate (5) close to the end of the working steel pipe (1). S2. Prepare the central insulation layer (9) on the other side of the end insulation layer (2), and leave a gap between the central insulation layer (9) and the end insulation layer (2). S3. Fill the expandable pre-compressed insulation material (6) in the gap. S4. Install the prefabricated insulation plug (8) on the outer diameter of one end of the central insulation layer (9). S5. Sleeve the outer sleeve (4) outside the central insulation layer (9), and pour foam in the gap between the outer sleeve (4) and the central insulation layer (9) to form the outer insulation layer (3). It also includes:

8. The preparation method according to claim 7, characterized in that, After filling the expandable pre-compressed insulation material (6), wrap the outer surface of the expandable pre-compressed insulation material (6) with a ring-shaped steel plate (7). The two ends of the ring-shaped steel plate (7) overlap and cover the outer surfaces of the end insulation layer (2) and the central insulation layer (9). ​

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