Thermofluid pipe expander with thermal insulation

Abstract

The application relates to the technical field of heat pipe expansion joints, in particular to a heat pipe expansion joint with a heat insulation layer, which comprises an internal flow guide, a flexible compensation assembly, an external protective shell, a multilayer heat insulation assembly, a fixed connecting piece and a breathable moisture-proof device. The internal flow guide and the flexible compensation assembly cooperatively realize displacement absorption, the external protective shell and the multilayer heat insulation assembly cooperatively reduce heat conduction, and the fixed connecting piece and the breathable moisture-proof device improve the sealing property and stability. The application significantly improves the heat insulation performance, reduces heat loss, enhances safety, reduces maintenance cost through optimization of structure design and material selection, and is suitable for high-temperature working conditions, thereby providing reliable support for efficient energy saving and safe operation of a heat pipe network system.

Description

Technical Field

[0001] This utility model belongs to the field of thermal pipeline technology, specifically a thermal pipeline expansion joint with a heat insulation layer. Background Technology

[0002] In heating pipe networks, pipes expand and contract due to temperature changes in the medium. Expansion joints, as core components for absorbing axial displacement, are widely used to prevent pipe damage caused by stress concentration. However, existing expansion joints still have shortcomings under high-temperature conditions. For example, ordinary expansion joints lack insulation on their outer shells, allowing heat to easily conduct outwards, resulting in energy loss and impacting the operation of surrounding equipment and personnel safety.

[0003] A search revealed a thermal pipe expansion joint with publication number CN112178340B, published on October 25, 2022. This design achieves deformation compensation through structures such as tension springs and connecting rods, and prevents slippage by increasing the friction between the bellows and the thermal pipe. However, it does not address thermal insulation optimization; in high-temperature environments, the metal casing can easily conduct heat to the external environment, potentially impacting the safety of surrounding equipment and personnel. Furthermore, its applicability in scenarios with large temperature differences or prolonged high temperatures remains unclear.

[0004] A search revealed a composite bidirectional compensator with publication number CN102147038B, published on July 25, 2012. This design achieves bidirectional displacement compensation through components such as bellows and outer casing, and incorporates an insulation layer to reduce heat loss. However, it primarily focuses on internal heat retention, with insufficient optimization of the outer casing's insulation performance. During long-term high-temperature operation, heat conduction may still impact the external environment, and the structure is relatively complex, resulting in high maintenance costs.

[0005] The above indicates that the thermal insulation performance and safety of traditional thermal pipeline expansion joints under high-temperature conditions still have room for improvement. Therefore, this invention aims to provide a thermal pipeline expansion joint with an insulation layer to meet the requirements of high efficiency, energy saving, and safe operation. Utility Model Content

[0006] This utility model relates to a thermal pipeline expansion joint with a heat insulation layer, aiming to solve the problems of energy loss, impact on the operation of surrounding equipment, and safety hazards caused by heat conduction in existing expansion joints under high-temperature conditions. Through optimized structural design and material selection, it provides a highly efficient, energy-saving, and safe expansion joint solution.

[0007] The technical solution of this utility model includes the following components: an internal flow guide, a flexible compensation component, an external protective shell, a multi-layer heat insulation component, a fixing connector, and a breathable and moisture-proof device. The specific structure of each component and their interconnection relationship are described below:

[0008] 1. Internal airflow guide

[0009] The internal flow guide is a hollow cylindrical tubular structure, with both ends rigidly connected to external equipment via flanges. This flow guide is made of high-temperature resistant alloy material, and its inner wall is mirror-polished to reduce flow resistance. An annular groove is located in the center of the flow guide for installing a flexible compensation component. The depth and width of the annular groove are precisely machined according to the dimensions of the flexible compensation component to ensure a tight fit and prevent seal failure due to relative displacement caused by thermal expansion and contraction.

[0010] 2. Flexible compensation components

[0011] The flexible compensation component is composed of multiple layers of corrugated sheets, each layer being a continuous sinusoidal wave shape, and fixedly connected by spot welding. The corrugated sheets are made of a high-temperature resistant nickel-based alloy, possessing excellent fatigue resistance and corrosion resistance. Both ends of the flexible compensation component are welded to annular grooves in the internal flow guide, forming a closed cavity. This cavity can absorb axial displacement caused by temperature changes, while simultaneously compensating for radial displacement through the elastic deformation of the corrugated sheets.

[0012] 3. External protective casing

[0013] The outer protective shell is a hollow cylindrical structure, coaxially enclosing the internal flow guide. Both ends of the shell are securely connected to fixing connectors via bolts, forming a complete sealed space. The inner wall of the shell is equipped with multiple longitudinal reinforcing ribs to enhance the overall structural rigidity and compressive strength. The number and distribution of these reinforcing ribs are optimized according to actual operating conditions to balance weight and strength.

[0014] 4. Multi-layer thermal insulation components

[0015] The multi-layer thermal insulation assembly is installed on the outer surface of the external protective shell and consists of three functional layers stacked sequentially. The first layer is an insulating fiber layer, made of high-density ceramic fiberboard, fixed to the shell surface with adhesive. The second layer is a supporting frame layer, composed of a honeycomb mesh structure made of high-temperature resistant composite material, connected to the first layer by embedded clips. The third layer is an outer protective coating, formed on the surface of the supporting frame layer using a spraying process to create a corrosion-resistant and high-temperature resistant polytetrafluoroethylene film. The three layers work together to effectively reduce the rate of heat conduction to the external environment while maintaining the overall lightweight and stability of the structure.

[0016] 5. Fixed connectors

[0017] The fixed connectors are located at both ends of the outer protective housing and are rigidly connected to the flanges of the internal flow guide components via bolts. A sealing gasket, made of graphite, is installed on the inner side of the connector, providing excellent high-temperature resistance and sealing performance. The thickness and compression of the sealing gasket are precisely calculated to ensure stable sealing even under high-temperature conditions. Furthermore, multiple through holes are provided on the outer side of the fixed connector for mounting tie rod assemblies, further enhancing the overall structural stability.

[0018] 6. Breathable and moisture-proof device

[0019] The breathable and moisture-proof device is located at the top and bottom of the outer protective shell and consists of multiple microporous breathable units. Each breathable unit includes a metal base and an embedded microporous membrane made of polytetrafluoroethylene (PTFE), which has excellent breathability and waterproof performance. The breathable units are fixed to the shell surface by threaded connections, facilitating future maintenance and replacement. The function of this device is to balance the air pressure inside and outside the shell, preventing condensation buildup caused by temperature differences, thereby ensuring the long-term stable performance of the thermal insulation components.

[0020] Technical principles and combination relationships

[0021] This invention achieves high-efficiency thermal insulation performance and safe operation through the rational design and combination of the above-mentioned components. The combination of internal flow guides and flexible compensation components ensures the smooth absorption of displacement during thermal expansion and contraction; the cooperation between the external protective shell and multi-layer thermal insulation components significantly reduces the rate of heat conduction outward; and the introduction of fixed connectors and breathable moisture-proof devices further enhances the overall structure's sealing performance and reliability.

[0022] The beneficial effects of this utility model are reflected in the following aspects:

[0023] 1. Improved thermal insulation performance: The layered design of the multi-layer thermal insulation components effectively blocks heat conduction, significantly reduces heat loss, and thus improves energy utilization efficiency.

[0024] 2. Enhanced safety: The surface temperature of the outer protective housing is significantly reduced, avoiding the risk of burns to operators upon contact, and also reducing the thermal impact on surrounding equipment.

[0025] 3. Strong structural stability: Through the synergistic effect of flexible compensation components and external protective shell, the overall structure has high pressure resistance and fatigue resistance, and can meet the needs of large temperature difference and long-term high temperature operation.

[0026] 4. Ease of maintenance: The multi-layer insulation components and the breathable and moisture-proof devices are all modularly designed, which can be quickly disassembled and replaced, reducing maintenance costs and time.

[0027] In summary, this utility model solves the problems of insufficient thermal insulation performance, poor safety, and inconvenient maintenance in the prior art by optimizing the overall structural design and material selection of the expansion joint, and provides reliable technical support for the efficient energy saving and safe operation of the heating pipeline network system. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention, showing the assembly relationship of the internal flow guide, flexible compensation component, external protective shell and multi-layer heat insulation component.

[0029] Figure 2 This is a cross-sectional view of the present invention, which focuses on showing the connection between the annular groove of the internal flow guide and the flexible compensation component, as well as the distribution of reinforcing ribs in the external protective shell.

[0030] Figure 3 This is a schematic diagram of the layered structure of a multi-layer thermal insulation component, which shows in detail the composition and connection relationship of the thermal insulation fiber layer, the supporting frame layer and the outer protective coating.

[0031] Figure 4 This is a partial enlarged view of the breathable and moisture-proof device, showing the structure of the microporous breathable unit and its installation method on the outer protective shell.

[0032] The attached figures are labeled as follows:

[0033] 1. Internal airflow guide; 2. Flexible compensation component; 3. External protective shell; 4. Multi-layer thermal insulation component; 5. Fixing connector; 6. Breathable and moisture-proof device; 7. Thermal insulation fiber layer; 8. Support frame layer; 9. External protective coating; 10. Microporous breathable unit. Detailed Implementation

[0034] This utility model provides a thermal pipeline expansion joint with a heat insulation layer. Its structural design, the connection relationships, positional relationships, and mutual cooperation relationships between its components will be described in detail below. (See attached diagram.) Figure 1 To be continued Figure 4 And the parts numbered 1 to 10 in the attached diagram, the specific implementation methods are as follows:

[0035] The overall structure of the thermal pipeline expansion joint is as follows: Figure 1As shown, the expansion joint includes an internal flow guide 1, a flexible compensation component 2, an external protective shell 3, a multi-layer thermal insulation component 4, a fixed connector 5, and a breathable and moisture-proof device 6. These components are assembled in a specific manner to form a complete thermal pipeline expansion joint. The internal flow guide 1 is a hollow cylindrical tubular structure with flanges at both ends for rigid connection to external equipment. An annular groove is machined in the middle of the internal flow guide 1 for installing the flexible compensation component 2. The depth and width of the annular groove are precisely machined according to the specific dimensions of the flexible compensation component 2 to ensure a tight fit between the two. The flexible compensation component 2 is composed of multiple layers of corrugated sheets, each layer of which is in the shape of a continuous sine wave. The layers of corrugated sheets are fixedly connected by spot welding. The two ends of the flexible compensation component 2 are welded into the annular groove of the internal flow guide 1 to form a closed cavity for absorbing axial and radial displacement caused by temperature changes.

[0036] The outer protective shell 3 is a hollow cylindrical structure, coaxially covering the exterior of the internal flow guide 1. Both ends of the outer protective shell 3 are fastened to the fixing connector 5 with bolts, forming a complete sealed space. The inner wall of the outer protective shell 3 is provided with multiple longitudinal reinforcing ribs, the number and distribution of which are optimized to balance weight and strength. A multi-layer thermal insulation assembly 4 is installed on the outer surface of the outer protective shell 3, consisting of three functional layers stacked sequentially. The first layer is an insulating fiber layer 7, made of high-density ceramic fiberboard and fixed to the surface of the outer protective shell 3 with adhesive. The second layer is a supporting frame layer 8, composed of a honeycomb mesh structure made of high-temperature resistant composite material, connected to the insulating fiber layer 7 by embedded clips. The third layer is an outer protective coating 9, formed by spraying a polytetrafluoroethylene film onto the surface of the supporting frame layer 8. The three layers work together to reduce the rate of heat transfer to the external environment while maintaining the overall lightweight and stability of the structure.

[0037] Fixed connectors 5 are located at both ends of the outer protective housing 3 and are rigidly connected to the flanges of the internal guide component 1 via bolts. A sealing gasket, made of graphite, is installed on the inner side of the fixed connector 5. The thickness and compression of this gasket are precisely calculated to ensure a stable seal even under high-temperature conditions. Furthermore, multiple through holes are provided on the outer side of the fixed connector 5 for installing tie rod assemblies, further enhancing the overall structural stability. A breathable and moisture-proof device 6 is located at the top and bottom of the outer protective housing 3 and consists of multiple microporous breathable units 10. Each microporous breathable unit 10 includes a metal base and an embedded microporous membrane made of polytetrafluoroethylene (PTFE). The microporous breathable units 10 are fixed to the surface of the outer protective housing 3 via threaded connections, facilitating future maintenance and replacement.

[0038] The connection relationship between the internal flow guide 1 and the flexible compensation component 2 is as follows: Figure 2 As shown, the annular groove of the internal flow guide 1 and the corrugated sheet of the flexible compensation component 2 are fixed by welding to ensure a tight fit between the two. The flexible compensation component 2 forms a closed cavity within the annular groove of the internal flow guide 1. The cavity design allows the flexible compensation component 2 to absorb axial and radial displacements during thermal expansion and contraction. The reinforcing ribs inside the outer protective shell 3 are distributed as follows... Figure 2 As shown, the reinforcing ribs are arranged longitudinally along the inner wall of the shell, and their quantity and position are optimized to enhance the overall rigidity and compressive strength of the outer protective shell 3.

[0039] The layered structure of the multi-layer thermal insulation component 4 is as follows: Figure 3 As shown, the thermal insulation fiber layer 7 is fixed to the surface of the outer protective shell 3 by an adhesive, the support frame layer 8 is connected to the thermal insulation fiber layer 7 by embedded buckles, and the outer protective coating 9 is applied to the surface of the support frame layer 8 by a spraying process. The combination of the thermal insulation fiber layer 7, the support frame layer 8, and the outer protective coating 9 effectively reduces the rate of heat conduction to the outside while maintaining the lightweight and stability of the overall structure.

[0040] A partial enlarged view of the breathable and moisture-proof device 6 is shown below. Figure 4 As shown, the microporous ventilating unit 10 is fixed to the surface of the outer protective shell 3 via a threaded connection. The metal base of the microporous ventilating unit 10 is fixed to the surface of the outer protective shell 3 via a threaded connection, and the microporous membrane is embedded in the metal base to ensure stable installation of the ventilating unit. The function of the ventilating and moisture-proof device 6 is to balance the air pressure inside and outside the outer protective shell 3, prevent condensation from accumulating due to temperature differences, and thus ensure the long-term performance stability of the multi-layer thermal insulation component 4.

[0041] The working principle of the thermal pipeline expansion joint is as follows: When the medium flows in the thermal pipeline, the internal flow guide 1 reduces the flow resistance of the medium through its high-temperature resistant alloy material and mirror-polished inner wall. The flexible compensation component 2 absorbs the axial and radial displacement caused by temperature changes through the elastic deformation of its multi-layer corrugated sheets, ensuring the smooth operation of the thermal pipeline during thermal expansion and contraction. The outer protective shell 3 enhances the rigidity and compressive strength of the overall structure through its multiple longitudinal reinforcing ribs, and achieves a rigid connection with the flange of the internal flow guide 1 through the fixed connector 5, ensuring the sealing of the overall structure. The multi-layer heat insulation component 4 reduces the rate of heat conduction to the outside through its three-layer functional design, thereby reducing heat loss. The ventilated and moisture-proof device 6 balances the air pressure inside and outside the outer protective shell 3 through its microporous ventilated unit 10, preventing condensation accumulation and ensuring the long-term stable performance of the multi-layer heat insulation component 4.

[0042] In practical applications, this invention is suitable for thermal pipeline systems operating under high-temperature conditions. For example, in industrial thermal pipelines, this invention significantly reduces heat loss and improves energy utilization efficiency through its high-efficiency insulation performance and safe operation capabilities. Simultaneously, the surface temperature of its outer protective shell 3 is significantly reduced, avoiding the risk of burns to operators upon contact and minimizing the thermal impact on surrounding equipment. Furthermore, the modular design of this invention allows for quick disassembly and replacement of the multi-layer insulation component 4 and the breathable moisture-proof device 6, reducing maintenance costs and time.

[0043] To enable those skilled in the art to fully understand and implement this utility model, the following supplementary explanation of the specific implementation principle of this utility model is provided in conjunction with a specific application scenario.

[0044] In industrial heating network systems operating at high temperatures, expansion joints are installed between two adjacent sections of heating pipe to absorb axial and radial displacements caused by temperature changes. Their operation involves the following steps:

[0045] First, when the high-temperature medium begins to flow in the heating pipeline, the internal flow guide 1 reduces the flow resistance through its high-temperature resistant alloy material and mirror-polished inner wall, ensuring smooth flow. At this time, due to the high temperature of the medium, the design of the annular groove of the internal flow guide 1 tightly fitting the flexible compensation component 2 plays a crucial role. The flexible compensation component 2 is composed of multiple layers of corrugated sheets, each layer being a continuous sine wave shape, and fixedly connected by spot welding. This structural design allows the flexible compensation component 2 to undergo elastic deformation during thermal expansion and contraction, thereby absorbing axial and radial displacements caused by temperature changes. Through this deformation, the flexible compensation component 2 effectively avoids pipeline damage caused by thermal stress concentration, ensuring the heating pipeline remains stable during operation.

[0046] Secondly, the outer protective shell 3 enhances the rigidity and compressive strength of the overall structure through its multiple longitudinal reinforcing ribs. These reinforcing ribs are arranged longitudinally along the inner wall of the shell, and their number and distribution are optimized to balance the relationship between weight and strength. The two ends of the outer protective shell 3 are fastened to the fixing connector 5 with bolts, forming a complete sealed space. A graphite sealing gasket is installed on the inner side of the fixing connector 5, with its thickness and compression precisely calculated to ensure a stable sealing effect even under high-temperature conditions. Furthermore, multiple through holes are provided on the outer side of the fixing connector 5 for installing tie rod assemblies, further enhancing the stability of the overall structure. This sealing and reinforcement design effectively prevents leakage of high-temperature media and ensures the reliability of the expansion joint during long-term high-temperature operation.

[0047] Next, the multi-layer insulation component 4 plays a significant role in heat insulation. The insulation fiber layer 7 is made of high-density ceramic fiberboard and is fixed to the surface of the outer protective shell 3 with adhesive. The support frame layer 8 is composed of a honeycomb mesh structure made of high-temperature resistant composite material and is connected to the insulation fiber layer 7 by embedded clips. The outer protective coating 9 is a polytetrafluoroethylene film formed on the surface of the support frame layer 8 using a spraying process. The three-layer structure works together to effectively reduce the rate of heat conduction to the outside. The insulation fiber layer 7 blocks heat through its high-density properties, the support frame layer 8 provides mechanical support through its honeycomb mesh structure, and the outer protective coating 9 protects the entire insulation component through its corrosion resistance and high-temperature resistance. This layered design not only reduces heat loss but also maintains the lightweight and stability of the overall structure.

[0048] Subsequently, the breathable and moisture-proof device 6 balances the air pressure inside and outside the outer protective shell 3 through its microporous breathable units 10, preventing condensation buildup caused by temperature differences. Each microporous breathable unit 10 includes a metal base and a microporous membrane embedded therein, the membrane being made of polytetrafluoroethylene (PTFE). The microporous breathable unit 10 is fixed to the surface of the outer protective shell 3 by a threaded connection, facilitating future maintenance and replacement. The function of the breathable and moisture-proof device 6 is to ensure the balance of air pressure inside and outside the outer protective shell 3, while preventing moisture from entering the multi-layer thermal insulation component 4, thereby ensuring its long-term stable performance.

[0049] Finally, when the temperature of the medium inside the heating pipe changes, the flexible compensation component 2 absorbs the axial and radial displacement caused by the temperature change through the elastic deformation of its multi-layer corrugated sheets, ensuring the smooth operation of the heating pipe during thermal expansion and contraction. The outer protective shell 3 enhances the rigidity and compressive strength of the overall structure through its multiple longitudinal reinforcing ribs, and achieves a rigid connection with the flange of the internal flow guide 1 through the fixed connector 5, ensuring the sealing of the overall structure. The multi-layer heat insulation component 4 reduces the rate of heat conduction to the outside through its three-layer functional design, thereby reducing heat loss. The breathable and moisture-proof device 6 balances the air pressure inside and outside the outer protective shell 3 through its microporous breathable unit 10, preventing condensation accumulation and ensuring the long-term stable performance of the multi-layer heat insulation component 4.

[0050] Through the above steps, this invention achieves high-efficiency thermal insulation performance and safe operation. In practical applications, this invention is suitable for thermal pipeline systems under high-temperature conditions. For example, in industrial thermal pipelines, this invention significantly reduces heat loss and improves energy utilization efficiency through its high-efficiency thermal insulation performance and safe operation. Simultaneously, the surface temperature of its outer protective shell 3 is significantly reduced, avoiding the risk of burns to operators upon contact and reducing the thermal impact on surrounding equipment. Furthermore, the modular design of this invention allows for quick disassembly and replacement of the multi-layer thermal insulation component 4 and the breathable moisture-proof device 6, reducing maintenance costs and time.

[0051] In summary, this utility model, through the rational design and combination of its components, solves the problems of insufficient thermal insulation performance, poor safety, and inconvenient maintenance in the prior art, providing reliable technical support for the efficient energy saving and safe operation of the heating pipeline network system.

Claims

1. A thermal pipeline expansion joint with a heat insulation layer, characterized in that, include: Internal flow guide (1) is a hollow cylindrical tubular structure with flanges at both ends; The flexible compensation component (2) is composed of multiple corrugated sheets stacked together and fixedly connected by spot welding. The two ends of the flexible compensation component (2) are welded to the annular groove in the middle of the internal flow guide (1). The outer protective shell (3) is a hollow cylindrical structure and coaxially covers the outside of the internal flow guide (1). The inner wall of the outer protective shell (3) is provided with multiple longitudinal reinforcing ribs. The multi-layer heat insulation component (4) is installed on the outer surface of the outer protective shell (3) and is composed of heat insulation fiber layer (7), support frame layer (8) and outer protective coating (9) stacked in sequence. The fixed connector (5) is set at both ends of the outer protective shell (3) and is rigidly connected to the flange of the internal flow guide (1) by bolts. The breathable and moisture-proof device (6) is arranged at the top and bottom of the outer protective shell (3) and is composed of multiple microporous breathable units (10).

2. The thermal pipeline expansion joint with insulation layer according to claim 1, wherein, The internal guide component (1) is made of high temperature resistant alloy, and the inner wall is mirror polished. The depth and width of the annular groove in the middle are precisely processed according to the size of the flexible compensation component (2).

3. The thermal pipeline expansion joint with insulation layer according to claim 1, wherein, The corrugated sheet of the flexible compensation component (2) is in the shape of a continuous sine wave and is made of high temperature resistant nickel-based alloy. The two ends of the flexible compensation component (2) are fixed in the annular groove of the internal guide component (1) by welding.

4. The thermal pipeline expansion joint with insulation layer according to claim 1, wherein, The number and distribution of longitudinal reinforcing ribs of the outer protective shell (3) have been optimized. The two ends of the outer protective shell (3) are fastened to the fixed connector (5) by bolts.

5. The thermal pipeline expansion joint with insulation layer according to claim 1, wherein, The insulation fiber layer (7) of the multi-layer insulation component (4) is a high-density ceramic fiber board and is fixed to the surface of the outer protective shell (3) by an adhesive. The support frame layer (8) is a honeycomb grid structure and is connected to the insulation fiber layer (7) by an embedded buckle. The outer protective coating (9) is a polytetrafluoroethylene film and is covered on the surface of the support frame layer (8) by a spraying process.

6. The thermal pipeline expansion joint with insulation layer according to claim 1, wherein, The inner side of the fixed connector (5) is provided with a graphite sealing gasket. The thickness and compression of the sealing gasket are precisely calculated. The outer side of the fixed connector (5) is provided with a through hole for installing the tie rod assembly.

7. The thermal pipeline expansion joint with insulation layer according to claim 1, wherein, The microporous breathable unit (10) of the breathable and moisture-proof device (6) includes a metal base and a microporous membrane embedded therein. The microporous membrane is made of polytetrafluoroethylene. The microporous breathable unit (10) is fixed to the surface of the outer protective shell (3) by a threaded connection.

8. The thermal pipeline expansion joint with insulation layer according to claim 1, wherein, The annular groove of the internal flow guide (1) and the corrugated sheet of the flexible compensation component (2) are welded together to achieve a tight fit. The flexible compensation component (2) forms a closed cavity in the annular groove of the internal flow guide (1).

9. The thermal pipeline expansion joint with insulation layer according to claim 1, wherein, The longitudinal reinforcing ribs inside the outer protective shell (3) are arranged longitudinally along the inner wall of the shell, and their number and position are optimized to enhance the overall rigidity and compressive strength of the outer protective shell (3).

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