Electromagnetic induction heating air pipe structure for special coating cabin of ship

Abstract

This utility model discloses an electromagnetic induction heating duct structure for special-coated ship compartments, including an air supply duct with an electromagnetic induction heating coil mounted on it. The air supply duct is made of a magnetically conductive material and is placed in a modular compartment. The modular compartment also includes a cooling system for the air supply duct body. An airflow equalization device is provided on the inner wall of the air supply duct. This utility model is based on the principle of electromagnetic induction, resulting in high heating efficiency. A high-frequency current passes through the coil to generate an alternating magnetic field, which excites free electrons within the metal wall of the duct to generate eddy currents. These eddy currents overcome resistance and convert work into heat energy, directly heating the duct wall. The heat energy is transferred to the airflow within the duct through heat conduction, avoiding the inefficient conversion path of traditional electric heating tubes: "electrical energy → radiant energy → air heat energy". Furthermore, it adopts a modular design with high integration. The device is integrated into a box-type modular structure, with the air supply duct and blower housed within the box module. The structure is compact, facilitating installation and maintenance.

Description

Technical Field

[0001] This utility model relates to the field of special coating equipment for ships, specifically to an electromagnetic induction heating air duct structure for special coating cabins of ships. Background Technology

[0002] In the application of electromagnetic induction heating in specially coated compartments of ships, existing electromagnetic induction heating duct technology faces the dual challenges of insufficient cooling efficiency and uneven airflow organization. Because electromagnetic induction coils inevitably generate Joule heat loss during high-frequency operation, traditional cooling methods often rely on independent axial fans or natural ventilation. This decoupling of the heat dissipation path from the heating process leads to coil temperatures easily exceeding the temperature resistance limit of the insulation material. Heat accumulation in the duct body under low-flow conditions can cause metal material degradation, and electronic control components frequently malfunction due to delayed heat dissipation. These problems not only increase the risk of equipment short circuits and structural deformation but also often lead to the failure of high-performance coatings (such as Marineline 784) to cure due to construction interruptions, requiring costly rework and significantly increasing construction costs and safety hazards.

[0003] Meanwhile, existing duct inner wall guiding structures often fail to fully consider the synergy between electromagnetic induction eddy current effects and airflow characteristics. Common straight blade or smooth inner wall designs struggle to effectively overcome the thermal resistance of the airflow boundary layer, resulting in uneven temperature distribution within the chamber, with outlet temperature differences exceeding ±5℃, failing to meet the stringent temperature and humidity requirements for coating application. While simply increasing airflow velocity can enhance turbulence, it significantly increases pressure loss, causing a surge in fan energy consumption, creating a technical bottleneck where uniformity and energy efficiency are difficult to balance.

[0004] In the existing operating mode, the cooling system and the heating process are independent of each other. Heat dissipation relies on post-event remediation rather than real-time dynamic control, which not only occupies extra space but also makes it difficult to cope with complex working conditions. Furthermore, the energy efficiency advantage of electromagnetic induction heating is further weakened due to the material selection (such as the magnetic interference of ordinary steel and the insufficient thermal conductivity of plastic materials) and layout defects in the flow guiding structure. This leads to industry pain points such as long construction cycle, high energy consumption, and unstable coating quality in special coating projects. Utility Model Content

[0005] The purpose of this utility model is to overcome the defects in the existing technology and provide an electromagnetic induction heating air duct structure for special coating cabins of ships. It aims to address the inherent defects of the existing technology by integrating the cooling structure and the airflow guiding system to achieve synergistic optimization of thermal management and airflow organization, thereby fundamentally improving the reliability, energy efficiency and construction adaptability of the electromagnetic induction heating air duct.

[0006] To achieve the above objectives, the technical solution of this utility model is as follows: an electromagnetic induction heating air duct structure for special coating compartments of ships, including an air supply duct, an electromagnetic induction heating coil on the air supply duct, the air supply duct being made of a magnetically conductive material, and the air duct being placed in a modular compartment, the modular compartment also including a cooling system for the air supply duct body; the inner wall of the air supply duct is provided with an airflow homogenization device.

[0007] Furthermore, the cooling system is a forced air cooling system, including a cooling fan and a vent installed on the side wall of the module compartment. The cooling fan is a driving device that establishes forced airflow circulation within the module compartment.

[0008] Furthermore, the cooling system is a built-in fluid cooling system, which includes a spiral cooling channel provided inside or on the surface of the air duct body, and a cooling medium flows through the spiral cooling channel.

[0009] Furthermore, the spiral cooling channel is a fluid pipe made of a non-magnetic material.

[0010] Furthermore, the spiral cooling channel is wound in the same direction as the electromagnetic induction heating coil on the air supply pipe, and the pitch matches the coil spacing.

[0011] Furthermore, the cooling system includes a necked section and an outer sleeve disposed on the air supply duct. The outer sleeve is coaxially sleeved on the cooling part of the air supply duct, so that a cooling duct is formed between the air supply duct and the outer sleeve. One end of the cooling duct is a closed end and the other end is an open end. The closed end is connected to the air supply duct inside the necked section.

[0012] Furthermore, a controllable opening and closing device is provided at the connection point between the closed end of the outer sleeve and the air supply pipe.

[0013] Furthermore, the airflow homogenization device includes longitudinal ribs arranged along the axial direction of the air supply duct, with multiple longitudinal ribs circumferentially distributed on the inner wall of the air supply duct and parallel to the airflow direction.

[0014] Furthermore, the inlet end of the air supply duct is provided with an airflow distribution cone, which is placed on the axis of the air supply duct, with the tip of the airflow distribution cone pointing towards the airflow inlet end.

[0015] Furthermore, the airflow homogenization device includes turbulence protrusions disposed on the inner wall of the air supply duct. The turbulence protrusions are hemispherical protrusions that protrude from the inner wall of the air supply duct, and a number of turbulence protrusions are evenly distributed at intervals on the inner wall of the air supply duct.

[0016] The advantages and beneficial effects of this utility model are as follows: 1. This utility model has high heating efficiency based on the principle of electromagnetic induction. The high-frequency current generates an alternating magnetic field through the coil, which excites the free electrons in the metal wall of the air duct to generate eddy currents. The eddy currents overcome the resistance and do work to convert into heat energy, which directly heats the air duct wall. The heat energy is transferred to the airflow in the air duct through heat conduction, avoiding the inefficient conversion path of "electrical energy → radiation energy → air heat energy" of traditional electric heating tubes.

[0017] 2. Modular design with high integration: The device is integrated into a box-type modular structure, with air supply pipes and blowers inside the box modules. The structure is compact and easy to install and maintain.

[0018] 3. This device is equipped with a dedicated cooling system, which solves the problem of insufficient heat dissipation from the air duct due to reduced blower airflow, thus affecting the precise temperature control inside the special coating compartment. The cooling system has multiple implementation methods, which can be selected according to actual conditions to achieve more accurate temperature control. Attached Figure Description

[0019] Figure 1 This is an isometric view of the box-type module of this utility model;

[0020] Figure 2 This is a longitudinal cross-sectional schematic diagram of the modular compartment with an air supply duct in this utility model;

[0021] Figure 3 This is an isometric view of the air supply duct in this utility model;

[0022] Figure 4 This is one of the longitudinal cross-sectional schematic diagrams of the air supply duct in this utility model;

[0023] Figure 5 This is the second longitudinal cross-sectional schematic diagram of the air supply duct in this utility model;

[0024] In the diagram: 1. Air supply duct; 2. Electromagnetic induction heating coil; 3. Module compartment; 4. Cooling system; 5. Airflow equalization device; 6. Cooling fan; 7. Ventilation outlet; 8. Spiral cooling channel; 9. Neck section; 10. Outer casing; 11. Cooling duct; 12. Closed end; 13. Connecting pipe; 14. Opening and closing device; 15. Longitudinal ribs; 16. Airflow distribution cone; 17. Turbulence protrusion; 18. Open end; 19. Box-type module; 20. Blower. Detailed Implementation

[0025] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0026] An electromagnetic induction heating duct structure for a specially coated ship compartment, such as Figure 1-5 As shown, the device includes an air supply duct 1. Based on the principle of electromagnetic induction, an electromagnetic induction heating coil 2 is installed on the air supply duct 1. Figure 2 As shown, this device is integrated into a box-type module 19 structure. The box-type module 19 is equipped with an air supply pipe 1 and a blower 20. The outlet end of the blower 20 is connected to the air supply pipe 1. The air supply pipe 1 is separated into a separate module compartment 3 in the box-type module 19 by a partition, while the blower 20 is set in another adjacent compartment. The blower 20 draws in external air and sends it into the special coating compartment of the target ship through the air supply pipe 1.

[0027] Based on the principle of electromagnetic induction heating, a high-frequency current generates an alternating magnetic field through a coil. Free electrons within the metal wall of the duct are excited by the magnetic field, generating eddy currents. These eddy currents overcome resistance and convert their work into heat energy (Joule effect), directly heating the duct wall. The heat energy is transferred to the airflow within the duct through heat conduction, avoiding the inefficient conversion path of traditional electric heating elements: "electrical energy → radiant energy → air heat energy". The air supply duct 1 needs to be made of a magnetically conductive material. In this embodiment, carbon steel is used as an example, meaning the air supply duct 1 is made of carbon steel. Of course, other materials can also be used, such as silicon steel, manganese steel, ferrite materials, etc. The air supply duct 1 is placed inside the module compartment 3, which also includes a cooling system 4 for the air supply duct 1 body. An airflow equalization device 5 is provided on the inner wall of the air supply duct 1. Because precise temperature control is required within the target coating chamber, when the temperature inside the chamber is about to reach the set threshold, the airflow of the blower 20 must be reduced. Correspondingly, the power of the electromagnetic induction heating coil 2 is also reduced. However, the heat accumulated inside the air duct 1 cannot be dissipated in time due to the reduced airflow of the blower 20, causing the temperature of the air duct 1 to gradually rise. Furthermore, its temperature drop also requires a certain amount of time, which affects the precise temperature control within the coating chamber. Therefore, this embodiment includes a dedicated cooling system 4 for the air duct 1 to solve the above problems.

[0028] As one embodiment, the cooling system 4 is a forced air cooling system, such as... Figure 2 As shown, the module includes a cooling fan 6 and a vent 7 installed on the side wall of the module compartment 3. The cooling fan 6 is a drive device for establishing forced airflow circulation within the module compartment 3. Since the air supply duct 1 has an independent module compartment 3 within the box-type module 19, an air inlet and outlet structure is provided on the side wall of the compartment based on this structure. Specifically, the cooling fan 6 forces air into the module compartment 3, and the supplied air flows out through the vent 7, thereby establishing forced airflow circulation within the module compartment 3. The relatively cool external air cools the air supply duct 1, preventing it from overheating.

[0029] In another embodiment, the cooling system 4 is a built-in fluid cooling system 4, which includes a spiral cooling channel 8 disposed inside or on the surface of the air duct 1, such as... Figure 4 As shown, a cooling medium flows through the spiral cooling channel 8. Furthermore, to avoid the spiral cooling channel 8 affecting the magnetic field formed by the electromagnetic induction heating coil 2 and thus affecting the heating efficiency of the air supply pipe 1, the spiral cooling channel 8 is made of a fluid pipe made of a non-magnetic material.

[0030] Furthermore, the spiral cooling channel 8 is wound in the same direction as the electromagnetic induction heating coil 2 on the air supply duct 1, and the pitch matches the coil spacing. The electromagnetic induction heating coil 2 is arranged as follows: the coil is spirally wound along the axial direction of the air supply duct 1, with the spacing gradually decreasing from the inlet to the outlet (e.g., 80mm at the inlet and 50mm at the outlet) to compensate for heat loss after the airflow heats up. The coil ends are connected to the inverter via high-frequency cables, with insulated ceramic terminals at the interface, having a withstand voltage ≥1000V, ensuring that the alternating magnetic field generated by the coil penetrates the air duct to the maximum extent and excites strong eddy currents. Specifically, the air supply duct 1 uses a DN500mm diameter and a 4mm wall thickness to ensure effective heating, adapt to mainstream special-coated cabin ventilation duct diameters, and ensure an airflow matching 12000m³ / h. In this embodiment, by setting a spiral cooling channel 8 inside or on the surface of the air supply duct 1, a low-temperature fluid (cooling water in this embodiment) is used to circulate and remove heat from the duct wall, while simultaneously forming a thermo-magnetic decoupling with the external electromagnetic induction coil, ensuring that the magnetic field only acts on the metal wall of the air duct. In this embodiment, the spiral channel is aligned with the coil winding direction, either clockwise or counterclockwise, and the pitch matches the coil spacing, such as a coil spacing of 50-80mm and a channel pitch of 60mm.

[0031] In another embodiment, specifically, the cooling system 4 includes a necked section 9 and an outer casing 10 disposed on the air supply duct 1, such as... Figure 5As shown, the outer sleeve 10 is coaxially sleeved on the cooling part of the air supply pipe 1, so that a cooling duct 11 is formed between the air supply pipe and the outer sleeve 10. One end of the cooling duct 11 is a closed end 12 and the other end is an open end 18. The closed end 12 is connected inside the air supply pipe 1 at the necking section 9. Because a constriction section 9 is provided on the air supply duct 1, both ends of the constriction section 9 are relatively large expansion sections. Therefore, the gas velocity increases and the pressure decreases within the constriction section 9. The constriction section 9 is connected to the closed end 12 of the outer casing duct 10 through the connecting pipe 13. The low pressure formed at the constriction section 9 drives the airflow within the cooling duct 11, drawing the gas from the open end 18 into the cooling duct 11, thereby air-cooling the surface of the air supply duct 1. It is worth noting that the advantage of this embodiment is that it does not require an external cooling fan 6, but relies on the negative pressure generated by the airflow of the blower 20 to drive the gas flow within the cooling duct 11. Therefore, it relies on the stable airflow established within the supply duct, making this embodiment more suitable. During the air supply phase, when the electromagnetic induction heating coil 2 reaches the threshold temperature, a stable airflow is maintained in the air supply duct 1. The negative pressure established by the constriction section 9 cools the heated area. Furthermore, a controllable opening and closing device 14 is provided at the connection between the closed end 12 of the outer sleeve 10 and the air supply duct 1. Specifically, a dedicated connecting pipe 13 can be provided on the constriction section 9. Multiple connecting pipes 13 can be arranged circumferentially, and the other end of the multiple connecting pipes 13 is connected to the closed end 12. When the cooling duct 11 is needed, the opening and closing device 14 is opened to allow airflow in the cooling duct 11. Specifically, the opening and closing device 14 can be controlled by a control valve to achieve the desired opening degree and cooling flow rate.

[0032] As one embodiment, the airflow equalization device 5 includes longitudinal ribs 15 arranged along the axial direction of the air supply duct 1, such as... Figure 4 As shown, the structural design enhances heat exchange. Multiple longitudinal fins 15 are circumferentially distributed on the inner wall of the air supply duct 1 and parallel to the airflow direction. Specifically, the longitudinal fins 15 are made of Q235B steel strips, 2mm thick, 10mm high, and spaced 50mm apart. They are evenly distributed along the axial direction of the duct and parallel to the airflow direction. Their function is to increase the heat dissipation area of ​​the inner wall by 30%, shorten the heat conduction path, and ensure that the temperature gradient at the root of the fins is ≤5℃ / mm.

[0033] Furthermore, an airflow distribution cone 16 can be installed inside the air supply duct 1. The airflow distribution cone 16 is placed on the axis of the air supply duct 1, and the tip of the airflow distribution cone 16 points to the airflow inlet. The bottom diameter of the airflow distribution cone 16 should not be too large. If it is too large, it will affect the flow rate of the airflow in the air supply duct 1. In this embodiment, the airflow distribution cone 16 can guide the oncoming airflow to the inner wall surface of the air supply duct 1 through the cone. With the use of the longitudinal ribs 15, the airflow can better exchange heat with the surface of the air supply duct 1.

[0034] As another implementation, the airflow equalization device 5 includes turbulence protrusions 17 on the inner wall of the air supply duct 1, such as... Figure 5 As shown, the turbulence protrusion 17 is a hemispherical protrusion protruding from the inner wall of the air supply duct 1, and several turbulence protrusions 17 are evenly distributed at intervals on the inner wall of the air supply duct 1. Specifically, the diameter of the hemispherical protrusion is preferably set to 5-10 mm, the spacing is 30-50 mm, and it is distributed in an array to cover the entire circumference of the inner wall of the air supply duct. Its function is to disrupt the airflow boundary layer, so that the turbulence intensity increases from Re=10. 4 Increased to Re=1.5×10 4 The convective heat transfer coefficient is increased by 40%, thereby improving the heat exchange efficiency between the airflow and the air supply duct 1.

[0035] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A structure for an electromagnetic induction heating duct for a specially coated ship cabin, characterized in that, It includes an air supply pipe (1), an electromagnetic induction heating coil (2) is provided on the air supply pipe (1), the air supply pipe (1) is made of magnetic material, and the air supply pipe is placed in the module compartment (3). The module compartment (3) also includes a cooling system (4) for the air supply pipe (1) body; the inner wall of the air supply pipe (1) is provided with an airflow equalization device (5).

2. The electromagnetic induction heating duct structure for a ship's specially coated cabin according to claim 1, characterized in that, The cooling system (4) is a forced air cooling system, including a cooling fan (6) and a vent (7) installed on the side wall of the module compartment (3). The cooling fan (6) is a drive device for establishing forced airflow circulation in the module compartment (3).

3. The electromagnetic induction heating duct structure for a ship's specially coated cabin according to claim 1, characterized in that, The cooling system (4) is a built-in fluid cooling system (4), which includes a spiral cooling channel (8) provided inside or on the surface of the air duct (1), and a cooling medium flows in the spiral cooling channel (8).

4. The electromagnetic induction heating duct structure for a ship's specially coated cabin according to claim 3, characterized in that, The spiral cooling channel (8) is a fluid pipe made of non-magnetic material.

5. The electromagnetic induction heating duct structure for a ship's specially coated cabin according to claim 3 or 4, characterized in that, The spiral cooling channel (8) is wound in the same direction as the electromagnetic induction heating coil (2) on the air supply pipe (1), and the pitch matches the coil spacing.

6. The electromagnetic induction heating duct structure for a ship's specially coated cabin according to claim 1, characterized in that, The cooling system (4) includes a necked section (9) and an outer sleeve (10) provided on the air supply pipe (1). The outer sleeve (10) is coaxially sleeved on the cooling part of the air supply pipe (1), so that a cooling duct (11) is formed between the air supply pipe and the outer sleeve (10). One end of the cooling duct (11) is a closed end (12) and the other end is an open end (18). The closed end (12) is connected to the necked section (9) inside the air supply pipe (1).

7. The electromagnetic induction heating duct structure for a ship's specially coated cabin according to claim 6, characterized in that, A controllable opening and closing device (14) is provided at the connection between the closed end (12) of the outer sleeve (10) and the air supply pipe (1).

8. The electromagnetic induction heating duct structure for a ship's specially coated compartment according to claim 1, characterized in that, The airflow homogenization device (5) includes longitudinal ribs (15) arranged along the axial direction of the air supply pipe (1). Multiple longitudinal ribs (15) are circumferentially distributed on the inner wall of the air supply pipe (1) and parallel to the airflow direction.

9. The electromagnetic induction heating duct structure for a ship's specially coated compartment according to claim 8, characterized in that, The air supply pipe (1) has an airflow distribution cone (16) at its inlet end. The airflow distribution cone (16) is placed on the axis of the air supply pipe (1), and the tip of the airflow distribution cone (16) points to the airflow inlet end.

10. The electromagnetic induction heating duct structure for a ship's specially coated cabin according to claim 1, characterized in that, The airflow equalization device (5) includes a turbulence protrusion (17) provided on the inner wall of the air supply pipe (1). The turbulence protrusion (17) is a hemispherical protrusion protruding from the inner wall of the air supply pipe (1). Several turbulence protrusions (17) are evenly distributed on the inner wall of the air supply pipe (1).

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