Lightweight seawater heat exchanger and engine

Abstract

The present application relates to the technical field of engine cooling, and more particularly to a lightweight seawater heat exchanger and engine. The heat exchanger comprises a shell, a bushing structure and an anode rod. The shell comprises an end cover and a shell body, and the end cover and the shell body are connected by a connecting piece. The connecting piece and the shell body are made of conductive material, and the end cover is made of non-conductive material. The bushing structure is made of conductive material, is embedded in the end cover, and comprises an anode bushing, a connecting bushing and a conductive sheet. The conductive sheet connects the anode bushing and the connecting bushing. The anode rod is installed in the anode bushing, and the connecting piece is installed in the connecting bushing. The heat exchanger realizes weight reduction and cost reduction under the premise of ensuring corrosion resistance and structural reliability.

Description

Technical Field

[0001] This invention relates to the field of engine cooling technology, and more particularly to a lightweight seawater heat exchanger and engine. Background Technology

[0002] Seawater heat exchangers for marine engines transfer the heat generated during engine operation to seawater through heat exchange, ensuring the engine operates within a suitable temperature range. Seawater heat exchangers typically employ a shell-and-tube structure, consisting of an outer shell and an internal cooling core. The cooling medium (seawater) and the medium being cooled (engine coolant) exchange heat through flow channels within the shell. Due to the highly corrosive nature of seawater, components in the heat exchanger that come into contact with seawater must be made of corrosion-resistant materials, and sacrificial anode cathodic protection measures are often implemented to enhance the reliability of the equipment in complex marine environments.

[0003] A shell-and-tube seawater heat exchanger includes a shell, end caps, and a cooling core housed within the shell. Engine coolant flows within the shell, while seawater circulates in the end caps and the inner core channels. To resist seawater corrosion, components in contact with seawater, such as the end caps and cooling core, are mostly made of copper alloy. In addition, a removable zinc block is placed on the seawater side as a sacrificial anode, forming a galvanic cell through electrochemical principles: the zinc block is consumed as the anode, and the protected metal component is protected as the cathode, thereby delaying corrosion. The formation of a galvanic cell requires three conditions: (1) the electrode materials consist of two metals with different reactivity or other conductive materials; (2) an electrolyte is present; and (3) a wire connects the two electrodes, forming a closed circuit.

[0004] The extensive use of copper alloys results in a large overall weight and high manufacturing cost for heat exchangers, making them unsuitable for applications with stringent weight requirements, such as yachts. To reduce weight, some solutions replace the end caps with non-metallic materials like engineering plastics. However, since plastics are non-conductive, they cannot meet the circuit conditions for a galvanic cell, preventing the zinc anode from providing cathodic protection to the cooling core. Upgrading the cooling core material to a higher corrosion-resistant alloy would significantly increase costs. Furthermore, using external wires to connect the zinc anode and cooling core exposes the wires to the environment, making them prone to corrosion and breakage. This not only reduces reliability but also affects the overall aesthetics and ease of maintenance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a lightweight seawater heat exchanger. By setting a conductive bushing structure embedded in the end cap, an effective electrical connection is formed between the zinc anode and the cooling core. This allows the use of lightweight non-metallic end caps while maintaining the sacrificial anode cathodic protection function, achieving weight reduction and cost reduction while ensuring corrosion resistance and structural reliability.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: A lightweight seawater heat exchanger includes: a shell, a bushing structure, and an anode rod; the shell includes an end cap and a housing, which are connected by a connector, wherein the connector and the housing are made of conductive material, and the end cap is made of non-conductive material; the bushing structure is made of conductive material and is embedded in the end cap, including an anode bushing, a connecting bushing, and a conductive plate, the conductive plate connecting the anode bushing and the connecting bushing, the anode rod being installed in the anode bushing, and the connector being installed in the connecting bushing.

[0007] Optionally, the axis of the connecting bushing is perpendicular to the end face of the end cap, and the axis of the anode bushing is perpendicular to the axis of the connecting bushing.

[0008] Optionally, the end cap is made of plastic, and the bushing structure is embedded in the end cap.

[0009] Optionally, the connector is a bolt, and the end face of the housing is provided with a threaded hole. The bolt passes through the connecting bushing and is installed in the threaded hole of the housing.

[0010] Optionally, the heat exchanger further includes a cooling core installed inside the housing. The cooling core includes end plates and cooling water pipes. The end plates are disposed at both ends of the cooling water pipes and separate the end cover cavity from the housing cavity.

[0011] Optionally, the inner cavity of the end cap and the cooling water pipe form a cooling medium flow channel, and the cavity between the cooling water pipe and the shell forms a flow channel for the cooled medium.

[0012] Optionally, the heat exchanger further includes a sealing ring, which is installed at the mating point between the end plate and the end cover and the housing.

[0013] Optionally, the outer ring of the end plate is provided with a flange plate, and the end of the end cover and the housing facing the flange plate are both provided with an annular groove, and the sealing ring is installed in the annular groove.

[0014] Optionally, the cooling core may further include a baffle plate disposed on the wall of the cooling water pipe.

[0015] This invention also provides an engine, including the lightweight seawater heat exchanger described above.

[0016] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: 1. The lightweight seawater heat exchanger of the present invention includes a shell, a bushing structure, and an anode rod. The shell is composed of an end cap and a housing connected by a connector, wherein the connector and the housing are made of conductive material, and the end cap is made of non-conductive material. The bushing structure is made of conductive material and embedded in the end cap, and includes an anode bushing, a connecting bushing, and a conductive plate. The conductive plate connects the anode bushing and the connecting bushing. The anode rod is installed inside the anode bushing, and the connector is installed inside the connecting bushing. This structure forms a conductive path within the non-conductive end cap through the bushing, allowing the anode rod to establish an electrical connection with the cooling core through the bushing structure, the connector, the shell, and thus satisfying the galvanic cell circuit conditions for sacrificial anode cathodic protection. This solves the problem of not being able to form an electrochemical protection circuit when using lightweight non-metallic end caps, avoids increased costs due to upgrading the cooling core material, and maintains the reliability of corrosion protection. The bushing structure ensures that the current is conducted from the anode rod through the anode bushing, conductive sheet, connecting bushing, and connector to the housing, and then to the cooling core, forming a complete closed loop. This allows the sacrificial anode cathodic protection function to be maintained while using lightweight non-metallic end caps, achieving weight reduction and cost reduction while ensuring corrosion resistance and structural reliability.

[0017] 2. The bushing structure of this invention, by embedding the bushing structure (anode bushing, connecting bushing, and conductive sheet) into the plastic end cap, forms an internal conductive path, completely solving the reliability problem caused by the easy corrosion and breakage of external wires. Compared with traditional wire solutions, the bushing structure and end cap are integrally molded, which not only avoids the wires being exposed to the harsh marine environment, but also enhances the overall structure and stability, preventing connection failure due to vibration or impact. Combining the lightweight advantages of the plastic end cap, this design significantly reduces the weight of the heat exchanger and lowers material costs while ensuring the continued effectiveness of the sacrificial anode protection circuit without the need to upgrade the cooling core material. In addition, wire connections require drilling for wiring, which can easily damage the seal integrity, increase the risk of leakage, and affect the structural aesthetics. The bushing structure and end cap are integrally molded, eliminating the need for additional openings, ensuring media sealing, and simplifying assembly and maintenance. The synergistic optimization of lightweight and corrosion resistance in this invention breaks through the bottleneck of non-metallic end caps in seawater heat exchangers, improving the overall durability and adaptability of the equipment.

[0018] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation thereof. Furthermore, the spacing or dimensions between components are exaggerated to show their positions; the schematic diagrams are for illustrative purposes only.

[0020] Figure 1This is an overall schematic diagram of the heat exchanger provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the bushing structure provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the bushing structure provided in an embodiment of the present invention installed inside the end cap; Figure 4 This is a schematic diagram of the anode rod installed in the anode bushing according to an embodiment of the present invention; In the diagram: 1. Front end cover; 2. Sealing ring; 3. Cooling core; 3.1. End plate; 3.2. Cooling water pipe; 3.3. Baffle plate; 4. Housing; 5. Rear end cover; 6. Zinc anode; 7. Bolt; 8. Bushing structure; 8.1. Anode bushing; 8.2. Conductive sheet; 8.3. Connecting bushing; Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0021] Terminology Explanation: Heat exchanger: also known as a heat exchanger, is a device that transfers part of the heat from a hot fluid to a cold fluid.

[0022] Electrochemical corrosion: Electrochemical corrosion occurs when a metal and an electrolyte form a galvanic cell, acting as two electrodes. A galvanic cell is a device that generates current through a redox reaction; it can also be described as a device that converts chemical energy into electrical energy. Negative electrode: the electrode from which electrons flow out; Positive electrode: the electrode into which electrons flow in; Anode: the electrode where the oxidation reaction occurs; Cathode: the electrode where the reduction reaction occurs. In a galvanic cell, the external circuit conducts electricity electronically, while the electrolyte solution conducts electricity ionicly.

[0023] Zinc anode: An electrode that provides protection to the coupled cathode by increasing its own corrosion rate.

[0024] Sacrificial anode cathodic protection involves connecting a metal with a more negative potential to the metal being protected, placing them in the same electrolyte. This causes electrons to transfer from the sacrificial anode metal to the protected metal, bringing the entire protected metal to a similarly negative potential. Sacrificial anode cathodic protection is one of the earliest electrochemical protection techniques.

[0025] like Figure 1 , Figure 2 , Figure 3 , Figure 4As shown, this embodiment proposes a lightweight seawater heat exchanger, including: a shell, a bushing structure 8, and an anode rod; the shell includes an end cap (divided into a front end cap 1 and a rear end cap 5) and a housing 4, the end cap and the housing 4 are connected by a connector, wherein the connector and the housing 4 are made of conductive material, and the end cap is made of non-conductive material; the bushing structure 8 is made of conductive material and is embedded in the end cap, including an anode bushing 8.1, a connecting bushing 8.3, and a conductive plate 8.2, the conductive plate 8.2 connecting the anode bushing 8.1 and the connecting bushing 8.3, the anode rod being installed in the anode bushing 8.1, and the connector being installed in the connecting bushing 8.3.

[0026] The housing 4 can be made of die-cast aluminum, and the connecting parts can be metal bolts 7, both of which have good conductivity. The end caps can be made of non-conductive materials such as high-strength engineering plastics, such as PPS with glass fiber, which has strong corrosion resistance and does not require zinc anodes 6 for protection. The anode bushing 8.1, connecting bushing 8.3, and conductive plate 8.2 in the bushing structure 8 can all be made of conductive materials such as copper alloy. The anode bushing 8.1 and connecting bushing 8.3 are connected as one piece by the conductive plate 8.2 using a welding process.

[0027] Non-conductive end caps significantly reduce the weight of the heat exchanger. Compared to traditional copper alloy end caps, plastic end caps have a lower density, effectively reducing the overall weight of the heat exchanger. Furthermore, the plastic material is corrosion-resistant, eliminating the need for additional anti-corrosion treatment and reducing material costs. The bushing structure 8 solves the problem of the cooling core 3 being unable to pass sacrificial anode protection due to the non-conductivity of the plastic end caps. With the anode rod acting as the anode, the cooling core 3 as the cathode, and seawater as the electrolyte, current can be transferred through the anode rod to the anode bushing 8.1, then through the conductive sheet 8.2 to the connecting bushing 8.3, and finally through the conductive connector to the conductive shell 4. The shell 4 contacts the cooling core 3, ultimately transferring current to the cooling core 3, forming a complete closed-loop galvanic cell. This satisfies the conditions for sacrificial anode cathodic protection, effectively preventing corrosion of the cooling core 3 without requiring an upgrade to a more corrosion-resistant alloy material, thus controlling costs.

[0028] like Figure 2 , Figure 3 As shown, the axis of the connecting bushing 8.3 is perpendicular to the end face of the end cap, and the axis of the anode bushing 8.1 is perpendicular to the axis of the connecting bushing 8.3.

[0029] The connector is usually installed along the axial direction of the end cap. Therefore, the axis of the connecting bushing 8.3 is perpendicular to the end face of the end cap, which can ensure that the connector passes smoothly through the connecting bushing 8.3 and is reliably connected to the housing 4. The anode bushing 8.1 needs to be fitted with an anode rod, the axis of which is perpendicular to the axis of the connecting bushing 8.3. This avoids the two occupying space in the end cap and ensures that the anode rod is in full contact with seawater after installation. This ensures that the electrolyte can effectively wrap the anode rod during sacrificial anode protection without affecting the galvanic cell reaction efficiency.

[0030] The plastic end cap has a much lower density than traditional copper alloys, significantly reducing its weight and consequently the overall weight of the heat exchanger. Furthermore, the plastic material offers excellent resistance to seawater corrosion, eliminating the need for zinc anodes (6) for corrosion protection and reducing the number of corrosion-resistant components. The bushing structure 8 is embedded in the end cap using a casting method. This process ensures a secure bond between the bushing structure 8 and the plastic end cap, preventing it from loosening or detaching under seawater pressure or vibration. This guarantees the positional stability of the bushing structure 8 and ensures reliable conductivity. Additionally, the casting method allows the bushing structure 8 to be fully embedded within the end cap, extending its service life and preventing it from protruding and affecting the overall appearance and installation space of the heat exchanger.

[0031] The connecting component is a bolt 7. A threaded hole is provided on the end face of the housing 4. The bolt 7 passes through the connecting bushing 8.3 and is installed in the threaded hole of the housing 4. The bolt 7 connection ensures a tight connection between the end cover and the housing 4, preventing gaps between the end cover and the housing 4 that could lead to media leakage. It also facilitates subsequent maintenance and replacement of internal components of the heat exchanger.

[0032] like Figure 1 As shown, the heat exchanger also includes a cooling core 3 installed inside the outer shell. The cooling core 3 includes end plates 3.1 and cooling water pipes 3.2. The end plates 3.1 are located at both ends of the cooling water pipes 3.2, and the end plates 3.1 separate the inner cavity of the end cover and the inner cavity of the shell 4. The end plates 3.1 in the cooling core 3 can be made of brass or zinc-copper alloy, etc., and the cooling water pipes 3.2 can be made of copper-nickel alloy. The cooling water pipes 3.2 and the end plates 3.1 can be connected by tube expansion or brazing.

[0033] Cooling water pipe 3.2 is the main channel for heat exchange. Hot and cold fluids flow inside and outside the cooling water pipe 3.2 respectively, transferring heat through the pipe wall. End plate 3.1 fixes the cooling water pipe 3.2, ensuring its structural stability and thus guaranteeing the stability of the heat exchange area. The design of end plate 3.1 separating the end cover cavity from the shell cavity 4 separates the two media into different spaces, preventing media mixing.

[0034] The inner cavity of the end cap and the cooling water pipe 3.2 form a cooling medium flow channel, and the cavity between the cooling water pipe 3.2 and the shell 4 forms a flow channel for the cooled medium.

[0035] The cooling medium is seawater, and the medium being cooled is engine coolant. Seawater enters the coolant pipe 3.2 from the inner cavity of the end cap. During its flow within the coolant pipe 3.2, it exchanges heat with the engine coolant outside the coolant pipe 3.2. After absorbing heat, the seawater flows out from the end cap at the other end, while the cooled engine coolant flows out of the heat exchanger.

[0036] The heat exchanger also includes a sealing ring 2, which is installed at the mating point between the end plate 3.1 and the end cover / shell 4. The sealing ring 2 fills the tiny gaps at the mating point, achieving a seal through its elastic deformation to prevent media leakage. The sealing ring 2 can be made of rubber, which has good elasticity and seawater corrosion resistance, maintaining its sealing performance for a long time in seawater environments, eliminating the need for frequent replacements and reducing maintenance costs.

[0037] The outer ring of the end plate 3.1 is provided with a flange plate, and the end of the end cover and the housing 4 facing the flange plate are both provided with annular grooves, and the sealing ring 2 is installed in the annular groove. The cooperation between the flange plate and the annular groove makes it easier to position the sealing ring 2 during installation, simplifies the assembly process, and improves the convenience of heat exchanger assembly and maintenance.

[0038] The cooling core 3 also includes a baffle plate 3.3, which is disposed on the wall of the cooling water pipe 3.2. When the cooling medium flows in the cooling water pipe 3.2, the baffle plate 3.3 can disrupt the flow state of the medium, transforming laminar flow into turbulent flow, destroying the laminar boundary layer, allowing the medium to have more sufficient contact with the inner wall of the water pipe, accelerating the heat transfer rate, and thus improving the heat exchange efficiency of the entire heat exchanger.

[0039] Based on the aforementioned lightweight seawater heat exchanger, this embodiment also provides an engine. The lightweight seawater heat exchanger uses plastic end caps and a die-cast aluminum shell 4, and its weight is much lower than that of traditional copper alloy heat exchangers. This can effectively reduce the overall weight of the engine, improve the engine's maneuverability, meet the stringent weight requirements of marine engines, and maintain a suitable operating temperature in different sea environments, thus expanding the engine's applicability.

[0040] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A lightweight seawater heat exchanger, characterized in that, include: The outer casing, bushing structure (8), and anode rod; The outer casing includes an end cap and a housing (4), which are connected by a connector. The connector and the housing (4) are made of conductive material, and the end cap is made of non-conductive material. The bushing structure (8) is made of conductive material and is embedded in the end cap. It includes an anode bushing (8.1), a connecting bushing (8.3), and a conductive sheet (8.2). The conductive sheet (8.2) connects the anode bushing (8.1) and the connecting bushing (8.3). The anode rod is installed in the anode bushing (8.1), and the connector is installed in the connecting bushing (8.3).

2. The lightweight seawater heat exchanger as described in claim 1, characterized in that, The axis of the connecting bushing (8.3) is perpendicular to the end face of the end cap, and the axis of the anode bushing (8.1) is perpendicular to the axis of the connecting bushing (8.3).

3. The lightweight seawater heat exchanger as described in claim 1, characterized in that, The end cap is made of plastic material, and the bushing structure (8) is embedded in the end cap.

4. The lightweight seawater heat exchanger as described in claim 1, characterized in that, The connector is a bolt (7), and the end face of the housing (4) is provided with a threaded hole. The bolt (7) passes through the connecting bushing (8.3) and is installed in the threaded hole of the housing (4).

5. The lightweight seawater heat exchanger as described in claim 1, characterized in that, The heat exchanger also includes a cooling core (3) installed inside the outer shell. The cooling core (3) includes an end plate (3.1) and a cooling water pipe (3.2). The end plate (3.1) is disposed at both ends of the cooling water pipe (3.2) and the end plate (3.1) separates the inner cavity of the end cover from the inner cavity of the shell (4).

6. The lightweight seawater heat exchanger as described in claim 5, characterized in that, The inner cavity of the end cap and the cooling water pipe (3.2) form a cooling medium flow channel, and the cavity between the cooling water pipe (3.2) and the shell (4) forms a flow channel for the cooled medium.

7. The lightweight seawater heat exchanger as described in claim 5, characterized in that, The heat exchanger also includes a sealing ring (2), which is installed at the mating point between the end plate (3.1) and the end cover and the shell (4).

8. The lightweight seawater heat exchanger as described in claim 7, characterized in that, The outer ring of the end plate (3.1) is provided with a flange plate, and the end cap and the housing (4) are both provided with an annular groove at the end facing the flange plate. The sealing ring (2) is installed in the annular groove.

9. The lightweight seawater heat exchanger as described in claim 5, characterized in that, The cooling core (3) also includes a baffle (3.3), which is disposed on the wall of the cooling water pipe (3.2).

10. An engine, characterized in that, Including the lightweight seawater heat exchanger as described in any one of claims 1-9.

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