PTC heating device

Abstract

The utility model provides a PTC (Positive Temperature Coefficient) heating device, which belongs to the technical field of diesel oil heating, and comprises a shell, a sealing element, a PTC heating element, a conductive module and an insulating sleeve, the shell is provided with a heating cavity and a mounting port for communicating the heating cavity to the outside; the sealing piece covers the mounting opening in a sealing manner; the PTC heating piece is arranged in the heating cavity and is used for generating heat energy; the conductive module comprises a positive electrode and a negative electrode which are arranged on the two opposite sides of the PTC heating piece, and the positive electrode and the negative electrode are electrically connected with the PTC heating piece; the conductive module is arranged in the shell, the insulating sleeve is wrapped outside the conductive module, the insulating sleeve comprises a heat-conducting silica gel layer and a polyimide layer, the heat-conducting silica gel layer is attached to the exterior of the conductive module, the polyimide layer is wrapped outside the heat-conducting silica gel layer, and the polyimide layer is attached to the inner wall of the shell. The utility model provides a PTC (Positive Temperature Coefficient) heating device and aims to solve the problems that in the prior art, a polyimide film is used as an insulating layer, so that the heat transfer efficiency is low, a heating state needs to be continuously maintained, and the energy consumption is increased.

Description

Technical Field

[0001] This utility model belongs to the field of diesel heating technology, and more specifically, it relates to a PTC heating device. Background Technology

[0002] Among everyday fuels, diesel has the highest energy density, nearly twice that of liquefied natural gas and more than 10% higher than that of gasoline. Diesel engines use compression ignition, eliminating the need for spark plugs. Furthermore, the fuel supply system of diesel engines is relatively simple, resulting in better reliability than gasoline engines. Heavy vehicles and construction machinery use diesel engines; however, diesel fuel is prone to becoming cloudy in low-temperature environments, leading to poor fuel flow and causing wax buildup and icing in fuel filters, thus affecting the normal fuel supply to the system.

[0003] To ensure the normal operation of the fuel system in low-temperature environments, PTC heaters are typically installed inside the fuel filter to maintain diesel fuel flow. PTC heaters are usually wrapped with a polyimide membrane as the insulation layer. While polyimide membranes have good high-temperature and corrosion resistance, their low thermal conductivity means that the heat generated by the heater cannot be quickly and fully transferred to the diesel fuel. This causes heat to accumulate on the surface of the heater, and the thermistor characteristics of the PTC heater cause its resistance to increase and its current to decrease. Over time, this reduces the stable power of the heater, deteriorates the heating effect, and requires maintaining the heating state for an extended period to circulate diesel fuel, resulting in energy waste. Utility Model Content

[0004] The purpose of this invention is to provide a PTC heating device that addresses the problem in the prior art where polyimide film is used as an insulating layer, resulting in low heat transfer efficiency, the need to continuously maintain the heating state, and increased energy consumption.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A PTC heating device is provided, comprising:

[0007] The outer casing has a heating chamber and a mounting port that connects the heating chamber to the outside;

[0008] A sealing element is used to seal the mounting port;

[0009] A PTC heating element is disposed inside the heating cavity to generate heat energy;

[0010] A conductive module, comprising a positive electrode and a negative electrode disposed on opposite sides of the PTC heating element, wherein the positive electrode and the negative electrode are electrically connected to the PTC heating element, respectively; and

[0011] An insulating sleeve is wrapped around the conductive module. The insulating sleeve includes a thermally conductive silicone layer that adheres to the outside of the conductive module and a polyimide layer that wraps around the thermally conductive silicone layer. The polyimide layer adheres to the inner wall of the outer shell.

[0012] In one possible implementation, the seal has a sealing portion inserted into the heating chamber.

[0013] In one possible implementation, the seal includes:

[0014] A mounting cover is inserted into the outer casing, and the mounting cover has a clearance channel; and

[0015] A sealing plug is inserted into the clearance channel, and the end of the sealing plug is inserted into the heating chamber to form the sealing part.

[0016] In one possible implementation, the sealing plug includes a limiting body and a sealing body connected in sequence. The cross-section of the limiting body is larger than the cross-section of the sealing body, and the sealing body is inserted into the heating cavity to form the sealing part. The limiting body is inserted into the clearance channel and abuts against the end face of the outer shell.

[0017] In one possible implementation, a locking block is provided on the outer side of the housing, and the sealing element is fitted onto the outer side of the housing and engages with the locking block.

[0018] In one possible implementation, both the positive electrode and the negative electrode include a conductive portion and a connecting portion connected to the conductive portion. The conductive portion is attached to the outside of the PTC heating element and is electrically connected to the PTC heating element. The cross-section of the connecting portion is smaller than the cross-section of the conductive portion and extends through the seal out of the heating cavity.

[0019] In one possible implementation, the heating cavity includes a receiving area, a transition area, and an installation area distributed sequentially. The cross-section of the receiving area is rectangular, the PTC heating element is disposed within the receiving area, and the cross-section of the installation area is larger than the cross-section of the receiving area.

[0020] In one possible implementation, the seal is inserted into the mounting area.

[0021] In one possible implementation, the housing has a limiting boss located in the mounting area, and the seal is inserted into the mounting area and abuts against the limiting boss.

[0022] In one possible implementation, the top of the insulating sleeve has a clearance opening through which the conductive module passes.

[0023] The beneficial effects of the PTC heating device provided by this utility model are as follows: Compared with the prior art, the PTC heating device of this utility model places the positive electrode and the negative electrode on opposite sides of the PTC heating element and electrically connects them to the PTC heating element. The positive electrode and the negative electrode are electrically connected to an external power source to power the PTC heating element. The sealing component encloses the heating cavity to prevent external oil or other substances from entering the heating cavity and affecting the service life of the PTC heating element. An insulating sleeve is wrapped around the conductive module formed by the positive and negative electrodes. Since the insulating sleeve includes a polyimide layer and a thermally conductive silicone layer, the polyimide layer has good insulation properties, while the thermally conductive silicone layer has good insulation and elastic deformation capabilities. After the insulating sleeve is filled into the heating cavity, the thermally conductive silicone layer is compressed and deformed, thus making close contact with the outer shell and preventing air from remaining between the thermally conductive silicone layer and the outer shell. Air is a poor conductor of heat, and venting the air facilitates the rapid and sufficient transfer of heat to the outside. This invention uses a composite of polyimide and thermally conductive silicone as an insulating sleeve, which not only achieves insulation but also allows the heat generated by the PTC heating element to be quickly dissipated, preventing heat accumulation on the outside of the PTC heating element that could increase its resistance and reduce its stable power. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of the structure of the PTC heating device provided in the embodiment of this utility model;

[0026] Figure 2 A schematic diagram of the structure of a PTC heating device provided in another embodiment of this utility model;

[0027] Figure 3 Another structural schematic diagram of the PTC heating device provided in this embodiment of the utility model;

[0028] Figure 4 A cross-sectional view of the PTC heating device provided in an embodiment of this utility model;

[0029] Figure 5 for Figure 4 Enlarged view of part A in the middle;

[0030] Figure 6 This is a schematic diagram of the structure of the PTC heating element and conductive module used in the embodiments of this utility model;

[0031] Figure 7This is a schematic diagram of the sealing plug used in an embodiment of the present invention.

[0032] In the diagram: 1. Outer shell; 101. Receiving area; 102. Transition area; 103. Mounting area; 104. Locking block; 2. Seal; 201. Mounting cover; 202. Sealing plug; 2021. Limiting body; 2022. Sealing body; 3. Conductive module; 301. Positive electrode; 302. Negative electrode; 3021. Conductive part; 3022. Connecting part; 4. Wire; 5. PTC heating element; 6. Insulating sleeve; 601. Thermally conductive silicone layer; 602. Polyimide layer. Detailed Implementation

[0033] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0034] In the claims, description, and accompanying drawings of this utility model, unless otherwise expressly defined, the terms "first," "second," or "third," etc., are used to distinguish different objects, not to describe a specific order. Unless otherwise stated, other directional terms, such as "vertical," "clockwise," and "counterclockwise," indicate orientation or positional relationships based on the orientation and positional relationships shown in the accompanying drawings, and are only for the convenience of describing the utility model and simplifying the description, not to indicate or imply that the referred device or element must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the specific scope of protection of this utility model. In the claims, description, and accompanying drawings of this utility model, unless otherwise expressly defined, the terms "fixed connection" or "fixed connection" should be interpreted broadly, that is, any connection method in which there is no displacement relationship or relative rotation relationship between the two, that is, including non-removable fixed connection, detachable fixed connection, integral connection, and fixed connection through other devices or elements. In the claims, description, and accompanying drawings of this utility model, the terms "comprising," "having," and their variations are intended to mean "including but not limited to."

[0035] Please refer to the following: Figures 1 to 6The PTC heating device provided by this utility model will now be described. The PTC heating device includes a shell 1, a sealing element 2, a PTC heating element 5, a conductive module 3, and an insulating sleeve 6. The shell 1 has a heating cavity and an installation port that connects the heating cavity to the outside. The sealing element 2 covers the installation port. The PTC heating element 5 is disposed in the heating cavity and is used to generate heat energy. The conductive module 3 includes a positive electrode 301 and a negative electrode 302 disposed on opposite sides of the PTC heating element 5. The positive electrode 301 and the negative electrode 302 are electrically connected to the PTC heating element 5, respectively. The insulating sleeve 6 is wrapped around the conductive module 3. The insulating sleeve 6 includes a thermally conductive silicone layer 601 attached to the outside of the conductive module 3 and a polyimide layer 602 wrapped around the thermally conductive silicone layer 601. The polyimide layer 602 is attached to the inner wall of the shell 1.

[0036] Compared with the prior art, the PTC heating device provided by this utility model has a positive electrode 301 and a negative electrode 302 respectively disposed on opposite sides of the PTC heating element 5 and electrically connected to the PTC heating element 5. The positive electrode 301 and the negative electrode 302 are electrically connected to an external power source to supply power to the PTC heating element 5. The sealing element 2 seals the heating cavity to prevent external oil or other substances from entering the heating cavity and affecting the service life of the PTC heating element 5. An insulating sleeve 6 is wrapped around the conductive module 3 formed by the positive electrode 301 and the negative electrode 302. Since the insulating sleeve 6 includes a polyimide layer 602 and a thermally conductive silicone layer 601, the polyimide layer 602 has good insulation properties, while the thermally conductive silicone layer 601 has good insulation and elastic deformation ability. After the insulating sleeve 6 is filled into the heating cavity, the thermally conductive silicone layer 601 is squeezed and deformed, thereby making the polyimide layer 602 in close contact with the outer shell 1, preventing air from remaining between the polyimide layer 602 and the outer shell 1. Air is a poor conductor of heat, and expelling the air facilitates rapid and sufficient heat transfer to the outside. This invention uses a composite of polyimide and thermally conductive silicone layer 601 as an insulating sleeve 6, which achieves both insulation and rapid heat transfer from the PTC heating element 5, preventing heat accumulation on the outside of the PTC heating element 5 that could increase its resistance and reduce its stable power.

[0037] It should be noted that the insulating sleeve 6 in the prior art is formed by 2-3 layers of polyimide 602 composite. The thickness of a single polyimide 602 layer is only 0.05mm, which not only fails to meet the insulation requirements, but also makes it prone to breakage due to its small thickness. Therefore, multiple layers of polyimide 602 composite are required to meet the insulation requirements. However, due to the low thermal conductivity of polyimide 602, the thermal conductivity of the insulating sleeve 6 formed by multiple layers of polyimide 602 composite is further reduced, which is not conducive to the outward transfer of heat generated by the PTC heating element 5. In contrast, the insulating sleeve 6 in this application is formed by a single layer of polyimide 602 composite and a thermally conductive silicone layer 601 composite. The single layer of polyimide 602 can provide insulation, while the thermally conductive silicone layer 601 has good thermal conductivity and insulation properties. Under the premise of ensuring sufficient thickness and reducing the probability of damage, the heat generated by the PTC heating element 5 can be quickly transferred outward.

[0038] It should be noted that the thermally conductive silicone layer 601 in this invention contains metal oxide particles, which further improves the thermal conductivity. Of course, since the polyimide already encapsulates the conductive module 3, providing insulation, the metal oxide content should be added appropriately while ensuring the insulation effect to further guarantee the insulation performance.

[0039] It should be noted that, since the thermally conductive silicone layer 601 is a flexible component, it is easily damaged under stress. Therefore, the thermally conductive silicone layer 601 is placed inside the polyimide layer 602. This prevents the thermally conductive silicone layer 601 from being damaged by friction when the insulating sleeve 6 is placed into the heating cavity. Furthermore, during installation, the polyimide layer 602 compresses the thermally conductive silicone layer 601, allowing the entire module to enter the heating cavity. After installation, the thermally conductive silicone layer 601 recovers its elastic deformation, thereby ensuring tight contact between the polyimide layer 602 and the inner wall of the outer shell 1.

[0040] Optionally, the positive electrode 301 and the negative electrode 302 are respectively connected to wires 4.

[0041] Optionally, the PTC heating element 5 includes multiple PTC heating elements connected in parallel.

[0042] In some embodiments, please refer to Figure 1 The sealing element 2 has a sealing part inserted into the heating chamber.

[0043] The sealing part of the seal 2 is inserted into the heating chamber. Compared with the scheme of simply covering the installation port with the seal 2, the contact area with the outer shell 1 is increased, which further improves the sealing performance in the heating chamber.

[0044] Optionally, the sealing part abuts against the conductive module 3, which not only limits the sealing element 2, but also improves the positional stability of the conductive module 3 in the heating cavity, while reducing the air content in the heating cavity and improving the heat conduction effect.

[0045] In some embodiments, please refer to Figures 1 to 2 The sealing element 2 includes a mounting cover 201 and a sealing plug 202. The mounting cover 201 is inserted into the outer shell 1 and has a clearance channel. The sealing plug 202 is inserted into the clearance channel and its end is inserted into the heating chamber to form a sealing part.

[0046] In this embodiment, the mounting cover 201 and the sealing plug 202 adopt a separate structure, thus allowing the use of different materials. The sealing part of the sealing plug 202 is inserted into the heating chamber to achieve a seal. The clearance channel of the mounting cover 201 is fitted over the sealing plug 202 and connected to the outer shell 1. Because the mounting cover 201 needs to be fixed to the outer shell 1, it is made of a rigid material, such as metal or plastic, while the sealing plug 202 can be made of a flexible material with good elastic deformation ability, which can improve the sealing performance.

[0047] Optionally, the sealing plug 202 is interference-fitted with the clearance channel to improve sealing performance.

[0048] Optionally, the sealing plug 202 can be an elastic or flexible component, such as a rubber component or a silicone component.

[0049] Optionally, any cross-section of the sealing plug 202 can be adapted to the heating chamber, with one end inserted into the heating chamber and the other end inserted into the relief channel, that is, the relief channel is consistent with the cross-section of the heating chamber.

[0050] In some embodiments, please refer to Figure 7 The sealing plug 202 includes a limiting body 2021 and a sealing body 2022 connected in sequence. The cross-section of the limiting body 2021 is larger than the cross-section of the sealing body 2022, and the sealing body 2022 is inserted into the heating chamber to form a sealing part. The limiting body 2021 is inserted into the clearance channel and abuts against the end face of the outer shell 1.

[0051] The sealing body 2022 is inserted into the heating chamber, thereby sealing the heating chamber. The cross-section of the limiting body 2021 is larger than that of the sealing body 2022, so the limiting body 2021 abuts against the end face of the outer shell 1, thereby limiting the sealing plug 202. The solution in this embodiment ensures the stability and reliability of the position of the sealing plug 202, and prevents the sealing plug 202 from entering the heating chamber as a whole under force.

[0052] In some embodiments, please refer to Figure 3 The outer side of the outer shell 1 is provided with a locking block 104, and the sealing element 2 is sleeved on the outer shell 1 and engages with the locking block 104.

[0053] This embodiment uses a snap-fit ​​connection between the seal 2 and the locking block 104 to fix the seal 2, eliminating the need for the external connecting part 3022 and simplifying the assembly and disassembly process. Furthermore, compared to a screw connection, the snap-fit ​​method is not only easier to manufacture, but also avoids the problem of oil flow causing the seal 2 to rotate under stress, thus preventing loosening of the connection with the outer casing 1.

[0054] In some embodiments, please refer to Figure 6 Both the positive electrode 301 and the negative electrode 302 include a conductive part 3021 and a connecting part 3022 connected to the conductive part 3021. The conductive part 3021 is attached to the outside of the PTC heating element 5 and is electrically connected to the PTC heating element 5. The cross-section of the connecting part 3022 is smaller than the cross-section of the conductive part 3021 and extends out of the heating chamber through the sealing member 2.

[0055] The connecting portion 3022 extends out of the heating chamber after passing through the seal 2, and then connects to the wire 4. Since the cross-section of the connecting portion 3022 is smaller than the cross-section of the conductive portion 3021, the opening area on the seal 2 can be reduced, improving the sealing effect. Furthermore, in this embodiment, extending the connecting portion 3022 out of the seal 2 to connect to the wire 4, compared to inserting the wire 4 into the heating chamber and making a conductive connection with the connecting portion 3022, makes maintenance easier after the connection becomes loose, and avoids the problem of the connection becoming loose or failing due to the wire 4 being pulled during the installation of the seal 2.

[0056] In some embodiments, please refer to Figure 1 The heating chamber includes a receiving area 101, a transition area 102 and an installation area 103 arranged in sequence. The cross-section of the receiving area 101 is rectangular. The PTC heating element 5 is disposed in the receiving area 101. The cross-section of the installation area 103 is larger than the cross-section of the receiving area 101.

[0057] Since the PTC heating element 5 has a sheet or plate-like structure, the positive electrode 301 and negative electrode 302 are attached to both sides of the PTC heating element 5 to form a rectangular module. The rectangular module is then wrapped with an insulating sleeve 6, resulting in an inconvenient shape. The rectangular cross-section of the receiving area 101 allows for better fit with the insulating sleeve 6, increasing the contact area and facilitating the transfer of heat from the PTC heating element 5. The larger cross-sectional area of ​​the mounting area 103 allows for the formation of a convex boss structure, facilitating the fixation of the outer shell 1. The transition area 102 ensures a smooth transition between the receiving area 101 and the mounting area 103, avoiding localized stress concentration.

[0058] Specifically, the heating cavity connects the receiving area 101, the transition area 102, and the installation area 103.

[0059] In some embodiments, please refer to Figure 1 The sealing element 2 is inserted into the installation area 103.

[0060] In this embodiment, the seal 2 is inserted into the installation area 103. Compared with the solution where the seal 2 is sleeved on the outside of the outer shell 1, the exposed area of ​​the seal 2 is reduced, which reduces the probability of movement under force and improves the connection reliability with the outer shell 1.

[0061] Optionally, the seal 2 has external threads and the mounting area 103 has internal threads, and the seal 2 and the mounting area 103 are connected and fixed by screwing.

[0062] In some embodiments, please refer to Figure 4 The outer casing 1 has a limiting boss located in the mounting area 103, and the sealing member 2 is inserted into the mounting area 103 and abuts against the limiting boss.

[0063] After the seal 2 is inserted into the installation area 103, it abuts against the limiting boss, thereby limiting the seal 2 in the insertion direction and preventing the seal 2 from entering the heating chamber as a whole.

[0064] In some embodiments, please refer to Figure 4 The top of the insulating sleeve 6 has a clearance opening through which the conductive module 3 passes.

[0065] After passing through the clearance opening, the conductive module 3 (positive electrode 301 and negative electrode 302) is connected to an external power source via wire 4.

[0066] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A PTC heating device, characterized in that, include: The outer casing has a heating chamber and a mounting port that connects the heating chamber to the outside; A sealing element is used to seal the mounting port; A PTC heating element is disposed inside the heating cavity to generate heat energy; A conductive module, comprising a positive electrode and a negative electrode disposed on opposite sides of the PTC heating element, wherein the positive electrode and the negative electrode are electrically connected to the PTC heating element, respectively; and An insulating sleeve is wrapped around the conductive module. The insulating sleeve includes a thermally conductive silicone layer that adheres to the outside of the conductive module and a polyimide layer that wraps around the thermally conductive silicone layer. The polyimide layer adheres to the inner wall of the outer shell.

2. The PTC heating device as described in claim 1, characterized in that, The sealing element has a sealing portion inserted into the heating chamber.

3. The PTC heating device as described in claim 2, characterized in that, The sealing element includes: A mounting cover is inserted into the outer casing, and the mounting cover has a clearance channel; and A sealing plug is inserted into the clearance channel, and the end of the sealing plug is inserted into the heating chamber to form the sealing part.

4. The PTC heating device as described in claim 3, characterized in that, The sealing plug includes a limiting body and a sealing body connected in sequence. The cross-section of the limiting body is larger than the cross-section of the sealing body, and the sealing body is inserted into the heating cavity to form the sealing part. The limiting body is inserted into the clearance channel and abuts against the end face of the outer shell.

5. The PTC heating device as described in claim 1, characterized in that, The outer side of the housing is provided with a locking block, and the sealing element is sleeved on the outside of the housing and engages with the locking block.

6. The PTC heating device as described in claim 1, characterized in that, Both the positive electrode and the negative electrode include a conductive portion and a connecting portion connected to the conductive portion. The conductive portion is attached to the outside of the PTC heating element and is electrically connected to the PTC heating element. The cross-section of the connecting portion is smaller than the cross-section of the conductive portion and extends out of the heating cavity through the seal.

7. The PTC heating device as described in claim 1, characterized in that, The heating cavity includes a receiving area, a transition area, and an installation area distributed in sequence. The cross-section of the receiving area is rectangular, and the PTC heating element is disposed in the receiving area. The cross-section of the installation area is larger than the cross-section of the receiving area.

8. The PTC heating device as described in claim 7, characterized in that, The seal is inserted into the installation area.

9. The PTC heating device as described in claim 7, characterized in that, The housing has a limiting boss located in the mounting area, and the sealing element is inserted into the mounting area and abuts against the limiting boss.

10. The PTC heating device as described in claim 1, characterized in that, The top of the insulating sleeve has a clearance opening through which the conductive module can pass.

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