Central rod-shaped heating body and low-temperature smoking set

Abstract

The utility model belongs to the technical field of smoking articles, and discloses a central rod-shaped heating element and a low-temperature smoking set, the central rod-shaped heating element comprises an insulating base and a heating element body, the heating element body comprises an inner tube electrode, an outer tube electrode, an inner heating tube, an outer heating tube and an inner and outer tube connecting piece; one end of the inner tube electrode is inserted into a mounting hole in the insulating base in a matching manner, and the other end is connected with the inner heating tube; one end of the outer tube electrode is fixedly connected with the insulating base, and the other end of the outer tube electrode is connected with the outer heating tube; and one end of the outer heating tube far away from the outer tube electrode is provided with an inner-outer tube connecting piece which is fixedly connected with the inner heating tube to form a series access. The two SUS304 pipes with different diameters and different resistance values are connected to form a double-pipe series connection structure with the inverted-U-shaped cross section, the double-pipe series connection structure serves as the heating body, the surface temperature uniformity of the heating body is improved, the surface roughness is low, the manufacturing cost is reduced, assembling is convenient, and application and popularization value is achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of smoking articles and relates to a central rod-shaped heating element and a low-temperature smoking article. Background Art

[0002] The central rod heating method offers advantages such as fast heating speed, short waiting time for the first puff, high vapor volume, low energy consumption per cigarette, compact size, and low surface temperature. However, most existing central rod heating elements on the market are made of 95% printed and sintered porcelain, which has a complex production process, low production efficiency, and high cost. The current ex-factory price is approximately 15 yuan, which is close to two-thirds of the price of the entire temperature control PCB board. The heating element accounts for a disproportionately high proportion of the total device cost, and the entire heating device has a short lifespan of only about 12-15 months, which is not conducive to the market promotion of heated cigarette devices.

[0003] Furthermore, the surface roughness of existing 95% ceramic heating rods on the market makes it difficult to remove a cigarette from the heating element after heating. The TCR values ​​of existing 95% ceramic heating rods on the market vary significantly after sintering, leading to imprecise temperature control and the need for high-temperature TCR calibration in subsequent production. This increases the number of production and assembly steps and the cost. Utility Model Content

[0004] The purpose of the utility model is to solve the above shortcomings of the existing 95 porcelain heating rod, and to design and develop a rod-shaped heating body with extremely low cost, low surface roughness and production without high temperature and high precision.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A central rod-shaped heating element, comprising an insulating base and a heating element body, wherein the heating element body comprises an inner tube electrode, an outer tube electrode, an inner heating tube, an outer heating tube, and an inner and outer tube connector;

[0007] One end of the inner tube electrode is matched and inserted into the mounting hole on the insulating base, and the other end is connected to the inner heating tube;

[0008] The outer tube electrode is sleeved outside the inner tube electrode, one end of which is fixedly connected to the insulating base, and the other end of which is connected to the outer heating tube;

[0009] An inner and outer tube connector is provided at one end of the outer heating tube away from the outer tube electrode and is fixedly connected to the inner heating tube to form a series passage;

[0010] Preferably, the resistance of the inner heating tube is greater than the resistance of the outer heating tube.

[0011] Preferably, the resistance of the inner tube electrode is smaller than the resistance of the inner heating tube, and the resistance of the outer tube electrode is smaller than the resistance of the outer heating tube.

[0012] Preferably, the heating element body is made of SUS304 (stainless steel 304).

[0013] Preferably, the outer diameter of the inner heating tube is 1.3-1.4 mm, preferably 1.3 mm; the outer diameter of the outer heating tube is 2.0-2.1 mm, preferably 2.0 mm; the wall thickness of the inner heating tube and the outer heating tube is 0.03-0.05 mm, preferably 0.05 mm.

[0014] Preferably, the inner and outer tube connector is provided with an inner tube limiting shoulder at one end, an outer tube limiting shoulder in the middle, and the other end is in a cone shape.

[0015] Preferably, the inner tube electrode, outer tube electrode, inner heating tube and outer heating tube are all coaxially arranged.

[0016] Preferably, a temperature measuring element is further provided in the inner heating tube, one end of the temperature measuring element is inserted into a positioning hole provided at one end of the inner and outer tube connecting piece, and the other end passes through the inner tube electrode and extends to the outside of the insulating base. In this way, the internal space of the inner tube electrode can be fully utilized to assemble the temperature measuring element and obtain the actual heating temperature of the heating body.

[0017] Preferably, the insulating base is further provided with a pair of electrode wire holes, in which electrode wires are installed, and the pair of electrode wires are respectively connected to the inner tube electrode and the outer tube electrode.

[0018] Preferably, the insulating base is a PCB board.

[0019] A low-temperature smoking device comprises the above-mentioned central rod-shaped heating element.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This utility model utilizes the high resistivity of existing SUS304 tubes. Two SUS304 tubes of different diameters and resistance values ​​are connected by laser welding to form a double-tube series structure with an inverted U-shaped cross section. This structure serves as the main heating element. Because the resistance of the inner heating tube is greater than that of the outer heating tube, the inner heating tube generates a higher temperature than the outer heating tube. Furthermore, a gap exists between the inner and outer heating tubes, so the outer heating tube, while also receiving heat from the inner heating tube, resulting in a more uniform surface temperature. The wall thickness of the inner and outer tube electrodes is correspondingly smaller than that of the inner and outer heating tubes, reducing the heat dissipated by the inner and outer tube electrodes and the conduction of heat to the smoking device, thereby increasing the heating temperature of the cigarettes. The inner heating tube and the inner tube electrodes are equipped with thermocouples for real-time monitoring of the heating temperature. The heating element material cost is low, the manufacturing process is simple, and the unit price of the heating element is less than 5 yuan, which is about 30% of the unit price of existing heating elements on the market. The built-in temperature-sensing thermocouple eliminates the need for high-temperature calibration on the production line during production. The assembly process is simple, the production cost of the device is low, and the service life is long, making it valuable for widespread application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a front cross-sectional view of the central rod-shaped heating element.

[0023] Figure 2 It is a side sectional view of the central rod-shaped heating element.

[0024] Figure 3 Axis side view of the central rod-shaped heating element Figure 1 .

[0025] Figure 4 Axis side view of the central rod-shaped heating element Figure 2 .

[0026] Figure 5 This is an axial view of the insulating base.

[0027] Figure 6 Schematic diagram of the three-dimensional inner and outer pipe connector.

[0028] Figure 7 This is an exploded view of the central rod-shaped heating element.

[0029] Figure 8 Schematic diagram of the assembly process of the central rod-shaped heating element.

[0030] Figure 9 This is a schematic diagram of a low-temperature smoking device.

[0031] In the figure: 1-inner and outer tube connector, 101-thermocouple positioning hole, 102-outer tube limiting shoulder, 103-inner tube limiting shoulder, 2-outer tube first welding seam, 3-inner tube first welding seam, 4-outer heating tube, 5-inner heating tube, 6-thermocouple, 601-thermocouple ceramic insulation layer, 7-thermocouple wire, 8-thermocouple wire insulation layer, 9-outer tube second welding seam, 10-inner tube second welding seam, 11-outer tube electrode , 12-inner tube electrode, 13-PCB board, 1301-inner tube electrode mounting hole, 1302-positive wire hole, 1303-negative wire hole, 1304-fixing screw hole, 1305-outer tube electrode pad, 1306-inner tube electrode pad, 14-positive wire, 15-negative wire, 16-cigarette, 17-shell, 18-cigarette holder, 19-fixing screw, 20-temperature control board, 21-battery. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0033] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", "one end", "the other end", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0034] Example 1; see Figure 1-7 ;

[0035] This embodiment provides a central rod-shaped heating element, which is one of the preferred embodiments of the present utility model, including an insulating base and a heating element body, wherein the heating element body includes an inner tube electrode 12, an outer tube electrode 11, an inner heating tube 5, an outer heating tube 4, and an inner-outer tube connector 1; one end of the inner tube electrode 12 is matched and inserted into the mounting hole on the insulating base, and the other end is connected to the inner heating tube 5; the outer tube electrode 11 is sleeved outside the inner tube electrode 12, one end is fixedly connected to the insulating base, and the other end is connected to the outer heating tube 4; an inner-outer tube connector 1 is provided at the end of the outer heating tube 4 away from the outer tube electrode 11, which is fixedly connected to the inner heating tube 5 to form a series path; the resistance of the inner heating tube 5 is greater than the resistance of the outer heating tube 4.

[0036] The inner-outer tube connector 1 is provided with an outer tube limiting shoulder 102 in the middle and an inner tube limiting shoulder 103 at one end. The outer tube limiting shoulder 102 and the inner tube limiting shoulder 103 respectively provide assembly limits for the end of the outer heating tube 4 away from the outer tube electrode 11 and the end of the inner heating tube 5 away from the inner tube electrode 12. Laser welding is used to secure the outer tube 4 and the inner heating tube 5 together, forming a first outer tube weld seam 2 and a first inner tube weld seam 3 at the connection point. This coaxial connection between the outer heating tube 4 and the inner heating tube 5 is achieved. The first outer tube weld seam 2 allows for a smooth transition between the inner-outer tube connector 1 and the outer wall of the outer heating tube 4. Together, the outer heating tube 4, the inner-outer tube connector 1, and the inner heating tube 5 form a coaxial dual-tube series structure with an inverted U-shaped cross-section. The total resistance of the two tubes in series is between 0.50 and 0.65 Ω. The other end of the inner-outer tube connector 1 is tapered to facilitate insertion of the cigarette into the heating element. Alternatively, the inner-outer tube connector 1 and the outer heating tube 4 and the inner heating tube 5 can be connected by an interference fit.

[0037] The outer tube electrode 11 is made of SUS304 (stainless steel 304). Laser welding is performed between the outer tube electrode 11 and the outer heating tube 4, forming a second outer tube weld seam 9 at the joint. This secures the outer tube electrode 11 to the outer heating tube 4 and provides a smooth transition between the outer walls. The outer tube electrode 11 is thicker than the outer heating tube 4 (to prevent contact between the outer tube electrode 11 and the inner tube electrode 12, an electrode insulation layer is preferably provided). Its length is shorter than that of the outer heating tube 4, resulting in a lower resistance and lower heat generation during operation. Furthermore, the thermal conductivity of SUS304 at room temperature is 16 W / m•K, which is relatively low compared to steel (with a thermal conductivity of approximately 50 W / m•K) and aluminum alloy (approximately 120-200 W / m•K). Therefore, the heat generated by the external heating tube 4 during operation is relatively small and is conducted to the insulating base and the surface of the smoking device through the external tube electrode 11 , thereby improving user experience and avoiding burns.

[0038] The inner tube electrode 12 is made of SUS304 and is laser welded to the inner heating tube 5, forming a second inner tube weld seam 10 at the weld, firmly connecting the inner tube electrode 12 to the inner heating tube 5. The inner tube electrode 12 has a thicker wall than the inner heating tube 5 and is shorter than the inner heating tube 5, resulting in a lower resistance and lower heat generation during operation. Therefore, the heat generated by the inner heating tube 5 during operation is conducted to the insulating base and the surface of the smoking device through the inner tube electrode 12, which reduces the risk of burns to the user.

[0039] The heating element itself is made of SUS304, including the inner heating tube 5, outer heating tube 4, and inner and outer tube connector 1. The different components of the heating element are all made of the same SUS304 material, primarily due to its low production cost and smooth surface with low surface roughness. However, the wall thickness of each component varies. Since the tubes are connected in series, the thicker electrode walls reduce the resistance of the electrodes. Lower resistance means lower power and, consequently, less heat generated. This results in the heat of the heating element being primarily concentrated in the heating element itself, particularly in the inner and outer heating tube sections.

[0040] The insulating base adopts a PCB board 13. The material of the PCB board 13 is FR4, which is one of the most commonly used PCB materials. It is made of glass fiber reinforced epoxy resin-based material and has good insulation, heat resistance and mechanical properties, and low thermal conductivity. The PCB board 13 is provided with an inner tube electrode mounting hole 1301 running through it from top to bottom. The length of the inner tube electrode 12 is longer than that of the outer tube electrode 11. One end of the inner tube electrode 12 is matched and inserted into the inner tube electrode mounting hole 1301; the upper surface of the PCB board 13 is provided with an outer tube electrode pad 1305, and the lower surface is provided with an inner tube electrode pad 1306. One end of the outer tube electrode 11 is welded and fixed to the PCB board 13 at the outer tube electrode pad 1305, and one end of the inner tube electrode 12 is welded and fixed to the PCB board 13 at the inner tube electrode pad 1306.

[0041] The PCB board 13 is provided with a positive wire hole 1302 and a negative wire hole 1303, which are respectively connected to the positive wire 14 and the negative wire 15 through soldering. One end of the positive wire 14 and the negative wire 15 are connected to the inner tube electrode 12 and the outer tube electrode 11 respectively, and the other end is connected to the power supply inside the smoking device; the PCB board 13 is provided with a fixing screw hole 1304, which is convenient for fixing the entire heating element inside the smoking device.

[0042] In addition, a temperature measuring element is provided in the heating body, and the temperature measuring element is a thermocouple. A thermocouple positioning hole 101 is provided in the center of one end of the inner and outer tube connecting piece 1. One end of the thermocouple 6 is assembled in the thermocouple positioning hole 101 and is bonded and fixed in the thermocouple positioning hole 101. The thermocouple wire 7 passes through the inner heating tube 5. The thermocouple wire 7 is provided with a thermocouple wire insulation layer 8 for insulation. The thermocouple 6 located in the inner heating tube 5 is coated with a ceramic insulation layer 601 for insulation.

[0043] The working principle of this embodiment is:

[0044] SUS304 has a resistivity of 7.15x106Ω·m and can be used as a heating wire in the industrial field. SUS304 can maintain a certain stability at high temperatures. When working as a heating wire to generate heat, even if the temperature rises, it can still maintain its structural stability and will not be quickly damaged or seriously degraded, thereby ensuring the continuity of its heating function. It also has good corrosion resistance. In different usage environments (such as heating environments where it may be exposed to moisture, etc.), SUS304 is not easily corroded, thereby extending the service life of the heating wire and reducing the risk of performance degradation and failure caused by corrosion. Using the SUS304 tube as the external heating tube 4, its outer wall surface roughness is low, which facilitates the removal of the cigarette from the heating element after heating is completed.

[0045] Existing thin-walled, small-diameter SUS304 tubes on the market have high resistivity and can be used as heating elements. However, the length of the tobacco portion of a cigarette is fixed (typically 10-11mm), so the heating element must also be within this range. Despite their high resistivity, a 10-11mm long, 2mm outer diameter, and 0.05mm wall thickness SUS304 tube has a resistance of only 0.26Ω. At a voltage of 3.7V, the current will reach approximately 14A, which is too high for batteries and other components to withstand. Currently, typical heating element resistance is between 0.5-0.8Ω, and a power rating of around 20W is more suitable. To achieve a resistance of 0.5-0.8Ω for the SUS304 tube within a length of 10-11mm, another small SUS304 tube with an outer diameter of 1.3mm, a length of 10-11mm, a wall thickness of 0.05mm, and a resistance of 0.39Ω was axially sleeved onto the first SUS304 tube. The upper ends of the two tubes were limited by a SUS304 turning part (i.e., inner and outer tube connector 1) and connected by laser welding, forming a two-tube series structure with an inverted U-shaped cross section. The total resistance of the two tubes in series was 0.65Ω, achieving the required resistance range.

[0046] Although the inner heating tube 5 draws more power than the outer heating tube 4 during heating, resulting in a higher temperature, the outer electrode 11 has a diameter of 2.0-2.1 mm and a wall thickness of 0.15-0.2 mm, while the inner electrode 12 has a diameter of 1.3-1.4 mm and a wall thickness of 0.15-0.2 mm (the outer wall of the inner electrode 12 smoothly connects to the inner heating tube 5). The gap between the inner and outer heating tubes is approximately 0.3 mm. Therefore, surrounded by the tobacco, the temperature difference between the inner and outer heating tubes is minimal, resulting in a relatively uniform temperature distribution. This is because the inner heating tube 5 is hotter than the outer heating tube 4, while the outer heating tube 4 is heated as a whole. With the gap between the inner and outer heating tubes, the heat dissipated from the inner heating tube 5 to the outside through the air in the gap is more evenly distributed. When the outer heating tube 4 itself heats, it is also subjected to the high temperature of the inner heating tube, improving the surface temperature uniformity of the outer heating tube 4. Compared with existing 95-ceramic printed heating wire heating, this eliminates the formation of a small, high-temperature spot, thereby reducing the degree of adhesion between the tobacco and the heating element due to sintering. The inner and outer tube electrodes at the other end of the inner and outer heating tubes are also made of SUS304, with thicker walls and lower resistance than the heating tubes. When connected in series with the inner and outer heating tubes, they will not generate more heat during operation.

[0047] After the inner and outer tube electrodes are connected to the inner and outer heating tubes, they are fixed to the PCB board 13 by soldering, and then fixed to the smoking device through the fixing screw holes on the PCB board 13. The material of the PCB is FR4, which is made of glass fiber reinforced epoxy resin-based material with excellent insulation, heat resistance and mechanical properties. The thermal conductivity of the non-conductive board of FR4 is 0.2 W / m / K. Using the PCB board 13 to fix the heating element can effectively prevent the heat of the heating element from being transferred to the surface of the main body of the smoking device, thereby reducing the surface temperature of the smoking device. Although the inner tube electrode 12 and the outer tube electrode 11 are also made of SUS304 material, as electrodes, they do not need to be too long. The smaller their length is compared to the inner heating tube 5 and the outer heating tube 4, the greater the uniform temperature length of the heating rod inserted into the interior of the cigarette.

[0048] The assembly process of the central rod-shaped heating element in this embodiment is as follows: first, the inner heating tube 5 and the inner tube electrode 12 are welded, and then one end of the thermocouple 6 is inserted into the thermocouple positioning hole 101 at one end of the inner and outer tube connector 1 and fixed by bonding, and then the inner heating tube 5 and the inner tube electrode 12 are sleeved on the thermocouple 6, and the end of the inner heating tube 5 is positioned with the inner tube limiting shoulder 103 on the inner and outer tube connector 1, and fixed by welding at the connection; then the outer heating tube 4 and the outer tube electrode 11 are welded, and then the two are sleeved on the inner tube electrode 12, and the end of the outer heating tube 4 is positioned with the outer tube limiting shoulder 102 on the inner and outer tube connector 1, and fixed by welding at the connection. Afterwards, one end of the inner tube electrode 12 is inserted into the inner tube electrode mounting hole 1301 of the PCB board 13, and the inner tube electrode 12 is welded and fixed to the inner tube electrode pad 1306 on the lower surface of the PCB board 13, and the outer tube electrode 11 is welded and fixed to the outer tube electrode pad 1305 on the upper surface of the PCB board 13; the positive wire 14 and the negative wire 15 are respectively inserted into the positive wire hole 1302 and the negative wire hole 1303 on the PCB board 13 and fixed, and then the positive wire 14 and the negative wire 15 are connected to the inner tube electrode 12 and the outer tube electrode 11, and the central rod-shaped heating element described in this embodiment can be obtained.

[0049] Furthermore, in other embodiments of the present invention, the inner and outer electrodes 12 and 11, which are made of SUS304 tubes in Example 1, can be replaced with other low-cost materials with lower resistance than SUS304, thereby also achieving the effect of reducing heat transfer from the heating element to the surface of the smoking device. The inner and outer heating tubes 5 and 4 can also be made of custom tubes with similar properties to SUS304.

[0050] Example 2: Figure 9 ;

[0051] This embodiment provides a low-temperature smoking device, comprising the central rod-shaped heating element, housing 17, cigarette holder 18, temperature control board 20, and battery 21 described in Example 1. The central rod-shaped heating element is mounted on an insulating base within housing 17 via screws 19. A cigarette 16 is inserted into the heating chamber within cigarette holder 18 and then mounted on the central rod-shaped heating element. During operation, the heating element's temperature is measured via a thermocouple 6 and controlled via the temperature control board 20. All other components except the central rod-shaped heating element are conventional and will not be described in detail here.

[0052] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any modifications or replacements made to the technical solution by other technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the connotation of the technical solution of the present invention.

Claims

1. A central rod-shaped heating element, comprising an insulating base and a heating element body, characterized in that: The heating element body comprises an inner tube electrode (12), an outer tube electrode (11), an inner heating tube (5), an outer heating tube (4), and an inner and outer tube connector (1); One end of the inner tube electrode (12) is matched and inserted into the mounting hole on the insulating base, and the other end is connected to the inner heating tube (5); The outer tube electrode (11) is sleeved outside the inner tube electrode (12), one end of which is fixedly connected to the insulating base, and the other end of which is connected to the outer heating tube (4); An inner and outer tube connector (1) is provided at one end of the outer heating tube (4) away from the outer tube electrode (11), and the inner heating tube (5) is fixedly connected to form a series passage.

2. The central rod-shaped heating element according to claim 1, wherein: The resistance of the inner heating tube (5) is greater than the resistance of the outer heating tube (4).

3. The central rod-shaped heating element according to claim 2, wherein: The resistance of the inner tube electrode (12) is smaller than the resistance of the inner heating tube (5), and the resistance of the outer tube electrode (11) is smaller than the resistance of the outer heating tube (4).

4. The central rod-shaped heating element according to claim 3, wherein: The heating element body is made of 304 stainless steel.

5. The central rod-shaped heating element according to claim 4, wherein: The outer diameter of the inner heating tube (5) is 1.3-1.4 mm; the outer diameter of the outer heating tube (4) is 2-2.1 mm; and the wall thickness of the inner heating tube (5) and the outer heating tube (4) is 0.03-0.05 mm.

6. The central rod-shaped heating element according to claim 1, wherein: The inner and outer tube connector (1) is provided with an inner tube limiting shaft shoulder (103) at one end, an outer tube limiting shaft shoulder (102) at the middle, and the other end is in a cone-shaped tip.

7. The central rod-shaped heating element according to any one of claims 1 to 6, characterized in that: A temperature measuring element is also provided in the inner heating tube (5), one end of the temperature measuring element is inserted into a positioning hole provided at one end of the inner and outer tube connector (1), and the other end passes through the inner tube electrode (12) and extends to the outside of the insulating base.

8. The central rod-shaped heating element according to any one of claims 1 to 6, characterized in that: The insulating base is also provided with a pair of electrode wire holes, in which electrode wires are installed. The pair of electrode wires are respectively connected to the inner tube electrode (12) and the outer tube electrode (11).

9. The central rod-shaped heating element according to any one of claims 1 to 6, characterized in that: The insulating base adopts a PCB board (13).

10. A low-temperature smoking device comprising the central rod-shaped heating element according to any one of claims 1 to 9.

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