Heating non-combustion device and durable heating pipe thereof

Abstract

The utility model belongs to the technical field of heating non-combustion devices, and particularly relates to a heating non-combustion device and a durable heating tube thereof, which comprise a cylindrical metal base material, an insulating layer and a conductive heating layer, and are characterized in that the outer surface of the cylindrical metal base material is provided with patterned continuous grooves; the insulating layer covers the outer surface of the cylindrical metal base material, the conductive heating layer is arranged in a groove of the metal base material, and the insulating layer is arranged between the cylindrical metal base material and the conductive heating layer in the groove. Compared with the prior art, when the flat metal pipe is subjected to thermal expansion, the expansion degrees of all positions are equivalent, after the grooves are formed in the metal pipe, the grooves absorb most expansion, the size change is reduced, the insulating layer is not prone to falling off after repeated heating, the resistance change is within 0.3% after aging is conducted for 10100 times, and the service life is greatly prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of heating without burning devices, and in particular relates to a heating without burning device and a durable heating tube thereof. Background Art

[0002] The heating tube is one of the commonly used heating elements in heat-not-burn devices. The current preparation method is to coat the surface of the metal substrate with insulating paste, dry and sinter it, then print conductive paste on the insulating layer to form a circuit pattern, and then dry and sinter it. The resistance and heating effect can be adjusted by adjusting the shape of the circuit pattern.

[0003] The composition of the insulating paste is mainly glass ceramics, which has poor surface bonding with the metal surface. The thermal expansion coefficients of glass ceramics and metals are also quite different. For example, the linear expansion coefficient of stainless steel is about 10.5-14×10 -6 / ℃, the linear expansion coefficient of microcrystalline glass ceramics is about 8-9×10 -6 / ℃, the dimensional change rate of stainless steel tubes is greater after being heated. After the heating tubes with metal substrates are used for a certain period of time, the insulating layer falls off, causing the conductive layer to fall off, thereby reducing the atomization effect or even failing, making the service life of the heating without burning device shorter.

[0004] In order to solve the above technical problems, it is necessary to develop a metal-based heating tube whose surface coating is not easy to fall off, so as to increase the service life of the heating without burning device. Summary of the Invention

[0005] The purpose of the utility model is to address the deficiencies of the prior art and provide a metal-based heating tube with a surface coating that is not easily peeled off, thereby increasing the service life of the heating-without-combustion device.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A durable heating tube includes a cylindrical metal substrate, an insulating layer and a conductive heating layer. The outer surface of the cylindrical metal substrate has a patterned continuous groove. The insulating layer covers the outer surface of the cylindrical metal substrate. The conductive heating layer is arranged in the groove of the metal substrate. In the groove, the insulating layer is arranged between the cylindrical metal substrate and the conductive heating layer.

[0008] The outer surface of the cylindrical metal substrate has patterned, continuous grooves. When the metal substrate expands due to heat, the thickness of the grooves is smaller, resulting in less metal expansion. The thickness of the metal outside the grooves is greater, resulting in greater expansion toward the grooves. This combined effect maintains a relatively stable width and length of the grooves, thus preventing the insulating layer within the grooves from falling off. The cylindrical metal substrate is preferably made of stainless steel.

[0009] The conductive heating layer is arranged on the outer surface of the cylindrical metal substrate. Each step in the preparation method is a method that is easily implemented in the prior art.

[0010] The conductive heating layer is formed by printing a conductive heating paste at the groove and then sintering it; the groove is processed by etching; and the pattern of the groove is a two-segment or three-segment zigzag pattern.

[0011] Since the glass of the insulating layer will break when rolled after sintering, it needs to be rolled first and then coated with insulating slurry and sintered. The specific preparation method includes the following steps: first, patterned continuous grooves are processed on the surface of the sheet metal substrate, and then the sheet metal substrate is rolled into a cylindrical metal substrate, and the grooves are on the outer surface of the cylindrical metal substrate. The outer surface of the cylindrical metal substrate is then coated with insulating slurry and sintered to form an insulating layer, and the conductive heating slurry is printed on the grooves and sintered to form a conductive heating layer.

[0012] The conductive heating layer is located within the grooves of the cylindrical metal substrate, so the shape of the grooves corresponds to the shape of the conductive heating layer. The circuit shape of the conductive heating layer must first be determined, and the metal substrate is then machined according to this determined circuit shape. The groove depth is 0.01-0.5mm. The specific method for forming the patterned continuous grooves on the metal substrate can adopt conventional methods in the existing art, including etching, stamping, and laser processing.

[0013] The grooves can adopt the patterns in the prior art, with one stage of continuous heating, or two or more stages of zoned heating. They can be reasonably set according to the actual heating effect needs, and will not be described in detail.

[0014] Preferably, the metal substrate is formed into a groove by etching, and the surface roughness of the groove is relatively high, which further improves the bonding force between the groove and the insulating layer.

[0015] Preferably, the innermost layer of the inner surface of the heating tube is a heat reflective coating. The heat reflective coating can reduce heat loss, make the heat more concentrated, and make the temperature inside the heating tube more uniform.

[0016] Preferably, the outermost layer of the outer surface of the heating tube is a thermal insulation layer. On the one hand, the thermal insulation layer can protect the conductive heating layer arranged on the outer surface, and on the other hand, it can also play a role of thermal insulation to reduce heat loss.

[0017] The conductive heating layer is prepared from metal-glass or metal ceramic slurry, such as platinum slurry, silver slurry and other commercial slurries, which can be reasonably selected according to the resistance value requirements.

[0018] The insulating layer is made by sintering glass ceramics or low melting point ceramic slurry, forming a liquid phase during sintering and forming a dense structure after sintering. Beneficial effects

[0019] When a flat metal pipe expands thermally, the degree of expansion is similar everywhere. However, after grooves are set in the metal pipe, the grooves absorb most of the expansion, the dimensional change is reduced, and the insulation layer is not easy to fall off after repeated heating. After aging 10,100 times, the resistance value changes within 0.3%, which greatly extends the service life.

[0020] The utility model also provides a heating without burning device, which comprises the durable heating tube of the utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the unfolded heating tube in Example 1.

[0022] Figure 2 for Figure 1 Cross-sectional view at position A in the middle.

[0023] Figure 3 This is a cross-sectional view of the unfolded heating tube in Example 2.

[0024] Figure 4 This is a three-dimensional diagram of the heating tube with two-zone heating in Example 3.

[0025] Figure 5 This is an expanded view of the heating tube for two-zone heating in Example 3.

[0026] Attached photos

[0027] 1- cylindrical metal substrate; 2- conductive heating layer; 3- insulating layer; 4- thermal insulation layer; 5- heat reflective coating. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. Example

[0030] For easier understanding, the structure of the heating tube is shown in the expanded diagram. The schematic diagram of the heating tube after expansion is as follows: Figure 1As shown, it is a section of continuous heating. There is a patterned continuous groove on the cylindrical metal substrate 1. The surface of the cylindrical metal substrate 1 is coated with an insulating layer 3. A conductive heating layer 2 is printed in the groove on the insulating layer 3. Two leads are welded at both ends of the conductive heating layer 2. The pattern of the conductive heating layer 2 is a section of continuous heating. Figure 1 The cross-sectional view at position A is as follows: Figure 2 The conductive heating layer 2 is formed by printing a conductive heating paste in the groove and then sintering it; the groove is processed by etching; and the pattern of the groove is a two-segment or three-segment zigzag pattern.

[0031] Example 1-1

[0032] The preparation method of this embodiment is: patterned continuous grooves are processed on the surface of the sheet metal by etching, and then the sheet metal substrate is rolled into a cylindrical metal substrate 1, and then the outer surface of the cylindrical metal substrate 1 is coated with an insulating paste and sintered to form an insulating layer 3, and the grooves are printed with a conductive heating paste and sintered to form a conductive heating layer 2.

[0033] Example 1-2

[0034] The difference from Example 1-1 is that the groove is processed by stamping.

[0035] Comparative Example 1: A sheet metal substrate is rolled into a cylindrical metal substrate, an insulating paste is coated on the entire outer surface of the cylindrical metal substrate, and then sintered to form an insulating layer, and a conductive heating paste is printed and sintered to form a conductive heating layer.

[0036] The three heating tubes in Examples 1-1, 1-2, and Comparative Example 1 were subjected to a durability test. The test method was as follows: first, the initial resistance of the heating tube was measured. The tube was then energized for 240 seconds and de-energized for 60 seconds at the product's rated voltage for approximately 10,000 cycles. The tube was then placed at 25°C for more than 2 hours. The resistance after the durability test was compared with the resistance before the test. A resistance change rate of less than 1% was considered acceptable. The results are shown in the table below. In the examples, after the grooves were set on the metal substrate, the resistance change was very small, within 0.3%. However, the resistance change of the heating tube prepared with a flat metal substrate was close to 2%, and the atomization effect was significantly reduced in the later stage.

[0037] serial number Initial resistance (Ω) Resistance after aging 10010 times (Ω) Rate of change Example 1-1 0.523891 0.524414 0.1% Example 1-2 0.544739 0.543319 -0.26% Comparative Example 1 0.572852 0.562205 -1.86% Example

[0038] On the basis of Example 1, the outermost layer of the heating tube is coated with a heat-insulating layer 4, and the innermost layer is coated with a heat-reflecting coating 5. The cross-sectional diagram of the heating tube is shown in FIG. Figure 3 shown.

[0039] The thicker the outer insulation layer and the inner heat reflection layer, the higher the heating efficiency of the heating pipe and the better the heat collection effect. Example

[0040] Based on Example 1, the heating circuit is set to symmetrical two-zone heating.

[0041] The three-dimensional diagram of the heating pipe is as follows Figure 4 As shown, the expanded schematic diagram is as follows Figure 5 shown.

[0042] Based on the disclosure and teachings of the above description, those skilled in the art may also make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and any modifications and variations of the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although certain specific terms are used in this description, these terms are for convenience of description only and do not constitute any limitation to the present invention.

Claims

1. A durable heating tube comprising a cylindrical metal substrate, an insulating layer, and a conductive heating layer, characterized in that: The outer surface of the cylindrical metal substrate has patterned continuous grooves, The insulating layer covers the outer surface of the cylindrical metal substrate. The conductive heating layer is arranged in the groove of the metal substrate. In the groove, the insulating layer is provided between the cylindrical metal substrate and the conductive heating layer; The conductive heating layer is formed by printing a conductive heating paste in the groove and then sintering it; The groove is processed by etching; The pattern of the groove is a two-segment or three-segment zigzag pattern.

2. The durable heating tube according to claim 1, wherein: The depth of the groove is 0.01-0.5 mm.

3. The durable heating tube according to claim 1, wherein: The resistance value of the durable heating tube changes within 0.3% after aging 10100 times.

4. The durable heating tube according to claim 1, wherein: The innermost layer of the inner surface of the durable heating tube is a heat reflective coating.

5. The durable heating tube according to claim 1, wherein: The outermost layer of the outer surface of the durable heating tube is a heat-insulating layer.

6. A heat-not-burn device, characterized in that: The invention comprises the durable heating tube according to any one of claims 1 to 5.

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