Combined heating device and use method thereof

Abstract

The invention provides a combined heating device and a using method thereof. The combined heating device comprises a circumferential heating device and an axial heating device arranged on one side of the circumferential heating device. The circumferential heating device can solve the problem that the tobacco matrix at the high position is difficult to heat. In addition, the axial heating device comprises a foamed ceramic body, and an infrared coating is arranged on the side, making contact with the circumferential heating device, of the foamed ceramic body. Wherein the infrared coating can serve as the only heat source of airflow heating and infrared radiation heating at the same time, so that the airflow heating mode and the infrared radiation heating mode are adopted for axial combined heating, it is guaranteed that the heat value of infrared radiation can be fully utilized, energy consumption is low, meanwhile, airflow heating can be achieved, and the heating efficiency is improved. It is guaranteed that the axial heat transfer distance is long, the heat transfer contact area is sufficient, and the heat transfer space is evenly distributed.

Description

Technical Field

[0001] The invention belongs to the technical field of cigarettes, and in particular relates to a combined heating device and a use method thereof. Background Art

[0002] At present, low-temperature cigarette heating devices mainly use inner core heating or circumferential heating. The heat transfer of both heating methods relies on contact heat conduction and is transferred along the radial direction of the cigarette. Since the radius of the cigarette is shorter than the length of the cigarette, the radial heat transmission distance is shorter than the axial transmission, the heat conduction path is short, and the heat transfer efficiency is high. However, both circumferential heating and inner core heating methods use the heating element to conduct heat by contact, and the contact area will affect the efficiency of heat conduction. In addition, the temperature of the heating element is generally above 300°C, and the tobacco matrix close to the heating element is prone to gelatinization. Moreover, for the circumferential heating method, the heat first needs to pass through the cigarette paper of the cigarette, which will not only block the conduction of heat, but also absorb heat, making it difficult to cover up the paper smell.

[0003] In comparison, axial heating in the form of radiation and convection can solve the above problems. The axial heating method heats along the axial path without passing through the cigarette paper, avoiding the heating of the cigarette paper and solving the problem of paper smell in the smoke. In addition, the heat transfer in the radial direction (cigarette cross section) of the axial heating method is uniform. However, the heating path of the axial heating method is longer than that of the circumferential heating method, and there is a greater temperature gradient in the axial direction.

[0004] It can be seen that there are certain problems with the single circumferential heating method or the axial heating method. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a combined heating device and a method for using the combined heating device, wherein the combined heating device can fully utilize the heat energy and the tobacco matrix of the cigarette is more uniform.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a combined heating device, comprising:

[0008] Circumferential heating device;

[0009] An axial heating device disposed on one side of the circumferential heating device;

[0010] The axial heating device comprises a foam ceramic body, and a side of the foam ceramic body in contact with the circumferential heating device is provided with an infrared coating.

[0011] Preferably, the infrared coating consists of a conductive material and an infrared radiation material.

[0012] Preferably, the conductive material is selected from any one or more of tin oxide, zinc oxide, silver oxide or copper oxide.

[0013] Preferably, the infrared radiation material is selected from any one or more of carbon materials, zirconium-titanium oxides, iron oxides, iron nitrides or iron carbides.

[0014] Preferably, the resistance of the infrared coating is 0.4-5 Ω.

[0015] Preferably, the infrared coating has a thickness of 0.3-250 μm.

[0016] Preferably, the infrared radiation wavelength of the infrared coating at 150-300° C. is 2-20 μm*.

[0017] Preferably, the cross section of the foam ceramic body is circular; the length of the foam ceramic body is 5 to 10 cm.

[0018] Preferably, the porosity of the foam ceramic body is 80-95%.

[0019] Preferably, the circumferential heating device comprises a heating cylinder, and a heating element is arranged on the outer side of the heating cylinder.

[0020] Preferably, the length of the heating cylinder is 5 to 10 cm.

[0021] Preferably, the length of the heating element is smaller than the length of the heating cylinder.

[0022] Preferably, the heating element is arranged on a side of the heating cylinder away from the side in contact with the foam ceramic body.

[0023] Preferably, the combined heating device further comprises a filter element.

[0024] Preferably, the filter element is arranged on the other side of the circumferential heating device away from the axial heating device.

[0025] In a second aspect, the present invention provides a method for using the above-mentioned combined heating device, comprising the following steps:

[0026] The cigarette tobacco matrix is ​​placed in the circumferential heating device, and at the same time, one side of the cigarette tobacco matrix contacts the axial heating device, and the circumferential heating device and the axial heating device are started to heat the tobacco matrix.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides a combined heating device, which includes a circumferential heating device and an axial heating device arranged on one side of the circumferential heating device. In the present invention, the axial heating device includes a foam ceramic body, and an infrared coating is arranged on the side of the foam ceramic body that contacts the circumferential heating device. Among them, the infrared coating, as a heat source of the foam ceramic body, can radiate infrared rays and heat the foam ceramic body, and the foam ceramic body can heat the air therein. Therefore, the infrared coating can be used as the only heat source for airflow heating and infrared radiation heating at the same time. In this way, the two heating methods of airflow and infrared radiation are used as axial combined heating. While ensuring that the calorific value of infrared radiation can be fully utilized and the energy consumption is low, it can also use airflow heating to ensure that the distance of heat transfer in the axial direction is relatively long, the heat transfer contact area is sufficient, and the heat transfer space is evenly distributed.

[0029] Furthermore, the heating path of axial heating is long and there is a greater temperature gradient in the axial direction. Therefore, the present invention arranges circumferential heating to perform heat compensation on the tobacco matrix in the distal axial direction to make up for the problem that the tobacco matrix in the distal axial direction is difficult to be heated. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of a combined heating device in the present invention;

[0031] Among them, 1 is a heating cylinder, 2 is a foam ceramic body, 3 is a heating element, 4 is an infrared coating, 5 is a tobacco matrix, and 6 is a filter;

[0032] Figure 2 A top view of the surface of the upper end of the foam ceramic body;

[0033] Among them, 21 are pores;

[0034] Figure 3 The front view and cross-section of tobacco pile samples with different thicknesses;

[0035] Figure 4 The reflectivity data diagram of tobacco pile samples with different thicknesses;

[0036] in, Figure 4 a) is the reflectivity data of tobacco pile samples with different thicknesses (wavelength: 700~1500 nm); Figure 4 b) is an enlarged view of the reflectivity data of tobacco pile samples with different thicknesses (wavelength: 750~1000 nm);

[0037] Figure 5 This is the transmittance data diagram of a tobacco pile sample with a thickness of 5 mm;

[0038] in, Figure 5a) is the transmittance data of a tobacco pile sample with a thickness of 5 mm (wavelength: 700~1500 nm); Figure 5 b) is an enlarged view of the transmittance data of a tobacco pile sample with a thickness of 5 mm (wavelength: 750~1000 nm). DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0040] The present invention provides a combined heating device, comprising:

[0041] Circumferential heating device;

[0042] An axial heating device is arranged on one side of the circumferential heating device. In some embodiments of the present invention, the structural schematic diagram of the combined heating device is as follows: Figure 1 As shown, the circumferential heating device is designed as a heating cylinder 1, and the axial heating device is designed as a foam ceramic body 2. The side of the foam ceramic body 2 that contacts the heating cylinder 1 is also provided with an infrared coating 4. According to the present invention, when the above-mentioned combined heating device is used to heat cigarette shreds, it is preferred to extend the shreds into the heating cylinder 1 and make the bottom of the shreds contact the infrared coating 4.

[0043] In the present invention, the length of the heating cylinder, i.e., the depth of the tobacco shreds when subsequently heated, is generally controlled to be 5-10 cm, preferably 6-8 cm. It can be understood that the heating cylinder is used to heat the tobacco shreds above a height of 5-10 cm.

[0044] In the present invention, the inner wall of the heating cylinder is covered with a peripheral heating element 3 for providing heat transfer in the circumferential direction. The heating method of the heating element includes but is not limited to resistance wire heating and / or infrared radiation heating. It should be noted that in the present invention, the heating element 3 does not completely cover the inner wall of the heating cylinder, and the length of the heating element is generally less than the length of the heating cylinder. Figure 1 The heating element is preferably arranged on the side away from the heating cylinder and in contact with the foam ceramic body. In this way, the bottom of the tobacco can be heated by the axial heating device, while the tobacco that cannot be heated by the axial heating device can be heated by the circumferential heating device.

[0045] Reference Figure 1In the present invention, the axial heating device is a foam ceramic body 2, and considering the subsequent heating of tobacco, its cross section is preferably circular. For details, please refer to the attached Figure 2 , wherein 21 is the pore of the foam ceramic body 2, and the porosity of the foam ceramic body 2 is preferably 80-95%, more preferably 85-90%. In some embodiments of the present invention, the length of the foam ceramic body is 5-10 cm, preferably 6-8 cm.

[0046] In the present invention, the axial heating device preferably adopts a combination of infrared radiation heating and airflow heating, and the two types of heating methods can be used in a non-contact manner.

[0047] It should be noted that the electric-thermal conversion efficiency of infrared radiation heating is high, reaching more than 90%. Infrared radiation is generally heat radiation or temperature radiation. Once the infrared rays are absorbed by an object, the energy of the infrared radiation is converted into heat energy, heating the object to increase its temperature. When infrared rays propagate directly to the surface of an object at the speed of light, and its emission frequency matches the natural frequency of the object's molecular motion, it will cause strong vibrations of the molecules of the object, and intense friction will occur inside the object to generate heat.

[0048] The generation of infrared rays is closely related to temperature, and the radiation energy and distribution of infrared rays by wavelength are determined by the surface temperature of the object. The radiation energy of the surface of an object is proportional to the fourth power of the surface temperature of the object; the higher the temperature of an object, the more it can radiate near-infrared rays with shorter wavelengths, while when the temperature is lower, it can radiate infrared rays with longer wavelengths.

[0049] Infrared heat radiation is used as a heating method for low-temperature cigarettes. If the infrared radiation direction is set in the radial position of the cigarette, it is easy to be intercepted by the impermeable aluminum foil cigarette paper. The transmittance of infrared radiation through the aluminum foil cigarette paper is very low, and the reflectivity is high, causing other parts to be heated. If the infrared radiation energy is increased, the temperature of the infrared radiation generating device needs to be increased, and a heat insulation device must be designed, and energy loss is inevitable.

[0050] Since infrared radiation has reflection and transmission in the axial direction of the cigarette, there are two corresponding technical indicators: reflectivity and transmittance. It can be seen that these two technical indicators at the axial position of the cigarette are of vital importance to whether the infrared radiation method can be used as a heat source. Therefore, the present invention examines the transmittance and reflectivity of infrared radiation at the axial depth of the cigarette.

[0051] The specific experiments are as follows:

[0052] The tobacco pile samples reconstructed according to the apparent bulk density of low-temperature cigarettes are as follows: Figure 3 The cylindrical samples with thickness of 5 mm and 10 mm were respectively recorded as sample 1# and sample 2# (the apparent bulk density of tobacco leaves is 0.22 g / cm3 ).

[0053] The transmittance and reflectance data of sample 1# and sample 2# were measured using an ultraviolet / visible / near-infrared diffuse reflectance tester (Perkin Elmer, Lambda 1050).

[0054] Among them, the reflectivity data of the two samples in the 700~1500 nm infrared band are as follows: Figure 4 As shown. Figure 4 a) and enlarged image ( Figure 4 b) It can be seen that sample 1# and sample 2# with different thicknesses have comparable reflectivity, indicating that the apparent morphology and apparent packing density of the two samples are comparable.

[0055] The transmittance data of the two samples in the 700~1500 nm infrared band are as follows: Figure 5 As shown. Among them, the transmittance of the 10 mm thick 2# sample is 0, and the instrument cannot measure it. Figure 5 Only the transmittance data of the 5 mm thick 1# sample in the 700~1500 nm infrared band are shown. Figure 5 a) It can be seen that the infrared transmittance of the 5 mm thick 1# sample is only 1~5%. Figure 5 b) It can be seen that sharp infrared transmission peaks can be observed at wavelengths of 800 nm, 820 nm and 863 nm, indicating that sample 1# has preferential transmission performance for infrared rays of some wavelengths.

[0056] Therefore, the present invention draws the following conclusions: in the heating mode of infrared radiation, about 15% of the energy is reflected, a sample with a thickness of 5 mm can transmit 5% of the energy, and 80% of the energy is absorbed.

[0057] In the present invention, the infrared radiation heating method can fully utilize the heat source and has low energy consumption, but the heating path of the infrared radiation heating method is short.

[0058] Airflow heating is a method of producing smoke by heating tobacco substrate with high-temperature air heated by heating elements. In this heating method, the heat transfer distance is relatively long, the heat transfer contact area is sufficient, and the heat transfer space is evenly distributed. However, airflow heating requires a lot of power to heat the heat storage body, and the heat storage body needs to heat the air to 280~300℃. The high temperature of the components will bring a series of problems, such as heat insulation and energy loss.

[0059] Therefore, the present invention adopts both the infrared radiation heating method and the airflow heating method as the heating methods of the axial heating device, and the advantages and disadvantages of the two methods complement each other.

[0060] In summary, refer to the attached Figure 1In the present invention, the side of the foam ceramic body 2 in contact with the heating cylinder 1 is also provided with an infrared coating 4, and the infrared coating 4 is a composite infrared radiation coating, and the composite infrared radiation coating is sprayed on the end surface of the foam ceramic body by a conductive material and an infrared radiation material in a mass ratio of (3~6):(7~4), preferably a ratio of (4~5):(5~6) to form an infrared coating 4. The infrared coating 4 generates heat and radiates infrared rays after being energized. Wherein, the conductive material is any one or more of tin oxide, zinc oxide, silver oxide or copper oxide. The infrared radiation material is any one or more of carbon material, zirconium-titanium oxide, iron oxide, iron nitride or iron carbide.

[0061] In the present invention, the resistance of the infrared coating 4 is 0.4-5 Ω, preferably 1-3 Ω; the thickness is 0.3-250 μm, preferably 10-200 μm, and the infrared radiation wavelength at 150-300° C. is between 2-20 μm.

[0062] In the present invention, the infrared coating 4 acts as a heat source for the foam ceramic body 2, radiates infrared rays, and heats the foam ceramic body 2, and the foam ceramic body 2 can heat the air therein, so the infrared coating 4 can act as a heat source for both airflow heating and infrared radiation heating, thereby ensuring that both airflow heating and infrared radiation heating exist in the axial direction. Among them, the infrared radiation heating method can make full use of the heat source and has low energy consumption, but the heating path of the infrared radiation heating method is short, while the heat transfer distance of the airflow heating method is long, the heat transfer contact area is sufficient, and the heat transfer space is evenly distributed, which can effectively make up for the shortcomings of infrared radiation.

[0063] In addition, as mentioned above, a sample with a thickness of 5 mm can transmit 5% of the energy and absorb 80% of the energy. Therefore, the present invention selects to perform circumferential heating on the tobacco substrate at a position more than 5 mm away from the infrared coating 4 to perform heat compensation.

[0064] In some embodiments of the present invention, the combined heating device further comprises a filter element, which is arranged on the other side of the circumferential heating device away from the axial heating device. Figure 1 , the filter element is a filter tip 6.

[0065] In one embodiment of the present invention, the combined heating device is specifically as follows: a foam ceramic body 2 is placed at the bottom of the cigarette holding cavity, the upper end surface of the foam ceramic body 2 is covered with an infrared coating 4 (with pores 21), and a heating cylinder 1 is covered with a heating element 3 (such as a resistor) at a height of more than 5 mm from the bottom of the cigarette holding cavity, which uses circumferential heating to perform temperature compensation on the distal axial direction of the cigarette.

[0066] The present invention also provides a method for using the combined heating device, comprising the following steps:

[0067] Put the cigarette tobacco matrix into the circumferential heating device, and at the same time, the bottom of the cigarette tobacco matrix contacts the axial heating device, and start the circumferential heating device and the axial heating device to heat the tobacco matrix.

[0068] In summary, the combined heating device provided by the present invention adopts airflow heating and infrared radiation heating, combines heating in the axial direction, and heats the cigarette in the circumferential direction by a heating element (such as a resistor) above a certain height, and has the following advantages:

[0069] (1) The infrared coating acts as a heat source for the foam ceramic body, radiating infrared rays and heating the foam ceramic body, while the foam ceramic body can heat the air passing through it. The infrared coating can serve as the only heat source for both airflow heating and infrared radiation heating;

[0070] (2) Since infrared radiation energy is related to temperature, increasing the infrared radiation energy will increase the temperature of the foam ceramic body. In addition, the energy reflected by the tobacco matrix is ​​also used by the foam ceramic. The heat of the ceramic body is transferred to the inflowing air, and the high-temperature air heats the tobacco matrix, so the energy can be fully utilized. Simply by optimizing the length of the ceramic body, the insulation problem of the heat source can be effectively solved;

[0071] (3) The airflow heating method can make up for the short heating path problem of the infrared radiation heating method, while the high-position circumferential resistance heating can further make up for the problem that the high-position tobacco matrix is ​​difficult to heat;

[0072] (4) This technical solution fully utilizes the thermal energy and reduces the difficulty of thermal insulation design to a certain extent.

[0073] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A combined heating device, characterized in that: include: Circumferential heating device; An axial heating device disposed on one side of the circumferential heating device; The axial heating device comprises a foam ceramic body, and an infrared coating is arranged on a side of the foam ceramic body in contact with the circumferential heating device.

2. The combined heating device according to claim 1, characterized in that: The infrared coating is composed of a conductive material and an infrared radiation material; The conductive material is selected from any one or more of tin oxide, zinc oxide, silver oxide or copper oxide; the infrared radiation material is selected from any one or more of carbon material, zirconium-titanium oxide, iron oxide, iron nitride or iron carbide.

3. The combined heating device according to claim 1 or 2, characterized in that: The infrared coating has a resistance of 0.4-5Ω and a thickness of 0.3-250 μm; The infrared radiation wavelength of the infrared coating at 150-300° C. is 2-20 μm.

4. The combined heating device according to any one of claims 1 to 3, characterized in that: The cross section of the foam ceramic body is circular; the length of the foam ceramic body is 5 to 10 cm; The porosity of the foam ceramic body is 80-95%.

5. The combined heating device according to any one of claims 1 to 4, characterized in that: The circumferential heating device comprises a heating cylinder, and a heating element is arranged on the outer side of the heating cylinder.

6. The combined heating device according to claim 5, characterized in that: The length of the heating cylinder is 5 to 10 cm.

7. The combined heating device according to claim 5 or 6, characterized in that: The length of the heating element is smaller than the length of the heating cylinder.

8. The combined heating device according to any one of claims 5 to 7, characterized in that: The heating element is arranged on a side of the heating cylinder that is away from the heating cylinder and in contact with the foam ceramic body.

9. The combined heating device according to any one of claims 1 to 8, characterized in that: The combined heating device also includes a filter element; The filter element is arranged on the other side of the circumferential heating device away from the axial heating device.

10. A method for using the combined heating device according to any one of claims 1 to 9, characterized in that: The following steps are involved: The cigarette tobacco matrix is ​​placed in the circumferential heating device, and at the same time, one side of the cigarette tobacco matrix contacts the axial heating device, and the circumferential heating device and the axial heating device are started to heat the tobacco matrix.

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