Internal heating rotary kiln
By installing electric heating radiation tubes horizontally in the rotary kiln and installing protective sleeves and ceramic brackets, the problems of environmental pollution and high heat loss caused by the heating method of the rotary kiln are solved, and safety and efficiency are improved.
Patent Information
- Application Number
- CN202420026620.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-05
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2034-01-05
AI Technical Summary
The existing rotary kiln heating methods lead to high environmental pollution and heat loss, and the internal radiation tube is prone to deformation, causing safety hazards.
The internal heating rotary kiln design is adopted. By installing an electric heating radiation tube horizontally in the kiln body, and installing a protective sleeve and a ceramic bracket outside the radiation tube, heating is uniformly used with resistive wires to avoid flue gas emissions, reduce heat loss, and control temperature The unit controls the temperature.
It realizes environmentally friendly heating, reduces heat loss and safety hazards, and improves the safety and application range of equipment.
Smart Images
Figure CN222279275U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of rotary kilns, in particular to an internally heated rotary kiln. Background Art
[0002] The rotary kiln is a common thermal equipment, which is widely used in cement, metallurgy, ceramics, environmental protection and other industries. At present, the heating method of the rotary kiln on the market is mainly to heat the kiln by heat radiation from the outer cylinder, and to heat the kiln by radiating heat from the flue gas through external equipment. The heat transfer efficiency is low and the loss is high, which will cause cost waste.
[0003] In the internally heated regenerative rotary kiln of patent CN110057190A, blast furnace gas is burned by regenerative burners installed at both ends of metal radiation tubes, so that the heat generated is radiated to the powder material inside the rotary kiln and heats it, and the traditional heating from the outer cylinder is converted to heating from the kiln, which reduces a certain amount of heat loss. However, the regenerative burners and blast furnace gas in the patent are arranged at both ends of the rotary kiln, and when combustion heating is used, an exhaust port is required to discharge the flue gas. When the flue gas is discharged, on the one hand, the flue gas tail gas causes environmental pollution, and on the other hand, the hot gas will be discharged from the exhaust pipe, which will also take away a large amount of heat and cause heat loss. In addition, the patent is a single-sided air inlet and outlet structure. Under the influence of gravity and high temperature, the internal radiation tube may be deformed, causing safety hazards. With the rapid development of industry, the requirements for thermal energy consumption and safety factor of rotary kilns are getting higher and higher, and the above-mentioned heating method cannot meet the use requirements well. Utility Model Content
[0004] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and utility model name of this application to avoid blurring the purpose of this section, specification abstract and utility model name, and such simplifications or omissions cannot be used to limit the scope of the utility model.
[0005] In view of the problems existing in the above-mentioned existing air flow mill slag discharge process, the utility model is proposed. The technical problem solved by the utility model is that the existing rotary kiln heating method requires the exhaust of flue gas, which will cause environmental pollution and high heat loss, and the internal heat radiation tube is prone to deformation, causing safety hazards.
[0006] In order to solve the above technical problems, the utility model provides the following technical solutions: an internally heated rotary kiln includes a rotary kiln and a radiation tube, the rotary kiln includes a kiln body, a kiln head cover, a kiln tail cover and a spiral feeding rod, the kiln head cover and the kiln tail cover are fixedly installed and sleeved on the two ends of the kiln body, the spiral feeding rod extends from the center of the kiln head cover into the kiln body to complete the feeding, the radiation tube avoids the spiral feeding rod and extends from the kiln head cover and extends from the kiln tail cover, and is fixed in the kiln body; the radiation tube includes a flange, a resistance wire and a heat preservation area, the resistance wire is distributed on the entire radiation tube, the heat preservation area is arranged at both ends of the radiation tube, flanges are arranged on the heat preservation area, and the connection and fixation of the radiation tube are realized by the flange.
[0007] As a preferred solution of the internally heated rotary kiln described in the utility model, the outside of the radiation tube is also covered with an outer protective sleeve, the overall length of the outer protective sleeve is greater than the overall length of the radiation tube, and can cover the entire radiation tube, and a rotary kiln connecting flange and a radiation tube connecting flange are arranged at the head of the outer protective sleeve, the rotary kiln connecting flange is arranged at the tail end of the insulation zone of the radiation tube and is connected to the kiln head cover and the kiln tail cover, and the radiation tube connecting flange is arranged at the front end of the outer protective sleeve and is connected to the flange.
[0008] As a preferred solution of the internally heated rotary kiln described in the utility model, the radiation tube can be arranged in plurality. When the radiation tube is arranged in plurality, the plurality of radiation tubes are connected by support sleeves.
[0009] As a preferred solution of the internally heated rotary kiln described in the utility model, when the radiation tubes are provided in plurality, the heat preservation zone is provided only on the extending side of the radiation tubes extending out of the kiln head cover and the kiln tail cover.
[0010] As a preferred solution of the internally heated rotary kiln described in the utility model, when the radiation tube is provided in plurality, it is connected to an outer protective sleeve outside the radiation tube, a support sleeve limiting ring is provided on the connecting side of the outer protective sleeve, and the support sleeve is provided between the support sleeve limiting rings of two outer protective sleeves.
[0011] As a preferred solution of the internally heated rotary kiln described in the utility model, a plurality of ceramic brackets are arranged between the resistance wires in the radiation tube, and the resistance wires pass through the ceramic brackets.
[0012] As a preferred solution of the internally heated rotary kiln described in the utility model, support sleeve reinforcement ribs are welded on the upper and lower ends of the outer side wall of the support sleeve.
[0013] As a preferred solution of the internally heated rotary kiln described in the utility model, the ratio of the distance from the rotary kiln connecting flange to the tail end on the outer protective sleeve to the overall length of the outer protective sleeve is 1:7.
[0014] As a preferred solution of the internally heated rotary kiln described in the utility model, the ratio of the distance between the installation position of the support sleeve limiting ring and the vertex of the outer protective sleeve to the length of the outer protective sleeve is 1:14.
[0015] As a preferred solution of the internally heated rotary kiln described in the utility model, wherein: the radiation tube is also connected to a temperature control unit component, and the temperature control unit component is connected to the resistance wire to control the temperature of the resistance wire.
[0016] Beneficial effects of the utility model: The internal heating rotary kiln constructed by the utility model has the following advantages:
[0017] (1) The electric heating radiant tube is fixedly installed horizontally inside the rotary kiln body to heat the kiln body from the inside to avoid the generation of smoke and pollution to the environment. The resistance wire is distributed throughout the radiant tube to make the temperature of each part uniform and avoid deformation. In addition, the part of the radiant tube extending out of the kiln body is set as a heat preservation part, which can further reduce heat loss.
[0018] (2) A protective cover is provided outside the radiation tube, which not only facilitates the installation of the radiation tube, but also further improves the safety of the device;
[0019] (3) A limiting ring is arranged on the protective sleeve, and a supporting sleeve is installed between the radiation tubes. The number of the radiation tubes can be adjusted according to the length of the rotary kiln body, thereby expanding the scope of application. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:
[0021] Figure 1 This is a schematic structural diagram of an internally heated rotary kiln according to a first embodiment of the utility model;
[0022] Figure 2 This is a schematic diagram of the radiation tube structure of the internally heated rotary kiln according to the first embodiment of the utility model;
[0023] Figure 3 This is a schematic diagram of the protective cover structure of the internally heated rotary kiln according to the first embodiment of the utility model;
[0024] Figure 4 This is a schematic diagram of the support sleeve structure of the internally heated rotary kiln according to the first embodiment of the utility model;
[0025] Figure 5 This is a schematic structural diagram of a second embodiment of the utility model in which there are two radiation tubes for the internally heated rotary kiln.
[0026] The components in the attached drawings are marked as follows: rotary kiln-1; kiln body-11; kiln head cover-12; kiln tail cover-13; screw feed rod-14; radiation tube-2; flange-21; resistance wire-22; insulation zone-23; ceramic bracket-24; outer protective sleeve-3; rotary kiln connecting flange-31; radiation tube connecting flange-32; support sleeve limit ring-33; support sleeve-4; support sleeve reinforcement rib-41; temperature control unit assembly-5. DETAILED DESCRIPTION
[0027] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the utility model, but not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary persons in the field without creative work should fall within the scope of protection of the utility model.
[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0029] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.
[0030] The utility model is described in detail with reference to the schematic diagram. When describing the embodiments of the utility model, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the utility model. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.
[0031] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0032] In the present utility model, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integrated connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two original components. For ordinary technicians in this field, the specific meanings of the above terms in the utility model can be understood according to specific circumstances.
[0033] Example 1
[0034] Reference Figure 1 and 2 The embodiment provides an internally heated rotary kiln, comprising a rotary kiln 1 and a radiation tube 2, wherein: the rotary kiln 1 comprises a kiln body 11, a kiln head hood 12, a kiln tail hood 13 and a spiral feed rod 14, the kiln head hood 12 and the kiln tail hood 13 are fixed at both ends of the kiln body 11, in the rotary kiln 1, the kiln body 11 is driven by a rotary motor to perform a rotary motion, the kiln head hood 12 and the kiln tail hood 13 are sleeved at both ends of the kiln body 11 to seal the kiln body 11, and the kiln head hood 12 and the kiln tail hood 13 are installed on the ground and are fixed components, and an extended A cylindrical structure is provided, which is sleeved on both ends of the kiln body 11 to avoid affecting the rotary motion of the kiln body 11, and a sealing structure is provided at the connection position to complete the sealing of the kiln body 11; a spiral feed rod 14 is inserted into the center position of the kiln head hood 12 to input the material into the kiln body 11, and a radiation tube 2 is inserted into the kiln head hood 12 at a position avoiding the spiral feed rod 14, and the radiation tube 2 extends from the kiln head hood 12 and extends from the kiln tail hood 13, passing through the interior of the entire kiln body 11, and since the kiln head hood 12 and the kiln tail hood 13 are fixed, the radiation tube 2 is fixed in the kiln body 11.
[0035] Furthermore, the radiation tube 2 includes a flange 21, a resistance wire 22 and an insulation zone 23, wherein the resistance wire 22 is distributed throughout the radiation tube 1, the insulation zone 23 is arranged at both ends of the radiation tube 2, and the resistance wire 22 is wrapped, and a flange 21 is arranged on the insulation zone 23, the radiation tube 2 extends from the kiln head hood 12 and the kiln tail hood 13, the extended portion is the insulation zone 23 of the radiation tube 2, and the radiation tube 2 can be installed on the kiln head hood 12 and the kiln tail hood 13 through the flange 21.
[0036] When the internal heating rotary kiln is used, the spiral feed rod 14 fills the material into the kiln body 11, and the resistance wire 22 in the radiation tube 2 is energized. The resistance wire 22 generates heat in the kiln body 11, thereby heating the material in the kiln body 11. Since the kiln head cover 12 and the kiln tail cover 13 are both stationary, the radiation tube 2 is fixedly installed on the kiln head cover 12 and the kiln tail cover 13 through the flange 21, so the radiation tube 2 is also stationary. When the kiln body 11 of the rotary kiln drives the internal material to rotate, the resistance wire 22 gradually moves inside. Heat generation can speed up the material heating process, and since the radiation tube 2 and the kiln head cover 12 and the kiln tail cover 13 are installed on the insulation area 23, the heat generated by the resistance wire 22 will not be lost. On the contrary, the insulation area 23 can also insulate the external resistance wire 22, reducing heat loss. This heating method directly heats the kiln through the heat radiation of the radiation tube, which is environmentally friendly heating and will not produce tail waste and other substances due to high heat. In addition, the radiation tube directly radiates heat in the kiln, with minimal heat energy loss, and electric heating is convenient and quick to use.
[0037] It should be noted that, in the embodiment, the resistance wire 22 used may be a U-shaped resistance wire, which heats more evenly and has excellent electrical properties, and can improve the safety of the equipment. In addition, the insulation area 23 on the radiation tube 2 includes an insulation shell and a filling material. In actual application, the insulation shell may use metal materials or ceramic materials, and the filling material may use high-temperature resistant materials such as ceramic fiber, glass wool, and perlite to prevent heat from dissipating from the radiation tube 2.
[0038] In this embodiment, refer to Figure 3 The outside of the radiation tube 2 is also covered with an outer protective sleeve 3. The overall length of the outer protective sleeve 3 is longer than that of the radiation tube 2, and the radiation tube 2 can be completely wrapped. A rotary kiln connecting flange 31 and a radiation tube connecting flange 32 are arranged at the head of the outer protective sleeve 3. The rotary kiln connecting flange 31 is arranged at the tail end of the insulation zone 23 of the radiation tube 2. The rotary kiln connecting flange 31 is connected to the kiln head cover 12 and the kiln tail cover 13 to fix the outer protective sleeve on the rotary kiln. Since the installation position of the rotary kiln connecting flange 31 is the tail end of the insulation zone 23, the part where the radiation tube 2 and the outer protective sleeve 3 extend out of the kiln body 11 is the insulation zone 23, so as to prevent the heat of the radiation tube 2 from being dissipated outside the kiln. In addition, the radiation tube connecting flange 32 is arranged at the tail end of the outer protective sleeve 3, and the radiation tube connecting flange 32 is connected to the flange 21 on the radiation tube 2 to fix the radiation tube 2 inside the outer protective sleeve 3.
[0039] It should be noted that, in the present embodiment, the installation process of the outer protective sleeve 3 and the radiation tube 2 is as follows: the radiation tube 2 is inserted into the interior of the outer protective sleeve 3, and the outer protective sleeve 3 has at least one opening at the top and bottom for the radiation tube 2 to be inserted. After the radiation tube 2 is inserted, the flange 21 on the radiation tube 2 cooperates with the radiation tube connecting flange 32 to fix the radiation tube 2 inside the outer protective sleeve 3. In the embodiment, the flange 21 can be arranged at the end of the insulation zone 23 to facilitate installation and fixation. When the radiation tube 2 is fixed inside the outer protective sleeve 3, the two are inserted into the kiln body 11 as a whole, and the two are fixed in the kiln body 11 through the rotary kiln connecting flange 31.
[0040] In this embodiment, if Figure 2 As shown, a plurality of ceramic brackets 24 are arranged between the resistance wires 22 in the radiation tube 2, and the resistance wires 22 are installed through the ceramic brackets 24. The ceramic brackets 24 arranged in the radiation tube 2 can play a supporting and isolating role, and the radiation tube ceramic should also have good electrical insulation, thermal conductivity, mechanical strength and chemical stability, which can reduce the energy loss of the radiation tube and increase the service life.
[0041] In this embodiment, the radiation tube 2 is connected to the temperature control unit assembly 5, and the temperature control unit assembly 5 is connected to the resistance wire 22 from the tail end of the insulation zone 23 of the radiation tube 2 to control the temperature of the radiation tube 2. The temperature control unit assembly 5 can use an electronic temperature controller, which uses resistance temperature sensing to measure and control the temperature in the kiln. It has stable operation, and in actual application, the temperature controller can achieve temperature control adjustment of 100 to 1000°C in the kiln.
[0042] Example 2
[0043] In this embodiment, different from Embodiment 1, a plurality of radiation tubes 2 can be provided in the kiln body 11. When a plurality of radiation tubes 2 are provided, the plurality of radiation tubes 2 are connected by support sleeves 4 and are transversely installed inside the kiln body 11. In actual application, when the length of the rotary kiln is too long, a single radiation tube 2 cannot cross the entire kiln body 11. Therefore, a plurality of interconnected radiation tubes 2 can be transversely arranged to distribute the radiation tubes 2 in the entire kiln body 11.
[0044] Furthermore, when there are multiple radiation tubes 2, the insulation zone 23 is only set on the protruding side of the radiation tube 2 extending out of the kiln head hood 12 and the kiln tail hood 13; when there are two radiation tubes 2, the two radiation tubes 2 extend from both ends of the kiln head hood 12 and the kiln tail hood 13 respectively, and the insulation zone 23 is set at the part of the radiation tube 2 extending out of the kiln head hood 12 and the kiln tail hood 13; when there are more than two radiation tubes 2, the insulation zone 23 is not set for the radiation tube 2 connected in the middle, and the insulation zone 23 is only set at one end of the radiation tube 2 extending out of the kiln head hood 12 and the kiln tail hood 13 at both ends.
[0045] In this embodiment, each radiation tube 2 is covered with an outer protective sleeve 3. The radiation tubes 2 are connected and the outer protective sleeves 3 are connected. A support sleeve limiting ring 33 is provided at the connection position of the outer protective sleeve 3. The support sleeve 4 is provided between the support sleeve limiting rings 33 of two mutually connected outer protective sleeves 3. The two support sleeve limiting rings 33 limit the support sleeve 4 and realize the connection between the outer protective sleeves 3. Furthermore, support sleeve reinforcing ribs 41 are welded on the outer side walls of the upper and lower ends of the support sleeve 4 to make the support sleeve 4 firm and not easy to deform. The support tube limiting ring 33 can limit the position of the support sleeve 4. The support sleeve 4 can well support the two radiation tubes 2 to prevent the radiation tubes 2 from being deformed by gravity and heat. In addition, this thermal radiation tube electric heating device has a simple structure, reliable strength, easy installation and low equipment cost, and is more suitable for rotary kiln heating, especially in new industries with high requirements for the temperature in the kiln.
[0046] In this embodiment, the ratio of the distance from the rear end of the rotary kiln connecting flange 31 on the outer protective sleeve 3 to the overall length of the outer protective sleeve 3 is 1:7, and the ratio of the distance between the installation position of the support sleeve limiting ring 33 and the vertex of the outer protective sleeve 3 to the length of the outer protective sleeve 3 is 1:14; taking the connection of two 7-meter-long outer protective sleeves 3 as an example, a rotary kiln connecting flange 31 is set 1m away from the front end of the protective sleeve and fixedly connected with the fixed kiln head cover 12, a support tube limiting ring 33 is welded 0.5m away from the rear end of the outer protective sleeve 3 to limit the position of the support sleeve 4, and another 7m-long outer protective sleeve 3 is coaxially inserted into the kiln tail cover 13 at the other end, and the rotary kiln connecting flange 31 is fixedly connected to the kiln tail cover 13 at a distance of 1m from the outer protective sleeve 3, and another support tube limiting ring 33 is also welded 0.5m away from the rear end of the outer protective sleeve 3, and the rear end of the outer protective sleeve 3 is aligned with the other port of the support sleeve 4, so that the two radiation tubes 2 are fixed on the kiln head and kiln tail covers on the same axis.
[0047] It should be noted that the ratio of the installation position of the rotary kiln connecting flange 31 and the support sleeve limiting ring 33 to the overall length of the outer protective sleeve 3 is set to ensure the stability of the connection between the outer protective sleeve 3, but in actual application, the installation positions of the two can also be adjusted according to actual conditions.
[0048] It should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.
Claims
1. An internally heated rotary kiln, comprising a rotary kiln (1) and a radiation tube (2), characterized in that: The rotary kiln (1) comprises a kiln body (11), a kiln head cover (12), a kiln tail cover (13) and a spiral feed rod (14); the kiln head cover (12) and the kiln tail cover (13) are fixedly installed and sleeved on both ends of the kiln body (11); the spiral feed rod (14) extends from the center of the kiln head cover (12) into the kiln body (11) to complete the feeding; the radiation tube (2) avoids the spiral feed rod (14), extends from the kiln head cover (12) and extends from the kiln tail cover (13), and is fixed in the kiln body (11); The radiation tube (2) comprises a flange (21), a resistance wire (22) and a heat preservation zone (23); the resistance wire (22) is distributed on the entire radiation tube (2); the heat preservation zone (23) is arranged at both ends of the radiation tube (2); a flange (21) is arranged on the heat preservation zone (23); and the radiation tube (2) is connected and fixed by means of the flange (21).
2. The internally heated rotary kiln according to claim 1, characterized in that: The radiation tube (2) is also covered with an outer protective sleeve (3). The overall length of the outer protective sleeve (3) is greater than the overall length of the radiation tube (2) and is capable of covering the entire radiation tube (2). A rotary kiln connecting flange (31) and a radiation tube connecting flange (32) are arranged at the head of the outer protective sleeve (3). The rotary kiln connecting flange (31) is arranged at the rear end of the heat preservation zone (23) of the radiation tube (2) and is connected to the kiln head cover (12) and the kiln tail cover (13). The radiation tube connecting flange (32) is arranged at the front end of the outer protective sleeve (3) and is connected to the flange (21).
3. The internally heated rotary kiln according to claim 2, characterized in that: The radiation tube (2) may be provided in plurality, and the plurality of radiation tubes (2) are connected via a support sleeve (4).
4. The internally heated rotary kiln according to claim 3, characterized in that: Part of the radiation tube extends out of the kiln head cover (12) and the kiln tail cover (13), and the insulation zone (23) is arranged on the side where the part of the radiation tube extends out of the kiln head cover (12) and the kiln tail cover (13).
5. The internally heated rotary kiln according to claim 3, characterized in that: The support sleeve (4) is connected to an outer protective sleeve (3) outside the radiation tube (2), a support sleeve limiting ring (33) is provided on the connection side of the outer protective sleeve (3), and the support sleeve (4) is provided between the support sleeve limiting rings (33) of the two outer protective sleeves (3).
6. The internally heated rotary kiln according to claim 1, characterized in that: A plurality of ceramic brackets (24) are arranged between the resistance wires (22) in the radiation tube (2), and the resistance wires (22) pass through the ceramic brackets (24).
7. The internally heated rotary kiln according to claim 3, characterized in that: Support sleeve reinforcing ribs (41) are welded on both upper and lower ends of the outer side wall of the support sleeve (4).
8. The internally heated rotary kiln according to claim 2, characterized in that: The ratio of the distance between the rotary kiln connecting flange (31) and the front end of the outer protective sleeve (3) to the overall length of the outer protective sleeve (3) is 1:
7.
9. The internally heated rotary kiln according to claim 5, characterized in that: The ratio of the distance between the installation position of the support sleeve limiting ring (33) and the rear end of the outer protective sleeve (3) to the length of the outer protective sleeve (3) is 1:
14.
10. The internally heated rotary kiln according to claim 1, characterized in that: The radiation tube (2) is also connected to a temperature control unit assembly (5), and the temperature control unit assembly (5) is connected to the resistance wire (22) to control the temperature of the resistance wire (22).