Heating device for precoated sand preparation

Abstract

The invention provides a heating device for precoated sand preparation, which belongs to the technical field of precoated sand production equipment and comprises a rotary furnace barrel, an electromagnetic heating unit and a furnace cover. Wherein an inner pipe is arranged in the rotary furnace barrel, one end of the inner pipe is fixedly connected with the furnace cover, the other end of the inner pipe is connected with a sliding cover, and a discharging opening used for discharging materials into the rotary furnace barrel is formed in the bottom of the sliding cover. The inner pipe is arranged in the rotary furnace barrel, when the rotary furnace barrel rotates to heat materials, the materials can be added into the inner pipe at the same time, and the redundant space of the rotary furnace barrel is utilized to preheat the materials; after the materials in the rotary furnace barrel are heated and unloaded, the materials in the inner pipe are added into the rotary furnace barrel, and due to the fact that the materials are preheated when inside the inner pipe, the heat needed for heating the materials to the specified temperature is small, the time needed for heating is correspondingly shortened, the production efficiency is improved, and the effects of saving energy and reducing consumption are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of coated sand production equipment, and specifically refers to a heating device for preparing coated sand. Background Art

[0002] The main raw materials of coated sand include high-quality selected natural quartz sand (as the original sand), thermoplastic phenolic resin, hexamethylenetetramine (as the latent curing agent), and calcium stearate (as the isolation lubricant). The preparation process is as follows: First, the original sand is heated to 150 - 180 °C, and the heated sand enters the mixer for mixing. During the mixing process, raw materials such as phenolic resin, iron oxide, hexamethylenetetramine aqueous solution, and calcium stearate are added manually or automatically. After mixing for a certain time, the mixed sand is sent to the crusher for crushing into small granular state, and finally screened and cooled.

[0003] Currently, in the preparation process of coated sand, a rotary furnace is mostly used for heating the original sand. Through the rotation of the rotary furnace, the original sand is turned in the furnace, and the heating is more uniform, and the heating rate is fast. However, in order to make the original sand heated evenly, too much original sand cannot be added into the furnace barrel to avoid a large amount of original sand accumulating at the bottom of the furnace barrel. This results in a large amount of space remaining in the furnace during heating, and the heat is lost with the gas, causing energy loss. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a heating device for preparing coated sand, which at least partially solves the above problems.

[0005] The technical solution adopted by the present invention is as follows: The present invention provides a heating device for preparing coated sand, including: A rotary furnace barrel, and an electromagnetic heating unit for electromagnetic heating is sleeved outside the rotary furnace barrel; A furnace hood, which is arranged at the furnace mouth of the rotary furnace barrel. An outlet for discharging materials is provided at the bottom of the furnace hood, and a feed hopper is provided at the top of the furnace hood; Wherein, an inner tube is arranged inside the rotary furnace barrel, and one end of the inner tube is fixedly connected to the furnace hood. A feeding port is provided at one end of the inner tube close to the feed hopper. The bottom of the feed hopper extends from the feeding port into the interior of the inner tube for feeding materials into the inner tube. The other end of the inner tube is connected with a sliding hood. A discharging port for discharging materials into the rotary furnace barrel is provided at the bottom of the sliding hood. The sliding hood is arranged to be able to slide reciprocally along the axis of the inner tube. When the sliding hood slides to overlap with the inner tube, the discharging port is closed; A shaft tube is arranged inside the inner tube, and a screw blade is arranged outside the shaft tube. When the screw blade rotates, the materials inside the inner tube can be conveyed from the feeding port to the direction of the discharging port.

[0006] Further, the first end of the shaft tube penetrates through the sliding cover and extends into the rotary furnace barrel. A ventilation outlet is provided at the first end of the shaft tube. The second end of the shaft tube penetrates and extends to the outside of the inner tube. An air guiding tube is rotatably connected to the second end of the shaft tube. The air guiding tube extends to the furnace opening of the rotary furnace barrel, and a blower is connected to the air guiding tube.

[0007] Further, a filter net for filtering is provided in the ventilation outlet.

[0008] Further, a support tube is connected by a bearing at the center of the end of the rotary furnace barrel close to the sliding cover, and the first end of the shaft tube is rotatably connected to the support tube.

[0009] Further, a traction unit connected to the sliding cover is provided on the support tube for driving the sliding cover to slide reciprocally.

[0010] Further, the traction unit includes a traction rod, a hydraulic cylinder and a traction frame. The traction rod slides in the support tube. A sliding groove is provided at one end of the support tube located inside the rotary furnace barrel. One end of the traction frame is connected to the sliding cover, and the other end of the traction frame passes through the sliding groove and is connected to the traction rod. The hydraulic cylinder is located outside the rotary furnace barrel, and the telescopic end of the hydraulic cylinder is connected to the traction rod.

[0011] Further, a shaft tube driving unit and a pulley are provided at the second end of the shaft tube. The pulley is sleeved and fixed on the shaft tube, and the output end of the shaft tube driving unit is connected to the pulley through a belt.

[0012] Further, roller groups for supporting the rotary furnace barrel are provided at the bottoms of both ends of the rotary furnace barrel. Roller rings corresponding to the roller groups are sleeved at both ends of the rotary furnace barrel. Any one of the roller groups is connected to a furnace barrel driving unit for driving the rotary furnace barrel to rotate through the roller group.

[0013] Further, a bracket is provided at the bottom of the rotary furnace barrel, and the electromagnetic heating unit, the roller group, the furnace cover, the hydraulic cylinder and the shaft tube driving unit are all supported by the bracket.

[0014] Further, a plurality of charging plates evenly distributed in the circumferential direction are provided on the inner wall of the rotary furnace barrel.

[0015] The beneficial effects achieved by the present invention with the above structure are as follows: 1. By arranging an inner tube in the rotary furnace drum, when the rotary furnace drum rotates to heat the material, the material can be added into the inner tube at the same time, and the extra space of the rotary furnace drum is used to preheat the material. After the material in the rotary furnace drum is heated and unloaded, the material in the inner tube is added into the rotary furnace drum. Since the material has been preheated inside the inner tube, the heat required to heat the material to the specified temperature is small, and the heating time is shortened accordingly, which improves production efficiency and plays a role in energy saving and consumption reduction.

[0016] 2. By setting a shaft tube penetrating inside the inner tube and setting an induced draft duct at one end of the shaft tube, the hot air flow dissipated outward from the furnace mouth is sent into the shaft tube. The shaft tube can heat the material in the inner tube from the inside to improve the utilization rate of heat. An exhaust port is set at the other end of the shaft tube. The hot air flow in the shaft tube is re-discharged into the rotary furnace drum from the exhaust port, so that a circulating hot air flow is formed inside the rotary furnace drum. The flowing hot air flow can make the material in the rotary furnace drum heated more evenly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of a heating device for preparing coated sand proposed in an embodiment of the present invention; Figure 2 A schematic diagram of the internal structure of a heating device for preparing coated sand proposed in an embodiment of the present invention; Figure 3 A schematic structural diagram of a traction unit in a heating device for preparing coated sand proposed in an embodiment of the present invention; Figure 4 A cross-sectional view of a heating device for preparing coated sand proposed in an embodiment of the present invention; Figure 5 A schematic diagram of a state in which a discharge port of a heating device for preparing coated sand provided in an embodiment of the present invention is closed; Figure 6 A schematic diagram of a state in which a discharge port of a heating device for preparing coated sand provided in an embodiment of the present invention is opened; Figure 7 A schematic diagram of the tilted unloading state of a heating device for preparing coated sand proposed in an embodiment of the present invention.

[0018] Among them, 100, bracket; 1, rotary furnace drum; 11, electromagnetic heating unit; 12, roller ring; 13, roller group; 14, lifting plate; 2, furnace hood; 21, feed hopper; 201, discharge port; 3, inner tube; 301, feeding port; 31, shaft tube; 311, exhaust port; 32, dragon blade; 33, sliding cover; 331, discharge port; 4, induced draft duct; 41, fan; 5, support tube; 501, slide; 51, traction rod; 52, hydraulic cylinder; 53, traction frame; 6, shaft tube drive unit; 61, pulley.

[0019] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention. Detailed implementation manners

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0021] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0022] As Figure 1 shown, the present invention provides a heating device for preparing coated sand, including a rotary furnace barrel 1, a furnace hood 2 and a feed hopper 21. An electromagnetic heating unit 11 is sleeved outside the rotary furnace barrel 1. Correspondingly, the rotary furnace barrel 1 is made of a metal material, and the electromagnetic heating unit 11 is used to heat the barrel wall of the rotary furnace barrel 1. The furnace hood 2 is arranged at the furnace mouth of the rotary furnace barrel 1 to reduce the heat loss in the rotary furnace barrel 1. A discharge port 201 for discharging materials is arranged at the bottom of the furnace hood 2. The materials in the rotary furnace barrel 1 are discharged from the furnace mouth into the furnace hood 2 and then discharged from the discharge port 201 at the bottom of the furnace hood 2. The feed hopper 21 is arranged on the furnace hood 2.

[0023] In this way, the materials are put into the rotary furnace barrel 1, and the electromagnetic heating unit 11 heats the barrel wall of the rotary furnace barrel 1. As the rotary furnace barrel 1 rotates, the materials roll along the inner wall of the rotary furnace barrel 1, and the barrel wall of the rotary furnace barrel 1 heats the materials. When discharging materials, the materials are discharged from the furnace mouth of the rotary furnace barrel 1 into the furnace hood 2 and then discharged from the discharge port 201 at the bottom of the furnace hood 2.

[0024] Furthermore, roller sets 13 for supporting the rotary furnace barrel 1 are arranged at both bottom ends of the rotary furnace barrel 1. Roller rings 12 corresponding to the roller sets 13 are sleeved at both ends of the rotary furnace barrel 1. The roller sets 13 are in contact with the roller rings 12. Any one of the roller sets 13 is connected with a furnace barrel driving unit, and the furnace barrel driving unit drives the roller sets 13 to rotate, and the roller sets 13 drive the rotary furnace barrel 1 to rotate.

[0025] In a specific embodiment, the idler set 13 includes two support rollers, which are respectively located on both sides of the rotary furnace shell 1 and support the rotary furnace shell 1 from the bottom. The furnace shell drive unit includes a motor and a speed reducer. The output end of the speed reducer is connected to any one of the support rollers in the idler set 13 to make it a drive roller. After the motor is decelerated and torque-increased by the speed reducer, it drives the support roller to rotate, and the rotary furnace shell 1 is driven to rotate by the support roller.

[0026] Furthermore, a bracket 100 is provided at the bottom of the rotary furnace shell 1, and the electromagnetic heating unit 11, the idler set 13, and the furnace hood 2 are all supported by the bracket 100.

[0027] It should be noted that during installation, the bracket 100 is integrally installed on a support platform with an adjustable pitch angle. When heating the material, the support platform adjusts the angle to tilt the furnace mouth of the rotary furnace shell 1 upward. When the rotary furnace shell 1 rotates, the material can remain in the rotary furnace shell 1 and will not fall from the furnace mouth, continuously heating the material to raise its temperature. When discharging, the furnace mouth of the rotary furnace shell 1 is tilted downward (as Figure 7 shown), and with the rotation of the rotary furnace shell 1 and under the action of gravity, the material can be discharged from the furnace mouth.

[0028] Combined with 2 and Figure 3 shown, a plurality of material lifting plates 14 evenly distributed circumferentially are provided on the inner wall of the rotary furnace shell 1. When the rotary furnace shell 1 rotates, the material lifting plates 14 can convey the material accumulated at the bottom of the rotary furnace shell 1 upward, reduce the accumulation, make it fully contact with the inner wall of the rotary furnace shell 1, and improve the heating efficiency.

[0029] Combined with Figure 2 and Figure 4 shown, an inner tube 3 with one end fixedly connected to the furnace hood 2 is provided inside the rotary furnace shell 1. The inner tube 3 is coaxially arranged with the rotary furnace shell 1 (that is, the inner tube 3 is arranged at the center of the rotary furnace shell 1). At the same time, the outer diameter of the inner tube 3 is smaller than the inner diameter of the rotary furnace shell 1, so that there is enough space between the rotary furnace shell 1 and the inner tube 3 to accommodate the raw materials; A feeding port 301 is provided at one end of the inner tube 3 close to the feed hopper 21. The bottom of the feed hopper 21 extends to the inside of the inner tube 3 through the feeding port 301. The other end of the inner tube 3 is connected with a sliding cover 33. A discharge port 331 for discharging materials into the rotary furnace shell 1 is provided at the bottom of the sliding cover 33. The feed hopper 21 can add materials into the inside of the inner tube 3 through the feeding port 301, and the materials inside the inner tube 3 can be discharged through the discharge port 331, so that the inner tube 3 can play the role of storing materials.

[0030] In this way, when the rotary drum 1 rotates to heat the material, the material can be added into the inner tube 3 at the same time. By utilizing the extra space in the rotary drum 1, the material is preheated. After the material in the rotary drum 1 is heated and discharged, the material in the inner tube 3 is added into the rotary drum 1. Since the material has been preheated when it is inside the inner tube 3, the amount of heat required to heat the material to the specified temperature is small, and the heating time required is correspondingly shortened, thus improving the production efficiency and playing a role in energy conservation and consumption reduction.

[0031] Further, the sliding cover 33 is arranged to be able to slide reciprocally along the axis of the inner tube 3. When the sliding cover 33 slides to a position where it does not overlap with the inner tube 3, the discharge port 331 is in an open state (as Figure 6 shown), and the material inside the inner tube 3 can be discharged from the discharge port 331 into the rotary drum 1. When the sliding cover 33 slides to a position where it overlaps with the inner tube 3, the discharge port 331 is blocked and closed by the inner tube 3 (as Figure 5 shown).

[0032] Still further, a shaft tube 31 is provided inside the inner tube 3. A spiral blade 32 is provided on the outer side of the shaft tube 31. The shaft tube 31 can drive the spiral blade 32 to rotate and control the rotation direction of the spiral blade 32, so that when the spiral blade 32 rotates, the material inside the inner tube 3 can be pushed by the spiral blade 32 and conveyed from the feeding port 301 towards the discharge port 331.

[0033] In this way, when adding the material into the inner tube 3 from the feeding port 301, by utilizing the spiral blade 32, the material can be pushed into the inside of the inner tube 3, making the inner tube 3 full of the material and avoiding the accumulation of the material at the feeding port 301. When discharging the material from the discharge port 331, by utilizing the spiral blade 32, the material inside the inner tube 3 can be pushed towards the feeding port 301, so as to discharge all the material as much as possible.

[0034] When the rotary drum 1 is heating, the heat inside the rotary drum 1 will be lost outward from the furnace mouth. In order to make full use of the heat, as shown in Figure 4 、 Figure 5 and Figure 6 shown, the first end of the shaft tube 31 penetrates through the sliding cover 33 and extends into the rotary drum 1. A discharge air port 311 is provided at the first end of the shaft tube 31. The second end of the shaft tube 31 penetrates and extends to the outside of the inner tube 3. A draft tube 4 is rotatably connected to the second end of the shaft tube 31. The draft tube 4 extends to the furnace mouth of the rotary drum 1. A fan 41 is connected to the draft tube 4; The fan 41 draws the hot air flow dissipated outward from the furnace mouth into the shaft tube 31 through the induced draft pipe 4 to heat the shaft tube 31. Since the shaft tube 31 passes through the inner tube 3, the shaft tube 31 can heat the material in the inner tube 3 from the inside, thereby improving the utilization rate of heat. At the same time, the hot air flow in the shaft tube 31 is re-discharged into the rotary furnace drum 1 through the exhaust port 311, so that a circulating hot air flow is formed inside the rotary furnace drum 1. The flowing hot air flow can make the material in the rotary furnace drum 1 heated more evenly.

[0035] Furthermore, a filter screen is provided in the exhaust port 311 for filtering. The aperture of the filter screen is smaller than the particle size of the material (i.e., raw sand). The filter screen protects the exhaust port 311 to prevent the material in the rotary furnace drum 1 from entering the shaft tube 31 through the exhaust port 311 .

[0036] Combination Figure 4 , Figure 5 and Figure 6 As shown, a support tube 5 is connected to the center of one end of the rotary furnace drum 1 near the sliding cover 33 through a bearing, and the support tube 5 and the rotary furnace drum 1 can rotate relative to each other, and the first end of the shaft tube 31 is rotationally connected to the support tube 5 through a connecting shaft. At this time, one end of the inner tube 3 is supported by the furnace cover 2, and the other end of the inner tube 3 is supported by the support tube 5. Since the inner tube 3 and the furnace cover 2 are fixed, the inner tube 3 cannot rotate, and the shaft tube 31 is rotationally connected to the support tube 5, which will not affect the rotation of the shaft tube 31.

[0037] Furthermore, a traction unit connected to the sliding cover 33 is provided on the support tube 5 to drive the sliding cover 33 to slide back and forth to realize the opening and closing of the discharge port 331 .

[0038] In a specific embodiment, the traction unit includes a traction rod 51, a hydraulic cylinder 52 and a traction frame 53. The traction rod 51 slides in the support tube 5. One end of the support tube 5 located in the rotary furnace drum 1 is provided with a slide groove 501. One end of the traction frame 53 is connected to the sliding cover 33. The other end of the traction frame 53 passes through the slide groove 501 and is connected to the traction rod 51. The hydraulic cylinder 52 is located on the outside of the rotary furnace drum 1. The telescopic end of the hydraulic cylinder 52 is fixedly connected to the traction rod 51. The hydraulic cylinder 52 is fixedly supported by the bracket 100.

[0039] At this time, the hydraulic cylinder 52, the traction rod 51, the traction frame 53, the support tube 5 and the sliding cover 33 are all in a circumferentially fixed state to prevent the sliding cover 33 from being dragged to rotate circumferentially when the shaft tube 31 rotates, so that the discharge port 331 on the sliding cover 33 is always facing downward to facilitate discharge.

[0040] It should be noted that when the traction frame 53 drives the sliding cover 33 to move, the traction frame 53 slides in the slide groove 501. Therefore, the length of the slide groove 501 is greater than the sliding stroke of the sliding cover 33, so as to avoid the sliding stroke of the traction frame 53 being insufficient and causing the sliding cover 33 to fail to move into place.

[0041] In this way, the telescopic end of the hydraulic cylinder 52 drives the traction rod 51 to reciprocate in the support tube 5, and the traction rod 51 drives the sliding cover 33 to reciprocate through the traction frame 53.

[0042] Combined with Figure 1 and Figure 4 As shown, a shaft tube driving unit 6 and a pulley 61 are provided at the second end of the shaft tube 31. The pulley 61 is sleeved and fixed on the shaft tube 31. The output end of the shaft tube driving unit 6 is connected to the pulley 61 through a belt. The shaft tube driving unit 6 drives the shaft tube 31 to rotate through the traction pulley 61, so that the auger blade 32 rotates to push the material.

[0043] In a specific embodiment, the shaft tube driving unit 6 includes a motor and a speed reducer. The output end of the speed reducer is also connected with a pulley, which is connected with the pulley 61 on the shaft tube 31 through a belt. After the motor is decelerated and torque-increased by the speed reducer, the shaft tube 31 is driven to rotate through the belt.

[0044] The working principle of the present invention: When initially used, materials are added into the inner tube 3 through the feed hopper 21, and the auger blade 32 is used to push the materials into the inner tube 3 and directly discharge them into the rotary furnace cylinder 1 through the discharge port 331. After the materials in the rotary furnace cylinder 1 are added, the sliding cover 33 is moved to coincide with the inner tube 3 to close the discharge port 331, and the added materials are retained inside the inner tube 3. After the inner tube 3 is filled, the feeding is stopped, and the electromagnetic heating unit 11 heats the rotary furnace cylinder 1. The rotary furnace cylinder 1 rotates to heat the materials in the rotary furnace cylinder 1. After the heating is completed, the materials are unloaded from the furnace mouth of the rotary furnace cylinder 1 and discharged through the discharge port 201. After the unloading is completed, the sliding cover 33 is moved to open the discharge port 331, and the preheated materials in the inner tube 3 are conveyed into the rotary furnace cylinder 1 through the discharge port 331 by the auger blade 32 for heating. Then the sliding cover 33 is moved to close the discharge port 331, and new materials are added into the inner tube 3. While the rotary furnace cylinder 1 heats the materials, the newly added materials in the inner tube 3 are preheated. Therefore, the heat required for the materials to be heated to the specified temperature is small, the heating time required is correspondingly shortened, the production efficiency is improved, and the energy consumption is reduced; During the heating, the blower 41 sucks the hot air flow dissipated outward from the furnace mouth into the shaft tube 31 through the air guide pipe 4 to heat the shaft tube 31. Since the shaft tube 31 penetrates the inner tube 3, the shaft tube 31 can heat the materials in the inner tube 3 from the inside, improving the utilization rate of heat. At the same time, the hot air flow of the shaft tube 31 is discharged back into the rotary furnace cylinder 1 through the air discharge port 311, so that a circulating hot air flow is formed inside the rotary furnace cylinder 1. The flowing hot air flow can make the materials in the rotary furnace cylinder 1 heat more evenly.

[0045] In summary of the above embodiments: By providing an inner tube 3 in the rotary furnace barrel 1, when the rotary furnace barrel 1 rotates to heat the material, material can be added into the inner tube 3 at the same time. Utilizing the extra space in the rotary furnace barrel 1, the material is preheated. After the material in the rotary furnace barrel 1 is heated and discharged, the material in the inner tube 3 is added into the rotary furnace barrel 1. Since the material has been preheated when it is inside the inner tube 3, the amount of heat required to heat the material to the specified temperature is small, and the heating time required is correspondingly shortened, improving production efficiency and playing a role in energy conservation and consumption reduction. By providing a through shaft tube 31 in the inner tube 3 and providing an air guiding tube 4 at one end of the shaft tube 31, the hot air flow dissipated outward at the furnace mouth is sent into the shaft tube 31. The shaft tube 31 can heat the material inside the inner tube 3 from the inside, improving the utilization rate of heat. A ventilation opening 311 is provided at the other end of the shaft tube 31, and the hot air flow in the shaft tube 31 is discharged back into the rotary furnace barrel 1 through the ventilation opening 311, causing a circulating hot air flow to form inside the rotary furnace barrel 1. The flowing hot air flow can make the material inside the rotary furnace barrel 1 be heated more evenly.

[0046] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0047] The above describes the present invention and its embodiments. Such description is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and design, without creative efforts, structural modes and embodiments similar to the technical solution without departing from the gist of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A heating device for preparing coated sand, characterized in that: include: A rotary furnace drum (1), wherein an electromagnetic heating unit (11) for electromagnetic heating is sleeved on the outer side of the rotary furnace drum (1); A furnace cover (2) is arranged at the furnace mouth of the rotary furnace drum (1), a discharge port (201) for discharging materials is provided at the bottom of the furnace cover (2), and a feed hopper (21) is provided at the top of the furnace cover (2); The rotary furnace drum (1) is provided with an inner tube (3) having one end fixedly connected to the furnace cover (2); an end of the inner tube (3) close to the feed hopper (21) is provided with a feeding port (301); the bottom of the feed hopper (21) extends from the feeding port (301) to the inside of the inner tube (3) for feeding materials into the inner tube (3); the other end of the inner tube (3) is connected with a sliding cover (33); the bottom of the sliding cover (33) is provided with a discharge port (331) for discharging materials into the rotary furnace drum (1); the sliding cover (33) is configured to be able to slide back and forth along the axis of the inner tube (3); when the sliding cover (33) slides to overlap with the inner tube (3), the discharge port (331) is closed; A shaft tube (31) is provided inside the inner tube (3), and a dragon blade (32) is provided outside the shaft tube (31). When the dragon blade (32) rotates, the material in the inner tube (3) can be transported from the feed port (301) to the discharge port (331).

2. The heating device for preparing coated sand according to claim 1, characterized in that: The first end of the shaft tube (31) passes through the sliding cover (33) and extends into the rotary furnace drum (1); the first end of the shaft tube (31) is provided with an exhaust port (311); the second end of the shaft tube (31) passes through and extends to the outside of the inner tube (3); the second end of the shaft tube (31) is rotatably connected to an induced draft pipe (4); the induced draft pipe (4) extends to the furnace mouth of the rotary furnace drum (1); and the induced draft pipe (4) is connected to a fan (41).

3. The heating device for preparing coated sand according to claim 2, characterized in that: A filter screen for filtering is provided in the air outlet (311).

4. The heating device for preparing coated sand according to claim 1, characterized in that: A support tube (5) is connected to the center of one end of the rotary furnace drum (1) close to the sliding cover (33) via a bearing, and a first end of the shaft tube (31) is rotatably connected to the support tube (5).

5. The heating device for preparing coated sand according to claim 4, characterized in that: The support tube (5) is provided with a traction unit connected to the sliding cover (33) and used for driving the sliding cover (33) to slide back and forth.

6. The heating device for preparing coated sand according to claim 5, characterized in that: The traction unit comprises a traction rod (51), a hydraulic cylinder (52) and a traction frame (53); the traction rod (51) slides in the support tube (5); one end of the support tube (5) located in the rotary furnace drum (1) is provided with a slide groove (501); one end of the traction frame (53) is connected to the sliding cover (33); the other end of the traction frame (53) passes through the slide groove (501) and is connected to the traction rod (51); the hydraulic cylinder (52) is located outside the rotary furnace drum (1); and the telescopic end of the hydraulic cylinder (52) is connected to the traction rod (51).

7. The heating device for preparing coated sand according to claim 6, characterized in that: The second end of the shaft tube (31) is provided with a shaft tube drive unit (6) and a belt pulley (61); the belt pulley (61) is sleeved and fixed on the shaft tube (31); and the output end of the shaft tube drive unit (6) is connected to the belt pulley (61) via a belt.

8. The heating device for preparing coated sand according to claim 7, characterized in that: The bottoms of both ends of the rotary furnace drum (1) are provided with roller groups (13) for supporting the rotary furnace drum (1), and roller rings (12) corresponding to the roller groups (13) are sleeved on both ends of the rotary furnace drum (1), and any one of the roller groups (13) is connected to a furnace drum driving unit for driving the rotary furnace drum (1) to rotate via the roller group (13).

9. The heating device for preparing coated sand according to claim 8, characterized in that: A bracket (100) is provided at the bottom of the rotary furnace drum (1); the electromagnetic heating unit (11), the roller group (13), the furnace cover (2), the hydraulic cylinder (52) and the shaft tube driving unit (6) are all supported by the bracket (100).

10. The heating device for preparing coated sand according to claim 1, characterized in that: The inner wall of the rotary furnace drum (1) is provided with a plurality of material lifting plates (14) evenly distributed in the circumferential direction.

Images