Composite frame type high load bearing middle trough and flight conveyor
By adding a rectangular frame structure and wear sensors to the bottom plate of the middle trough of the scraper conveyor, the problem of insufficient load-bearing capacity of the middle trough under high mining conditions was solved, stress dispersion and reliability were improved, and the service life of the equipment was extended.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NINGXIA TIANDI BENNIU IND GRP
- Filing Date
- 2024-02-02
- Publication Date
- 2026-06-23
AI Technical Summary
The existing scraper conveyor's central trough has insufficient load-bearing capacity under high mining conditions, which easily leads to trough deformation, weld cracking, scraper plate breakage and other failures, affecting the equipment's reliability and service life.
The high-load-bearing central trough structure adopts a composite frame type. By adding a rectangular frame bottom structure to the bottom plate, the stress is distributed to the surrounding area. Combined with wear sensors to detect the wear of the bottom plate, the load-bearing capacity and reliability of the central trough are improved.
It significantly improves the load-bearing capacity and service life of the central tank, reduces stress concentration, extends the maintenance cycle of the equipment, and enhances the overall reliability of the machine.
Smart Images
Figure CN118062490B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coal mine machinery and equipment technology, specifically to a composite frame type high load-bearing central trough and scraper conveyor. Background Technology
[0002] Scraper conveyors are the main transportation equipment in underground coal mining faces, and 80% of their main body is composed of the central trough. As the core component and main part of the scraper conveyor, the reliability of the central trough directly affects the working efficiency and reliability of the scraper conveyor. At present, the central troughs of scraper conveyors in China are mainly divided into cast-welded type and integral casting type. The cast-welded type central trough is made by welding together the baffle trough side, shovel trough side, middle plate and bottom plate. The integral casting type central trough is cast into a whole in one piece. However, whether it is cast-welded or integral casting, the structural form of the central trough is basically the same, that is, it is a combination of baffle trough side, shovel trough side, single-layer middle plate and single-layer bottom plate.
[0003] Installing or replacing the central slot of a coal mining machine underground is an extremely time-consuming and labor-intensive task. Each replacement of the central slot for a single coal face takes approximately 40 days. Surveys show that the replacement frequency of the central slot in large domestic coal mines is currently 2-3 times per year, taking 80-120 days. Improving the service life of the central slot means increasing the effective operating time of the equipment, thereby creating conditions for increasing coal mine output and improving economic efficiency. Therefore, improving the service life of the central slot is of great significance for improving the operating rate of coal mining machines.
[0004] To solve the above-mentioned technical problems, the technical solution of the Chinese utility model patent announcement with patent application number CN200920019382.7 is a middle trough of a coal mining machine, which includes a middle plate and W steel components at both ends. The middle plate is installed and fixed between the upper grooves of the W steel components at both ends. The middle plate and the W steel components at both ends are composed of two parts: basic structural components and wear-resistant functional components. They are assembled into a whole. The wear-resistant functional components are bimetallic composite wear-resistant steel plates.
[0005] However, the above-mentioned existing technologies have the following technical problems: The coal mining machine trough provided by the above solution increases the service life of the trough by adding wear-resistant functional components, but its main structure is still the same as that of the traditional trough. The stress borne by the trough of this structure is relatively concentrated. With the continuous increase in the mining height of the working face in recent years, the hydraulic support and the coal mining machine have also become larger. In the working face with a mining height of 8 meters or more, the thrust of the hydraulic support cylinder increases to more than 160 tons, and the weight of the coal mining machine also increases to more than 180 tons. The load-bearing capacity of the trough with this structure is difficult to adapt. During the process of pushing and pulling the trough, the trough body and bottom plate are prone to deformation, weld cracking, and shovel plate breakage and failure, which seriously affects the overall reliability and service life of the scraper conveyor. Summary of the Invention
[0006] In view of this, it is necessary to provide a composite frame type high load-bearing central trough and scraper conveyor that can disperse the stress borne by the central trough, thereby increasing the overall reliability and service life of the scraper conveyor.
[0007] A composite frame-type high load-bearing central trough includes baffle trough sides, shovel trough sides, a middle plate, and a bottom plate. The inner sides of the baffle trough sides and shovel trough sides are arranged facing each other. The middle plate and the bottom plate are both installed in the middle of the inner sides of the baffle trough sides and shovel trough sides. The bottom plate is installed at the bottom of the inner sides of the baffle trough sides and shovel trough sides. The bottom plate includes a frame plate, two identical support bars, a first connecting plate, and a second connecting plate. The first connecting plate and the second connecting plate are located at both ends of the frame plate, and their ends are fixedly connected to the baffle trough sides and shovel trough sides, respectively. The two support bars are arranged on the bottom surface of the frame plate, and their ends are connected to the baffle trough sides and shovel trough sides, respectively, and are located inside the first connecting plate and the second connecting plate.
[0008] Preferably, the baffle groove is provided with a toothed rail seat, a sliding ear, a first positioning protrusion and a second positioning protrusion. The toothed rail seat is located at the top of the baffle groove; the sliding ear is located on the outside of the baffle groove; the first positioning protrusion is located at the bottom of the inner side of the baffle groove; and the second positioning protrusion is located at the middle of the inner side of the baffle groove.
[0009] Preferably, the spade plate groove is provided with a third positioning protrusion, a fourth positioning protrusion, two dumbbell grooves of the same structure, and two dumbbell pins of the same structure. The third positioning protrusion and the fourth positioning protrusion are both located on the inner side of the spade plate groove and satisfy the following conditions: the third positioning protrusion is at the same height as the first positioning protrusion, and the fourth positioning protrusion is at the same height as the second positioning protrusion; the two dumbbell grooves are both located at the same height on the outer side of the spade plate groove and are arranged in opposite directions at both ends of the spade plate groove; one end of each dumbbell pin is installed in the dumbbell groove, and the other end is installed in the dumbbell groove of the adjacent composite frame high load-bearing middle groove.
[0010] Preferably, the first connecting plate is provided with two drum-shaped pins with the same structure, and the two drum-shaped pins are evenly arranged on the side of the first connecting plate facing away from the frame plate; the second connecting plate is evenly provided with two fixing holes of the same size, and the two fixing holes satisfy the condition that the two drum-shaped pins can be inserted into the two fixing holes of the adjacent composite frame high load-bearing central groove.
[0011] Preferably, the bottom surface of the frame plate is provided with mounting holes, which are adjacent to the side of the middle section of any support bar, and the mounting holes penetrate through the upper and lower surfaces of the frame plate.
[0012] Preferably, the composite frame-type high load-bearing central groove further includes a wear sensor. The wear sensor includes a stainless steel block, a sensor protective cover, a permanent magnet, a stress sensor, a mounting bracket, and a sensor connecting wire. The stainless steel block is welded into the mounting hole, and the top surface of the stainless steel block is flush with the top surface of the frame plate. The sensor protective cover is a shell with only one opening, and the sensor protective cover is fixed to the bottom surface of the frame plate with the opening facing the mounting hole. The stress sensor, permanent magnet, and mounting bracket are all disposed inside the sensor protective cover. The permanent magnet is fixed to the top of the stress sensor, and the bottom of the stress sensor is fixedly connected to the mounting bracket. The mounting bracket is fixed to the bottom surface inside the sensor protective cover. One end of the sensor connecting wire is connected to the stress sensor, and the other end of the sensor connecting wire passes through the side of the baffle groove and is connected to the display device.
[0013] A scraper conveyor includes a scraper conveyor body and several composite frame type high load-bearing central troughs as described above, wherein the composite frame type high load-bearing central troughs are disposed on the inner side of the scraper conveyor body.
[0014] The aforementioned composite frame high-load-bearing central trough includes baffle trough sides, shovel trough sides, a central plate, and a bottom sealing plate. The bottom sealing plate and the central plate are located inside the baffle trough sides and shovel trough sides. The bottom surface of the bottom sealing plate is provided with a composite frame bottom sealing structure composed of two connecting plates and two support bars. By adding a composite frame bottom sealing structure to the bottom of the bottom sealing plate, this invention disperses the stress borne by the composite frame high-load-bearing central trough, effectively improving the load-bearing capacity of the composite frame high-load-bearing central trough. This allows the composite frame high-load-bearing central trough to adapt to the increased pressure as the working face increases, thereby increasing the overall reliability and service life of the scraper conveyor. Attached Figure Description
[0015] Figure 1 This is a top-down oblique view of the composite frame-type high load-bearing central trough of this application.
[0016] Figure 2 This is an oblique upward view of the composite frame-type high load-bearing central channel of this application.
[0017] Figure 3 This is a bottom view of the composite frame-type high load-bearing central trough of this application.
[0018] Figure 4 This is a front perspective view of the composite frame-type high load-bearing central channel of this application.
[0019] Figure 5 This is a simulation result diagram of the deformation of the conventional cast-welded central groove in Embodiment 1 of this application.
[0020] Figure 6 This is a simulation result diagram of the deformation of the composite frame-type high load-bearing central groove in Embodiment 1 of this application.
[0021] Figure 7 This is an equivalent stress simulation result diagram of the conventional cast-welded central groove in Embodiment 1 of this application.
[0022] Figure 8 This is an equivalent stress simulation result diagram of the composite frame-type high load-bearing central trough in Embodiment 1 of this application.
[0023] In the diagram: Composite frame high load-bearing central groove 10, baffle groove side 20, toothed rail seat 21, push lug 22, first positioning protrusion 23, second positioning protrusion 24, shovel groove side 30, third positioning protrusion 31, fourth positioning protrusion 32, dumbbell groove 33, middle plate 40, bottom sealing plate 50, frame plate 51, support bar 52, first connecting plate 53, drum-shaped pin 54, second connecting plate 55, fixing hole 56, wear sensor 60, stainless steel stop block 61, sensor protective cover 62, permanent magnet 63, stress sensor 64, mounting bracket 65, sensor connecting wire 66, alloy steel scraper 70. Detailed Implementation
[0024] The technical solutions and effects of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.
[0025] A composite frame-type high-load-bearing central trough 10 includes baffle trough sides 20, shovel trough sides 30, a central plate 40, and a bottom sealing plate 50. The inner sides of the baffle trough sides 20 and shovel trough sides 30 are directly opposite each other. The central plate 40 and the bottom sealing plate 50 are both installed in the middle of the inner sides of the baffle trough sides 20 and shovel trough sides 30. The bottom sealing plate 50 is installed at the bottom of the inner sides of the baffle trough sides 20 and shovel trough sides 30. The bottom sealing plate 50 includes a frame plate 51, two identical support bars 52, a first connecting plate 53, and a second connecting plate 55. The first connecting plate 53 and the second connecting plate 55 are located at both ends of the frame plate 51, and both ends of the first connecting plate 53 and the second connecting plate 55 are respectively connected to the baffle trough sides. The baffle plate 20 and the shovel plate groove 30 are fixedly connected. Two support bars 52 are set on the bottom surface of the frame plate 51. The two ends of each support bar 52 are respectively connected to the baffle plate groove 20 and the shovel plate groove 30, and are located inside the first connecting plate 53 and the second connecting plate 55. In this invention, the first connecting plate 53, the second connecting plate 55 and the two support bars 52 divide the bottom surface of the bottom plate 50 into three rectangular frames of the same size, so as to evenly distribute the pressure borne by the composite frame type high load-bearing central groove 10 to the surrounding area, thereby improving the load-bearing capacity of the composite frame type high load-bearing central groove 10 and enabling the composite frame type high load-bearing central groove 10 to adapt to the increased pressure as the mining height of the working face increases.
[0026] Furthermore, the baffle groove 20 is provided with a toothed rail seat 21, a sliding ear 22, a first positioning protrusion 23, and a second positioning protrusion 24. The toothed rail seat 21 is located at the top of the baffle groove 20 and is used to install the toothed rail. The sliding ear 22 is located on the outside of the baffle groove 20 and is used to connect with the hydraulic support. The first positioning protrusion 23 is located at the bottom of the inner side of the baffle groove 20 to fix the frame plate 51 to the baffle groove 20. The second positioning protrusion 24 is located at the middle of the inner side of the baffle groove 20 to fix the middle plate 40 to the baffle groove 20.
[0027] Furthermore, the spade plate groove 30 is provided with a third positioning protrusion 31, a fourth positioning protrusion 32, two dumbbell grooves 33 of the same structure, and two dumbbell pins of the same structure. The third positioning protrusion 31 and the fourth positioning protrusion 32 are both located inside the spade plate groove 30. The third positioning protrusion 31 is used to fix the frame plate 51 to the spade plate groove 30, and the fourth positioning protrusion 32 is used to fix the middle plate 40 to the spade plate groove 30. Furthermore, the third positioning protrusion 31 and the first positioning protrusion 23 are at the same height to horizontally fix the frame plate 51; the fourth positioning protrusion 32... The protrusion 32 is at the same height as the second positioning protrusion 24 to horizontally fix the middle plate 40; the two dumbbell slots 33 are both located at the same height on the outside of the shovel plate groove side 30 and are respectively arranged at both ends of the shovel plate groove side 30 in opposite directions to ensure that the dumbbell pins can be arranged horizontally in the dumbbell slots 33 of the two adjacent composite frame high load-bearing middle grooves 10; one end of each dumbbell pin is installed in the dumbbell slot 33 and the other end is installed in the dumbbell slot 33 of the adjacent composite frame high load-bearing middle groove 10 to limit the horizontal angle between the two adjacent composite frame high load-bearing middle grooves 10.
[0028] In this embodiment, the first connecting plate 53 is provided with two identical drum-shaped pins 54, which are evenly arranged on the side of the first connecting plate 53 facing away from the frame plate 51. The second connecting plate 55 is evenly provided with two fixing holes 56 of the same size, and the two fixing holes 56 satisfy the following: the two drum-shaped pins 54 can be inserted into the two fixing holes 56 of the adjacent composite frame high load-bearing central groove 10, so as to limit the vertical angle between the two adjacent composite frame high load-bearing central grooves 10. When the drum-shaped pins 54 are used to connect the two adjacent composite frame high load-bearing central grooves 10, the two adjacent composite frame high load-bearing central grooves 10 can be quickly connected by aligning the drum-shaped pins 54 with the fixing holes 56, thereby improving the installation efficiency of the composite frame high load-bearing central groove 10.
[0029] In this embodiment, by setting a drum-shaped pin 54, the horizontal and vertical angle limits between two adjacent composite frame high load-bearing central grooves 10, which were originally limited by dumbbell pins, are split into horizontal angle limits limited by dumbbell pins and vertical angle limits limited by drum-shaped pins 54. This prevents stress concentration at the dumbbell pins and increases the service life of the dumbbell pins.
[0030] In this embodiment, the bottom surface of the frame plate 51 is provided with a mounting hole, which is adjacent to the side of the middle section of any support bar 52. The mounting hole penetrates the upper and lower surfaces of the frame plate 51 so that the wear sensor 60 installed at the mounting hole is not disturbed by the baffle groove 20 and the scraper groove 30 on both sides of the frame plate 51, so that the stress value detected by the wear sensor 60 is more accurate.
[0031] In this embodiment, the composite frame-type high-load-bearing central groove 10 further includes a wear sensor 60 to detect the wear of the frame plate 51. The wear sensor 60 includes a stainless steel block 61, a sensor protective cover 62, a permanent magnet 63, a stress sensor 64, a mounting bracket 65, and a sensor connection wire 66. The stainless steel block 61 is welded inside the mounting hole, and the top surface of the stainless steel block 61 is flush with the top surface of the frame plate 51 to make the detection results more accurate. The sensor protective cover 62 is a shell with only one opening, for example, a cylindrical shell with only one opening, and the sensor protective cover 62 is positioned so that the opening faces the mounting hole. The stress sensor 64, permanent magnet 63, and mounting bracket 65 are all fixed to the bottom surface of the frame plate 51. The permanent magnet 63 is fixed to the top of the stress sensor 64 so that the stress sensor 64 can detect the tension between the permanent magnet 63 and the alloy steel scraper 70. The bottom end of the stress sensor 64 is fixedly connected to the mounting bracket 65, which is fixed to the bottom surface inside the sensor protective cover 62. One end of the sensor connection line 66 is connected to the stress sensor 64, and the other end of the sensor connection line 66 passes through the baffle groove 20 and is connected to a display device, such as a monitor.
[0032] In this embodiment, an attractive force is generated between the permanent magnet 63 and the alloy steel scraper 70 installed on the scraper conveyor, and this attractive force is detected by the stress sensor 64. The stainless steel stop 61 and the permanent magnet 63 do not generate an attractive force, so they do not interfere with the attractive force detected by the stress sensor 64. When the top surface of the frame plate 51 is worn, the distance between the alloy steel scraper 70 and the permanent magnet 63 decreases, which strengthens the attractive force between them. The value detected by the stress sensor 64 also increases accordingly. The operator can judge the degree of wear of the frame plate 51 by the change in the value detected by the stress sensor 64.
[0033] In this embodiment, the bottom of the baffle groove 20 has a groove for the sensor connection wire 66 to pass through.
[0034] The present invention also provides a scraper conveyor, including a scraper conveyor body and several composite frame high load-bearing central troughs 10 as described above. The composite frame high load-bearing central troughs 10 are disposed on the inner side of the scraper conveyor body and are used for transporting coal.
[0035] In this embodiment, the finite element module integrated into the Solid Edge platform of Siemens PLM Software was used to perform finite element simulation analysis on the traditional cast-welded central trough and the composite frame high-load-bearing central trough 10 according to the parameter loads of the supporting coal mining machine and hydraulic support. The curved surface structure of the upper part of the central trough, which has little impact on the structural strength, was appropriately simplified and removed. The central trough model was meshed using tetrahedral mesh. The total number of meshes for the traditional cast-welded central trough was 471,338, with 2,780,894 mesh nodes. The total number of meshes for the composite frame high-load-bearing central trough was 436,291, with 2,661,375 mesh nodes.
[0036] Based on the thrust of the hydraulic support cylinder, a thrust load is applied to the sliding lug of the middle trough, a pressure load of the coal mining machine is applied to the toothed rail seat and shovel plate of the middle trough, a fixed constraint is applied at the connection of both ends of the middle trough, and a frictional load is applied to the bottom plate and shovel plate of the middle trough. The stress and deformation of the head frame are simulated and analyzed, and the simulation results of the deformation of the traditional cast-welded middle trough are obtained. Figure 5 Equivalent stress simulation results of traditional cast-welded central trench Figure 7 Simulation results of deformation of composite frame high load-bearing central groove 10 Figure 6 Equivalent stress simulation results of composite frame high load-bearing central trough 10 Figure 8 .
[0037] In the figure, the magnitude of deformation and equivalent stress are represented by color, and their values are arranged from largest to smallest as follows: red > orange > yellow > light green > dark green > cyan > light blue > dark blue.
[0038] By comparison Figure 5 and Figure 6 It can be observed that the deformation of the traditional cast-welded central channel is mostly in colors with large values such as red, orange, and yellow, and the entire bottom plate is red; while the deformation of the composite frame high load-bearing central channel 10 is mostly in colors with small values such as dark blue, light blue, and cyan, with only a small portion being red; indicating that the composite frame high load-bearing central channel 10 provided by the present invention can significantly reduce the deformation.
[0039] By comparison Figure 7 and Figure 8It can be observed that the maximum stress in the traditional cast-welded central channel occurs at the tenon of the channel side, the weld of the channel side of the middle plate, the upper edge of the channel side, and the shovel plate; while the maximum stress in the composite frame high load-bearing central channel 10 mainly occurs at the push-out lug of the baffle channel side.
[0040] In summary, the above comparison shows that, compared with the traditional cast-welded central trough, the composite frame high-load-bearing central trough 10 has a more balanced stress distribution, significantly reduced stress concentration areas, and thanks to the frame structure, the trough stiffness is greatly improved, and the deformation at the bottom plate of the central trough is significantly reduced.
[0041] Furthermore, the data shown in Table 1 can be obtained based on the head simulation.
[0042] Table 1
[0043]
[0044] The data shows that, compared with the traditional cast-welded central channel, the composite frame high-load-bearing central channel 10 experiences a 51% reduction in maximum stress; a 52% reduction in maximum deformation; a 70% increase in material yield strength; and an increase in its safety factor from 2.69 to 9.41.
[0045] This invention improves the load-bearing capacity of the composite frame high-load-bearing central trough 10 by adding a composite frame bottom sealing structure composed of rectangular frames to the bottom sealing plate 50, thereby dispersing the stress borne by the central trough. This allows the composite frame high-load-bearing central trough 10 to adapt to the increased pressure as the working face increases. Furthermore, by setting a wear sensor 60, the wear condition of the bottom sealing plate can be detected, and the composite frame high-load-bearing central trough 10 can be repaired in a timely manner.
[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A composite frame-type high load-bearing central trough, characterized in that, The device includes a baffle groove, a shovel groove, a middle plate, and a bottom plate. The inner sides of the baffle groove and the shovel groove are directly opposite each other. The middle plate and the bottom plate are both installed in the middle of the inner sides of the baffle groove and the shovel groove. The bottom plate is installed at the bottom of the inner sides of the baffle groove and the shovel groove. The bottom plate includes a frame plate, two identical support bars, a first connecting plate, and a second connecting plate. The first connecting plate and the second connecting plate are located at both ends of the frame plate, and their ends are fixedly connected to the baffle groove and the shovel groove, respectively. The two support bars are located on the bottom surface of the frame plate, and their ends are connected to the baffle groove and the shovel groove, respectively, and are located inside the first connecting plate and the second connecting plate.
2. The composite frame-type high load-bearing central trough as described in claim 1, characterized in that, The baffle groove is provided with a toothed rail seat, a sliding ear, a first positioning protrusion and a second positioning protrusion. The toothed rail seat is located at the top of the baffle groove; the sliding ear is located on the outside of the baffle groove; the first positioning protrusion is located at the bottom of the inner side of the baffle groove; and the second positioning protrusion is located at the middle of the inner side of the baffle groove.
3. The composite frame-type high load-bearing central trough as described in claim 2, characterized in that, The shovel plate groove is provided with a third positioning protrusion, a fourth positioning protrusion, two dumbbell grooves of the same structure, and two dumbbell pins of the same structure. The third positioning protrusion and the fourth positioning protrusion are both located on the inner side of the shovel plate groove and satisfy the following conditions: the third positioning protrusion is at the same height as the first positioning protrusion, and the fourth positioning protrusion is at the same height as the second positioning protrusion; the two dumbbell grooves are both located at the same height on the outer side of the shovel plate groove and are respectively arranged at both ends of the shovel plate groove in opposite directions; one end of each dumbbell pin is installed in the dumbbell groove, and the other end is installed in the dumbbell groove of the adjacent composite frame high load-bearing middle groove.
4. The composite frame-type high load-bearing central trough as described in claim 1, characterized in that, The first connecting plate is provided with two drum-shaped pins with the same structure, and the two drum-shaped pins are evenly arranged on the side of the first connecting plate facing away from the frame plate; the second connecting plate is evenly provided with two fixing holes of the same size, and the two fixing holes satisfy the condition that the two drum-shaped pins can be inserted into the two fixing holes of the adjacent composite frame high load-bearing central groove.
5. The composite frame-type high load-bearing central trough as described in claim 1, characterized in that, The bottom surface of the frame plate is provided with mounting holes, which are adjacent to the side of the middle section of any support bar and penetrate through the upper and lower surfaces of the frame plate.
6. The composite frame-type high load-bearing central trough as described in claim 5, characterized in that, The composite frame-type high load-bearing central groove also includes a wear sensor. The wear sensor includes a stainless steel block, a sensor protective cover, a permanent magnet, a stress sensor, a mounting bracket, and a sensor connecting wire. The stainless steel block is welded into the mounting hole, and the top surface of the stainless steel block is flush with the top surface of the frame plate. The sensor protective cover is a shell with only one opening, and it is fixed to the bottom surface of the frame plate with the opening facing the mounting hole. The stress sensor, permanent magnet, and mounting bracket are all disposed inside the sensor protective cover. The permanent magnet is fixed to the top of the stress sensor, and the bottom of the stress sensor is fixedly connected to the mounting bracket. The mounting bracket is fixed to the bottom surface inside the sensor protective cover. One end of the sensor connecting wire is connected to the stress sensor, and the other end of the sensor connecting wire passes through the side of the baffle groove and is connected to the display device.
7. A scraper conveyor, characterized in that, It includes a scraper conveyor body and several composite frame high load-bearing central troughs as described in any one of claims 1 to 6, wherein the composite frame high load-bearing central troughs are disposed on the inner side of the scraper conveyor body.