Slurry reverse circulation flushing device for well drilling

Abstract

The invention relates to the technical field of drilling equipment, in particular to a drilling mud reverse circulation flushing device which comprises a drilling cutting separating device, the drilling cutting separating device comprises an outer shell, and the interior of the outer shell is divided into a separating area and a discharging area through a partition plate; a liquid outlet is formed in the position, located in the separation area, of the outer side wall of the outer shell, a drilling cutting separation assembly is arranged in the separation area, and the drilling cutting separation assembly comprises an inner intercepting net. According to the device, the feeding pipe, the inner intercepting net and the outer intercepting net are arranged in a matched mode, the first motor is started, the inner intercepting net and the outer intercepting net rotate in the opposite directions, stronger shearing force is formed in the outer shell, the blocking risk of the filter net is reduced, and the separation efficiency of drilling cuttings is improved. The separating hopper is arranged at the bottom of the drilling cutting separating assembly, the blocking mechanism is arranged in the separating hopper, and the conveying mechanism is arranged below the separating hopper, so that the drilling cutting can be automatically conveyed to the outside through the conveying mechanism, and the labor intensity of workers is relieved.

Description

Technical Field

[0001] The invention relates to the technical field of drilling equipment, in particular to a drilling mud reverse circulation flushing device. Background Art

[0002] In drilling operations, mud plays a vital role. It is not only used to cool the drill bit and carry drill cuttings, but also to maintain the stability of the well wall and prevent formation collapse. The traditional mud circulation system usually adopts a positive circulation method, that is, the mud is injected from the wellhead, flows to the bottom of the well through the inside of the drill pipe, and then carries the drill cuttings back to the ground through the annular space between the drill pipe and the well wall. However, under certain complex geological conditions, such as gas-bearing formations, leaky formations or deep well operations, the positive circulation method may face problems such as mud loss, well wall instability, and low cuttings carrying efficiency. In order to solve these problems, the mud reverse circulation flushing device came into being. The reverse circulation method changes the flow path of the mud, allowing the mud to flow upward from the bottom of the well. Through a specific device structure, it can more effectively carry the drill cuttings back to the ground, while reducing the loss of mud and the instability of the formation.

[0003] However, although the traditional mud reverse circulation flushing device has improved the cuttings carrying efficiency to a certain extent, it still has shortcomings in the cuttings separation link. Most of the cuttings separation devices on the market currently use simple physical sedimentation or screening methods, with low separation efficiency, resulting in excessively high cuttings content in the mud, which not only affects the recycling effect of the mud, but may also cause wear on the drilling equipment and increase operating costs. Summary of the invention

[0004] The object of the present invention is to provide a drilling mud reverse circulation flushing device to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A drilling mud reverse circulation flushing device, comprising:

[0007] The cam is provided with a plurality of camshafts, each of which is provided with a plurality of camshafts, each of which is provided with a plurality of camshafts, each of which is provided with a plurality of camshafts.

[0008] A gravel pump, wherein the gravel pump is connected with a connecting pipe 1 and a connecting pipe 2, and the other end of the connecting pipe 2 is connected with the top end of the feeding pipe;

[0009] A casing is buried in the area where drilling is required, wherein the side wall of the casing located above the ground is connected to a connecting pipe 3, and the other end of the connecting pipe 3 is connected to the drainage port;

[0010] The drill rod is installed on the drilling rig, the bottom end of the drill rod is provided with a drill bit, and the top of the drill rod is connected with the other end of the connecting pipe.

[0011] Preferably, the outer wall of the feeding pipe at the bottom end is provided with two side openings, and the bottom end of the feeding pipe is fixedly connected to a limiting plate.

[0012] Further, the blocking mechanism comprises:

[0013] The inner wall of the movable ring is slidably connected with the outer wall of the side opening;

[0014] There are four fixed rods, one end of which is fixedly connected to the outer wall of the moving ring;

[0015] A connecting column is arranged below the moving ring, and an outer wall of the connecting column is fixedly connected to the other ends of the four fixing rods;

[0016] A plug plate, the top end of which is fixedly connected to the bottom end of the connecting column;

[0017] A fixing ring is sleeved on the feeding pipe at the top surface of the outer shell;

[0018] Two electric telescopic rods are provided, the top ends of the two electric telescopic rods are fixedly connected to the bottom surface of the fixing ring, the outer walls of the two electric telescopic rods are plugged into the top surface of the outer shell, and the output ends of the two electric telescopic rods extend into the interior of the outer shell and are fixedly connected to the two fixing rods respectively;

[0019] Two support rods are provided, the top ends of the two support rods are fixedly connected to the bottom surface of the fixing ring, and the bottom ends of the two support rods are fixedly connected to the top surface of the outer shell.

[0020] Furthermore, the outer wall of the inner interception net is fixedly connected with an outer gear ring.

[0021] Furthermore, an inner gear ring is fixedly connected to the inner wall of the outer interception net.

[0022] Furthermore, the inner top surface of the outer shell is symmetrically rotatably connected with a rotating rod 1 and a rotating rod 2, the bottom ends of the rotating rod 1 and the rotating rod 2 are respectively fixedly connected with a gear 1 and a gear 2, and the gear 1 and the gear 2 are both meshed with the inner gear ring and the outer gear ring for transmission.

[0023] Furthermore, a motor 1 is fixedly connected to the top surface of the outer shell, and a motor shaft of the motor 1 passes through the top surface of the outer shell and is transmission-connected to the top end of the rotating rod 1.

[0024] Furthermore, the aperture of the inner interception net is larger than the aperture of the outer interception net.

[0025] Furthermore, the aperture of the separation bucket is the same as the aperture of the outer interception net.

[0026] Furthermore, a conveying mechanism is arranged in the blanking area of ​​the outer shell, a square groove is opened on the outer wall of the outer shell at the blanking area, the conveying mechanism includes a mounting frame, the outer wall of the mounting frame is inserted into the square groove, an electric conveyor belt is installed between the inner walls of the mounting frame, the outer side wall of the mounting frame is fixedly connected to a second motor, the motor shaft of the second motor is drivingly connected to the driving shaft of the electric conveyor belt, and the mounting frame extends to the bottom surface outside the outer shell and is fixedly connected to two second supporting legs.

[0027] The present invention also provides an operating method of a drilling mud reverse circulation flushing device, which specifically comprises the following steps:

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The outer gear is meshed with the inner gear and the outer gear is meshed with the inner gear and the outer gear is meshed with the inner gear and the outer gear is meshed with the inner gear and the outer gear, so that the inner gear and the outer gear rotate in the opposite direction, so that a stronger shear force is formed inside the outer gear, which not only reduces the risk of filter blockage, but also improves the separation efficiency of drill cuttings, reduces the solid content in mud, and improves the reuse efficiency of mud.

[0030] 2. A separation bucket is provided at the bottom of the drill cuttings separation component, a sealing mechanism is sleeved on the outer wall of the feed pipe, and a conveying mechanism is provided below the separation bucket, so that the two electric telescopic rods can be controlled to extend to drive the plug plate to move downward, thereby sealing the bottom of the separation bucket and forming a separation chamber between the drill cuttings separation component and the separation bucket, thereby improving the separation efficiency. The separated drill cuttings are accumulated at the bottom of the separation bucket due to their weight, and the electric telescopic rods are controlled to contract to raise the plug plate so that the plug plate no longer blocks the separation bucket, thereby allowing the drill cuttings to fall through the bottom of the separation bucket into the conveying mechanism and be transported to the outside, thereby reducing the pollution of the drill cuttings to the environment and alleviating the labor intensity of the workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the overall structure of a drilling mud reverse circulation flushing device of the present invention;

[0032] Figure 2 It is a schematic structural diagram of the drill cuttings separation device in the present invention;

[0033] Figure 3 It is a schematic diagram of the cross-sectional structure of the drill cuttings separation device in the present invention;

[0034] Figure 4 It is a schematic diagram of the structure of the drill cuttings separation assembly in the present invention;

[0035] Figure 5 It is a schematic diagram of the separation bucket structure in the present invention;

[0036] Figure 6 It is a schematic diagram of the structure of the feeding pipe in the present invention;

[0037] Figure 7 It is a schematic diagram of the structure of the blocking mechanism in the present invention.

[0038] In the figure: 100, cuttings separation device; 110, outer shell; 111, support leg 1; 112, drain port; 113, partition plate; 114, motor 1; 120, cuttings separation assembly; 121, inner interception net; 1211, outer gear ring; 122, outer interception net; 1221, inner gear ring; 123, rotating rod 1; 1231, gear 1; 124, rotating rod 2; 1241, gear 2; 130, separation bucket; 1301, annular groove 1; 131, connecting rod; 132, ring; 1321, annular groove 2; 140, Feed pipe; 141, side opening; 142, limit plate; 150, blocking mechanism; 151, moving ring; 152, fixed rod; 153, connecting column; 154, plug plate; 155, fixed ring; 156, electric telescopic rod; 157, support rod; 160, conveying mechanism; 161, mounting frame; 162, electric conveyor belt; 163, motor 2; 164, supporting leg 2; 200, sand and gravel pump; 210, connecting pipe 1; 220, connecting pipe 2; 300, casing; 310, connecting pipe 3; 400, drill pipe; 410, drill bit. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] See also Figure 1-7In an embodiment of the present invention, a drilling mud reverse circulation flushing device includes a cuttings separation device 100, a sand pump 200, a casing 300 and a drill pipe 400. The cuttings separation device 100 includes an outer shell 110. The interior of the outer shell 110 is divided into a separation area and a material drop area by a partition plate 113. The outer wall of the outer shell 110 is provided with a drain port 112 at the location of the separation area. The separation area is provided with a cuttings separation component 120. The cuttings separation component 120 includes The inner interception net 121 includes an outer interception net 122 disposed on the periphery of the inner interception net 121. The top ends of the inner interception net 121 and the outer interception net 122 are rotatably connected to the inner top surface of the outer shell 110. A separation bucket 130 is disposed below the cuttings separation assembly 120. The bottom end of the separation bucket 130 is fixedly connected to the top surface of the partition plate 113. The top surface of the partition plate 113 is provided with a circular notch corresponding to the bottom end of the separation bucket 130. The inner side wall of the separation bucket 130 is connected to the inner top surface of the outer shell 110 by four connecting rods 131. A circular ring 132 is fixedly connected, and the tops of the separation bucket 130 and the circular ring 132 are provided with an annular groove 1301 and an annular groove 2 1321. The bottom ends of the outer interception net 122 and the inner interception net 121 are respectively plugged and rotated with the annular groove 1301 and the annular groove 2 1321. The top surface of the outer shell 110 is penetrated and plugged with a feeding pipe 140. The interior of the separation bucket 130 is provided with a blocking mechanism 150. The bottom surface of the outer shell 110 is fixedly connected with a supporting leg 111. The sand and gravel pump 200 A connecting pipe 1 210 and a connecting pipe 2 220 are connected, the other end of the connecting pipe 2 220 is connected to the top of the feed pipe 140, the casing 300 is buried in the area where drilling is required, and the side wall of the casing 300 located above the ground is connected to a connecting pipe 310, the other end of the connecting pipe 310 is connected to the drain port 112, a drill rod 400 is installed on the drilling rig, a drill bit 410 is provided at the bottom end of the drill rod 400, and the top of the drill rod 400 is connected to the other end of the connecting pipe 1 210.

[0041] Specifically, the casing 300 is buried in the desired drilling area, and the connecting pipe 310 is connected to the casing 300 and the drainage port 112, the connecting pipe 1 210 is connected to the drill pipe 400 and the sand and gravel pump 200, and the connecting pipe 220 is connected to the sand and gravel pump 200 and the top of the feed pipe 140. When the drilling rig controls the drill bit 410 to perform drilling operations, the sand and gravel pump 200 extracts the drill cuttings and mud mixture in the borehole through the connecting pipe 1 210 along the hole at the bottom of the drill bit 410 and transports it to the drill cuttings separation device 100. The mud and drill cuttings mixture first enters the feed pipe 140. The inner and outer interception nets 121 and 122 separate the mud from the drill cuttings. After being intercepted, the drill cuttings accumulate at the bottom of the separation bucket 130 due to gravity. The separation bucket 130 is an inverted cone, so that the intercepted drill cuttings can be more easily gathered at the bottom. The sealing mechanism 150 seals the bottom of the separation bucket 130, so that the drill cuttings are temporarily retained in the separation bucket 130. The mud continues to be injected into the borehole through the outer interception net 122 along the drain port 112 and the connecting pipe three 310 for circulation.

[0042] Embodiment 1

[0043] like Figure 3-6 As shown, in this embodiment, the outer wall of the feeding tube 140 at the bottom is provided with two side openings 141, the bottom end of the feeding tube 140 is fixedly connected to the limiting plate 142, the outer wall of the inner intercepting net 121 is fixedly connected to the outer gear ring 1211, the inner wall of the outer intercepting net 122 is fixedly connected to the inner gear ring 1221, the inner top surface of the outer shell 110 is symmetrically rotatably connected to the rotating rod 123 and the rotating rod 2 124, and the bottom ends of the rotating rod 123 and the rotating rod 2 124 are respectively fixedly connected to It is connected to gear 1231 and gear 2 1241, which are both meshed with the inner gear ring 1221 and the outer gear ring 1211 for transmission. The top surface of the outer shell 110 is fixedly connected to a motor 114, and the motor shaft of the motor 114 passes through the top surface of the outer shell 110 and is transmission-connected to the top of the rotating rod 123. The aperture of the inner intercepting net 121 is larger than the aperture of the outer intercepting net 122, and the aperture of the separation bucket 130 is the same as the aperture of the outer intercepting net 122.

[0044] In this embodiment, the outer wall of the bottom end of the feed pipe 140 is symmetrically provided with two side openings 141. After the mud and drill cuttings mixture enters the feed pipe 140, it will be sprayed out from the side openings 141, increasing the contact area between the mixture and the inner interception net 121. The aperture of the inner interception net 121 is larger than the aperture of the outer interception net 122. The inner interception net 121 preferably intercepts the larger drill cuttings in the mud and drill cuttings mixture. The outer interception net 122 located outside the inner interception net 121 is used to further filter small pieces of solid drill cuttings, thereby improving the purity of the mud and starting the motor 114. The motor shaft of motor 114 is transmitted to rotating rod 123, so that gear 1231 is meshed with outer gear ring 1211 and inner gear ring 1221 for transmission, so that inner interception net 121 and outer interception net 122 rotate in opposite directions, which helps to form a stronger shear force and increase the contact frequency between the drill cuttings and the two, thereby enhancing the separation effect. The intercepted drill cuttings will gradually accumulate in separation bucket 130. The aperture of separation bucket 130 is the same as or smaller than the aperture of outer interception net 122, and is mainly used to reduce the liquid content in the drill cuttings.

[0045] like Figure 7 As shown, in this embodiment, the blocking mechanism 150 includes a moving ring 151 and a fixed ring 155. The inner wall of the moving ring 151 is slidably sleeved with the outer wall of the side opening 141. The outer wall of the moving ring 151 is fixedly connected with four fixing rods 152 at equal angles. The bottom ends of the four fixing rods 152 are fixedly connected with connecting columns 153. The bottom ends of the connecting columns 153 are fixedly connected with a plug plate 154. The fixing ring 155 is sleeved on the position of the feeding tube 140 located on the top surface of the outer shell 110. The bottom of the fixing ring 155 is fixedly connected with the bottom of the fixing ring 155. Two electric telescopic rods 156 are fixedly connected to the surface, the outer walls of the two electric telescopic rods 156 are plugged into the top surface of the outer shell 110, the output ends of the two electric telescopic rods 156 extend into the interior of the outer shell 110 and are fixedly connected to the two fixing rods 152 respectively, and the bottom surface of the fixing ring 155 is fixedly connected to two support rods 157, the top ends of the two support rods 157 are fixedly connected to the bottom surface of the fixing ring 155, and the bottom ends of the two support rods 157 are fixedly connected to the top surface of the outer shell 110.

[0046] During specific implementation, under normal circumstances, the two electric telescopic rods 156 are extended, so that the moving ring 151 slides downward along the outer wall of the feeding pipe 140, and the plug plate 154 blocks the bottom of the separation bucket 130, so that the intercepted drill cuttings remain in the separation bucket 130. When the drill cuttings inside the separation bucket 130 reach a certain amount and need to be cleaned, the two electric telescopic rods 156 are controlled to retract, and the electric telescopic rods 156 drive the moving ring 151 to move upward along the outer wall of the feeding pipe 140. The moving ring 151 is connected to the connecting column 153 through the fixed rod 152, so that the plug plate 154 is driven to move upward. Since the shape of the separation bucket 130 is an inverted cone, that is, it is wide at the top and narrow at the bottom, when the plug plate 154 moves upward, the plug plate 154 no longer contacts the inner wall of the separation bucket 130, and a gap is formed. The plug plate 154 is conical, so that after the plug plate 154 moves upward, the drill cuttings inside the separation bucket 130 will fall from the bottom of the separation bucket 130 to the dropping area below it.

[0047] like Figure 2-3 As shown, in the present embodiment, a conveying mechanism 160 is arranged in the blanking area of ​​the outer shell 110, and a square groove is opened on the outer wall of the outer shell 110 at the location of the blanking area, and the conveying mechanism 160 includes a mounting frame 161, and the outer wall of the mounting frame 161 is inserted through the square groove, and an electric conveyor belt 162 is installed between the inner walls of the mounting frame 161, and the outer wall of the mounting frame 161 is fixedly connected to a motor 163, and the motor shaft of the motor 163 is drivingly connected to the driving shaft of the electric conveyor belt 162, and the mounting frame 161 extends to the bottom surface outside the outer shell 110 and is fixedly connected to two supporting legs 164.

[0048] In specific implementation, an electric conveyor belt 162 is arranged just below the material dropping area. After the drill cuttings fall out from the bottom of the separation bucket 130 , they will accumulate on the electric conveyor belt 162 . Starting the motor 2 163 can enable the electric conveyor belt 162 to transport the drill cuttings to the outside of the outer shell 110 .

[0049] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0050] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A drilling mud reverse circulation flushing device, characterized in that: include: A drill cuttings separation device (100) comprises an outer shell (110), the interior of the outer shell (110) is divided into a separation area and a material dropping area by a partition plate (113), the outer wall of the outer shell (110) is provided with a drain port (112) at the location of the separation area, a drill cuttings separation assembly (120) is provided in the separation area, the drill cuttings separation assembly (120) comprises an inner interception net (121), an outer interception net (122) is provided on the periphery of the inner interception net (121), the top ends of the inner interception net (121) and the outer interception net (122) are both rotatably connected to the inner top surface of the outer shell (110), a separation bucket (130) is provided below the drill cuttings separation assembly (120), the bottom end of the separation bucket (130) is connected to the partition plate (113), and the bottom end of the separation bucket (130) is connected to the partition plate (113). The outer shell (110) is fixedly connected to the top surface of the outer shell (110), the top surface of the partition plate (113) is provided with a circular notch corresponding to the bottom end of the separation bucket (130), the inner side wall of the separation bucket (130) is fixedly connected with a circular ring (132) through four connecting rods (131), the tops of the separation bucket (130) and the circular ring (132) are both provided with an annular groove 1 (1301) and an annular groove 2 (1321), the bottom ends of the outer interception net (122) and the inner interception net (121) are respectively plugged and rotated with the annular groove 1 (1301) and the annular groove 2 (1321), the top surface of the outer shell (110) is penetrated and plugged with a feeding pipe (140), the interior of the separation bucket (130) is provided with a blocking mechanism (150), and the bottom surface of the outer shell (110) is fixedly connected with a supporting leg 1 (111); A gravel pump (200), the gravel pump (200) is connected to a connecting pipe 1 (210) and a connecting pipe 2 (220), and the other end of the connecting pipe 2 (220) is connected to the top end of the feeding pipe (140); The casing (300) is buried in the area where the drilling is required, and the side wall of the casing (300) located above the ground is connected to a connecting pipe (310), and the other end of the connecting pipe (310) is connected to the drainage port (112); The drill rod (400) is installed on the drilling rig. The bottom end of the drill rod (400) is provided with a drill bit (410). The top of the drill rod (400) is connected to the other end of the connecting pipe 1 (210).

2. The drilling mud reverse circulation flushing device according to claim 1, characterized in that: The outer wall of the feeding pipe (140) at the bottom is provided with two side openings (141), and the bottom end of the feeding pipe (140) is fixedly connected to a limiting plate (142).

3. The drilling mud reverse circulation flushing device according to claim 1, characterized in that: The blocking mechanism (150) comprises: The inner wall of the movable ring (151) is slidably sleeved with the outer wall of the side opening (141); Four fixed rods (152) are provided, one end of each of which is fixedly connected to the outer wall of the movable ring (151); A connecting column (153) is arranged below the moving ring (151), and an outer wall of the connecting column (153) is fixedly connected to the other ends of the four fixing rods (152); A plug plate (154), the top end of which is fixedly connected to the bottom end of the connecting column (153); A fixing ring (155) is sleeved on the feeding tube (140) at a position on the top surface of the outer shell (110); Two electric telescopic rods (156) are provided, the top ends of the two electric telescopic rods (156) are fixedly connected to the bottom surface of the fixing ring (155), the outer walls of the two electric telescopic rods (156) are plugged into the top surface of the outer shell (110), and the output ends of the two electric telescopic rods (156) extend into the interior of the outer shell (110) and are fixedly connected to the two fixing rods (152) respectively; Two support rods (157) are provided, the top ends of the two support rods (157) are fixedly connected to the bottom surface of the fixing ring (155), and the bottom ends of the two support rods (157) are fixedly connected to the top surface of the outer shell (110).

4. The drilling mud reverse circulation flushing device according to claim 1, characterized in that: The outer wall of the inner interception net (121) is fixedly connected with an outer gear ring (1211).

5. The drilling mud reverse circulation flushing device according to claim 1, characterized in that: An inner gear ring (1221) is fixedly connected to the inner wall of the outer interception net (122).

6. The drilling mud reverse circulation flushing device according to claim 1, characterized in that: The inner top surface of the outer shell (110) is symmetrically rotatably connected to a rotating rod 1 (123) and a rotating rod 2 (124); the bottom ends of the rotating rod 1 (123) and the rotating rod 2 (124) are respectively fixedly connected to a gear 1 (1231) and a gear 2 (1241); the gear 1 (1231) and the gear 2 (1241) are both meshed with the inner gear ring (1221) and the outer gear ring (1211) for transmission.

7. The drilling mud reverse circulation flushing device according to claim 1, characterized in that: The top surface of the outer shell (110) is fixedly connected to a motor 1 (114), and the motor shaft of the motor 1 (114) passes through the top surface of the outer shell (110) and is transmission-connected to the top end of the rotating rod 1 (123).

8. The drilling mud reverse circulation flushing device according to claim 1, characterized in that: The aperture of the inner interception net (121) is larger than the aperture of the outer interception net (122).

9. The drilling mud reverse circulation flushing device according to claim 1, characterized in that: The aperture of the separation bucket (130) is the same as the aperture of the outer interception net (122).

10. The drilling mud reverse circulation flushing device according to claim 1, characterized in that: A conveying mechanism (160) is arranged in the blanking area of ​​the outer shell (110); a square groove is provided on the outer wall of the outer shell (110) at the location of the blanking area; the conveying mechanism (160) comprises a mounting frame (161); the outer wall of the mounting frame (161) is inserted into and penetrated by the square groove; an electric conveying belt (162) is installed between the inner walls of the mounting frame (161); a second motor (163) is fixedly connected to the outer wall of the mounting frame (161); a motor shaft of the second motor (163) is drivingly connected to a driving shaft of the electric conveying belt (162); and the mounting frame (161) extends to the bottom surface outside the outer shell (110) and is fixedly connected to two second supporting legs (164).

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