A grinding device and a grinding method for marine ladder pipe

Abstract

A grinding device and grinding method for ship ladder pipes, comprising a vertical plate and a transmission wheel, wherein an outer grinder and an inner grinder are arranged on the inner side of the transmission wheel, wherein the outer grinder comprises a plurality of groups of outer grinding brushes and a plurality of groups of outer magnetic blocks, wherein the outer grinding brushes and the outer magnetic blocks are both distributed on the outer side of the pipe, and the inner grinder comprises a plurality of groups of inner grinding brushes and a plurality of groups of inner magnetic blocks, wherein the inner grinding brushes and the inner magnetic blocks are both distributed on the inner side of the pipe, and the outer magnetic blocks and the inner magnetic blocks attract each other, so that the inner grinder on the inner side of the pipe can rotate with the outer grinder, and when the transmission wheel rotates, the outer grinder can grind the outer wall of the pipe; under the mutual attraction of the magnetic blocks installed between the two groups of grinders, the grinder on the inner side of the pipe grinds the inner wall of the pipe, thereby realizing synchronous grinding of the inner and outer walls of the pipe; and the inner grinder does not require a separate power drive, has a relatively simple structure, and can adapt to straight pipes or curved pipes.

Description

Technical Field

[0001] The invention belongs to the technical field of pipe processing, and in particular relates to a grinding device and a grinding method for a marine ladder pipe. Background Art

[0002] Stainless steel marine ladder is an important safety facility on board a ship. Its quality and performance are directly related to the safety of the crew. It is mainly made of high-quality stainless steel materials, has strong corrosion resistance, can resist the erosion of seawater, salt spray and other harsh environments, and maintain beauty and durability for a long time.

[0003] During the processing of marine ladders, it is necessary to bend the pipe according to the shape of the ladder, and then grind the pipe fittings to facilitate the subsequent surface treatment of the pipe and enhance the corrosion resistance and aesthetics of the pipe. At present, the grinding of the outer wall and the inner wall of the pipe are carried out separately, so the processing steps need to be divided into two steps, and two sets of different processing equipment are required, resulting in low processing efficiency of the process. Therefore, there is an urgent need for a device that can grind the inner and outer walls of the pipe at the same time. Summary of the invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention creatively adopts a grinding device and a grinding method for marine ladder pipes to solve the problems raised in the above background technology.

[0005] The technical solution adopted is as follows: The embodiment of the present invention proposes a grinding device for marine ladder pipes, comprising:

[0006] A vertical plate, on which a transmission wheel is rotatably mounted;

[0007] A driving wheel, rotatably mounted on the vertical plate and capable of driving the transmission wheel disc to rotate;

[0008] Among them, an external grinder and an internal grinder are provided on the inner side of the transmission wheel, and the external grinder is fixed on the inner wall of the transmission wheel. The external grinder includes multiple groups of external grinding brushes and multiple groups of external magnetic blocks, and the external grinding brushes and external magnetic blocks are distributed on the outside of the pipe. The internal grinder includes multiple groups of internal grinding brushes and multiple groups of internal magnetic blocks, and the internal grinding brushes and internal magnetic blocks are distributed on the inside of the pipe. The angles between any two adjacent groups of the external magnetic blocks and any two adjacent groups of the internal magnetic blocks are the same, and the external magnetic blocks and the internal magnetic blocks attract each other, so that the internal grinder on the inside of the pipe can rotate with the external grinder.

[0009] Furthermore, the inner grinder further comprises a disk shell, the inner grinding brush and the inner magnetic block are centrally symmetrically distributed on the peripheral outer wall of the disk shell, and along the circumferential direction, the inner grinding brush and the inner magnetic block are alternately distributed;

[0010] A chamber is provided inside the disk shell, an exhaust hole connected to the chamber is provided in the middle of one side of the disk shell, an air pipe is fixedly installed on the disk shell, one end of the air pipe is connected to the exhaust hole, and the other end is connected to a negative pressure device.

[0011] Further, the inner grinding brush comprises:

[0012] A brush seat is slidably mounted in the disk housing along a radial direction;

[0013] A brush, fixedly mounted on the brush holder;

[0014] A spring is fixedly installed between the brush seat and the disc shell, so that the brush seat has elastic potential energy radially outward;

[0015] Wherein, a through hole is provided on the brush seat corresponding to the brush, and the through hole is communicated with the chamber.

[0016] Furthermore, the inner magnetic block includes a magnet seat fixed on the outer wall of the disk shell and a magnet installed on the magnet seat, the end of the magnet seat is provided with a groove for accommodating the magnet, the magnet is fixed in the groove, and the height of the magnet is smaller than the height of the groove, so that when the end face of the magnet seat contacts the tube, there is a gap between the magnet and the tube.

[0017] Furthermore, the height of the gap is set to 1mm-2mm.

[0018] Furthermore, the outer grinding brush, the outer magnetic block, the inner grinding brush and the inner magnetic block are all arranged in three groups, the angle between any two adjacent outer grinding brushes is 120°, the angle between the outer magnetic block and the outer grinding brush is 60°, the angle between any two adjacent inner magnetic blocks is 120°, and the angle between the inner magnetic block and the inner grinding brush is 60°;

[0019] The contact surfaces of the outer grinding brush, the inner grinding brush and the tube are respectively the first grinding surface and the second grinding surface, the distance between the first grinding surface and the second grinding surface is set to the thickness of the tube, and the distance between the end surface of the outer magnetic block and the end surface of the inner magnetic block is greater than the thickness of the tube.

[0020] Furthermore, an air guide ring is fixedly provided on the vertical plate corresponding to the external grinder, an annular air cavity is provided around the outer side of the air guide ring, a plurality of evenly distributed air guide holes are provided on the surface of the air guide ring, the air guide holes are connected with the annular air cavity, a pipe joint connected with the annular air cavity is fixedly provided on the vertical plate, and the pipe joint is connected to an external negative pressure device.

[0021] Furthermore, the transmission wheel includes a wheel shell and a transmission gear plate rotatably installed inside the wheel shell, and a single-side surface of the transmission gear plate is provided with a first clamping plate and a second clamping plate that can move in a radial direction, and the surface of the transmission gear plate is provided with spiral teeth that mesh with the first clamping plate and the second clamping plate for transmission, and when the transmission gear plate rotates, the first clamping plate and the second clamping plate are driven to move synchronously in the radial direction.

[0022] Furthermore, the number of the first clamping plates corresponds to the number of the external magnetic blocks, and the external magnetic blocks are clamped at the ends of the first clamping plates. The number of the second clamping plates corresponds to the number of the external grinding brushes, and the second clamping plates are clamped at the ends of the external grinding brushes.

[0023] The embodiment of the present invention provides a method for grinding a marine ladder pipe, using the above-mentioned marine ladder pipe grinding device, comprising the following steps:

[0024] Selection: According to the diameter and thickness of the pipe, select the outer grinder and the inner grinder that match it, so that the outer grinding brush and the inner grinding brush can fit the outer wall and the inner wall of the pipe at the same time;

[0025] Installation: install the inner grinder on the inner side of the end of the pipe, and make the inner grinding brush fit the inner wall of the pipe. Hold the pipe, place the end with the inner grinder on the inner side of the outer grinder, make the outer grinding brush fit the outer wall of the pipe, and align the outer magnetic block and the inner magnetic block in the radial direction.

[0026] Grinding: Turn on the switch so that the transmission wheel is driven to rotate by the driving wheel, push the pipe by hand, and let the pipe slowly pass through the outer grinder and the inner grinder until the surface of the pipe is completely ground;

[0027] Dust removal: When the grinding step is started, the negative pressure device is started, and the debris generated by the external grinder can enter the annular air cavity through the air guide holes on the surface of the air guide ring and be sucked out by the negative pressure device. The debris generated by the internal grinder can enter the chamber through the through hole and be sucked out by the negative pressure device.

[0028] The beneficial effects achieved by the present invention using the above structure are as follows:

[0029] The present invention arranges two groups of grinders on the inner and outer sides of the pipe, wherein the outer grinder is fixed on a driving wheel, and the driving wheel can be started to rotate by a motor. When the driving wheel rotates, the outer grinder can grind the outer wall of the pipe; under the mutual attraction of magnetic blocks installed between the two groups of grinders, the grinder on the inner side of the pipe grinds the inner wall of the pipe, thereby realizing synchronous grinding of the inner and outer walls of the pipe; and the inner grinder does not need a separate power drive, has a relatively simple structure, and can adapt to straight pipes or curved pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the three-dimensional structure of a grinding device for marine ladder pipes proposed in an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of a three-dimensional structure of one side of a transmission wheel in a grinding device for marine ladder pipes proposed in an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of the structure inside the vertical plate is provided for an embodiment of the present invention;

[0033] Figure 4 A schematic diagram of the internal structure of a transmission wheel is provided for an embodiment of the present invention;

[0034] Figure 5 A schematic diagram of the three-dimensional structure of an internal grinder is provided for an embodiment of the present invention;

[0035] Figure 6 A schematic diagram of the internal structure of an internal grinder is provided for an embodiment of the present invention;

[0036] Among them, 10, vertical plate; 100, annular air cavity; 101, air guide ring; 102, air guide hole; 11, bottom plate; 12, pipe joint; 20, external grinder; 21, external grinding brush; 22, external magnetic block; 30, internal grinder; 31, disk shell; 310, exhaust hole; 311, chamber; 32, internal grinding brush; 320, through hole; 321, brush seat; 322, brush; 323, spring; 33, internal magnetic block; 331, magnet seat; 332, magnet; 40, air pipe; 50, transmission wheel; 51, wheel shell; 52, transmission gear plate; 521, spiral teeth; 53, first clamping plate; 54, second clamping plate; 60, driving wheel; 61, motor.

[0037] The accompanying drawings are used to provide further understanding of the embodiments and constitute a part of the specification. They are used for explanation together with the embodiments and do not constitute a limitation of the embodiments. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection.

[0039] In the description of the embodiments, it should be understood that terms such as "up", "down", "front", "back", "left", "right", "top", "bottom", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the embodiments.

[0040] like Figure 1 and Figure 2 As shown, in an embodiment of the present invention, a grinding device for marine ladder pipes is provided, aiming to improve the grinding speed of the pipes. The device mainly comprises a vertical plate 10 and a transmission wheel 50 and a driving wheel 60 installed on the vertical plate 10.

[0041] Among them, the vertical plate 10 is made of one or a combination of aluminum alloy, stainless steel or plastic materials to support the rectangular plate body. A circular groove is reserved in the middle part for installing the transmission wheel 50. A bearing is installed at the connection between the transmission wheel 50 and the vertical plate 10 to reduce rotational friction, and a base plate 11 is fixed at the bottom of the vertical plate 10 to facilitate the installation of the vertical plate 10 on the workbench.

[0042] Furthermore, a motor 61 is fixedly installed inside the vertical plate 10, and the output end of the motor 61 is fixedly connected to the driving wheel 60. The driving wheel 60 is located on the outer periphery of the transmission wheel 50 and can drive the transmission wheel 50 to rotate. In some embodiments, the driving wheel 60 can be a gear or a rubber wheel, which can drive the transmission wheel 50 to rotate under the drive of the motor 61.

[0043] Furthermore, in order to grind the inner and outer walls of the pipe at the same time, an outer grinder 20 and an inner grinder 30 are provided on the inner side of the driving wheel 50 .

[0044] The external grinder 20 is fixed on the inner wall of the transmission wheel 50, and includes multiple groups of external grinding brushes 21 and multiple groups of external magnetic blocks 22. The external grinding brushes 21 and the external magnetic blocks 22 are all distributed on the outer side of the pipe. In this way, when the transmission wheel 50 rotates, the external grinder 20 on the inner wall of the transmission wheel 50 will rotate synchronously with the transmission wheel 50, and use the external grinding brushes 21 attached to the outer side of the pipe to grind the outer wall of the pipe.

[0045] The inner grinder 30 includes multiple groups of inner grinding brushes 32 and multiple groups of inner magnetic blocks 33. The inner grinding brushes 32 and the inner magnetic blocks 33 are all distributed on the inner side of the pipe, and the angles between any two adjacent groups of outer magnetic blocks 22 and any two adjacent groups of inner magnetic blocks 33 are the same, and the outer magnetic blocks 22 and the inner magnetic blocks 33 attract each other, so that the inner grinder 30 on the inner side of the pipe can rotate with the outer grinder 20. In this way, when the outer magnetic block 22 rotates with the driving wheel 50, the inner magnetic block 33, which is attracted to the outer magnetic block 22, will also move with the outer magnetic block 22 under the action of magnetic attraction, so that the inner grinder 30 rotates inside the pipe, and the inner grinding brush 32 grinds the inner wall of the pipe by virtue of the rotation.

[0046] In summary, two groups of grinders are arranged on the inner and outer sides of the pipe, wherein the outer grinder is fixed on the driving wheel 50, and the driving wheel 50 can be started to rotate by the motor 61. When the driving wheel 50 rotates, the outer grinder can not only grind the outer wall of the pipe, but also the magnetic blocks installed between the two groups of grinders attract each other, so that the grinder on the inner side of the pipe grinds the inner wall of the pipe, thereby realizing synchronous grinding of the inner and outer walls of the pipe. Moreover, the inner grinder 30 does not require a separate power drive, and the structure is relatively simple, which can adapt to straight pipes or curved pipes.

[0047] like Figure 5 and Figure 6 As shown, the internal grinder 30 further includes a disk shell 31, and the internal grinding brushes 32 and the internal magnetic blocks 33 are centrally symmetrically distributed on the peripheral outer wall of the disk shell 31, and along the circumferential direction, the internal grinding brushes 32 and the internal magnetic blocks 33 are alternately distributed.

[0048] Among them, the inner grinding brush 32 includes a brush seat 321, a brush 322 and a spring 323. The brush seat 321 is slidably installed in the disk shell 31 along the radial direction, the brush 322 is fixedly installed on the brush seat 321, and the spring 323 is fixedly installed between the brush seat 321 and the disk shell 31, so that the brush seat 321 has elastic potential energy radially outward.

[0049] In some embodiments, the brush holder 321 is constructed of stainless steel or aluminum alloy into a "J"-shaped structure, and the brush 322 is arranged on the protruding part of the upper end of the brush holder 321, wherein the brush 322 includes multiple groups of bristles, and the arrangement density of the bristles and the hardness of the bristles can be set to be different, so that each group of internal grinding brushes 32 has different grinding effects, so that after multiple groups of internal grinding brushes 32 grind the inner wall of the pipe together, the grinding effect is better, and the two supporting legs of the brush holder 321 play a limiting role in the disk shell 31, which can prevent the brush holder 321 from falling out of the disk shell 31, and the two supporting legs are connected to the spring 323, which can provide elastic support for the brush holder 321, so that the brush 322 can always fit on the pipe wall for grinding.

[0050] Furthermore, the inner magnetic block 33 includes a magnet seat 331 fixed on the outer wall of the disk shell 31 and a magnet 332 installed on the magnet seat 331. The end of the magnet seat 331 is provided with a groove for accommodating the magnet 332. The magnet 332 is fixed in the groove, and the height of the magnet 332 is smaller than the height of the groove, so that when the end face of the magnet seat 331 contacts the pipe, there is a gap between the magnet 332 and the pipe.

[0051] In some embodiments, the magnet seat 331 is made of ceramic, glass or plastic, and the magnet 332 is made of permanent magnets such as neodymium iron boron magnets or cobalt magnets. The gap between the magnet seat 331 and the tube wall is generally reserved at about 0.5 mm, and the height of the gap between the magnet 332 and the tube is set to be in the range of 1 mm-2 mm, so that the magnet 332 will not contact and rub against the tube, avoid scratches on the surface of the tube, and maintain mutual attraction between the magnets 332.

[0052] Furthermore, in order to enable the inner grinding brush 32 to discharge some debris generated during the grinding process in time when grinding the inner wall of the pipe, a chamber 311 is opened inside the disk shell 31, and an exhaust hole 310 connected to the chamber 311 is opened in the middle position of one side of the disk shell 31, and an air pipe 40 is fixedly installed on the disk shell 31, one end of the air pipe 40 is connected to the exhaust hole 310, and the other end is connected to the negative pressure device, and a through hole 320 is provided on the brush holder 321 corresponding to the brush 322, and the through hole 320 is connected to the chamber 311, wherein gaps are reserved between the bristles, so that the debris generated during the grinding process can enter the through hole 320 to the chamber 311 from the gaps between the bristles, and be sucked out by the negative pressure device.

[0053] like Figure 3 As shown, in some embodiments, the outer grinding brush 21, the outer magnetic block 22, the inner grinding brush 32 and the inner magnetic block 33 are all arranged in three groups, the angle between any two adjacent outer grinding brushes 21 is 120°, the angle between the outer magnetic block 22 and the outer grinding brush 21 is 60°, the angle between any two adjacent inner magnetic blocks 33 is 120°, and the angle between the inner magnetic block 33 and the inner grinding brush 32 is 60°. In this way, during the grinding process, the outer wall and the inner wall of the pipe are grinded by three groups of outer grinding brushes 21 and three groups of inner grinding brushes 32, and at the same time, through the magnetic attraction between the three groups of outer magnetic blocks 22 and the inner magnetic blocks 33, the inner grinder 30 can rotate together with the outer grinder 20 to grind the pipe wall.

[0054] Furthermore, the contact surfaces of the outer grinding brush 21 and the inner grinding brush 32 with the pipe are respectively the first grinding surface and the second grinding surface, and the distance between the first grinding surface and the second grinding surface is set to the thickness of the pipe, so that when the outer grinder 20 and the inner grinder 30 are grinding the pipe, the outer grinding brush 21 and the inner grinding brush 32 can just contact the surface wall of the pipe for grinding. At the same time, the distance between the end face of the outer magnetic block 22 and the end face of the inner magnetic block 33 is greater than the thickness of the pipe, so that a certain gap (about 0.5mm) is left between the outer magnetic block 22, the inner magnetic block 33 and the surface wall of the pipe to reduce friction.

[0055] like Figure 3 As shown, an air guide ring 101 is fixedly provided on the vertical plate 10 corresponding to the external grinder 20, an annular air cavity 100 is provided around the outer side of the air guide ring 101, a plurality of evenly distributed air guide holes 102 are provided on the surface of the air guide ring 101, the air guide holes 102 are connected with the annular air cavity 100, a pipe joint 12 connected with the annular air cavity 100 is fixedly provided on the vertical plate 10, and the pipe joint 12 is connected with the external negative pressure device.

[0056] In this way, the debris generated during the grinding process of the outer wall of the pipe by the external grinder 20 will fall around the air guide ring 101, and will be attracted by the negative pressure airflow at the air guide hole 102 and enter the annular air cavity 100, and finally be sucked out by the negative pressure device to reduce dust particles in the working environment.

[0057] like Figure 4 As shown, in order to adaptably adjust the size of the external grinder 20 according to the outer diameter of the pipe, the driving wheel 50 includes a wheel shell 51 and a driving gear wheel 52 rotatably mounted inside the wheel shell 51 .

[0058] In some embodiments, the wheel shell 51 can be made of a hollow disk shell made of stainless steel or aluminum alloy, and the transmission gear plate 52 is connected to the inner side of the wheel shell 51 through a bearing, wherein the first surface of the transmission gear plate 52 is provided with a first clamping plate 53 and a second clamping plate 54 that can move in the radial direction, and the surface of the transmission gear plate 52 is provided with a spiral tooth 521 that meshes with the first clamping plate 53 and the second clamping plate 54 for transmission, and the second surface edge of the transmission gear plate 52 is distributed with conical teeth (not shown in the figure), and the gear wrench that meshes with the teeth can be used to turn the transmission gear plate 52 to adjust the radial movement position of the first clamping plate 53 and the second clamping plate 54. The driving principle is consistent with the driving principle of the three-jaw chuck. When the transmission gear plate 52 rotates, the first clamping plate 53 and the second clamping plate 54 are driven to move synchronously in the radial direction for adjustment.

[0059] Furthermore, in order to facilitate the replacement and maintenance of the external grinding brush 21 and the external magnetic block 22, the number of the first clamping plates 53 corresponds to the number of the external magnetic blocks 22, and the external magnetic blocks 22 are clamped at the ends of the first clamping plates 53. The number of the second clamping plates 54 corresponds to the number of the external grinding brushes 21, and the second clamping plates 54 are clamped at the ends of the external grinding brushes 21. The clamping method can be fixed by snaps or screws.

[0060] An embodiment of the present invention provides a method for grinding a marine ladder pipe, using the above-mentioned marine ladder pipe grinding device, comprising the following steps:

[0061] Selection: According to the diameter and thickness of the pipe, select the outer grinder 20 and the inner grinder 30 that match it, so that the outer grinding brush 21 and the inner grinding brush 32 can fit the outer wall and the inner wall of the pipe at the same time.

[0062] Among them, the selection of the external grinder 20 is to adjust the radial positions of the external grinder brush 21 and the external magnetic block 22 through the transmission wheel 50. During the adjustment process, the external grinder brush 21 is adjusted to fit the outer wall of the pipe. The internal grinder 30 selects a model that matches the inner diameter of the pipe so that the internal grinder brush 32 fits the inner wall of the pipe.

[0063] Installation: Install the inner grinder 30 on the inner side of the end of the pipe, and make the inner grinding brush 32 fit against the inner wall of the pipe. Hold the pipe and place the end with the inner grinder 30 on the inner side of the outer grinder 20, so that the outer grinding brush 21 can fit against the outer wall of the pipe, and align the outer magnetic block 22 and the inner magnetic block 33 in the radial direction.

[0064] Grinding: Turn on the switch of the motor 61 so that the transmission wheel 50 is driven to rotate by the driving wheel 60, and push the pipe by hand to make the pipe slowly pass through the outer grinder 20 and the inner grinder 30 until the surface of the pipe is polished. During the grinding step, auxiliary supporting plates can be set on the front and rear sides of the vertical plate 10 so that the pipe can be polished on the upper surface of the supporting plate, thereby reducing the weight of the pipe when held by hand, and only the pipe needs to be pushed forward.

[0065] Dust removal: When the grinding step is started, the negative pressure device is started. The debris generated during the grinding of the outer wall of the pipe by the external grinder 20 will fall around the air guide ring 101, and will be attracted by the negative pressure airflow at the air guide hole 102 and enter the annular air cavity 100, and will finally be sucked out by the negative pressure device to reduce the dust particles in the working environment. Since there are gaps between the bristles of the internal grinding brush 32, the debris generated by the grinding of the internal grinder 30 can enter the through hole 320 to the chamber 311 through the gaps between the bristles, and will be sucked out by the negative pressure device, reducing the residue of debris inside the pipe and reducing the secondary wear of the pipe wall by the debris.

[0066] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0067] Although embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations may be made to the embodiments without departing from the principles and spirit thereof, and the scope of the embodiments is defined by the appended claims and their equivalents.

[0068] The above description of the implementation mode is not restrictive, and the drawings show only one of the implementation modes, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the scope of protection.

Claims

1. A grinding device for marine ladder pipes, characterized in that: include: A vertical plate (10), wherein a transmission wheel (50) is rotatably mounted on the vertical plate (10); A driving wheel (60) is rotatably mounted on the vertical plate (10) and is capable of driving the transmission wheel disc (50) to rotate; An outer grinder (20) and an inner grinder (30) are provided on the inner side of the transmission wheel (50); the outer grinder (20) is fixed to the inner wall of the transmission wheel (50); the outer grinder (20) comprises a plurality of groups of outer grinding brushes (21) and a plurality of groups of outer magnetic blocks (22); the outer grinding brushes (21) and the outer magnetic blocks (22) are both distributed on the outer side of the pipe; the inner grinder (30) comprises a disc shell (31), a plurality of groups of An inner grinding brush (32) and a plurality of groups of inner magnetic blocks (33), wherein the inner grinding brush (32) and the inner magnetic blocks (33) are distributed on the inner side of the tube, the angles between any two adjacent groups of the outer magnetic blocks (22) and any two adjacent groups of the inner magnetic blocks (33) are the same, and the outer magnetic blocks (22) and the inner magnetic blocks (33) attract each other, so that the inner grinder (30) on the inner side of the tube can rotate along with the outer grinder (20); The inner magnetic block (33) comprises a magnetic seat (331) fixed on the outer wall of the disk shell (31) and a magnet (332) mounted on the magnetic seat (331); a groove for accommodating the magnet (332) is provided at the end of the magnetic seat (331); the magnet (332) is fixed in the groove; and the height of the magnet (332) is less than the height of the groove, so that when the end face of the magnetic seat (331) contacts the pipe, there is a gap between the magnet (332) and the pipe, and the height of the gap is set to 1 mm-2 mm.

2. The grinding device for marine ladder pipes according to claim 1, characterized in that: The inner grinding brush (32) and the inner magnetic block (33) are centrally symmetrically distributed on the peripheral outer wall of the disk shell (31), and along the circumferential direction, the inner grinding brush (32) and the inner magnetic block (33) are alternately distributed; A chamber (311) is provided inside the disk shell (31), an exhaust hole (310) communicating with the chamber (311) is provided at a middle position on one side of the disk shell (31), an air pipe (40) is fixedly mounted on the disk shell (31), one end of the air pipe (40) is communicated with the exhaust hole (310), and the other end is connected to a negative pressure device.

3. The grinding device for marine ladder pipes according to claim 2, characterized in that: The inner grinding brush (32) comprises: A brush seat (321) is slidably mounted in the disk housing (31) along a radial direction; A brush (322) fixedly mounted on the brush holder (321); A spring (323) is fixedly mounted between the brush seat (321) and the disk housing (31), so that the brush seat (321) has elastic potential energy radially outward; Wherein, a through hole (320) is provided on the brush seat (321) at a position corresponding to the brush (322), and the through hole (320) is in communication with the chamber (311).

4. The grinding device for marine ladder pipes according to claim 1, characterized in that: The outer grinding brush (21), the outer magnetic block (22), the inner grinding brush (32) and the inner magnetic block (33) are all arranged in three groups, the angle between any two adjacent outer grinding brushes (21) is 120°, the angle between the outer magnetic block (22) and the outer grinding brush (21) is 60°, the angle between any two adjacent inner magnetic blocks (33) is 120°, and the angle between the inner magnetic block (33) and the inner grinding brush (32) is 60°; The contact surfaces of the outer grinding brush (21) and the inner grinding brush (32) with the tube are respectively a first grinding surface and a second grinding surface, the distance between the first grinding surface and the second grinding surface is set to be the thickness of the tube, and the distance between the end surface of the outer magnetic block (22) and the end surface of the inner magnetic block (33) is greater than the thickness of the tube.

5. The grinding device for marine ladder pipes according to claim 3, characterized in that: An air guide ring (101) is fixedly provided on the vertical plate (10) at a position corresponding to the external grinder (20); an annular air cavity (100) is provided around the outer side of the air guide ring (101); a plurality of evenly distributed air guide holes (102) are provided on the surface of the air guide ring (101); the air guide holes (102) are connected to the annular air cavity (100); a pipe joint (12) connected to the annular air cavity (100) is fixedly provided on the vertical plate (10); the pipe joint (12) is connected to an external negative pressure device.

6. The grinding device for marine ladder pipes according to claim 1, characterized in that: The transmission wheel (50) comprises a wheel shell (51) and a transmission toothed plate (52) rotatably mounted inside the wheel shell (51); a first clamping plate (53) and a second clamping plate (54) capable of moving in a radial direction are provided on a single side surface of the transmission toothed plate (52); and a surface of the transmission toothed plate (52) is provided with helical teeth (521) meshing with the first clamping plate (53) and the second clamping plate (54) for transmission; and when the transmission toothed plate (52) rotates, the first clamping plate (53) and the second clamping plate (54) are driven to move synchronously in a radial direction.

7. The grinding device for marine ladder pipes according to claim 6, characterized in that: The number of the first clamping plates (53) corresponds to the number of the external magnetic blocks (22), and the external magnetic blocks (22) are clamped on the ends of the first clamping plates (53). The number of the second clamping plates (54) corresponds to the number of the external grinding brushes (21), and the second clamping plates (54) are clamped on the ends of the external grinding brushes (21).

8. A method for grinding marine ladder pipes, characterized in that: The grinding device for marine ladder pipes according to claim 5 comprises the following steps: Selection: According to the diameter and thickness of the pipe, the outer grinder (20) and the inner grinder (30) that match the pipe are selected so that the outer grinding brush (21) and the inner grinding brush (32) can fit the outer wall and the inner wall of the pipe at the same time; Installation: installing the inner grinder (30) on the inner side of the end of the pipe so that the inner grinding brush (32) can fit against the inner wall of the pipe, holding the pipe, placing the end with the inner grinder (30) on the inner side of the outer grinder (20) so that the outer grinding brush (21) can fit against the outer wall of the pipe, and aligning the outer magnetic block (22) and the inner magnetic block (33) in the radial direction; Grinding: turning on a switch so that the transmission wheel disc (50) is driven to rotate by the driving wheel (60), and the pipe is pushed by hand, so that the pipe slowly passes through the outer grinder (20) and the inner grinder (30) until the surface of the pipe is completely ground; Dust removal: When the grinding step is started, the negative pressure device is started, and the debris generated by the grinding of the outer grinder (20) can enter the annular air cavity (100) through the air guide holes (102) on the surface of the air guide ring (101) and be sucked out by the negative pressure device. The debris generated by the grinding of the inner grinder (30) can enter the chamber (311) through the through hole (320) and be sucked out by the negative pressure device.

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