Device for internal cutting of steel pipe

Abstract

The invention relates to a device for cutting the interior of a steel pipe. The device comprises a pipe cutting assembly, and the pipe cutting assembly comprises a driving rod, a driven rod, a positioning pin, a cutter and a supporting rod; the supporting rod is provided with a cavity in the axial direction, and the whole driven rod is located in the cavity. The supporting rod and the driven rod are connected through the positioning pin, and the driven rod can rotate around the positioning pin. The cutter is arranged on the front portion of the driven rod and exposed out of the side wall of the supporting rod. The driving rod slidably penetrates through the rear end of the supporting rod, so that the front end of the driving rod is located in the cavity and makes contact with the rear end of the driven rod. The contact surface between the driving rod and the driven rod is an inclined surface, so that the driven rod swings around the positioning pin when being pushed by the driving rod so as to enable the cutter to be located at the cutting position where the cutter cuts the inner wall of the steel pipe, and the driven rod swings back around the positioning pin when the driving rod retreats so as to enable the cutter to retreat to the initial position of the cutter. The device is convenient to retract after the cutter finishes cutting, and the construction efficiency is improved.

Description

Technical Field

[0001] The present disclosure generally relates to the field of chemical equipment cutting, and more specifically, to a device for cutting inside a steel pipe. Background Art

[0002] With the reform and development of coal energy, the modern coal chemical industry, which mainly produces alternative petrochemical raw materials and clean energy, has developed rapidly. It has successively overcome a series of technical difficulties such as coal-to-oil, coal-to-olefins, and coal-to-ethylene glycol, and mastered a large number of independent intellectual property rights for coal gasification and liquefaction. The overall deep processing and transformation of coal has reached the international leading level. In pressure vessels such as petroleum and fertilizer, heat exchanger equipment is very large. For shell and tube heat exchangers such as fixed tube plate heat exchangers and U-tube heat exchangers, usually both ends of all heat exchange tubes (usually steel pipes) are fixed on the tube plate of the heat exchanger and protrude a certain length from the plate surface of the tube plate. In the manufacturing process of this heat exchanger, after the tube insertion (i.e., inserting the heat exchange tubes one by one into the reserved holes on the tube sheet and fixing them by expansion, welding or a combination of both to ensure that the heat exchange tubes and the tube sheet are sealed and firmly connected) is completed, some heat exchange tubes extend longer than the tube sheet surface. At this time, it is necessary to remove the longer portion of the heat exchange tube extending from the tube sheet surface (generally referred to as "surplus"), and this removal process is generally referred to as "flat head" in the art.

[0003] The existing flattening machines for flattening mostly require manual withdrawal of the cutter after the cutter has finished cutting the excess. This results in low efficiency when the number of heat exchange tubes that need flattening is large. Moreover, the cutter is easily in direct contact with the cutter during manual withdrawal, which also poses a safety hazard. When a handheld cutter is used to remove the excess from the outside of the steel pipe, the high-speed rotating cutting blade is prone to breakage during the cutting process, so the operation is more dangerous and can easily cause harm to people around.

[0004] Therefore, how to provide a device for cutting steel pipes with low danger and high construction efficiency is a problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] In view of this, the present disclosure provides a device for cutting inside a steel pipe, which cuts the steel pipe from the inside of the steel pipe, reduces the danger, and facilitates the retraction of the cutter after the cutting is completed, thereby improving the construction efficiency.

[0006] To achieve the above-mentioned purpose, the present disclosure provides a device for cutting inside a steel pipe, which includes a pipe cutting assembly, wherein the pipe cutting assembly includes an active rod, a driven rod, a positioning pin, a cutter and a support rod; the support rod has a cavity in its axial direction, and the driven rod is entirely located in the cavity; the positioning pin connects the support rod and the driven rod in a direction perpendicular to the axial direction of the support rod, and the driven rod is rotatable around the positioning pin; the cutter is arranged at the front part of the driven rod, and cuts the pipe from the driven rod through a cutter hole provided on the side wall of the support rod. The side wall of the support rod is exposed; the active rod can slidably pass through the rear end of the support rod, so that the front end of the active rod is located in the cavity and contacts with the rear end of the driven rod; and the contact surface between the active rod and the driven rod is an inclined surface, so that the driven rod swings around the positioning pin when pushed by the active rod so that the cutter is in the cutting position where the cutter cuts the inner wall of the steel pipe, and the driven rod swings back around the positioning pin when the active rod retreats so that the cutter retreats to the initial position of the cutter.

[0007] Optionally, the device for cutting inside steel pipes also includes a bidirectional thrust ball bearing, a compression spring, a clamping block, an electric push rod and an electric push rod controller; the active rod passes through the shaft ring of the bidirectional thrust ball bearing and is fixedly connected to the shaft ring; the compression spring is sleeved on the active rod, the front end of the compression spring abuts against the end face of the rear end of the support rod, the rear end of the compression spring abuts against and is connected to one seat ring of the bidirectional thrust ball bearing, and the other seat ring of the bidirectional thrust ball bearing is connected to the upper part of the clamping block; the push rod body of the electric push rod is connected to the lower part of the clamping block; and the electric push rod controller is connected to the electric push rod to control the extension and retraction speed of the push rod body in a direction parallel to the axial direction of the active rod.

[0008] Optionally, the active rod is interference fit with the shaft ring of the bidirectional thrust ball bearing.

[0009] Optionally, the pipe cutting assembly also includes a positioning sleeve and an outer shell, which are sequentially sleeved on the periphery of the support rod and spaced apart from the periphery of the support rod; the outer portion of the outer shell is connected to the electric push rod, and the inner portion of the outer shell is provided with an internal thread; the positioning sleeve includes a cylindrical body and two side plates symmetrical to the support rod extending from the front end of the cylindrical body in a direction parallel to the axial direction of the support rod, and there is a gap between the two side plates and the support rod; and the outer wall of the cylindrical body is provided with an external thread threadedly matched with the internal thread, so that the cylindrical body of the positioning sleeve is threadedly connected to the outer shell.

[0010] Optionally, the device for cutting inside a steel pipe also includes a servo motor and an electronic speed regulator, wherein the electronic speed regulator is connected to the servo motor to adjust the rotational speed of the servo motor; the rear portion of the active rod is axially slidably inserted into the output shaft of the servo motor, so that the active rod rotates with the output shaft; and the axial outer wall of the portion of the active rod located in the support rod is axially slidably engaged with the axial inner wall of the support rod.

[0011] Optionally, a groove is axially provided on the outer wall of the rear portion of the active rod, the output shaft of the servo motor is hollow, and a protrusion is axially provided on the inner wall of the output shaft and axially slides with the groove; and the axial outer wall of the portion of the active rod located in the support rod is provided with an axial protrusion of the active rod, and the axial inner wall of the support rod is provided with an axial groove that axially slides with the axial protrusion of the active rod.

[0012] Optionally, the device for cutting inside a steel pipe further comprises a box, and the servo motor is fixedly connected to the inside of the box.

[0013] Optionally, the pipe cutting assembly further comprises a copper sleeve, which is detachably sleeved on the front portion of the support rod and is closer to the front end of the support rod than the cutter hole.

[0014] Optionally, the cutter is detachably arranged on the front portion of the driven rod via a cutter pressing bolt.

[0015] Optionally, the locating pin passes through the side wall of the support rod and the driven rod in sequence from the outside of the support rod in the direction perpendicular to the axial direction of the support rod to connect the support rod with the driven rod; and the inclined surface is inclined toward the cutter hole and is adjacent to the locating pin, so that the driven rod swings around the locating pin when the active rod retreats to make the cutter retreat to the initial position of the cutter.

[0016] Compared with the prior art, the device for cutting inside a steel pipe provided by the present disclosure has at least the following beneficial effects:

[0017] (1) When cutting a steel pipe, the device for cutting inside a steel pipe disclosed in the present invention can extend the support rod and the cutter into the interior of the steel pipe, and use the inclined surface between the active rod and the driven rod to make the active rod push the driven rod, thereby driving the driven rod to swing around the positioning pin, so that the cutter can move toward the inner wall of the steel pipe and reach the cutting position where the inner wall of the steel pipe can be cut. Therefore, the device for cutting inside a steel pipe disclosed in the present invention can cut the steel pipe from the inside of the steel pipe, thereby reducing the danger and improving the safety.

[0018] (2) The device for cutting inside a steel pipe disclosed in the present invention sets the contact surface between the active rod and the driven rod as an inclined surface, so that when the cutter completes cutting, it is only necessary to move the active rod backward so that the pushing force on the driven rod disappears, and the driven rod can automatically swing back around the positioning pin under the action of its own gravity to drive the cutter back to the initial position of the cutter, thereby realizing the cutter withdrawal. This cutter withdrawal method is simple and convenient, improves construction efficiency, avoids direct contact with the cutter, and further improves safety.

[0019] (3) The device for cutting inside a steel pipe disclosed in the present invention is also provided with a bidirectional thrust ball bearing, a compression spring, a clamping block, an electric push rod and an electric push rod controller. When cutting, the clamping block, the bidirectional thrust ball bearing and the active rod can be driven to move axially forward together by operating the electric push rod to apply thrust to the driven rod, which makes the cutting of the steel pipe more convenient. In addition, the compression spring will shrink during the advancement of the clamping block, the bidirectional thrust ball bearing and the active rod. After the cutting is completed, the elastic force of the compression spring can be used to realize the automatic retreat of the active rod, thereby realizing automatic retraction of the knife, which further improves the convenience of retraction. The electric push rod controller can control the extension and retraction speed of the push rod body of the electric push rod, so that the active rod can move forward at a uniform speed, thereby realizing uniform feed, and avoiding the adverse effects of excessive or inconsistent feed speed on the cutting quality.

[0020] (4) The device for cutting inside a steel pipe disclosed in the present invention is also provided with an electronic speed regulator, which can adjust and control the rotation speed of the servo motor, thereby achieving the appropriate rotation speed required for rotary cutting of steel pipes of various diameters and materials, achieving better pipe cutting effect and higher efficiency, and expanding the application scope of the device.

[0021] (5) The device for cutting inside a steel pipe disclosed in the present invention is also provided with a positioning sleeve, which is threadedly connected in the outer shell so that the length of the positioning sleeve extending out of the outer shell can be adjusted. In this way, when cutting the heat exchange tubes of a fixed tube sheet heat exchanger, a U-tube heat exchanger, or other shell and tube heat exchangers, the cylindrical body of the positioning sleeve is first rotated forward so that the front ends of the two side plates located on the periphery of the heat exchange tube exceed the predetermined distance of the cutter and abut against the plate surface of the tube sheet of the heat exchanger. This can realize the positioning of different cutting positions of each heat exchange tube, ensure the accuracy of the cutting position, and make the length of each heat exchange tube exposed from the tube sheet plate surface remain consistent after cutting, thereby meeting the processing requirements of the heat exchanger. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present disclosure, the embodiments of the present disclosure will be further illustrated and described according to the following drawings, which are only used to more conveniently and specifically describe the embodiments of the present disclosure rather than to limit the present disclosure. In the drawings:

[0023] Figure 1It is a structural schematic diagram of a pipe cutting assembly of a device for cutting inside a steel pipe according to an embodiment of the present disclosure;

[0024] Figure 2 is a schematic structural diagram of a device for cutting inside a steel pipe according to an embodiment of the present disclosure; and

[0025] Figure 3 It is a schematic structural diagram of a knife pressing tool and a knife pressing tool bolt of a device for cutting inside a steel pipe according to an embodiment of the present disclosure.

[0026] In the figure: 1. servo motor; 2. electronic speed regulator; 3. active rod; 4. driven rod; 5. positioning pin; 6. cutter; 7. knife pressure bolt; 8. copper sleeve; 9. bidirectional thrust ball bearing; 10. compression spring; 11. clamping block; 12. electric push rod; 13. electric push rod controller; 14. housing; 15. positioning sleeve; 16. support rod. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present disclosure clearer, the specific embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. These embodiments are provided by way of example only. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative work are also within the scope of protection claimed by the present disclosure.

[0028] In the description of the present disclosure, it should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present disclosure.

[0029] In the description of the present disclosure, unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a mechanical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0030] One embodiment of the present disclosure provides a device for cutting inside a steel pipe, which includes a pipe cutting assembly. Figure 1 The pipe cutting assembly includes an active rod 3, a driven rod 4, a positioning pin 5, a cutter 6 and a support rod 16. The support rod 16 has a cavity in its axial direction, and the driven rod 4 is entirely located in the cavity. The positioning pin 5 connects the support rod 16 with the driven rod 4 in a direction perpendicular to the axial direction of the support rod 16, and the driven rod 4 is rotatable around the positioning pin 5. The cutter 6 is arranged at the front of the driven rod 4, and is exposed from the side wall of the support rod 16 through a cutter hole provided on the side wall of the support rod 16. The active rod 3 can slide through the rear end of the support rod 16, so that the front end of the active rod 3 is located in the cavity and contacts with the rear end of the driven rod 4; the contact surface between the active rod 3 and the driven rod 4 is an inclined surface, so that when the driven rod 4 is pushed by the active rod 3, it swings around the positioning pin 5 so that the cutter 6 is in the cutting position where the cutter 6 cuts the inner wall of the steel pipe, and when the active rod 3 retreats, the driven rod 4 swings back around the positioning pin 5 so that the cutter 6 retreats to the initial position of the cutter 6; in this way, when cutting, the active rod 3 is pushed forward first , the active rod 3 pushes the driven rod 4 at the inclined surface, so that the driven rod 4 swings around the positioning pin 5, thereby moving the cutter 6 toward the inner wall of the steel pipe and reaching the cutting position where the inner wall of the steel pipe can be cut; and when the cutting is completed, the active rod 3 retreats, so that the pushing force on the driven rod 4 disappears, so that the driven rod 4 can automatically swing around the positioning pin 5 under the action of its own gravity to drive the cutter 6 to retreat to the initial position of the cutter 6 (that is, the initial position before the cutter 6 moves), thereby realizing the withdrawal of the cutter 6.

[0031] Reference Figure 2In a preferred embodiment of the present disclosure, the device for cutting inside a steel pipe also includes a bidirectional thrust ball bearing 9, a compression spring 10, a clamping block 11, an electric push rod 12 and an electric push rod controller 13. The active rod 3 passes through the shaft ring of the bidirectional thrust ball bearing 9 and is fixedly connected to the shaft ring, so that the active rod 3 and the bidirectional thrust ball bearing 9 can move axially together. The compression spring (for example, a high-strength and strong compression spring can be selected) 10 is sleeved on the active rod 3, the front end of the compression spring 10 abuts against the end face of the rear end of the support rod 16, the rear end of the compression spring 10 abuts against and is connected to one seat ring of the bidirectional thrust ball bearing 9, the other seat ring of the bidirectional thrust ball bearing 9 is connected to the upper part of the clamping block 11, and the push rod body of the electric push rod 12 is connected (for example, a detachable connection made by fasteners such as bolts and nuts) to the lower part of the clamping block 11, so that the electric push rod 12 drives the active rod 3 to move axially with the support rod 16. The dynamic clamping block 11 can drive the bidirectional thrust ball bearing 9 and the active rod 3 to move along the axial direction of the active rod 3, and then drive the driven rod 4 to realize the automatic feeding of the cutter 6 (i.e., movement toward the inner wall of the steel pipe), and after the cutting is completed, the elastic force of the compression spring 10 can be used to realize the automatic retreat of the active rod 3, so as to realize the automatic retreat of the cutter after the cutting is completed, which further improves the convenience of retreat, reduces the time required for manual retreat, and avoids the loss of the cutter blade caused by moving the machine before retreating. The electric push rod controller 13 is connected to the electric push rod 12 to control the telescopic speed of the push rod body in the direction parallel to the axial direction of the active rod 3. Because the feed amount of the cutter 6 is very small during cutting, the traditional electric push rod moves quickly and it is difficult to meet the requirements for cutting quality. The electric push rod controller 13 disclosed in the present invention can control the extension and retraction speed of the push rod body of the electric push rod 12 to 1mm / min, thereby realizing automatic feeding of the cutter 6 according to the cutting speed requirements, and realizing uniform feed (that is, the blade of the cutter 6 moves toward the inner wall of the steel pipe at a uniform speed) and uniform small feed (that is, the blade of the cutter 6 moves toward the inner wall of the steel pipe at a small uniform speed) during the cutting process, which meets the processing quality requirements.

[0032] In a preferred embodiment of the present disclosure, the active rod 3 and the shaft ring of the bidirectional thrust ball bearing 9 are interference fit, that is, the fixed connection between the active rod 3 and the shaft ring of the bidirectional thrust ball bearing 9 is achieved by interference fit. In addition, in order to make the rotation of the active rod 3 more stable, an additional bidirectional thrust ball bearing (not shown in the figure) can be symmetrically arranged on the other side of the clamping block 11 relative to the bidirectional thrust ball bearing 9, and the active rod 3 and the additional bidirectional thrust ball bearing are also interference fit.

[0033] In a preferred embodiment of the present disclosure, the pipe cutting assembly further includes a positioning sleeve 15 and a housing 14, which are sequentially sleeved on the periphery of the support rod 16 and spaced from the periphery of the support rod 16. The exterior of the housing 14 is connected to the electric push rod 12, and the interior of the housing 14 is provided with an internal thread; the positioning sleeve 15 includes a cylindrical body and two side plates extending from the front end of the cylindrical body in a direction parallel to the axial direction of the support rod 16 and symmetrical to the support rod 16, and there are intervals between the two side plates and the support rod 16, and the intervals are preferably equal. The outer wall of the cylindrical body is provided with an external thread that is threadedly matched with the internal thread, so that the cylindrical body of the positioning sleeve 15 is threadedly connected to the housing 14. In a preferred embodiment of the present disclosure, the positioning sleeve 15 is mainly used when cutting the heat exchange tubes of fixed tube plate heat exchangers, U-tube heat exchangers and other shell and tube heat exchangers. Because the positioning sleeve 15 is threadedly connected in the shell 14, the length of the positioning sleeve 15 extending out of the shell 14 can be adjusted. In this way, when cutting the heat exchange tubes of fixed tube plate heat exchangers, U-tube heat exchangers and other shell and tube heat exchangers, the cylindrical body of the positioning sleeve 15 is first rotated forward so that the front ends of the two side plates of the positioning sleeve 15 located on the periphery of the heat exchange tube exceed the predetermined distance of the cutter 6 and abut against the plate surface of the tube plate of the heat exchanger, that is, the positioning of different cutting positions of each heat exchange tube can be achieved, ensuring the accuracy of the cutting position, so that the length of each heat exchange tube exposed to the tube plate surface after cutting remains consistent, thereby meeting the processing requirements of the heat exchanger. Moreover, the threaded connection mode of the positioning sleeve 15 makes it easy to select suitable positioning sleeves 15 of different specifications (mainly referring to the interval between the two side plates and the length of the two side plates) according to the outer diameter of the steel pipe and the required length of each heat exchange tube exposed from the tube sheet surface, thereby realizing the cutting of steel pipes of different models, expanding the scope of use of the device.

[0034] In a preferred embodiment of the present disclosure, the device for cutting inside a steel pipe also includes a servo motor 1 and an electronic speed regulator 2. The electronic speed regulator 2 is connected to the servo motor 1 to adjust the rotation speed of the servo motor 1, so that it can be adjusted to different rotation speeds according to the diameter and material of the steel pipe, thereby achieving the appropriate rotation speed required for rotary cutting of steel pipes of various diameters and materials, with better pipe cutting effect and higher efficiency. The rear portion of the active rod 3 is axially slidably inserted into the output shaft of the servo motor 1, so that the active rod 3 rotates with the output shaft; the axial outer wall of the portion of the active rod 3 located in the support rod 16 is axially slidably engaged with the axial inner wall of the support rod 16.

[0035] Specifically, the connection and cooperation between the active rod 3 and the output shaft of the servo motor 1 can be achieved in the following manner: a groove is axially provided on the outer wall of the rear part of the active rod 3, the output shaft of the servo motor 1 is hollow, and a protrusion is axially provided on the inner wall of the output shaft and axially slides with the groove. In this way, not only can the active rod 3 move axially relative to the output shaft of the servo motor 1, but also the rotation of the output shaft of the servo motor 1 can drive the active rod 3 to rotate circumferentially together.

[0036] Specifically, the connection and cooperation between the active rod 3 and the support rod 16 can be adopted in the following manner: the axial outer wall of the portion of the active rod 3 located in the support rod 16 is provided with an active rod axial protrusion, and the axial inner wall of the support rod 16 is provided with an axial groove that is axially slidably engaged with the active rod axial protrusion, so that not only the active rod 3 can axially slide back and forth in the support rod 16, but also the circumferential rotation of the active rod 3 can drive the support rod 16 to rotate circumferentially together, and further drive the cutter 6 to rotate circumferentially to perform cutting. In addition, the outer wall of the driven rod 4 can also be provided with a driven rod protrusion, and correspondingly, the inner wall of the support rod 16 is provided with a groove that can be engaged with the driven rod protrusion, so that it is more convenient to drive the driven rod 4 and the cutter 6 to rotate circumferentially together through the circumferential rotation of the support rod 16, so that it is more convenient for the cutter 6 to cut more stably.

[0037] In a preferred embodiment of the present disclosure, the device for cutting inside a steel pipe further comprises a box (not shown), and the servo motor 1 is fixedly connected to the inside of the box, so that the servo motor 1 is fixed, thereby increasing the stability of the steel pipe cutting process. The electric push rod 12, the electric push rod controller 13, the servo motor 1 and the electronic speed regulator 2 are all connected to a power supply.

[0038] In a preferred embodiment of the present disclosure, the pipe cutting assembly further includes a copper sleeve 8 for positioning, which is detachably sleeved on the front of the support rod 16 and is closer to the front end of the support rod 16 than the cutter hole. Preferably, the copper sleeve 8 is provided with an internal thread and the front of the support rod 16 is provided with an external thread, so that the copper sleeve 8 is threadedly connected to the front of the support rod 16. This detachable connection mode of the copper sleeve 8 makes it easy to select suitable copper sleeves 8 with different outer diameters according to the inner diameter of the steel pipe, so that different types of steel pipes can be cut, expanding the scope of use of the device. When in use, a copper sleeve 8 with an outer diameter matching the inner diameter of the steel pipe is selected, so that there is a gap of more than ten threads between the copper sleeve 8 and the inner wall of the steel pipe, so that the copper sleeve 8 can play a role in positioning the support rod 16 without affecting the rotation of the copper sleeve 8.

[0039] In a preferred embodiment of the present disclosure, the cutter 6 is a tungsten steel cutter, which has strong rigidity and ensures the cutting of steel pipes of different materials. At the same time, the tungsten steel cutter is wear-resistant and can achieve fast cutting with the use of a high-power servo motor 1, with higher efficiency and better effect. However, the present disclosure is not limited to the selection of the cutter 6. The present disclosure can use any cutter in the art that can cut the inner wall of a steel pipe. The cutter 6 is detachably arranged at the front of the driven rod 4 by a pressure bolt 7; specifically, as Figure 3 As shown, a threaded hole for screwing a knife pressing bolt 7 is provided at the front end of the driven rod 4, and a cutter mounting hole is provided at the portion of the driven rod 4 near its front end. When installing the cutter 6, the cutter 6 is first placed in the cutter mounting hole, and then the knife pressing bolt 7 is screwed into the threaded hole and tightened to press the cutter 6 to complete the installation of the cutter 6; in this way, by loosening the knife pressing bolt 7, the cutters 6 of different lengths can be replaced, thereby realizing the cutting of steel pipes of different types, thereby expanding the scope of use of the device.

[0040] In a preferred embodiment of the present disclosure, the locating pin 5 passes through the side wall of the support rod 16 and the driven rod 4 in sequence from the outside of the support rod 16 in a direction perpendicular to the axial direction of the support rod 16 to connect the support rod 16 with the driven rod 4; the inclined surface is inclined toward the cutter hole and is adjacent to the locating pin 5, so that the driven rod 4 swings around the locating pin 5 when the active rod 3 retreats to make the cutter 6 retreat to the initial position of the cutter 6.

[0041] When a device for cutting inside a steel pipe according to an embodiment of the present disclosure is used to cut a steel pipe, the electric push rod 12 and the electric push rod controller 13 are started, the push rod body of the electric push rod 12 contracts evenly, driving the clamping block 11 to move forward at a uniform speed in a direction parallel to the axial direction of the active rod 3, and then driving the bidirectional thrust ball bearing 9 and the active rod 3 to move forward at a uniform speed in the axial direction of the active rod 3, the active rod 3 pushes the driven rod 4 at the inclined surface, so that the driven rod 4 swings around the positioning pin 5, and then the blade of the cutter 6 moves toward the inner wall of the steel pipe at a uniform speed and reaches the inner wall of the steel pipe; at this time, the servo motor 1 and the electronic speed regulator 2 are started, and the output shaft of the servo motor 1 drives the active rod 3 to rotate circumferentially at a uniform speed, and then drives the support rod 16, the driven rod 4 and the cutter 6 to rotate circumferentially at a uniform speed to cut the inner wall of the steel pipe. As the cutting progresses, the inner wall of the steel pipe at the cutting position gradually becomes thinner. At the same time, the activated electric push rod 12 and the electric push rod controller 13 continuously drive the active rod 3 to move forward at a constant speed, and then drive the blade of the cutter 6 to continuously move toward the inner wall of the outer layer of the steel pipe at a constant speed and reach the inner wall of the outer layer to cut it. The cutter 6 is continuously fed (i.e., moves toward the inner wall of the corresponding layer) and rotated to cut the inner wall of the corresponding layer until the steel pipe at the cutting position is completely removed. Then, the motor servo motor 1 and the electronic speed regulator 2 are turned off, and the electric push rod 12 and the electric push rod controller 13 are turned off (for example, the electric push rod 12 is an electric push rod without a self-locking function, so that the electric push rod 12 will not self-lock after being turned off, so that the push rod body can be automatically pulled out by the elastic force of the compression spring 10), and the elastic force of the compression spring 10 causes the active rod 3 to automatically retreat, and the pushing force of the active rod 3 on the driven rod 4 gradually disappears, and then the driven rod 4 automatically swings around the positioning pin 5 under the action of its own gravity to drive the cutter 6 to retreat to the initial position of the cutter 6, thereby realizing automatic retraction.

[0042] In addition, the device for cutting inside a steel pipe according to an embodiment of the present disclosure can be used not only for cutting ordinary steel pipes, but also for cutting heat exchange tubes of fixed tube-sheet heat exchangers, U-tube heat exchangers, and other shell-and-tube heat exchangers. When the device is used to cut such heat exchange tubes, in addition to using the same method as the steel pipe cutting method described above, the positioning sleeve 15 can be used to position the cutting position before starting the electric push rod 12 and the electric push rod controller 13. Specifically, the cylindrical body of the positioning sleeve 15 is first rotated forward so that the front ends of the two side plates of the positioning sleeve 15 located on the periphery of the heat exchange tube exceed the predetermined distance of the cutter 6 and abut against the plate surface of the tube plate of the heat exchanger. In this way, the positioning of different cutting positions of each heat exchange tube can be achieved, ensuring the accuracy of the cutting position, so that the length of each heat exchange tube exposed from the tube plate surface after cutting remains consistent, thereby meeting the processing requirements of the heat exchanger.

[0043] It should be understood that the drawings in the embodiments of the present disclosure only relate to structures related to the embodiments of the present disclosure, and other structures can refer to the general design. The devices and / or structures in the various embodiments provided in the present disclosure can be combined, modified and / or changed to form new technical solutions. In the absence of creative work, these technical solutions should also be included in the scope of protection claimed in the present disclosure.

[0044] It should be understood that the specific examples provided in the embodiments provided herein are only for the purpose of describing the embodiments of the present disclosure in detail and are not intended to limit the present disclosure. The embodiments of the present disclosure may be practiced without these specific examples. In some embodiments, structures and / or technologies known to those skilled in the art are not shown in detail so as not to obscure the understanding of the present disclosure.

[0045] Although preferred embodiments of the present disclosure have been shown and described herein, it is readily understood by those skilled in the art that these embodiments are provided by way of example only. Those skilled in the art will appreciate a variety of changes, modifications, and substitutions without departing from the present disclosure. It should be understood that the various alternatives to the embodiments of the present disclosure described herein are optionally used to implement the present disclosure. It is intended that the scope of the present disclosure be limited to the appended claims, and that the devices, structures, and equivalents thereof within the scope of these claims are thereby covered.

Claims

1. A device for cutting inside a steel pipe, characterized in that: It comprises a pipe cutting assembly, which comprises an active rod (3), a driven rod (4), a positioning pin (5), a cutting knife (6) and a supporting rod (16); The support rod (16) has a cavity in its axial direction, and the driven rod (4) is entirely located in the cavity; The positioning pin (5) connects the support rod (16) and the driven rod (4) in a direction perpendicular to the axial direction of the support rod (16), and the driven rod (4) is rotatable around the positioning pin (5); The cutter (6) is arranged at the front part of the driven rod (4) and is exposed from the side wall of the support rod (16) through a cutter hole provided on the side wall of the support rod (16); The active rod (3) can slidably pass through the rear end of the support rod (16), so that the front end of the active rod (3) is located in the cavity and contacts the rear end of the driven rod (4); and The contact surface between the active rod (3) and the driven rod (4) is an inclined surface, so that when the driven rod (4) is pushed by the active rod (3), it swings around the positioning pin (5) so that the cutter (6) is in a cutting position where the cutter (6) cuts the inner wall of the steel pipe, and when the active rod (3) retreats, the driven rod (4) swings back around the positioning pin (5) so that the cutter (6) retreats to its initial position.

2. The device for cutting inside a steel pipe according to claim 1, characterized in that: It also includes a bidirectional thrust ball bearing (9), a compression spring (10), a pressing block (11), an electric push rod (12) and an electric push rod controller (13); The active rod (3) passes through the shaft ring of the bidirectional thrust ball bearing (9) and is fixedly connected to the shaft ring; The compression spring (10) is sleeved on the active rod (3), the front end of the compression spring (10) abuts against the end surface of the rear end of the support rod (16), the rear end of the compression spring (10) abuts against and is connected to one race of the bidirectional thrust ball bearing (9), and the other race of the bidirectional thrust ball bearing (9) is connected to the upper part of the clamping block (11); The push rod body of the electric push rod (12) is connected to the lower part of the pressing block (11); and The electric push rod controller (13) is connected to the electric push rod (12) to control the extension and retraction speed of the push rod body in a direction parallel to the axial direction of the active rod (3).

3. The device for cutting inside a steel pipe according to claim 2, characterized in that: The active rod (3) is interference fit with the shaft ring of the bidirectional thrust ball bearing (9).

4. The device for cutting inside a steel pipe according to claim 2, characterized in that: The pipe cutting assembly further comprises a positioning sleeve (15) and a shell (14), wherein the positioning sleeve (15) and the shell (14) are sequentially sleeved on the periphery of the support rod (16) and are spaced apart from the periphery of the support rod (16); The exterior of the housing (14) is connected to the electric push rod (12), and the interior of the housing (14) is provided with an internal thread; The positioning sleeve (15) comprises a cylindrical body and two side plates extending from the front end of the cylindrical body in a direction parallel to the axial direction of the support rod (16) and symmetrical with respect to the support rod (16), and there is a gap between the two side plates and the support rod (16); and The outer wall of the cylindrical body is provided with an external thread that is threadably matched with the internal thread, so that the cylindrical body of the positioning sleeve (15) is threadably connected in the outer shell (14).

5. The device for cutting inside a steel pipe according to claim 1, characterized in that: It also includes a servo motor (1) and an electronic speed regulator (2), wherein the electronic speed regulator (2) is connected to the servo motor (1) to adjust the rotation speed of the servo motor (1); The rear portion of the active rod (3) is axially slidably inserted into the output shaft of the servo motor (1), so that the active rod (3) rotates together with the output shaft; and The axial outer wall of the portion of the active rod (3) located in the support rod (16) is axially slidably engaged with the axial inner wall of the support rod (16).

6. The device for cutting inside a steel pipe according to claim 5, characterized in that: The outer wall of the rear portion of the active rod (3) is axially provided with a groove, the output shaft of the servo motor (1) is hollow, and the inner wall of the output shaft is axially provided with a protrusion that is axially slidably engaged with the groove; and The axial outer wall of the portion of the active rod (3) located in the support rod (16) is provided with an active rod axial protrusion, and the axial inner wall of the support rod (16) is provided with an axial groove axially slidingly engaged with the active rod axial protrusion.

7. The device for cutting inside a steel pipe according to claim 5, characterized in that: It also comprises a box body, and the servo motor (1) is fixedly connected inside the box body.

8. The device for cutting inside a steel pipe according to claim 1, characterized in that: The pipe cutting assembly further comprises a copper sleeve (8), which is detachably sleeved on the front part of the support rod (16) and is closer to the front end of the support rod (16) than the cutter hole.

9. The device for cutting inside a steel pipe according to claim 1, characterized in that: The cutter (6) is detachably arranged on the front part of the driven rod (4) via a cutter pressing bolt (7).

10. The device for cutting inside a steel pipe according to claim 1, characterized in that: The positioning pin (5) passes through the side wall of the support rod (16) and the driven rod (4) in sequence from the outside of the support rod (16) in the direction perpendicular to the axial direction of the support rod (16) to connect the support rod (16) with the driven rod (4); and The inclined surface is inclined toward the cutter hole and is adjacent to the positioning pin (5), so that the driven rod (4) swings back around the positioning pin (5) when the active rod (3) retreats to make the cutter (6) retreat to the initial position of the cutter (6).

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