阅读说明：本技术 一种汽轮机检修用的管道扩张工具及检修方法 (Pipeline expansion tool for steam turbine maintenance and maintenance method ) 是由 吕昌恒 于 2020-10-20 设计创作，主要内容包括：本发明公开了一种汽轮机检修用的管道扩张工具及检修方法,所述扩张工具使用时处于空心管道内,且扩张工具可将空心管道的硬质部分、软质部分扩张；所述扩张工具包括：作为总支撑的圆筒、能够扩张自身径向的扩张件；所述圆筒沿横向长度延伸且其为中空结构,圆筒具有开口相对的第一端部和第二端部,第一端部和第二端部之间直线连通；所述扩张件设置于第一端部外侧；使用扩张工具将空心管道的扩张分步骤进行,减少了瞬间应力,在分步骤的顶抵中实现了顶抵力度和顶抵范围的控制,以使顶抵均匀,不会对空心管道产生损坏且空心管道受到顶抵后的形变小,并实现均匀扩张。(The invention discloses a pipeline expansion tool for turbine maintenance and a maintenance method, wherein the expansion tool is positioned in a hollow pipeline when in use, and the expansion tool can expand a hard part and a soft part of the hollow pipeline; the expanding tool includes: a cylinder as a general support, an expansion member capable of expanding its own radial direction; the cylinder extends along the transverse length and is of a hollow structure, the cylinder is provided with a first end part and a second end part which are opposite in opening, and the first end part and the second end part are communicated in a straight line; the expansion piece is arranged outside the first end part; the expansion of the hollow pipeline is carried out step by using the expansion tool, the instantaneous stress is reduced, the control of the abutting force and the abutting range is realized in the abutting of the step, so that the abutting is uniform, the hollow pipeline cannot be damaged, the deformation of the hollow pipeline after the abutting is small, and the uniform expansion is realized.)

1. A pipeline expansion tool for turbine maintenance is characterized in that the expansion tool is positioned in a hollow pipeline when in use, and the expansion tool can expand a hard part and a soft part of the hollow pipeline;

the expanding tool includes: a cylinder as a general support, an expansion member capable of expanding its own radial direction; the cylinder extends along the transverse length and is of a hollow structure, the cylinder is provided with a first end part and a second end part which are opposite in opening, and the first end part and the second end part are communicated in a straight line;

the expansion part is arranged on the outer side of the first end part and comprises a detachably mounted ring body, two section rings positioned on the radial outer side of the ring body, and a section rod which is arranged between the section rings and the ring body and can move along the radial direction of the ring body, wherein one end of the section rod is fixedly connected with the section rings, the other end of the section rod can be movably inserted into a through hole on the side surface of the ring body and extends to the space on the inner side of the ring body, the section of each section ring is one fourth of the section of a perfect circle, and the section rings are driven to move by the section rod moving along the; the expansion piece also comprises a conversion body, wherein the conversion body is inserted into the space on the inner side of the ring body, and the outer side of the conversion body is kept attached to the other end of the section rod when the conversion body is inserted into the space.

2. The pipe expanding tool for steam turbine overhaul according to claim 1, wherein the ring body is detachably mounted at the first end of the cylinder through screws, the outer diameter and the inner diameter of the ring body are consistent with those of the first end of the cylinder, and a through hole corresponding to the direction of the segment rod is formed in the side surface of the ring body in a penetrating manner.

3. The steam turbine service pipe expanding tool of claim 1, wherein the surface of the segment ring near the ring body is a first ring surface, the surface far away from the ring body is a second ring surface, the first ring surface is fixedly connected with one end of the segment rod, the second ring surface is provided with an inclined surface and a plane, the surface of the second ring surface near the first end is a plane, the surface far away from the first end is an inclined surface, the plane and the inclined surface are in transition through a break angle, and the inclined surface is a surface which is inclined inwards in the radial direction of the segment ring relative to the plane.

4. The pipe expanding tool for steam turbine maintenance according to claim 3, wherein the other end of the segment rod is fixedly connected with a stop block after extending to the space, the cross section of the stop block is polygonal, the diameter of the stop block is larger than that of the through hole, the other end of the stop rod is attached to the outer side of the conversion body through the stop block, and the number of the segment rods fixedly connected with each segment ring is three.

5. The pipe expanding tool for steam turbine maintenance according to claim 1, wherein the transition body has a conical shape, the diameter of the transition body is gradually reduced toward the ring body, the maximum diameter of the transition body is consistent with the inner diameter of the cylinder, and the inner surface of the cylinder is a smooth surface.

6. The pipe expanding tool for steam turbine service of claim 1, further comprising: the force application part of expansion effort is applied to the sub-assembly, and the effort direction of force application part keeps perpendicular with the expansion direction of expansion piece, force application part sets up in the outside of second tip, and force application part is multistage electric putter, electric putter fixed connection is in the second tip outside, and electric putter's telescopic link inserts the drum and extends the first end of drum, and electric putter's telescopic link and conversion body fixed connection.

7. The steam turbine overhauling pipeline expanding tool as recited in claim 1, wherein the first annular surface of the segment ring is provided with a step block, a step area is formed between the surface of the step block and the end surface of the segment ring, an air cushion is arranged in the step area, the air cushion is arc-shaped and is communicated with the front surface of the ring body through a plugging air pipe, and the front surface of the ring body is provided with a sealing structure.

8. A maintenance method is characterized in that: a pipe-expanding tool for steam turbine service comprising any of the steam turbine service methods of claims 1 to 7, said service method comprising the steps of:

s1, pre-expanding the hard part of the hollow pipe: aligning the expansion tool with the hard part, inserting the segment ring into the hard part, moving the segment ring outwards along the radial direction of the segment ring, enabling the inclined plane of the second ring surface to abut against the inner wall of the hard part, and enabling the inner wall of the hard part to form a surface consistent with the inclined plane after abutting is completed;

s2, expanding the hard part of the hollow pipe: moving the segment ring in the step S1 inward along the radial direction thereof, retracting the segment ring, moving the segment ring transversely inward into the hard part again so that the plane of the second ring surface is aligned with the inner wall in the step S1, moving the segment ring outward along the radial direction thereof so that the plane of the second ring surface abuts against the inner wall of the hard part, and flattening the inner wall of the hard part from an inclined state after the abutment is completed;

s3, expanding the full pipe wall of the hard part of the hollow pipe: circumferentially rotating the expansion tool ninety degrees and repeating steps S1 and S2;

s4, expanding the soft part of the hollow pipe: the expansion tool is aligned with the soft segment and the segmented ring is inserted into the soft segment,

connect plug trachea and ring body openly intercommunication, move outward along its radial with the section ring and the air cushion is aerifyd until accomplishing the inflation simultaneously to make the section ring pass through the air cushion top and support soft partial inner wall and expand soft partial inner wall.

S5, expanding the full tube wall of the soft part of the hollow tube: the expansion tool is rotated circumferentially ninety degrees and step S3 is repeated.

9. The service method of claim 8, wherein: in the steps S1 and S2, the specific process of moving the segment ring radially outward is as follows:

s11, starting the electric push rod, enabling the telescopic rod of the electric push rod to extend to push the conversion body, enabling the conversion body to move towards the direction of the ring body and gradually insert into the ring body, and enabling the outer side of the conversion body to abut against the stop block and enable the stop block to radially abut against the outer side of the ring body in the inserting process to achieve outward movement of the section ring;

in step S2, the specific process of moving the segment ring radially inward is as follows:

s21, starting the electric push rod, wherein the telescopic rod of the electric push rod is shortened to pull back the conversion body, the conversion body returns to the cylinder, is separated from the stop block and does not abut against the stop block any more, and loses the inward movement of the support rear ring.

In steps S11 and S21, the air pipe is not communicated with the front surface of the ring body.

10. The service method of claim 8, wherein: in step S4, the specific process of moving the segment ring radially outward while inflating the cushion until the expansion is completed is:

s41, the plug air pipe is communicated with the front side of the ring body, the electric push rod is started, the telescopic rod of the electric push rod extends to push the conversion body, the conversion body moves towards the direction of the ring body and is gradually inserted into the ring body, and when the stop block is pushed against the outer side of the conversion body in the insertion process, the air inside the cylinder and the ring body is extruded to the air cushion through the plug air pipe, so that the air cushion is inflated until the expansion is completed.

Technical Field

The invention relates to the technical field of steam turbines, in particular to a pipeline expanding tool for steam turbine maintenance and a maintenance method.

Background

The steam turbine is also called as a steam turbine engine, and is a rotary steam power device.A high-temperature high-pressure steam passes through a fixed nozzle to become an accelerated airflow and then is sprayed onto blades, so that a rotor provided with blade rows rotates, and simultaneously, the rotor does work outwards. Steam turbines are the main equipment of modern thermal power plants, also used in the metallurgical industry, chemical industry, ship power plants, having a plurality of critical pipes, such as: the main steam pipeline is a high-temperature and high-pressure steam pipeline (hard pipeline) between the superheater outlet header and the high-pressure main valve interface; a main water supply pipeline which is a high-pressure boiler supply water pipeline (soft pipeline) between the outlet of the electric water supply pump and the inlet header interface of the economizer; the soft and hard pipelines need to be periodically overhauled after being used for a long time, but because the diameter of the pipe orifice of the pipeline is fixed, part of tools cannot enter the pipeline due to size limitation, the expansion force is directly applied to the side wall of the pipeline by the existing expansion tool, the damage to the side wall of the pipeline is large, in addition, the acting force causes uneven expansion of the pipeline, the damage is overlarge after the expansion and is difficult to recover, in addition, the expansion mode only can deal with hard pipelines, and the pipeline damage is caused when the expansion mode faces soft pipelines.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a pipeline expansion tool for turbine maintenance and a maintenance method, wherein the expansion of a hollow pipeline is carried out by steps by using the expansion tool, so that the instantaneous stress is reduced, the control of the abutting force and the abutting range is realized in the abutting of the steps, the abutting is uniform, the hollow pipeline cannot be damaged, the deformation of the hollow pipeline after abutting is small, and the uniform expansion is realized.

In order to achieve the purpose, the pipeline expanding tool for the steam turbine maintenance is adopted, when in use, the expanding tool is positioned in a hollow pipeline, and the expanding tool can expand a hard part and a soft part of the hollow pipeline;

the expanding tool includes: a cylinder as a general support, an expansion member capable of expanding its own radial direction; the cylinder extends along the transverse length and is of a hollow structure, the cylinder is provided with a first end part and a second end part which are opposite in opening, and the first end part and the second end part are communicated in a straight line;

the expansion part is arranged on the outer side of the first end part and comprises a detachably mounted ring body, two section rings positioned on the radial outer side of the ring body, and a section rod which is arranged between the section rings and the ring body and can move along the radial direction of the ring body, wherein one end of the section rod is fixedly connected with the section rings, the other end of the section rod can be movably inserted into a through hole on the side surface of the ring body and extends to the space on the inner side of the ring body, the section of each section ring is one fourth of the section of a perfect circle, and the section rings are driven to move by the section rod moving along the; the expansion piece also comprises a conversion body, wherein the conversion body is inserted into the space on the inner side of the ring body, and the outer side of the conversion body is kept attached to the other end of the section rod when the conversion body is inserted into the space.

As the optimization of the scheme, the ring body is detachably arranged at the first end part of the cylinder through the screw, the outer diameter and the inner diameter of the ring body are consistent with the first end part of the cylinder, and the side surface of the ring body is provided with the through hole corresponding to the direction of the section rod in a penetrating mode.

As an optimization of the above scheme, a surface of the segment ring close to the ring body is a first ring surface, a surface far away from the ring body is a second ring surface, the first ring surface is fixedly connected with one end of the segment rod, the second ring surface is provided with an inclined surface and a plane, the surface of the second ring surface close to the first end portion is the plane, the surface far away from the first end portion is the inclined surface, the plane and the inclined surface are in transition through a break angle, and the inclined surface is a surface which is inclined inwards in the radial direction of the segment ring relative to the plane.

As the optimization of above-mentioned scheme, fixedly connected with dog behind the other end of section pole extended the space, and the cross-section of dog is the polygon, and the diameter of dog is greater than the diameter of through-hole, and the other end of shelves pole passes through the outside laminating of dog and conversion body, and every section ring fixed connection's section pole quantity is three.

Preferably, the converter is conical, the diameter of the converter is gradually reduced towards the ring body, the maximum diameter of the converter is consistent with the inner diameter of the cylinder, and the inner surface of the cylinder is a smooth surface.

As an optimization of the above, the expanding tool further comprises: the force application part of expansion effort is applied to the sub-assembly, and the effort direction of force application part keeps perpendicular with the expansion direction of expansion piece, force application part sets up in the outside of second tip, and force application part is multistage electric putter, electric putter fixed connection is in the second tip outside, and electric putter's telescopic link inserts the drum and extends the first end of drum, and electric putter's telescopic link and conversion body fixed connection.

As an optimization of the scheme, the first ring surface of the section ring is provided with a step block, a step area is formed between the surface of the step block and the end surface of the section ring, an air cushion is arranged in the step area, the air cushion is arc-shaped and is communicated with the front surface of the ring body through a plugging air pipe, and the front surface of the ring body is a sealing structure;

the invention also provides a maintenance method, which comprises any pipeline expanding tool for turbine maintenance, and the maintenance method comprises the following steps:

s1, pre-expanding the hard part of the hollow pipe: aligning the expansion tool with the hard part, inserting the segment ring into the hard part, moving the segment ring outwards along the radial direction of the segment ring, enabling the inclined plane of the second ring surface to abut against the inner wall of the hard part, and enabling the inner wall of the hard part to form a surface consistent with the inclined plane after abutting is completed;

s2, expanding the hard part of the hollow pipe: moving the segment ring in the step S1 inward along the radial direction thereof, retracting the segment ring, moving the segment ring transversely inward into the hard part again so that the plane of the second ring surface is aligned with the inner wall in the step S1, moving the segment ring outward along the radial direction thereof so that the plane of the second ring surface abuts against the inner wall of the hard part, and flattening the inner wall of the hard part from an inclined state after the abutment is completed;

s3, expanding the full pipe wall of the hard part of the hollow pipe: circumferentially rotating the expansion tool ninety degrees and repeating steps S1 and S2 to expand the full tube wall of the hard segment;

s4, expanding the soft part of the hollow pipe: the expansion tool is aligned with the soft segment and the segmented ring is inserted into the soft segment,

connect plug trachea and ring body openly intercommunication, move outward along its radial with the section ring and the air cushion is aerifyd until accomplishing the inflation simultaneously to make the section ring pass through the air cushion top and support soft partial inner wall and expand soft partial inner wall.

S5, expanding the full tube wall of the soft part of the hollow tube: the expansion tool is rotated circumferentially ninety degrees and step S3 is repeated to expand the full tube wall of the soft segment.

As a further optimization of the maintenance method, in the steps S1 and S2, the specific process of moving the segment ring radially outward along the segment ring is as follows:

s11, starting the electric push rod, enabling the telescopic rod of the electric push rod to extend to push the conversion body, enabling the conversion body to move towards the direction of the ring body and gradually insert into the ring body, and enabling the outer side of the conversion body to abut against the stop block and enable the stop block to radially abut against the outer side of the ring body in the inserting process to achieve outward movement of the section ring;

in step S2, the specific process of moving the segment ring radially inward is as follows:

s21, starting the electric push rod, wherein the telescopic rod of the electric push rod is shortened to pull back the conversion body, the conversion body returns to the cylinder, is separated from the stop block and does not abut against the stop block any more, and loses the inward movement of the support rear ring.

In steps S11 and S21, the air pipe is not communicated with the front surface of the ring body.

As a further optimization of the maintenance method, in step S4, the specific process of moving the segment ring radially outward along the segment ring while inflating the air cushion until the expansion is completed is as follows:

s41, the plug air pipe is communicated with the front side of the ring body, the electric push rod is started, the telescopic rod of the electric push rod extends to push the conversion body, the conversion body moves towards the direction of the ring body and is gradually inserted into the ring body, and when the stop block is pushed against the outer side of the conversion body in the insertion process, the air inside the cylinder and the ring body is extruded to the air cushion through the plug air pipe, so that the air cushion is inflated until the expansion is completed.

The pipeline expanding tool for turbine maintenance and the maintenance method have the following beneficial effects:

the expansion piece in the expansion tool can expand in the radial direction, the expansion piece can gradually abut against the inner wall of the hollow pipeline by utilizing the expansion in the radial direction under the condition of being attached to the inner wall of the hollow pipeline, so that the inner wall of the hollow pipeline is gradually deformed to realize expansion, and the abutting of the expansion piece forms pre-expansion and re-expansion on the hollow pipeline, so that the expansion of the hollow pipeline is performed in steps, the instant stress is reduced, the abutting strength and the abutting range are controlled in the abutting in the steps, the abutting is uniform, the hollow pipeline cannot be damaged, the deformation of the hollow pipeline after the abutting is small, and the uniform expansion is realized;

outside the hard part expansion of realizing hollow pipeline through propping, can also expand the expansion with the air cushion in its outside together when expansion piece expansion self is radial to utilize soft air cushion top to prop the soft part of hollow pipeline, realize the expansion of soft part, and replace the damage of hard contact to soft part.

Drawings

FIG. 1 is an exploded view of the overall structure of the present invention;

FIG. 2 is a schematic view of the extender of the present invention;

FIG. 3 is a schematic view of the cushion inflation configuration of the stent of the present invention;

FIG. 4 is an enlarged view of the area A in FIG. 3;

FIG. 5 is a side view of the overall structure of the present invention;

FIG. 6 is a schematic side view of the air cushion after inflation in accordance with the overall construction of the present invention;

FIG. 7 is a schematic cross-sectional view of a hollow conduit according to the present invention;

FIG. 8 is a schematic view of a rigid portion of a hollow pipe after pre-expansion in a service method of the present invention;

FIG. 9 is a schematic view of a hard portion of a hollow pipe during re-expansion in a service method of the present invention;

FIG. 10 is a schematic view of the hard portion of the hollow pipe after re-expansion in the service method of the present invention;

FIG. 11 is a schematic view of the soft portion of the hollow conduit after expansion in the service method of the present invention;

in the figure: the device comprises a cylinder 1, a first end part 2, a second end part 3, a ring body 4, a segment ring 5, a segment rod 6, a conversion body 7, an inclined plane 8, a plane 9, a stop block 10, an electric push rod 11, a step block 12, an air cushion 13, a plugging air pipe 14, a hollow pipeline 15, a hard part 16 and a soft part 17.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and examples. It should be understood, however, that the description herein of specific embodiments is only intended to illustrate the invention and not to limit the scope of the invention.

It should be noted that when an element is referred to as being "disposed on," or provided with "another element, it can be directly on the other element or intervening elements may also be present, when an element is referred to as being" connected, "or coupled to another element, it can be directly on the other element or intervening elements may be present, and" fixedly coupled "means that the element is fixedly coupled in many ways, which are not intended to be within the scope of the present disclosure, the terms" vertical, "" horizontal, "" left, "" right, "and the like are used herein for illustrative purposes only and are not intended to be a single embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the terms used herein in the specification are for the purpose of describing particular embodiments only and are not intended to limit the present invention, and the term "and/or" as used herein includes any and all combinations of one or more of the associated listed items;

referring to the accompanying drawings of the specification 1-11, the invention provides a technical scheme that a pipeline expanding tool for steam turbine maintenance is positioned in a hollow pipeline 15 when in use, and the expanding tool can expand a hard part 16 and a soft part 17 of the hollow pipeline 15;

referring specifically to fig. 1-4, the expansion tool comprises: a cylinder 1 as a total support, an expansion member capable of expanding its own radial direction; the cylinder 1 extends along the transverse length and is of a hollow structure, the cylinder 1 is provided with a first end part 2 and a second end part 3 which are opposite in opening, and the first end part 2 and the second end part 3 are communicated in a straight line;

the expansion piece is arranged on the outer side of the first end part 2 and comprises a detachable ring body 4, two section rings 5 positioned on the radial outer side of the ring body 4 and a section rod 6 which is arranged between the section rings 5 and the ring body 4 and can move along the radial direction of the ring body 4, one end of the section rod 6 is fixedly connected with the section rings 5, the other end of the section rod 6 can be movably inserted into a through hole on the side surface of the ring body 4 and extends to the space on the inner side of the ring body 4, the section of each section ring 5 is one fourth of the section of a perfect circle, and the section rings 5 are driven to move by the radial movement of the section rod 6 along; the expansion piece also comprises a conversion body 7, wherein the conversion body 7 is inserted into the space on the inner side of the ring body 4, and the outer side of the conversion body 7 is kept attached to the other end of the section rod 6 when being inserted into the space.

Specifically, the ring body 4 is detachably mounted at the first end 2 of the cylinder 1 through a screw, the outer diameter and the inner diameter of the ring body 4 are consistent with the first end 2 of the cylinder 1, and a through hole corresponding to the direction of the section rod 6 is formed in the side surface of the ring body 4 in a penetrating mode.

Referring to fig. 5-6 specifically, the surface of the segment ring 5 close to the ring body 4 is a first ring surface, the surface far away from the ring body 4 is a second ring surface, the first ring surface is fixedly connected with one end of the segment rod 6, the second ring surface is provided with an inclined surface 8 and a plane 9, the surface of the second ring surface close to the first end 2 is the plane 9, the surface far away from the first end 2 is the inclined surface 8, the plane 9 and the inclined surface 8 are in transition through a break angle, the break angle is greater than 45 degrees, and the inclined surface 8 is a surface which is inclined inward along the radial direction of the segment ring 5 relative to the plane 9.

In fig. 4, the other end of the segment rod 6 is fixedly connected with a stop block 10 after extending to the space, the cross section of the stop block 10 is polygonal, the diameter of the stop block 10 is larger than that of the through hole, the other end of the stop rod is attached to the outer side of the conversion body 7 through the stop block 10, and the number of the segment rods 6 fixedly connected with each segment ring 5 is three.

In the present embodiment, the conversion body 7 has a conical shape, the diameter of the conversion body 7 is gradually reduced toward the ring body 4, the maximum diameter of the conversion body 7 coincides with the inner diameter of the cylinder 1, and the inner surface of the cylinder 1 is a smooth surface.

In this embodiment, the expanding tool further comprises: the force application member applies an expansion force to the assembly member, the direction of the force application member is perpendicular to the expansion direction of the expansion member, the force application member is arranged outside the second end portion 3, the force application member is a multi-stage electric push rod 11, the electric push rod 11 is fixedly connected outside the second end portion 3, a telescopic rod of the electric push rod 11 is inserted into the cylinder 1 and extends to the first end portion 2 of the cylinder 1, and the telescopic rod of the electric push rod 11 is fixedly connected with the conversion body 7.

The first ring surface of the section ring 5 is provided with a step block 12, a step area is formed between the surface of the step block 12 and the end surface of the section ring 5, an air cushion 13 is arranged in the step area, the air cushion 13 is arc-shaped, the air cushion 13 is communicated with the front surface of the ring body 4 through a plugging air pipe 14, the front surface of the ring body 4 is of a sealing structure, namely, after the whole assembly, the cylinder 1 is communicated with the ring body 4, the ring body 4 is communicated with the air cushion 13 only through the air pipe, when the telescopic rod of the electric push rod 11 pushes the conversion body 7 to move towards the direction of the ring body 4, the conversion body 7 synchronously extrudes the gas in the cylinder 1 to move towards the direction of the ring body 4, so that the gas is input into the air cushion 13 through the air pipe; the expansion of the soft part 17 is realized by utilizing the soft air cushion 13 to abut against the soft part 17 of the hollow pipeline 15 and replace the damage of hard contact to the soft part 17 by expanding the air cushion 13 at the outer side together when the expansion piece expands in the radial direction.

The embodiment also provides a maintenance method, which comprises 7 any one of the pipeline expanding tools for turbine maintenance, and the maintenance method comprises the following steps:

referring to fig. 8, S1, hard portion 16 of pre-expanded hollow pipe 15: aligning the expanding tool with the hard part 16 and inserting the segment ring 5 into the hard part 16, moving the segment ring 5 outwards along the radial direction of the segment ring, so that the inclined surface 8 of the second ring surface is pressed against the inner wall of the hard part 16, and forming a surface consistent with the inclined surface 8 on the inner wall of the hard part 16 after the pressing is finished;

referring to fig. 9-10, S2, the hard portion 16 of the re-expanded hollow conduit 15: moving the segment ring 5 in step S1 inward along the radial direction thereof, retracting the segment ring 5, moving the segment ring 5 transversely inward into the hard part 16 to align the plane 9 of the second ring surface with the inner wall in step S1, moving the segment ring 5 outward along the radial direction thereof to press the plane 9 of the second ring surface against the inner wall of the hard part 16, and flattening the inner wall of the hard part 16 by tilting after the pressing is completed;

s3, expanding the full tube wall of the hard part 16 of the hollow tube 15: circumferentially rotating the expansion tool ninety degrees and repeating steps S1 and S2 to expand the full tube wall of the hard segment 16;

see fig. 11, S4, expanding the soft portion 17 of the hollow tube 15: aligning the expanding tool with the soft part 17 and inserting the segment ring 5 into the soft part 17, communicating the plug air tube 14 with the front surface of the ring body 4, moving the segment ring 5 outwards along the radial direction thereof while inflating the air cushion 13 until the expansion is completed, so that the segment ring 5 abuts against the inner wall of the soft part 17 through the air cushion 13 and expands the inner wall of the soft part 17, S5, expanding the whole tube wall of the soft part 17 of the hollow tube 15: the expansion tool is circumferentially rotated ninety degrees and step S3 is repeated to expand the full tube wall of the soft segment 17.

Note that, in steps S1 and S2, the specific process of moving the segment ring 5 radially outward is as follows: s11, starting the electric push rod 11, extending a telescopic rod of the electric push rod 11 to push the conversion body 7, enabling the conversion body 7 to move towards the ring body 4 and to be gradually inserted into the ring body 4, and in the inserting process, pushing the stop block 10 against the outer side of the conversion body 7 and pushing the stop block 10 outwards along the radial direction of the ring body 4 to realize the outward movement of the section ring 5;

s21, starting the electric push rod 11, shortening the telescopic rod of the electric push rod 11 to pull back the conversion body 7, returning the conversion body 7 into the cylinder 1, separating the conversion body 7 from the stop block 10 and not abutting against the stop block, losing the inward movement of the rear section ring 5 after support, and in the steps S11 and S21, not communicating the plugging air pipe 14 with the front side of the ring body 4; in general, the expansion piece can gradually abut against the inner wall of the hollow pipeline 15 by utilizing the radial expansion of the expansion piece under the condition of being attached to the inner wall of the hollow pipeline 15, so that the inner wall of the hollow pipeline 15 is gradually deformed to realize expansion, and the abutting of the expansion piece forms pre-expansion and re-expansion on the hollow pipeline 15, so that the expansion of the hollow pipeline 15 is performed in steps, the instant stress is reduced, the abutting strength and the abutting range are controlled in the step abutting, the abutting is uniform, the hollow pipeline 15 cannot be damaged, the deformation of the hollow pipeline 15 after abutting is small, and the uniform expansion is realized;

in addition, in step S4, the specific process of moving the segment ring 5 radially outward along the segment ring while inflating the cushion 13 until the inflation is completed is: s41, the plug air pipe 14 is communicated with the front side of the ring body 4, the electric push rod 11 is started, the telescopic rod of the electric push rod 11 extends to push the conversion body 7, the conversion body 7 moves towards the ring body 4 and is gradually inserted into the ring body 4, and when the stop block 10 is pushed against the outer side of the conversion body 7 in the insertion process, air in the cylinder 1 and the ring body 4 is extruded to the air cushion 13 through the plug air pipe 14, so that the air cushion 13 is inflated until the expansion is completed.

It should be understood that the present invention is not limited to the particular embodiments described herein, but is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.