CN116492697B - A low-cost built-in reboiler and its manufacturing method - Google Patents

Abstract

The invention discloses a low-cost embedded reboiler and a manufacturing method thereof, belongs to the technical field of separation equipment, and solves the problems of multiple and complex production procedures and high manufacturing cost of the traditional reboiler. The welding device mainly comprises a barrel, an upper tube plate and a lower tube plate which are welded at two ends of the barrel respectively, wherein the upper tube plate is embedded in the barrel and a short joint II, the lower tube plate is embedded in the barrel and the short joint I, and the quick embedding of the tube plates is realized through a supporting claw and a positioning locking plate of a welding assisting mechanism. The structural improvement and the manufacturing method of the product abandon the manufacturing mode of the reboiler for years, reduce at least six high-difficulty processing procedures, greatly reduce the manufacturing cost and the production and processing difficulty of the reboiler, and have very important significance in the field of manufacturing of the reboiler.

Description

A low-cost built-in reboiler and its manufacturing method

technical field

The invention belongs to the technical field of separation equipment, and in particular relates to a low-cost built-in reboiler and a manufacturing method thereof with a unique concept, which can greatly reduce the manufacturing cost and production difficulty of the reboiler.

Background technique

Reboiler (also known as reboiler) is an important basic chemical equipment. As the application number is 2016109209331, the authorized announcement number is CN107970635B, and the invention name is a fixed tube plate reboiler and its application and distillation method. The Chinese patent introduced in the background technology: reboilers are generally used in petrochemical and chemical synthesis In the rectification and purification process of liquid materials, it is often used in conjunction with a rectification tower. The reboiler is equipped with upper and lower tube sheets, and the tube sheets are densely opened with holes, and heat exchange tubes are welded in the holes. Opening, the space formed between the upper and lower tube sheets is a heating space, and heating medium such as steam is passed through to heat the heat exchange tubes; since the material enters from the material inlet at the lower end of the reboiler, it is filled into the liquid material storage space at the lower end of the reboiler And the heating tube, the material to be vaporized in the heating tube is heated and evaporated, and enters the rectification tower for fractionation. When the reboiler is working, the rectification tower provides the liquid phase from the bottom of the tower into the reboiler, and 25%-30% of the liquid in the reboiler is vaporized, and the vaporized material enters the rectification tower again for circulation rectification.

As shown in Figure 1, the structure of the reboiler mainly includes a cylinder, the upper and lower ends of the cylinder are respectively sealed and welded with an upper tube sheet and a lower tube sheet, and a tube bundle assembly is arranged between the two tube sheets. Among them, the tube bundle assembly includes heat exchange tubes, baffles distributed at intervals, tie rods whose one end is fixedly connected to the upper tube sheet, and the other end is fixedly connected to the end baffles, and distance tubes that play a role of fixing distance. On the top of the upper tube plate is the puppet II assembly which is airtightly connected with it, and the puppet II assembly includes the puppet II and the flange plate which is airtightly connected with it; The head assembly includes the upper head and the flange that is airtightly connected to it; under the lower tube sheet is the puppet I assembly that is airtightly connected to it. Flange; The lower part of the puppet I assembly is the lower cone assembly, which includes the lower cone, the lower cone puppet, and the flange that is airtightly connected to the lower cone puppet. The lower cone is equipped with a lower cone material inlet, a lower cone discharge port, a pup joint material inlet on the lower cone pup joint, a cylinder discharge discharge port, a condensate outlet, and a steam inlet on the cylinder body. A grounding plate is also installed on the barrel, and the pup joint II is equipped with a material outlet.

The reboiler's tube sheet and barrel, as well as the tube sheet and pup joint are airtight and fixed. The airtight connection between the tube sheet and the cylinder, and between the tube sheet and the pup joint of the traditional reboiler is shown in Figure 2-Figure 3, that is, the edges of both ends of the tube sheet are sloped (chamfered) , on the end surface of the cylinder and the end surface of the nipple, the slope surface in the direction opposite to the slope surface of the tube plate is processed. The area between the two slope surfaces is the welding area, and it is filled with solder until it forms the same surface as the surface of the reboiler. The triangular shaded area t1 in Fig. 2 and Fig. 3 represents the filled solder. The reboiler is bulky, and the inner diameter of the cylinder alone reaches 1100mm. All parts of the reboiler are made of metal, most of which are made of q345r alloy steel, and are very heavy. The tube sheet is compatible with the cylinder, and also has the characteristics of large diameter and heavy weight. At present, the slope treatment of the shell, the tube sheet and the end face of the pup joint is realized by the numerical control machine tool. Before the process, the slope processing of the tube sheet is carried out after the tube sheet is cut and formed. It can be seen that the traditional reboiler has many and complicated production processes, high processing difficulty, high processing cost, large equipment investment and high maintenance cost.

Contents of the invention

The object of the present invention is to address the deficiencies in the prior art, and provide a low-cost built-in reboiler and its manufacturing method with a unique concept, which can greatly reduce the manufacturing cost and production difficulty of the reboiler.

The present invention is achieved through the following technical solutions:

A low-cost built-in reboiler, including a cylinder, an upper tube sheet and a lower tube sheet respectively welded to both ends of the cylinder, characterized in that the outer diameter of the upper tube sheet is the same as the inner diameter of the cylinder, and the short joint The inner diameter is equivalent, and the outer diameter of the lower tube plate is equivalent to the inner diameter of the cylinder and the inner diameter of the pup joint I;

The wall thickness of the upper tube sheet is divided into three parts, the first part of the upper tube sheet is embedded in the cylinder body, and the third part of the upper tube sheet is embedded in the pup joint II, which is located between the first part of the upper tube sheet and the upper tube Between the third part of the plate is the second part of the upper tube plate for filling the solder;

The wall thickness of the lower tube sheet is divided into three parts, the first part of the lower tube sheet is embedded in the cylinder body, and the third part of the lower tube sheet is embedded in the pup joint I, which is located between the first part of the lower tube sheet and the lower tube Between the third part of the plate is the second part of the lower tube plate for filling with solder.

Preferably, the thickness of the second part of the upper tube sheet is 1/10-1/6 of the wall thickness of the upper tube sheet; the thickness of the second part of the lower tube sheet is 1/10-1/6 of the wall thickness of the lower tube sheet. The proportion range is determined by considering the structural strength of the product and the difficulty of welding. The welding difficulty is not high, and the welding firmness is guaranteed.

A method for manufacturing a low-cost built-in reboiler, comprising the following steps:

Step a: Pre-assemble and weld the upper head assembly and the lower cone assembly for standby;

Step b: Pre-assemble and weld the sub-section I and sub-section II components for backup;

Step c: Pre-preparing the upper tube sheet and the lower tube sheet with several heat exchange tube through holes; wherein, the outer diameter of the upper tube sheet is equivalent to the inner diameter of the cylinder and the inner diameter of the short joint II, and the outer diameter of the lower tube sheet is equivalent to that of the cylinder The internal diameter and short joint I internal diameter are equivalent;

Step d: Weld temporary lifting lugs for easy lifting at any position on the outer surface of the upper tube plate, place the upper tube plate horizontally on the supporting claw of the welding aid mechanism, and press down the positioning and locking plate of the welding aid mechanism until it is positioned The bottom surface of the locking plate is pressed against the side wall of the upper tube plate; the position where the positioning locking plate is located on the side wall of the upper tube plate is the second part of the upper tube plate;

Step e: install tie rods, distance tubes, and baffles on the upper tube plate of step d;

Step f: use the temporary lifting lugs in step d to lift the product of step e, push the product of step e into the cylinder, push the product of step e into the cylinder until the end surface of the cylinder touches the side of the positioning locking plate To the reference plane, after positioning, spot weld the contact edge seam between the cylinder body and the upper tube plate to realize the pre-fixation of the upper tube plate and the cylinder body;

Step g: Flip the supporting jaws described in step d toward the barrel, remove the temporary lifting lugs in step f, lift the sub-section II assembly, and push the sub-section II assembly in the direction of the upper tube sheet until the short sub-assembly The end face of the section II touches the other lateral reference plane of the positioning locking plate. After the positioning is completed, spot welding is performed on the contact edge between the puppet II and the upper tube sheet to realize the pre-fixation of the upper tube sheet and the pup section II components. ;

Step h: Remove the welding aid mechanism described in step d, perform full welding on the contact edge seam between the cylinder body and the upper tube sheet, perform full welding on the contact edge between the pup joint II and the upper tube sheet, and use Fill the space between the second part of the upper tube sheet and the surface body of the reboiler with solder;

Step i: Weld temporary lifting lugs convenient for lifting at any position on the outer surface of the lower tube plate, place the lower tube plate horizontally on the supporting claw of the welding aid mechanism, and press down the positioning locking plate of the welding aiding mechanism until the positioning lock The bottom surface of the tight plate presses the side wall of the lower tube plate; the position of the positioning locking plate on the side wall of the lower tube plate is the second part of the lower tube plate;

Step j: use the temporary lifting lugs in step i to lift the product of step i, push the lower tube plate from the other end of the cylinder until the end surface of the cylinder touches the lateral reference plane of the positioning locking plate, after positioning Spot welding the contact edge seam between the cylinder body and the lower tube plate to realize the pre-fixation of the lower tube plate and the cylinder body;

Step k: Flip the supporting jaws in step i towards the direction of the shell, remove the temporary lifting lugs in step j, lift the puppet I assembly, and push the puppet I assembly toward the lower tubesheet until the puppet I The end surface is in contact with the other lateral reference plane of the positioning locking plate. After positioning, spot welding is performed on the contact edge between the sub-section I and the lower tube plate to realize the pre-fixation of the lower tube plate and the sub-section I components;

Step 1: Remove the welding aid mechanism described in step i, perform full welding on the contact edge seam between the cylinder body and the lower tube plate, perform full welding on the contact edge between the pup joint I and the lower tube plate, and Use solder to fill up the space between the second part of the lower tube sheet and the surface body of the reboiler;

Step m: assembling welded heat exchange tubes, assembling welding auxiliary accessories;

Step n: install the upper head assembly on the flange of the short joint II; install the lower cone assembly on the flange of the short joint I.

Preferably, the solder in step h and step l is on the same curved surface as the surface body of the reboiler by grinding after filling. The operation method is simple to ensure that the appearance of the product meets the quality inspection requirements.

Preferably, the supporting claw is a component of the supporting assembly of the fluxing mechanism, and the positioning locking plate is a component of the locking and positioning assembly of the fluxing mechanism;

There are multiple supporting components and locking and positioning components, and the two components are regularly distributed in staggered intervals on the tooling ring;

The supporting assembly also includes a supporting lock, the supporting claw is movably connected with the tooling ring, and the supporting claw is flipped in the direction of the pup joint to realize the locking of the supporting claw and the tooling ring by the supporting lock. Relatively fixed;

The locking and positioning assembly also includes a nut seat integrated with the tooling ring, and the nut seat is screwed with an adjusting screw connected with the bearing of the positioning and locking plate. There are two technical difficulties when the upper tube sheet is embedded in the cylinder: 1. How to ensure that the tube sheet is coaxial with the cylinder, that is, to avoid the tube sheet entering the cylinder in a skewed state; 2. The tube sheet embedded in the cylinder How to quickly grasp the depth. The design of the welding aiding mechanism of the present invention is simple and ingenious. The tube plate is supported on the supporting claw, and the pressing force between the positioning locking plate and the tube plate is controlled by adjusting the screw, and the contact area between the positioning locking plate and the tube plate is controlled. That is, the position of the second part of the tube sheet is positioned, and the two sides of the positioning locking plate are the first part of the tube sheet and the third part of the tube sheet, so that the positioning of the locking plate naturally determines the three parts of the side wall of the tube sheet. The coaxial line is guaranteed, and the embedded depth is determined. The structure is simple, the concept is ingenious, and the operation is convenient and simple. The supporting claw is designed to be reversible and movable, so as to avoid hindering the subsequent installation of the pup joint.

Preferably, the end side of the supporting claw is provided with a support nozzle adapted to the edge of the tube sheet, and the end side of the supporting claw is also provided with a lateral reference surface in contact with the end surface of the cylinder. The support nozzle fits perfectly with the edge of the tube sheet, and the support nozzle supports the tube sheet to ensure that the tube sheet is horizontally still in the fluxing mechanism, which also ensures the positioning accuracy of the positioning locking plate after pressing down; the end of the supporting claw The lateral datum plane on the side plays a certain auxiliary role. Together with the positioning and locking plate, it is in contact with the end surface of the cylinder. Assuming that the cylinder hits the fluxing mechanism during the assembly process, the supporting claws can play a certain buffer at this time. function, to avoid the positioning and locking plate from being displaced due to excessive instantaneous stress. This small detail design helps to improve the stability of the fluxing mechanism.

Preferably, the support assembly further includes a compression lock, and the support lock and the compression lock are respectively arranged on two opposite sides of the tooling ring;

After the supporting claws are flipped in place towards the cylinder, the pressing lock is used to realize that the supporting claws apply a compressive force to the cylinder;

The bottom surface of the end of the supporting claw is fixed with a rubber liner which is convenient for the supporting claw to press the cylinder body. The structural design of the combination of the compression lock and the supporting claws can enhance the stability of the welding mechanism. After the supporting claws are turned over, the rubber pads of the supporting claws gradually approach the cylinder body. When the supporting claws When the lock is pressed and locked, the rubber gasket is tightly squeezed against the barrel, thereby further enhancing the installation firmness of the welding aid mechanism and the barrel. Even if the short joint hits the positioning and locking plate, the positioning and locking plate will not Will not shift.

Preferably, both the support lock and the compression lock adopt a quick-release screw structure, including a connecting rod connected to the tooling ring bearing, the wrench is eccentrically movable connected with the head of the connecting rod, and the connecting rod is covered with a pressing piece , a compression spring is provided between the pressing piece and the tooling ring, the head of the wrench is provided with a raised ridge along the contour of the head, and the pressing piece is provided with a stroke groove matching the raised ridge;

The middle position of the supporting claw is provided with a central keyhole matching the supporting buckle;

Both sides of the supporting claw are fixedly provided with fins, and the fins are provided with side keyholes matched with the compression lock. The structural design of this scheme is also ingenious, and some improvements are made to the existing quick-release screw structure. The simple structural improvement enables the pressing piece to follow the rotation of the wrench, and at the same time, it does not affect the turning movement of the wrench relative to the pressing piece.

Preferably, the back side of the positioning and locking plate is provided with a slider that slides along a chute, and the chute is provided on the tooling ring and opened along the radial direction of the tooling ring. The chute is a T-slot, and the design of the slider and the chute ensures that the positioning locking plate slides without shaking, ensuring the positioning accuracy of the positioning locking plate.

Preferably, the positioning and locking plate includes an end positioning plate for reference positioning and a main body plate for enhancing structural strength. The end surfaces on both sides of the end positioning plate are lateral reference planes. The transitional connection is made through a transition plate with a trapezoidal cross-section. The height of the end positioning plate must be greater than the thickness of the cylinder. This solution is designed taking into account the operability and mechanical strength of the positioning locking plate.

Compared with prior art, the beneficial effect of the present invention is:

The invention changes the assembly method of the traditional reboiler tube sheet, designs the tube sheet as an embedded type, and defines the side wall of the tube sheet into three parts; in the axial direction of the tube sheet, a part of the tube sheet is embedded in the cylinder, and a part of the tube sheet It is embedded in the pup joint, and the side wall of the tube sheet in the middle part and the surface body of the reboiler naturally form a certain space, and this space can just constitute the solder filling area, and there is no need for slope processing in order to fully seal the welding, reducing the cylinder body Many difficult and high-cost production and processing procedures, such as slope surface processing, nipple slope surface processing, and tube sheet slope surface processing, do not need to be equipped with corresponding CNC machine tools and related technical personnel, which greatly reduces the production difficulty and cost of the reboiler. manufacturing cost;

The biggest technical problems after the present invention is changed to the embedded assembly method are: 1. How to ensure the coaxial line between the embedded tube sheet and the cylinder (pup joint); 2. How to quickly determine the embedded depth of the tube sheet. The invention ingeniously designs the welding aid mechanism, which can position the side wall of the tube sheet into three parts at one time, and take the two sides of the positioning locking plate as the reference plane, which not only ensures the coaxial line, but also quickly determines the embedded depth. Realized the "fast, straight and accurate" assembly of the cylinder, pup joint and tube sheet;

The product structure improvement and manufacturing method of the present invention abandon the reboiler manufacturing method that lasted for several years, simplify at least six difficult processing procedures, and greatly reduce the reboiler manufacturing cost and production and processing difficulty, which has great advantages in the field of reboiler manufacturing. Significance.

Description of drawings

Figure 1 is a schematic diagram of the structure of a traditional reboiler.

Fig. 2 is an enlarged view of A1 in Fig. 1 of the present invention.

Fig. 3 is an enlarged view of A2 in Fig. 1 of the present invention.

Fig. 4 is a schematic structural diagram of the reboiler of the present invention.

Fig. 5 is an enlarged view of B1 in Fig. 4 of the present invention.

Fig. 6 is an enlarged view of B2 in Fig. 4 of the present invention.

Fig. 7 is a schematic diagram of the structure when the upper tube plate of the present invention cooperates with the cylinder body and the pup joint II (unwelded).

Fig. 8 is a structural schematic diagram (unwelded) when the lower tube plate of the present invention cooperates with the cylinder body and the pup joint I.

Fig. 9 is a schematic diagram of the application structure of the fluxing mechanism of the present invention in the manufacturing process of the reboiler.

FIG. 10 is a first schematic view of the three-dimensional structure in FIG. 9 of the present invention.

Fig. 11 is a partially enlarged view of Fig. 10 of the present invention.

Fig. 12 is a second schematic view of the structure in the perspective direction of Fig. 9 of the present invention.

Fig. 13 is a schematic view of the front structure of the soldering mechanism of the present invention.

Fig. 14 is a cross-sectional view along line E-E of Fig. 13 of the present invention.

Fig. 15 is a partially enlarged view of Fig. 14 of the present invention.

Fig. 16 is a schematic diagram of the rear structure of the welding fluxing mechanism of the present invention.

Fig. 17 is a schematic view of the three-dimensional structure of the fluxing mechanism of the present invention.

Fig. 18 is a partially enlarged view of Fig. 17 of the present invention.

Fig. 19 is a schematic structural view of the supporting claws of the supporting assembly of the present invention.

In the figure: 1. Upper head assembly; 11. Upper head; 2. Lower cone assembly; 21. Lower cone; 22. Lower cone material inlet; 23. Short joint material inlet; 24. Lower cone Net port; 25, lower cone pup joint; 3, pup joint I component; 31, pup joint I; 4, pup joint II component; 41, pup joint II; 42, material outlet; 51, upper tube plate; 511, The first part of the upper tube sheet; 512, the second part of the upper tube sheet; 513, the third part of the upper tube sheet; 52, the lower tube sheet; 521, the first part of the lower tube sheet; 522, the second part of the lower tube sheet; 523, the lower tube sheet The third part of the tube sheet; 53, cylinder; 531, steam inlet; 532, cylinder drain outlet; 533, condensate outlet; 534, grounding plate; 54, tie rod; 55, distance tube; 56, baffle ;57. Heat exchange tube; 6. Welding mechanism; 61. Supporting component; 611. Supporting claw; 6111. Center keyhole; 6112. Fin plate; 6113. Side keyhole; 6114. Supporting mouth; , rubber gasket; 612, supporting lock; 6121, connecting rod; 6122, wrench; 6123, pressure sheet; 6124, compression spring; 6125, raised ridge; 6126, stroke groove; Locking positioning assembly; 621, positioning locking plate; 6211, end positioning plate; 6212, main body plate; 6213, transition plate; 6214, slider; 622, nut seat; chute; 7, lateral reference plane.

Detailed ways

Below in conjunction with accompanying drawing, the present invention is further described:

In order to enable readers to better understand the design purpose of the present invention, the technical solution of the present invention will be further described below in conjunction with the embodiments. It should be noted that the orientation nouns that may be involved in the following paragraphs, including but not limited to "up, down, left, right, front, back", etc., are based on the visual orientations shown in the corresponding drawings. , which should not and should not be regarded as limiting the protection scope or technical solutions of the present invention, and its purpose is only to facilitate those skilled in the art to better understand the technical solutions described in the present invention.

In the description of this manual, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

Example 1

As shown in Figures 4 to 8, a low-cost built-in reboiler includes a cylinder 53, an upper tube sheet 51 and a lower tube sheet 52 welded to both ends of the cylinder 53, and the outer diameter of the upper tube sheet 51 is It is equivalent to the inner diameter of the cylinder body 53 and the inner diameter of the pup joint II41, and the outer diameter of the lower tube plate 52 is equivalent to the inner diameter of the cylinder body 53 and the inner diameter of the pup joint I31;

The wall thickness of the upper tube plate 51 is divided into three parts, the first part 511 of the upper tube plate embedded in the cylinder body 53, the third part 513 of the upper tube plate embedded in the short joint II41, located in the first part 511 of the upper tube plate Between the third part of the upper tube plate 513 is the second part of the upper tube plate 512 for filling solder; the wall thickness of the lower tube plate 52 is divided into three parts, and the part embedded in the cylinder body 53 is the first part of the lower tube plate 521, the third part of the lower tube plate 523 is embedded in the short joint I31, and the second part of the lower tube plate 522 for filling solder is located between the first part of the lower tube plate 521 and the third part of the lower tube plate 523. The rectangular shaded area t2 in Fig. 5 and Fig. 6 represents the filled solder.

Wherein, the thickness of the second part 512 of the upper tube plate is 1/10-1/6 of the wall thickness of the upper tube plate 51 ; the thickness of the second part 522 of the lower tube plate is 1/10-1/6 of the wall thickness of the lower tube plate 52 . The proportion range is determined by considering the structural strength of the product and the difficulty of welding. The welding difficulty is not high, and the welding firmness is guaranteed.

In this embodiment, a part of the upper tube plate 51 is embedded in the cylinder body 53 and a part is embedded in the short joint I31. Similarly, a part of the lower tube plate 52 is embedded in the cylinder body 53 and a part is embedded in the short joint II41. The invention changes the assembly method of the traditional reboiler tube sheet, designs the tube sheet as an embedded type, and defines the side wall of the tube sheet into three parts; in the axial direction of the tube sheet, a part of the tube sheet is embedded in the cylinder, and a part of the tube sheet It is embedded in the pup joint, and the side wall of the tube sheet in the middle part and the surface body of the reboiler naturally form a certain space, and this space can just constitute the solder filling area, and there is no need for slope processing in order to fully seal the welding, reducing the cylinder body Many difficult and high-cost production and processing procedures, such as slope surface processing, nipple slope surface processing, and tube sheet slope surface processing, do not need to be equipped with corresponding CNC machine tools and related technical personnel, which greatly reduces the production difficulty and cost of the reboiler. manufacturing cost.

Example 2

As shown in Figures 4 to 12, this embodiment provides a manufacturing method for the low-cost built-in reboiler in Embodiment 1, including the following steps:

Step a: Pre-assemble and weld the upper head assembly 1 and the lower cone assembly 2 for standby;

Step b: Pre-assemble and weld the sub-joint I component 3 and the sub-joint II component 4 for standby; of course, in order to facilitate the disassembly of the soldering mechanism 6, the material outlet 42 of the sub-joint II component 4 is not installed here, and the material outlet 42 assembled in step m;

Step c: prepare in advance the upper tube sheet 51 and the lower tube sheet 52 with several heat exchange tube through holes; wherein, the outer diameter of the upper tube sheet 51 is equivalent to the inner diameter of the cylinder body 53 and the inner diameter of the pup joint II41, and the lower tube sheet 52 The outer diameter is equivalent to the inner diameter of the cylinder body 53 and the inner diameter of the pup joint I31;

Step d: Weld temporary lifting lugs convenient for lifting at any position on the outer surface of the upper tube plate 51, and the temporary lifting lugs are generally welded on the peripheral position of the tube plate; place the upper tube plate 51 horizontally on the supporting jaws of the welding aid mechanism 6 611, press down the positioning locking plate 621 of the welding aid mechanism 6 until the bottom surface of the positioning locking plate 621 is pressed against the side wall of the upper tube plate 51; the position where the positioning locking plate 621 is positioned on the side wall of the upper tube plate 51 It is the second part 512 of the upper tube plate; the positioning and locking plate 621 moves along the radial direction of the upper tube plate 51 until it is pressed against the upper tube plate 51, at this time the fluxing mechanism 6 and the upper tube plate 51 are fixed together, and the positioning is locked The position determined by the plate 621 on the upper tube plate 51 is the second part 512 of the upper tube plate, and the two sides of the positioning and locking plate 621 are respectively the first part of the tube plate and the third part of the tube plate, so that the positioning and locking plate 621 Naturally, the three parts of the side wall of the tube sheet are determined.

Step e: install pull rod 54, spacer pipe 55, baffle plate 56 on the upper tube plate 51 of step d;

Step f: Use the temporary lifting lugs in step d to lift the product of step e, push the product of step e into the cylinder 53, push the product of step e into the cylinder 53 until the end surface of the cylinder 53 touches the positioning and locking plate The lateral reference plane 7 of 621, after positioning, spot-weld the contact seam between the cylinder body 53 and the upper tube plate 51 to realize the pre-fixation of the upper tube plate 51 and the cylinder body 53;

Step g: Flip the supporting claw 611 of step d towards the direction of the cylinder body 53, remove the temporary lifting lug in step f, lift the puppet II assembly 4, and push the puppet II assembly 4 toward the upper tube plate 51 until The end face of the puppet II41 touches the other lateral reference plane 7 of the positioning locking plate 621. After positioning, spot welding is performed on the contact edge between the puppet II41 and the upper tube plate 51 to realize the connection between the upper tube plate 51 and the puppet. Prefixation of II component 4;

Step h: remove the welding aid mechanism 6 in step d, perform full welding on the contact edge seam between the cylinder body 53 and the upper tube plate 51, and perform full welding on the contact edge between the pup joint II41 and the upper tube plate 51, And use solder to completely fill the space between the second part 512 of the upper tube sheet and the surface body of the reboiler;

Step i: Weld temporary lifting lugs convenient for lifting at any position on the outer surface of the lower tube plate 52, place the lower tube plate 52 horizontally on the supporting claw 611 of the welding aid mechanism 6, and press down the positioning and locking of the welding aid mechanism 6 plate 621 until the bottom surface of the positioning locking plate 621 presses the side wall of the lower tube plate 52; the position where the positioning locking plate 621 is positioned on the side wall of the lower tube plate 52 is the second part 522 of the lower tube plate; this step and step d works the same way.

Step j: Use the temporary lifting lugs in step i to lift the product of step i, push the lower tube plate 52 from the other end of the cylinder body 53 until the end surface of the cylinder body 53 touches the lateral reference plane 7 of the positioning locking plate 621, After positioning, spot welding is performed on the contact edge seam between the cylinder body 53 and the lower tube plate 52 to realize the pre-fixation of the lower tube plate 52 and the cylinder body 53;

Step k: Flip the supporting jaw 611 in step i toward the cylinder body 53, remove the temporary lifting lug in step j, lift the puppet I assembly 3, and push the puppet I assembly 3 in the direction of the lower tube plate 52 Until the end surface of the short joint I31 touches the other lateral reference plane 7 of the positioning locking plate 621, spot welding is performed on the contact edge between the short joint I31 and the lower tube plate 52 after the positioning is completed, so as to realize the connection between the lower tube plate 52 and the short joint. Prefixation of Section I Component 3;

Step 1: Remove the welding aid mechanism 6 in step i, perform full welding on the contact edge seam between the cylinder body 53 and the lower tube plate 52, and perform full welding on the contact edge between the pup joint I31 and the lower tube plate 52 , and use solder to completely fill the space between the second part 522 of the lower tube plate and the surface body of the reboiler;

Step m: assembling welding heat exchange tube 57, assembling welding auxiliary fittings; the auxiliary fittings of this embodiment refer to other conventional fittings of the reboiler, such as including the material outlet 42, and the steam inlet 531 arranged on the cylinder body, the cylinder body putting Net port 532, condensate outlet 533, grounding plate 534, etc.;

Step n: Install the upper head assembly 1 on the flange of the pup joint II41; install the lower cone assembly 2 on the flange of the pup joint I31; the upper head assembly in this embodiment includes the upper head 11, and the upper The flange plate fixed to the head; the lower cone assembly includes the lower cone 21, the lower cone sub-joint 25, the flange fixed to the lower cone, and the lower cone material inlet arranged on the lower cone 21 22. The pup joint material inlet 23 and the lower cone discharge port 24.

After the solder in step h and step l is filled, it is on the same curved surface as the surface body of the reboiler by grinding. The operation method is simple to ensure that the appearance of the product meets the quality inspection requirements.

The invention changes the assembly method of the traditional reboiler tube sheet, designs the tube sheet as an embedded type, and defines the side wall of the tube sheet into three parts; in the axial direction of the tube sheet, a part of the tube sheet is embedded in the cylinder, and a part of the tube sheet It is embedded in the pup joint, and the side wall of the tube sheet in the middle part and the surface body of the reboiler naturally form a certain space, and this space can just constitute the solder filling area, and there is no need for slope processing in order to fully seal the welding, reducing the cylinder body Many difficult and high-cost production and processing procedures, such as slope surface processing, nipple slope surface processing, and tube sheet slope surface processing, do not need to be equipped with corresponding CNC machine tools and related technical personnel, which greatly reduces the production difficulty and cost of the reboiler. manufacturing cost;

The biggest technical problem after the present invention is changed to the embedded assembly method is: 1. How to ensure that the embedded tube sheet is coaxial with the cylinder (short joint), and the skewed assembly will directly affect the subsequent heat exchange tube 57. The interspersed process will cause the heat exchange tube 57 to fail to be inserted smoothly, and will also affect the subsequent joint sealing welding, which plays a vital role in product quality; 2. How to quickly determine the embedment depth of the tube sheet. The invention ingeniously designs the welding aid mechanism, which can position the side wall of the tube sheet into three parts at one time, and take the two sides of the positioning locking plate as the reference plane, which not only ensures the coaxial line, but also quickly determines the embedded depth. Realized the "fast, straight and accurate" assembly of the barrel, pup joints and tube sheets; The pipe wall distance is accurate.

The product structure improvement and manufacturing method of the present invention abandon the reboiler manufacturing method that lasted for several years, simplify at least six difficult processing procedures, and greatly reduce the reboiler manufacturing cost and production and processing difficulty, which has great advantages in the field of reboiler manufacturing. Significance.

Example 3

On the basis of Embodiment 2, the present invention continues to describe in detail the technical features involved in it and the functions and effects played by the technical features in the present invention, so as to help those skilled in the art fully understand the present invention. technical solutions and reproduce them.

This embodiment provides a method for manufacturing a low-cost built-in reboiler, including the following steps:

Step a: Pre-assemble and weld the upper head assembly 1 and the lower cone assembly 2 for standby;

Step b: Pre-assemble and weld the pup joint I component 3 and pup joint II component 4 for standby;

Step c: prepare in advance the upper tube sheet 51 and the lower tube sheet 52 with several heat exchange tube through holes; wherein, the outer diameter of the upper tube sheet 51 is equivalent to the inner diameter of the cylinder body 53 and the inner diameter of the pup joint II41, and the lower tube sheet 52 The outer diameter is equivalent to the inner diameter of the cylinder body 53 and the inner diameter of the pup joint I31;

Step d: Weld temporary lifting lugs convenient for lifting at any position on the outer surface of the upper tube plate 51, place the upper tube plate 51 horizontally on the supporting claw 611 of the welding aid mechanism 6, and press down the positioning lock of the welding aid mechanism 6 Tighten the plate 621 until the bottom surface of the positioning locking plate 621 presses the side wall of the upper tube plate 51; the position where the positioning locking plate 621 is positioned on the side wall of the upper tube plate 51 is the second part 512 of the upper tube plate; the positioning lock The tightening plate 621 moves along the radial direction of the upper tube plate 51 until it presses the upper tube plate 51. At this time, the welding aid mechanism 6 and the upper tube plate 51 are fixed together, and the position determined by the locking plate 621 on the upper tube plate 51 is fixed. It is the second part 512 of the upper tube sheet, and the two sides of the positioning locking plate 621 are respectively the first part of the tube sheet and the third part of the tube sheet, so that the positioning locking plate 621 naturally determines the three parts of the side wall of the tube sheet good.

Step e: install pull rod 54, spacer pipe 55, baffle plate 56 on the upper tube plate 51 of step d;

Step f: Use the temporary lifting lugs in step d to lift the product of step e, push the product of step e into the cylinder 53, push the product of step e into the cylinder 53 until the end surface of the cylinder 53 touches the positioning and locking plate The lateral reference plane 7 of 621, after positioning, spot-weld the contact seam between the cylinder body 53 and the upper tube plate 51 to realize the pre-fixation of the upper tube plate 51 and the cylinder body 53;

Step g: Flip the supporting claw 611 of step d towards the direction of the cylinder body 53, remove the temporary lifting lug in step f, lift the puppet II assembly 4, and push the puppet II assembly 4 toward the upper tube plate 51 until The end face of the puppet II41 touches the other lateral reference plane 7 of the positioning locking plate 621. After positioning, spot welding is performed on the contact edge between the puppet II41 and the upper tube plate 51 to realize the connection between the upper tube plate 51 and the puppet. Prefixation of II component 4;

Step h: remove the welding aid mechanism 6 in step d, perform full welding on the contact edge seam between the cylinder body 53 and the upper tube plate 51, and perform full welding on the contact edge between the pup joint II41 and the upper tube plate 51, And use solder to completely fill the space between the second part 512 of the upper tube sheet and the surface body of the reboiler;

Step i: Weld temporary lifting lugs convenient for lifting at any position on the outer surface of the lower tube plate 52, place the lower tube plate 52 horizontally on the supporting claw 611 of the welding aid mechanism 6, and press down the positioning and locking of the welding aid mechanism 6 plate 621 until the bottom surface of the positioning locking plate 621 presses the side wall of the lower tube plate 52; the position where the positioning locking plate 621 is positioned on the side wall of the lower tube plate 52 is the second part 522 of the lower tube plate; this step and step d works the same way.

Step j: Use the temporary lifting lugs in step i to lift the product of step i, push the lower tube plate 52 from the other end of the cylinder body 53 until the end surface of the cylinder body 53 touches the lateral reference plane 7 of the positioning locking plate 621, After positioning, spot welding is performed on the contact edge seam between the cylinder body 53 and the lower tube plate 52 to realize the pre-fixation of the lower tube plate 52 and the cylinder body 53;

Step k: Flip the supporting jaw 611 in step i toward the cylinder body 53, remove the temporary lifting lug in step j, lift the puppet I assembly 3, and push the puppet I assembly 3 in the direction of the lower tube plate 52 Until the end surface of the short joint I31 touches the other lateral reference plane 7 of the positioning locking plate 621, spot welding is performed on the contact edge between the short joint I31 and the lower tube plate 52 after the positioning is completed, so as to realize the connection between the lower tube plate 52 and the short joint. Prefixation of Section I Component 3;

Step 1: Remove the welding aid mechanism 6 in step i, perform full welding on the contact edge seam between the cylinder body 53 and the lower tube plate 52, and perform full welding on the contact edge between the pup joint I31 and the lower tube plate 52 , and use solder to completely fill the space between the second part 522 of the lower tube plate and the surface body of the reboiler;

Step m: assembling welding heat exchange tube 57, assembling welding auxiliary fittings; the auxiliary fittings of this embodiment refer to other conventional fittings of the reboiler, such as including the material outlet 42, and the steam inlet 531 arranged on the cylinder body, the cylinder body putting Net port 532, condensate outlet 533, grounding plate 534, etc.;

Step n: Install the upper head assembly 1 on the flange of the pup joint II41; install the lower cone assembly 2 on the flange of the pup joint I31; the upper head assembly in this embodiment includes the upper head 11, and the upper The flange plate fixed to the head; the lower cone assembly includes the lower cone 21, the lower cone sub-joint 25, the flange fixed to the lower cone, and the lower cone material inlet arranged on the lower cone 21 22. The pup joint material inlet 23 and the lower cone discharge port 24.

As shown in Figures 13 to 19, the supporting claw 611 of this embodiment is a part of the supporting assembly 61 of the welding aid mechanism 6, and the positioning locking plate 621 is a part of the locking and positioning assembly 62 of the welding aiding mechanism 6; the supporting assembly 61. Multiple locking and positioning assemblies 62 are provided, and the two assemblies are regularly distributed in staggered intervals on the tooling ring 63; the supporting component 61 also includes a supporting lock 612, and the supporting claws 611 are movably connected with the tooling ring 63. After the supporting claw 611 is flipped in place toward the pup joint direction, the supporting claw 611 and the tooling ring 63 are relatively fixed by the supporting lock 612 . The locking and positioning assembly 62 also includes a nut seat 622 integrated with the tooling ring 63 , and the nut seat 622 is screwed with an adjusting screw 623 bearingly connected with the positioning and locking plate 621 . The support assembly 61 supports the tube sheet, and after the support assembly 61 and the tooling ring 63 are relatively fixed, the tube sheet is horizontally placed on the support assembly 61, and the plane of the tube sheet and the plane of the fluxing mechanism 6 are parallel to each other; , it can ensure that the position of the positioning locking plate 621 moving along the radial direction of the tube sheet on the side wall of the tube sheet is accurate.

There are two technical difficulties when the upper tube sheet is embedded in the cylinder: 1. How to ensure that the tube sheet is coaxial with the cylinder, that is, to avoid the tube sheet entering the cylinder in a skewed state; 2. The tube sheet embedded in the cylinder How to quickly grasp the depth. The design of the welding aiding mechanism of the present invention is simple and ingenious. The tube plate is supported on the supporting claw, and the pressing force between the positioning locking plate and the tube plate is controlled by adjusting the screw, and the contact area between the positioning locking plate and the tube plate is controlled. That is, the position of the second part of the tube sheet is positioned, and the two sides of the positioning locking plate are the first part of the tube sheet and the third part of the tube sheet, so that the positioning of the locking plate naturally determines the three parts of the side wall of the tube sheet. The coaxial line is guaranteed, and the embedded depth is determined, the structure is simple, the concept is ingenious, and the operation is convenient and simple. The supporting jaws are designed to be reversible and movable, so as to avoid obstruction to the subsequent sub-joint installation.

In this embodiment, the end side of the supporting claw 611 is provided with a support nozzle 6114 adapted to the edge of the tube sheet, and the end side of the supporting claw 611 is also provided with a lateral reference surface 7 in contact with the end surface of the cylinder 53 . The support nozzle fits perfectly with the edge of the tube sheet, and the support nozzle supports the tube sheet to ensure that the tube sheet is horizontally still in the fluxing mechanism, which also ensures the positioning accuracy of the positioning locking plate after pressing down; the end of the supporting claw The lateral datum plane on the side plays a certain auxiliary role. Together with the positioning and locking plate, it is in contact with the end surface of the cylinder. Assuming that the cylinder hits the fluxing mechanism during the assembly process, the supporting claws can play a certain buffer at this time. function, to avoid the positioning and locking plate from being displaced due to excessive instantaneous stress. This small detail design helps to improve the stability of the fluxing mechanism.

The support assembly 61 of this embodiment also includes a compression lock 613, and the support lock 612 and the compression lock 613 are respectively arranged on two opposite sides of the tooling ring 63; After being put in place, the supporting claw 611 exerts a pressing force on the cylinder body 53 by pressing the locking buckle 613; the bottom surface of the end of the supporting claw 611 is fixed with a rubber gasket 6115 for the supporting claw 611 to press the cylinder body 53 . The structural design of the combination of the compression lock and the supporting claws can enhance the stability of the welding mechanism. After the supporting claws are turned over, the rubber pads of the supporting claws gradually approach the cylinder body. When the supporting claws When the lock is pressed and locked, the rubber gasket is tightly squeezed against the barrel, thereby further enhancing the installation firmness of the welding aid mechanism and the barrel. Even if the short joint hits the positioning and locking plate, the positioning and locking plate will not Will not shift.

In this embodiment, the support lock 612 and the compression lock 613 all adopt quick-release screw structures, including the connecting rod 6121 connected to the tooling ring 63 bearings, the wrench 6122 is eccentrically connected with the head of the connecting rod 6121, and the connecting rod 6121 There is a pressing piece 6123 on the top, and a compression spring 6124 is set between the pressing piece 6123 and the tooling ring 63. The head of the wrench 6122 is provided with a raised ridge 6125 along the contour of the head, and the pressing piece 6123 is provided with a raised ridge 6125. The stroke groove 6126; the middle position of the supporting claw 611 is provided with a central keyhole 6111 that is compatible with the supporting lock 612; There are side keyholes 6113 adapted to the compression lock 613 . The structural design of this scheme is also ingenious, and some improvements are made to the existing quick-release screw structure. The simple structural improvement enables the pressing piece to follow the rotation of the wrench, and at the same time, it does not affect the turning movement of the wrench relative to the pressing piece. The angle of the pressing piece 6123 determines whether it interferes with the central keyhole 6111 and the side keyhole 6113. Only when the pressing piece 6123 does not interfere with the keyhole, can the supporting claw 611 not interfere with the buckle. Turn the wrench 6122. The rotation angle of the two assemblies of the wrench 6122 and the pressure piece 6123 can be adjusted. When the angle of the pressing piece 6123 is properly adjusted, turn over the wrench 6122. The wrench 6122 is set eccentrically. The distance between the pressing piece 6123 and 63 is different in different flipping positions, so that the supporting claw 611 is unlocked when it needs to be unlocked. , to be locked when it needs to be locked.

In this embodiment, the back side of the positioning and locking plate 621 is provided with a slider 6214 that slides along the sliding groove 631 . The sliding groove 631 is arranged on the tooling ring 63 and opened along the radial direction of the tooling ring 63 . The chute is a T-slot, and the design of the slider and the chute ensures that the positioning locking plate slides without shaking, ensuring the positioning accuracy of the positioning locking plate.

In this embodiment, the positioning locking plate 621 includes an end positioning plate 6211 for reference positioning and a main body plate 6212 for enhancing structural strength. The end positioning plates 6211 are transitionally connected through a transition plate 6213 with a trapezoidal cross section. In this solution, the height of the end positioning plate must be greater than the thickness of the cylinder. The end positioning plate 6211, the main body plate 6212, and the transition plate 6213 are integrated, and the end surface of the end positioning plate 6211 is in an arc shape that matches the tube plate. This solution is designed taking into account the operability and mechanical strength of the positioning locking plate.

In summary, it is only a preferred embodiment of the present invention, and is not used to limit the scope of the present invention. All equivalent changes and modifications made in accordance with the shape, structure, characteristics and spirit of the scope of the claims of the present invention shall include within the scope of the claims of the present invention.

Claims (8)

1. A method for manufacturing a low-cost built-in reboiler, characterized in that it comprises the following steps: Step a: Pre-assemble and weld the upper head assembly and the lower cone assembly for standby; Step b: Pre-assemble and weld the sub-section I and sub-section II components for backup; Step c: Pre-preparing the upper tube sheet and the lower tube sheet with a number of through holes for heat exchange tubes; wherein, the outer diameter of the upper tube sheet is equivalent to the inner diameter of the cylinder and the inner diameter of the pup joint II, and the outer diameter of the lower tube sheet is equal to that of the cylinder The internal diameter and short joint I internal diameter are equivalent; Step d: Weld temporary lifting lugs at any position on the outer surface of the upper tube plate for easy lifting, place the upper tube plate horizontally on the supporting jaws of the welding aid mechanism, and press down the positioning and locking plate of the welding aiding mechanism until it is positioned The bottom surface of the locking plate is pressed against the side wall of the upper tube plate; the position where the positioning locking plate is positioned on the side wall of the upper tube plate is the second part of the upper tube plate; Step e: Install tie rods, distance tubes and baffles on the upper tube plate of step d; Step f: Use the temporary lifting lugs in step d to lift the product of step e, push the product of step e into the cylinder, and push the product of step e into the cylinder until the end surface of the cylinder touches the side of the positioning locking plate To the reference plane, after positioning, spot weld the contact edge seam between the cylinder body and the upper tube plate to realize the pre-fixation of the upper tube plate and the cylinder body; Step g: Flip the supporting jaws described in step d toward the barrel, remove the temporary lifting lugs in step f, lift the puppet II assembly, and push the puppet II assembly toward the upper tube sheet until the short The end face of the section II touches the other lateral reference plane of the positioning locking plate. After the positioning is completed, spot welding is performed on the contact edge between the puppet II and the upper tube sheet to realize the pre-fixation of the upper tube sheet and the pup section II components. ; Step h: remove the welding aid mechanism described in step d, perform full welding on the contact edge seam between the cylinder body and the upper tube sheet, perform full welding on the contact edge between the pup joint II and the upper tube sheet, and use Fill the space between the second part of the upper tube sheet and the surface body of the reboiler with solder; Step i: Weld temporary lifting lugs for easy lifting at any position on the outer surface of the lower tube plate, place the lower tube plate horizontally on the supporting claw of the welding aid mechanism, and press down the positioning and locking plate of the welding aiding mechanism until the positioning lock The bottom surface of the tightening plate presses the side wall of the lower tube plate; the position of the positioning locking plate on the side wall of the lower tube plate is the second part of the lower tube plate; Step j: Use the temporary lifting lugs in step i to lift the product of step i, push the lower tube plate from the other end of the cylinder until the end surface of the cylinder touches the lateral reference plane of the positioning locking plate, after positioning Spot welding the contact edge seam between the cylinder body and the lower tube plate to realize the pre-fixation of the lower tube plate and the cylinder body; Step k: Flip the supporting jaws in step i toward the barrel, remove the temporary lifting lugs in step j, lift the puppet I assembly, and push the puppet I assembly toward the lower tubesheet until the end of the puppet I The end surface is in contact with the other lateral reference plane of the positioning locking plate. After positioning, spot welding is performed on the contact edge between the sub-section I and the lower tube plate to realize the pre-fixation of the lower tube plate and the sub-section I components; Step 1: Remove the fluxing mechanism described in step i, perform full welding on the contact edge seam between the cylinder body and the lower tube plate, perform full welding on the contact edge between the pup joint I and the lower tube plate, and Use solder to fill up the space between the second part of the lower tube sheet and the surface body of the reboiler; Step m: assembling welded heat exchange tubes and welding auxiliary accessories; Step n: install the upper head assembly on the flange of the short joint II; install the lower cone assembly on the flange of the short joint I. 2. The manufacturing method of a low-cost built-in reboiler according to claim 1, characterized in that: after the solder in the step h and step 1 is filled, it is connected to the surface of the reboiler by grinding body on the same surface. 3. The manufacturing method of a low-cost built-in reboiler according to claim 1, wherein the supporting claw is a part of the supporting assembly of the fluxing mechanism, and the positioning lock The tightening plate is a part of the locking and positioning assembly of the fluxing mechanism; There are multiple supporting components and locking and positioning components, and the two components are regularly distributed in staggered intervals on the tooling ring; The supporting assembly also includes a supporting lock, the supporting claw is movably connected with the tooling ring, and the supporting claw is flipped in the direction of the pup joint to realize the locking of the supporting claw and the tooling ring by the supporting lock. Relatively fixed; The locking and positioning assembly also includes a nut seat integrated with the tooling ring, and the nut seat is screwed with an adjusting screw connected with the bearing of the positioning and locking plate. 4. The manufacturing method of a low-cost built-in reboiler according to claim 3, characterized in that: the end side of the supporting claw is provided with a supporting nozzle adapted to the edge of the tube sheet, so that The end side of the supporting claw is also provided with a lateral reference surface in contact with the end surface of the cylinder. 5. The manufacturing method of a low-cost built-in reboiler according to claim 3, characterized in that: the supporting assembly also includes a compression lock, and the support lock and the compression lock respectively arranged on two opposite sides of the tooling ring; After the supporting claws are flipped in place towards the cylinder, the pressing lock is used to realize that the supporting claws apply a compressive force to the cylinder; The bottom surface of the end of the supporting claw is fixed with a rubber liner which is convenient for the supporting claw to press the cylinder body. 6. The manufacturing method of a low-cost built-in reboiler according to claim 5, characterized in that: the support lock and the compression lock adopt quick-release screw structures, including bearings with tooling rings The connected connecting rod, the wrench is eccentrically movable connected with the head of the connecting rod, the connecting rod is covered with a pressing piece, a compression spring is arranged between the pressing piece and the tooling ring, and the head of the wrench is arranged along the contour of the head. There is a raised ridge, and the pressing piece is provided with a stroke groove matching the raised ridge; The middle position of the supporting claw is provided with a central keyhole matching the supporting buckle; Both sides of the supporting claw are fixedly provided with fins, and the fins are provided with side keyholes matched with the compression lock. 7. The manufacturing method of a low-cost built-in reboiler according to claim 3, characterized in that: the back of the positioning locking plate is provided with a slider that slides along a chute, and the chute is set On the tooling ring, it is set along the radial direction of the tooling ring. 8. The manufacturing method of a low-cost built-in reboiler according to claim 3, characterized in that: the positioning and locking plate includes an end positioning plate for reference positioning and a main body for enhancing structural strength The end faces of both sides of the end positioning plate are the lateral reference planes, and a transitional connection is made between the main plate and the end positioning plate through a transition plate with a trapezoidal cross section.