CN111843257A - Inner rounding device of heat exchanger header and welding method of heat exchanger header - Google Patents

Abstract

The invention discloses an inner side circle supporting device of a heat exchanger header and a welding method of the heat exchanger header, wherein the device comprises two arc-shaped plates, one ends of the two arc-shaped plates are hinged, and the other ends of the two arc-shaped plates are supported through a supporting rod; bracing piece one end is articulated with an arc, and the other end and another arc butt make the butt department dislocation between bracing piece and the arc again after accomplishing head spot welding or welding completely, and then make two arcs break away from with heat exchanger header inner wall, take out in the heat exchanger header.

Description

Inner rounding device of heat exchanger header and welding method of heat exchanger header

technical field

The invention relates to a processing auxiliary tool for a heat exchanger header in the field of nuclear power and a welding method for the heat exchanger header.

Background technique

Heat exchangers are widely used in chemical, petroleum, nuclear energy and other industrial fields. It is a pressure vessel that converts heat into power through heat transfer. It has a wide variety of heat exchange structures. For example, a plate heat exchanger is a common heat exchanger, and its heat exchange part consists of four sets of headers and heat exchange tubes. Spherical head welded composition.

In the field of nuclear power, a heat exchanger header with an outer diameter of 273mm, a wall thickness of 5mm and a length of 2200mm is required. Due to its size and construction limitations, all welding grooves are outside grooves. The manufacturing process is as follows: the upper tube sheet and the C-shaped cylinder are welded into a whole cylinder through two welding seams, and then butt-welded with the head to form an integral header. In the manufacturing standard, there is only a strict requirement of 1.5mm for the misalignment of 5mm plate welds. In the design requirements, the C-shaped cylinder must be gas-cut with a thin-walled stainless steel seamless steel pipe of 273×5mm.

According to the analysis of the above process requirements, the following problems will exist when the tube sheet and the C-shaped cylinder are butt welded: 1. There is internal stress during the cold drawing process of the seamless stainless steel pipe, and it will shrink inward after cutting. In order to ensure the butt joint with the tube sheet When the wrong side is aligned, it is necessary to adjust the wrong side by cold work such as crowbar and top wire support. This method of applying external force locally will affect the roundness of the C-shaped cylinder; 2. Due to the high linear expansion coefficient of stainless steel and high resistance It has the characteristics of high thermal conductivity and low thermal conductivity, and the welding deformation is large. The C-shaped cylinder is a thin-walled cylinder, and there is a tendency to shrink and deform to the groove side of the tube sheet during welding, which causes the C-shaped cylinder to become elliptical after welding.

The above problems will affect the roundness of the tube sheet and the C-shaped cylinder after welding, resulting in the unqualified amount of misalignment with the head. Usually, in order to ensure the processing quality of the heat exchanger, it is necessary to install a rounding tool on the inner side of the cylinder closer to the welding seam before welding, so as to control the roundness of the cylinder. During the welding process, the shrinkage and deformation of the welding seam will be supported. The round tooling resists, can control the roundness, and removes it after welding the butt parts with it.

However, for the slender heat exchanger header with an outer diameter of 273mm, a thickness of 5mm and a length of 2200mm, due to its small wall thickness, the shrinkage stress is large, that is, the deformation is large, and the inner wall is pressed for the rounding tooling. To a greater extent, it is difficult to remove the tooling directly after welding, and it needs to be removed by destructive methods such as cutting. However, due to the long length of the heat exchanger header and the small inner diameter, the tooling is installed at the head end of the sealing C-shaped cylinder, and personnel will not be able to access and remove the head after the head is connected, so it is difficult to achieve the inner support according to the above method. round.

Due to the above reasons, the inventors have conducted in-depth research on the existing auxiliary tool for welding heat exchanger headers and the welding method of heat exchanger headers, in order to design a heat exchanger header that can solve the above problems. The inner rounding device and the welding method of the heat exchanger header.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned problems, the inventors have carried out keen research and designed a device for rounding the inner side of a heat exchanger header and a welding method for the heat exchanger header. The device includes two arc-shaped plates for supporting the One end of the two arc-shaped plates is hinged, and the other end is supported by a support rod; one end of the support rod is hinged with one arc-shaped plate, and the other end is abutted with another arc-shaped plate. After the spot welding or complete welding is completed, the abutment between the support rod and the arc-shaped plate is dislocated, so that the two arc-shaped plates are separated from the inner wall of the heat exchanger header and taken out from the heat exchanger header, thereby The present invention has been completed.

Specifically, the purpose of the present invention is to provide a device for rounding the inner side of a heat exchanger header, the device includes an upper arc-shaped plate 11 and a lower arc-shaped plate 12 that are detachably connected to the connecting ends, and the upper arc-shaped plate 11 And the lower arc-shaped plate 12 is used to abut the inner wall of the heat exchanger header to support the heat exchanger header 2 from the inside.

Wherein, the heat exchanger header 2 includes a tube sheet 21, a C-shaped cylinder 22 with a C-shaped cross-section, and a spherical head 23;

The length of the tube sheet 21 is consistent with the length of the C-shaped cylinder 22, and the two sides of the tube sheet are welded and fixed on both sides of the gap of the C-shaped cylinder 22, and the tube sheet blocks the gap of the C-shaped cylinder to obtain a tube with both ends open. The spherical head 23 is sealed and welded at one of the openings.

Wherein, a support rod 3 is arranged between the upper arc-shaped plate 11 and the lower arc-shaped plate 12 , the support rod 3 is retractable, and the C-shaped cylinder 22 is expanded and supported outward by the support rod 3, so that the The inner diameter of the C-shaped cylinder 22 is gradually increased until the welding requirements are met.

The present invention also provides a heat exchanger header welding method, in which,

Before welding the tube sheet, the C-shaped cylinder shrunk inwardly is stretched by screwing the ejector rod 33, so that the inner diameter of the C-shaped cylinder is restored to the design size before cutting;

Preferably, after the spherical head is fixed by spot welding, the inner rounding device is pulled out from the heat exchanger header by pulling the rope 4 .

The method includes the following steps:

Step 1, take the material and cut the material, that is, cut a cylinder with a length of 2200mm from a cold-drawn steel pipe with an outer diameter of 273mm and a thickness of 5mm, and cut it to form a C-shaped cylinder;

Step 2, install the inner rounding device 1 into the C-shaped cylinder;

Step 3, by screwing the ejector rod 33 to open the C-shaped cylinder that shrinks inwardly, so that the inner diameter of the C-shaped cylinder is restored to 263mm;

Step 4, adjust the relative position of the tube sheet and the C-shaped cylinder, and weld the tube sheet;

Step 5: Check the roundness and welding misalignment after welding the tube sheet on the C-shaped cylinder. When the roundness and misalignment meet the requirements, the welded cylinder is butted with the spherical head, and the spherical head is fixed by spot welding. head;

Step 6, by pulling the rope 4, the support rod 3 on the inner rounding device is rotated around the pin shaft 2, so that the support between the upper arc plate 11 and the lower arc plate 12 is lost, and then the inner rounding device 1 With the rope 4 pulled out from the heat exchanger header 2;

Step 7, Solder the spherical head.

The beneficial effects of the present invention include:

(1) According to the inner rounding device of the heat exchanger header and the inner rounding device in the heat exchanger header welding method provided by the present invention, the structure is simple, the use is light, and the cost is low;

(2) The upper and lower arc-shaped plates in the heat exchanger header inner side rounding device and the heat exchanger header welding method provided by the present invention are integrally fitted with the cylinder body, and the rounding effect is remarkable;

(3) In the heat exchanger header inner rounding device and the heat exchanger header welding method provided by the present invention, the support and removal of the unreachable area can be realized, and the removal will not be damaged and can be reused.

Description of drawings

Fig. 1 shows a schematic structural diagram of a heat exchanger header and an inner rounding device inside thereof according to a preferred embodiment of the present invention;

FIG. 2 shows a schematic structural diagram of an inner circle-stretching device according to a preferred embodiment of the present invention;

Fig. 3 shows a schematic diagram of the structure when the support rod is pulled apart according to a preferred embodiment of the present invention;

FIG. 4 shows a schematic structural diagram of a lower section of a support rod according to a preferred embodiment of the present invention;

Fig. 5 shows the structural schematic diagram of the transmission member at the lower section according to a preferred embodiment of the present invention;

FIG. 6 shows a logic flow diagram of a method for welding a header of a heat exchanger according to a preferred embodiment of the present invention.

Description of reference numbers:

1-Inside rounding device

11-Upper curved plate

111-axis connecting plate

112-pin shaft two

12-Lower arc plate

121-Support block

13-pin one

2 - Heat Exchanger Header

21-tube sheet

22-C barrel

23-ball head

3-Support rod

31-Top connector

32-Screw

33 - ejector

331 - upper paragraph

332-Lower paragraph

333-plane

334-connection slot

335-Sleeve Department

336-shaft part

4- Rope

5- Transmission components

51-Spherical Ball

52-Limit frame

Detailed ways

The present invention will be further described in detail below through the accompanying drawings and embodiments. The features and advantages of the present invention will become more apparent from these descriptions.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. While various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

According to the inner rounding device of the heat exchanger header provided by the present invention, as shown in FIG. 1 and FIG. 2 , the inner rounding device 1 is installed inside the heat exchanger header, and the inner rounding device 1 includes an upper arc shape The plate 11 and the lower arcuate plate 12, the upper arcuate plate 11 and the lower arcuate plate 12 are used to abut the inner wall of the heat exchanger header to support the heat exchanger header from the inside.

The heat exchanger header 2 includes a tube sheet 21 , a C-shaped cylinder 22 with a C-shaped cross section, and a spherical head 23 . The length of the tube sheet 21 is the same as the length of the C-shaped cylinder, and the tube sheet is welded and fixed at the gap of the C-shaped cylinder, and the tube sheet can just block the gap of the C-shaped cylinder; the tube sheet is welded on the C-shaped cylinder. After the notch, a cylindrical structure with two ends open is obtained, and the spherical head is sealed and welded at one of the openings.

Since the C-shaped cylinder 22 will shrink inward under the action of stress after being cut and formed, its inner diameter will generally shrink from a standard circle of 263mm to about 253mm, becoming a special-shaped arc surface; at this time, if the inner support is installed directly into the C-shaped cylinder A circular device, a general circular stretching device with an outer diameter of 263mm is difficult to install directly, and other sizes of circular stretching devices cannot meet the support requirements. The outer end faces are all arc surfaces, of which the outer end face is a standard arc surface, the outer end face is used to abut with the inner wall surface of the heat exchanger header, and the arc radius corresponding to the outer end face is 131.5mm; the upper arc plate 11 and the ends of the lower arc-shaped plate 12 are hinged, that is, the upper arc-shaped plate 11 and the lower arc-shaped plate 12 are connected as a whole through a pin shaft 13, and the pin shaft 13 makes the outline size of the inner rounding device can be adjusted. It can be put into the C-shaped cylinder with a smaller outer diameter, and then gradually expand its outer diameter so as to be in close contact with the inner wall of the heat exchanger header 2 .

The lower arc-shaped plate 12 and the upper arc-shaped plate 11 have the same structural dimensions, and the arc radius corresponding to the outer end surface thereof is also 131.5 mm. When the inner wall surface of the heat exchanger header is completely in close contact, the inner diameter of the heat exchanger header can just reach 263 mm.

Preferably, the arc angles corresponding to the upper arc-shaped plate 11 and the lower arc-shaped plate 12 are both 130°˜160°, preferably 145°. The upper arc-shaped plate 11 and the lower arc-shaped plate 12 partially overlap at the hinge joint, so that the arc angle obtained after the upper arc-shaped plate 11 and the lower arc-shaped plate 12 are hinged is 260 degrees. By setting the specific angles of the above-mentioned upper arc-shaped plate 11 and the lower arc-shaped plate 12, the arc angle obtained after hinged connection is greater than 180 degrees, ensuring that the heat exchanger header can be supported in the vertical direction, and the hinged connection obtains The angle of the circular arc should not be too large, and it is necessary to ensure that a predetermined gap is reserved between the hinged arc and the tube sheet, so that the inner rounding device will not collide with the tube sheet during the loading and unloading process, and prevent the tube sheet from interfering with the device. Loading and unloading also prevents scratching the tube sheet.

In a preferred embodiment, a support rod 3 is further arranged between the upper arc-shaped plate 11 and the lower arc-shaped plate 12 , preferably, the support rod is vertically arranged, and the center of the support rod 3 is changed. The axis of the C-shaped cylinder of the heat exchanger header can make the support rod 3 bear the shrinkage stress of the heat exchanger header and play a main supporting role.

Preferably, the support rod 3 is retractable, so that when the C-shaped cylinder 22 and the tube sheet 21 are not welded, the inner rounding device can be placed in the C-shaped cylinder 22, and the support rod 3 is controlled gradually. By elongation, the outer diameter of the inner rounding device is gradually increased, and then the C-shaped cylinder 22 is expanded outwardly, so that the inner diameter is gradually increased until it reaches 263mm which meets the welding requirements.

Specifically, as shown in FIG. 2 , the support rod 3 includes a top connecting head 31 , a screw 32 and a top rod 33 in sequence from top to bottom, wherein the top connecting head 31 and the screw 32 are an integral structure, and the two can pass through Welding, etc. to fix the connection.

As shown in FIG. 2 and FIG. 4 , the ejector rod 33 includes an upper section 331 and a lower section 332 , wherein the outside of the upper section 331 is cut into a plurality of planes, which can be 4 planes or 6 planes, that is, the outer section of the upper section 331 is provided There is a screwing platform, so that the ejector rod 33 can be rotated by a wrench and other tools, and a threaded cavity matched with the screw rod 32 is opened inside the upper section, and the ejector rod 33 and the screw rod can be controlled by screwing the ejector rod 33 The relative movement between 32 in the vertical direction, that is, the length dimension of the support rod 3 can be adjusted by screwing the top rod 33 .

In a preferred embodiment, the inner rounding device is placed before the tube sheet 21 is welded, a wrench can be inserted from the position where the tube sheet is to be installed to screw the ejector rod 33, and then the height of the support rod 3 can be adjusted. After the board is installed and welded, the spherical head 23 is continued to be installed and welded. At this time, there is no room for operation to screw the ejector rod 33 . Therefore, the support rod 3 cannot be disassembled by screwing the top rod 33. Therefore, when disassembling the support rod 3, the support rod 3 is pulled by providing a lateral force, so that the support rod is separated from the lower arc plate 12. touch.

Preferably, as shown in FIG. 4 , the bottom surface of the lower section 332 of the ejector rod is a spherical surface, and the lower part of the spherical surface is a plane 333 formed by horizontal cutting.

Preferably, as shown in FIG. 2 , a shaft connecting plate 111 is provided on the upper arc-shaped plate 11 , and the shaft connecting plate 111 is hinged with the top connecting head 31 , that is, the shaft connecting plate 111 and the top connecting head 31 are hinged. The second pin 112 is connected between them, so that the support rod 3 can rotate around the second pin 112. When the support rod 3 is vertically installed directly under the upper arc plate 11, the second pin 112 can The deformation stress in the heat exchanger header is transferred to the support rods 3 .

Preferably, as shown in FIG. 2 , a support block 121 is provided on the lower arc-shaped plate 12 , and the top surface of the support block 121 is a smooth plane for abutting with the plane 333 on the lower section 332 .

The top end of the support rod 3 is hinged with the shaft connecting plate 111 of the upper arc-shaped plate 11 through the top connecting head 31, and the bottom end of the support rod 3 is in contact with the support block 121 of the lower arc-shaped plate 12 through the plane 333, so as to So that the vertically arranged support rod 3 can bear the force in the vertical direction, support the upper arc-shaped plate 11 and the lower arc-shaped plate 12, and prevent the stress deformation of the heat exchanger header. When the inner rounding device needs to be disassembled, By exerting a lateral force on the support rod 3, the plane 333 can be disengaged from the support block 121 of the lower arc-shaped plate 12, as shown in FIG. 3, and then the upper and lower arc-shaped plates 11 and 12 It is bent inward around the pin one 13 due to the loss of support.

Preferably, the bottom of the lower section 332 of the top rod is set as a spherical shape as a whole, so that when the support rod 3 rotates around the second pin shaft 112, the friction between the plane 333 and the support block 121 is smaller, that is, the friction between the plane 333 and the support block 121 is reduced. The contact area between the support rod 3 and the support block 121 can also prevent the support rod 3 from being unable to rotate due to being stuck.

When the area size of the plane 333 is large, the stability of the support rod 3 can be improved, but it will lead to increased difficulty in disassembling the inner rounding device, or even impossible to disassemble. When the area size is small, it can be convenient for the inner side. The disassembly of the rounding device will also lead to a decrease in the stability of the support rod 3 . The inventors found that when the plane area is 220-240 mm ² , the above requirements can be met, and more preferably, when the plane is a circle with a diameter of 17 mm, the best effect is achieved.

Preferably, since the length of the heat exchanger header is more than two meters and the inner diameter is less than 30 cm, it is difficult for the operator to enter the heat exchanger header after welding is completed, even if only the support rod 3 needs to be moved. The dismantling of the inner rounding device is difficult to achieve in the actual operation process. For this reason, a concave connecting groove 334 is provided on the lower section 332 of the ejector rod 33, and a rope 4 is wound and fixed in the connecting groove 334. , the other end of the rope 4 extends to the outside of the heat exchanger header along the axial length direction of the heat exchanger header. In the initial installation of the inner rounding device, one end of the rope 4 is fixed on the connecting groove 33, and the other end is fixed on the outside of the heat exchanger header. Preferably, a fixing clamp is provided outside the heat exchanger header for clamping the end of the fixing rope 4 located outside the heat exchanger header, so that when the inner rounding device needs to be disassembled, the rope 4 can be pulled directly. accomplish. More preferably, the rope 4 is a steel wire rope, and an inverted chain is connected at one end of the rope 4 outside the header of the heat exchanger, so that sufficient tension is provided by the inverted chain to pull the inner rounding device.

In a preferred embodiment, in order to ensure that the inner rounding device can be pulled out of the heat exchanger header smoothly, it must be ensured that the plane 333 of the support rod 3 can be on the support block 121 under the action of external force/rope tension However, in actual work, due to the small area of the plane and the huge force on the support rod 3, the pressure is extremely large, and the upper surface of the support block 121 is easily dented inward due to the compression, and the support The flat surface 333 of the rod 3 falls into the depression, which increases the difficulty for the subsequent pulling of the support rod 3; further, after installing the inner rounding device, it is necessary to increase the length of the support block 121 by rotating the top rod 33, so that the The inner diameter size of the C-shaped cylinder is increased to the expected size. During this process, the plane 333 rotates with the ejector rod 33, which increases the friction between the plane 333 and the support block 121, further aggravating the support block 121 due to being pressed. The severity of the inward depression also makes it more difficult to screw the ejector pin 33 due to this friction.

In the present invention, the lower section 332 of the ejector rod 33 is set into two parts, as shown in FIG. 5 , that is, the lower section 332 includes a sleeve part 335 connected with the upper part 331 and a shaft whose top end is embedded in the sleeve part 335 part 336 , the connecting groove 334 is located on the rotating shaft part 336 .

Inside the sleeve portion 335 , a transmission member 5 is provided between the inner top surface of the sleeve portion 335 and the top surface of the rotating shaft portion 336 , and the transmission member 5 includes spherical balls 51 . Preferably, a limiting frame 52 is provided outside the spherical balls to limit the spherical balls 51 so that they can only roll between the inner top surface of the sleeve portion 335 and the top surface of the rotating shaft portion 336; by setting the transmission member 5, so that when the upper section 331 is screwed, the connecting groove 334 and the flat surface 333 on the shaft part 336 do not need to rotate synchronously with the upper section 331, thereby reducing the possibility and degree of inward concave on the support block 121, thereby ensuring The reliability of the operation of pulling the support rod 3 away.

Preferably, there is at least one spherical ball 51. When there are multiple spherical balls 51, each spherical ball 51 is completely consistent with each other, and is evenly distributed in the sleeve portion 335, and each spherical ball 51 is located in the same one In the horizontal plane, under the restriction of the limiting frame 52, each spherical ball 51 maintains a predetermined gap and does not contact each other.

In a preferred embodiment, a scale is provided on the support rod 3, and the scale is located near the screw 32 and the ejector rod 33 to display the total height of the support rod 3, or to display the inner circle The total height of the device, so the inner diameter of the C-shaped cylinder 22 can be known in real time through this scale, which is convenient for the user to determine the degree of screwing of the ejector rod 33, quickly and accurately spread the C-shaped cylinder 22 to a predetermined size, and maintain at the predetermined size.

The present invention also provides a heat exchanger header welding method, as shown in FIG. 6 , the method includes the following steps:

Step 1, take the material and cut the material, that is, cut a cylinder with a length of 2200mm from a cold-drawn steel pipe with an outer diameter of 273mm and a thickness of 5mm, and cut it to form a C-shaped cylinder.

Step 2, install the inner rounding device into the C-shaped cylinder. The number of the inner rounding device is one or more, and at least one of the inner rounding device is set near the spherical head. , when a plurality of inner rounding devices are provided, they are arranged at a predetermined distance from each other. Preferably, the inner rounding device is the inner rounding device described above.

Step 3, by screwing the ejector rod 33 to open the C-shaped cylinder contracted inwardly, so that the inner diameter of the C-shaped cylinder is restored to 263 mm.

Step 4, adjust the relative position of the tube sheet and the C-shaped cylinder, and weld the tube sheet.

Step 5: Check the roundness and welding misalignment after welding the tube sheet on the C-shaped cylinder. When the roundness and misalignment meet the requirements, the welded cylinder is butted with the spherical head, and the spherical head is fixed by spot welding. header.

Step 6: The support rod 3 on the inner rounding device is urged to rotate around the pin shaft 2 by pulling the rope, and then the support between the upper arc plate 11 and the lower arc plate 12 is lost, and the inner rounding device is followed by the rope. Pull out of the heat exchanger header.

Step 7. Weld the spherical head tightly to the barrel.

Preferably, in step 2, the inner rounding device 1 is installed into the C-shaped cylinder, so that both the upper arc-shaped plate 11 and the lower arc-shaped plate 12 abut on the inner wall of the C-shaped cylinder, and the support rod 3 is adjusted to In the vertical state, the lower part of the support rod 3 abuts on the top surface of the support block 121 . Among them, in the process of installing the support rod 3, the support rod is first contracted and the bottom plane 333 is abutted on the support block 121, until the upper arc-shaped plate 11 and the lower arc-shaped plate 12 are in contact with the inner wall of the C-shaped cylinder. After connecting, screw the top rod 33 to make the length of the support rod 3 gradually increase. During this process, the contact between the plane 333 and the support block 121 is getting tighter and tighter, and continue to observe the contact position between the two, and properly Correct the angle/direction of the support rod 3 so that the support block 121 and the plane 333 are completely fitted.

Preferably, in step 3, measure the diameter of the inner wall of the C-shaped cylinder before screwing the ejector rod 33, and record it, and measure the inner wall diameter of the C-shaped cylinder after every 3 to 5 turns of screwing. When the inner wall diameter of the C-shaped cylinder approaches 263mm , measure it once every turn to ensure that the diameter of the inner wall of the C-shaped cylinder is just expanded to 263mm.

More preferably, when a scale is provided on the support rod 3, the current C-shaped cylinder inner wall diameter can be known by reading the corresponding value of the scale in real time, when the C-shaped cylinder inner wall diameter is close to 263mm, such as When it is 262mm, the diameter of the inner wall of the C-shaped cylinder should be measured again every one twist, so as to ensure that the inner wall of the C-shaped cylinder is just expanded to 263mm.

Preferably, in step 4, the relative position of the tube sheet and the C-shaped cylinder should specifically meet the index requirements that the displacement of the inner side of the butt weld between the tube sheet and the C-shaped cylinder is less than 1.5 mm, and the diameter tolerance of the C-shaped cylinder is 263±2 mm. Then proceed to the welding operation.

Preferably, in step 5, when the roundness is less than 3 mm and the misalignment is less than 1.5 mm, the roundness and misalignment meet the requirements, and the cylinder is butted with the spherical head.

Preferably, in step 6, in the process of pulling the rope 4, it is initially known through the reverse chain (chain hoist) that the jack provides a pulling force, so that the plane 333 of the support rod 3 is out of contact with the support block 121, and the support rod 3 is pulled. Then, manually pull the rope 4.

Experimental example:

A 273×5mm thin-walled stainless steel seamless steel pipe is selected, and a C-shaped cylinder with a length of 2200mm is formed by gas cutting. Among them, the design width of the gap on the C-shaped cylinder is 180mm, the actual measurement is 170~175mm, and the inner diameter of the C-shaped cylinder is 253~175mm. 258mm,

Install the inner rounding device in the C-shaped cylinder near the spherical head, as shown in Figure 1 and Figure 3, the upper arc plate and the lower arc plate are hinged, and the upper arc plate and the lower arc plate are abutting On the inner wall of the C-shaped cylinder, a support rod is arranged between the upper arc-shaped plate and the lower arc-shaped plate. The length of the support rod is adjusted by rotating the top rod on the support rod, and the inner diameter of the C-shaped cylinder is gradually increased. The support is restored to 263mm;

Adjust the relative position of the tube sheet and the C-shaped cylinder, and weld the tube sheet,

After the welding is completed, check that the roundness of the welded tube sheet on the C-shaped cylinder is 2mm, and the welding misalignment is 1mm; when the roundness of the tube sheet is less than 3mm and the misalignment is less than 1.5mm, it is considered that the tube sheet is welded. The quality meets the requirements, so the welding quality of the above-mentioned tube sheets meets the requirements, and then the spherical head is butted with the C-shaped cylinder behind the welded tube sheet, and the misalignment of the butt is controlled below 1.5mm. head;

By pulling the rope backwards, the support rod 3 on the inner rounding device is driven to rotate around the pin shaft 2, and then the support between the upper arc plate 11 and the lower arc plate 12 is lost, and the inner rounding device is connected to the heat exchanger. The header is out of contact, and the inner rounding device is pulled out from the heat exchanger header along with the rope;

Finally, the spherical head is welded, and the welding quality of the head can reach less than 1.5mm of misalignment inside the weld, and the back side is well formed after welding, which meets the requirements of radiographic inspection.

It can be seen from the above experimental examples that a heat exchanger header with good welding quality can be obtained by the heat exchanger header welding method provided by the present invention.

The present invention has been described above with reference to the preferred embodiments, but these embodiments are merely exemplary and serve only for illustrative purposes. On this basis, various substitutions and improvements can be made to the present invention, which all fall within the protection scope of the present invention.

Claims (10)

1. A device for rounding the inner side of a header of a heat exchanger, characterized in that the device comprises an upper arc-shaped plate (11) and a lower arc-shaped plate (12) which are detachably connected at the connected ends, A support rod (3) with adjustable length is arranged between the shaped plate (11) and the lower arc-shaped plate (12), and the upper arc-shaped plate (11) and the lower arc-shaped plate (12) are used for abutting the heat exchanger coupling. The inner wall of the box supports the heat exchanger header (2) from the inside. 2. The inner side rounding device of the heat exchanger header according to claim 1, is characterized in that, The heat exchanger header (2) includes a tube sheet (21), a C-shaped cylinder (22) with a C-shaped cross section, and a spherical head (23); The length of the tube sheet (21) is the same as the length of the C-shaped cylinder (22), and both sides of the tube sheet are welded and fixed on both sides of the gap of the C-shaped cylinder (22), and the tube sheet blocks the gap of the C-shaped cylinder, A cylindrical structure with openings at both ends is obtained, and the spherical head (23) is sealed and welded at one of the openings. 3. The device for rounding the inner side of the heat exchanger header according to claim 2, characterized in that, The outer end surfaces of the upper arc-shaped plate (11) and the lower arc-shaped plate (12) abutting against the inner wall of the heat exchanger header are standard circular arc surfaces, and the diameter of the circular arc surface is the same as that in the heat exchanger header. The inner diameters of the C-shaped cylinders (22) are the same. 4. The device for rounding the inner side of the heat exchanger header according to claim 2, characterized in that, The support rod (3) is retractable, and the C-shaped cylinder (22) is extended and extended outward through the support rod (3), so that the inner diameter of the C-shaped cylinder (22) is gradually increased until the welding requirements are met . 5. The device for rounding the inner side of the heat exchanger header according to claim 1, characterized in that, The support rod (3) includes a top connecting head (31), a screw rod (32) and an ejector rod (33) in sequence from top to bottom; The ejector rod (33) includes an upper section (331) and a lower section (332), wherein a screwing platform is provided outside the upper section (331) to facilitate the rotation of the ejector rod (33), A threaded cavity matched with the screw rod (32) is provided inside the upper section (331), so that the length of the support rod (3) can be adjusted by screwing the top rod (33). 6. The device for rounding the inner side of the heat exchanger header according to claim 5, characterized in that, The bottom surface of the lower section (332) of the ejector rod is a spherical surface, and the lower part thereof is a plane (333) formed by horizontal cutting; Preferably, a support block (121) is provided on the lower arc-shaped plate (12), and the top surface of the support block (121) is a smooth plane for abutting against the plane (333) on the lower section (332). catch. 7. The device for rounding the inner side of the heat exchanger header according to claim 5, characterized in that, A shaft connecting plate (111) is arranged on the upper arc-shaped plate (11), and the shaft connecting plate (111) is hinged with the top connecting head (31). 8. The device for rounding the inner side of the heat exchanger header according to claim 5, characterized in that A concave connecting groove (334) is provided on the lower section (332) of the top rod (33), a rope (4) is wound and fixed in the connecting groove (334), and the other end of the rope 4 is along the heat exchange The axial length direction of the heat exchanger header extends to the outside of the heat exchanger header. 9. A heat exchanger header welding method, characterized in that, in the method: Before welding the tube sheet, screw the ejector rod (33) to open the C-shaped cylinder shrinking inwardly, so that the inner diameter of the C-shaped cylinder is restored to the design size before cutting; After the spherical head is fixed by spot welding, the support rod 3 of the inner rounding device is rotated around the second pin shaft by pulling the rope (4), and the inner rounding device of the heat exchanger header changes from the tightened state to the non-stretched state. , and pulled out from the heat exchanger header by rope (4). 10. The heat exchanger header welding method according to claim 9, wherein the method comprises the steps of: Step 1, take the material and cut the material to obtain a C-shaped cylinder, Step 2, install the inner rounding device (1) into the C-shaped cylinder; Step 3, by screwing the ejector rod (33) to open the C-shaped cylinder shrinking inwardly, so that the inner diameter of the C-shaped cylinder is restored to 263mm; Step 4, adjust the relative position of the tube sheet and the C-shaped cylinder, and weld the tube sheet; Step 5: Check the roundness and welding misalignment after welding the tube sheet on the C-shaped cylinder. When the roundness and misalignment meet the requirements, the welded cylinder is butted with the spherical head, and the spherical head is fixed by spot welding. head; Step 6, by pulling the rope (4), the support rod 3 on the inner rounding device is rotated around the pin shaft 2, so that the support between the upper arc plate (11) and the lower arc plate (12) is lost, and then the The inner rounding device (1) is pulled out from the heat exchanger header (2) along with the rope (4); Step 7. Weld the spherical head tightly to the barrel.

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