Connecting structure of header in high-pressure heater

Abstract

The utility model relates to a connecting structure of a header in a high-pressure heater, which comprises a sealed shell and the header arranged in the shell, two ends of the header are arranged on two opposite side walls of the shell, coaxial through holes are arranged at joints of the two ends of the shell opposite to the header, and the outer side surface of one end of the header is welded in the through holes on the side walls of the shell. A telescopic sleeve is arranged in the other opposite through hole of the shell, the other end of the collecting box extends into and is connected into the telescopic sleeve, and when the collecting box stretches out and draws back in the axial direction under stress, the telescopic sleeve is driven to move in the axial direction, and the stress of the collecting box is released. The telescopic sleeve comprises a first pressing ring welded to the through hole of the shell and a second pressing ring fixed to the outer end of the collecting box, the first pressing ring and the second pressing ring are connected through an expansion joint, the collecting box can slide and move in the first pressing ring to release stress, the collecting box pushes the second pressing ring to move, and the expansion joint is unfolded to deform. The welding stress at the welding position of the header is greatly reduced, and cracks at the welding position can be effectively prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of thermal power generation equipment, in particular to a connection structure of a header in a high-pressure heater. Background Art

[0002] At present, in the newly built supercritical unit engineering thermal power generation projects, the connection method between the serpentine tube high-pressure heater header connecting pipe and the shell is usually a single-sided welding connection structure of the connecting pipe and the shell insert fillet weld. The shell material is relatively thick and is made of low-alloy high-strength steel. It has a strong tendency to be hardened by welding, and the residual stress after welding is large. Although the later stress relief heat treatment can eliminate part of the welding stress, the overall stress condition of the single-sided welding connection joint of this fillet weld structure is poor, and the residual stress after welding is large. Especially under the condition of the deadweight of the header in the horizontal container design structure, the stress of the welding joint at the connection between the header connecting pipe and the shell will be further increased. In addition, the load stress of the header connecting pipe and the external pipeline, and the temperature difference stress inside and outside the header connecting pipe, the equipment is easily heated and expanded by high temperature and high pressure after operation, and crack defects will appear in the heat-affected zone of the fillet weld of the connection joint between the header connecting pipe and the shell, affecting the safety of the equipment in the later use, and the welding quality cannot be guaranteed. After the crack defect occurs, the entire generator set is forced to shut down, affecting the power generation capacity. After the welding of the header connecting pipe and the shell is completed, the constraint degree is high, and there is a large welding residual stress, and the stress relief heat treatment cannot be effectively improved. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide a connection structure of a header in a high-pressure heater to solve the problem of cracks in a header joint.

[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0005] A connection structure for a header in a high-pressure heater comprises a sealed shell and a header arranged in the shell, wherein the two ends of the header are arranged on opposite side walls of the shell, and coaxial through holes are provided at the connection points of the two ends of the shell relative to the header. The outer side surface of one end of the header is welded in the through hole of the side wall of the shell, and a telescopic sleeve is provided in the other through hole of the shell. The other end of the header extends into and is connected to the telescopic sleeve. When the header is subjected to stress and expands axially, the telescopic sleeve is driven to move axially to release the stress of the header.

[0006] As a preferred embodiment, the telescopic sleeve includes a first compression ring and a second compression ring which are coaxially and spaced apart from each other. The outer circumferential surface of the first compression ring is fixed in the through hole of the shell, and the second compression ring is spaced apart and arranged on one side close to the outer end of the first compression ring. The second compression ring and the first compression ring are connected by an annular expansion joint, and the expansion joint can move axially when subjected to force. The inner circumference of the second compression ring is fixedly connected to the collecting box, and the outer circumference of the collecting box can be axially movably embedded in the interior of the first compression ring.

[0007] As a preferred embodiment, the cross-section of the expansion joint is in the shape of "Ω", and the expansion joint includes an arc top with an opening at the lower end, and the bottom sides of the arc top are respectively connected with symmetrical first arc sides and second arc sides, the interiors of the arc top, the first arc side and the second arc side form an inner cavity, the bottom opening of the inner cavity faces the outer circumferential surface where the collecting box is located, the outer side surface of the arc of the first arc side away from the inner cavity is welded to the outer end side surface of the first pressure ring, the outer side surface of the arc of the second arc side away from the inner cavity is welded to the corresponding side surface of the second pressure ring, and the arc top is exposed outside the outer circumferential surface of the first pressure ring and the second pressure ring.

[0008] As a preferred implementation scheme, the expansion joint is made of stainless steel.

[0009] As a preferred embodiment, the outer sides of the first pressure ring and the second pressure ring are connected by circumferentially distributed connecting parts, which include bolts and connecting plates. The connecting plates are arranged on the outer circumference of the second pressure ring along the radial circumference of the second pressure ring, the bolts are arranged parallel to the axial direction of the collecting box, and one end of the bolt is fixed on the step surface of the first pressure ring, and the other end of the bolt passes through the connecting plate and is tightened with a nut.

[0010] As a preferred embodiment, the shell and the header are both axially horizontal cylindrical shells, and the header is arranged to penetrate the middle of the shell along the horizontal radial direction of the shell.

[0011] As a preferred embodiment, a first connecting pipe and a second connecting pipe are respectively provided at both ends of the header, the first connecting pipe is welded in the through hole of the shell, and the second connecting pipe extends into and is connected to the telescopic sleeve.

[0012] As a preferred embodiment, a gap is left between the inner circumferential surface of the first pressure ring and the outer circumferential surface of the second connecting pipe.

[0013] The beneficial effects of the utility model are as follows: one end of the header is welded to the through hole of the side wall of the shell, and the other end of the header is axially displaced on the through hole of the side wall corresponding to the cavity through a telescopic sleeve. When the overall uneven force on the header causes axial expansion and contraction, the displacement is realized in the telescopic sleeve, thereby reducing the welding stress between the first connecting pipe of the header and the shell. The telescopic sleeve includes a first pressure ring welded to the through hole of the shell, and a second pressure ring fixed to the outer end of the header. The first pressure ring and the second pressure ring are connected by an "Ω"-shaped stainless steel expansion joint. The header can slide and displace in the first pressure ring to release stress. The header pushes the second pressure ring to move, and the expansion joint stretches and deforms, so that the header is always sealed and covered, which greatly reduces the welding stress between the first connecting pipe of the header and the shell, and can effectively prevent the occurrence of cracks at the welding point. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The specific implementation of the utility model is further described in detail below with reference to the accompanying drawings, wherein:

[0015] Figure 1 It is a cross-sectional schematic diagram of the utility model;

[0016] Figure 2 It is a side schematic diagram of the utility model;

[0017] Figure 3 It is a front schematic diagram of the utility model;

[0018] Figure 4 for Figure 1 A partial enlarged view of

[0019] Figure 1~Figure 4 Explanation of the reference numerals in the accompanying drawings: 1. collecting box; 2. first connecting pipe; 3. second connecting pipe; 4. shell; 5. first pressure ring; 6. second pressure ring; 7. expansion joint; 8. connecting piece; 71. inner cavity; 72. first arc edge; 73. second arc edge; 74. arc top; 81. bolt; 82. connecting plate. DETAILED DESCRIPTION

[0020] The specific implementation scheme of the utility model is described in detail below in conjunction with the accompanying drawings.

[0021] like Figure 1~Figure 4 The connection structure of the header in the high-pressure heater shown includes a sealed shell 4 and a header 1 arranged in the shell 4, the two ends of the header 1 are arranged on the opposite side walls of the shell 4, and the shell 4 is provided with coaxial through holes at the connection between the two ends of the header 1. The outer side surface of one end of the header 1 is welded in the side wall through hole of the shell 4, and a telescopic sleeve is arranged in the other through hole of the shell 4. The other end of the header 1 extends into the telescopic sleeve and is connected to the telescopic sleeve. When the header 1 is subjected to stress and expands axially, the telescopic sleeve is driven to move axially, thereby releasing the stress of the welding between the first connecting pipe 2 of the header 1 and the shell 4.

[0022] Specifically, due to the large residual stress after welding the first connecting pipe 2 of the header 1 and the shell 4, coupled with the load gravity of the externally connected pipeline, the deadweight of the tube bundle connected to the header, and the expansion caused by the temperature difference between the inside and outside during the temperature conduction process, the overall stress at the welding joint between the first connecting pipe 2 of the header 1 and the shell 4 is large, and cracks are prone to appear at the welding point at one end of the first connecting pipe 2 of the header 1 and the shell 4. Therefore, a connecting component that allows the header 1 to expand and contract axially is provided at the other end of the header 1, so that the deformation caused by the internal stress at the welding point of the first connecting pipe 2 of the header 1 and the shell 4 can be released, the internal stress of the first connecting pipe 2 of the header 1 and the shell 4 can be reduced, and the welding point of the first connecting pipe 2 of the header 1 and the shell 4 can be stably connected.

[0023] like Figure 1The telescopic sleeve includes a first pressure ring 5 and a second pressure ring 6 which are coaxially and spaced apart from each other. The outer circumference of the first pressure ring 5 is fixed in the through hole of the shell 4. The second pressure ring 6 is spaced apart and is arranged on one side close to the outer end of the first pressure ring 5. The second pressure ring 6 and the first pressure ring 5 are connected by an annular expansion joint 7. The expansion joint 7 can move axially when subjected to force. The inner circumference of the second pressure ring 6 is fixedly connected to the header 1, and the outer circumference of the header 1 can be axially movably embedded in the first pressure ring 5. The end of the header 1 away from the welding is axially slidably embedded in the first pressure ring 5. The first pressure ring 5 not only provides support for the header 1, but also enables the header 1 to slide axially to release stress. The second pressure ring 6 is welded and sealed to the side of the header 1 close to the outer end. The outer circumferential surface of the first pressure ring 5 is welded and sealed to the through hole of the shell 4. During the axial movement of the header 1, the second pressure ring 6 is pushed to move synchronously. The second pressure ring 6 and the first pressure ring 5 are connected by a deformable expansion joint 7. During the movement of the header 1, the second pressure ring 6 and the first pressure ring 5 can also be guaranteed to be sealed relative to the header 1.

[0024] like Figure 4 The cross section of the expansion joint 7 is in the shape of "Ω", and the expansion joint 7 includes an arc top 74 with an opening at the lower end, and the bottom sides of the arc top 74 are respectively connected with a symmetrical first arc edge 72 and a second arc edge 73, the arc top 74, the first arc edge 72 and the second arc edge 73 are enclosed in an inner cavity 71, and the bottom opening of the inner cavity 71 faces the outer circumferential surface where the header 1 is located, the arc outer side surface of the first arc edge 72 away from the inner cavity 71 is welded to the outer end side surface of the first pressure ring 5, and the second arc edge 73 away from the inner cavity 71 is welded to the outer end side surface of the first pressure ring 5. The outer side of the arc is welded on the side corresponding to the second pressure ring 6, the arc top 74 is exposed outside the outer circumferential surface of the first pressure ring 5 and the second pressure ring 6, the lower edge of the first arc edge 72 and the second arc edge 73 are respectively welded to the inner circumferential wall of the first pressure ring 5 and the second pressure ring 6 to form a sealed connection, the upper and middle parts of the first arc edge 72 and the second arc edge 73 are in contact with the end faces facing the first pressure ring 5 and the second pressure ring 6, and the end faces facing the first pressure ring 5 and the second pressure ring 6 are respectively formed into arc surfaces adapted to the first arc edge 72 and the second arc edge 73. Such a shape of the expansion joint 7 can make the second pressure ring 6 and the first pressure ring 5 close together, and there is still space for expansion and contraction.

[0025] The expansion joint 7 is made of stainless steel. When expanding and contracting with the second pressure ring 6, the expansion joint 7 made of stainless steel has a certain elasticity, and the process of extending and retracting is relatively reliable.

[0026] In addition, the outer sides of the first compression ring 5 and the second compression ring 6 are connected by a circumferentially distributed connector 8, which includes a bolt 81 and a connecting plate 82. The connecting plate 82 is arranged on the outer circumference of the second compression ring 6 along the radial circumference of the second compression ring 6. The bolt 81 is arranged parallel to the axial direction of the header 1, and one end of the bolt 81 is fixed on the step surface of the first compression ring 5. The other end of the bolt 81 slides through the connecting plate 82 and is tightened with a nut. The connector 8 connects the second compression ring 6 with the first compression ring 5 to increase the overall strength. The nut can limit the axial extension range of the header 1 to prevent the extension range of the header 1 from exceeding the expansion range of the expansion joint 7, resulting in the disconnection of the expansion joint 7 from the first compression ring 5 or the second compression ring 6, causing leakage of high-pressure steam in the shell 4.

[0027] The shell 4 and the header 1 are both cylindrical shells with horizontal axial direction, and the header 1 is arranged in the middle of the shell 4 along the horizontal radial direction of the shell 4. During the heat exchange process, the cylindrical contact area is large and it is easy to achieve sealing.

[0028] like Figure 1 The two ends of the header 1 are respectively provided with a first connecting pipe 2 and a second connecting pipe 3, the first connecting pipe 2 is welded in the through hole of the shell 4, and the second connecting pipe 3 is extended into and connected in the telescopic sleeve. The two ends of the header 1 are respectively provided on the shell 4 through the first connecting pipe 2 and the second connecting pipe 3.

[0029] There is a gap between the inner circumference of the first pressure ring 5 and the outer circumference of the second connecting pipe 3 , so that the header 1 can slide in the first pressure ring 5 .

[0030] The working process of the utility model is as follows:

[0031] As shown in Figures 1-4, the first connecting pipe 2 and the second connecting pipe 3 are welded to the two ends of the collecting box 1 respectively. The first connecting pipe 2 connected to one end of the collecting box 1 is welded to the through hole of the shell 4, and the second connecting pipe 3 of the collecting box 1 is not welded to the shell 4. A first pressure ring 5 is welded in the through hole of the shell 4 corresponding to the second connecting pipe 3. One side of the expansion joint 7 is welded to the outer end of the first pressure ring 5, and the other side of the expansion joint 7 is welded to the second pressure ring 6. The inner circumference of the second pressure ring 6 is welded to the outer circumference of the collecting box 1, and the first pressure ring 5 and the second pressure ring 6 are connected by a connecting piece 8.

[0032] The above embodiments are only illustrative of the principles and effects of the invention of the utility model, as well as some embodiments of its application, and are not intended to limit the invention of the utility model. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the invention, and all of these belong to the protection scope of the invention.

Claims

1. A connection structure of a header in a high-pressure heater, characterized in that: The invention comprises a sealed shell (4) and a header (1) arranged in the shell (4), the two ends of the header (1) being arranged on opposite side walls of the shell (4), the shell (4) having coaxial through holes at the connection points of the two ends relative to the header (1), the outer side surface of one end of the header (1) being welded in the through hole of the side wall of the shell (4), the other through hole of the shell (4) being opposite to the other through hole, the other end of the header (1) extending into the telescopic sleeve, when the header (1) is subjected to stress and telescopically telescopes, the telescopic sleeve is driven to move in the axial direction, thereby releasing the stress of the header (1).

2. The connection structure of the header in the high-pressure heater according to claim 1, characterized in that: The telescopic sleeve comprises a first pressure ring (5) and a second pressure ring (6) which are coaxially and spaced apart from each other. The outer circumference of the first pressure ring (5) is fixed in the through hole of the shell (4). The second pressure ring (6) is spaced apart and arranged on one side close to the outer end of the first pressure ring (5). The second pressure ring (6) and the first pressure ring (5) are connected via an annular expansion joint (7). The expansion joint (7) can move axially when subjected to force. The inner circumference of the second pressure ring (6) is fixedly connected to the header (1). The outer circumference of the header (1) is embedded in the first pressure ring (5) so as to be axially movable.

3. The connection structure of the header in the high-pressure heater according to claim 2, characterized in that: The cross section of the expansion joint (7) is in the shape of an "Ω". The expansion joint (7) comprises an arc top (74) with an opening at the lower end, and two sides of the bottom of the arc top (74) are connected to symmetrical first arc sides (72) and second arc sides (73). The interior of the arc top (74), the first arc side (72) and the second arc side (73) form an inner cavity (71). The bottom opening of the inner cavity (71) faces the outer circumferential surface of the header (1). The arc outer side surface of the first arc side (72) away from the inner cavity (71) is welded to the outer end side surface of the first pressure ring (5), and the arc outer side surface of the second arc side (73) away from the inner cavity (71) is welded to the corresponding side surface of the second pressure ring (6). The arc top (74) is exposed outside the outer circumferential surface of the first pressure ring (5) and the second pressure ring (6).

4. The connection structure of the header in the high-pressure heater according to claim 2, characterized in that: The expansion joint (7) is made of stainless steel.

5. The connection structure of the header in the high-pressure heater according to claim 2, characterized in that: The outer sides of the first pressure ring (5) and the second pressure ring (6) are connected via circumferentially distributed connecting pieces (8), the connecting pieces (8) comprising bolts (81) and connecting plates (82), the connecting plates (82) being arranged on the outer circumference of the second pressure ring (6) along the radial circumference of the second pressure ring (6), the bolts (81) being arranged parallel to the axial direction of the header (1), one end of the bolts (81) being fixed on the step surface of the first pressure ring (5), the other end of the bolts (81) passing through the connecting plate (82) and being tightened with a nut.

6. The connection structure of the header in the high-pressure heater according to claim 1, characterized in that: The shell (4) and the header (1) are both axially horizontal cylindrical shells, and the header (1) is arranged in the middle of the shell (4) along the horizontal radial direction of the shell (4).

7. The connection structure of the header in the high-pressure heater according to claim 1, characterized in that: A first connecting pipe (2) and a second connecting pipe (3) are respectively provided at both ends of the header (1); the first connecting pipe (2) is welded in a through hole of the shell (4), and the second connecting pipe (3) extends into and is connected to the telescopic sleeve.

8. The connection structure of the header in the high-pressure heater according to claim 2, characterized in that: A gap is left between the inner circumferential surface of the first pressure ring (5) and the outer circumferential surface of the second connecting pipe (3).

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