Flexible suspension shock absorber for boiler heat exchanger

Abstract

This invention discloses a flexible suspension-type vibration damping device for boiler heat exchangers, comprising a top frame seat (2), a support rod (3), a free suspension assembly, an unrestrained suspension assembly, and a flexible buffer balance pad (4). The support rod is oscillatingly suspended below the top frame seat via the unrestrained suspension assembly. The top of the heat exchange tube (1) is movably suspended on the support rod via the free suspension assembly, allowing the heat exchange tube to move relative to the support rod and the top frame seat. The flexible buffer balance pad is located on both sides of the lower end of the heat exchange tube and at the corresponding striking points of the high-frequency vibrator on the heat exchange tube. This invention can buffer and release the stress of the heat exchange tube through flexible suspension, ensuring efficient heat exchange while also ensuring that the heat exchange tube achieves ash removal, scale removal, and dust removal through high-frequency vibration, thus avoiding frequent fatigue cracking and leakage problems caused by rigid fixing of the heat exchange tube.

Description

Technical Field

[0001] This invention relates to a stress buffer device for heat exchangers, and more particularly to a flexible suspension type vibration damping device for boiler heat exchangers. Background Technology

[0002] To remove accumulated or adhered dirt from the surface of boiler heat exchanger tubes, mechanical rapping is often used to remove the dirt and improve the heat exchange efficiency of the tubes. However, mechanical rapping can lead to new problems. Taking boiler heat exchanger modules as an example, tube rupture and leakage failures occur frequently in the low-temperature zone of the boiler, and the leakage sites are concentrated at the welded parts at the top of the tube bundle, especially in the heat-affected zone or fusion line of the fillet weld of the tubes; the cracks are all brittle cracks, perpendicular to the axis of the tubes, and all cracks originate from the outer wall of the tubes and extend vertically from the outer wall to the inner wall along the thickness direction of the tubes, exhibiting penetrating brittle fracture characteristics. These cracks are unrelated to manufacturing and operating conditions.

[0003] Existing heat exchanger tubes are installed using a rigid suspension welded structure; please refer to the appendix. Figure 1 The rigid suspension welded structure includes a top frame seat 2 and a support rod 3. The top of the heat exchanger tube 1 is welded to the lower end of the support rod 3, and the upper end of the support rod 3 is welded to the top frame seat 2. The heat exchanger tube 1 and its suspension structure are integrally welded into a rigid modular structure. The greater the rigidity of the structure, the greater the restraint. When the lower ends of the heat exchanger tube 1 are subjected to high-frequency vibration, the stress generated will be concentrated on the rigid welded part at the top of the heat exchanger tube 1, causing fatigue cracking of the load-bearing weld, thus leading to frequent tube rupture and leakage problems of the heat exchanger tube 1.

[0004] Currently, the standard procedure for handling pipe bursts and leaks is to locate the leak point, cut off the damaged old pipe, and weld a new pipe. If a pipe burst and leak occurs again, repeating the above process to replace the damaged old pipe does not completely solve the problem at its root. Summary of the Invention

[0005] The purpose of this invention is to provide a flexible suspension shock absorption device for boiler heat exchangers, which can buffer and release the stress of heat exchange tubes through flexible suspension. While ensuring efficient heat exchange, it can also ensure that the heat exchange tubes can achieve the functions of ash removal, scale removal and dust removal by high-frequency vibration, and avoid fatigue cracking and leakage problems caused by rigid fixing of heat exchange tubes.

[0006] This invention is implemented as follows: A flexible suspension vibration damping device for boiler heat exchangers includes a top frame base, a support rod, a free suspension assembly, an unrestrained suspension assembly, and a flexible buffer balance pad. The support rod is swung and suspended below the top frame base via the unrestrained suspension assembly. The top of the heat exchange tubes is movably suspended on the support rod via the free suspension assembly, allowing the heat exchange tubes to move relative to the support rod and the top frame base. The flexible buffer balance pads are located on both sides of the lower end of the heat exchange tubes and are positioned at the corresponding striking points of the high-frequency vibrator on the heat exchange tubes.

[0007] The free suspension assembly includes a suspension cable and a first sheath tube. The first sheath tube has an arc-shaped tubular structure and is fitted onto the upper end of the heat exchanger tube. The first sheath tube is suspended from the support rod by the suspension cable, forming a cable-type structure, which allows the heat exchanger tube to bear the weight and move relative to the support rod through the cable-type structure.

[0008] The free suspension assembly includes a spreader beam and a second sheath tube. The second sheath tube is a tubular structure and is fitted onto the upper part of the heat exchange tube. The spreader beam is horizontally overlapped between two adjacent second sheath tubes to form an inverted U-shaped structure. The support rod passes through the inverted U-shaped structure, forming a spreader beam suspension structure, which allows the heat exchange tube to bear the weight through the spreader beam cantilever structure and move relative to the support rod.

[0009] The free suspension assembly includes a first sheath tube and an arc-shaped support part. The first sheath tube has an arc-shaped tubular structure and is fitted onto the upper end of the heat exchanger tube. The arc-shaped support part is mounted on the support rod, and the top of the arc-shaped support part has an arc-shaped surface structure. The heat exchanger tube is suspended on the support rod through the first sheath tube, so that the arc-shaped surface structure of the arc-shaped support part contacts the first sheath tube, forming a double arc contact structure. This allows the heat exchanger tube to bear the weight and move relative to the support rod through the double arc contact structure.

[0010] The unrestrained suspension assembly includes a movable plate chain, a first suspension rod, a second suspension rod, and a swing connector; the upper end of the first suspension rod is fixedly connected to the top frame seat, and the lower end of the first suspension rod is swayably connected between the upper ends of a pair of movable plate chains through the swing connector; the upper end of the second suspension rod is swayably connected between the lower ends of a pair of movable plate chains through the swing connector, and the lower end of the second suspension rod is fixedly connected to a support rod, allowing the support rod to move relative to the top frame seat through the swing connector.

[0011] The unrestrained suspension assembly includes suspension springs, and the support rod is suspended below the top frame seat by several suspension springs.

[0012] The heat exchange pipes are connected to expansion joints at the steam and water inlet and outlet, and the expansion joints are installed on the outer wall of the boiler furnace.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. Because the present invention is equipped with a free suspension assembly, the heat exchange tubes are movably connected to the support rod through the free suspension assembly. Various methods such as steel cables, spreader beams, or nested large and small arcs can be used to achieve relative movement between the heat exchange tubes and the support rods, avoiding rigid connections and eliminating stress concentration points. When the heat exchange tubes are subjected to high-frequency vibration, the stress is fully buffered and released through natural shaking and swinging. This fundamentally and thoroughly solves the problem of tube bursting and leakage caused by brittle fatigue cracking due to stress concentration caused by high-frequency vibration.

[0014] 2. Because the present invention is equipped with an unrestrained suspension assembly, the support rod is movably connected to the top frame seat through the unrestrained suspension assembly. The relative movement of the heat exchange tube and the support rod relative to the top frame seat is realized by the swing of the swing connector, which avoids rigid connection, eliminates stress concentration points, and further improves the stress buffering and release effect of the heat exchange tube when subjected to high frequency vibration, effectively avoiding the occurrence of fatigue cracking, tube bursting and leakage of heat exchange tube.

[0015] 3. Because the present invention is equipped with a flexible buffer balance pad and an expansion joint, the entire heat exchange pipe is formed into a flexible structure. The deformation of the flexible buffer balance pad and the expansion joint further improves the stress buffering, stress relaxation and stress release potential of the flexible suspension shock absorption device.

[0016] This invention forms a quadruple flexible structure by using a free suspension component, an unrestrained suspension component, a flexible buffer balance pad, and an expansion joint. The matching method of the quadruple flexible connection replaces the traditional rigid connection structure between the heat exchange tubes, the top frame seat, and the support rod. It has the ability to buffer stress, relax stress, and release stress. While ensuring efficient heat exchange function, it can completely eliminate the failure problem of brittle fatigue cracking of the heat exchange tubes, and also ensure the effect of high-frequency vibration impact to remove ash, scale, and dust. Attached Figure Description

[0017] Figure 1 This is a front view of the existing technology boiler heat exchanger rigid hanging frame welded structure; Figure 2 This is a front view of the flexible suspension vibration damping device for boiler heat exchangers of the present invention; Figure 3 This is a schematic diagram of the free suspension component (suspension cable structure) in the flexible suspension vibration damping device for boiler heat exchangers of the present invention; Figure 4 This is a front view of the free suspension component (flat beam structure) in the flexible suspension vibration damping device for boiler heat exchangers of the present invention; Figure 5 This is a front view of the free suspension component (double arc contact structure) in the flexible suspension vibration damping device for boiler heat exchangers of the present invention; Figure 6This is a schematic diagram of the unrestrained suspension component in the flexible suspension damping device for boiler heat exchangers of the present invention.

[0018] In the diagram, 1 is the heat exchanger tube, 11 is the expansion joint, 12 is the shock absorber, 2 is the top frame seat, 3 is the support rod, 4 is the flexible buffer balance pad, 51 is the suspension cable, 52 is the first sheath, 53 is the spreader beam, 54 is the second sheath, 55 is the arc-shaped support, 61 is the movable plate chain, 62 is the first hanging rod, 63 is the second hanging rod, 64 is the swing connector, 65 is the suspension spring, and 7 is the boiler furnace wall. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] Please see the appendix Figure 2 A flexible suspension vibration damping device for boiler heat exchangers includes a top frame seat 2, a support rod 3, a free suspension assembly, an unrestrained suspension assembly, and a flexible buffer balance pad 4. The support rod 3 is suspensively suspended below the top frame seat 2 via the unrestrained suspension assembly. The top of the heat exchange tube 1 is movably suspended on the support rod 3 via the free suspension assembly, allowing the heat exchange tube 1 to move relative to the support rod 3 and the top frame seat 2. The flexible buffer balance pad 4 is disposed on both sides of the lower end of the heat exchange tube 1 and is located at the corresponding striking points of the high-frequency vibrator on the heat exchange tube 1. During high-frequency vibration, the high-frequency vibrator strikes the flexible buffer balance pad 4, utilizing the deformation of the flexible buffer balance pad 4 to buffer and release the vibration stress. The heat exchange tube 1 is freely suspended on the support rod 3 by the free suspension assembly, forming a flexible suspension structure without rigid restraint. At the same time, the support rod 3 can be swung and suspended on the top frame seat 2 by the unrestrained suspension assembly, which can further help the heat exchange tube 1 release stress. Without the need for rigid connection, the traditional fixed force-bearing mode is changed to a movable force-bearing mode, eliminating stress concentration points and buffering and releasing stress.

[0021] Please see the appendix Figure 2 and attached Figure 3 The free suspension assembly includes a suspension cable 51 and a first sheath tube (or sheath plate) 52. The first sheath tube 52 has an arc-shaped tubular structure and is fitted onto the upper end of the heat exchanger tube 1. The first sheath tube (or sheath plate) 52 is suspended from the support rod 3 by the suspension cable 51, forming a cable-stayed structure. This allows the heat exchanger tube 1 to bear weight and move relative to the support rod 3 through the cable-stayed structure. The suspension cable 51 enables the free suspension of the heat exchanger tube 1 without creating rigid constraints on it, thus avoiding stress concentration at rigid welded joints that could lead to cracking and tube rupture / leakage. Preferably, the suspension cable 51 can be made of steel cable or spring, providing good load-bearing capacity.

[0022] Please see the appendix Figure 4The free suspension assembly includes a spreader beam 53 and a second sheath tube (or sheath plate) 54. The second sheath tube 54 is a tubular structure and is fitted onto the upper part of the heat exchanger tube 1. The spreader beam 53 is laterally overlapped between two adjacent second sheath tubes (or sheath plates) 54 to form an inverted U-shaped structure. The support rod 3 passes through the inverted U-shaped structure, forming a spreader beam suspension structure, allowing the heat exchanger tube 1 to bear weight and move relative to the support rod 3 through the spreader beam suspension structure. The inverted U-shaped structure enables the heat exchanger tube 1 to be freely suspended on the support rod 3, without forming a rigid constraint on the heat exchanger tube 1, thus avoiding stress concentration at the rigid welded parts, which could lead to cracking and tube rupture and leakage.

[0023] Please see the appendix Figure 5 The free suspension assembly includes a first sheath tube (or sheath plate) 52 and an arc-shaped support part 55. The first sheath tube 52 has an arc-shaped tubular structure and is fitted onto the upper end of the heat exchanger tube 1. The arc-shaped support part 55 is mounted on the support rod 3, and the top of the arc-shaped support part 55 has an arc-shaped surface structure. The heat exchanger tube 1 is suspended on the support rod 3 through the first sheath tube (or sheath plate) 52, so that the arc-shaped support part 55 is in contact with the first sheath tube (or sheath plate) 52, forming a double arc contact structure. This allows the heat exchanger tube 1 to bear weight and move relative to the support rod 3 through the double arc contact structure. The relative movement is achieved by using the structure of a large arc between the arc-shaped support part 55 and the first sheath tube (or sheath plate) 52, thereby realizing the free suspension of the heat exchanger tube 1 on the support rod 3. This avoids the formation of rigid constraints on the heat exchanger tube 1, preventing stress concentration at rigid welded parts that could lead to cracking and tube bursting. The first protective sleeve 52 can prevent wear and tear. When using it, it can be in the form of a tube, plate, gasket or other structures according to actual needs.

[0024] Please see the appendix Figure 6 The unrestrained suspension assembly includes a movable chain 61, a first suspension rod 62, a second suspension rod 63, and a swing connector 64. The upper end of the first suspension rod 62 is fixedly connected to the top frame seat 2, and the lower end of the first suspension rod 62 is swayably connected between the upper ends of a pair of movable chains 61 via the swing connector 64. The upper end of the second suspension rod 63 is swayably connected between the lower ends of a pair of movable chains 61 via the swing connector 64, and the lower end of the second suspension rod 63 is fixedly connected to a support rod 3, allowing the support rod 3 to move relative to the top frame seat 2 via the swing connector 64. Preferably, the swing connector 64 can be a pin, allowing the movable chain 61 to swing relative to the first suspension rod 62 and the second suspension rod 63, thereby realizing the swing of the support rod 3 relative to the top frame seat 2.

[0025] Please see the appendix Figure 2The unrestrained suspension assembly includes suspension springs 65. The support rod 3 is suspended below the top frame seat 2 by several suspension springs 65. The elastic deformation and swing of the suspension springs 65 are used to buffer and dissipate the stress generated by vibration.

[0026] Please see the appendix Figure 2 The heat exchange pipe 1 is connected to the steam and water inlet and outlet with an expansion joint 11. The expansion joint 11 is set on the outer wall of the boiler furnace wall 7. The expansion joint 11 can adopt a telescopic structure to make the entire heat exchange pipe 1 form a flexible structure for further buffering and stress release.

[0027] Please see the appendix Figure 2 Preferably, a buffer damper 12 is connected between the steam and water inlet and outlet of the heat exchange pipe 1 and the inner wall of the boiler furnace wall 7. The buffer damper 12 can be a spring, and the elastic deformation of the buffer damper 12 is used to further buffer and dissipate the stress generated by the vibration.

[0028] Please see the appendix Figure 2 To be continued Figure 6 The working principle of this invention is as follows: When the lower end of the heat exchanger tube 1 is subjected to high-frequency rapping impact for ash and scale removal, the heat exchanger tube 1 will generate strong swaying vibration under the action of the free suspension component. When the heat exchanger tube 1 transmits the shock wave from the lower end rapping source to the load-bearing area at the top of the tube about 4-6 meters away, the stress concentration point is eliminated because the top of the heat exchanger tube 1 is suspended by the free suspension component. This allows for the rapid and automatic buffering and release of all the impact stress transmitted from the bottom up.

[0029] At the same time, under the action of the unrestrained suspension assembly, the swing of the swing connector 64 further assists the heat exchange tube 1 in releasing stress, so that the suspension structure of the entire heat exchange tube 1 can fully absorb the alternating impact vibration energy during high-frequency rapping, improve the system's stress mode, eliminate vibration fatigue, and significantly extend its service life.

[0030] In addition, during high-frequency rapping, when the high-frequency rapper impacts the flexible buffer balance pad 4 at the striking part of the heat exchange tube 1, expansion joints 11 are configured at the steam and water inlet and outlet of the heat exchange tube 1, and the entire heat exchange tube 1 forms a flexible structure, further improving the potential for stress buffering, stress relaxation and stress release.

[0031] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A flexible suspension vibration damping device for boiler heat exchangers, characterized in that: It includes a top frame base (2), a support rod (3), a free suspension assembly, an unrestrained suspension assembly, and a flexible buffer balance pad (4); the support rod (3) is swung and suspended below the top frame base (2) through the unrestrained suspension assembly, and the top of the heat exchange tube (1) is movably suspended on the support rod (3) through the free suspension assembly, so that the heat exchange tube (1) can move relative to the support rod (3) and the top frame base (2); the flexible buffer balance pad (4) is set on both sides of the lower end of the heat exchange tube (1) and is located at the corresponding striking part of the high-frequency vibrator on the heat exchange tube (1); The unrestrained suspension assembly includes suspension springs (65), and the support rod (3) is suspended below the top frame seat (2) by several suspension springs (65). The heat exchange tube (1) is flexibly suspended on the support rod (3) by the free suspension assembly and suspended below the top frame seat (2) by the suspension spring (65), forming a flexible suspension structure without rigid restraint.

2. The flexible suspension vibration damping device for boiler heat exchangers according to claim 1, characterized in that: The free suspension assembly includes a suspension cable (51) and a first sheath (52). The first sheath (52) has an arc-shaped tubular structure and is fitted onto the top of the heat exchange pipe (1). The first sheath (52) is suspended on the support rod (3) by the suspension cable (51), forming a cable-type structure, so that the heat exchange pipe (1) can bear the weight and move relative to the support rod (3) through the cable-type structure.

3. The flexible suspension vibration damping device for boiler heat exchangers according to claim 1, characterized in that: The free suspension assembly includes a spreader beam (53) and a second sheath (54). The second sheath (54) is a tubular structure and is fitted onto the top of the heat exchange pipe (1). The spreader beam (53) is horizontally overlapped between two adjacent second sheaths (54) to form an inverted U-shaped structure. The support rod (3) passes through the inverted U-shaped structure to form a spreader beam suspension structure, so that the heat exchange pipe (1) can bear the weight through the spreader beam suspension structure and move relative to the support rod (3).

4. The flexible suspension vibration damping device for boiler heat exchangers according to claim 1, characterized in that: The free suspension assembly includes a first sheath tube (52) and an arc-shaped support part (55). The first sheath tube (52) has an arc-shaped tubular structure and is fitted onto the top of the heat exchange tube (1). The arc-shaped support part (55) is set on the support rod (3), and the top of the arc-shaped support part (55) has an arc surface structure. The heat exchange tube (1) is hung on the support rod (3) through the first sheath tube (52), so that the arc surface structure of the arc-shaped support part (55) is in contact with the first sheath tube (52), forming a double arc contact structure, so that the heat exchange tube (1) can bear the weight and move relative to the support rod (3) through the double arc contact structure.

5. The flexible suspension vibration damping device for boiler heat exchangers according to claim 1, characterized in that: The unrestrained suspension assembly includes a movable plate chain (61), a first suspension rod (62), a second suspension rod (63), and a swing connector (64). The upper end of the first suspension rod (62) is fixedly connected to the top frame seat (2), and the lower end of the first suspension rod (62) is swayably connected between the upper ends of a pair of movable plate chains (61) through the swing connector (64). The upper end of the second suspension rod (63) is swayably connected between the lower ends of a pair of movable plate chains (61) through the swing connector (64), and the lower end of the second suspension rod (63) is fixedly connected to the support rod (3), so that the support rod (3) can move relative to the top frame seat (2) through the swing connector (64).

6. The flexible suspension vibration damping device for boiler heat exchangers according to any one of claims 1 to 4, characterized in that: The heat exchange pipe (1) is connected to an expansion joint (11) at the steam and water inlet and outlet, and the expansion joint (11) is installed on the outer wall of the boiler furnace wall (7).

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