A sliding clamp for adjusting the flatness of the boiler heating surface tube screen and the boiler heating surface tube screen

Abstract

A sliding clamp for adjusting the flatness of a boiler heating surface tube screen and a boiler heating surface tube screen provided by the present invention include two sliding devices with the same structure. The sliding device is of a cylindrical structure, and its radial cross-section is a rectangular spiral. The two sliding devices are sleeved with each other along the trajectory of the spiral. The central ends of the two sliding devices are in contact with each other, and the free ends of the two sliding devices are arranged in parallel and extend to two adjacent pipes respectively. The two sliding devices are sleeved with each other through a clamping space and can move relatively. They are not easy to deform in a high-temperature working environment, and the two sliding blocks form a closed structure with each other and will not become disengaged. It can not only ensure the flatness of the tube screen but also does not block the free expansion of the tubes after heating, and has high working reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler pipes, and specifically to a sliding clamp for adjusting the flatness of a boiler tube panel. Background Art

[0002] The heating surface tube panels such as the high-temperature superheater, high-temperature reheater, and platen superheater of a power plant boiler are generally composed of multiple tubes (at least 10 and at most more than 20) arranged in parallel according to a certain pitch. The flatness of each group of tube panels should be ≤ 20 mm. Since the lengths of the tubes from the outermost circle to the innermost circle of each group of heating surface tube panels are different, the flue gas temperature on the outer wall of the tubes and the medium temperature inside the tubes are also different, and the expansion amounts of the tubes after being heated by the flue gas are also different. Therefore, in order to ensure that the tubes can freely expand after being heated, the adjacent tubes inside the heating surface tube panel cannot be welded together. In order to ensure that the flatness of the heating surface tube panel meets the standard and does not block the downward expansion amount generated by the temperature difference between adjacent tubes, 3 to 4 groups of sliding clamps will be arranged from top to bottom during the manufacture of the tube panel.

[0003] If the tube panel sliding clamp is damaged, it will cause the tube panel to be in chaos. The chaotic tube panel will cause serious coking on the tube panel. At the same time, problems such as excessive swinging amplitude of the tubes leading to material fatigue burst pipes, mechanical wear between the tubes resulting in wall thickness reduction, etc. will occur, and it greatly amplifies the damage caused by a single heating surface tube bursting in the furnace. The workload of overhauling and replacing tubes increases by more than ten times. The chaos of the tube panel is also one of the main reasons for the "four tubes" explosion of the boiler heating surface. Therefore, to maintain the flatness of the boiler heating surface tube panel in the furnace and the safe operation of the equipment, it is necessary to ensure the integrity and non-deformation failure of the sliding blocks between adjacent tubes.

[0004] Refer to Figure 1 and 2 , there are two existing mechanisms for arranging sliding blocks. One is that two single L-shaped structure sliding blocks are combined into a group of sliding clamps. After the two L-shaped steels are overlapped, a limiting plate is welded on one side of the L-shaped steel to prevent dislocation and tripping. However, in the lower part of the tube panel, due to the large downward elongation and expansion amount after heating, the thermal stress of the tube panel is also large. The limiting plate welded only on one side cannot resist the thermal stress deformation of the tube panel, and finally the sliding blocks are misaligned and tripped. The other is the corrugated card. The connection between the corrugated card and the tube panel is fixed by using a clamping block or plug welding in the middle of the wave. Under high-temperature working conditions, the corrugated card is directly heated by the flue gas, and its expansion amount is often greater than that of the fixed tube panel, making it difficult to be fixed firmly and easily loosening and falling off downward, resulting in its failure. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention provides a sliding clamp for adjusting the flatness of a boiler heating surface tube panel, which not only satisfies the free expansion between adjacent tubes, but also forms a closed loop and restricts each other to ensure that the flatness of the entire heating surface tube panel meets the requirement of ≤ 20 mm in the regulations.

[0006] The present invention is achieved through the following technical solutions:

[0007] A sliding clamp for adjusting the flatness of the tube screen of a boiler heating surface, comprising two sliding devices with the same structure. The sliding device is of a cylindrical structure, and its radial cross-section is a rectangular spiral. The two sliding devices are sleeved with each other along the trajectory of the spiral. The central ends of the two sliding devices are in contact with each other, and the free ends of the two sliding devices are arranged in parallel and extend to two adjacent pipes respectively.

[0008] Preferably, the sliding device includes a connecting arm and a U-shaped sliding rail. The connecting arm is located at the top of the sliding rail. One end of the connecting arm is connected to one end of the sliding rail, and the other end of the connecting arm passes through the top of the other end of the sliding rail.

[0009] Preferably, the sliding rail includes a first vertical wall and a second vertical wall that are parallel and spaced apart. The bottoms of the first vertical wall and the second vertical wall are connected by a bottom plate, and the upper end of the first vertical wall is higher than the upper end of the second vertical wall.

[0010] Preferably, the distance between the first vertical wall and the second vertical wall is greater than the width of the second vertical wall.

[0011] Preferably, the space between the upper end of the second vertical wall and the connecting arm is greater than the thickness of the bottom plate.

[0012] A tube screen for the heating surface of a boiler heating surface, comprising a plurality of heat pipes arranged at intervals. A sliding clamp is arranged between two adjacent heat pipes, and the end of each sliding device is fixedly connected to the heat pipe.

[0013] Preferably, the distance between two adjacent heat pipes is 20 mm - 35 mm.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects:

[0015] The sliding clamp for adjusting the flatness of the tube screen of a boiler heating surface provided by the present invention has two sliding devices sleeved with each other through a clamping space and can move relative to each other. It is not easily deformed in a high-temperature working environment, and the two sliding blocks form a closed structure and will not become unfastened. It can not only ensure the flatness of the tube screen but also does not block the free expansion of the tubes after heating, and has high working reliability. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of a conventional L-shaped sliding clamp;

[0017] Figure 2 It is a schematic structural diagram of a conventional corrugated sliding clamp;

[0018] Figure 3 It is an installation schematic diagram of the sliding clamp of the present invention;

[0019] Figure 4 Cross-sectional view of the sliding card of the present invention;

[0020] Figure 5 Front view of the sliding card of the present invention.

[0021] In the figure: 1. Sliding card; 2. Heat pipe; 3. Sliding device; Specific embodiments

[0022] The present invention will be further described in detail below with reference to the accompanying drawings. The following is an explanation of the present invention rather than a limitation.

[0023] Refer to Figure 3-5 , a sliding card for adjusting the flatness of the boiler heating surface tube panel, comprising two sliding devices 3 with the same structure. The sliding device is of a cylindrical structure, and its radial cross-section is a rectangular spiral. The two sliding devices are sleeved with each other along the trajectory of the spiral. The central ends of the two sliding devices are in contact with each other, and the free ends of the two sliding devices are arranged in parallel and extend to two adjacent pipes respectively.

[0024] The cross-section of the above-mentioned sliding device is a single-layer rectangular spiral, and its cross-section is in the shape of "G".

[0025] Each sliding device includes a horizontal connecting arm and a U-shaped sliding rail. The sliding rail includes a first vertical wall and a second vertical wall that are parallel and spaced apart. The bottoms of the first vertical wall and the second vertical wall are connected by a bottom plate. The upper end of the first vertical wall is higher than the upper end of the second vertical wall, and the distance between the first vertical wall and the second vertical wall is greater than the width of the second vertical wall.

[0026] The connecting arm is located at the top of the opening side of the sliding rail. One end of the connecting arm is connected to the top of the first vertical wall, and the other end passes through the top of the second vertical wall for connection with the heat pipe. A clamping space is formed between the first vertical wall and the second vertical wall, the bottom plate and the connecting arm.

[0027] The two sliding devices are respectively a first sliding device and a second sliding device. During installation, the second vertical wall of the first sliding device is located in the clamping space of the second sliding device to form a sliding card 1. The connecting arms of the two sliding devices are respectively located at the top and bottom of the sliding card, and the extending directions of the free ends of the two connecting arms are opposite, that is, they extend to two adjacent heat pipes respectively.

[0028] The material of the sliding card is 16Cr20Ni14Si2 heat-resistant alloy steel, with a length of 80 mm, a single side length of 25 mm, and a thickness of 5 mm. The specific dimensions can be slightly adjusted according to the actual situation on site. This sliding card is suitable for adjusting the flatness of the small pitch tube panel, that is, the tube panel with a pitch between adjacent tubes greater than 20 mm and less than 35 mm.

[0029] A sliding clamp for adjusting the flatness of the boiler heating surface tube screen provided by the present invention. Two sliding devices are sleeved with each other through a clamping space and can move relative to each other. They are not easily deformed under high-temperature working environments. The two sliding blocks form a closed structure and will not become disengaged. It can not only ensure the flatness of the tube screen but also does not block the free expansion of the tubes after heating, with high working reliability.

[0030] Secondly, each sliding device has only one welding point with the heat pipe, reducing the welding workload. The connection of each group of sliding clamps to the tubes now has the number of welds reduced from 3 to 2. Especially for high-alloy material tubes with extremely strict welding requirements, the welding workload is reduced by one-third. At the same time, it also reduces the tube leakage and furnace shutdown caused by possible welding quality problems. The structures and sizes of the two sliding devices are exactly the same, which will greatly reduce the processing workload and lower the processing cost and spare parts cost of the sliding clamp.

[0031] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention fall within the protection scope of the claims of the present invention.

Claims

1. A sliding clamp for adjusting the flatness of the boiler heating surface tube screen, characterized in that It includes two sliding devices with the same structure. The sliding device is of a cylindrical structure, and its radial cross-section is a rectangular helix. The two sliding devices are sleeved with each other along the helix trajectory. The central ends of the two sliding devices are in contact with each other, and the free ends of the two sliding devices are arranged in parallel and extend to two adjacent pipes respectively; The sliding device includes a horizontal connecting arm and a U-shaped sliding rail. The connecting arm is located at the top of the sliding rail. One end of the connecting arm is connected to one end of the sliding rail, and the other end of the connecting arm passes through the top of the other end of the sliding rail; The sliding rail includes a first vertical wall and a second vertical wall that are parallel and spaced apart. The bottoms of the first vertical wall and the second vertical wall are connected by a bottom plate, and the upper end of the first vertical wall is higher than the upper end of the second vertical wall.

2. The sliding clamp for adjusting the flatness of the boiler heating surface tube screen according to claim 1, wherein The distance between the first vertical wall and the second vertical wall is greater than the width of the second vertical wall.

3. The sliding clamp for adjusting the flatness of the boiler heating surface tube screen according to claim 1, wherein, The space between the upper end of the second vertical wall and the connecting arm is greater than the thickness of the bottom plate.

4. A boiler heating surface tube screen, characterized in that, It includes a plurality of heat pipes arranged at intervals. A sliding card according to any one of claims 1-3 is arranged between two adjacent heat pipes. The end of each sliding device is fixedly connected to the heat pipe.

5. A boiler heating surface tube screen according to claim 4, characterized in that, The distance between two adjacent heat pipes is 20 mm - 35 mm.

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