Monitoring device for wall temperature measuring point of back fire surface of water cooling wall

Abstract

The invention relates to the technical field of temperature measuring equipment, in particular to a monitoring device for a wall temperature measuring point of a fire-back surface of a water-cooled wall, which comprises a supporting sheet fixedly connected with a fire-back surface of a water-cooled wall tube, a blocking block fixedly penetrates through the supporting sheet, a temperature measuring element is fixedly arranged on the rear side wall of the supporting sheet, a shape memory alloy strip is fixedly arranged on the blocking block, and the shape memory alloy strip is fixedly connected with the water-cooled wall tube. A heat conduction copper sheet is fixedly arranged on the outer side wall of the shape memory alloy strip, and the shape memory alloy strip comprises a temperature transfer strip which fixedly penetrates through the plug block in the front-back direction, two forked strips which are integrally formed with the temperature transfer strip and extend towards the left side and the right side along the front side wall of the plug block respectively, and a special-shaped strip which deforms after being heated by steam and is attached to the inner wall of the water wall tube. The temperature of the heat conduction copper sheet is measured through the temperature measuring element, the fire facing surface temperature distribution of the water cooling wall tube can be indirectly calculated, and a basis is provided for boiler operation state evaluation; and when the shape memory alloy strip recovers the shape, the heat conduction copper sheet can be driven to recover and fit the inner wall of the water-cooled wall.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature measurement devices, and particularly to a monitoring device for the wall temperature measurement points on the backfire side of a water-cooled wall. Background Art

[0002] With the development of the new energy industry in China, the demand for flexible transformation and deep peak shaving in thermal power plants has been continuously increasing. The uneven distribution of the internal heat load in the boiler during design and operation, as well as the continuous change of the temperature of the water-cooled wall heating surface caused by repeated peak shaving, pose a potential threat to the safe operation of the boiler. In this case, the demand for monitoring the wall temperature of the boiler water-cooled wall in thermal power plants has been increasing, and various transformation projects for adding wall temperature measurement points have followed.

[0003] Chinese Utility Model with the publication number CN215637098U discloses a device for measuring the wall temperature of the fire side of a boiler water-cooled wall. The operation of installing and maintaining the thermocouple in this utility model is difficult, and situations such as improper installation are likely to occur, such as insufficient insertion depth and deviation in the installation position, which affect the temperature measurement accuracy. At the same time, the structure of the fire side tube body is damaged, reducing the service life of the water-cooled wall tube.

[0004] Chinese Invention with the publication number CN105403243B discloses a temperature and pressure measurement device on the combustion chamber water-cooled wall surface. In this invention, the temperature measurement tube has limited contact with the inner wall of the combustion chamber, and there is a situation where the temperature measurement point is affected by local high-temperature points or uneven combustion, and cannot truly reflect the overall temperature condition of the water-cooled wall. Summary of the Invention

[0005] The purpose of the present invention is to provide a monitoring device for the wall temperature measurement points on the backfire side of a water-cooled wall to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A monitoring device for the wall temperature measurement points on the backfire side of a water-cooled wall, including a support piece fixedly connected to the backfire side of the water-cooled wall tube. A plug block is fixedly penetrated through the support piece in the front-rear direction. A temperature measurement hole matching the plug block is opened on the backfire side of the water-cooled wall tube. A temperature measurement element is fixedly provided on the rear side wall of the support piece. A shape memory alloy strip is fixedly provided on the plug block. After being heated and restored, the shape memory alloy strip can fit around the inner wall of the water-cooled wall tube. A heat-conducting copper sheet is fixedly provided on the outer side wall of the shape memory alloy strip and at the longitudinal center of the shape memory alloy strip. The heat-conducting copper sheet abuts against the detection end of the temperature measurement element. The shape memory alloy strip includes a heat transfer strip fixedly penetrated through the plug block in the front-rear direction, two bifurcated strips integrally formed with the heat transfer strip and extending from the front side wall of the plug block to the left and right sides respectively, and a special-shaped strip disposed inside the water-cooled wall tube and deformed by steam heating to fit the inner wall of the water-cooled wall tube. The special-shaped strip includes a superior arc strip disposed on the front side of the axis of the water-cooled wall tube, two arc transition strips integrally formed with both ends of the superior arc strip respectively, a straight strip integrally formed with the arc transition strip and extending in the front-rear direction, and an inferior arc compression strip integrally formed with the straight strip and connecting the bifurcated strip; The convex arc side of the superior arc strip and the concave arc side of the inferior arc compression strip both face the axis of the water-cooled wall tube.

[0007] Optionally, the front side wall of the plug block is a circular arc structure that fits the inner wall of the water-cooled wall tube. The rear side wall of the bifurcated strip is welded to the front side wall of the plug block. The symmetry center of the two bifurcated strips and the center of the circle of the superior arc strip are on the same straight line.

[0008] Optionally, the maximum distance between the front end of the inferior arc compression strip and the inner wall of the water-cooled wall tube is ≤2 mm. A spindle-shaped space is enclosed between the two inferior arc compression strips.

[0009] Optionally, the thickness of the shape memory alloy strip is 3 mm, and the As temperature of the shape memory alloy strip is 150 °C ± 5 °C.

[0010] Optionally, the shape memory alloy strip is a copper-aluminum-nickel shape memory alloy.

[0011] Optionally, the thickness of the heat-conducting copper sheet is 1 mm. A liquid accumulation cavity is provided on the inner wall of the special-shaped strip and at the center in the width direction of the special-shaped strip. The maximum depth of the liquid accumulation cavity is 1.0 - 1.5 mm.

[0012] Optionally, a first arc transition is provided between the bifurcated strip and the inferior arc compression strip. The central angle corresponding to the first arc transition is 40° - 50°. A second arc transition is provided between the straight strip and the inferior arc compression strip. The central angle corresponding to the second arc transition is 130° - 150°.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention is convenient to install, economical and efficient. By using the heat-conducting copper sheet as the heat-conducting element inside the water-cooled wall tube and measuring the temperature of the heat-conducting copper sheet through the temperature measuring element, the temperature distribution on the fire-facing surface of the water-cooled wall tube can be indirectly calculated, providing a basis for evaluating the operation state of the boiler; by covering the heat-conducting copper sheet with the shape memory alloy strip, it is possible to prevent steam from directly contacting the heat-conducting copper sheet and affecting the heat-conducting accuracy, and when the shape memory alloy strip returns to its shape, it can drive the heat-conducting copper sheet to recover and fit the inner wall of the water-cooled wall together, ensuring the accuracy of water-cooled wall temperature measurement; 2. The present invention provides a liquid accumulation space for the shape memory alloy strip through the liquid accumulation cavity, reducing the steam flow rate in the vicinity. At the same time, the shape memory alloy strip protrudes from the inner wall of the water-cooled wall, increasing the turbulence when the fluid or steam passes through the shape memory alloy strip, thereby reducing the heat carried away by the steam, making the temperatures of the heat-conducting copper sheet and the shape memory alloy strip closer to the temperature of the fire-facing side of the water-cooled wall, and improving the monitoring accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic structural diagram of the present invention; Figure 2 is Figure 1 a magnified schematic structural diagram of part A in Figure 3 is a schematic structural diagram of the shape memory alloy strip in the present invention; Figure 4 is Figure 1 a schematic structural diagram of the shape memory alloy strip expanding after being thermally conducted by steam in

[0015] In the figure: 1, water-cooled wall tube; 2, supporting piece; 3, plug block; 4, temperature measuring hole; 5, shape memory alloy strip; 501, temperature transfer strip; 502, bifurcated strip; 503, major arc strip; 504, arc transition strip; 505, straight strip; 506, minor arc compression strip; 507, liquid accumulation cavity; 508, through hole; 6, temperature measuring element; 7, heat-conducting copper sheet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0017] Embodiment: Please refer to Figures 1 to 4 , the present invention provides a monitoring device for the wall temperature measurement point on the back fire side of the water-cooled wall, including a supporting piece 2 fixedly connected to the back fire side of the water-cooled wall tube 1. A plug block 3 is fixedly penetrated through the supporting piece 2 in the front-rear direction. A temperature measuring hole 4 matching the plug block 3 is opened on the back fire side of the water-cooled wall tube 1. The front end of the plug block 3 is inserted into the temperature measuring hole 4, and the front side wall of the plug block 3 is a circular arc structure matching the inner wall of the water-cooled wall tube 1. Both the supporting piece 2 and the plug block 3 are made of materials with high temperature resistance, corrosion resistance, and low thermal conductivity. A temperature measuring element 6 is fixedly provided on the rear side wall of the supporting piece 2, and the temperature measuring element 6 is one of a thermocouple, a thermal resistor, and a thermistor.

[0018] A shape memory alloy strip 5 is fixedly provided on the blocking block 3. After the shape memory alloy strip 5 is heated and restored, it can fit around the inner wall of the water-cooled wall tube 1. A heat-conducting copper sheet 7 is fixedly provided on the outer side wall of the shape memory alloy strip 5 and at the longitudinal center of the shape memory alloy strip 5. Specifically, a groove that matches the heat-conducting copper sheet 7 is formed on the outer side wall of the shape memory alloy strip 5. After the heat-conducting copper sheet 7 is fixed on the shape memory alloy strip 5, the outer side wall of the heat-conducting copper sheet 7 is flush with the outer side wall of the shape memory alloy strip 5. The heat-conducting copper sheet 7 abuts against the detection end of the temperature measuring element 6.

[0019] The shape memory alloy strip 5 includes a heat-transfer strip 501 that fixedly penetrates through the blocking block 3 in the front-rear direction, two bifurcated strips 502 that are integrally formed with the heat-transfer strip 501 and extend from the front side wall of the blocking block 3 to the left and right sides respectively, and a special-shaped strip that is arranged in the water-cooled wall tube 1 and deforms after being heated by steam and fits against the inner wall of the water-cooled wall tube 1. Among them, the special-shaped strip includes a superior arc strip 503 arranged in front of the axis of the water-cooled wall tube 1, two arc transition strips 504 that are integrally formed with the two ends of the superior arc strip 503 respectively, a straight strip 505 that is integrally formed with the arc transition strip 504 and extends in the front-rear direction, and an inferior arc compression strip 506 that is integrally formed with the straight strip 505 and connects the bifurcated strip 502. The convex arc side of the superior arc strip 503 and the concave arc side of the inferior arc compression strip 506 both face the axis of the water-cooled wall tube 1.

[0020] In the present invention, the shape memory alloy strip 5 and the heat-conducting copper sheet 7 are used as heat-conducting elements in the water-cooled wall tube, and the temperature of the heat-conducting copper sheet 7 is measured by the temperature measuring element, so that the temperature distribution on the fire-facing surface of the water-cooled wall tube can be indirectly calculated, providing a basis for evaluating the operation state of the boiler.

[0021] Based on the above embodiments, in this embodiment, the rear side wall of the bifurcated strip 502 is welded to the front side wall of the blocking block 3, and the symmetry center of the two bifurcated strips 502 is on the same straight line as the center of the circle of the superior arc strip 503. A first arc transition is provided between the bifurcated strip 502 and the inferior arc compression strip 506, and the central angle corresponding to the first arc transition is 40°-50°. A second arc transition is provided between the straight strip 505 and the inferior arc compression strip 506, and the central angle corresponding to the second arc transition is 130°-150°.

[0022] The maximum distance between the front end of the inferior arc compression strip 506 and the inner wall of the water-cooled wall tube 1 is ≤2 mm, and the front end of the inferior arc compression strip 506 does not contact the water-cooled wall tube 1. The above distance provides space for the deformation of the inferior arc compression strip 506, avoiding friction between the inferior arc compression strip 506 and the water-cooled wall tube 1 during the initial deformation process. A spindle-shaped space is enclosed between the two inferior arc compression strips 506, providing space for synchronously squeezing the two inferior arc compression strips 506 towards each other, facilitating the inferior arc compression strip 506 to pass through the temperature measuring hole 4.

[0023] Based on the above embodiments, in this embodiment, the thickness of the shape memory alloy strip 5 is 3 mm, the thickness of the heat-conducting copper sheet 7 is 1 mm, and the width of the heat-conducting copper sheet 7 is 1 / 3 of the width of the special-shaped strip. The As temperature of the shape memory alloy strip 5 is 150°C ± 5°C. Specifically, the shape memory alloy strip is preferably a copper-aluminum-nickel shape memory alloy. Initially, the shape memory alloy strip 5 is heated to a temperature lower than its As temperature. At this time, the shape memory alloy strip 5 is in the Figure 1 state. In this state, with the help of the shape memory alloy strip 5, it can be compressed and deformed, and the shape memory alloy strip 5 can enter the water-cooled wall tube 1 through the temperature measurement hole 4. When the shape memory alloy strip 5 is heated by steam to a temperature above its As temperature, the shape memory alloy strip 5 deforms. Since the length of the two inferior-arc compression strips 506 in the special-shaped strip accounts for the largest proportion, the two inferior-arc compression strips 506 will simultaneously undergo reverse deformation and unfold the superior-arc strip 503 by pulling the straight strip 505, so that finally the special-shaped strip deforms and fits the inner wall of the water-cooled wall tube 1.

[0024] Therefore, when the water-cooled wall tube 1 is operating, the steam in the water-cooled wall tube 1 will heat the shape memory alloy strip 5, causing the shape memory alloy strip 5 to thermally expand. The thermal expansion of the shape memory alloy strip 5 will drive the heat-conducting copper sheet 7 to deform and fit the water-cooled wall tube 1, not only improving the heat transfer efficiency from the fire side to the back fire side of the water-cooled wall tube 1, but also enhancing the stability of the heat-conducting copper sheet 7 fixed on the water-cooled wall tube 1. The heat-conducting copper sheet 7 can directly obtain the heat on the fire side of the water-cooled wall tube 1 and conduct the heat to the back fire side for convenient temperature measurement, while not damaging the tube body on the fire side of the water-cooled wall tube 1 and extending the service life of the water-cooled wall tube 1. It should be noted that before the water-cooled wall tube 1 operates, the boiler water circulation pump needs to be started to form an operation mode of establishing water circulation first and then igniting. When the steam temperature in the water-cooled wall tube 1 is higher than 150°C, that is, higher than the As temperature of the shape memory alloy strip 5, the shape memory alloy strip 5 is heated and deformed into the Figure 4 state. At this time, the outer wall of the heat-conducting copper sheet 7 perfectly fits the inner wall of the water-cooled wall tube 1, and temperature monitoring can be carried out.

[0025] Based on the above embodiments, in this embodiment, a liquid accumulation cavity 507 is provided on the inner wall of the special-shaped strip and at the center in the width direction of the special-shaped strip. The maximum depth of the liquid accumulation cavity 507 is 1.0 - 1.5 mm. The present invention provides a liquid accumulation space for the shape memory alloy strip 5 through the liquid accumulation cavity 507, reducing the steam flow rate nearby, thereby reducing the heat carried away by the steam, making the temperatures of the heat-conducting copper sheet 7 and the shape memory alloy strip 5 closer to the temperature on the fire side of the water-cooled wall, and improving the monitoring accuracy.

[0026] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A monitoring device for the wall temperature measurement points on the backfire side of the water-cooled wall, characterized in that, It includes a support piece (2) fixedly connected to the backfire surface of the water-cooled wall tube (1). A blocking block (3) is fixedly penetrated through the support piece (2) in the front-back direction. A temperature measurement hole (4) matching the blocking block (3) is opened on the backfire surface of the water-cooled wall tube (1). A temperature measurement element (6) is fixedly arranged on the rear side wall of the support piece (2). A shape memory alloy strip (5) is fixedly arranged on the blocking block (3). After the shape memory alloy strip (5) is heated and restored, it can fit around the inner wall of the water-cooled wall tube (1). A heat-conducting copper sheet (7) is fixedly arranged on the outer side wall of the shape memory alloy strip (5) and at the longitudinal center of the shape memory alloy strip (5). The heat-conducting copper sheet (7) abuts against the detection end of the temperature measurement element (6). The shape memory alloy strip (5) includes a temperature transfer strip (501) fixedly penetrated through the blocking block (3) in the front-back direction, two bifurcated strips (502) integrally formed with the temperature transfer strip (501) and respectively extending from the front side wall of the blocking block (3) to the left and right sides, and a special-shaped strip arranged in the water-cooled wall tube (1) and deformed by steam heating to fit the inner wall of the water-cooled wall tube (1); The special-shaped strip includes a superior arc strip (503) arranged in front of the axis of the water-cooled wall tube (1), two arc transition strips (504) respectively integrally formed with both ends of the superior arc strip (503), a straight strip (505) integrally formed with the arc transition strip (504) and extending in the front-back direction, and an inferior arc compression strip (506) integrally formed with the straight strip (505) and connecting the bifurcated strips (502); The convex arc side of the superior arc strip (503) and the concave arc side of the inferior arc compression strip (506) both face the axis of the water-cooled wall tube (1).

2. The monitoring device for the wall temperature measurement points on the backfire side of the water wall according to claim 1, characterized in that, The front side wall of the blocking block (3) is a circular arc structure matching the inner wall of the water-cooled wall tube (1). The rear side wall of the bifurcated strip (502) is welded to the front side wall of the blocking block (3). The symmetry center of the two bifurcated strips (502) is on the same straight line as the center of the circle of the superior arc strip (503).

3. The monitoring device for the wall temperature measurement points on the backfire side of the water-cooled wall according to claim 1, characterized in that, The maximum distance between the front end of the inferior arc compression strip (506) and the inner wall of the water-cooled wall tube (1) is ≤2 mm. A spindle-shaped space is enclosed between the two inferior arc compression strips (506).

4. The monitoring device for the wall temperature measurement points on the backfire side of the water-cooled wall according to claim 1, characterized in that, The thickness of the shape memory alloy strip (5) is 3 mm, and the As temperature of the shape memory alloy strip (5) is 150 °C ± 5 °C.

5. The monitoring device for the wall temperature measuring points on the backfire side of the water-cooled wall according to claim 4, characterized in that, The shape memory alloy strip is a copper-aluminum-nickel shape memory alloy.

6. The monitoring device for the wall temperature measurement points on the backfire side of the water-cooled wall according to claim 4, characterized in that, The thickness of the heat-conducting copper sheet (7) is 1 mm. A liquid accumulation cavity (507) is opened on the inner wall of the special-shaped strip and at the width direction center of the special-shaped strip. The maximum depth of the liquid accumulation cavity (507) is 1.0 - 1.5 mm.

7. The monitoring device for the wall temperature measurement points on the backfire side of the water-cooled wall according to claim 1, characterized in that, A first arc transition is provided between the bifurcated strip (502) and the inferior arc compression strip (506), and the central angle corresponding to the first arc transition is 40° - 50°. A second arc transition is provided between the straight strip (505) and the inferior arc compression strip (506), and the central angle corresponding to the second arc transition is 130° - 150°.

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