A device and method for zoned temperature control during heat treatment of headers in thermal power plants.

Abstract

This invention provides a device and method for zoned temperature control during heat treatment of a power plant header. The power plant header includes a main pipeline and a connecting pipe seat, with the connecting pipe seat installed on the side wall of the main pipeline. Multiple heating zones are provided on the main pipeline. Zone A is designated as the location where the connecting pipe seat is installed. Four additional zones are further defined around Zone A, numbered B, C, D, and E from the inside out. Each zone is equipped with an independent heating element. This invention provides zoned heating of the main pipeline with high controllability, thereby ensuring precise control of the weld heat treatment temperature.

Description

Technical Field

[0001] This invention belongs to the field of heat treatment technology, specifically a device and method for zoned temperature control during heat treatment of headers in thermal power plants. Background Technology

[0002] In thermal power plants, main steam pipes, reheat steam pipes, branch pipes, drain pipes, sampling pipes, and temperature jackets of boilers are generally equipped with connecting fittings. These fittings serve as transitional components connecting the main pipes and branch pipes. The connecting fittings are typically welded to the main pipes, forming a fillet weld. After welding, heat treatment is usually performed to eliminate residual stress in the weld joint and improve its microstructure and properties. The general process flow is as follows: install thermocouples → arrange heating devices → wrap with insulation cotton → set heat treatment parameters → perform heat treatment.

[0003] In existing technologies, when performing heat treatment on fillet welds of pipe fittings, flexible ceramic resistance heating elements are generally used for auxiliary heating of the main pipeline and heating of the fillet weld. While this heating method can effectively heat treat fillet welds, we have found that it still has certain shortcomings in practical applications, such as:

[0004] The above heating method does not provide precise control over the heat treatment temperature. Due to the large difference in wall thickness and pipe diameter between the main and branch pipes, the weld temperature on the side closer to the main pipe is low while the temperature on the other side is high. Using flexible ceramic resistance heating elements alone results in fewer controllable variables, making it difficult to accurately control the temperature of each zone of the main pipe and the connecting pipe seat. This leads to uneven heat treatment temperature and affects the heat treatment effect. Summary of the Invention

[0005] The purpose of this invention is to provide a device and method for zoned temperature control during the heat treatment of headers in thermal power plants, which solves the problem of uneven temperature and poor heat treatment effect in existing methods for heat treatment of fillet welds of headers.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for zoned temperature control during heat treatment of a header in a thermal power plant, wherein the header includes a main pipeline and a connecting pipe seat, and the connecting pipe seat is installed on the side wall of the main pipeline;

[0008] The main pipeline is equipped with multiple heating zones. The installation location of the pipe fitting is designated as Zone A. Centered on Zone A, there are four additional zones, which are designated as Zone B, Zone C, Zone D, and Zone E from the inside out.

[0009] Each zone is equipped with an independent heating element.

[0010] Preferably, far-infrared ceramic heating elements are installed in areas A and C, an auxiliary heating element is installed in area E, an inner medium-frequency induction line is installed in area B, and an outer medium-frequency induction line is installed in area D.

[0011] Preferably, each zone is also provided with a thermocouple.

[0012] Preferably, thermal insulation material is provided between the outer wall of the main pipe in zones B and D and the heating element.

[0013] Preferably, it also includes auxiliary components for auxiliary partitioning of the main pipeline.

[0014] Preferably, the auxiliary component includes a control cabinet, on which a plurality of U-shaped rods are arranged along its axial direction, and the U-shaped rods are slidably connected to the control cabinet;

[0015] The U-shaped rods are mounted on the main pipeline; the distance between two adjacent U-shaped rods corresponds to the nine zones of the main pipeline.

[0016] Preferably, the inner cavity of the control cabinet is also provided with an adjustment mechanism for adjusting the position of the U-shaped rod.

[0017] Preferably, it also includes an auxiliary mounting component for assisting in the installation of the heating element.

[0018] Preferably, the auxiliary mounting component includes a steel strip, one end of which is fixedly fitted with a locking sleeve, and the other end of which is bent and inserted into a slot opened on the locking sleeve; at the same time, a retaining sleeve is fitted on the steel strip for mounting the heating element.

[0019] A method for zoned temperature control during heat treatment of headers in thermal power plants includes the following steps:

[0020] Step 1: Divide the main pipeline into zones. The installation location of the pipe fitting is designated as Zone A. Centered on Zone A, there are four zones: Zone B, Zone C, Zone D, and Zone E, which are designated from the inside out.

[0021] Step 2: Install far-infrared ceramic heating elements in areas A and C, install auxiliary heating elements in area E, install inner medium-frequency induction wires in area B, install outer medium-frequency induction wires in area D, and install far-infrared ceramic heating ropes on the connector base.

[0022] Step 3: Control the far-infrared ceramic heating element, auxiliary heating element, inner medium-frequency induction line, outer medium-frequency induction line and far-infrared ceramic heating rope to heat the main pipeline in sections.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] The present invention provides a device for zoned temperature control during heat treatment of headers in thermal power plants. The main pipeline is divided into nine zones: A, B, C, D, and E, and the main pipeline is heated in zones with high controllability, thereby ensuring precise control of the heat treatment temperature of the weld.

[0025] Furthermore, by using auxiliary components to partition the main pipeline, not only is the installation efficiency high, but the installation errors are also greatly reduced, thus improving the heat treatment effect.

[0026] Furthermore, the main pipe and connector can be heated in zones by means of an inner medium-frequency induction line, a far-infrared ceramic heating element, an outer medium-frequency induction line, an auxiliary heating element, and a far-infrared ceramic heating rope. This achieves localized heating while ensuring the uniformity of the main heating zone. The pipe joints obtained by this heat treatment have good mechanical properties and service life. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the heat treatment process according to the present invention;

[0028] Figure 2 This is a schematic diagram of the partitioning of the main pipeline of the present invention;

[0029] Figure 3 This is an enlarged schematic diagram of the control cabinet portion of the present invention;

[0030] Figure 4 This is a cross-sectional view of the control cabinet portion of the present invention;

[0031] Figure 5 For the present invention Figure 4 Enlarged view of point A in the middle;

[0032] Figure 6 This is an enlarged schematic diagram of the steel strip portion of the present invention;

[0033] Figure 7 This is a cross-sectional view of the card sleeve portion of the present invention;

[0034] Figure 8 This is a cross-sectional view of the locking sleeve portion of the present invention.

[0035] In the diagram: 1. Main pipe; 2. Connector; 3. Inner medium-frequency induction wire; 4. Far-infrared ceramic heating element; 5. Outer medium-frequency induction wire; 6. Auxiliary heating element; 7. Far-infrared ceramic heating rope; 8. Control cabinet; 9. U-shaped rod; 10. Vertical shaft; 11. Guide groove; 12. Rotating roller; 13. Rotating shaft; 14. Worm gear; 15. Worm; 16. Knob; 17. Sleeve; 18. Steel strip; 19. Groove; 20. First protrusion; 21. First pressure plate; 22. First plate cavity; 23. First spring; 24. Locking sleeve; 25. Slot; 26. Second protrusion; 27. Second pressure plate; 28. Second plate cavity; 29. ​​Second spring; 30. Nut; 31. Lead screw; 32. Control button. Detailed Implementation

[0036] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0037] Example 1:

[0038] Please see Figure 1 and Figure 2 This embodiment provides a method for zoned temperature control during heat treatment of headers in thermal power plants, comprising the following steps:

[0039] Step 1: Using the installation point of connector 2 as the midpoint, divide the main pipeline 1 into sections, such as... Figure 2 As shown, the main pipeline 1 is divided into nine zones: A, B1, B2, C1, C2, D1, D2, E1, and E2.

[0040] Step 2: Install thermocouples in areas A, B1, B2, C1, C2, D1, and D2 respectively. In this embodiment, the thermocouples are spot-welded using energy storage welding. After spot welding, gently shake the base of the thermocouple to ensure that the spot weld is firm and will not fall off.

[0041] Step 3: Install far-infrared ceramic heating elements 4 in areas A, C1, and C2, and auxiliary heating elements 6 in areas E1 and E2. Wrap far-infrared ceramic heating ropes 7 around the connector 2. Specifically, the far-infrared ceramic heating elements 4 in areas C1 and C2 and the auxiliary heating elements 6 in areas E1 and E2 are arranged in a ring for more uniform heating. After wrapping the far-infrared ceramic heating ropes 7 around the connector 2, an additional layer of insulation material needs to be wrapped around it. Also, different heating elements are set in different areas because the connector 2 needs to be heated while other areas need auxiliary heating.

[0042] Step 4: Wrap the entire main pipe 1 with insulation material to insulate the main pipe 1. In this embodiment, the insulation material is aluminum silicate or glass wool, or other suitable insulation materials may be selected.

[0043] Step 5: Tightly wrap the inner intermediate frequency induction wire 3 around the insulation material in areas B1 and B2, and tightly wrap the outer intermediate frequency induction wire 5 around the insulation material in areas D1 and D2.

[0044] Step 6: Control the heating of the inner medium-frequency induction line 3, the far-infrared ceramic heating plate 4, the outer medium-frequency induction line 5, the auxiliary heating plate 6, and the far-infrared ceramic heating rope 7 respectively, and control the heating in zones to ensure precise control of the weld heat treatment temperature.

[0045] In this zone-controlled heat treatment method, the main pipeline 1 is divided into nine zones: A, B1, B2, C1, C2, D1, D2, E1, and E2. The main pipeline 1 is laid out and heated in zones, which not only improves the laying efficiency but also greatly reduces laying errors and improves the heat treatment effect.

[0046] The main pipe 1 and the connector 2 can be heated in zones by means of the inner medium frequency induction line 3, the far-infrared ceramic heating plate 4, the outer medium frequency induction line 5, the auxiliary heating plate 6 and the far-infrared ceramic heating rope 7. The controllability is high, which can ensure precise control of the weld heat treatment temperature.

[0047] The inner medium-frequency induction line 3 and the outer medium-frequency induction line 5 have a fast heating speed, high efficiency, and easy temperature control. They can achieve local heating while ensuring the uniformity of the main heating area. The pipe joints obtained by this heat treatment have good mechanical properties and service life.

[0048] The far-infrared ceramic heating element 4 can precisely control the heat treatment temperature of the weld, while the auxiliary heating element 6 and the far-infrared ceramic heating rope 7 can reduce heat transfer loss and ensure a uniform temperature range.

[0049] Example 2:

[0050] Please see Figures 3-5 Based on Embodiment 1, this embodiment provides a partitioning device for a method of partitioned temperature control during heat treatment of a thermal power plant header as described in Embodiment 1. It can quickly and conveniently partition the main pipeline 1. Specifically, it includes a control cabinet 8, on which eight U-shaped rods 9 are slidably arranged. The eight U-shaped rods 9 are clamped onto the main pipeline 1 from bottom to top, so that the space between each two adjacent U-shaped rods 9 is a zone, for a total of seven zones. In addition, there are the two sides of the two outermost U-shaped rods 9, for a total of nine zones, corresponding to zones A, B1, B2, C1, C2, D1, D2, E1 and E2 respectively.

[0051] By dividing the main pipeline 1 into sections using the U-shaped rod 9, different equipment can be accurately installed in each section, which not only improves the efficiency of the layout but also reduces the error rate and enhances the heat treatment effect.

[0052] like Figure 4 As shown, an adjustment mechanism is provided inside the control cabinet 8, which can adjust the position of each of the eight U-shaped rods 9 on the control cabinet 8.

[0053] Specifically, the adjustment mechanism includes a vertical shaft 10, a guide groove 11, a rotating roller 12, and a rotating shaft 13. The bottom of each of the eight U-shaped rods 9 is fixedly mounted with a vertical shaft 10. The bottom end of the vertical shaft 10 is movably disposed in the guide groove 11. The guide groove 11 is opened on the outer wall of the rotating roller 12. The rotating roller 12 is rotatably disposed in the control cabinet 8 through the rotating shaft 13. In this embodiment, the eight guide grooves 11 are divided into two groups, left and right, with the installation point of the connector seat 2 as the midpoint. Each group has four guide grooves. The left and right groups of guide grooves 11 are inclined in opposite directions on the outer wall of the rotating roller 12.

[0054] When the rotating roller 12 rotates, it can guide the vertical shaft 10 to move through the guide grooves 11 on the left and right sides, thereby enabling the four U-shaped rods 9 on the left and the four on the right to move in opposite directions, moving away from or closer to each other, to adapt to pipe seats 2 with different pipe diameters.

[0055] In this embodiment, the inclination of the four guide grooves 11 on the left and the four guide grooves 11 on the right can also be set to be different, for example, the inclination gradually increases from the inside to the outside. In this way, when the four U-shaped rods 9 on the left and the four U-shaped rods 9 on the right move in opposite directions, the distance between two adjacent U-shaped rods 9 will also change, further adapting to different pipe diameters of the pipe fitting 2: when the diameter of the pipe fitting 2 is larger, the auxiliary heating range on the main pipe 1 also needs to be larger, and more (or larger) medium frequency induction wires, far-infrared ceramic heating elements 4 and auxiliary heating elements 6 need to be installed.

[0056] In this embodiment, as Figure 5 As shown, the rotation of the rotating shaft 13 is driven by the worm gear 15. Specifically, a worm wheel 14 is fixedly installed on the rotating shaft 13, and the worm gear 15 is meshed on the outer wall of the worm wheel 14. One end of the worm gear 15 is rotatably set on the inner wall of the control cabinet 8, and the other end of the worm gear 15 extends to the outside of the control cabinet 8 and is fixedly connected to a knob 16.

[0057] Turning knob 16 causes worm 15 to rotate, which in turn drives worm wheel 14, which meshes with worm wheel 14 on its outer wall, to rotate. The rotation of worm wheel 14 drives rotating roller 12 to rotate via rotating shaft 13. Furthermore, since the transmission between worm wheel 14 and worm 15 has a self-locking characteristic, it can also prevent rotating roller 12 from reversing.

[0058] Example 3:

[0059] Please see Figures 6-8 This embodiment provides a heat source installation structure for a method of zoned temperature control during heat treatment of a thermal power plant header as described in Embodiment 1. The structure includes a steel strip 18, with grooves 19 evenly provided on both sides of the steel strip 18. A locking sleeve 24 is fixedly installed at one end of the steel strip 18. After the steel strip 18 is bent, its other end can be inserted into the locking sleeve 24 for fixation. Thus, the steel strip 18 can be wrapped around the main pipe 1 and effectively fixed, and can adapt to main pipes 1 of different diameters.

[0060] like Figure 6 and Figure 7 As shown, a retainer 17 is fixedly installed on the far-infrared ceramic heating element or auxiliary heating element. The retainer 17 is movably sleeved on the steel strip 18, so that several far-infrared ceramic heating elements 4 or auxiliary heating elements can be fixed on the steel strip 18 by the retainer 17. Then the steel strip 18 is wrapped around and fixed on the main pipe 1. In this way, the effect of uniformly installing the far-infrared ceramic heating elements 4 or auxiliary heating elements is achieved, and the installation is uniform and firm.

[0061] Specifically, such as Figure 7 As shown, both sides of the inner wall of the sleeve 17 are movably and telescopically provided with first protrusions 20 coupled to the grooves 19. The opposite sides of the two first protrusions 20 are fixedly connected with first pressure plates 21. The two first pressure plates 21 are respectively movably disposed in the two first plate cavities 22. The two first plate cavities 22 are both opened inside the sleeve 17. In addition, a first spring 23 is fixedly disposed between the first pressure plate 21 and the inner sidewall of the first plate cavity 22.

[0062] When the sleeve 17 is put on the steel strip 18, the first protrusion 20 will be locked in the groove 19 at different positions, thereby positioning the sleeve 17. When the position of the sleeve 17 needs to be adjusted, the sleeve 17 can be pushed forcefully. When the sleeve 17 is pushed forcefully, the first protrusion 20 will retract under the guidance of the groove 19 and compress the first spring 23 through the first pressure plate 21.

[0063] In practical applications, the far-infrared ceramic heating element 4 or auxiliary heating element is evenly installed on the steel strip 18 using the sleeve 17, and then the steel strip 18 is wrapped around and fixed to the main pipe 1. In this way, the far-infrared ceramic heating element 4 or auxiliary heating element can be evenly installed around the main pipe 1 and is not easy to fall off.

[0064] In this embodiment, as Figure 8As shown, a slot 25 is formed inside the locking sleeve 24. On both sides of the inner wall of the slot 25, there are second protrusions 26 coupled to the groove 19. On the opposite sides of the two second protrusions 26, there are two pressure plates 27. The two pressure plates 27 are respectively movably arranged in the two second plate cavities 28. The two second plate cavities 28 are opened inside the locking sleeve 24. In addition, a second spring 29 is fixedly arranged between the second pressure plate 27 and the inner side wall of the second plate cavity 28.

[0065] After the steel strip 18 is bent, its other end is inserted into the slot 25. The second protrusion 26 will be engaged in the groove 19 at different positions, thereby locking the position of the steel strip 18 and keeping the annular steel strip 18 at a fixed diameter. When it is necessary to adjust the diameter of the annular steel strip 18, the end of the steel strip 18 without the locking sleeve 24 can be pulled. When pulled, the second protrusion 26 will retract under the guidance of the groove 19 and compress the second spring 29 through the second pressure plate 27. Thus, it can adapt to the main pipe 1 of different diameters.

[0066] In this embodiment, as Figure 8 As shown, a nut 30 is also fixedly installed on the locking sleeve 24. A screw 31 is threadedly connected to the inner wall of the nut 30. A control button 32 is fixedly connected to one end of the screw 31 located outside the second plate cavity 28, and the other end located inside the second plate cavity 28 can abut against the second pressure plate 27.

[0067] After the end of the lead screw 31 located in the second plate cavity 28 abuts against the second pressure plate 27, the second pressure plate 27 can no longer move, and the second protrusion 26 can no longer retract. This can effectively lock the position of the steel strip 18 and prevent the diameter of the annular steel strip 18 from changing.

[0068] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A device for partitioned temperature control during heat treatment of a header of a thermal power plant, characterized in that, The power plant header includes a main pipe (1) and a connector (2), wherein the connector (2) is installed on the side wall of the main pipe (1); The main pipeline (1) is provided with multiple heating zones. The installation location of the connecting pipe seat (2) is designated as zone A. Centered on zone A, four other zones are provided, which are zone B, zone C, zone D and zone E from the inside out. Each zone is equipped with an independent heating element; Both areas A and C are equipped with far-infrared ceramic heating elements, area E is equipped with an auxiliary heating element, area B is equipped with an inner medium-frequency induction line, and area D is equipped with an outer medium-frequency induction line. Each zone is equipped with a thermocouple; Insulation material is installed between the outer wall of the main pipe and the heating element in zones B and D; It also includes auxiliary components for partitioning the main pipeline; The auxiliary component includes a control cabinet (8), on which a plurality of U-shaped rods (9) are arranged along its axial direction, and the U-shaped rods (9) are slidably connected to the control cabinet (8); The U-shaped rod (9) is clamped onto the main pipeline; the distance between two adjacent U-shaped rods (9) corresponds to the nine zones of the main pipeline; The control cabinet (8) is also equipped with an adjustment mechanism for adjusting the position of the U-shaped rod (9) in its inner cavity; The adjustment mechanism includes a vertical shaft (10), a guide groove (11), a rotating roller (12), and a rotating shaft (13). The bottom of each of the eight U-shaped rods (9) is fixedly installed with a vertical shaft (10). The bottom end of the vertical shaft (10) is movably set in the guide groove (11). The guide groove (11) is opened on the outer wall of the rotating roller (12). The rotating roller (12) is rotatably set in the control cabinet (8) through the rotating shaft (13). The eight guide grooves (11) are divided into two groups, left and right, with the installation point of the connector seat (2) as the midpoint. There are four guide grooves in each group. The guide grooves (11) of the left and right groups are opened at an angle on the outer wall of the rotating roller (12) and in opposite directions. It also includes auxiliary mounting components for assisting in the installation of the heating element.

2. The device for zoned temperature control during heat treatment of headers in thermal power plants according to claim 1, characterized in that, The auxiliary mounting component includes a steel strip (18), one end of which is fixedly fitted with a locking sleeve (24), and the other end of the steel strip (18) is bent and inserted into a slot opened on the locking sleeve (24); at the same time, a retainer (17) is fitted on the steel strip (18), and the retainer (17) is used to install the heating element.

3. A method for zoned temperature control during heat treatment of headers in thermal power plants, used in the device for zoned temperature control during heat treatment of headers in thermal power plants as described in any one of claims 1-2, characterized in that, Includes the following steps: Step 1: Divide the main pipeline (1) into zones. The installation location of the pipe fitting (2) is designated as zone A. With zone A as the center, four zones are set up, which are zone B, zone C, zone D and zone E from the inside out. Step 2: Install far-infrared ceramic heating elements in areas A and C, install auxiliary heating elements in area E, install inner medium-frequency induction wires in area B, install outer medium-frequency induction wires in area D, and install far-infrared ceramic heating ropes on the connector (2). Step 3: Control the far-infrared ceramic heating element, auxiliary heating element, inner medium-frequency induction line, outer medium-frequency induction line and far-infrared ceramic heating rope to heat the main pipe (1) in sections.

Images