Heating body of vacuum furnace

Abstract

The utility model discloses a vacuum furnace heating body which comprises a leading-in electrode section, a heating section and a series electrode section, the leading-in electrode section, the heating section and the series electrode section are integrally formed into a U shape, and steps are arranged at the joint of the heating section and the leading-in electrode section and the joint of the heating section and the series electrode section. And the sectional area of the heating section is smaller than that of the lead-in electrode section and that of the series electrode section. The heating body is integrally formed, so that the problem that the whole group of heating devices are scrapped due to the fact that the threads are burnt out due to overlarge local current at the threads, the contact surface is reduced, the threaded connection is burnt out due to overheating, and the resistance consistency of the heating area is good, and the heating area is more concentrated; and the overall stability of the heating body during working and the service life of the heating body are ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of heating elements, in particular to a heating element for a vacuum furnace. Background Art

[0002] like Figure 1 As shown, the heating element of a conventional horizontal vacuum furnace generally adopts a split design, that is, it is composed of two lead-in electrode bodies 1, two heating rods 2, and a series electrode body 3. This structure is usually connected by threads to form a whole. The two lead-in electrode bodies 1 of the heating element are respectively connected to two water-cooled electrodes, and the current forms a loop through the lead-in electrode body 1-heating rod 2-series electrode body 3-heating rod 2-lead-in electrode body 1.

[0003] There are many problems with this type of heating element:

[0004] 1. There are many processed parts, and it is difficult to control quality and size;

[0005] 2. It is difficult to ensure the consistency of resistivity. In order to ensure the consistency of resistance, sometimes the diameters of the two heating rods will be very different;

[0006] 3. The thread matching consistency is poor, the yield rate is low, and the connection thread may even become loose due to the vibration of the heating element during operation;

[0007] 4. Threaded connection is not conducive to the passage of large currents of thousands of amperes. During use, it is easy for the local current at the thread to be too large and burn the thread, resulting in a reduction in the contact surface and overheating, which causes the threaded connection to burn, thus scrapping the entire set of heating devices;

[0008] 5. The installation and replacement operations are cumbersome, resulting in long shutdown and maintenance cycles and large losses. Utility Model Content

[0009] In view of the above problems, the utility model provides a vacuum furnace heating element, which improves the reliability and stability of the heating element and also reduces the production cost and work efficiency.

[0010] Specifically, the utility model provides a vacuum furnace heating element, comprising: an introduced electrode segment, a heating segment and a series electrode segment, wherein the introduced electrode segment, the heating segment and the series electrode segment are integrally formed into a U-shape, and steps are provided at the connection between the heating segment and the introduced electrode segment and the series electrode segment, so that the cross-sectional area of ​​the heating segment is smaller than the cross-sectional area of ​​the introduced electrode segment and the series electrode segment.

[0011] Further, the introduction electrode segment comprises:

[0012] The connecting section is placed outside the vacuum furnace wall and is used to connect the water-cooled electrodes;

[0013] The extension section is located between the heating section and the connecting section. After passing through the vacuum furnace wall, it extends into the vacuum furnace. A sealing groove is provided at the connection between the extension section and the vacuum furnace wall.

[0014] Furthermore, the sealing groove comprises:

[0015] A first sealing groove is provided on the upper and lower surfaces of the extension section;

[0016] The second sealing groove is arranged on the left and right side walls of the extension section, and the first sealing groove and the second sealing groove are staggered.

[0017] Furthermore, the cross-sectional area of ​​the connecting section is larger than the cross-sectional area of ​​the extending section.

[0018] Working principle:

[0019] When the heating element is heated, a constant current forms a loop through the U-shaped heating element (introduction electrode segment 4-heating segment 5-series electrode segment 6-heating segment 5-introduction electrode segment 4) to heat the vacuum furnace. The cross-sectional area of ​​the heating segment 5 is smaller than the introduction electrode segment 4 and the series electrode segment 6 at both ends. The temperature of the area with a small heating cross-section is higher, and the temperature at both ends is lower, so that the heat generated by the heating segment 5 is greater than that at both ends, so that the heat generation is mainly concentrated in the heating segment 5 area.

[0020] Compared with the prior art, the utility model has the following beneficial effects:

[0021] (1) The heating element provided by the utility model is integrally formed, and the resistance consistency of the heating area is good, thereby ensuring the overall stability of the heating element during operation and the working life of the heating element.

[0022] (2) One-piece molding can avoid the problem of excessive local current at the thread burning the thread, resulting in a reduction in the contact area and overheating, which causes the threaded connection to burn, thereby scrapping the entire set of heating devices.

[0023] (3) One-piece molding, when replacing, you only need to take out the whole thing and replace it, without involving other parts to replace, which can effectively improve the replacement efficiency.

[0024] (4) The cross-section of the heating section is smaller than the introduction electrode section and the series electrode section at both ends, which can make the heating area more concentrated and the heat generated at both ends is smaller.

[0025] (5) The sealing groove design can make the connection between the heating element and the vacuum furnace wall more tightly combined, making it difficult for metal vapor to overflow during use, thus avoiding short circuits and arcing caused by steam overflow and condensation.

[0026] (6) The two sealing grooves are staggered to effectively prevent the problem of excessive local heating caused by a significant reduction in the cross-section of the sealing groove due to grooving. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of an existing heating element;

[0028] Figure 2 It is a schematic diagram of the structure of the heating element in Example 1;

[0029] Figure 3 is a top view of the heating element in Example 1;

[0030] Figure 4 It is a front view of the heating element in Example 1;

[0031] Figure 5 This is a schematic diagram of the usage status of the heating element in Example 1.

[0032] Reference numerals:

[0033] 1-introducing the electrode body; 2-heating rod; 3-series electrode bodies; 4-introducing the electrode segment; 41-connecting segment; 42-extension segment; 43-first sealing groove; 44-second sealing groove; 5-heating segment; 6-series electrode segment; 7-vacuum furnace; 8-water-cooled electrode. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0035] Example 1

[0036] like Figure 2-4 As shown, this embodiment provides a vacuum furnace heating element, which is formed by one-piece molding (carving removal method) of a whole graphite plate, and a semi-through groove is opened in the middle of the graphite plate. The two sides of the semi-through groove are the heating section 5 of the heating element, and the two ends are the introduction electrode section 4 and the series electrode section 6, respectively, so as to form a current path of introduction electrode section 4-heating section 5-series electrode section 6-heating section 5-introduction electrode section 4. The one-piece molding of the heating element not only ensures the consistency of the material and resistivity of the heating element, improves the overall stability and service life, but also greatly reduces the processing difficulty of the heating element.

[0037] The connection between the heating section 5 and the introduction electrode section 4 and the connection with the series electrode section 6 are both provided with steps, so that the cross-sectional area of ​​the heating section 5 is smaller than the cross-sectional area of ​​the introduction electrode section 4 and the series electrode section 6. Since the current passing through the heating element is constant, the temperature of the area with a small heating cross-sectional area is relatively high, and the temperature at both ends is relatively low. Therefore, the utility model can concentrate the heating part of the heating element in the heating section 5. The introduction electrode section 4 includes: a connecting section 41 and an extension section 42. The connecting section 41 is provided with an electrode introduction hole for connecting the water-cooled electrode 8. The extension section 42 is located between the heating section 5 and the connecting section 41. It passes through the furnace wall of the vacuum furnace 7 and then extends into the vacuum furnace 7. The cross-sectional area of ​​the connecting section 41 is larger than the cross-sectional area of ​​the extension section 42, which further reduces the heating of the connecting section 41 exposed outside the vacuum furnace 7. A first sealing groove 43 and a second sealing groove 44 are provided at the connection between the extension section 42 and the furnace wall of the vacuum furnace 7. The first sealing groove is provided on the upper and lower surfaces of the extension section 42, with two grooves on each surface; the second sealing groove is provided on the left and right side walls of the extension section 42, with two grooves on each surface. The first sealing groove 43 and the second sealing groove 44 are both used to fill sealing materials to seal the connection between the extension section 42 and the furnace wall of the vacuum furnace 7, thereby avoiding short circuit arcing caused by overflow and condensation of metal vapor.

[0038] Furthermore, the first sealing groove 43 and the second sealing groove 44 are staggered to avoid the first sealing groove 43 and the second sealing groove 44 being connected into a circle, which would cause a significant reduction in the cross-section of the sealing groove of the extension section 42, thereby causing local heating at the sealing part and affecting its service life.

[0039] The above specific examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. For those skilled in the art of the present invention, some simple deductions, deformations or substitutions can be made based on the idea of ​​the present invention.

Claims

1. A vacuum furnace heating element, comprising: introducing The electrode segment (4), the heating segment (5) and the series-connected electrode segment (6) are characterized in that the introduced electrode segment (4), the heating segment (5) and the series-connected electrode segment (6) are integrally formed into a U-shape, and steps are provided at the connection between the heating segment (5) and the introduced electrode segment (4) and the series-connected electrode segment (6), so that the cross-sectional area of ​​the heating segment (5) is smaller than the cross-sectional area of ​​the introduced electrode segment (4) and the series-connected electrode segment (6).

2. The vacuum furnace heating element according to claim 1, characterized in that: The introduction electrode segment (4) comprises: A connecting section (41) is placed outside the wall of the vacuum furnace (7) and is used to connect the water-cooled electrode (8); The extension section (42) is located between the heating section (5) and the connecting section (41), and extends into the vacuum furnace (7) after passing through the furnace wall of the vacuum furnace (7). A sealing groove is provided at the connection between the extension section (42) and the furnace wall of the vacuum furnace (7).

3. The vacuum furnace heating element according to claim 2, characterized in that: The sealing groove comprises: First sealing grooves (43) are provided on the upper and lower surfaces of the extension section (42); The second sealing groove (44) is arranged on the left and right side walls of the extension section (42), and the first sealing groove (43) and the second sealing groove (44) are arranged in a staggered manner.

4. The vacuum furnace heating element according to claim 2 or 3, characterized in that: The cross-sectional area of ​​the connecting section (41) is greater than the cross-sectional area of ​​the extending section (42).

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