Intelligent cooling rate control device for vacuum sintering furnace

Abstract

The present application belongs to the technical field of cooling rate control, in particular to an intelligent cooling rate control device for vacuum sintering furnace, which comprises a furnace body and a control cabinet, a furnace liner for sintering heating is arranged in the furnace body, furnace covers are arranged at both ends of the furnace body, sealing covers are arranged in the two furnace covers in a floating manner, an airflow driving assembly is arranged in the sealing cover, the airflow driving assembly comprises an air extraction fan blade, an exhaust hole is formed in the middle of the air extraction fan blade, the air extraction fan blade extracts the outside gas in the furnace liner through rotation to realize the circulation of the inner and outer layers of the gas flow in the furnace liner during the cooling process, and the pressure difference between the two sides of the air extraction fan blade gives the sealing cover an extrusion force to the furnace liner, a detection assembly for detecting the temperature in the furnace liner is arranged outside the furnace body, and the airflow driving assembly and the detection assembly are electrically connected with the control cabinet; through the cooperation of the above structure, the flow of the inner and outer layers of the inert gas in the furnace liner is realized during the cooling process of the sintering furnace, and the uneven cooling rate phenomenon caused by the edge effect is avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cooling rate control, in particular to a vacuum sintering furnace intelligent cooling rate control device. BACKGROUND

[0002] The vacuum sintering furnace is a kind of equipment for high-temperature sintering of material powder in a vacuum environment, which removes oxygen and impurity gas by vacuum pumping, and then heats to a preset temperature to make powder particles bond and diffuse to form a dense block material, thereby improving its performance and purity. After the material is completed vacuum sintering, the control of the cooling rate is crucial to the final performance of the material formed by sintering (such as grain size, stress state, phase composition, etc.). The existing vacuum sintering furnace usually adopts a combination of inert gas convection, cooling medium conduction and radiation shielding adjustment, and a temperature closed-loop feedback program control to achieve a wide range of cooling rate regulation from 0.1℃ / min (slow) to 50℃ / min (fast).

[0003] However, the above-mentioned technology often has the following defects: for some large vacuum sintering furnaces (furnace diameter > 1m), due to the influence of gas density difference (low-temperature gas sinking), the gas flow rate at the bottom of the furnace is 20%-30% higher than that at the top as the temperature decreases, resulting in a cooling rate difference of more than 10℃ / min between the upper and lower areas. At the same time, due to the edge effect of heat dissipation, the cooling rate of the inner and outer layers of the inert gas in the inner shell of the sintering furnace appears to be different, thereby making it difficult to ensure the spatial uniformity of the cooling rate. In addition, due to the difference in cooling rate, the deformation of each part of the sintering furnace is uncontrollable, thereby affecting the sealing performance of the sintering furnace.

[0004] Therefore, the present application provides a vacuum sintering furnace intelligent cooling rate control device. SUMMARY

[0005] In order to make up for the deficiencies of the prior art and solve at least one technical problem raised in the background art.

[0006] The technical scheme adopted by the present application to solve its technical problems is: the vacuum sintering furnace intelligent cooling rate control device according to the present application comprises a furnace body and a control cabinet, a furnace shell for sintering and heating is arranged in the furnace body, furnace covers are arranged at both ends of the furnace body, sealing covers are floatingly arranged in the two furnace covers, an airflow driving assembly is arranged in the sealing cover, the airflow driving assembly comprises exhaust fan blades, exhaust holes are formed in the middle of the exhaust fan blades, the exhaust fan blades extract the outside gas in the furnace shell by rotating to realize the circulation of the airflow in and outside the furnace shell during the cooling process, the pressure difference between the two sides of the exhaust fan blades gives the sealing cover an extrusion force to the furnace shell, a detection assembly for detecting the temperature in the furnace shell is arranged outside the furnace body, and the airflow driving assembly and the detection assembly are electrically connected with the control cabinet.

[0007] Further, the sealing cover is composed of a fixed seat, an elastic support and a ring-shaped pressing sleeve, the fixed seat is fixed in the furnace cover, and the ring-shaped pressing sleeve is arranged outside the fixed seat and used for abutting against the end face of the furnace body; the elastic support is arranged between the fixed seat and the ring-shaped pressing sleeve.

[0008] Further, the elastic support comprises pre-tightening springs and thermal expansion compensation springs which are uniformly distributed along the circumference of the fixed seat and are arranged at intervals.

[0009] Further, the sealing surface of the ring-shaped pressing sleeve is coated with a diamond-like coating layer, the thickness of the coating layer is 3-5 microns, and the friction coefficient is less than or equal to 0.1.

[0010] Further, a flexible graphite transition layer is arranged at the contact position of the diamond-like coating layer and the furnace body, and the thickness of the flexible graphite transition layer is 0.2-0.4 mm.

[0011] Further, the airflow driving assembly further comprises a transmission column for radially fixing the air extraction fan blades, one end of the transmission column is provided with a linkage bracket part connected with the air extraction fan blades, one end of the transmission column is arranged outside the sealing cover and is provided with a driven gear, a transmission shaft is arranged outside the furnace cover, and the outer side of the transmission shaft is provided with a driving gear matched with the driven gear, and a driving motor is arranged outside the furnace cover and used for driving the transmission shaft.

[0012] Further, the detection assembly comprises thermocouples and a pressure sensor, the thermocouples are arranged outside the furnace body in an axial symmetry mode, and the pressure sensor is arranged on the inner wall of the furnace body.

[0013] Further, the control cabinet is provided with a control module based on an LSTM neural network, and the control module is electrically connected with the thermocouples, the pressure sensor and the airflow driving assembly.

[0014] The beneficial effects of the present application are as follows:

[0015] 1. The vacuum sintering furnace intelligent cooling rate control device can detect the temperature in the furnace body through the detection assembly, drive the inert gas in the furnace body as a heat transfer medium through the air extraction fan blades, make the inner and outer layers of the gas in the furnace body flow in a circulating mode, avoid the edge effect and the gas cooling sinking phenomenon in the cooling process, and control the spatial uniformity of the cooling rate.

[0016] 2. The intelligent cooling rate control device for vacuum sintering furnace described in this invention adopts a floating design for the sealing covers used to seal both ends of the furnace liner, which enables the sealing cover to be automatically adjusted according to the actual expansion deformation, thereby improving the sealing performance at both ends of the furnace liner. At the same time, the pressure difference on both sides of the exhaust fan blades provides the sealing cover with a squeezing force against the furnace liner, avoiding the phenomenon that static seals are prone to failure under airflow disturbance, and further improving the fit between the sealing cover and the end face of the furnace liner. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1 This is a perspective view of the present invention;

[0019] Figure 2 This is the front view of the present invention;

[0020] Figure 3 yes Figure 2 Sectional view at point AA;

[0021] Figure 4 yes Figure 3 Enlarged view of a section at point B in the middle;

[0022] Figure 5 This is a three-dimensional view of one side of the furnace cover portion in this invention;

[0023] Figure 6 This is a three-dimensional view of one side of the furnace cover portion in this invention;

[0024] Figure 7 This is a three-dimensional schematic diagram of the transmission column in this invention.

[0025] In the diagram: 1. Furnace body; 2. Control cabinet; 3. Furnace liner; 4. Furnace cover; 5. Sealing cover; 6. Airflow drive assembly; 7. Detection assembly; 8. Diamond-like carbon coating; 9. Flexible graphite transition layer; 10. Control module; 50. Fixing base; 51. Elastic support; 52. Ring-shaped pressure sleeve; 60. Exhaust fan blade; 61. Transmission column; 62. Driven gear; 63. Transmission shaft; 64. Drive gear; 65. Drive motor; 70. Thermocouple; 71. Pressure sensor; 510. Preload spring; 511. Thermal expansion compensation spring. Detailed Implementation

[0026] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0027] Example 1: As Figures 1 to 7 As shown in the embodiment of the present invention, the intelligent cooling rate control device for the vacuum sintering furnace is described.

[0028] likeFigure 1 、 Figure 2 and Figure 3 As shown in FIGS. 1, 2 and 3, the sintering furnace comprises a furnace body 1 and a control cabinet 2, the furnace body 1 is provided with a furnace barrel 3 for sintering heating, both ends of the furnace body 1 are provided with furnace covers 4, and the two furnace covers 4 are floatingly provided with sealing covers 5, the sealing cover 5 is composed of a fixed seat 50, an elastic support 51 and a ring-shaped pressing sleeve 52, the fixed seat 50 is fixedly arranged in the furnace cover 4, an outer portion of the fixed seat 50 is sleeved with the ring-shaped pressing sleeve 52 for abutting with the end face of the furnace barrel 3, and the elastic support 51 is arranged between the fixed seat 50 and the ring-shaped pressing sleeve 52, the variable elastic support 51 can absorb the thermal expansion difference between different components, and the position of the ring-shaped pressing sleeve 52 can be automatically adjusted according to the actual expansion deformation of the furnace barrel 3, so that the sealing performance of both ends of the furnace barrel 3 is improved.

[0029] As shown in FIGS. 4, 5 and 6, it is found that the elastic modulus of the spring decreases in the high-temperature environment during the working process, especially when the temperature in the furnace reaches 1000-1600℃, so the elastic support 51 is designed to be composed of pre-tightening springs 510 and thermal expansion compensation springs 511 which are uniformly distributed along the circumference of the fixed seat 50, and the pre-tightening springs 510 and the thermal expansion compensation springs 511 are arranged at intervals, so that the pre-tightening springs 510 provide stable initial pressing force for the ring-shaped pressing sleeve 52 in the normal temperature static state or low-temperature working state, the ring-shaped pressing sleeve 52 is tightly abutted with the end port of the furnace barrel 3, and the initial leakage caused by assembly gap or gravity is avoided, when the temperature of the sintering furnace is high, the elastic deformation of the thermal expansion compensation spring 511 can absorb the thermal expansion difference of different components, that is, when the furnace barrel 3 expands due to high temperature, the thermal expansion compensation spring 511 is compressed, and the ring-shaped pressing sleeve 52 is pushed to abut the furnace barrel 3 synchronously through the elastic force; when the temperature decreases and shrinks, the thermal expansion compensation spring 511 rebounds to maintain the sealing pressure, and the stability of the contact stress of the sealing surface in the whole temperature range is ensured. Figure 6 As shown in FIGS. 7, 8 and 9, in the actual use process, the ring-shaped pressing sleeve 52 and the end face of the furnace barrel 3 are frequently rubbed and worn due to frequent opening and closing of the furnace cover in the vacuum sintering furnace, which has a bad influence on the sealing performance and service life of the ring-shaped pressing sleeve 52, so a diamond-like carbon coating 8 is plated on the sealing surface of the ring-shaped pressing sleeve 52, the thickness of the coating is 3-5μm, and the friction coefficient is ≤0.1.

[0030] Figure 3 As shown in FIGS. 10, 11 and 12, in the actual use process, it is also found that the end face of the furnace barrel 3 is also worn, so a flexible graphite transition layer 9 is arranged at the contact position between the diamond-like carbon coating 8 and the furnace barrel 3, the thickness of the flexible graphite transition layer 9 is 0.2-0.4mm, and the transition lubricating effect is realized through the flexible graphite transition layer 9. Figure 4 As shown in FIGS. 13, 14 and 15, in the actual use process, it is also found that the end face of the furnace barrel 3 is also worn, so a flexible graphite transition layer 9 is arranged at the contact position between the diamond-like carbon coating 8 and the furnace barrel 3, the thickness of the flexible graphite transition layer 9 is 0.2-0.4mm, and the transition lubricating effect is realized through the flexible graphite transition layer 9.

[0031] Figure 3 As shown in FIGS. 16, 17 and 18, in the actual use process, it is also found that the end face of the furnace barrel 3 is also worn, so a flexible graphite transition layer 9 is arranged at the contact position between the diamond-like carbon coating 8 and the furnace barrel 3, the thickness of the flexible graphite transition layer 9 is 0.2-0.4mm, and the transition lubricating effect is realized through the flexible graphite transition layer 9. Figure 4 As shown in FIGS. 19, 20 and 21, in the actual use process, it is also found that the end face of the furnace barrel 3 is also worn, so a flexible graphite transition layer 9 is arranged at the contact position between the diamond-like carbon coating 8 and the furnace barrel 3, the thickness of the flexible graphite transition layer 9 is 0.2-0.4mm, and the transition lubricating effect is realized through the flexible graphite transition layer 9.

[0032] As​​Figure 5 As shown, the sealing cover 5 is provided with an airflow driving assembly 6, the airflow driving assembly 6 includes an air extraction fan blade 60, the air extraction fan blade 60 is provided with an exhaust hole in the middle part, and further includes a transmission column 61 for radially fixing the air extraction fan blade 60, one end of the transmission column 61 is provided with a linkage bracket part connected with the air extraction fan blade 60, and the other end of the transmission column 61 is externally sleeved with a driven gear 62 after penetrating through the sealing cover 5, the outer side of the furnace cover 4 is provided with a transmission shaft 63, and the outer side of the transmission shaft 63 is provided with a driving gear 64 matched with the driven gear 62, and the outer side of the furnace cover 4 is provided with a driving motor 65 driving the transmission shaft 63, the transmission shaft 63 is driven to rotate by the driving motor 65 with the driving gear 64, and the synchronous rotation of the driven gear 62 is realized through the meshing transmission between the driving gear 64 and the driven gear 62, so that the linkage bracket part of the transmission column 61 drives the air extraction fan blade 60 to rotate, realizes the extraction of the outer layer of the inert gas in the furnace barrel 3, and makes the extracted gas bypass the air extraction fan blade 60 and then discharge from the exhaust hole in the middle part, finally realizes the circulation flow of the inner and outer layers of the gas in the furnace barrel 3 during the cooling process, and the pressure difference between the two sides of the air extraction fan blade 60 gives the extrusion force of the ring-shaped pressure sleeve 52 to the furnace barrel 3.

[0033] As shown in the figure, Figure 1 The furnace body 1 is provided with a detection assembly 7 for detecting the temperature in the furnace barrel 3, and the airflow driving assembly 6 and the detection assembly 7 are electrically connected with the control cabinet 2, so that the actual situation in the furnace barrel 3 can be detected in real time through the detection assembly 7, and the rotation speed of the driving motor 65 in the flow driving assembly 6 is adjusted in real time according to the detection result, and the flow rate of the circulation flow of the inner and outer layers of the gas in the furnace barrel 3 is adjusted, so that the uniformity of the cooling rate space in the vacuum sintering furnace can be controlled.

[0034] Example two: as shown in the figure, Figures 1 to 3 Another embodiment of the present application is:

[0035] In the implementation, due to the non-linear change of the temperature when the vacuum sintering furnace cools down, there is a problem of response lag in detection and adjustment, so the detection assembly 7 is designed to include thermocouples 70 and a pressure sensor 71. Several thermocouples 70 are symmetrically arranged along the axis outside the furnace body 1, and the pressure sensor 71 is installed on the inner wall of the furnace barrel 3. A control module 10 based on an LSTM neural network is built in the control cabinet 2, and the control module 10 is electrically connected with the thermocouples 70, the pressure sensor 71 and the airflow driving assembly 6 respectively. The axial temperature gradient data in the furnace barrel 3 is collected in real time by the thermocouples 70 and the pressure sensor 71 (the sampling frequency is ≥10Hz), and a temperature field space-time distribution model is constructed. When the temperature difference between the upper and lower regions is identified to be >5℃, the speed regulation of the driving motor 65 is triggered immediately, the speed of the exhaust fan blade 60 is increased, and the temperature stratification is quickly eliminated by increasing the airflow circulation intensity. When the temperature difference is reduced to ≤3℃, the speed of the driving motor 65 is automatically adjusted to the reference value, avoiding energy waste caused by excessive adjustment.

[0036] Working principle: Before work, the control module 10 collects historical process data to build a model, so as to master the temperature gradient and fan speed mapping relationship under different working conditions.

[0037] During the cooling process, the variability of the elastic support 51 can absorb the thermal expansion difference between different parts, and then automatically adjust the position of the ring type pressure sleeve 52 according to the actual expansion deformation of the furnace barrel 3, so that the sealing performance of the two ends of the furnace barrel 3 is improved. The axial temperature gradient data in the furnace barrel 3 is collected in real time by the thermocouples 70 and the pressure sensor 71 (the sampling frequency is ≥10Hz), and a temperature field space-time distribution model is constructed. When the temperature difference between the upper and lower regions is identified to be >5℃, the speed regulation of the driving motor 65 is triggered immediately, the speed of the exhaust fan blade 60 is increased, and the temperature stratification is quickly eliminated by increasing the airflow circulation intensity. When the temperature difference is reduced to ≤3℃, the speed of the driving motor 65 is automatically adjusted to the reference value, avoiding energy waste caused by excessive adjustment, and at the same time, the pressure difference on both sides of the exhaust fan blade 60 gives the extrusion force of the ring type pressure sleeve 52 to the furnace barrel 3.

[0038] The above front, rear, left, right, up and down are based on the drawings in the specification Figure 1 As the standard of the human observation angle, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0039] In the description of the application, it is to be understood that the terms "center", "longitudinal", "transverse", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are used only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the application.

[0040] The basic principles, main features and advantages of the application are shown and described above. Those skilled in the art should understand that the application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the application. Without departing from the spirit and scope of the application, various changes and improvements can be made to the application, and these changes and improvements all fall within the scope of the application. The scope of protection of the application is defined by the appended claims and their equivalents.

Claims

1. A smart cooling rate control device for a vacuum sintering furnace, comprising a furnace body (1) and a control cabinet (2), characterized in that: The furnace body (1) is provided with a furnace liner (3) for sintering heating. Both ends of the furnace body (1) are provided with furnace covers (4). A sealing cover (5) is floating inside the two furnace covers (4). An airflow drive assembly (6) is provided inside the sealing cover (5). The airflow drive assembly (6) includes an exhaust fan (60). An exhaust vent is opened in the middle of the exhaust fan (60). The exhaust fan (60) extracts the outer gas inside the furnace liner (3) by rotating, so as to realize the circulation of airflow between the inner and outer layers of the furnace liner (3) during the cooling process. The pressure difference on both sides of the exhaust fan (60) gives the sealing cover (5) a squeezing force to the furnace liner (3). A detection assembly (7) for detecting the temperature inside the furnace liner (3) is provided outside the furnace body (1). Both the airflow drive assembly (6) and the detection assembly (7) are electrically connected to the control cabinet (2). The sealing cover (5) is composed of a fixed seat (50), an elastic support (51) and an annular pressure sleeve (52). The fixed seat (50) is fixed inside the furnace cover (4), and the annular pressure sleeve (52) for fitting with the end face of the furnace liner (3) is sleeved on the outside of the fixed seat (50). An elastic support (51) is provided between the fixed seat (50) and the annular pressure sleeve (52).

2. The intelligent cooling rate control device for vacuum sintering furnace according to claim 1, characterized in that: The elastic support (51) includes a preload spring (510) and a thermal expansion compensation spring (511) evenly distributed around the fixed base (50), and the preload spring (510) and the thermal expansion compensation spring (511) are spaced apart.

3. The intelligent cooling rate control device for a vacuum sintering furnace according to claim 2, characterized in that: The sealing surface of the annular pressure sleeve (52) is coated with a diamond-like coating (8), the coating thickness is 3-5μm, and the coefficient of friction is ≤0.

1.

4. The intelligent cooling rate control device for vacuum sintering furnace according to claim 3, characterized in that: The contact area between the diamond-like coating (8) and the furnace lining (3) is provided with a flexible graphite transition layer (9) with a thickness of 0.2-0.4 mm.

5. The intelligent cooling rate control device for a vacuum sintering furnace according to claim 1, characterized in that: The airflow drive assembly (6) also includes a drive column (61) for radially fixing the exhaust fan blade (60). One end of the drive column (61) is provided with a linkage bracket part connected to the exhaust fan blade (60). One end of the drive column (61) passes through the sealing cover (5) and is fitted with a driven gear (62). A drive shaft (63) is provided through the outer side of the furnace cover (4), and a drive gear (64) matching the driven gear (62) is provided on the outer side of the drive shaft (63). A drive motor (65) for driving the drive shaft (63) is provided on the outer side of the furnace cover (4).

6. The intelligent cooling rate control device for a vacuum sintering furnace according to claim 1, characterized in that: The detection component (7) includes thermocouples (70) and pressure sensors (71). Several thermocouples (70) are symmetrically arranged along the axial direction outside the furnace body (1), and the pressure sensors (71) are installed on the inner wall of the furnace shell (3).

7. The intelligent cooling rate control device for a vacuum sintering furnace according to claim 6, characterized in that: The control cabinet (2) has a built-in control module (10) based on LSTM neural network, and the control module (10) is electrically connected to the thermocouple (70), the pressure sensor (71) and the airflow drive assembly (6).

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