Miniature visual electric heating furnace

Abstract

The utility model discloses a miniature visual electrothermal furnace, which comprises a furnace body assembly, a furnace plate assembly and a furnace cover assembly, the furnace body assembly comprises a furnace shell and a glass assembly, a furnace cavity is arranged in the furnace shell, at least one layer of heat insulation grid is arranged between the furnace plate assembly and the furnace shell, and a first electrode and a thermocouple joint are embedded in the side wall of the furnace shell. The thermocouple joint penetrates through the heat insulation grid and then abuts against the furnace plate assembly in a matched mode. The furnace plate assembly comprises a furnace plate, a first ceramic spraying layer, a nickel-chromium electric heating sheet and a second ceramic spraying layer, a sample plate is arranged in the furnace plate, and the first ceramic spraying layer, the nickel-chromium electric heating sheet and the second ceramic spraying layer are provided with through grooves corresponding to the sample plate; the furnace cover assembly comprises a furnace body sealing cover and a sealing cover frame, and the furnace body sealing cover and the furnace shell are fixed in a matched mode through a fastener. The vacuumizing device connected with the gas inlet pipe joint and the gas outlet pipe joint is used for vacuumizing the interior of the furnace chamber, and the heat transfer medium is reduced by arranging the multiple layers of heat insulation grids, so that the heating temperature of a sample is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric heating stoves, and in particular relates to a miniature visual electric heating stove. Background Art

[0002] Laser flash method (LFM) is a transient method for measuring the thermal diffusivity of materials. Laser thermal conductivity meters based on the principle of laser flash method are widely used in the characterization of thermal properties of materials such as ceramics and metals. The standard structure of the laser flash method test device is a light source, a temperature-controlled sample chamber, and a detector from bottom to top. In actual use, due to the small distance between the detector and the light source, the small thickness of the sample chamber and the light transmission from top to bottom, the thermal insulation performance of the sample chamber is poor, and the controllable temperature in the chamber is generally difficult to exceed 300°C.

[0003] The present invention proposes a micro-transmitting photothermal furnace suitable for the laser flash method. The furnace body can provide an atmosphere protection environment ranging from room temperature to 500° C., which can effectively improve the temperature measurement range and accuracy compatible with the device. Utility Model Content

[0004] In order to make up for the deficiencies of the prior art, the utility model provides a miniature visual electric heating furnace that provides an environment ranging from room temperature to 500° C., so as to solve the problem that the temperature of the existing sample bin is too low.

[0005] The miniature visual electric heating stove comprises a stove body assembly, a stove plate assembly and a stove cover assembly, wherein the stove body assembly comprises a stove shell, the bottom wall of the stove shell is provided with a glass assembly corresponding to the stove plate assembly, a stove cavity is provided in the stove shell, the stove plate assembly is placed in the middle of the stove cavity, at least one layer of heat insulation grid is provided between the stove plate assembly and the stove shell, a first electrode and a thermocouple joint are embedded in the side wall of the stove shell, and the thermocouple joint passes through the heat insulation grid and abuts against the stove plate assembly;

[0006] The furnace plate assembly includes a furnace plate, a first ceramic spray layer, a nickel-chromium electric heater and a second ceramic spray layer in order from top to bottom. A sample plate is arranged in the furnace plate. The first ceramic spray layer, the nickel-chromium electric heater and the second ceramic spray layer are all provided with through grooves corresponding to the sample plate. A second electrode is arranged on the nickel-chromium electric heater and is connected to the first electrode through a wire.

[0007] The furnace cover assembly includes a furnace body cover and a cover frame, the furnace body cover is fixed to the furnace shell by fasteners; the cover frame is embedded in the middle of the furnace body cover, corresponding to the furnace plate, and the cover frame is provided with a glass window corresponding to the sample plate.

[0008] Furthermore, the furnace plate assembly is fixed to the bottom wall of the furnace shell by means of a column pin arranged at the bottom; the top of the column pin is arranged to be an inverted cone structure, which is plugged and matched with a positioning hole arranged on the furnace plate assembly.

[0009] Furthermore, an air inlet pipe joint and an air outlet pipe joint are also provided on the side wall of the furnace shell.

[0010] Furthermore, an upper glass baffle is arranged below the cover frame, and the upper glass baffle is arranged above the furnace plate assembly and corresponds to the position of the furnace shell; the upper glass baffle is fixed to the bottom of the cover frame through a connecting column.

[0011] Furthermore, the furnace body cover is provided with a water cooling groove around the cover frame, and the water cooling groove is equipped with a water cooling pipe for circulating cooling.

[0012] Furthermore, a cross-shaped through groove is provided in the middle of the sample tray to place the sample while avoiding blocking light and infrared detection.

[0013] Furthermore, the first ceramic spray layer is made of a composite ceramic spray layer of aluminum oxide and zirconium oxide; the nickel-chromium heating plate and the second ceramic spray layer are made of aluminum oxide ceramic spray layer.

[0014] Furthermore, the glass assembly includes a lower glass baffle and a pressure plate, the bottom wall of the furnace shell is provided with a through opening, a clamping platform is provided at the lower interface of the through opening, the lower glass baffle is clamped and matched with the clamping platform, and is fixed by the pressure plate.

[0015] Compared with the prior art, the utility model has the following advantages:

[0016] (1) Different from the traditional method of straight-out heating wire, in order to facilitate the maintenance and replacement of the heating plate, the present application adopts nickel-chromium alloy sheet (i.e. nickel-chromium electric heating sheet) for heating, and the built-in second electrode is softly connected to the first electrode on the side wall (i.e. connected by a wire, and the outside of the wire needs to be covered with an asbestos sheath for protection). In this way, the heating plate can be stored separately to prevent it from getting wet when not used for a long time, and it can also be dried externally to reduce the risk of short circuit or fuse; the heating plate is more flexible, safer, and easy to install and maintain.

[0017] (2) Different from the traditional heating wire coiling method, the furnace plate of the present application is provided with four sample plates, and a large cross-shaped light-transmitting hole is set in the sample plate. Conventional coiling and insulation methods cannot be used. Therefore, the present application adopts a multi-layer composite ceramic spraying method to fix and insulate the heating wire.

[0018] (3) Unlike traditional insulation materials such as asbestos and alumina ceramics that are prone to chipping and damage, in order to achieve cleanliness inside the sample chamber and the gas path, this application designs a multi-layer insulation grid (using stainless steel sheets) for insulation and heat preservation. It can not only effectively reduce convective heat transfer and radiant heat absorption, ensuring that the temperature inside the sample chamber can reach 500 degrees; it can also greatly reduce its own weight, is not easy to damage and does not require maintenance.

[0019] (4) Unlike the traditional method of fixing the furnace plate and base with screws, the furnace body of the present application is provided with four pins (the top of the pins is designed to be an inverted cone) at the bottom of the furnace body, which are fixed in line contact with the positioning holes of the furnace plate assembly, greatly reducing the heat transfer area and making the furnace shell temperature lower; the heat-insulating furnace shell does not require maintenance, has a longer service life, and the surface temperature of the furnace shell is low.

[0020] (5) Different from the traditional external water cooling environment, the furnace cover of the present application is cooled by circulating water at normal temperature by pressing the water cooling pipe into the water cooling groove, which improves the cooling efficiency through targeted cooling, effectively reduces the working environment temperature of the external detector, and improves its accuracy and life; the upper detector can be better protected by circulating water through the furnace cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the utility model;

[0022] Figure 2 This is a bottom structure diagram of the utility model;

[0023] Figure 3 This is the top structural diagram of the utility model;

[0024] Figure 4 For this utility model Figure 3 Sectional view at AA;

[0025] Figure 5 For this utility model Figure 3 Sectional view at the middle BB;

[0026] Figure 6 This is a schematic diagram of the structure of the furnace plate assembly of the utility model.

[0027] Among the figure: 10-furnace body assembly, 11-furnace shell, 12-furnace chamber, 13-glass assembly, 131-lower glass baffle, 132-pressing plate, 20-furnace plate assembly, 21-furnace plate, 22-first ceramic spray coating, 23-nickel-chromium electric heating sheet, 24-second ceramic spray coating, 25-sample tray, 26-second electrode, 30-furnace cover assembly, 31-furnace body cover, 311-water cooling tank, 32-covering frame, 33-glass window, 34-upper glass baffle, 35-connecting column, 40-insulation grid, 50-first electrode, 60-thermocouple joint, 70-column pin, 80-inlet pipe joint, 90-outlet pipe joint. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the present invention is further described below in conjunction with the accompanying drawings.

[0029] like Figure 1-Figure 5As shown, a miniature visual electric heating stove comprises a stove body assembly 10, a stove plate assembly 20 and a stove cover assembly 30. The stove body assembly 10 comprises a stove shell 11. The bottom wall of the stove shell 11 is provided with a glass assembly 13 corresponding to the stove plate assembly 20. A stove cavity 12 is provided in the stove shell 11. The stove plate assembly 20 is placed in the middle of the stove cavity 12. At least one layer of heat insulation grid 40 is provided between the stove plate assembly 20 and the stove shell 11. A first electrode 50 and a thermocouple joint 60 are embedded in the side wall of the stove shell 11. The thermocouple joint 60 passes through the heat insulation grid 40 and abuts against the stove plate assembly 20. The stove plate assembly 20 is fixed with the bottom wall of the stove shell 11 by a column pin 70 provided at the bottom; the top of the column pin 70 is provided with an inverted cone structure, which is plugged and matched with the positioning hole provided on the stove plate assembly 20. The side wall of the stove shell 11 is also provided with an air inlet pipe joint 80 and an air outlet pipe joint 90 (the positions of the air inlet pipe joint 80 and the air outlet pipe joint 90 can be replaced). The glass assembly 13 includes a lower glass baffle 131 and a pressure plate 132. A through opening 111 is provided on the bottom wall of the furnace shell 11. A card table is provided at the lower interface of the through opening 111. The lower glass baffle 131 is engaged with the card table and fixed by the pressure plate 132; wherein the pressure plate 132 is fixed to the bottom wall of the furnace shell 11 by fasteners. In the present application, the fasteners are preferably bolts or screws and other components for fixing. It can be understood that the present application can effectively reduce convective heat transfer and radiation heat absorption by providing a multi-layer heat insulation grid (using stainless steel sheets) for heat insulation, ensuring that the temperature in the sample chamber can reach 500 degrees, and greatly reducing the dead weight, not easy to damage and requiring no maintenance.

[0030] like Figure 6 As shown, the furnace plate assembly 20 includes a furnace plate 21, a first ceramic spray layer 22, a nickel-chromium electric heater 23 and a second ceramic spray layer 24 from top to bottom. A sample plate 25 is arranged in the furnace plate 21. The first ceramic spray layer 22, the nickel-chromium electric heater 23 and the second ceramic spray layer 24 are provided with through grooves corresponding to the sample plate 25. A cross-shaped through groove is arranged in the middle of the sample plate 25 to avoid blocking light and infrared detection while placing the sample. The first ceramic spray layer 22 adopts a composite ceramic spray layer of aluminum oxide and zirconium oxide. Because zirconium oxide is heat-insulating but easy to conduct electricity at high temperature, aluminum oxide is mixed for insulation; the nickel-chromium electric heater 23 and the second ceramic spray layer 24 adopt aluminum oxide ceramic spray layer, because the lower ceramic spray layer only needs insulation. As can be seen from the figure, in this application, four sample plates 25 are arranged in the furnace plate 21. Since the cross-shaped through groove in the middle of the sample plate 25 cannot be wound and insulated in a conventional manner, the nickel-chromium electric heater 23 is fixed and insulated by a multi-layer composite ceramic spraying method. A nickel-chromium alloy sheet (i.e., nickel-chromium electric heating sheet 23) is used for heating, so that it is convenient for later maintenance and replacement.

[0031] In addition, a second electrode 26 is provided on the nickel-chromium heating plate 23, and the second electrode 26 is connected to the first electrode 50 on the side wall through a wire, and the outer part of the wire needs to be covered with an asbestos sheath for protection. Therefore, the nickel-chromium heating plate 23 can be stored separately to prevent moisture from being absorbed by the nickel-chromium heating plate 23 when not in use for a long time, and can also be dried externally to reduce the risk of short circuit or fuse. The nickel-chromium heating plate 23 has greater flexibility, better safety, and is easy to install and maintain.

[0032] The furnace cover assembly 30 includes a furnace cover 31 and a cover frame 32. The furnace cover 31 is fixed to the furnace shell 11 by fasteners. The cover frame 32 is embedded in the middle of the furnace cover 31 and is arranged corresponding to the furnace plate 21. The cover frame 32 is provided with a glass window 33 corresponding to the sample plate 25. An upper glass baffle 34 is also arranged below the cover frame 32. The upper glass baffle 34 is arranged above the furnace plate assembly 20 and corresponds to the position of the furnace shell 11. The upper glass baffle 34 is fixed to the bottom of the cover frame 32 through a connecting column 35. The furnace cover 31 is provided with a water cooling groove 311 around the cover frame 32. The water cooling pipe is installed in the water cooling groove 311, and circulating water is passed into the water cooling groove 311, which can effectively reduce the working environment temperature of the external detector and improve its accuracy and life.

[0033] When the present application is in use, the furnace cover assembly 30 is opened to place the sample on the sample tray 25, the furnace cover assembly 30 is closed, and the electric heating furnace is moved to the working position; a start signal is given (i.e., the solenoid valve is opened to open the pipeline, which is an operation step known to those skilled in the art), and a vacuum pump or a gas charging device (not shown in the figure) connected to the air inlet pipe joint 80 and the air outlet pipe joint 90 is used to evacuate or pass protective gas; the solenoid valve is closed to close the pipeline; the temperature is raised to the set temperature and then kept warm until the temperature is stable; after the experiment is completed, protective gas is passed in to quickly cool down, and after the temperature drops to a safe range, the furnace cover assembly 30 is opened to replace the sample. The present application uses a vacuum pump connected to the air inlet pipe joint 80 and the air outlet pipe joint 90 to evacuate the furnace chamber 12, and sets a multi-layer heat insulation grid 40 to reduce the heat transfer medium to ensure the heating temperature of the sample; protective gas is passed in through the gas charging device connected to the air inlet pipe joint 80 and the air outlet pipe joint 90 to quickly and evenly cool down.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present invention.

Claims

1. A miniature visual electric heating stove, comprising a stove body assembly (10), a stove plate assembly (20) and a stove cover assembly (30), characterized in that: The furnace body assembly (10) comprises a furnace shell (11); a glass assembly (13) is provided on the bottom wall of the furnace shell (11) corresponding to the furnace plate assembly (20); a furnace cavity (12) is provided in the furnace shell (11); the furnace plate assembly (20) is placed in the middle of the furnace cavity (12); at least one layer of heat insulation grid (40) is provided between the furnace plate assembly (20) and the furnace shell (11); a first electrode (50) and a thermocouple joint (60) are embedded in the side wall of the furnace shell (11); the thermocouple joint (60) passes through the heat insulation grid (40) and then abuts against the furnace plate assembly (20); The furnace plate assembly (20) comprises, from top to bottom, a furnace plate (21), a first ceramic spray layer (22), a nickel-chromium electric heating plate (23) and a second ceramic spray layer (24); a sample plate (25) is arranged in the furnace plate (21); the first ceramic spray layer (22), the nickel-chromium electric heating plate (23) and the second ceramic spray layer (24) are all provided with through grooves corresponding to the sample plate (25); a second electrode (26) is arranged on the nickel-chromium electric heating plate (23) and is connected to the first electrode (50) via a wire; The furnace cover assembly (30) comprises a furnace body cover (31) and a cover frame (32), wherein the furnace body cover (31) is fixed to the furnace shell (11) by means of fasteners; the cover frame (32) is embedded in the middle of the furnace body cover (31) and is arranged corresponding to the furnace plate (21), and the cover frame (32) is provided with a glass window (33) corresponding to the sample plate (25).

2. A miniature visual electric heating stove according to claim 1, characterized in that: The furnace plate assembly (20) is fixed to the bottom wall of the furnace shell (11) by means of a column pin (70) arranged at the bottom; the top of the column pin (70) is arranged in an inverted cone structure, which is plugged into a positioning hole arranged on the furnace plate assembly (20).

3. A miniature visual electric heating stove according to claim 1 or 2, characterized in that: The side wall of the furnace shell (11) is also provided with an air inlet pipe joint (80) and an air outlet pipe joint (90).

4. The miniature visual electric heating stove according to claim 1, characterized in that: An upper glass baffle (34) is also provided below the cover frame (32); the upper glass baffle (34) is mounted above the furnace plate assembly (20) and corresponds to the position of the furnace shell (11); the upper glass baffle (34) is fixed to the bottom of the cover frame (32) via a connecting column (35).

5. A miniature visual electric heating stove according to claim 1 or 4, characterized in that: The furnace body cover (31) is provided with a water cooling groove (311) surrounding the cover frame (32), and the water cooling groove (311) is equipped with a water cooling pipeline for circulating cooling.

6. The miniature visual electric heating stove according to claim 1, characterized in that: A cross-shaped through groove is arranged in the middle of the sample tray (25) to place the sample while avoiding blocking light and infrared detection.

7. A miniature visual electric heating stove according to claim 1 or 6, characterized in that: The first ceramic spray layer (22) is an aluminum oxide and zirconium oxide composite ceramic spray layer; the nickel-chromium electric heating plate (23) and the second ceramic spray layer (24) are aluminum oxide ceramic spray layers.

8. The miniature visual electric heating stove according to claim 1, characterized in that: The glass assembly (13) comprises a lower glass baffle (131) and a pressing plate (132); a through opening (111) is provided on the bottom wall of the furnace shell (11); a clamping platform is provided at the lower interface of the through opening (111); the lower glass baffle (131) is clamped and matched with the clamping platform and fixed by the pressing plate (132).

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