Resistance heating device of test chamber

Abstract

The invention discloses a test chamber resistance heating device which comprises a furnace body capable of surrounding a test chamber, the furnace body is evenly divided into a plurality of areas in the circumferential direction and the axial direction, and each area is independently provided with a temperature measuring unit, a heating unit and an overtemperature ventilation unit; the temperature measuring unit is used for monitoring the temperature of the area where the temperature measuring unit is located and comprises a thermocouple which stretches into the furnace body in a sealed mode and is adjustable in stretching length. The heating unit is arranged on the inner wall of the furnace lining and is used for heating the area by using a resistor and independently controlling the temperature according to the feedback of the temperature measuring unit; the overtemperature ventilation unit is used for spraying cold air to the area for cooling when the temperature measurement unit monitors that the area is overtemperature, and comprises an air inlet pipe which extends into the furnace body in a sealing manner and of which the extending length is adjustable, an air inlet branch which is connected with the tail end of the air inlet pipe through a hose, and a valve assembly which is arranged on the air inlet branch and is used for controlling on-off and air volume; a cold source pipeline used for providing cold air for the air inlet branches of all the areas is arranged outside the furnace body. According to the device, uniform heating in the furnace can be realized, and the over-temperature phenomenon is overcome.

Description

Technical Field

[0001] The present invention relates to geotechnical engineering tests, and particularly to a resistance heating device for a test chamber. Background Art

[0002] With the continuous advancement of major infrastructure construction and resource and energy development towards deep underground and active geological structure areas, complex environments such as high in-situ stress, high osmotic pressure, high geothermal temperature, and strong engineering disturbances are faced. The difficulty of engineering construction exceeds that of the past, making the implementation of deep geotechnical engineering extremely difficult. Therefore, experimental research is required.

[0003] In order to simulate the deep multi-field coupling environment and engineering disturbance conditions on the ground, and accurately observe and control the evolution process of the discontinuous structure inside the rock mass and the external non-linear behavior, many geotechnical engineering disturbance simulation facilities have been developed for experimental research. The simulation facilities not only need to apply the required pressure load to the test chamber and control it precisely, but also need to apply the required temperature load to the test chamber and control it precisely. Due to the characteristics of the test chamber, such as large single-piece volume, large weight, and thick wall, if only the inside of the test chamber is heated, it is not conducive to rapid temperature rise and subsequent heat preservation. Therefore, some simulation facilities will design a resistance heating device, covering the test chamber with a furnace body and using resistance to heat the outer wall of the test chamber.

[0004] However, the current resistance heating device for the test chamber has the following problems: The volume of the test chamber itself is very large, and the volume of the furnace body covering the test chamber is even larger (the unfolded length of some furnace bodies is more than 9 meters and the height is more than 2.7 meters). The current resistances are all distributed and installed on the inner wall of the furnace body and controlled uniformly, which is very likely to cause uneven heating. The key is that the heating of the lower part will affect the upper part. The hot air rising from the lower part will cause over-temperature in the upper part, resulting in local over-temperature heating of the outer wall of the test chamber and affecting the test. Summary of the Invention

[0005] The purpose of the present invention is to provide a resistance heating device for a test chamber, which can achieve uniform heating in the furnace and overcome the over-temperature phenomenon.

[0006] The technical solution adopted by the present invention is: A test cabin resistance heating device comprises a furnace body capable of surrounding the test cabin, wherein the outer layer of the furnace body is a furnace shell and the inner layer is a furnace lining; the furnace body is evenly divided into a plurality of regions along the circumferential direction and the axial direction, each region is independently provided with a temperature measuring unit, a heating unit and an over-temperature ventilation unit; the temperature measuring unit is used for monitoring the temperature of the region, and comprises a thermocouple which is sealed and extends into the furnace body and has an adjustable extension length; the heating unit is arranged on the inner wall of the furnace lining, and is used for heating the region by resistance and performing independent temperature control according to feedback from the temperature measuring unit; the over-temperature ventilation unit is used for spraying cold air into the region for cooling when the temperature measuring unit detects that the region is over-temperature, and comprises an air inlet pipe which is sealed and extends into the furnace body and has an adjustable extension length, an air inlet branch connected to the rear end of the air inlet pipe through a hose, and a valve assembly which is arranged on the air inlet branch and controls on and off and the air volume, and a cold source pipeline for providing cold air to the air inlet branches of each region is arranged outside the furnace body.

[0007] Preferably, when working, each heating unit is turned on to quickly heat up the furnace, and under the feedback of the temperature measuring unit, the resistance heating power is controlled to make the area within the set temperature range. If the temperature measuring unit then detects that the area is over-temperature, the over-temperature ventilation unit is controlled by the valve assembly to spray cold air into the area for cooling, so that the area quickly returns to the set temperature range; after working, each heating unit is turned off, and if rapid cooling is required, each over-temperature ventilation unit is controlled to spray cold air simultaneously for cooling.

[0008] Preferably, the installation structures of the thermocouple and the air inlet pipe on the furnace body are the same, both including a mounting seat arranged on the outer wall of the furnace shell for parts to pass through the furnace shell, a sleeve arranged in the furnace lining for parts to pass through the furnace lining, a sealing assembly arranged on the mounting seat to allow the parts to pass through in a sealed manner, and a locking screw arranged on the mounting seat to lock the parts.

[0009] Preferably, the sealing assembly includes an inner pressure head, a high temperature resistant sealing packing 1, an outer pressure head and a compression sleeve, the sealing packing 1 is between the inner pressure head and the outer pressure head, the inner pressure head and the sealing packing 1 are located in the mounting seat, the outer pressure head is partially located in the mounting seat and partially extends out of the mounting seat, the compression sleeve is threadedly fitted on the end of the mounting seat and pressed on the outer pressure head, the outer pressure head, the sealing packing 1 and the inner pressure head are provided with through holes for parts to pass through, and when the compression sleeve squeezes the outer pressure head, the sealing packing 1 will be deformed under the clamping of the outer pressure head and the inner pressure head to achieve sealing.

[0010] Preferably, the air inlet pipe and the thermocouple are arranged at the midline position of the area, and the thermocouple is located above the air inlet pipe.

[0011] Preferably, the head end of the air inlet pipe adopts a bevel at a certain angle and is provided with a damping block.

[0012] Preferably, each zone is equipped with two thermocouples, one of which is used for temperature control and recording, and the other is used for over-temperature alarm.

[0013] Preferably, the heating unit includes a pair of hanging brackets, a mandrel arranged horizontally and vertically, ceramic discs and ceramic bushings that are non-rotatably sleeved on each mandrel and evenly distributed, and a number of helical resistance wires. One side of the hanging bracket is vertically distributed with clamping seats opening downward, and the other side is vertically distributed with supporting seats opening upward. The clamping seats are used to insert and install downward on the connecting members on the inner wall of the furnace lining. The two ends of the mandrel are supported on the same-layer supporting seats of the two side hanging brackets. Adjacent ceramic discs are separated by ceramic bushings and axially limited. Through holes are evenly distributed around the axis on the ceramic discs, and the through holes of each ceramic disc on the same mandrel are aligned. The resistance wires are distributed according to each row of through holes, and each resistance wire passes through a corresponding row of through holes.

[0014] Preferably, the mandrel is a square shaft, and square holes for clearance fit with the square shaft are provided at the centers of the ceramic disc and the ceramic bushing.

[0015] Preferably, threaded holes are provided on both end faces of the mandrel, and the anti-detachment pieces are installed on the end faces of the mandrel by screws fitting the threaded holes. The anti-detachment pieces are used to prevent the ceramic discs and the ceramic bushings from detaching from the mandrel.

[0016] Preferably, limiting holes are provided near both ends of the mandrel, and limiting members are installed in the limiting holes. The limiting members are used to axially limit the ceramic discs near the ends.

[0017] Preferably, the resistance wires pass through the through holes on the middle ceramic discs at the same time, and leave the through holes on the two end ceramic discs unpassed through.

[0018] Preferably, the furnace body adopts a split structure that is divided into two halves. Backrest frames are respectively fixedly connected to the outer sides of the two half furnace bodies. Walking mechanisms for closing and separating the furnace body and locking mechanisms for locking when the furnace body is closed are provided on both backrest frames. Two sets of cold source pipelines are respectively fixedly connected to both backrest frames and provide cold air for the air inlet branches on the corresponding side half furnace bodies. The cold sources of the two sets of cold source pipelines are respectively arranged on the corresponding side backrest frames.

[0019] Preferably, the walking mechanism includes walking wheels, a driving motor, and a transmission component. The locking mechanism includes a locking hole, a locking pin, and a hydraulic driving mechanism. When the two half furnace bodies are closed, the hydraulic driving mechanism drives the locking pin to insert into the locking hole. When the two half furnace bodies need to be separated, the hydraulic driving mechanism first drives the locking pin to withdraw from the locking hole, and then the driving motor drives the walking wheels through the transmission component to make the two half furnace bodies move away from each other.

[0020] Preferably, the cold source adopts a combination of a refrigerator and a blower. The blower extracts the cold air output by the refrigerator and then inputs it into the cold source pipeline.

[0021] The beneficial effects of the present invention are: The device adopts a modular design, fully considering the characteristics of the large size and large height of the furnace body. It is divided into multiple regions along the circumferential and axial directions, and each region has an independent temperature measurement unit, heating unit, and over-temperature ventilation unit. Therefore, each region can independently measure temperature, control temperature, and perform over-temperature ventilation, enabling uniform heating inside the furnace. The device adopts an over-temperature ventilation unit, fully considering the phenomenon of over-temperature in the upper part caused by the floating of hot air. Once this situation occurs, simply changing the power of the heating unit in the corresponding region is ineffective. This application uses the over-temperature ventilation unit to introduce external cold air and directly cool down through the cold air, overcoming the over-temperature phenomenon. In this device, the air inlet pipe and the thermocouple both extend into the furnace body in a sealed manner and the extension length is adjustable, which can not only prevent thermal short-circuit from damaging the furnace temperature uniformity but also adjust the air inlet pipe and the thermocouple to an appropriate extension length to achieve better performance. In this device, the tail end of the air inlet pipe is connected to the air inlet branch through a hose, providing a travel margin for the movement of the air inlet pipe. In this device, the heating unit is arranged on the inner wall of the furnace lining, which can avoid thermal short-circuit caused by direct connection with the furnace shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the front view of the resistance heating device of the test chamber in the present invention.

[0023] Figure 2 is Figure 1 the sectional view taken along line A - A in

[0024] Figure 3 is the top view of the resistance heating device of the test chamber in the present invention.

[0025] Figure 4 is the bottom view of the resistance heating device of the test chamber in the present invention.

[0026] Figure 5 is the front view of the installation of the cold source pipeline, air inlet branch, valve assembly, hose, and air inlet pipe on the half furnace body in the present invention.

[0027] Figure 6 is Figure 5 the top view of

[0028] Figure 7 is the installation schematic diagram of the air inlet pipe on the furnace body in the present invention.

[0029] Figure 8 is the installation schematic diagram of the thermocouple on the furnace body in the present invention.

[0030] Figure 9 is the front view of the heating unit in the present invention.

[0031] Figure 10 is the top view of the heating unit in the present invention.

[0032] Figure 11It is a side view of the heating unit in the present invention.

[0033] Figure 12 It is an installation diagram of the mandrel, ceramic disc, ceramic bushing and resistance wire in the heating unit of the present invention.

[0034] Figure 13 It is a schematic diagram of the mandrel in the heating unit of the present invention.

[0035] Figure 14 It is a schematic diagram of the resistance wire in the heating unit of the present invention.

[0036] Figure 15 It is a schematic diagram of the ceramic disc in the heating unit of the present invention.

[0037] Figure 16 It is a schematic diagram of the ceramic bushing in the heating unit of the present invention.

[0038] In the figure: 1 - back support frame; 2 - cold source pipeline; 3 - half furnace body; 4 - cold source; 5 - walking wheel; 6 - drive motor; 7 - transmission component; 8 - hydraulic drive mechanism; 9 - locking pin; 10 - thermocouple; 11 - air inlet branch; 12 - heating unit; 13 - furnace lining; 14 - furnace shell; 15 - valve assembly; 16 - hose; 17 - AD quick connector; 18 - air inlet pipe; 19 - locking screw; 20 - compression sleeve; 21 - outer pressure head; 22 - sealing packing one; 23 - mounting seat; 24 - inner pressure head; 25 - sleeve; 26 - damping block; 27 - hanging rack; 28 - screw; 29 - anti - detachment piece; 30 - mandrel; 31 - ceramic disc; 32 - resistance wire; 33 - ceramic bushing; 34 - clamping seat; 35 - supporting seat; A - test chamber; a - limiting hole; b - through hole; c - square hole. Detailed implementation manners

[0039] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated herein can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0041] It should be noted that like reference numerals and letters refer to like items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the figures, or the orientation or positional relationship in which the product of this application is customarily placed during use. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application. In addition, the terms "XXX one", "XXX two", etc. are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0043] The features and performance of the present application will be further described in detail below in conjunction with embodiments.

[0044] Embodiment 1 The present application discloses a resistance heating device for a test chamber, as Figures 1 to 4 shown. Its main body is a furnace body that can surround the test chamber A. The outer layer of the furnace body is a furnace shell 14, and the inner layer is a furnace lining 13. The furnace body is evenly divided into multiple regions in the circumferential and axial directions, and each region is independently provided with a temperature measurement unit, a heating unit 12, and an over-temperature ventilation unit; Among them: The temperature measurement unit is used to monitor the temperature of the region where it is located, including a thermocouple 10 that is sealed and extends into the furnace body with an adjustable extension length, as shown in Figure 1 and Figure 8 ; The heating unit 12 is arranged on the inner wall of the furnace lining 13 and is used to heat the region where it is located by resistance and independently control the temperature according to the feedback of the temperature measurement unit, as shown in Figure 2 ; The over-temperature ventilation unit is used to spray cold air into the region where it is located for cooling when the temperature measurement unit monitors that the temperature of the region where it is located exceeds the limit. It includes an air inlet pipe 18 that is sealed and extends into the furnace body with an adjustable extension length, an air inlet branch 11 connected to the tail end of the air inlet pipe 18 through a hose 16, and a valve assembly 15 arranged on the air inlet branch 11 to control the on-off and air volume. A cold source pipeline 2 is arranged outside the furnace body to supply cold air to the air inlet branches 11 of each region, as shown in Figures 1 to 6 .

[0045] According to the above scheme, it can be known that: The device adopts modular design, taking full account of the large size and height of the furnace body, and divides it into multiple areas along the circumferential and axial directions, and each area has an independent temperature measurement unit, heating unit 12 and over-temperature ventilation unit, so each area can independently perform temperature measurement, temperature control and over-temperature ventilation, and can achieve uniform heating in the furnace; The device adopts an over-temperature ventilation unit, which fully considers the phenomenon of over-temperature in the upper part caused by the rising of hot air. Once this situation is formed, simply changing the power of the heating unit 12 in the area is ineffective. The present application utilizes the over-temperature ventilation unit to introduce external cold air, and directly cools down through the cold air, thereby overcoming the over-temperature phenomenon.

[0046] in addition: In the device, the air inlet pipe 18 and the thermocouple 10 are both sealed and extended into the furnace body, and the extension length is adjustable, which can prevent thermal short circuit from destroying the uniformity of furnace temperature, and can also adjust the air inlet pipe 18 and the thermocouple 10 to a suitable extension length to achieve better performance; In this device, the tail end of the air inlet pipe 18 is connected to the air inlet branch 11 through a hose 16, providing a travel margin for the movement of the air inlet pipe 18; in this device, the heating unit 12 is arranged on the inner wall of the furnace lining 13, which can avoid direct connection with the furnace shell 14 to cause thermal short circuit.

[0047] The working method of the device is: when working, each heating unit 12 is turned on to quickly heat up the furnace, and under the feedback of the temperature measuring unit, the resistance heating power is controlled to make the area within the set temperature range (250℃±2.5℃). After that, if the temperature measuring unit detects that the area is over-temperature, the valve assembly 15 controls the over-temperature ventilation unit to spray cold air to the area for cooling, so that the area quickly returns to the set temperature range; after working, turn off each heating unit 12, and if rapid cooling is required, control each over-temperature ventilation unit to spray cold air to cool at the same time.

[0048] For safety and heat insulation reasons, the electrical control room of the entire device is far away from the furnace body. In order to prevent the signal attenuation caused by the long distance from affecting the temperature control accuracy, a temperature transmitter is installed near the furnace body.

[0049] Regarding the structure of the furnace body, in this embodiment, preferably: like Figures 1 to 4As shown in the figure, the furnace body adopts a split structure that is divided into two halves. On the outer sides of the two half furnace bodies 3, back support frames 1 are fixedly connected respectively. On both sides of the back support frames 1, there are traveling mechanisms for enclosing and separating the furnace body, and locking mechanisms for locking when the furnace body is enclosed. Two sets of cold source pipelines 2 are fixedly connected to the back support frames 1 on both sides and provide cold air for the air inlet branch 11 on the corresponding side half furnace body 3. The cold sources 4 of the two sets of cold source pipelines 2 are respectively arranged on the back support frames 1 on the corresponding sides. When the two half furnace bodies 3 are enclosed, the locking mechanism is used to ensure locking and the back support frame 1 is used to provide back support, which can ensure the safety and stability of the test. When maintenance or sample extraction is required, the two half furnace bodies 3 can be separated.

[0050] As Figures 1 to 4 shown in the figure, the traveling mechanism includes traveling wheels 5, drive motors 6 and transmission components 7. The locking mechanism includes locking holes, locking pins 9 and hydraulic drive mechanisms 8. When the two half furnace bodies 3 are enclosed, the hydraulic drive mechanism 8 drives the locking pin 9 to insert into the locking hole. When the two half furnace bodies 3 need to be separated, the hydraulic drive mechanism 8 first drives the locking pin 9 to withdraw from the locking hole, and then the drive motor 6 drives the traveling wheels 5 through the transmission components 7 to make the two half furnace bodies 3 move away from each other.

[0051] In order to avoid air leakage at the docking place, a sealing groove is provided at the docking place of the two half furnace bodies 3, and a high-temperature resistant sealing filler II is arranged in the sealing groove. The sealing filler II can adopt a soft temperature-resistant fiber packing with an internal metal wire.

[0052] Regarding the structure of the furnace lining 13, in this embodiment, preferably: The furnace lining 13 includes refractory fiber paper and refractory ceramic fiber modules laid in sequence on the inner wall of the furnace shell 14. When the refractory ceramic fiber modules are heated at high temperature, they expand internally, causing them to press against each other and form a solidified hard layer on the surface. No gaps are generated after long-term high-temperature use, and the solidified hard layer generated on the surface after high temperature has good strength, erosion resistance and long service life. Refractory fiber Weidun modules can be used, which expand internally and form a solidified hard layer on the surface when heated to 160°C.

[0053] Regarding the over-temperature ventilation unit, in this embodiment, preferably: As Figure 7 shown in the figure, the head end of the air inlet pipe 18 adopts an inclined opening at a certain angle (30 degrees) and is equipped with a damping block 26. The jet orifice of the air inlet pipe 18 adopts a diffusing and damping structure to prevent the cold air from directly spraying on the hot test chamber and causing temperature difference.

[0054] The cold source 4 adopts a combination of a refrigerating machine and a blower. The blower extracts the cold air output by the refrigerating machine and then inputs it into the cold source pipeline 2. The hose 16 adopts a stainless steel braided hose 16. The hose 16 and the air inlet pipe 18 adopt an AD quick connector 17, which is convenient for installation and adjustment. The valve assembly 15 adopts a manual regulating valve + an automatic control regulating valve, and the manual regulating valve can be used during maintenance and in emergency situations.

[0055] Regarding the heating power, in this embodiment, preferably: The entire furnace body is evenly divided into 10 parts in the circumferential direction and 3 layers in the axial direction, forming a total of 30 regions. Each of the two half furnace bodies 3 has 15 regions, and a heating unit 12 is arranged in each region. Since the furnace temperature is relatively low and the heating time is relatively long, the total heating power of the heating unit 12 is determined to be 450 kw, that is, the heating power of each heating unit 12 is 15 kw. Since the heating power of a single heating unit 12 is relatively small, single-phase heating can be used for each heating under normal circumstances. However, considering that the number of regions is too large and uneven loading is likely to occur in the regions, three-phase heating is still adopted for each heating unit 12.

[0056] Regarding the installation structures of the thermocouple 10 and the air inlet pipe 18 on the furnace body, in this embodiment, preferably: As Figure 7 and Figure 8 shown, the installation structures of the thermocouple 10 and the air inlet pipe 18 on the furnace body are the same, and both include a mounting seat 23 provided on the outer wall of the furnace shell 14 for parts to pass through the furnace shell 14, a sleeve 25 provided in the furnace lining 13 for parts to pass through the furnace lining 13, a sealing assembly provided on the mounting seat 23 for the parts to pass through the mounting seat 23 in a sealed manner, and a locking screw 19 provided on the mounting seat 23 for locking the position of the parts; the mounting seat 23 and the sealing assembly can achieve sealing, the sleeve 25 can prevent the furnace lining 13 from expanding due to heat and damaging the thermocouple 10 or the air inlet pipe 18, and the locking screw 19 can lock the position after adjusting the insertion angle. The sleeve 25 can be made of ceramic material or stainless steel. If ceramic material is used, heat insulation can be achieved. The air inlet pipe 18 and the thermocouple 10 can be made of stainless steel.

[0057] As Figure 7 and Figure 8 shown, the sealing assembly includes an inner pressure head 24, a high-temperature-resistant sealing packing 22, an outer pressure head 21, and a compression sleeve 20. The sealing packing 22 is located between the inner pressure head 24 and the outer pressure head 21. The inner pressure head 24 and the sealing packing 22 are located inside the mounting seat 23. The outer pressure head 21 is partially located inside the mounting seat 23 and partially extends out of the mounting seat 23. The compression sleeve 20 is threadedly fitted on the end of the mounting seat 23 and presses on the outer pressure head 21. Through holes b for parts to pass through are provided on the outer pressure head 21, the sealing packing 22, and the inner pressure head 24. When the compression sleeve 20 presses the outer pressure head 21, the sealing packing 22 will deform under the clamping of the outer pressure head 21 and the inner pressure head 24 to achieve sealing. The sealing packing 22 is deformed by clamping and adjusted and locked by threaded fitting. The sealing packing 22 can be made of asbestos rope, which is high-temperature-resistant.

[0058] As Figure 1 shown, the air inlet pipe 18 and the thermocouple 10 are arranged at the midline position of the region where they are located, and the thermocouple 10 is above the air inlet pipe 18.

[0059] Regarding the structure of the heating unit 12, in the present embodiment, preferably: As Figures 9 to 16 shown, the heating unit 12 includes a pair of hanging brackets 27, a mandrel 30 disposed horizontally and vertically, ceramic discs 31 and ceramic bushings 33 that are non-rotatably fitted over each mandrel 30 and evenly distributed, several resistance wires 32 in a spiral shape, a clamping seat 34 with a downward opening vertically distributed on one side of the hanging bracket 27, and a supporting seat 35 with an upward opening vertically distributed on the other side. The clamping seat 34 is used to insert and install downward on the connecting member on the inner wall of the furnace lining 13. The two ends of the mandrel 30 are supported on the same-layer supporting seats 35 of the two-side hanging brackets 27. The adjacent ceramic discs 31 are separated by ceramic bushings 33 and axially limited. Through holes b are evenly distributed around the axis on the ceramic discs 31. The through holes b of the ceramic discs 31 on the same mandrel 30 are aligned. The resistance wires 32 are distributed according to each row of through holes b, and each resistance wire 32 passes through a corresponding row of through holes b. Currently, the resistors are all installed on the insulating porcelain tubes in a winding manner, and the insulating porcelain tubes are installed on the inner wall of the cover body one by one. The loading and unloading of all the resistors are inconvenient. The insulating porcelain body will shield the rear area of the resistor, reducing the heating efficiency. Moreover, only one resistor is installed on the same insulating porcelain tube, and the installation amount of the resistor per unit space is small, affecting the overall heating efficiency. In this heating unit 12, the resistance wire 32 can be drawn out or put into a row of through holes b. The mandrel 30 can be directly placed downward on the hanging bracket 27 or taken out upward. The hanging bracket 27 can be directly inserted downward on the connecting member on the inner wall of the cover body and taken out upward, which is convenient for loading and unloading, maintenance, and replacement. In this heating unit 12, the resistance wire 32 is in a spiral shape, and the heating efficiency is high. The key is that the resistance wire 32 only passes through a row of through holes b and is not installed on the insulating porcelain tube. Therefore, it is basically suspended and not shielded, ensuring the heating effect. Moreover, multiple resistance wires 32 can be installed on the same mandrel 30, and the installation amount of the resistor per unit space is large, further improving the heating efficiency.

[0060] As Figure 13 、 Figure 15 、 Figure 16 shown, the mandrel 30 is a square shaft, and square holes c for clearance fit with the square shaft are provided at the centers of the ceramic discs 31 and the ceramic bushings 33. The fit between the square shaft and the square holes c can prevent the ceramic discs 31 and the ceramic bushings 33 from rotating and causing damage to the resistance wire 32, and the clearance fit facilitates the installation of the ceramic discs 31 and the ceramic bushings 33.

[0061] As Figures 9 to 13 ​As shown, threaded holes are provided on both end faces of the mandrel 30. The anti - detachment piece 29 is installed on the end face of the mandrel 30 by screwing the screw 28 into the threaded hole. The anti - detachment piece 29 is used to prevent the ceramic disc 31 and the ceramic bushing 33 from detaching from the mandrel 30. During the loading and unloading process, it is impossible to ensure that the mandrel 30 is horizontal throughout the process. Therefore, the ceramic disc 31 and the ceramic bushing 33 may detach from the mandrel 30 along the inclined direction. The anti - detachment piece 29 is provided to prevent the two from detaching from the mandrel 30.

[0062] As Figure 10 、 Figure 12 、 Figure 13 shown, limit holes a are provided near both ends of the mandrel 30. The limiting parts are installed in the limit holes a. The limiting parts are used to axially limit the ceramic disc 31 near the end to prevent the ceramic disc 31 from moving horizontally and being damaged during the test vibration.

[0063] As Figure 9 、 Figure 10 、 Figure 12 shown, the resistance wire 32 passes through the through - hole b on the middle ceramic disc 31 while leaving the through - hole b on the two end ceramic discs 31 not passed through, to avoid the resistance wire 32 being too close and causing the hanging bracket 27 to deform at high temperature. The two end ceramic discs 31 can play a role in preventing high - temperature radiation to the hanging bracket 27.

[0064] The hanging bracket 27 and the mandrel 30 are made of stainless steel, which is resistant to temperature and corrosion. The resistance wire 32 is made of high - nickel Cr20Ni80 material, which has a long service life and is convenient for processing. Since the resistance wire 32 is prone to damage during long - term use, a better material is selected. The ceramic disc 31 and the ceramic bushing 33 are made of high - temperature - resistant sintered corundum material, which is resistant to temperature, not easily damaged, and has a long life.

[0065] The resistance wire 32 is 200 - 300 mm away from the outer wall of the test chamber A. If it is too close, when the resistance wire 32 breaks, it is easy to touch the workpiece and cause an electrical short - circuit, and the local radiation temperature will be too high. If it is too far, it will waste space and cause large heat loss.

[0066] The loading and unloading method of the heating unit 12 is as follows: During installation, first use the card seat 34 to insert the hanging bracket 27 downward and install it on the connecting member on the inner wall of the furnace lining 13. Alternately sleeve the ceramic disc 31 and the ceramic bushing 33 on the mandrel 30 and ensure that the through - holes b of the ceramic discs 31 on the same mandrel 30 are aligned. Then pass the resistance wire 32 through the corresponding row of through - holes b. Then place the assembled mandrel 30 downward on the same - layer support 35 of the two - side hanging brackets 27. When the resistance wire 32 needs to be replaced, after the temperature drops, first take out the mandrel 30 upward, then pull out the resistance wire 32 to be replaced, then pass the new resistance wire 32 through the corresponding row of through - holes b, and then place the assembled mandrel 30 downward on the same - layer support 35 of the two - side hanging brackets 27.

[0067] Embodiment Two The difference between this embodiment and the first embodiment is that each area is equipped with two thermocouples 10, one of which is used for temperature control and recording, and the other is used for over-temperature alarm, improving the safety redundancy.

[0068] The embodiments described above are some, but not all, of the embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

Claims

1. A test chamber resistance heating device, comprising a furnace body capable of surrounding the test chamber, wherein the outer layer of the furnace body is a furnace shell and the inner layer is a furnace lining; characterized in that: The furnace body is evenly divided into multiple areas along the circumferential and axial directions, and each area is independently provided with a temperature measuring unit, a heating unit and an over-temperature ventilation unit; the temperature measuring unit is used to monitor the temperature of the area, including a thermocouple that is sealed and extends into the furnace body with an adjustable extension length; the heating unit is arranged on the inner wall of the furnace lining, and is used to heat the area using resistance and independently control the temperature according to the feedback of the temperature measuring unit; the over-temperature ventilation unit is used to spray cold air into the area for cooling when the temperature measuring unit detects that the area is over-temperature, including an air inlet pipe that is sealed and extends into the furnace body with an adjustable extension length, an air inlet branch connected to the rear end of the air inlet pipe through a hose, and a valve assembly arranged on the air inlet branch for controlling on-off and air volume, and a cold source pipeline for providing cold air to the air inlet branches of each area is provided outside the furnace body.

2. The test chamber resistance heating device according to claim 1, characterized in that: During operation, each heating unit is turned on to quickly heat up the furnace, and under the feedback of the temperature measuring unit, the resistance heating power is controlled to keep the area within the set temperature range. If the temperature measuring unit detects that the area is over-temperature, the over-temperature ventilation unit is controlled by the valve assembly to spray cold air to the area for cooling, so that the area quickly returns to the set temperature range; after operation, each heating unit is turned off, and if rapid cooling is required, each over-temperature ventilation unit is controlled to spray cold air to cool the area at the same time.

3. The test chamber resistance heating device according to claim 1, characterized in that: The installation structures of the thermocouple and the air inlet pipe on the furnace body are the same, both of which include a mounting seat arranged on the outer wall of the furnace shell for parts to pass through the furnace shell, a sleeve arranged in the furnace lining for parts to pass through the furnace lining, a sealing assembly arranged on the mounting seat to allow the parts to pass through in a sealed manner, and a locking screw arranged on the mounting seat to lock the parts.

4. The test chamber resistance heating device according to claim 3, characterized in that: The sealing assembly includes an inner pressure head, a high temperature resistant sealing packing 1, an outer pressure head and a compression sleeve. The sealing packing 1 is between the inner pressure head and the outer pressure head. The inner pressure head and the sealing packing 1 are located in the mounting seat. The outer pressure head is partially located in the mounting seat and partially extends out of the mounting seat. The compression sleeve is threadedly fitted on the end of the mounting seat and pressed on the outer pressure head. The outer pressure head, the sealing packing 1 and the inner pressure head are provided with through holes for parts to pass through. When the compression sleeve squeezes the outer pressure head, the sealing packing 1 will be deformed under the clamping of the outer pressure head and the inner pressure head to achieve sealing.

5. The test chamber resistance heating device according to claim 1, characterized in that: The air inlet pipe and the thermocouple are arranged at the midline position of the area, and the thermocouple is located above the air inlet pipe.

6. The test chamber resistance heating device according to claim 1, characterized in that: The first end of the air inlet pipe adopts a bevel opening at a certain angle and is provided with a damping block.

7. The test chamber resistance heating device according to claim 1, characterized in that: Each zone is equipped with two thermocouples, one of which is used for temperature control and recording, and the other is used for over-temperature alarm.

8. The test chamber resistance heating device according to claim 1, characterized in that: The heating unit includes a pair of hangers, a horizontally and vertically distributed core shaft, ceramic discs and ceramic sleeves that are non-rotatably fitted on each core shaft and evenly distributed, and a number of spiral resistance wires. A downward-opening holder is vertically distributed on one side of the hanger, and an upward-opening bracket is vertically distributed on the other side. The holder is used to be inserted downward on a connecting component installed on the inner wall of the furnace lining. Both ends of the core shaft are supported on the same-layer brackets of the hangers on both sides. Adjacent ceramic discs are separated and axially limited by ceramic sleeves. Through holes are evenly distributed on the ceramic discs around the axis. The through holes of each ceramic disc on the same core shaft are aligned. The resistance wires are distributed according to each row of through holes and each resistance wire passes through a corresponding row of through holes.

9. The test chamber resistance heating device according to claim 8, characterized in that: The core shaft adopts a square shaft, and the centers of the ceramic disc and the ceramic sleeve are both provided with square holes for clearance matching with the square shaft.

10. The test chamber resistance heating device according to claim 8, characterized in that: The two end faces of the mandrel are provided with threaded holes, and the screws cooperate with the threaded holes to install the anti-dropping piece on the end face of the mandrel. The anti-dropping piece is used to prevent the ceramic disc and the ceramic sleeve from falling off from the mandrel.

11. The test chamber resistance heating device according to claim 8, characterized in that: Limiting holes are arranged near the two ends of the core shaft, and limiting members are installed on the limiting holes. The limiting members are used to axially limit the ceramic disc near the end.

12. The test chamber resistance heating device according to claim 8, characterized in that: The resistance wire passes through the through hole on the middle ceramic disc at the same time, leaving the through holes on the ceramic discs at both ends unpassed.

13. The test chamber resistance heating device according to claim 1, characterized in that: The furnace body adopts a split structure divided into two halves, and the outer sides of the two half furnace bodies are respectively fixedly connected with back support frames. The back support frames on both sides are provided with a walking mechanism for closing and separating the furnace body and a locking mechanism for locking the furnace body when it is closed. Two sets of cold source pipelines are respectively fixedly connected to the back support frames on both sides and provide cold air for the air inlet branch on the half furnace body on that side. The cold sources of the two sets of cold source pipelines are respectively arranged on the back support frames on that side.

14. The test chamber resistance heating device according to claim 13, characterized in that: The traveling mechanism includes traveling wheels, a driving motor and a transmission assembly, and the locking mechanism includes a locking hole, a locking pin and a hydraulic driving mechanism; when the two half furnace bodies are enclosed, the hydraulic driving mechanism drives the locking pin to be inserted into the locking hole; when the two half furnace bodies need to be separated, the hydraulic driving mechanism first drives the locking pin to withdraw from the locking hole, and then the driving motor drives the traveling wheel through the transmission assembly to make the two half furnace bodies move away from each other.

15. The test chamber resistance heating device according to claim 13, characterized in that: The cold source adopts the combination of a refrigerator and a blower. The blower draws the cold air output by the refrigerator and inputs it into the cold source pipeline.

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