A test device for the performance of thermal insulation coatings

Abstract

This utility model discloses a heat insulation coating performance testing device, relating to the field of heat insulation coating technology. The utility model includes a heating chamber and a control console. The control console is connected to one side of the heating chamber. The front of the heating chamber has a heating chamber and a door corresponding to the heating chamber, hinged to it. A fixed box is mounted on the upper side of the heating chamber. A cooling assembly corresponding to the heating chamber is connected to the back of the heating chamber. Multiple heating racks are mounted on the lower side of the heating chamber, each containing a heater. Elastic compression assemblies corresponding to the multiple heating racks are installed inside the fixed box. This utility model uses a cam and roller mechanism to reduce the friction between the cam and the lifting plate during compression. It also facilitates the motor control of multiple cover plates to descend, enabling simultaneous fixing and testing of multiple samples. The elastic sliding of the lifting plate allows for quick repositioning of the rollers and cover plates after the cam rotates out of alignment.

Description

Technical Field

[0001] This utility model belongs to the field of heat insulation coatings, specifically, it relates to a heat insulation coating performance testing device. Background Technology

[0002] The thermal insulation coating performance testing device is an experimental device specifically designed to evaluate the thermal performance of thermal insulation coatings. Its core function is to simulate actual use environments and quantify key parameters such as the thermal insulation effect, temperature resistance, and reflectivity of the coating.

[0003] Chinese patent CN222561552U discloses a testing device for the thermal insulation performance of exterior wall coatings, comprising: a test chamber, a heating device fixedly installed on the top surface of the test chamber, a partition structure fixedly provided on the surface of the test chamber, and a controller fixedly installed on one side surface of the test chamber.

[0004] The exterior wall coating thermal insulation performance testing device disclosed in the application involves applying test coating to the surface of a test board and then inserting the test board into a test box through a slot for testing. Since the device tests a single test board each time, when it is necessary to conduct comparative tests on the thermal insulation performance of different coating thicknesses, the experimental personnel need to repeatedly perform the disassembly and replacement of the test board, which can easily affect the testing efficiency of the thermal insulation coating. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a heat insulation coating performance testing device, which solves the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by this utility model is as follows:

[0007] A heat insulation coating performance testing device includes: a heating chamber and a control console. The control console is connected to one side of the heating chamber. The front of the heating chamber has a heating chamber and a door corresponding to the heating chamber is hinged. A handle is provided on one side of the door. A fixed box is installed on the upper side of the heating chamber. A cooling component corresponding to the heating chamber is connected to the back of the heating chamber. Multiple heating racks are installed on the lower side of the heating chamber. Heaters are installed inside the heating racks. Elastic compression components corresponding to the multiple heating racks are installed inside the fixed box. The lower part of the elastic compression components is located inside the heating chamber.

[0008] The elastic compression assembly includes a motor and a lifting plate. The motor is installed on one side of the inner wall of the fixed box. The lifting plate slides elastically within the fixed box. A cam is fixedly connected to the motor output shaft. A roller corresponding to the cam is rotatably fitted on the upper part of the lifting plate. A lifting column corresponding to the heating frame is provided on the lower side. The lower end of the lifting column extends into the heating chamber. A lifting cylinder is installed on the lower end face of the lifting column. The lifting cylinder slides slidably within the heating chamber. An adjusting column slides elastically within the lifting cylinder. The lower end of the adjusting column extends to the outside of the lifting cylinder. A cover plate is installed on the lower end face of the adjusting column. A temperature sensor is embedded in the lower side of the cover plate. The temperature sensor is located above the corresponding heating frame. The heater, temperature sensor, and motor are all electrically connected to the control console.

[0009] Optionally, a connecting rod is provided on one end face of the cam, the cam is located between the motor and the connecting rod, a bearing is installed around the connecting rod, and a fixing cylinder is installed on one side of the inner wall of the fixing box, with the fixing cylinder installed around the bearing.

[0010] Optionally, the upper side of the heating box is provided with a slot corresponding to the lifting column, the slot is connected to the heating chamber, and the lifting column passes through the slot.

[0011] Optionally, a U-shaped frame is installed on the upper side of the lifting plate, and a fixing rod is provided between the two sides of the inner wall of the U-shaped frame, with rollers rotating and engaging around the fixing rod.

[0012] Optionally, sliders are provided on both sides of the lifting plate, and grooves are provided on both sides of the inner wall of the fixed box. The sliders slide in the corresponding grooves. Multiple first springs are installed between the lifting plate and the upper side of the heating box, and the first springs are sleeved on the periphery of the corresponding lifting column.

[0013] Optionally, the lifting cylinder is provided with a channel, and a lifting plate is slidably fitted in the channel. A second spring is installed between the lifting plate and the upper end face of the channel, and an adjusting column is installed on the lower end face of the lifting plate.

[0014] Optionally, the door is provided with a horizontal observation slot that runs through the door. A transparent plate is installed inside the observation slot. A sealing strip corresponding to the heating chamber is installed on one side of the door. The door is located between the sealing strip and the handle.

[0015] Optionally, the cooling assembly includes a liquid nitrogen storage tank, a heating chamber located between the liquid nitrogen storage tank and the chamber door, a liquid nitrogen pump installed on the liquid nitrogen storage tank, a liquid delivery pipe connected to one side of the liquid nitrogen pump, a diffusion hood installed on the back of the heating chamber, the end of the liquid delivery pipe away from the liquid nitrogen pump connected to one side of the diffusion hood, and multiple through holes connected to the diffusion hood on one side of the heating chamber.

[0016] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art. Of course, any product implementing the present invention does not necessarily need to achieve all of the following advantages at the same time:

[0017] By using a cam and rollers in conjunction, the friction between the cam and the lifting plate is reduced during cam compression. This also facilitates the motor's control of multiple cover plates to descend, enabling simultaneous fixation and testing of multiple samples. The elastic sliding of the lifting plate allows for quick resetting of the rollers and cover plates after cam misalignment. The elastic sliding of the adjusting column within the lifting cylinder allows the cover plates to adapt to the fixation requirements of heat insulation coatings or samples of different thicknesses, thus enabling the device to test heat insulation coatings or samples of various thicknesses simultaneously.

[0018] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings. Attached Figure Description

[0019] The accompanying drawings described below are merely some embodiments. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0020] In the picture:

[0021] Figure 1 This is a schematic diagram of the three-dimensional structure of the heating box;

[0022] Figure 2 This is a schematic diagram of the cross-sectional structure of the heating box;

[0023] Figure 3 This is a schematic diagram of the three-dimensional structure of a liquid nitrogen storage tank;

[0024] Figure 4 This is a schematic diagram of the cross-sectional structure of the elastic compression assembly.

[0025] The attached diagram lists the components represented by each number as follows:

[0026] Heating box 1, box door 2, handle 3, fixed box 4, control console 5, liquid nitrogen storage tank 6, liquid nitrogen pump 7, infusion tube 8, diffuser 9, heating rack 10, heater 11, motor 12, cam 13, roller 14, lifting plate 15, lifting column 16, lifting cylinder 17, second spring 18, adjusting column 19, cover plate 20, temperature sensor 21, first spring 22.

[0027] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] In the field of thermal insulation coating performance testing, existing technologies mainly rely on combinations of traditional thermal testing equipment and pressure application systems to meet the evaluation needs of coating thermal insulation performance under different application scenarios. These devices are typically used for coating research and quality control in areas such as building exterior walls, industrial pipelines, and aerospace equipment. Their core functions include simulating temperature changes in actual use environments, measuring the thermal resistance characteristics of the coating, and verifying long-term temperature resistance. A typical testing device consists of a heating module, a pressure regulation mechanism, a temperature monitoring system, and an auxiliary cooling unit. However, in practical applications, the design and coordinated operation of these modules still have certain limitations.

[0031] Traditional heating modules typically use resistance wires or infrared radiation plates as heat sources, heating the sample through a constant temperature chamber or local heater. For example, testing equipment commonly used in the construction industry usually places paint samples in a closed heating chamber, using PID temperature control technology to maintain a set temperature (e.g., 50℃ to 300℃), and monitoring the surface temperature through thermocouples or infrared sensors. While this design achieves basic temperature control, it suffers from deficiencies in high-temperature uniformity, especially in the edge areas of large samples where temperature differences (±5℃ or more) are prone to occur, leading to errors in thermal resistance calculations. Furthermore, the heater's power response speed is slow, making it difficult to quickly adapt to dynamic temperature changes (such as sudden temperature rise or fall test scenarios).

[0032] The pressure application mechanism is a key component of the testing device, ensuring close contact between the coating and the substrate to simulate actual adhesion. Common pressure adjustment methods in existing technologies include mechanical screw pressurization, pneumatic actuators, or hydraulic systems. For example, some industrial-grade testing equipment uses a manually rotated screw to drive a pressure plate downwards, displaying the pressure value on a dial. While this method is simple in structure, it suffers from low pressure accuracy (error exceeding ±10%) and low operational efficiency, especially during batch testing where repeated manual adjustments are required. Other devices use pneumatic actuators for automated pressure application, but their fixed stroke limits their application to samples with specific thicknesses (e.g., 1–3 mm). For ultra-thin coatings (<0.5 mm) or thick substrates (>5 mm), pressure overload or poor contact can easily lead to test failure. Furthermore, pneumatic systems experience significant pressure fluctuations, requiring frequent calibration to maintain stability.

[0033] The design of a temperature monitoring system directly affects the reliability of test data. Current technologies mostly employ contact temperature measurement (such as K-type thermocouples) or non-contact infrared temperature measurement. Contact temperature measurement requires the sensor to be directly attached to the sample surface, which may introduce errors due to uneven installation pressure or contact thermal resistance. While non-contact infrared temperature measurement avoids physical contact, it is sensitive to the emissivity of the sample surface and is easily affected by environmental radiation interference. Some high-end equipment attempts to integrate multi-channel temperature acquisition systems, using array sensors to increase data density, but the high cost and complex data processing limit its widespread adoption in conventional laboratories.

[0034] The cooling module is designed to rapidly reduce the temperature of samples after testing to simulate thermal cycling or accelerate the aging process in real-world environments. Common cooling methods include natural convection, forced air cooling, or water cooling systems. For example, some devices install cooling fans on the side walls of the heating chamber to accelerate cooling through air circulation, but the cooling rate is slow (it takes more than 30 minutes to drop from 200°C to room temperature) and it is difficult to achieve uniform cooling (temperature difference ±10°C). Water cooling systems can improve cooling efficiency, but their complex structure and the risk of leakage make them particularly unsuitable for electrical equipment or humidity-sensitive environments. In recent years, liquid nitrogen jet cooling technology has been introduced into some high-end equipment, rapidly absorbing heat through a cryogenic medium; however, the safety requirements for liquid nitrogen storage and transportation are high, and the cost is difficult to control.

[0035] In terms of structural integration, existing testing equipment often suffers from insufficient modularity. Heating, pressurizing, and cooling units are mostly designed as separate units, resulting in bulky equipment and cumbersome operating procedures. For example, a typical type of equipment requires separate operation of the heating controller, pressure regulating valve, and cooling switch, increasing the risk of human error. In addition, wear and tear on mechanical transmission components (such as screws and gears) accumulates over time, affecting long-term testing accuracy and requiring regular maintenance or replacement, further increasing operating costs.

[0036] Existing technologies still have limitations in adaptability to diverse testing needs. For example, architectural coatings testing typically focuses on changes in thermal resistance within a range of room temperature to 100°C, while aerospace coatings need to withstand extreme temperature cycling from -50°C to 500°C. Existing equipment often meets specific needs by replacing different heating modules or customizing chambers, lacking a universal design. Furthermore, there is insufficient support for testing flexible or curved substrates (such as pipe coatings), and traditional flat pressure plates struggle to achieve uniform pressure, leading to data that deviates from actual application results.

[0037] Intelligent operation and data integration capabilities are also shortcomings of existing technologies. Although some devices are equipped with basic data recording functions, they are mostly limited to single-parameter storage (such as temperature-time curves), lacking synchronous analysis and visualization of multi-dimensional data such as pressure and cooling rate. The user interface usually relies on physical buttons or simple displays, resulting in a poor user experience and making it difficult to achieve remote control or automated test process arrangement.

[0038] In summary, existing thermal insulation coating performance testing devices still have significant room for improvement in terms of heating uniformity, pressure control accuracy, cooling efficiency, and system integration. The industry urgently needs a testing solution that can balance high precision, high adaptability, and ease of operation to meet the increasingly complex demands of coating research and development and quality control.

[0039] Please see Figure 1-4 As shown, this embodiment provides a heat insulation coating performance testing device, including: a heating chamber 1 and a control console 5. The control console 5 is connected to one side of the heating chamber 1. The front of the heating chamber 1 is provided with a heating chamber and a door 2 corresponding to the heating chamber is hinged. A handle 3 is provided on one side of the door 2. A fixed box 4 is installed on the upper side of the heating chamber 1. A cooling component corresponding to the heating chamber is connected to the back of the heating chamber 1. Multiple heating racks 10 are installed on the lower side of the heating chamber. Heaters 11 are provided inside the heating racks 10. Elastic pressing components corresponding to the multiple heating racks 10 are provided inside the fixed box 4. The lower part of the elastic pressing components is located inside the heating chamber.

[0040] The elastic compression assembly includes a motor 12 and a lifting plate 15. The motor 12 is installed on one side of the inner wall of the fixed box 4. The lifting plate 15 slides elastically inside the fixed box 4. The output shaft of the motor 12 is fixedly connected to a cam 13. The upper part of the lifting plate 15 is rotatably fitted with a roller 14 corresponding to the cam 13, and the lower side is provided with a lifting column 16 corresponding to the heating frame 10. The lower end of the lifting column 16 extends into the heating chamber. A lifting cylinder 17 is installed on the lower end face of the lifting column 16. The lifting cylinder 17 slides in the heating chamber. An adjusting column 19 slides elastically inside the lifting cylinder 17. The lower end of the adjusting column 19 extends into the outside of the lifting cylinder 17. A cover plate 20 is installed on the lower end face of the adjusting column 19. A temperature sensor 21 is embedded in the lower side of the cover plate 20. The temperature sensor 21 is located above the corresponding heating frame 10. The heater 11, the temperature sensor 21, and the motor 12 are all electrically connected to the control console 5.

[0041] One application of this embodiment is as follows: When it is necessary to test the performance of the heat insulation coating, first use handle 3 to open the chamber door 2, then place the sample on the heating rack 10 with the side of the sample coated with the heat insulation coating facing down, then close the chamber door 2, and start the heater 11 through the control console 5 to heat up the sample. At this time, the control console 5 simultaneously starts the motor 12. The motor 12 drives the cam 13 to rotate at a certain angle. The cam 13 rotates and squeezes the roller 14 to make the lifting plate 15 slide down, thereby causing the lifting column 16 and the lifting cylinder 17 to descend. When the cover plate 20 contacts the sample surface, if the lifting cylinder 17 continues to move down, the adjusting column 19 can elastically retract into the lifting cylinder 17. Then the temperature sensor 21 monitors the sample surface temperature in real time and feeds it back to the control console 5. After the test is completed, the motor 12 reverses or continues to rotate to drive the cam 13 to reset, the lifting plate 15 moves up and resets under the action of elasticity, and the cover plate 20 is lifted away from the sample. After the heating chamber and the sample are quickly cooled by the cooling component, the chamber door 2 can be opened to take out the sample. It should be noted that all electrical devices involved in this application can be powered by batteries or external power sources.

[0042] By cooperating with the cam 13 and the roller 14, the friction between the cam 13 and the lifting plate 15 is reduced when the cam 13 is squeezed. At the same time, it is convenient for the motor 12 to work and control the lowering of multiple cover plates 20, so as to realize the simultaneous fixation and testing of multiple samples. The lifting plate 15 slides elastically, so that after the cam 13 is misaligned, the lifting plate 15 drives the roller 14 and the cover plate 20 to quickly reset. The adjusting column 19 slides elastically in the lifting cylinder 17, so that the cover plate 20 can adapt to the fixation requirements of heat insulation coatings or samples of different thicknesses. Thus, the device can test heat insulation coatings or samples of multiple thicknesses at the same time.

[0043] like Figure 2As shown, in this embodiment, a connecting rod is provided on one end face of the cam 13. The cam 13 is located between the motor 12 and the connecting rod. A bearing is installed around the connecting rod. A fixed cylinder is installed on one side of the inner wall of the fixed box 4. The fixed cylinder is installed around the bearing. The stability of the cam 13 when rotating is improved by the cooperation of the connecting rod and the fixed cylinder. The friction between the connecting rod and the fixed cylinder when rotating is reduced by the bearing.

[0044] like Figure 2 As shown, the upper side of the heating box 1 in this embodiment is provided with a slot corresponding to the lifting column 16. The slot is connected to the heating chamber, and the lifting column 16 passes through the slot. The slot reduces the probability of the heating box 1 obstructing the sliding of the lifting column 16.

[0045] like Figure 2 As shown, a U-shaped frame is installed on the upper side of the lifting plate 15 in this embodiment. A fixed rod is provided between the two sides of the inner wall of the U-shaped frame. The roller 14 is rotatably fitted around the fixed rod. The stability of the roller 14 when rotating is improved by the cooperation of the U-shaped frame and the connecting rod.

[0046] like Figure 2 As shown, in this embodiment, sliders are provided on both sides of the lifting plate 15, and grooves are provided on both sides of the inner wall of the fixed box 4. The sliders slide in the corresponding grooves. Multiple first springs 22 are installed between the lifting plate 15 and the upper side of the heating box 1. The first springs 22 are sleeved on the periphery of the corresponding lifting column 16. By cooperating with the sliders and grooves, the stability of the lifting plate 15 when sliding is improved. When the lifting plate 15 releases the pressure on the first springs 22, the first springs 22 facilitate the rapid reset of the lifting plate 15, thereby moving the cover plate 20 away from the heating frame 10.

[0047] like Figure 4 As shown, the lifting cylinder 17 of this embodiment is provided with a channel, and a lifting plate is slidably fitted in the channel. A second spring 18 is installed between the lifting plate and the upper end face of the channel. An adjusting column 19 is installed on the lower end face of the lifting plate. Through the cooperation of the lifting plate and the second spring 18, the adjusting column 19 can be elastically slid in the lifting cylinder 17, so that the cover plate 20 can be adapted to fix heat insulation coatings or samples of different thicknesses.

[0048] like Figure 1 As shown, the chamber door 2 in this embodiment is provided with an observation slot in the horizontal direction. The observation slot runs through the chamber door 2 and a transparent plate is installed inside the observation slot. A sealing strip corresponding to the heating chamber is installed on one side of the chamber door 2. The chamber door 2 is located between the sealing strip and the handle 3. The observation slot and the transparent plate work together to facilitate real-time observation of the test status of the sample in the heating chamber. At the same time, the sealing strip improves the sealing performance of the chamber door 2 in the heating chamber when it is closed, thereby improving the stability of the temperature in the heating chamber.

[0049] like Figure 2 , 3As shown, the cooling assembly of this embodiment includes a liquid nitrogen storage tank 6, a heating chamber 1 located between the liquid nitrogen storage tank 6 and the chamber door 2, a liquid nitrogen pump 7 installed on the liquid nitrogen storage tank 6, a liquid delivery pipe 8 connected to one side of the liquid nitrogen pump 7, a diffusion hood 9 installed on the back of the heating chamber 1, and the end of the liquid delivery pipe 8 away from the liquid nitrogen pump 7 connected to one side of the diffusion hood 9. The heating chamber has multiple through holes connected to the diffusion hood 9. Liquid nitrogen is stored in the liquid nitrogen storage tank 6, and the liquid nitrogen pump 7 draws out liquid nitrogen and delivers it to the diffusion hood 9 through the liquid delivery pipe 8. The diffusion hood 9 sprays the liquid nitrogen into the heating chamber, realizing rapid cooling of the heating chamber and the sample, thereby improving the efficiency of the device test. At the same time, the diffusion hood 9 and the multiple through holes work together to improve the uniformity of liquid nitrogen diffusion in the heating chamber.

[0050] This utility model is not limited to the above-described embodiments. Anyone should know that structural changes made under the guidance of this utility model, and any technical solutions that are the same as or similar to this utility model, fall within the protection scope of this utility model. Technical aspects, shapes, and structures not described in detail in this utility model are all publicly known technologies.

Claims

1. A device for testing the performance of thermal barrier coatings, characterized in that, include: A heating box (1) and a control console (5) are provided. The control console (5) is connected to one side of the heating box (1). The front of the heating box (1) is provided with a heating chamber and a door (2) corresponding to the heating chamber is hinged. A fixed box (4) is installed on the upper side of the heating box (1). A cooling component corresponding to the heating chamber is connected to the back of the heating box (1). Multiple heating racks (10) are installed on the lower side of the heating chamber. A heater (11) is installed inside the heating rack (10). An elastic compression component corresponding to the multiple heating racks (10) is installed inside the fixed box (4). The elastic compression assembly includes a motor (12) and a lifting plate (15). The motor (12) is installed on one side of the inner wall of the fixed box (4). The lifting plate (15) slides elastically in the fixed box (4). The output shaft of the motor (12) is fixedly connected to a cam (13). The upper part of the lifting plate (15) is rotatably fitted with a roller (14) corresponding to the cam (13). The lower side is provided with a lifting column (16) corresponding to the heating rack (10). The lower end of the lifting column (16) extends into the heating chamber. The lower end face of the lifting column (16) is equipped with a lifting cylinder (17). An adjusting column (19) slides elastically inside the lifting cylinder (17). The lower end of the adjusting column (19) extends into the outside of the lifting cylinder (17). The lower end face of the adjusting column (19) is equipped with a cover plate (20). The lower side of the cover plate (20) is embedded with a temperature sensor (21). The temperature sensor (21) corresponds to the control console (5).

2. The device for testing the performance of thermal barrier coatings according to claim 1, wherein, A connecting rod is provided on one end face of the cam (13), and a bearing is installed around the connecting rod. A fixing cylinder is installed on one side of the inner wall of the fixing box (4), and the fixing cylinder is installed around the bearing.

3. The heat insulation coating performance testing device according to claim 1, characterized in that, The upper side of the heating box (1) is provided with a slot corresponding to the lifting column (16), and the lifting column (16) passes through the slot.

4. The heat insulation coating performance testing device according to claim 1, characterized in that, A U-shaped frame is installed on the upper side of the lifting plate (15), and a fixed rod is provided between the two sides of the inner wall of the U-shaped frame. The roller (14) rotates and cooperates with the periphery of the fixed rod.

5. The thermal insulation coating performance testing device according to claim 1, characterized in that, The lifting plate (15) is equipped with sliders on both sides, and the inner wall of the fixed box (4) is equipped with grooves on both sides. The sliders slide in the corresponding grooves. Multiple first springs (22) are installed between the lifting plate (15) and the upper side of the heating box (1).

6. The thermal insulation coating performance testing device according to claim 1, characterized in that, The lifting cylinder (17) is provided with a channel, and a lifting plate is slidably fitted in the channel. A second spring (18) is installed between the lifting plate and the upper end face of the channel, and an adjusting column (19) is installed on the lower end face of the lifting plate.

7. The thermal insulation coating performance testing device according to claim 1, characterized in that, The door (2) is provided with a horizontal observation slot, and a transparent plate is installed inside the observation slot. A sealing strip corresponding to the heating chamber is installed on one side of the door (2).

8. The thermal insulation coating performance testing device according to claim 1, characterized in that, The cooling assembly includes a liquid nitrogen storage tank (6), a liquid nitrogen pump (7) is installed on the liquid nitrogen storage tank (6), a liquid delivery pipe (8) is connected to one side of the liquid nitrogen pump (7), a diffusion hood (9) is installed on the back of the heating chamber (1), the end of the liquid delivery pipe (8) away from the liquid nitrogen pump (7) is connected to one side of the diffusion hood (9), and a plurality of through holes connected to the diffusion hood (9) are provided on one side of the heating chamber.

Images