An evaporation boat with heat compensation function

Abstract

This invention discloses an evaporation boat with thermal compensation function, comprising a main body, an insulation layer, a phase change layer, and thermocouples. The main body is a split type, with the insulation layer surrounding it, and the phase change layer surrounding the insulation layer. The phase change layer is also split and correspondingly positioned to the main body, with thermocouples positioned outside the phase change layer. This patent aims to solve the problem of uneven temperature distribution in the evaporation boat caused by structural issues and varying heat dissipation at different locations along its length. By setting phase change layer segments with different specific heat capacities, and utilizing the differences in material properties of these segments, the temperature rise differs when different phase change layer segments absorb the same amount of heat, resulting in different temperature differences between them and the corresponding main body. This alters the heat dissipation rate of the corresponding main body, achieving a uniform temperature distribution of the material inside the main body.

Description

Technical Field

[0001] This evaporation boat relates to the field of vacuum coating, particularly to evaporation boat components in vacuum coating equipment. Background Technology

[0002] Evaporation boats, acting as carriers for evaporating materials, not only support the materials but also heat them. Uniform thermal evaporation of the material is essential for ensuring coating uniformity; uniform steam emission leads to a uniform coating, and the uniformity of the heat source guarantees uniform steam distribution. Similarly, the uniform heating of the evaporation boat, as the material carrier, ensures uniform steam distribution. Existing evaporation boats, due to limitations in heat source or structural design, commonly suffer from uneven heating, affecting the thermal evaporation of material steam. To address this issue, phase change materials (PCMs) are employed, offering multiple advantages: high energy efficiency, small size, the ability to store large amounts of energy, and minimal volume change during phase change. This makes them ideal for space-constrained applications. PCMs exhibit excellent cycle stability and long-term reliability, capable of withstanding multiple cycles without damage or failure. This makes them outstanding in applications requiring long-term use, such as solar energy storage systems and temperature control equipment. Furthermore, the phase change process of PCMs does not involve chemical reactions, thus producing no harmful gases or waste, making them environmentally friendly. Phase change materials (PCMs) can be designed with different phase change temperatures and heats to meet the needs of various applications. Furthermore, they can be regulated by controlling external conditions (such as pressure, temperature, and electric fields), exhibiting strong adjustability and controllability. By employing PCMs of various sizes, utilizing the large amount of heat absorbed during the phase change process, and adjusting the temperature, and by applying algorithms corresponding to materials with different melting points, the type and thickness of PCMs in the block structure can be controlled, and temperature control can be achieved through the properties of the PCMs. Summary of the Invention

[0003] To address the aforementioned problems, an evaporation boat with thermal compensation function is provided. The structure includes a main body, an insulation layer, a phase change layer, and thermocouples. The main body is a split type, surrounded by an insulation layer, and outside the insulation layer is a phase change layer, which is also split and correspondingly positioned to the main body. The thermocouples are located outside the phase change layer. The main body is made of high-temperature materials such as aluminum nitride, graphite, and aluminum boride. The insulation layer is made of high-temperature materials such as aluminum silicate fiber, ceramic fiber, silicon carbide, graphite, and zirconium oxide ceramic coating. The phase change layer is made of stearic acid, silver-tin alloy, sulfate, paraffin wax, bismuth, silver, and antimony phase change materials. The thermocouples are type B thermocouples made of platinum-rhodium alloy. Materials are filled within the main body, which serves as the evaporation heat source. The insulation layer provides thermal insulation properties. To reduce heat loss, the phase change layer possesses heat absorption and release properties. The evaporation boat also features thermal compensation: due to differences in material properties, each segment of the phase change layer experiences different temperature rises when absorbing the same amount of heat, resulting in varying temperature differences between it and the corresponding main body. This alters the heat dissipation rate of the main body, achieving a uniform temperature distribution within the main body. Furthermore, when the main body temperature decreases, it loses its thermal equilibrium, causing the corresponding phase change layer to absorb heat at a lower rate, thus suppressing a further decrease in the main body temperature. Conversely, when the main body temperature increases, it loses its thermal equilibrium, causing the corresponding phase change layer to absorb heat at a higher rate, thus suppressing a further increase in the main body temperature.

[0004] The insulation layer is tightly attached to the main body, with a gap of ≤0.1mm between them; the phase change layer is tightly attached to the insulation layer, with a gap of ≤0.05mm between them.

[0005] The main body is arranged in a linear, symmetrical distribution, with a quantity of ≥3 and increasing in odd numbers. The middle block has the lowest height, and the height of the other blocks increases symmetrically from the middle to both ends.

[0006] The insulation layer completely covers the outside of the main body and is higher than the height of the main body. It serves to insulate the main body, isolate the phase change layer from the main body, and prevent the phase change layer from becoming saturated due to excessively high main body temperature.

[0007] The phase change layer is set correspondingly to the main body. The phase change layer corresponding to the two main bodies at both ends is a single U-shaped structure, while the phase change layer corresponding to the other main bodies is a two-parallel structure. The height of the phase change layer is consistent with the height of the corresponding main body. The phase change layer is ensured to be flat and compacted. According to the characteristics of the phase change layer, it can undergo a phase change under temperature, pressure or other external stimuli, that is, it can change from one state of matter to another. Common phase changes include solid-liquid phase change and solid-gas phase change, and it has the following properties: high energy storage density, temperature stability, and fast response characteristics.

[0008] Based on the temperature characteristics of different sections of the main body, the specific heat capacity of the phase change layer is symmetrically decreased from the middle to both ends, while the thickness of the phase change layer is symmetrically increased. Since the heights of the main body sections differ, the insulation layer and phase change layer are set at the same height as the main body, surrounding its outer surface. In the initial state, due to structural factors, the heat dissipation differs, resulting in a higher temperature in the middle and lower temperatures on both sides during the vapor deposition process. Based on the characteristics of the phase change layer and its specific heat capacity, the phase change layer absorbs the same amount of heat with a smaller temperature change. The middle section has a higher temperature than the sides, requiring less insulation and corresponding to a smaller temperature change under a larger specific heat capacity. The outer phase change layer has a lower temperature and a smaller specific heat capacity, resulting in a larger temperature change after absorbing the same amount of heat, thus providing better insulation at a lower temperature. The proportional relationship between adjacent phase change layers is calculated using the shape, material, and specific heat capacity of different phase change layers, and the phase change layers are then set accordingly. The calculations are as follows: Q1 = c1ρ1V1(T2-T1), Q2 = c2ρ2V2(T3-T1), where Q1 is the heat absorbed by the phase change layer at the location with the larger specific heat capacity, c1 is the specific heat capacity at the same location, ρ1 is the density of the phase change layer at the same location, T2 is the corresponding main body temperature of the phase change layer at the same location, and T1 is the phase change layer temperature; Q2 is the heat absorbed by the phase change layer at the location with the smaller specific heat capacity, c2 is the specific heat capacity at the same location, ρ2 is the density of the phase change layer at the same location, and T3 is the corresponding main body temperature of the phase change layer at the same location. The phase change layers mentioned above are adjacent, and according to the setting requirements, c1 > c2 and Q1 > Q2. After conversion, the... After calculation, β is taken as 1.3 to 2.1. That is, according to the phase change layer setting method, adjacent phase change layers satisfy... Based on the principle that the heat flux from the main body to the insulation layer is equal to the heat flux from the insulation layer to the phase change layer, the thickness of the corresponding phase change layer is calculated and determined according to the temperature requirements of different sections of the main body. The calculation is as follows: q1 = q2, where q1 is the heat flux from the outer wall of the main body to the outer wall of the insulation layer, q2 is the heat flux from the outer wall of the insulation layer to the outer wall of the phase change layer, λ1 and λ2 are the thermal conductivity of the insulation layer and the phase change layer, respectively, T1, T2 and T3 are the temperatures of the main body, the insulation layer and the phase change layer, respectively, δ1 is the thickness of the insulation layer, and δ2 is the thickness of the phase change layer.

[0009] The heat generated at the main body is transferred to the phase change layer through the insulation layer. Different combinations of phase change layers with varying properties absorb heat and reach uniform temperature at different times. The specific time is determined by... Calculation, where ρ is the phase change layer density, c P Where K is the specific isobaric heat capacity of the phase change layer, and K is the thermal conductivity of the phase change layer. Let L be the heat absorbed by the phase change layer, L be the latent heat of phase change of the phase change layer, and α be the thermal conductivity of the phase change layer, taken as 10. -6 ~10 -5 m 2 Between / s, T l With T s , respectively, are the temperatures of the liquid and solid phases of the phase change layer, and n is a proportionality coefficient, ranging from 3 to 5.

[0010] For a given combination of phase change layers, the phase change layer density, specific isobaric heat capacity, thermal conductivity, latent heat of phase change, thermal conductivity, and the temperatures of the liquid and solid phases are all fixed values. The main body temperature is characterized by a proportionality coefficient. When the temperatures of each segment of the phase change layer are equal, the temperatures of the main body segments are equal. By comparing the time it takes for the temperatures of the main body segments to reach equality under different combinations of phase change layers, the optimal combination of phase change layers with the shortest time can be obtained. Attached Figure Description

[0011] Figure 1 This is a top view of the thermally compensated evaporation boat system, which includes the following 10 parts: Thermocouple 1, measuring the temperature at point 7 of phase change layer 1; Thermocouple 2, measuring the temperature at point 6 of phase change layer 2; Thermocouple 3, measuring the temperature at point 5 of phase change layer 3; Insulation layer 4, which provides insulation for the main body; Phase change layer 7, absorbing heat at point 10 of the main body; Phase change layer 6, absorbing heat at point 9 of the main body; Phase change layer 5, absorbing heat at point 8 of the main body.

[0012] Figure 2 This is a front sectional view of the thermally compensated evaporation boat system. Main body 1 (10), main body 2 (9), and main body 3 (8) serve to support and heat the materials.

[0013] The accompanying drawings are only used to illustrate the technical solution of the present invention, and the proportions of the parts in the drawings do not constitute a limitation on the present invention. Detailed Implementation

[0014] See Figure 1 Depending on the amount of phase change layer used, the height gradually increases from the inside to the outside, with the phase change layer height increasing sequentially from the inside to the outside, i.e., h7 < h6 < h5; the specific heat capacity of the material used in the phase change layer gradually decreases from the middle to both sides, i.e., c7 > c6 > c5.

[0015] This patent provides an evaporation boat with thermal compensation function. It has a symmetrical structure divided into four parts (the number of internal areas can be increased according to actual production needs, ≥3): a main body, an insulation layer, a phase change layer, and thermocouples. Materials are placed inside the main body, which is then connected to the outside by the insulation layer. The encapsulated phase change layer is tightly bonded to the insulation layer. A thermocouple is installed at the bottom of the phase change layer and connected by bolts. The main body is made of graphite and is heated by resistance evaporation, achieving the evaporation effect through electric heating. The insulation layer covers all four walls of the main body, with a gap of 0.06mm between them. The corners of the insulation layer are bent to increase adhesion. The phase change layer is tightly bonded to the insulation layer, with a gap of 0.03mm. The encapsulated phase change layer ensures flatness and compaction. Thermocouples offer advantages such as a wide temperature range, rapid response, good stability, strong corrosion resistance, low cost, simple structure, and immunity to external magnetic field interference. When using thermocouples for temperature measurement, they are securely connected to the middle of the connection line at the bottom of the phase change tank to ensure constant temperature measurement during phase change. The thermocouple is connected to the temperature gauge via wires, and all connections must be sealed with gaskets to prevent gas leakage.

[0016] Among them, the thermocouple is a type B platinum-rhodium 30-platinum-rhodium 6 thermocouple, and the insulation layer is made of aluminum silicate fiber, ceramic fiber, silicon carbide, graphite, and zirconium oxide ceramic coating, which serves to insulate the main body; phase change layer 1 7 is made of stearic acid and silver-tin alloy, which absorbs heat from the main body 1 10; phase change layer 2 6 is made of sulfate and paraffin, which absorbs heat from the main body 2 9; phase change layer 3 5 is made of bismuth, silver, and antimony, which absorbs heat from the main body 3 8.

[0017] Example

[0018] In this patent embodiment, according to the description, resistance thermal evaporation is used for coating. The setting method is set according to the materials and assembly method mentioned in the implementation. According to the setting requirements, the main body heating temperature is measured from left to right as 1323℃, 1451℃, 1543℃, 1389℃, and 1367℃. The heat insulation layer is made of ceramic fiber with a thickness of 30cm. The phase change layer is made of nitrate, stearic acid, paraffin, stearic acid, and nitrate respectively according to the arrangement.

[0019] Calculations showed that the thermocouples placed in phase change layers with thicknesses of 52cm, 20cm, 13cm, 20cm, and 52cm were 31℃, 29.5℃, and 33℃ respectively, ensuring a temperature difference within ±5%. The internal temperatures measured by the temperature gun were 1438℃, 1456℃, 1474℃, 1466℃, and 1454℃, with uniform temperature distribution. After 2 hours and 47 minutes, the temperature of the main body on the right side dropped to 1224℃, the thermocouple showed a temperature of 27℃ on the right side of the phase change tank, and the internal temperatures measured by the temperature gun were 1243℃, 1269℃, 1285℃, 1247℃, and 1224℃.

[0020] The thermal compensation function provided by this invention patent is achieved by adding a phase change layer. The traditional main body is only covered with a heat insulation layer without adding a phase change layer. Under the same conditions, the temperature of the traditional main body was measured by a temperature gun and the internal temperature was 1319℃, 1413℃, 1501℃, 1415℃ and 1314℃. The results show that compared with the traditional evaporation boat, the thermal compensation technology provided by this invention can better control the temperature and make it more uniformly distributed.

Claims

1. An evaporation boat with heat compensation function, characterized in that, The system comprises a main body, an insulation layer, a phase change layer, and thermocouples. The main body is a separate unit, surrounded by an insulation layer, which in turn is surrounded by a phase change layer. The phase change layer is also separate and corresponds to the main body. The thermocouples are located outside the phase change layer. The main body is made of aluminum nitride, graphite, and aluminum boride high-temperature materials. The insulation layer is made of aluminum silicate fiber, silicon carbide, graphite, and zirconia ceramic coating high-temperature materials. The phase change layer is made of stearic acid, silver-tin alloy, sulfate, paraffin wax, bismuth, silver, and antimony phase change materials. The thermocouples are type B thermocouples made of platinum-rhodium alloy. The materials are filled within the main body, which serves as the evaporative heat source. The insulation layer has… The thermal insulation properties reduce heat loss, and the phase change layer possesses heat absorption and release properties. The evaporation boat also features thermal compensation: due to differences in material properties, each segment of the phase change layer experiences different temperature rises when absorbing the same amount of heat, resulting in different temperature differences between it and the corresponding main body. This alters the heat dissipation rate of the corresponding main body, achieving a uniform temperature distribution within the main body. Furthermore, when the main body temperature decreases, it loses its thermal equilibrium state, causing the corresponding phase change layer to absorb less heat, thus suppressing a further decrease in the main body temperature. Conversely, when the main body temperature increases, it loses its thermal equilibrium state, causing the corresponding phase change layer to absorb more heat, thus suppressing a further increase in the main body temperature.

2. The evaporation boat with thermal compensation function according to claim 1, characterized in that, The insulation layer is tightly attached to the main body, with a gap of ≤0.1mm between them; the phase change layer is tightly attached to the insulation layer, with a gap of ≤0.05mm between them.

3. The evaporation boat with thermal compensation function according to claim 1, characterized in that, The main body has ≥3 blocks that increase in odd numbers, arranged in a linear fashion while maintaining a symmetrical distribution. The middle block has the lowest height, and the heights of the other blocks increase symmetrically from the middle to both ends.

4. The evaporation boat with thermal compensation function according to claim 1, characterized in that, The insulation layer completely covers the outside of the main body and is higher than the height of the main body. It serves to insulate the main body, isolate the phase change layer from the main body, and prevent the phase change layer from becoming saturated due to excessively high main body temperature.

5. The evaporation boat with thermal compensation function according to claim 1, characterized in that, The phase change layer is set in a corresponding manner to the main body. The phase change layer corresponding to the two main bodies at both ends is a single U-shaped structure, while the phase change layer corresponding to the other main bodies is a two-parallel structure. The height of the phase change layer is consistent with the height of the corresponding main body.

6. The evaporation boat with thermal compensation function according to claim 5, characterized in that, Based on the temperature of different sections of the main body, the specific heat capacity of the phase change layer is symmetrically decreased from the middle to both ends, and the thickness of the phase change layer is symmetrically increased.

7. The evaporation boat with thermal compensation function according to claim 6, characterized in that, The heat generated at the main body is transferred to the phase change layer through the insulation layer. Different combinations of phase change layers with varying properties absorb heat and reach uniform temperature at different times. The specific time is determined by... Calculation, where ρ is the phase change layer density, c P Where K is the specific isobaric heat capacity of the phase change layer, and K is the thermal conductivity of the phase change layer. The phase change layer absorbs heat, and L is the latent heat of phase change in the phase change layer. The thermal conductivity is the rate of change due to heat conduction, and α is the thermal conductivity of the phase change layer, taken as 10. -6 ~10 -5 m 2 Between / s, T l With T s , respectively, are the temperatures of the liquid and solid phases of the phase change layer, and n is a proportionality coefficient, ranging from 3 to 5.

8. The evaporation boat with thermal compensation function according to claim 7, characterized in that, For a given combination of phase change layers, the phase change layer density, specific isobaric heat capacity, thermal conductivity, latent heat of phase change, thermal conductivity, and the temperatures of the liquid and solid phases are all fixed values. The main body temperature is characterized by a proportionality coefficient. When the temperatures of each segment of the phase change layer are equal, the temperatures of the main body segments are equal. By comparing the time it takes for the temperatures of the main body segments to reach equality under different combinations of phase change layers, the optimal combination of phase change layers with the shortest time can be obtained.

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