Measuring tube and specific surface area and pore size analyzer including the measuring tube

Abstract

This utility model relates to the technical field of specific surface area and pore size analysis equipment, specifically providing a measuring tube and a specific surface area and pore size analyzer including the measuring tube. It aims to solve the problem that existing measuring tubes, when measuring the saturated vapor pressure of adsorbate gases, experience unstable measurement results due to the increase in temperature and pressure within the measuring tube as the liquid level in the preset temperature environment decreases. To address this, the measuring tube of this utility model includes a body and an expansion section. The first end of the expansion section is closed, and the second end of the expansion section is connected to the first end of the body section, while the second end of the body section is open. The expansion section has a larger inner diameter than the body section. By providing the expansion section, the volume of the measuring tube immersed in the preset temperature environment can be increased, thereby improving the capacity to hold the adsorbate. As the liquid level in the preset temperature environment decreases and the ambient temperature increases, the adsorbate within the measuring tube is not affected by the increase in ambient temperature, ensuring stable temperature and pressure within the measuring tube and thus guaranteeing the accuracy of the measurement results.

Description

Technical Field

[0001] This utility model relates to the technical field of specific surface area and pore size analysis equipment, specifically providing a measuring tube and a specific surface area and pore size analyzer including the measuring tube. Background Technology

[0002] Currently, in the testing process of static volumetric surface area and pore size analyzers, it is necessary to test the saturated vapor pressure P0 of the adsorbate nitrogen gas in the current liquid nitrogen bath environment. The magnitude of this P0 value is of great value to the test results of the entire experiment.

[0003] In existing technologies, most methods use a measuring tube to measure the saturated vapor pressure P0 of the adsorbate nitrogen gas. When measuring the saturated vapor pressure P0 of nitrogen, the measuring tube is directly immersed in liquid nitrogen, placed in the same liquid nitrogen cup as the sample tube. The measuring tube is first evacuated, then filled with high-purity adsorbate gas nitrogen. As nitrogen is added, the pressure inside the measuring tube gradually increases. When saturation is reached, any further addition of nitrogen will liquefy, and the pressure inside the measuring tube will no longer increase with the addition of nitrogen. This saturated pressure is the saturated vapor pressure P0 of the adsorbate nitrogen gas at the current liquid nitrogen temperature environment.

[0004] Most existing measuring tubes are straight tubes. Due to the limited capacity of the measuring tube, as the liquid nitrogen in the liquid nitrogen cup evaporates, the liquid nitrogen level in the cup will drop, and the portion of the measuring tube immersed in the liquid nitrogen will decrease. The measuring tube will gradually be exposed to the outside of the liquid nitrogen environment. At this time, the temperature of the measuring tube exposed to the outside of the liquid nitrogen environment will rise, which will lead to an increase in the pressure inside the measuring tube. This will cause the measurement result of the saturated vapor pressure P0 to rise, resulting in unstable measurement results and deviations.

[0005] Therefore, a new technical solution is needed in this field to solve the above problems. Utility Model Content

[0006] The present invention aims to solve the above-mentioned technical problem, namely, to solve the problem that when measuring the saturated vapor pressure of adsorbate gas, the temperature and pressure inside the measuring tube increase as the liquid level in the preset temperature environment decreases, resulting in unstable measurement results.

[0007] In a first aspect, the present invention provides a measuring tube capable of measuring saturated vapor pressure. The measuring tube includes a body portion and an expansion portion distributed along its length. A first end of the expansion portion is closed, and a second end of the expansion portion communicates with the first end of the body portion. The second end of the body portion is open, wherein the inner diameter Φ2 of the expansion portion is greater than the inner diameter Φ1 of the body portion.

[0008] By adopting the above technical solution, this utility model can increase the volume of the measuring tube immersed in the preset temperature environment by setting an expansion part, thereby increasing the capacity of the measuring tube to hold adsorbate. As the liquid level in the preset temperature environment decreases and the ambient temperature of the measuring tube increases, the adsorbate in the measuring tube will not be affected by the increase in ambient temperature, thus stabilizing the temperature and pressure inside the measuring tube and ensuring the accuracy of the measurement results.

[0009] In the preferred embodiment of the above-mentioned measuring tube, the expansion portion is cylindrical and extends along the length direction of the measuring tube; and / or the inner diameter Φ2 of the expansion portion is between 2.4 mm and 4 mm.

[0010] By adopting the above technical solution, this utility model increases the volume and capacity of the expansion part by setting the inner diameter Φ2 of the expansion part between 2.4mm and 4mm, so that the adsorbate in the measuring tube will not be affected by the drop in liquid level in the preset temperature environment, thus ensuring the accuracy of the measurement; by setting the expansion part to a cylindrical shape, it is easy to process.

[0011] In the preferred embodiment of the above-mentioned measuring tube, the inner diameter Φ1 of the main body is between 0.8 mm and 1.2 mm.

[0012] By adopting the above technical solution, this utility model sets the inner diameter Φ1 of the main body between 0.8mm and 1.2mm, which makes it easy to process and safe to use.

[0013] In the preferred embodiment of the above-mentioned measuring tube, the dimension L1 of the expansion portion along the length direction of the measuring tube is between 15mm and 19mm; and / or the material of the measuring tube is stainless steel, titanium or aluminum.

[0014] By adopting the above technical solution, this utility model ensures the capacity of the expansion part by setting the length of the expansion part between 15mm and 19mm, which is reasonable and easy to process; by setting the material of the measuring tube to stainless steel, titanium or aluminum, it is sturdy and durable, and its service life is improved.

[0015] In the preferred embodiment of the above-mentioned measuring tube, the measuring tube further includes a heat-conducting part, which is sleeved on the outer wall of the main body and disposed near the expansion part.

[0016] By adopting the above technical solution, this utility model provides a heat-conducting part on the outer wall of the main body. When the liquid level in the preset temperature environment drops, the heat-conducting part is exposed first and can absorb the heat in the exposed environment. This avoids the rapid rise in temperature inside the measuring tube, which would lead to an increase in pressure inside the measuring tube and ensures the stability of the saturated vapor pressure measurement results.

[0017] In the preferred embodiment of the above-mentioned measuring tube, the distance d between the heat-conducting part and the expansion part is between 15 mm and 19 mm.

[0018] By adopting the above technical solution, this utility model sets the distance d between the heat-conducting part and the expansion part between 15mm and 19mm, and the structure is reasonably designed so that the heat-conducting part can absorb the heat in the exposed environment and ensure the normal temperature and pressure inside the measuring tube.

[0019] In the preferred embodiment of the above-mentioned measuring tube, the dimension L2 of the heat-conducting part along the length direction of the measuring tube is between 8 mm and 12 mm.

[0020] By adopting the above technical solution, this utility model increases the heat conduction area of ​​the heat conduction part and improves its heat conduction capacity by setting the length L2 of the heat conduction part between 8mm and 12mm.

[0021] In the preferred embodiment of the above-mentioned measuring tube, the heat-conducting part is made of stainless steel, titanium, or aluminum.

[0022] By adopting the above technical solution, this utility model makes it easier to process and produce by setting the material of the heat-conducting part to stainless steel, titanium or aluminum, the same as the material of the measuring tube.

[0023] In the preferred embodiment of the measuring tube described above, the wall thickness t of the measuring tube is 1 mm.

[0024] By adopting the above technical solution, this utility model sets the wall thickness t of the measuring tube to 1mm, which facilitates processing and production and improves the heat conduction capacity of the measuring tube.

[0025] In a second aspect, the present invention also provides a specific surface area and pore size analyzer, the specific surface area and pore size analyzer including the aforementioned measuring tube.

[0026] With the above technical solution adopted, the surface area and pore size analyzer of this utility model, by including the above-mentioned measuring tube, possesses the beneficial effects of the measuring tube. Compared with the previous surface area and pore size analyzer, the surface area and pore size analyzer of this utility model, by setting an expansion part at the first end of the measuring tube, can increase the volume of the measuring tube immersed in the preset temperature environment, thereby increasing the capacity of the measuring tube to hold adsorbate. As the liquid level in the preset temperature environment decreases and the ambient temperature of the measuring tube increases, the adsorbate in the measuring tube will not be affected by the increase in ambient temperature, thus stabilizing the temperature and pressure inside the measuring tube and ensuring the accuracy of the measurement results. Attached Figure Description

[0027] The preferred embodiments of this utility model are described below with reference to the accompanying drawings, in which:

[0028] Figure 1 This is a schematic diagram of the measuring tube of this utility model;

[0029] Figure 2 This is a cross-sectional view of the measuring tube of this utility model.

[0030] List of reference numerals in the attached diagram:

[0031] 1. Measuring tube; 11. Body; 12. Expansion section; 13. Heat-conducting section;

[0032] 2. Sample tubes;

[0033] 3. Liquid nitrogen cup. Detailed Implementation

[0034] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0035] It should be noted that in the description of this utility model, terms such as "top" and "bottom" that indicate direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this utility model.

[0036] Furthermore, it should be noted that in the description of this utility model, unless otherwise explicitly specified and limited, the terms "set," "connect," and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0037] As pointed out in the background art, existing measuring tubes, when measuring the saturated vapor pressure of adsorbate gases, experience unstable measurement results due to the increase in temperature and pressure inside the measuring tube as the liquid level in the preset temperature environment decreases. This invention provides a measuring tube for measuring saturated vapor pressure and a specific surface area and pore size analyzer including the measuring tube. The aim is to increase the volume of the measuring tube immersed in the preset temperature environment by setting an expansion section at the first end of the measuring tube, thereby increasing the capacity of the measuring tube to hold adsorbate. As the liquid level in the preset temperature environment decreases and the ambient temperature of the measuring tube increases, the adsorbate inside the measuring tube is not affected by the increase in ambient temperature, thus stabilizing the temperature and pressure inside the measuring tube and ensuring the accuracy of the measurement results.

[0038] Specifically, first refer to Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the measuring tube of this utility model. Figure 2 This is a cross-sectional view of the measuring tube of this utility model.

[0039] This invention provides a specific surface area and pore size analyzer, a precision instrument used to characterize the specific surface area and pore size distribution of material samples. Its core function lies in revealing the relationship between the microstructure and properties of materials by measuring the adsorption characteristics of gases on the material surface. The active surface and pore structure of catalysts significantly affect reaction rates; therefore, this instrument has important application value in materials science, chemical engineering, and other fields.

[0040] Saturated vapor pressure refers to the stable pressure of a vapor at a constant temperature when a liquid (or solid) and its vapor are in dynamic equilibrium. At this point, the number of molecules escaping from the liquid phase per unit time equals the number of molecules returning to the liquid phase, and the system is in thermodynamic equilibrium.

[0041] In specific surface area and pore size analysis, adsorbents are commonly used to measure the pore structure of materials. The adsorption process depends on the interaction between the adsorbent and the adsorbate, and saturated vapor pressure is a key parameter describing this interaction. At a given temperature, the saturated vapor pressure of the adsorbate (such as nitrogen) determines its distribution equilibrium between the gas and liquid (or solid) phases.

[0042] In specific surface area and pore size analysis, relative pressure (P / P0) is commonly used to describe the adsorption process, where P is the partial pressure of the adsorbate and P0 is the saturated vapor pressure of the adsorbate at the same temperature. The concept of relative pressure allows adsorption data from different materials to be compared within the same framework, thus enabling more accurate analysis of pore size distribution. Therefore, ensuring the accuracy and stability of the measured saturated vapor pressure of the adsorbate is crucial in specific surface area and pore size analysis.

[0043] The specific surface area and pore size analyzer of this invention, taking nitrogen as the adsorbate as an example, has the bottom ends of both the measuring tube 1 and the sample tube 2 immersed in a liquid nitrogen cup 3. The sample tube 2 contains the adsorbed sample to be tested. Taking liquid nitrogen as the preset temperature environment, the temperature of the liquid nitrogen in the liquid nitrogen cup 3 is 77.3K. During the test, the measuring tube 1 is first evacuated, and then filled with high-purity adsorbate gas nitrogen. As nitrogen is filled, the pressure inside the measuring tube 1 will gradually rise. When it reaches saturation, the nitrogen that is continuously filled will liquefy, and the pressure inside the measuring tube 1 will no longer rise with the filling of nitrogen. This saturated pressure is the saturated vapor pressure P0 of the adsorbate nitrogen at the current liquid nitrogen temperature environment of 77.3K. After the saturated vapor pressure P0 in the measuring tube 1 stabilizes, the sample tube 2 is filled with adsorbate gas nitrogen to test the adsorption amount of the adsorbed sample. By measuring the adsorption amount of adsorbate gas nitrogen under different pressures, an adsorption isotherm can be plotted. The shape of the adsorption isotherm provides information about the pore size distribution of the material. Variations in the saturated vapor pressure P0 directly affect the amount of adsorption, thus influencing the shape of the isotherm. Instability in the measurement of the saturated vapor pressure P0 can affect the accuracy of the analytical results.

[0044] like Figure 1 and Figure 2 As shown, the present invention also provides a measuring tube 1, which can be used to measure saturated vapor pressure. The measuring tube 1 includes a body portion 11 and an expansion portion 12 distributed along its length direction. The first end of the expansion portion 12 is closed, and the second end of the expansion portion 12 is connected to the first end of the body portion 11. The second end of the body portion 11 is open. The inner diameter Φ2 of the expansion portion 12 is larger than the inner diameter Φ1 of the body portion 11.

[0045] For example, such as Figure 1 and Figure 2As shown, the bottom ends of the measuring tube 1 and the sample tube 2 of this invention are both immersed in the liquid nitrogen cup 3. The preset temperature environment is a liquid nitrogen environment. Taking the liquid nitrogen temperature as an example, the specific surface area and pore size analyzer of this invention needs to measure the adsorption of gas by the sample in the sample tube 2 at a liquid nitrogen environment temperature of 77.3K. The first end of the expansion section 12 (which is the bottom end of the measuring tube 1 in the figure) is a closed end, and the second end of the body section 11 (which is the top end of the measuring tube 1 in the figure) is connected to the measuring instrument. The inner diameter Φ2 of the expansion section 12 is larger than the inner diameter Φ1 of the body section 11 of the measuring tube 1. The expansion section 12 is immersed in a preset temperature environment. By setting the expansion section 12 at the bottom end of the measuring tube 1, the volume of the measuring tube 1 immersed in liquid nitrogen can be increased, thereby increasing the capacity of the measuring tube 1 to hold liquid nitrogen. As the liquid nitrogen in the liquid nitrogen cup 3 evaporates, the liquid nitrogen level will slowly drop, and the external ambient temperature of the measuring tube 1 will rise. Since the measuring tube 1 is equipped with the expansion section 12, the liquid nitrogen in the measuring tube 1 will not be affected by the rise in the external ambient temperature, so that the temperature and pressure in the measuring tube 1 remain stable, thereby ensuring the accuracy of the measurement results.

[0046] It should be noted that this utility model does not limit the type of adsorbate. For example, those skilled in the art can also set the adsorbate as argon or carbon dioxide, etc. Such adjustments and changes to the specific type of adsorbate do not deviate from the principle and scope of this utility model and should be limited to the protection scope of this utility model.

[0047] Furthermore, it should be noted that this utility model does not limit the type of preset temperature environment. For example, those skilled in the art can also set the preset temperature environment to a liquid argon temperature environment of 87K or a carbon dioxide temperature environment of 195K, etc. Such adjustments and changes to the specific type of preset temperature environment do not deviate from the principle and scope of this utility model and should be limited to the protection scope of this utility model.

[0048] Furthermore, it should be noted that the present invention does not limit the shape of the expansion portion 12. For example, those skilled in the art can set the expansion portion 12 as a sphere, a cylinder, or an ellipsoid, etc. Such adjustments and changes to the specific shape of the expansion portion 12 do not deviate from the principle and scope of the present invention and should be limited to the protection scope of the present invention.

[0049] Preferably, such as Figure 1 and Figure 2 As shown, the expansion part 12 of this utility model is a cylindrical shape that extends along the length direction of the measuring tube 1.

[0050] Preferably, the inner diameter Φ2 of the expansion part 12 of this invention is between 2.4 mm and 4 mm.

[0051] For example, such as Figure 1 and Figure 2 As shown, the expansion part 12 of this utility model is cylindrical, and the inner diameter Φ2 of the expansion part 12 is larger than the inner diameter Φ1 of the main body part 11. For example, those skilled in the art can set the inner diameter Φ2 of the expansion part 12 to 2.4mm, 2.6mm, 2.8mm, 3.0mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, etc.

[0052] Of course, in this invention, the inner diameter Φ2 of the expansion part 12 is preferably set to 3.0mm.

[0053] Preferably, such as Figure 2 As shown, the inner diameter Φ1 of the body part 11 of the measuring tube 1 of this utility model is between 0.8mm and 1.2mm.

[0054] For example, those skilled in the art can set the inner diameter Φ1 of the body portion 11 of the measuring tube 1 to 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, etc.

[0055] Of course, in this utility model, the inner diameter Φ1 of the body part 11 of the measuring tube 1 is preferably set to 1.0mm.

[0056] Preferably, such as Figure 2 As shown, the dimension L1 of the expansion part 12 along the length direction of the measuring tube 1 of this utility model is between 15mm and 19mm.

[0057] For example, those skilled in the art can set the length L1 of the expansion portion 12 to 15mm, 16mm, 17mm, 18mm, 19mm, etc.

[0058] Of course, in this invention, the length L1 of the expansion portion 12 is preferably set to 17mm.

[0059] Preferably, the measuring tube 1 of this utility model is made of stainless steel, titanium or aluminum.

[0060] By making the measuring tube 1 the material of stainless steel, titanium or aluminum, it is sturdy and durable, and its service life is improved.

[0061] Preferably, such as Figure 1 and Figure 2 As shown, the measuring tube 1 of this utility model also includes a heat-conducting part 13, which is sleeved on the outer wall of the main body 11 and disposed near the expansion part 12.

[0062] For example, such as Figure 1 and Figure 2As shown, the measuring tube 1 of this invention has a heat-conducting part 13 sleeved above the expansion part 12. The heat-conducting part 13 is also immersed in the liquid nitrogen in the liquid nitrogen cup 3. By setting the heat-conducting part 13, the liquid nitrogen in the liquid nitrogen cup 3 can evaporate. When the liquid nitrogen level drops, the heat-conducting part 13 is first exposed to the outside of the liquid nitrogen environment, so that the external ambient temperature is first transferred to the heat-conducting part 13 and will not be directly transferred into the measuring tube 1, causing the temperature and pressure inside the measuring tube 1 to rise, thereby ensuring the stability of the saturated vapor pressure measurement.

[0063] Preferably, such as Figure 2 As shown, the distance d between the heat-conducting part 13 and the expansion part 12 of this utility model is between 15mm and 19mm.

[0064] For example, those skilled in the art can set the distance d between the heat-conducting part 13 and the expansion part 12 to 15mm, 16mm, 17mm, 18mm, 19mm, etc.

[0065] Of course, the present invention preferably sets the distance d between the heat-conducting part 13 and the expansion part 12 to 17mm.

[0066] Preferably, such as Figure 2 As shown, the dimension L2 of the heat-conducting part 13 along the length direction of the measuring tube 1 of this utility model is between 8mm and 12mm.

[0067] For example, those skilled in the art can set the length L2 of the heat-conducting part 13 to 8mm, 9mm, 10mm, 11mm, 12mm, etc.

[0068] Of course, in this invention, the length L2 of the heat-conducting part 13 is preferably set to 10mm.

[0069] Preferably, the heat-conducting part 13 of this utility model is made of stainless steel, titanium or aluminum.

[0070] For example, the present invention uses stainless steel as the material for the measuring tube 1 and the heat-conducting part 13, and they are integrally formed. This design facilitates processing and improves the service life of the measuring tube 1.

[0071] Preferably, such as Figure 2 As shown, the wall thickness t of the measuring tube 1 of this utility model is 1 mm.

[0072] By setting the wall thickness t of the body portion 11 of the measuring tube 1 to 1 mm, it is easier to process and produce, and the heat conduction capacity of the measuring tube 1 is improved.

[0073] Preferably, the wall thickness of the heat-conducting part 13 of this invention is also set to 1 mm.

[0074] Those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments in the claims of this application can be used in any combination.

[0075] The technical solution of this utility model has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the protection scope of this utility model is obviously not limited to these specific embodiments. Without departing from the principle of this utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this utility model.

Claims

1. A measuring tube, characterized in that, The measuring tube (1) is used to measure saturated vapor pressure. The measuring tube (1) includes a body part (11) and an expansion part (12) distributed along its length. The first end of the expansion part (12) is closed, and the second end of the expansion part (12) is connected to the first end of the body part (11). The second end of the body part (11) is open. The inner diameter Φ2 of the expansion part (12) is larger than the inner diameter Φ1 of the body part (11).

2. The measuring tube according to claim 1, characterized in that, The expansion portion (12) is cylindrical, extending along the length of the measuring tube (1); and / or The inner diameter Φ2 of the expansion part (12) is between 2.4 mm and 4 mm.

3. The measuring tube according to claim 2, characterized in that, The inner diameter Φ1 of the body part (11) is between 0.8 mm and 1.2 mm.

4. The measuring tube according to claim 1, characterized in that, The expansion portion (12) has a dimension L1 along the length of the measuring tube (1) between 15 mm and 19 mm; and / or The measuring tube (1) is made of stainless steel, titanium or aluminum.

5. The measuring tube according to claim 1, characterized in that, The measuring tube (1) also includes a heat-conducting part (13), which is sleeved on the outer wall of the main body (11) and disposed near the expansion part (12).

6. The measuring tube according to claim 5, characterized in that, The distance d between the heat-conducting part (13) and the expansion part (12) is between 15 mm and 19 mm.

7. The measuring tube according to claim 5, characterized in that, The dimension L2 of the heat-conducting part (13) along the length direction of the measuring tube (1) is between 8 mm and 12 mm.

8. The measuring tube according to claim 5, characterized in that, The heat-conducting part (13) is made of stainless steel, titanium or aluminum.

9. The measuring tube according to any one of claims 1 to 8, characterized in that, The wall thickness t of the measuring tube (1) is 1 mm.

10. A specific surface area and pore size analyzer, characterized in that, Includes the measuring tube (1) according to any one of claims 1 to 9.

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