Mixed gas conveying module for thermogravimetric analyzer

Abstract

The present invention discloses a thermogravimetric analyzer-oriented mixed gas conveying module, which comprises: at least two gas inlet pipes, one end of each gas inlet pipe being communicated with one end of a connecting pipe; a mixing assembly is installed in the mixing cylinder, the mixing cylinder is used for receiving gas exhausted by the connecting pipe and mixing the gas, the bottom of the mixing cylinder communicates with a gas outlet pipe, and the gas outlet pipe communicates with the TGA; an electromagnetic valve is arranged on one side of the mass flow controller, a proportional valve is arranged on the other side of the mass flow controller, and the proportional valve, the mass flow controller and the electromagnetic valve are sequentially connected with the air inlet pipe from near to far away from the connecting pipe. The proportional valve, the mass flow controller and the electromagnetic valve are connected with the gas inlet pipe from far to near, so that the effects of accurate flow adjustment, dynamic proportional control and rapid gas switching are achieved. Compared with the scheme of independently depending on manual switching or fixed premixed gas in the prior art, the problems that gas switching is slow and the proportion cannot be adjusted are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of thermogravimetric analysis, and in particular relates to a mixed gas delivery module for a thermogravimetric analyzer. Background Art

[0002] With the rapid development of materials science, Thermogravimetric Analysis (TGA) has been widely used as an important means to study the thermal properties of materials. TGA can measure the mass change of samples in a dynamic temperature environment, helping scientists evaluate the decomposition temperature, oxidation stability, adsorption, and desorption characteristics of materials. It is particularly important to test the thermogravimetric behavior of samples under different atmosphere conditions, because different gas environments will directly affect the thermochemical reaction process of materials. For example, tests in oxygen environments are often used for combustion performance analysis, while nitrogen or helium as inert gases are used to avoid oxidation of samples to ensure accurate capture of the thermal decomposition process of materials.

[0003] In traditional gas control systems, manual switching or mechanical gas path switching is often used to change the experimental atmosphere. This method not only requires manual intervention, but also causes time delays in switching. In dynamic experiments, especially those involving rapid atmosphere changes, this lag will interfere with the experimental results. The study of complex reaction dynamics will be greatly limited by the inability to quickly switch the atmosphere.

[0004] Many thermogravimetric analysis devices rely on premixed gas cylinders to provide mixed gases. However, the ratio of premixed gases is fixed and cannot be flexibly adjusted as needed during the experiment. When researchers need to dynamically change the gas ratio (such as a gradual change in oxygen concentration), the existing system is not up to the task. This limitation makes it very difficult to optimize conditions in studying high-temperature reactions or oxidation-reduction reactions.

[0005] At the same time, existing gas mixing modules mostly use simple straight-through pipelines or single mixing chamber structures, lacking optimized designs. Such designs are prone to uneven gas distribution when dealing with multiple gas mixtures. Especially when the gas flow rate is high or the proportions of multiple gas components vary greatly, uneven mixing will directly affect the stability of the experimental atmosphere, thereby reducing the reliability of the experimental data.

[0006] Finally, although many gas delivery systems have heating functions, they often rely on a single heating element to increase the gas temperature. This method cannot adjust the gas temperature in real time and in stages, and can easily cause local overheating or overcooling. Especially in long-term experiments, the instability of the gas flow temperature may interfere with the reaction process of the material and even affect the repeatability of the experimental results. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides a mixed gas delivery module for a thermogravimetric analyzer, which solves the problems in the prior art of slow and inflexible gas switching response, inability to adjust the gas mixing ratio in real time, poor uniformity of the mixed gas, and inaccurate gas temperature control.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: A mixed gas delivery module for a thermogravimetric analyzer, comprising: There are at least two air intake pipes, one end of the two air intake pipes is connected to one end of a connecting pipe.

[0009] The mixing cylinder is connected to the other end of the connecting pipe and has a mixing assembly installed inside for receiving and mixing the gas discharged from the connecting pipe. The bottom of the mixing cylinder is connected to an air outlet pipe, which is connected to the TGA.

[0010] The mass flow controller is provided with a solenoid valve on one side and a proportional valve on the other side, and the proportional valve, the mass flow controller and the solenoid valve are sequentially connected to the air intake pipe from near to far from the connecting pipe.

[0011] The present invention has the following beneficial effects: 1. The present invention achieves the effects of precise flow regulation, dynamic proportional control and rapid gas switching by connecting the proportional valve, mass flow controller and solenoid valve to the air intake pipe in order from far to near. Compared with the prior art solution that relies solely on manual switching or fixed premixed gas, it solves the problems of slow gas switching and unadjustable proportions.

[0012] 2. The present invention can effectively filter impurities in the gas by setting a two-stage filter assembly in the connecting pipe to ensure the purity of the gas entering the mixing cylinder. The problem that the impurity filtering treatment of the gas in the traditional technology is often single and easily leads to unstable quality of the mixed gas is solved. The present invention solves the problem that large particles and fine particles cannot be removed efficiently at the same time through the graded filter element design.

[0013] 3. The present invention can guide the airflow to move in a spiral path by using a splitter plate, a partition plate and a spiral guide strip, thereby increasing the turbulence effect of the gas and improving the mixing efficiency. The traditional technology mainly relies on a single structure when mixing gases, which is prone to uneven mixing. The multi-layer design of the present invention improves the mixing efficiency by guiding the airflow to flow in multiple directions, solving the problems of low efficiency and poor uniformity of traditional gas mixers.

[0014] 4. The present invention heats the gas temperature by arranging a heating tube on the outer wall of the mixing barrel and installing a temperature sensor inside. The temperature of the gas is controlled layer by layer to achieve precise temperature control. Compared with the prior art which simply relies on a single heating source and cannot adjust the temperature in real time, the segmented heating design of the present invention effectively solves the problem of unstable and uneven gas temperature control, and at the same time improves the reliability of experimental data. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention; Figure 2 It is a schematic diagram of the structure of the mixing barrel part of the present invention; Figure 3 It is a front cross-sectional view of the mixing barrel of the present invention; Figure 4 It is a schematic diagram of the structure of the guide plate part of the present invention; Figure 5 It is a partial structural schematic diagram of the diverter plate of the present invention.

[0016] Among them, 1. outer shell; 2. air inlet pipe; 3. connecting pipe; 4. filter assembly; 41. sleeve one; 42. filter element one; 43. sleeve two; 44. filter element two; 5. mixing cylinder; 6. heating assembly; 61. cover; 62. heating tube; 63. temperature sensor; 7. mixing assembly; 70. diverter plate; 71. partition; 72. guide plate; 73. pillar; 74. support plate; 75. guide strip; 76. guide wing; 8. outlet pipe; 9. pressure relief pipe; 10. pressure gauge; 11. pressure relief valve; 12. solenoid valve; 13. mass flow controller; 14. proportional valve. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In order to better understand the present invention, the above contents are described in detail below in conjunction with specific embodiments.

[0019] Please refer to the attached Figure 1 -Attached Figure 5The embodiment of the present application provides a mixed gas delivery module for a thermogravimetric analyzer, including: an air inlet pipe 2, of which at least two are provided, one end of the two air inlet pipes 2 is connected to one end of a connecting pipe 3; a mixing cylinder 5, which is connected to the connecting pipe 3 and has a mixing assembly 7 installed inside, for receiving the gas discharged from the connecting pipe 3 and mixing it, and an air outlet pipe 8 is connected to the bottom of the mixing cylinder 5, and the air outlet pipe 8 is connected to the TGA; a mass flow controller 13, a solenoid valve 12, and a proportional valve 14 are also provided on the air inlet pipe 2, and the proportional valve 14, the mass flow controller 13 and the solenoid valve 12 are connected to the air inlet pipe 2 in sequence from near to far from the connecting pipe 3.

[0020] In this embodiment, the air inlet pipe 2 can be used to guide the gas into the connecting pipe 3. Since at least two air inlet pipes 2 are provided, two or more gases can be guided to the connecting pipe 3 for preliminary mixing, and the gas passage can be opened or closed by the solenoid valve 12 to achieve selective gas delivery. The mass flow controller 13 can monitor and adjust the gas flow to ensure precise control of the flow rate. The proportional valve 14 is used to control the mixing ratio of each gas to achieve mixing of multiple gases. The gas can be further mixed by the mixing component 7 to ensure the uniformity of the gas mixing. After the mixing is completed, the gas is discharged from the outlet pipe 8.

[0021] A filter assembly 4 is installed inside the connecting pipe 3, and the filter assembly 4 includes a sleeve 1 41, a filter element 1 42, a sleeve 2 43 and a filter element 2 44. The filter element 2 44 is located in the sleeve 2 43, and the filter element 1 42 is located in the sleeve 1 41. The sleeve 1 41, the sleeve 2 43 and the connecting pipe 3 are interconnected. The sleeve 1 41 is close to the intake pipe 2, and the sleeve 2 43 is close to the mixing cylinder 5. The filter hole diameter of the filter element 1 42 is 20μm, and the filter hole diameter of the filter element 2 44 is 5μm.

[0022] In this embodiment, filter element 1 42 and filter element 2 44 are used to filter the gas twice, and the filter hole diameter of filter element 1 42 is smaller than the filter hole diameter of filter element 2 44. Therefore, filter element 1 42 can be used to perform preliminary filtration on impurities in the gas, and filter element 2 44 can further filter the impurities in the gas, thereby effectively preventing impurities or particles in the gas from entering the TGA.

[0023] The mixing assembly 7 includes a partition 71, a pillar 73 is fixedly connected to the middle of the top surface of the partition 71, a plurality of arc-shaped guide plates 72 are fixedly connected to the outside of the pillar 73, the bottoms of the plurality of guide plates 72 are fixedly connected to the top surface of the partition 71, one side of the partition 71 is fixedly connected to the inner top of the mixing barrel 5, the outer wall of the partition 71 is fixedly connected to a support plate 74, one side of the support plate 74 is fixedly connected to the inner top of the mixing barrel 5. The mixing assembly 7 also includes a diverter plate 70, the diverter plate 70 is fixedly connected to the middle of the top surface of the mixing barrel 5, and a plurality of through holes are provided in the middle of the diverter plate 70, so that the gas discharged from the connecting pipe 3 is divided into multiple air flows to enter the mixing barrel 5, and a guide wing 76 is fixedly connected to the bend of the inner wall of the gas outlet pipe 8. A guide strip 75 is fixedly connected to the middle of the inner wall of the mixing barrel 5, and the guide strip 75 is arranged in a spiral shape to guide the gas entering the mixing barrel 5 to move in a spiral path.

[0024] In this embodiment, when the gas enters the mixing barrel 5 from the connecting pipe 3, the gas will pass through the diverter plate 70. The through holes on the diverter plate 70 can be used to divide the airflow into multiple small airflows and impact on the partition 71. At this time, the arc-shaped guide plate 72 on the partition 71 can be used to guide the airflow to move in an arc shape and impact the inner wall of the mixing barrel 5 along the tangential direction of the inner wall of the mixing barrel 5. Subsequently, the airflow is guided by the spiral guide strip 75 to move in a spiral shape, thereby increasing the turbulent effect of the gas and improving the mixing efficiency. When the gas enters the outlet pipe 8 from the mixing barrel 5, the guide wing 76 can make the flow velocity and flow direction in the outlet pipe 8 more uniform, reduce the flow resistance of the gas, ensure that the mixed gas maintains the consistency of the composition and the stability of the flow velocity, and install the guide wing 76 at the curved pipe to cause turbulence in the gas, thereby improving the transportation efficiency and avoiding interference with the gas path of the thermogravimetric analyzer, further improving the accuracy and reliability of the experimental results.

[0025] The outer wall of the mixing barrel 5 is provided with a heating assembly 6, which includes a housing 61, which is fixedly connected to the outer wall of the mixing barrel 5, and a heating tube 62 is provided inside the housing 61, and a temperature sensor 63 is installed on the side wall of the inner wall of the mixing barrel 5. Multiple temperature sensors 63 and heating tubes 62 are provided.

[0026] In this embodiment, the mixing barrel 5 can be heated by the heating tube 62, and then the gas inside the mixing barrel 5 can be heated. The temperature sensor 63 can be used to detect the gas temperature to avoid the temperature being too high or too low. At the same time, multiple temperature sensors 63 and heating tubes 62 are distributed layer by layer in the mixing barrel 5. Therefore, when the temperature sensor 63 on the upper layer detects that the gas temperature is too high or too low, the heating tube 62 on the lower layer can be controlled to reduce or increase the power, so as to ensure that the gas temperature meets the requirements, which is beneficial to the accuracy and reliability of the experimental results.

[0027] A pressure relief pipe 9 is fixedly connected to the bottom of the mixing barrel 5, a pressure relief valve 11 is installed on one side of the pressure relief pipe 9, and a pressure gauge 10 is installed in the middle of the pressure relief pipe 9. The outside of the air inlet pipe 2 is fixedly connected to the housing 1, and the air outlet pipe 8, the pressure relief pipe 9 and the connecting pipe 3 are all located inside the housing 1. A controller is also installed inside the housing 1, and a communication interface is provided on one side of the controller for connecting with the TGA through a wiring harness.

[0028] In this embodiment, the pressure in the mixing cylinder 5 and the pressure relief pipe 9 can be detected by the pressure gauge 10. When the pressure is too high, the pressure relief valve 11 can be opened to discharge the gas, thereby ensuring the safety of the operation of the device, and the controller is connected to each valve and component, so that the information of each valve and sensor can be monitored and displayed in real time, thereby realizing the effect of remote monitoring and adjustment of gas parameters.

[0029] Working principle: When in use, the gas enters the connecting pipe 3 through the air inlet pipe 2, then enters the mixing cylinder 5 and is discharged from the air outlet pipe 8, and finally enters the TGA.

[0030] At this time, the entrance of each intake pipe 2 is controlled by the solenoid valve 12, so the flow path of the corresponding gas can be selectively opened or closed to prevent gas leakage in the non-working state; and after the gas enters the intake pipe 2 and passes through the solenoid valve 12, it will pass through the mass flow controller 13 and the proportional valve 14 in turn. The mass flow controller 13 can monitor and accurately adjust the flow rate of each gas in real time, and the proportional valve 14 can adjust the flow rate of each gas according to the set mixing ratio to ensure that the ratio of the mixed gas meets the experimental requirements.

[0031] Subsequently, the gas is discharged from the air inlet pipe 2 into the connecting pipe 3. At this time, the gas will successively pass through the sleeve 1 41 and the sleeve 2 43 in the filter assembly 4. When passing through the sleeve 1 41, the filter element 1 42 can perform preliminary filtration on the gas to intercept larger particle impurities. When passing through the filter element 2 44, since the pore size of the filter element 2 44 is smaller than the pore size of the filter element 1 42, the fine particle impurities can be further filtered, thereby ensuring the purity of the gas entering the mixing cylinder 5.

[0032] After being discharged from the connecting pipe 3, the gas enters the mixing barrel 5 for mixing. There are two air inlet pipes 2 and only one connecting pipe 3. Therefore, the gas in the two air inlet pipes 2 will be preliminarily mixed after entering one connecting pipe 3. A diverter plate 70 is installed on the top of the mixing barrel 5. The diverter plate 70 can be used to divide an airflow into multiple airflows. Then the multiple airflows will impact the partition 71. At this time, the partition 71 will guide the multiple airflows to blow toward the side wall inside the mixing barrel 5. The guide plate 72 is set to an arc shape. Therefore, under the guidance of the guide plate 72, the airflow will blow obliquely toward the side wall of the inner wall of the mixing barrel 5, and then follow the guide strip 75, using its spiral structure to guide the airflow to move in a spiral path, thereby increasing the turbulent effect of the gas and improving the mixing efficiency.

[0033] When the gas enters the mixing barrel 5, the mixing barrel 5 can be heated by driving the heating tube 62, and then the gas entering the mixing barrel 5 can be heated. The temperature of the gas can be monitored in real time by the temperature sensor 63 to avoid the temperature of the airflow being too high or too low. A plurality of heating tubes 62 and temperature sensors 63 are installed on the mixing barrel 5 in sequence from top to bottom, and a temperature sensor and a heating tube 62 are layered corresponding to each other. Therefore, the heating tube 62 on the upper layer of the mixing barrel 5 can preliminarily heat the gas. After the temperature of the airflow is detected by the temperature sensor 63 on the upper layer, the preliminary temperature of the airflow can be obtained. When the temperature is too low, the heating tube 62 on the next layer is driven to increase the heating power. When the temperature is too high, the heating tube 62 on the next layer is driven to reduce the heating power, thereby ensuring the accuracy of the airflow temperature.

[0034] When the heating of the gas is completed, the gas is discharged from the bottom of the mixing barrel 5 and guided by the guide wings 76. The guide wings 76 can be used to optimize the gas flow path, so that the flow rate and flow direction of the gas in the outlet pipe 8 are more uniform, thereby effectively reducing the flow resistance of the gas, while ensuring that the consistency of the components and the stability of the flow rate of the mixed gas are maintained during the transportation process. By installing the guide wings 76 at the curved pipe, the gas can generate turbulence, thereby improving the transportation efficiency and avoiding interference with the gas path of the thermogravimetric analyzer, so that when the gas enters the sample chamber of the thermogravimetric analyzer, it can provide a more stable and uniform purge or reaction atmosphere, further improving the accuracy and reliability of the experimental results.

[0035] Since the pressure relief pipe 9 is connected to the mixing barrel 5, the airflow inside the mixing barrel 5 will also enter the pressure relief pipe 9. At this time, the pressure gauge 10 can be used to detect the pressure inside the pressure relief pipe 9 and the mixing barrel 5. When the pressure is too high, the gas inside the pressure relief pipe 9 can be discharged by opening the pressure relief valve 11, thereby avoiding excessive pressure inside the mixing barrel 5, thereby improving the safety of the device when used.

[0036] At the same time, a controller is also installed inside the housing 1, and the controller is connected to the heating tube 62, the temperature sensor 63, the pressure gauge 10, the pressure relief valve 11, the solenoid valve 12, the mass flow sensor and the proportional valve 14, so that the gas parameters can be remotely monitored and adjusted.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A mixed gas delivery module for a thermogravimetric analyzer, characterized in that: include: Inlet pipes (2), at least two of which are provided, one end of the two inlet pipes (2) being connected to one end of a connecting pipe (3); A mixing cylinder (5) which is in communication with the other end of the connecting pipe (3) and has a mixing assembly (7) installed therein for receiving and mixing the gas discharged from the connecting pipe (3); a gas outlet pipe (8) is in communication with the bottom of the mixing cylinder (5); and the gas outlet pipe (8) is in communication with the thermogravimetric analyzer; A mass flow controller (13) is provided with a solenoid valve (12) on one side and a proportional valve (14) on the other side, and the proportional valve (14), the mass flow controller (13) and the solenoid valve (12) are connected to the air intake pipe (2) in order from near to far from the connecting pipe (3).

2. A mixed gas delivery module for a thermogravimetric analyzer according to claim 1, characterized in that: A filter assembly (4) is installed inside the connecting pipe (3), and the filter assembly (4) comprises a sleeve 1 (41), a filter element 1 (42), a sleeve 2 (43) and a filter element 2 (44); The second filter element (44) is located in the second sleeve (43), the first filter element (42) is located in the first sleeve (41), and the first sleeve (41), the second sleeve (43) and the connecting pipe (3) are interconnected. The first sleeve (41) is close to the air inlet pipe (2), and the second sleeve (43) is close to the mixing cylinder (5).

3. A mixed gas delivery module for a thermogravimetric analyzer according to claim 2, characterized in that: The pore diameter of the filter element 1 (42) is 20µm, and the pore diameter of the filter element 2 (44) is 5µm.

4. A mixed gas delivery module for a thermogravimetric analyzer according to claim 1, characterized in that: The mixing assembly (7) comprises a partition (71), a pillar (73) is fixedly connected to the middle of the top surface of the partition (71), a plurality of arc-shaped guide plates (72) are fixedly connected to the outside of the pillar (73), the bottoms of the plurality of guide plates (72) are fixedly connected to the top surface of the partition (71), a support plate (74) is fixedly connected to the outer wall of the partition (71), and one side of the support plate (74) is fixedly connected to the inner top of the mixing barrel (5).

5. A mixed gas delivery module for a thermogravimetric analyzer according to claim 4, characterized in that: The mixing assembly (7) further comprises a flow divider plate (70), the flow divider plate (70) being fixedly connected to the middle portion of the top surface of the mixing barrel (5), and a plurality of through holes being provided in the middle portion of the flow divider plate (70), so that the gas discharged from the connecting pipe (3) is divided into a plurality of gas streams and enters the mixing barrel (5), and a flow guide wing (76) is fixedly connected to the bend of the inner wall of the gas outlet pipe (8).

6. A mixed gas delivery module for a thermogravimetric analyzer according to claim 4 or 5, characterized in that: A guide strip (75) is fixedly connected to the middle of the inner wall of the mixing cylinder (5), and the guide strip (75) is arranged in a spiral shape and is used to guide the gas entering the interior of the mixing cylinder (5) to move in a spiral path.

7. A mixed gas delivery module for a thermogravimetric analyzer according to claim 6, characterized in that: The outer wall of the mixing barrel (5) is provided with a heating component (6), the heating component (6) comprises a cover shell (61), the cover shell (61) is fixedly connected to the outer wall of the mixing barrel (5), a heating tube (62) is provided inside the cover shell (61), and a temperature sensor (63) is installed on the side wall of the inner wall of the mixing barrel (5).

8. The mixed gas delivery module for thermogravimetric analyzer according to claim 7, characterized in that: A plurality of the temperature sensors (63) and the heating tubes (62) are provided, and the plurality of temperature sensors (63) and the heating tubes (62) are distributed layer by layer in the mixing barrel (5).

9. The mixed gas delivery module for thermogravimetric analyzer according to claim 1, characterized in that: A pressure relief pipe (9) is fixedly connected to the bottom of the mixing cylinder (5), a pressure relief valve (11) is installed on one side of the pressure relief pipe (9), and a pressure gauge (10) is installed in the middle of the pressure relief pipe (9).

10. A mixed gas delivery module for a thermogravimetric analyzer according to claim 9, characterized in that: The outside of the air inlet pipe (2) is fixedly connected to the housing (1), the air outlet pipe (8), the pressure relief pipe (9) and the connecting pipe (3) are all located inside the housing (1), and a controller is also installed inside the housing (1), one side of which is provided with a communication interface for connecting to the thermogravimetric analyzer via a wiring harness.

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