Residual oxygen eliminating system based on thermogravimetric analyzer

Abstract

According to the residual oxygen eliminating system based on the thermogravimetric analyzer, residual oxygen in a heating furnace body is eliminated in an inert gas purging and vacuumizing mode, the oxygen concentration in the furnace body is detected in real time, and a thermogravimetric experiment result in a real inert atmosphere is obtained. According to the utility model, a vacuum system, an oxygen concentration detection system and a pipeline connecting part are integrated into a whole, so that plug-and-play can be realized, and connection with thermogravimetric analyzers of different models can be realized. According to the utility model, not only can the concentration of residual oxygen in the inert atmosphere of the thermogravimetric analyzer be effectively reduced, but also the concentration of oxygen in the furnace body of the thermogravimetric analyzer can be monitored in real time. During an experiment, the starting time of the experiment can be conveniently determined according to the oxygen concentration, and meanwhile, a change curve of the oxygen concentration along with the time can be recorded in real time in the experiment process.

Description

Technical Field

[0001] The utility model belongs to the technical field of thermogravimetric analyzers, and in particular relates to a residual oxygen elimination system based on a thermogravimetric analyzer. Background Art

[0002] Thermogravimetric analysis technology refers to a thermal analysis technology that measures the relationship between the mass of a sample and temperature (or time) under program-controlled temperature. It is used to study mass changes related to decomposition, sublimation, adsorption, desorption, etc. Thermogravimetric analysis technology is a conventional analytical technology for material research and development and quality control. Existing commercial thermogravimetric analyzers can conduct experiments under dynamic and static atmospheres, which can meet most testing needs. In practical applications, some easily oxidized metals such as Fe, V, Zr, Ni, W and their low-valent compounds are prone to abnormal weight gain in an inert atmosphere, such as Figure 1 In addition, some carbon-containing compounds are also prone to abnormal weight loss due to oxidation under inert atmosphere. These abnormal mass changes are caused by residual oxygen in the heating furnace of the thermogravimetric analyzer. In experiments, an inert atmosphere purge device is usually used to purge for a long time to eliminate the residual oxygen, but the effect is not obvious. Figure 2 The TG curve of the iron powder sample obtained after purging with an inert atmosphere (flowing nitrogen) for 30 minutes is shown in FIG. Figure 2 It can be seen that there is still a significant mass increase above 300 °C, indicating that a short-term nitrogen purge through this device cannot completely eliminate the residual oxygen around the sample during the experiment. Utility Model Content

[0003] In order to solve the above technical problems, the utility model provides a residual oxygen elimination system based on a thermogravimetric analyzer, which eliminates the residual oxygen in the heating furnace body by simultaneously setting an inert gas purge device and a vacuum device, and detects the oxygen concentration in the furnace body in real time to obtain the thermogravimetric test results under a true inert atmosphere. The utility model integrates the vacuum system, oxygen concentration sensor and pipeline connection parts into one, which can be plug-and-play and connected to thermogravimetric analyzers of different models. This system can not only effectively reduce the concentration of residual oxygen in the inert atmosphere of the thermogravimetric analyzer, but also monitor the oxygen concentration in the furnace body of the thermogravimetric analyzer in real time. During the experiment, the start time of the experiment can be conveniently determined according to the oxygen concentration, and the change curve of the oxygen concentration over time can also be recorded in real time during the experiment.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A residual oxygen elimination system based on a thermogravimetric analyzer, comprising a solenoid valve assembly, an oxygen concentration detection system, and a vacuum system; the solenoid valve assembly comprises a power supply, a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, a fifth solenoid valve, a sixth solenoid valve, a seventh solenoid valve, a pressure control valve, and a pipeline connection part;

[0006] The power supply provides electricity for the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve, the sixth solenoid valve, the seventh solenoid valve, the oxygen concentration detection system and the vacuum system; the oxygen concentration detection system is used to measure the oxygen concentration in the furnace of the thermogravimetric analyzer; one end of the first solenoid valve is connected to the gas cylinder, and the other end is connected to one end of the second solenoid valve, one end of the pressure control valve and one end of the seventh solenoid valve through a four-way connection; the other end of the second solenoid valve is connected to the other end of the pressure control valve and one end of the third solenoid valve through a three-way connection; the other end of the third solenoid valve is connected to one end of the fourth solenoid valve, one end of the fifth solenoid valve and one end of the sixth solenoid valve through a four-way connection; the other end of the fourth solenoid valve is connected to the gas outlet of the thermogravimetric analyzer; the other end of the fifth solenoid valve is connected to the oxygen concentration detection system; the other end of the sixth solenoid valve is emptied and connected to the atmosphere; the other end of the seventh solenoid valve is connected to the vacuum pump.

[0007] Furthermore, a pressure gauge is arranged between the pressure control valve and the third solenoid valve.

[0008] Furthermore, the vacuum system, oxygen concentration detection system and pipeline connection parts are integrated into one, realizing plug-and-play, and can be connected to thermogravimetric analyzers of different models.

[0009] Beneficial effects:

[0010] 1. Easy to operate. It can be directly connected to a commercial thermogravimetric analyzer through an interface. After the power is turned on, the corresponding solenoid valves are opened in sequence to realize operations such as oxygen concentration monitoring and opening and closing of the vacuum system;

[0011] 2. Strong compatibility. The utility model can be directly connected to various types of thermogravimetric analyzers produced by different instrument manufacturers;

[0012] 3. The residual oxygen elimination effect is good. The sample did not show abnormal weight gain during the experiment, which is completely consistent with the theoretical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the thermogravimetric curve of iron powder under nitrogen conditions;

[0014] Figure 2 This is the thermogravimetric curve of iron powder after purging under nitrogen for 30 minutes;

[0015] Figure 3This is a composition diagram of a residual oxygen elimination system based on a thermogravimetric analyzer of the utility model;

[0016] Figure 4 This is the thermogravimetric curve of iron powder under nitrogen conditions after using the residual oxygen elimination system. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model. In addition, the technical features involved in each embodiment of the utility model described below can be combined with each other as long as they do not conflict with each other.

[0018] like Figure 3 As shown, a residual oxygen elimination system based on a thermogravimetric analyzer of the utility model includes a solenoid valve assembly, an oxygen concentration detection system, and a vacuum system. The solenoid valve assembly includes a power supply, a first solenoid valve 1, a second solenoid valve 2, a third solenoid valve 3, a fourth solenoid valve 4, a fifth solenoid valve 5, a sixth solenoid valve 6, a seventh solenoid valve 7, a pressure control valve, and a pipeline connection part.

[0019] The power supply mainly provides electricity for the first solenoid valve 1, the second solenoid valve 2, the third solenoid valve 3, the fourth solenoid valve 4, the fifth solenoid valve 5, the sixth solenoid valve 6, the seventh solenoid valve 7, the oxygen concentration detection system and the vacuum system; the oxygen concentration detection system is mainly used to measure the oxygen concentration in the furnace body of the thermogravimetric analyzer. Among them, one end of the first solenoid valve 1 is connected to the gas cylinder, and the other end is connected to one end of the second solenoid valve 2, one end of the pressure control valve PV and one end of the seventh solenoid valve 7 through a four-way connection; the other end of the second solenoid valve 2 is connected to the other end of the pressure control valve PV and one end of the third solenoid valve 3 through a three-way connection; a pressure gauge P is arranged between the pressure control valve PV and the third solenoid valve 3; the other end of the third solenoid valve 3 is connected to one end of the fourth solenoid valve 4, one end of the fifth solenoid valve 5 and one end of the sixth solenoid valve 6 through a four-way connection; the other end of the fourth solenoid valve 4 is connected to the gas outlet of the thermogravimetric analyzer TG; the other end of the fifth solenoid valve 5 is connected to the oxygen concentration detection system (O2 concentration measuring instrument); the other end of the sixth solenoid valve 6 is emptied and connected to the atmosphere; the other end of the seventh solenoid valve 7 is connected to the vacuum pump Vac.

[0020] During the experiment, first close the flow meter of the thermogravimetric analyzer, open the seventh solenoid valve 7, the third solenoid valve 3, and the fourth solenoid valve 4, and set the pumping rate of the pressure control valve PV at the same time to control the pumping rate to reach the set vacuum degree; if a lower vacuum is required, open the second solenoid valve 2 for rough pumping, and set the rough pumping conversion pressure. After reaching the target pressure, close the seventh solenoid valve 7, open the first solenoid valve 1 to backfill nitrogen to the target pressure. After closing all valves, open the flow meter of the thermogravimetric analyzer, open the fourth solenoid valve 4 and the fifth solenoid valve 5, and detect the oxygen concentration. If the oxygen concentration is lower than the set value, trigger the thermogravimetric experiment start button and the thermogravimetric experiment starts. If it is not reached, repeat the vacuum pumping and backfilling process until the experimental start conditions are met and the experiment starts. If the experimental atmosphere of the thermogravimetric experiment is air or there is no need to eliminate residual oxygen in the furnace, open the fourth solenoid valve 4 and the sixth solenoid valve 6, and the gas escaping from the thermogravimetric analyzer is emptied through the sixth solenoid valve 6.

[0021] like Figure 4 The figure shows the TG curve of iron powder in an inert atmosphere after the residual oxygen elimination system of the utility model is adopted. Figure 4 It can be seen that the sample did not show abnormal weight gain during the experiment, which is completely consistent with the theoretical value.

Claims

1. A residual oxygen elimination system based on a thermogravimetric analyzer, characterized in that: It includes a solenoid valve assembly, an oxygen concentration detection system, and a vacuum system; the solenoid valve assembly includes a power supply, a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, a fifth solenoid valve, a sixth solenoid valve, a seventh solenoid valve, a pressure control valve, and a pipeline connection part; The power supply provides electricity for the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve, the sixth solenoid valve, the seventh solenoid valve, the oxygen concentration detection system and the vacuum system; the oxygen concentration detection system is used to measure the oxygen concentration in the furnace of the thermogravimetric analyzer; one end of the first solenoid valve is connected to the gas cylinder, and the other end is connected to one end of the second solenoid valve, one end of the pressure control valve and one end of the seventh solenoid valve through a four-way connection; the other end of the second solenoid valve is connected to the other end of the pressure control valve and one end of the third solenoid valve through a three-way connection; the other end of the third solenoid valve is connected to one end of the fourth solenoid valve, one end of the fifth solenoid valve and one end of the sixth solenoid valve through a four-way connection; the other end of the fourth solenoid valve is connected to the gas outlet of the thermogravimetric analyzer; the other end of the fifth solenoid valve is connected to the oxygen concentration detection system; the other end of the sixth solenoid valve is emptied and connected to the atmosphere; the other end of the seventh solenoid valve is connected to the vacuum pump.

2. A residual oxygen elimination system based on a thermogravimetric analyzer according to claim 1, characterized in that: A pressure gauge is provided between the pressure control valve and the third solenoid valve.

3. The residual oxygen elimination system based on thermogravimetric analyzer according to claim 1, characterized in that: The vacuum system, oxygen concentration detection system and pipeline connection parts are integrated into one, which can be plug-and-play and can be connected to different models of thermogravimetric analyzers.

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