An elemental analyzer and a detection method thereof

Abstract

The application discloses an element analyzer and a detection method thereof, and relates to the technical field of element analyzers.The element analyzer comprises a carrier gas gas circuit and a combustion oxygen supply gas circuit.The carrier gas gas circuit comprises a first gas source, a quantitative assembly and a detection unit.The combustion oxygen supply gas circuit comprises a second gas source, a combustion tube and a gas mixing tank assembly.The gas outlet side of the second gas source is in communication with one end of the combustion tube.The other end of the combustion tube is in communication with the gas inlet end of the gas mixing tank assembly.The gas mixing tank assembly comprises a tank body, a piston and a gas circuit control valve group.The piston is movably arranged in the tank body and can reciprocally move.The piston divides the tank body into an upper gas cavity and a lower gas cavity.The gas circuit control valve group is in communication with the upper gas cavity and the lower gas cavity through pipelines respectively.When the piston of the application ascends, the lower gas cavity collects sample gas.When the piston descends, the upper gas cavity collects sample gas.Only one-way movement of the piston is needed to complete sample gas collection for single sample testing, and there is no need for empty stroke return, so that the detection efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of elemental analyzer technology, and in particular to an elemental analyzer and its detection method. Background Technology

[0002] An elemental analyzer is a precision physicochemical analysis instrument based on the principles of high-temperature combustion decomposition, chromatographic separation, or thermal conductivity and infrared detection. It is primarily used for the quantitative determination of the mass percentage of five common organic elements—carbon, hydrogen, nitrogen, sulfur, and oxygen—in solid, liquid, and even some gaseous samples. The sample undergoes complete oxidative decomposition under high-purity oxygen atmosphere, transforming into gaseous products such as carbon dioxide, water, nitrogen, and sulfur dioxide. These products are then separated one by one through adsorption desorption and chromatographic column separation. Signal acquisition and conversion are performed using thermal conductivity and infrared detectors, rapidly outputting precise content data for each element.

[0003] Existing elemental analyzers use a gas switching valve between the oxygen and nitrogen gas paths to connect the carrier gas path with the hydrocarbon detection device. This, combined with a parallel conversion pipeline and nitrogen detection line, controls the gas flow and direction, thereby reducing gas leakage and unnecessary consumption of consumables such as copper particles and desiccants. However, the mixing tank of existing elemental analyzers can only collect sample gas in one direction, requiring a round trip to test a single sample, which affects testing efficiency. Summary of the Invention

[0004] The purpose of this application is to provide an elemental analyzer and its detection method, which solves the problem that the existing gas mixing tank can only collect sample gas in one direction, resulting in low testing efficiency.

[0005] To achieve the above objectives, this application provides an elemental analyzer, including: a carrier gas path and a combustion oxygen supply path;

[0006] The carrier gas path includes a first gas source, a metering component, and a detection unit. The metering component is connected to the output end of the first gas source, and the detection unit is located downstream of the metering component.

[0007] The combustion oxygen supply circuit includes a second gas source, a combustion pipe, and a mixing tank assembly. The outlet side of the second gas source is connected to one end of the combustion pipe, and the other end of the combustion pipe is connected to the inlet end of the mixing tank assembly. The mixing tank assembly includes a tank body, a piston, and a gas path control valve group. The piston is movably disposed in the tank body and can reciprocate. The piston divides the tank body into an upper gas chamber and a lower gas chamber. The gas path control valve group is connected to the upper gas chamber and the lower gas chamber through pipelines respectively. The gas path control valve group is used to control the air intake and exhaust states of the upper gas chamber and the lower gas chamber. The metering component is disposed downstream of the mixing tank assembly, and a main outlet valve is disposed downstream of the metering component.

[0008] In some embodiments, the detection unit includes a hydrogen-carbon infrared detection cell, a reduction furnace, a small purification tube, and a thermal conductivity cell. The hydrogen-carbon infrared detection cell is located downstream of the quantitative component. The reduction furnace and the small purification tube are connected in series in the downstream gas path of the hydrogen-carbon infrared detection cell to form a measurement branch. The measurement branch is connected in parallel with the output end of the quantitative component and connected to the input end of the thermal conductivity cell.

[0009] In some embodiments, the detection unit is further provided with a bypass branch, which is located downstream of the hydrogen-carbon infrared detection cell and the thermal conductivity cell, and the bypass branch is connected to the gas outlet side of the hydrogen-carbon infrared detection cell and the thermal conductivity cell, respectively.

[0010] In some embodiments, the carrier gas path is further provided with a carrier gas switching valve group, which is used to control the opening and closing of the reduction furnace, the small purification tube and the thermal conductivity tank.

[0011] In some embodiments, the carrier gas switching valve group includes a first valve, a second valve, a third valve, a fourth valve, and a fifth valve. The first valve is located on the outlet side of the first gas source, and a first connecting pipeline is provided between the outlet sides of the first gas source and the second gas source. The second valve is located on the first connecting pipeline. The third valve is located between the outlet side of the metering component and the input end of the thermal conductivity cell. The fourth valve is located on the outlet side of the hydrogen-carbon infrared detection cell, and the fifth valve is located on the outlet side of the bypass branch.

[0012] In some embodiments, the carrier gas path further includes a carrier gas supply unit, which is used to control the flow rate at the two input ends of the thermal conductivity pool.

[0013] In some embodiments, the carrier gas supply unit includes a pressure controller, a first pressure sensor, a first gas resistance, a second gas resistance, and a third gas resistance. The pressure controller and the first pressure sensor are connected in series between the first gas source and the metering component. The first gas resistance is located between the metering component and the thermal conductivity cell. The second gas resistance is located between the measurement branch and the thermal conductivity cell. The third gas resistance is located downstream of the hydrogen-carbon infrared detection cell and is connected in parallel with the measurement branch.

[0014] In some embodiments, the air circuit control valve group includes an upper air inlet valve, a lower air inlet valve, an upper air outlet valve, a lower air outlet valve, an upper pressure sensing control valve, a lower pressure sensing control valve, and a second pressure sensor. The upper air inlet valve is located on the air inlet side of the upper air chamber, the lower air inlet valve is located on the air inlet side of the lower air chamber, the upper air outlet valve and the lower air outlet valve are respectively located on the air outlet sides of the upper air chamber and the lower air chamber, a second connecting pipe is provided between the upper air chamber and the lower air chamber, and the upper pressure sensing control valve, the lower pressure sensing control valve and the second pressure sensor are connected in series in the second connecting pipe.

[0015] In some embodiments, the mixing tank assembly is further provided with a safety vent valve, and a safety vent is provided downstream of the safety vent valve.

[0016] An element detection method, applied to any of the element analyzers described above, includes the following steps:

[0017] The second gas source is started to supply oxygen to the combustion tube. The airflow flows along the pipeline and reaches the air intake side of the mixing tank assembly. The airflow enters the upper air chamber, the piston moves down until the upper air chamber reaches the set pressure, and then the upper air chamber is closed by the gas circuit control valve group and the lower air chamber is opened. The oxygen in the pipeline can pass through the lower air chamber and the metering component in sequence and be discharged from the exhaust main valve.

[0018] The sample is placed into the combustion tube, and oxygen is supplied to the combustion tube through the second gas source. The outlet side of the lower gas chamber is closed, and the sample gas enters the lower gas chamber until the lower gas chamber reaches the set pressure. At this time, the inlet side of the lower gas chamber is closed and the outlet side of the lower gas chamber is opened. The sample gas moves from the mixing tank to the metering component. After the pressure of the lower gas chamber drops to the set value, the exhaust valve is closed and the outlet side of the lower gas chamber is closed, sealing the metering component and the lower gas chamber.

[0019] The sample gas obtained from the quantitative component is switched to the carrier gas path. The first gas source fills the carrier gas path with helium. The sample gas flows to the detection unit with the helium and the detection unit detects the elemental content of the sample gas.

[0020] Compared to the aforementioned background technology, the elemental analyzer provided in this application embodiment includes a carrier gas path and a combustion oxygen supply path. The carrier gas path includes a first gas source, a metering component, and a detection unit. The metering component is connected to the output end of the first gas source, and the detection unit is located downstream of the metering component. The combustion oxygen supply path includes a second gas source, a combustion tube, and a mixing tank assembly. The outlet side of the second gas source is connected to one end of the combustion tube, and the other end of the combustion tube is connected to the inlet end of the mixing tank assembly. The mixing tank assembly includes a tank body, a piston, and a gas path control valve group. The piston is movably disposed within the tank body and can reciprocate. The piston divides the tank body into an upper gas chamber and a lower gas chamber. The gas path control valve group is connected to the upper gas chamber and the lower gas chamber through pipelines, respectively. The gas path control valve group is used to control the inlet and outlet states of the upper gas chamber and the lower gas chamber. The metering component is located downstream of the mixing tank assembly, and a main outlet valve is provided downstream of the metering component.

[0021] The first gas source provides high-purity helium as a carrier gas to deliver the sample gas from the quantitative component to the detection unit, which then performs elemental content detection on the sample gas carried by the carrier gas. The second gas source provides high-purity oxygen to supply oxygen to the combustion tube, a high-temperature combustion chamber where the sample is combusted at high temperature to form gaseous products that enter the mixing tank assembly. The quantitative component can extract the sample gas from the mixing tank assembly. The mixing tank assembly of the elemental analyzer in this application has a dual-chamber, bidirectional structure. When the piston moves upward, the lower gas chamber collects the sample gas; when the piston moves downward, the upper gas chamber collects the sample gas. For a single sample test, only a single piston movement is required to complete the sample gas collection, eliminating the need for a return stroke. This shortens the waiting time for single-sample testing, improves detection efficiency, and avoids the consumption of additional carrier gas during piston return, thus reducing the consumption of gas consumables. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the elemental analyzer according to an embodiment of this application;

[0024] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0025] in:

[0026] 1. First gas source; 2. Metering component; 31. Hydrogen-carbon infrared detection cell; 32. Reduction furnace; 33. Small purification tube; 34. Thermal conductivity cell; 41. First valve; 42. Second valve; 43. Third valve; 44. Fourth valve; 45. Fifth valve; 51. Pressure controller; 52. First pressure sensor; 53. First gas resistance; 54. Second gas resistance; 55. Third gas resistance; 6. Second gas source; 7. Combustion tube; 8. Mixing tank assembly; 91. Upper intake valve; 92. Lower intake valve; 93. Upper outlet valve; 94. Lower outlet valve; 95. Upper pressure sensor control valve; 96. Lower pressure sensor control valve; 97. Second pressure sensor; 10. Main outlet valve; 11. Mixing tank exhaust valve; 12. Safety exhaust valve. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] It should be noted that the directional terms such as "upper end," "lower end," "left side," and "right side" mentioned below are defined based on the accompanying drawings in the instruction manual.

[0030] like Figure 1 and Figure 2 As shown, the elemental analyzer provided in this application embodiment includes a carrier gas path and a combustion oxygen supply path. The carrier gas path includes a first gas source 1, a metering component 2, and a detection unit. The metering component 2 is connected to the output end of the first gas source 1. The detection unit is located downstream of the metering component 2. The combustion oxygen supply path includes a second gas source 6, a combustion pipe 7, and a mixing tank assembly 8. The outlet side of the second gas source 6 is connected to one end of the combustion pipe 7, and the other end of the combustion pipe 7 is connected to the inlet end of the mixing tank assembly 8. The mixing tank assembly 8 includes a tank body, a piston, and a gas path control valve group. The piston is movably disposed in the tank body and can reciprocate. The piston divides the tank body into an upper gas chamber and a lower gas chamber. The gas path control valve group is connected to the upper gas chamber and the lower gas chamber through pipelines respectively. The gas path control valve group is used to control the inlet and outlet states of the upper gas chamber and the lower gas chamber. The metering component 2 is located downstream of the mixing tank assembly 8, and a main outlet valve 10 is provided downstream of the metering component 2.

[0031] Specifically, the first gas source 1 provides high-purity helium as a carrier gas to deliver the sample gas from the quantitative component 2 into the detection unit, which is used to detect the elemental content of the sample gas carried by the carrier gas. The second gas source 6 provides high-purity oxygen to supply oxygen to the combustion tube 7, which is a high-temperature combustion chamber. The sample is burned at high temperature inside the tube to form gaseous products, which then enter the mixing tank assembly 8. The quantitative component 2 can extract the sample gas from the mixing tank assembly 8.

[0032] It is understood that the gas mixing tank assembly 8 in this embodiment of the application is a dual-chamber bidirectional structure. When the piston moves upward, the lower gas chamber collects the sample gas, and when the piston moves downward, the upper gas chamber collects the sample gas. For a single sample test, the sample gas collection can be completed by the piston moving in a single stroke, without the need for an empty stroke return. This shortens the waiting time for a single sample test, improves the detection efficiency, and avoids the consumption of additional carrier gas by the piston returning, thus reducing the amount of gas consumables used.

[0033] In some embodiments, the detection unit includes a hydrogen-carbon infrared detection cell 31, a reduction furnace 32, a small purification tube 33, and a thermal conductivity cell 34. The hydrogen-carbon infrared detection cell 31 is located downstream of the quantitative component 2. The reduction furnace 32 and the small purification tube 33 are connected in series in the downstream gas path of the hydrogen-carbon infrared detection cell 31 to form a measurement branch. The measurement branch is connected in parallel with the output end of the quantitative component 2 and connected to the input end of the thermal conductivity cell 34.

[0034] Understandably, the sample gas, along with the carrier gas, first enters the hydrogen-carbon infrared detection cell 31. Utilizing the characteristic absorption effect of carbon dioxide and water vapor on infrared light of specific wavelengths, the carbon and hydrogen content in the sample gas is quantitatively detected. After infrared detection, the sample gas enters the reduction furnace 32, where nitrogen oxides are reduced to elemental nitrogen. Then, it passes through a small purification tube 33 to remove interfering components such as carbon dioxide and water vapor, retaining only the nitrogen component. Finally, the thermal conductivity cell 34 utilizes the difference in thermal conductivity between nitrogen and the helium carrier gas to quantitatively detect the nitrogen content in the sample gas.

[0035] In some embodiments, the detection unit is further provided with a bypass branch, which is located downstream of the hydrogen-carbon infrared detection cell 31 and the thermal conductivity cell 34, and is connected to the gas outlet side of the hydrogen-carbon infrared detection cell 31 and the thermal conductivity cell 34, respectively.

[0036] It is understandable that the bypass branch serves as a common exhaust channel for the testing unit. After the test is completed, the exhaust gas can be discharged from the equipment through the bypass branch, eliminating the need to set up multiple independent exhaust ports and simplifying the gas path layout.

[0037] In some embodiments, the carrier gas path is further provided with a carrier gas switching valve group, which is used to control the opening and closing of the reduction furnace 32, the small purification pipe 33 and the heat conduction pool 34.

[0038] Understandably, when the test requires nitrogen detection, the carrier gas switching valve group opens the measurement branch, and the sample gas sequentially passes through the infrared cell, reduction furnace 32, and small purification tube 33 before entering the thermal conductivity cell 34 to complete the detection of all carbon, hydrogen, and nitrogen elements. When the test only requires the detection of carbon and hydrogen elements and the thermal conductivity cell 34 is not needed, the carrier gas switching valve group can cut off the measurement branch, keeping the reduction furnace 32, small purification tube 33, and thermal conductivity cell 34 in a closed state. This switching scheme can prevent gases such as oxygen, water vapor, and carbon dioxide from continuously flowing through the high-temperature reduction furnace 32 and thermal conductivity cell 34 in scenarios where thermal conductivity detection is not required, reducing the consumption of consumables such as copper particles and desiccants. At the same time, it prevents the cell body of thermal conductivity cell 34 from being affected by corrosive gases for a long time, thus avoiding performance degradation and effectively extending the service life of consumables in thermal conductivity cell 34 and reduction furnace 32, reducing equipment operation and maintenance costs.

[0039] Based on the above embodiments, the carrier gas switching valve group includes a first valve 41, a second valve 42, a third valve 43, a fourth valve 44, and a fifth valve 45. The first valve 41 is located on the outlet side of the first gas source 1, and a first connecting pipeline is provided between the outlet sides of the first gas source 1 and the second gas source 6. The second valve 42 is located on the first connecting pipeline. The third valve 43 is located between the outlet side of the metering component 2 and the input end of the thermal conductivity cell 34. The fourth valve 44 is located on the outlet side of the hydrogen-carbon infrared detection cell 31, and the fifth valve 45 is located on the outlet side of the bypass branch.

[0040] Specifically, the first valve 41 is connected in series on the main outlet pipe of the first gas source 1, and is used to control the overall on / off of the helium carrier gas. A first connecting pipe is provided between the outlet side of the first gas source 1 and the second gas source 6, and the second valve 42 is connected in series on the first connecting pipe, which can realize the switching access of oxygen from the second gas source 6 as the carrier gas. The third valve 43 is connected in series on the reference branch between the outlet side of the metering component 2 and the input end of the thermal conductivity cell 34, and controls the on / off of the reference branch. The fourth valve 44 is connected in series on the outlet side of the hydrogen-carbon infrared detection cell 31, and is used to switch the gas path downstream of the hydrogen-carbon infrared detection cell 31, connecting the measurement branch or the bypass branch. The fifth valve 45 is connected in series on the outlet side of the bypass branch, as the main exhaust control valve of the bypass branch.

[0041] It is understandable that by combining the opening and closing of the above five control valves, the two detection modes can be quickly switched. When the first valve 41, the third valve 43, and the fourth valve 44 are opened to conduct the measurement branch and the fifth valve 45 is used to exhaust the gas, it is the full element detection mode. In this mode, the sample gas passes through the infrared cell, the reduction furnace 32, and the purification tube in sequence before entering the thermal conductivity cell 34 to complete the detection of carbon, hydrogen, and nitrogen. When the second valve 42 is opened, the first valve 41 and the third valve 43 are closed, the fourth valve 44 is opened to conduct the bypass branch, and the fifth valve 45 is used to exhaust the gas, it is the simplified detection mode. The sample gas only passes through the hydrogen and carbon infrared detection cell 31. At this time, the reduction furnace 32, the small purification tube 33, and the thermal conductivity cell 34 are all in a closed state.

[0042] In some embodiments, the carrier gas path further includes a carrier gas supply unit, which is used to control the flow rate at the two input ends of the thermal conductivity cell 34.

[0043] Understandably, the thermal conductivity cell 34 has two input branches: a reference branch and a measurement branch. The carrier gas supply unit is used to precisely control the flow rate of the two branches to ensure flow rate matching between the reference side and the measurement side, thus providing stable airflow conditions for thermal conductivity detection.

[0044] Based on the above embodiments, the carrier gas supply unit includes a pressure controller 51, a first pressure sensor 52, a first air resistance 53, a second air resistance 54, and a third air resistance 55. The pressure controller 51 and the first pressure sensor 52 are connected in series between the first gas source 1 and the metering component 2. The first air resistance 53 is located between the metering component 2 and the thermal conductivity cell 34. The second air resistance 54 is located between the measurement branch and the thermal conductivity cell 34. The third air resistance 55 is located downstream of the hydrogen-carbon infrared detection cell 31 and is connected in parallel with the measurement branch.

[0045] Specifically, the pressure controller 51 and the first pressure sensor 52 are connected in series in the pipeline between the first gas source 1 and the metering component 2. The pressure controller 51 is used to regulate the carrier gas supply pressure, and the first pressure sensor 52 provides real-time feedback of the pipeline pressure, forming a pressure closed-loop control. The first gas resistance 53 is connected in series in the reference branch between the metering component 2 and the thermal conductivity cell 34 detector, forming a fixed gas resistance on the reference side. The second gas resistance 54 is connected in series between the measurement branch and the thermal conductivity cell 34 detector, forming a fixed gas resistance on the measurement side. The third gas resistance 55 is connected in series downstream of the hydrogen-carbon infrared detection cell 31, in parallel with the measurement branch, forming a fixed gas resistance in the simplified detection mode.

[0046] Understandably, since the orifice diameter of the fixed air resistance is constant, a stable flow rate can be output under the same air supply pressure. Therefore, the flow rate of each branch can be adjusted synchronously by simply adjusting the air supply pressure through the pressure controller 51. There is no need to configure an independent flow regulating valve and flow sensor for each branch, resulting in low hardware costs.

[0047] In some embodiments, the air circuit control valve group includes an upper air inlet valve 91, a lower air inlet valve 92, an upper air outlet valve 93, a lower air outlet valve 94, an upper pressure sensing control valve 95, a lower pressure sensing control valve 96, and a second pressure sensor 97. The upper air inlet valve 91 is located on the air inlet side of the upper air chamber, and the lower air inlet valve 92 is located on the air inlet side of the lower air chamber. A second connecting pipe is provided between the upper air chamber and the lower air chamber. The upper pressure sensing control valve 95, the lower pressure sensing control valve 96, and the second pressure sensor 97 are connected in series in the second connecting pipe.

[0048] Specifically, the upper intake valve 91 is connected in series on the intake side pipe of the upper air chamber, the lower intake valve 92 is connected in series on the intake side pipe of the lower air chamber, the upper exhaust valve 93 is connected in series on the exhaust side pipe of the upper air chamber, the lower exhaust valve 94 is connected in series on the exhaust side pipe of the lower air chamber, and a second connecting pipe is provided between the upper air chamber and the lower air chamber. The upper pressure sensing control valve 95, the lower pressure sensing control valve 96 and the second pressure sensor 97 are connected in series on this connecting pipe.

[0049] Understandably, the air intake and exhaust of the upper and lower air chambers are controlled by independent valves. By switching the opening and closing of the upper pressure sensing control valve 95 and the lower pressure sensing control valve 96, the pressure of the upper or lower air chamber can be detected by the second pressure sensor 97, which reduces the number of sensors and lowers the hardware cost.

[0050] In addition, a mixing tank exhaust valve 11 is provided downstream of the mixing tank assembly 8. When the mixing tank exhaust valve 11, the upper exhaust valve 93, and the lower exhaust valve 94 are opened, the gas in the mixing tank can be discharged through the pipeline via the mixing tank exhaust valve 11.

[0051] In some embodiments, the mixing tank assembly 8 is further provided with a safety vent valve 12, and a safety vent is provided downstream of the safety vent valve 12.

[0052] Specifically, the safety exhaust valve 12 is located on the air inlet side of the mixing tank assembly 8.

[0053] It is understandable that the safety exhaust valve 12 is a pressure overflow protection structure. When the gas pressure in the combustion oxygen supply circuit is greater than the normal value, the safety exhaust valve 12 can be opened to relieve pressure, ensure the safe operation of the equipment, and improve safety.

[0054] The element detection method provided in this application embodiment, applied to any of the above-mentioned element analyzers, includes the following steps:

[0055] The second gas source 6 is activated to supply oxygen to the combustion pipe 7. The airflow flows along the pipeline to the air inlet side of the mixing tank assembly 8. The upper air chamber is opened through the gas path control valve group. The oxygen enters the upper air chamber and pushes the piston downward until the pressure in the upper air chamber reaches the set value. Then the gas path control valve group closes the upper air chamber and opens the lower air chamber. The oxygen in the pipeline flows through the lower air chamber and the metering component 2, and is finally discharged from the main exhaust valve 10, completing the full purging of the combustion oxygen supply line and emptying the residual air and impurities in the pipeline.

[0056] The sample to be tested is placed into the combustion tube 7, and the second gas source 6 continuously supplies oxygen to completely burn and decompose the sample at high temperature. The generated sample gas flows to the mixing tank with the oxygen. At this time, the outlet side of the lower gas chamber is closed, and the sample gas enters the lower gas chamber and pushes the piston upward until the pressure of the lower gas chamber reaches the set value. Then, the inlet side of the lower gas chamber is closed and the outlet side of the lower gas chamber is opened. The mixed sample gas flows from the mixing tank to the quantitative component 2 for filling. After the pressure of the lower gas chamber drops to the set value, the main outlet valve 10 and the outlet side of the lower gas chamber are closed to complete the sealing of the quantitative component 2 and the lower gas chamber, thereby realizing quantitative gas sampling.

[0057] Switch the quantitative component 2 to the carrier gas path. The first gas source 1 introduces high-purity helium carrier gas into the carrier gas path. The sample gas to be tested in the quantitative component 2 flows into the detection unit along with the helium carrier gas. The detection unit sequentially completes the content detection of elements such as carbon, hydrogen, and nitrogen, and outputs the mass percentage data of the corresponding elements.

[0058] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0059] The elemental analyzer and its detection method provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the solution and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. An elemental analyzer, characterized in that, include: The carrier gas path includes a first gas source (1), a metering component (2), and a detection unit. The metering component (2) is connected to the output end of the first gas source (1), and the detection unit is located downstream of the metering component (2). The combustion oxygen supply circuit includes a second gas source (6), a combustion pipe (7), and a mixing tank assembly (8). The outlet side of the second gas source (6) is connected to one end of the combustion pipe (7), and the other end of the combustion pipe (7) is connected to the inlet end of the mixing tank assembly (8). The mixing tank assembly (8) includes a tank body, a piston, and a gas path control valve group. The piston is movably disposed in the tank body and can reciprocate. The piston divides the tank body into an upper gas chamber and a lower gas chamber. The gas path control valve group is connected to the upper gas chamber and the lower gas chamber through pipelines respectively. The gas path control valve group is used to control the inlet and outlet states of the upper gas chamber and the lower gas chamber. The metering component (2) is disposed downstream of the mixing tank assembly (8), and a main outlet valve (10) is provided downstream of the metering component (2).

2. The elemental analyzer according to claim 1, characterized in that, The detection unit includes a hydrogen-carbon infrared detection cell (31), a reduction furnace (32), a small purification tube (33), and a thermal conductivity cell (34). The hydrogen-carbon infrared detection cell (31) is located downstream of the quantitative component (2). The reduction furnace (32) and the small purification tube (33) are connected in series in the downstream gas path of the hydrogen-carbon infrared detection cell (31) to form a measurement branch. The measurement branch is connected in parallel with the output end of the quantitative component (2) to the input end of the thermal conductivity cell (34).

3. The elemental analyzer according to claim 2, characterized in that, The detection unit is also provided with a bypass branch, which is located downstream of the hydrogen-carbon infrared detection cell (31) and the thermal conductivity cell (34). The bypass branch is connected to the gas outlet side of the hydrogen-carbon infrared detection cell (31) and the thermal conductivity cell (34), respectively.

4. The elemental analyzer according to claim 3, characterized in that, The carrier gas path is also equipped with a carrier gas switching valve group, which is used to control the opening and closing of the reduction furnace (32), the small purification pipe (33) and the heat conduction pool (34).

5. The elemental analyzer according to claim 4, characterized in that, The carrier gas switching valve group includes a first valve (41), a second valve (42), a third valve (43), a fourth valve (44), and a fifth valve (45). The first valve (41) is located on the outlet side of the first gas source (1). A first connecting pipeline is provided between the outlet sides of the first gas source (1) and the second gas source (6). The second valve (42) is located on the first connecting pipeline. The third valve (43) is located between the outlet side of the metering component (2) and the input end of the thermal conductivity cell (34). The fourth valve (44) is located on the outlet side of the hydrogen-carbon infrared detection cell (31). The fifth valve (45) is located on the outlet side of the bypass branch.

6. The elemental analyzer according to claim 5, characterized in that, The carrier gas path also includes a carrier gas supply unit, which is used to control the flow rate at the two input ends of the thermal conductivity pool (34).

7. The elemental analyzer according to claim 6, characterized in that, The carrier gas supply unit includes a pressure controller (51), a first pressure sensor (52), a first gas resistance (53), a second gas resistance (54), and a third gas resistance (55). The pressure controller (51) and the first pressure sensor (52) are connected in series between the first gas source (1) and the metering component (2). The first gas resistance (53) is located between the metering component (2) and the thermal conductivity cell (34). The second gas resistance (54) is located between the measurement branch and the thermal conductivity cell (34). The third gas resistance (55) is located downstream of the hydrogen-carbon infrared detection cell (31) and is connected in parallel with the measurement branch.

8. The elemental analyzer according to claim 1, characterized in that, The air circuit control valve group includes an upper air inlet valve (91), a lower air inlet valve (92), an upper air outlet valve (93), a lower air outlet valve (94), an upper pressure sensing control valve (95), a lower pressure sensing control valve (96), and a second pressure sensor (97). The upper air inlet valve (91) is located on the air inlet side of the upper air chamber, and the lower air inlet valve (92) is located on the air inlet side of the lower air chamber. The upper air outlet valve (93) and the lower air outlet valve (94) are respectively located on the air outlet sides of the upper air chamber and the lower air chamber. A second connecting pipe is provided between the upper air chamber and the lower air chamber. The upper pressure sensing control valve (95), the lower pressure sensing control valve (96), and the second pressure sensor (97) are connected in series in the second connecting pipe.

9. The elemental analyzer according to claim 1, characterized in that, The mixing tank assembly (8) is also provided with a safety exhaust valve (12), and a safety vent is provided downstream of the safety exhaust valve (12).

10. An element detection method, applied to the elemental analyzer according to any one of claims 1-9, characterized in that, Includes the following steps: The second gas source (6) is started to supply oxygen to the combustion tube (7). The airflow flows along the pipeline and reaches the air intake side of the mixing tank assembly (8). The airflow enters the upper gas chamber, the piston moves down until the upper gas chamber reaches the set pressure, and then the upper gas chamber is closed by the gas circuit control valve group and the lower gas chamber is opened. The oxygen in the pipeline can pass through the lower gas chamber and the metering component (2) in sequence and be discharged from the exhaust main valve. The sample is placed into the combustion tube (7), and oxygen is supplied to the combustion tube (7) through the second gas source (6). The outlet side of the lower gas chamber is closed, and the sample gas enters the lower gas chamber until the lower gas chamber reaches the set pressure. At this time, the inlet side of the lower gas chamber is closed and the outlet side of the lower gas chamber is opened. The sample gas moves from the mixing tank to the metering component (2). After the pressure of the lower gas chamber drops to the set value, the exhaust valve is closed and the outlet side of the lower gas chamber is closed, sealing the metering component (2) and the lower gas chamber. The sample gas obtained by the quantitative component (2) is switched to the carrier gas path. The first gas source (1) fills the carrier gas path with helium. The sample gas flows to the detection unit with the helium and the detection unit detects the element content of the sample gas.

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