Time-division multiplexing multi-component combustible gas concentration measuring device and measurement method

Abstract

This invention relates to the field of explosion-proof product testing technology, and particularly to a time-division multiplexing multi-component combustible gas concentration measuring device and method. The device includes at least three inlet pipes, at least three measuring pipes, and an oxygen concentration sensor. The at least three inlet pipes and at least three measuring pipes correspond to each other. The at least three measuring pipes include a first measuring pipe, a second measuring pipe, and a third measuring pipe. By opening the first, second, and third measuring pipes at different time periods, the oxygen concentration sensor is time-division multiplexed to obtain the oxygen concentration in the three measuring pipes. Based on the oxygen concentration in the three measuring pipes, the concentrations of the first and second combustible gases are calculated. This invention's measuring device and method, using only one oxygen concentration sensor, can measure the concentrations of oxygen, the first combustible gas, and the second combustible gas in a ternary gas mixture, reducing equipment costs and daily maintenance costs.

Description

Technical Field

[0001] This invention relates to the field of explosion-proof product testing technology, and in particular to a time-division multiplexing multi-component combustible gas concentration measuring device and measuring method. Background Technology

[0002] Explosion-proof performance testing of explosion-proof products, such as reference pressure measurement, pressure resistance test, and non-explosion propagation test under internal ignition, is one of the main tests specified in GB / T 3836.2-2021. The test process requires the configuration and measurement of explosive mixtures of specific concentrations, such as an explosive mixture of methane and hydrogen with a volume ratio of (12.5±0.5)% methane to air [(58±1)% methane and (42±1)% hydrogen]. To measure the individual concentrations of methane and hydrogen in the explosive mixture, existing test equipment is equipped with one methane concentration sensor and one hydrogen concentration sensor to directly measure the concentration, or with one oxygen concentration sensor and one methane concentration sensor or one hydrogen concentration sensor. The number of gas concentration sensors installed is no less than two, resulting in high equipment costs. The daily calibration and maintenance costs of the gas concentration analyzer are also relatively high. Summary of the Invention

[0003] The technical problem this invention aims to solve is the high cost of existing equipment and the relatively high costs of routine calibration and maintenance of gas concentration analyzers. This invention provides a time-division multiplexing multi-component combustible gas concentration measuring device and method. Using a single oxygen concentration sensor, it can measure the concentrations of oxygen, the first combustible gas, and the second combustible gas in a ternary gas mixture, reducing the manufacturing and routine maintenance costs of the testing equipment. The technical solution adopted by this invention to solve its technical problem is: a time-division multiplexing multi-component combustible gas concentration measuring device, comprising:

[0004] At least three air intake lines are provided, namely one air intake line and at least two combustible gas intake lines. The two combustible gas intake lines include a first combustible gas intake line and a second combustible gas intake line. A first mixer is provided between the air intake line and the first combustible gas line to mix air and the first combustible gas. A second mixer is provided between the first mixer and the second combustible gas intake line to mix air, the first combustible gas and the second combustible gas.

[0005] At least three measuring lines are provided, including at least three air intake lines and at least three corresponding measuring lines, including a first measuring line, a second measuring line and a third measuring line. One end of the first measuring line is provided on the air intake line and located at the front end of the first mixer. One end of the second measuring line is provided between the first mixer and the second mixer. One end of the third measuring line is provided at the rear end of the second mixer.

[0006] An oxygen concentration sensor is provided, with the other ends of the first measuring line, the second measuring line, and the third measuring line all connected to the oxygen concentration sensor. By opening the first, second, and third measuring lines at different time periods, the oxygen concentration sensor is time-division multiplexed to obtain the oxygen concentration in the three measuring lines. The concentrations of the first and second combustible gases are then calculated based on the oxygen concentrations in the three measuring lines.

[0007] Furthermore, a first mass flow meter and a first check valve are sequentially provided between the air inlet end of the air inlet pipe and the first mixer; a second mass flow meter and a second check valve are sequentially provided between the air inlet end of the first combustible gas inlet pipe and the first mixer; a third check valve is provided between the first mixer and the second mixer; a third mass flow meter and a fourth check valve are sequentially provided between the air inlet end of the second combustible gas inlet pipe and the second mixer; and a fifth check valve is provided at the rear end of the second mixer.

[0008] Furthermore, one end of the first measuring pipeline is located between the air inlet end of the air inlet pipeline and the first mass flow meter, and a first electrically controlled valve is provided on the first measuring pipeline; one end of the second measuring pipeline is located between the first mixer and the third check valve, and a second electrically controlled valve is provided on the second measuring pipeline; one end of the third measuring pipeline is located between the second mixer and the fifth check valve, and a third electrically controlled valve is provided on the third measuring pipeline.

[0009] Furthermore, the air intake pipeline also includes a third combustible gas intake pipeline, one end of which is a third combustible gas inlet, and the other end is provided with a third mixer. The third mixer is located at the rear end of the second mixer and is used to mix air, a first combustible gas, a second combustible gas, and the third combustible gas.

[0010] Furthermore, the measuring pipeline also includes a fourth measuring pipeline, one end of which is located at the rear end of the third mixer, and the other end of which is connected to the oxygen concentration sensor.

[0011] Furthermore, a fourth mass flow meter and a sixth check valve are sequentially provided between the third combustible gas inlet and the third mixer, a seventh check valve is provided at the rear end of the third mixer, one end of the fourth measuring pipeline is located between the third mixer and the seventh check valve, and a fourth electrically controlled valve is provided on the fourth measuring pipeline.

[0012] The present invention also provides a method for measuring the concentration of multi-component combustible gas using time-division multiplexing, comprising the following steps:

[0013] S1. Control the first mass flow meter, the second mass flow meter and the third mass flow meter to introduce air, the first combustible gas and the second combustible gas into the device respectively. The air and the first combustible gas are fully mixed after passing through the first mixer, and the air, the first combustible gas and the second combustible gas are fully mixed after passing through the second mixer.

[0014] S2. Open the first solenoid valve alone to detect the oxygen concentration in the first measuring line and record it as X0. Open the second solenoid valve alone to detect the oxygen concentration in the second measuring line and record it as X1. Open the third solenoid valve alone to detect the oxygen concentration in the third measuring line and record it as X2.

[0015] S3. Let Y be the total concentration of the first and second combustible gases at the outlet of the second mixer, in %. The following relationship is derived:

[0016]

[0017] Let the concentration of the second combustible gas at the outlet of the second mixer be Y1, in %, and derive the following relationship:

[0018]

[0019] Let the concentration of the first combustible gas at the outlet of the second mixer be Y2, in %, and the following relationship be derived:

[0020]

[0021] Therefore, at the outlet of the second mixer, the concentrations of oxygen, the second combustible gas, and the first combustible gas in the ternary mixed gas are X2, X2, and X3, respectively. and The unit is %;

[0022] S4. By substituting the measured values ​​X0, X1 and X2 from step S2 into equations 1, 2 and 3 of step S3, the concentrations of oxygen, the second combustible gas and the first combustible gas are obtained.

[0023] The beneficial effects of the present invention are that the time-division multiplexing multi-component combustible gas concentration measuring device and method of the present invention can measure the concentrations of oxygen, first combustible gas and second combustible gas in a ternary gas mixture (air-first combustible gas-second combustible gas) using only one oxygen concentration sensor, which can effectively reduce the manufacturing cost and daily maintenance cost of the test equipment.

[0024] Furthermore, by using an oxygen concentration sensor to measure the oxygen concentration at different pipeline locations through time-division multiplexing, the concentration of each component gas in binary, ternary, and quaternary gas mixtures can be measured, greatly reducing the manufacturing and maintenance costs of related equipment. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Figure 1 This is a schematic diagram of the first embodiment of the time-division multiplexing multi-component combustible gas concentration measuring device of the present invention;

[0027] Figure 2 This is a schematic diagram of the second embodiment of the time-division multiplexing multi-component combustible gas concentration measuring device of the present invention.

[0028] Figure label:

[0029] 10. Air intake pipe; 11. First combustible gas intake pipe; 12. Second combustible gas intake pipe; 13. Third combustible gas intake pipe; 21. First mixer; 22. Second mixer; 23. Third mixer; 31. First measuring pipe; 32. Second measuring pipe; 33. Third measuring pipe; 34. Fourth measuring pipe; 40. Oxygen concentration sensor; 51. First mass flow meter; 52. Second mass flow meter; 53. Third mass flow meter; 54. Fourth mass flow meter; 61. First check valve; 62. Second check valve; 63. Third check valve; 64. Fourth check valve; 65. Fifth check valve; 66. Sixth check valve; 67. Seventh check valve; 71. First electrically controlled valve; 72. Second electrically controlled valve; 73. Third electrically controlled valve; 74. Fourth electrically controlled valve. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] like Figure 1 The image shows the first embodiment of the present invention, a time-division multiplexing multi-component combustible gas concentration measuring device, comprising: three inlet pipes, three measuring pipes, and an oxygen concentration sensor 40, wherein the three inlet pipes and the three measuring pipes are correspondingly arranged.

[0034] The three intake pipes are one air intake pipe 10 and two combustible gas intake pipes. The two combustible gas intake pipes include a first combustible gas intake pipe 11 and a second combustible gas intake pipe 12. A first mixer 21 is provided between the air intake pipe 10 and the first combustible gas pipe to mix air and the first combustible gas. A second mixer 22 is provided between the first mixer 21 and the second combustible gas intake pipe 12 to mix air, the first combustible gas and the second combustible gas.

[0035] The three measurement lines include a first measurement line 31, a second measurement line 32, and a third measurement line 33. One end of the first measurement line 31 is located on the air intake line 10 and at the front end of the first mixer 21. One end of the second measurement line 32 is located between the first mixer 21 and the second mixer 22. One end of the third measurement line 33 is located at the rear end of the second mixer 22.

[0036] The other ends of the first measuring line 31, the second measuring line 32, and the third measuring line 33 are all connected to oxygen concentration sensors 40. By opening the first measuring line 31, the second measuring line 32, and the third measuring line 33 at different time periods, the oxygen concentration sensors 40 are time-division multiplexed to obtain the oxygen concentration in the three measuring lines. The concentrations of the first and second combustible gases are then calculated based on the oxygen concentrations in the three measuring lines.

[0037] A first mass flow meter 51 and a first check valve 61 are sequentially provided between the air inlet end of the air inlet pipe 10 and the first mixer 21. A second mass flow meter 52 and a second check valve 62 are sequentially provided between the air inlet end of the first combustible gas inlet pipe 11 and the first mixer 21. A third check valve 63 is provided between the first mixer 21 and the second mixer 22. A third mass flow meter 53 and a fourth check valve 64 are sequentially provided between the air inlet end of the second combustible gas inlet pipe 12 and the second mixer 22. A fifth check valve 65 is provided at the rear end of the second mixer 22.

[0038] One end of the first measuring pipeline 31 is located between the air inlet end of the air inlet pipeline 10 and the first mass flow meter 51. The first measuring pipeline 31 is equipped with a first solenoid valve 71. One end of the second measuring pipeline 32 is located between the first mixer 21 and the third check valve 63. The second measuring pipeline 32 is equipped with a second solenoid valve 72. One end of the third measuring pipeline 33 is located between the second mixer 22 and the fifth check valve 65. The third measuring pipeline 33 is equipped with a third solenoid valve 73.

[0039] The time-division multiplexing method for measuring the concentration of multi-component combustible gases includes the following steps:

[0040] S1. Control the first mass flow meter 51, the second mass flow meter 52 and the third mass flow meter 53 to introduce air, the first combustible gas and the second combustible gas into the device respectively. The air and the first combustible gas are fully mixed after passing through the first mixer 21, and the air, the first combustible gas and the second combustible gas are fully mixed after passing through the second mixer 22.

[0041] S2. Open the first solenoid valve 71 alone, detect the oxygen concentration in the first measuring line 31, and record it as X0. Open the second solenoid valve 72 alone, detect the oxygen concentration in the second measuring line 32, and record it as X1. Open the third solenoid valve 73 alone, detect the oxygen concentration in the third measuring line 33, and record it as X2.

[0042] S3. Let Y be the total concentration of the first and second combustible gases at the outlet of the second mixer 22, in %. The following relationship is derived:

[0043]

[0044] Let the concentration of the second combustible gas at the outlet of the second mixer 22 be Y1, in %, and the following relationship be derived:

[0045]

[0046] Let the concentration of the first combustible gas at the outlet of the second mixer 22 be Y2, in %, and the following relationship be derived:

[0047]

[0048] Therefore, at the outlet of the second mixer 22, the concentrations of oxygen, the second combustible gas, and the first combustible gas in the ternary mixed gas are respectively X2, and The unit is %;

[0049] S4. By substituting the measured values ​​X0, X1 and X2 from step S2 into equations 1, 2 and 3 of step S3, the concentrations of oxygen, the second combustible gas and the first combustible gas are obtained.

[0050] In this embodiment, firstly, the first mass flow meter 51, the second mass flow meter 52, and the third mass flow meter 53 are controlled. The first combustible gas is high-purity methane, and the second combustible gas is high-purity hydrogen. Clean air, high-purity methane, and high-purity hydrogen are introduced into the system and maintained for 2-10 minutes to stabilize the airflow in the gas distribution system and ensure there is no residual gas. Next, the first electrically controlled valve 71 is opened (the second electrically controlled valve 72 and the third electrically controlled valve 73 are closed) and maintained for 2-10 minutes. The oxygen concentration in the clean air is measured using the oxygen concentration sensor 40 and recorded as X0. Then, the second electrically controlled valve 72 is opened (the first electrically controlled valve 71 and the third electrically controlled valve 73 are closed) and maintained for 2-10 minutes. The oxygen concentration in the second measuring line 32 is measured using the oxygen concentration sensor 40 and recorded as X1. Finally, the third electrically controlled valve 73 is opened (the first electrically controlled valve 71 and the second electrically controlled valve 72 are closed) and maintained for 2-10 minutes. The oxygen concentration in the third measuring line 33 is measured using the oxygen concentration sensor 40 and recorded as X2.

[0051] Assuming that in the above gas mixing measurement process, X0 = 21.0%, X1 = 19.5%, and X2 = 18.5%, then the concentrations of oxygen, hydrogen, and methane in the ternary mixed gas (air-methane-hydrogen) at the outlet of the second mixer 22 are:

[0052] Oxygen concentration x2 = 18.5%

[0053] hydrogen concentration

[0054] methane concentration

[0055] like Figure 2 The image shows the second embodiment of the present invention. The difference between the second and first embodiments is that the air intake pipe further includes a third combustible gas intake pipe 13. One end of the third combustible gas intake pipe 13 is a third combustible gas inlet, and the other end is provided with a third mixer 23. The third mixer 23 is located at the rear end of the second mixer 22. The third mixer 23 is used to mix air, the first combustible gas, the second combustible gas, and the third combustible gas.

[0056] The measuring line also includes a fourth measuring line 34, one end of which is located at the rear end of the third mixer 23, and the other end of which is connected to the oxygen concentration sensor 40.

[0057] A fourth mass flow meter 54 and a sixth check valve 66 are sequentially provided between the third combustible gas inlet and the third mixer 23. A seventh check valve 67 is provided at the rear end of the third mixer 23. One end of the fourth measuring pipeline 34 is located between the third mixer 23 and the seventh check valve 67. A fourth electrically controlled valve 74 is provided on the fourth measuring pipeline 34.

[0058] In this embodiment, by opening the first solenoid valve 71, the second solenoid valve 72, the third solenoid valve 73 and the fourth solenoid valve 74 at different time periods, the oxygen concentration in the first measuring pipeline 31, the second measuring pipeline 32, the third measuring pipeline 33 and the fourth measuring pipeline 34 are measured by the oxygen concentration sensor 40 and recorded as X0, X1, X2 and X3 respectively.

[0059] (1) The oxygen concentration in the binary mixed gas in the first measuring pipeline 31 is X1;

[0060] Let the concentration of the first combustible gas at the outlet of the first mixer 21 be Y, in %, and the following relationship be derived:

[0061]

[0062] Therefore, at the outlet of the first mixer 21, the concentrations of oxygen and the first combustible gas in the binary mixed gas (air-first combustible gas) are X1 and X2, respectively. The unit is %.

[0063] (2) The oxygen concentration in the ternary mixed gas in the second measuring pipeline 35 is X2;

[0064] ①Assuming the total concentration of the first and second combustible gases at the outlet of the second mixer 22 is Y, in %, then the following relationship exists.

[0065]

[0066] ②Assuming the concentration of the second combustible gas at the outlet of the second mixer 22 is Y2, in %, then the following relationship exists.

[0067]

[0068] ③Assuming the concentration of the first combustible gas at the outlet of the second mixer 22 is Y1 (in %), then the following relationship exists.

[0069]

[0070] Therefore, at the outlet of mixer 2, the concentrations of oxygen, the first combustible gas, and the second combustible gas in the ternary gas mixture (air – first combustible gas – second combustible gas) are X2, X2, and X3, respectively. and The unit is %.

[0071] (3) Assume that the oxygen concentration in the quaternary mixed gas at the outlet of the third mixer 23 is X3;

[0072] ①Assuming the total concentration of the first, second, and third combustible gases at the outlet of the third mixer 23 is Y, in %, then the following relationship exists.

[0073]

[0074] ②Assuming the concentration of the third combustible gas at the outlet of the third mixer 23 is Y3, in %, then the following relationship exists.

[0075]

[0076] ③Assuming the concentrations of the second and third combustible gases at the outlet of the third mixer 23 are Y2 + Y3, in %, then the following relationship exists.

[0077]

[0078] Right now

[0079] ④ Assuming the concentration of the first combustible gas at the outlet of the third mixer 23 is Y1, in %, then the following relationship exists.

[0080]

[0081] Therefore, at the outlet of the third mixer 23, the concentrations of oxygen, the first combustible gas, the second combustible gas, and the third combustible gas in the quaternary mixed gas (air – first combustible gas – second combustible gas – third combustible gas) are X3, respectively. and The unit is %.

[0082] In this embodiment, the first mass flow meter 51, the second mass flow meter 52, the third mass flow meter 53, and the fourth mass flow meter 54 are controlled first. It is assumed that the first combustible gas is high-purity methane, the second combustible gas is high-purity hydrogen, and the third combustible gas is high-purity ethylene. Clean air, high-purity methane, high-purity hydrogen, and high-purity ethylene are introduced into the system and maintained for 2-10 minutes to stabilize the airflow in the gas distribution system and ensure that there is no residual gas. Next, open the first solenoid valve 71 (close the second solenoid valve 72, the third solenoid valve 73, and the fourth solenoid valve 74) and maintain for 2-10 minutes. Use the oxygen concentration sensor 40 to measure the oxygen concentration in the clean air and record it as X0. Then, open the second solenoid valve 72 (close the first solenoid valve 71, the third solenoid valve 73, and the fourth solenoid valve 74) and maintain for 2-10 minutes. Use the oxygen concentration sensor 40 to measure the oxygen concentration in the second measuring line 32 and record it as X1. Next, open the third solenoid valve 73 (close the first solenoid valve 71, the second solenoid valve 72, and the fourth solenoid valve 74) and maintain for 2-10 minutes. Use the oxygen concentration sensor 40 to measure the oxygen concentration in the third measuring line 33 and record it as X2. Finally, open the fourth solenoid valve 74 (close the first solenoid valve 71, the second solenoid valve 72, and the third solenoid valve 73) and maintain for 2-10 minutes. Use the oxygen concentration sensor 40 to measure the oxygen concentration in the fourth measuring line 34 and record it as X3.

[0083] Assuming that in the above gas mixing measurement process, X0 = 21.0%, X1 = 19.5%, X2 = 18.5%, and X3 = 17.5%, then the concentrations of oxygen, methane, hydrogen, and ethylene in the ternary mixed gas (air-methane-hydrogen-ethylene) at the outlet of the third mixer 23 are:

[0084] Oxygen concentration x3 = 17.5%

[0085] methane concentration

[0086] Hydrogen alkyl concentration

[0087] ethylene concentration

[0088] The time-division multiplexing multi-component combustible gas concentration measuring device and method of the present invention can measure the concentrations of oxygen, first combustible gas and second combustible gas in a ternary gas mixture (air-first combustible gas-second combustible gas) using only one oxygen concentration sensor 40, which can effectively reduce the manufacturing cost and daily maintenance cost of the test equipment.

[0089] Furthermore, by using an oxygen concentration sensor 40, the oxygen concentration at different pipeline locations can be measured through time-division multiplexing, thereby enabling the measurement of the concentration of each component gas in binary, ternary, and quaternary mixed gases, significantly reducing the manufacturing and maintenance costs of related equipment.

[0090] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A time-division multiplexing multi-component combustible gas concentration measuring device, characterized in that, include: At least three air intake pipes are provided, namely one air intake pipe (10) and at least two combustible gas intake pipes. The two combustible gas intake pipes include a first combustible gas intake pipe (11) and a second combustible gas intake pipe (12). A first mixer (21) is provided between the air intake pipe (10) and the first combustible gas intake pipe (11) to mix air and a first combustible gas. A second mixer (22) is provided between the first mixer (21) and the second combustible gas intake pipe (12) to mix air, the first combustible gas and the second combustible gas. At least three measuring lines are provided, including at least three air intake lines and at least three corresponding measuring lines, including a first measuring line (31), a second measuring line (32) and a third measuring line (33). One end of the first measuring line (31) is provided on the air intake line (10) and located at the front end of the first mixer (21). One end of the second measuring line (32) is provided between the first mixer (21) and the second mixer (22). One end of the third measuring line (33) is provided at the rear end of the second mixer (22). The oxygen concentration sensor (40) is connected to the other end of the first measuring pipeline (31), the other end of the second measuring pipeline (32), and the other end of the third measuring pipeline (33). By opening the first measuring pipeline (31), the second measuring pipeline (32), and the third measuring pipeline (33) at different time periods, the oxygen concentration sensor (40) is time-division multiplexed to obtain the oxygen concentration in the three measuring pipelines. The concentrations of the first combustible gas and the second combustible gas are calculated based on the oxygen concentration in the three measuring pipelines.

2. The time-division multiplexing multi-component combustible gas concentration measuring device as described in claim 1, characterized in that, A first mass flow meter (51) and a first check valve (61) are sequentially provided between the air inlet end of the air inlet pipe (10) and the first mixer (21). A second mass flow meter (52) and a second check valve (62) are sequentially provided between the air inlet end of the first combustible gas inlet pipe (11) and the first mixer (21). A third check valve (63) is provided between the first mixer (21) and the second mixer (22). A third mass flow meter (53) and a fourth check valve (64) are sequentially provided between the air inlet end of the second combustible gas inlet pipe (12) and the second mixer (22). A fifth check valve (65) is provided at the rear end of the second mixer (22).

3. The time-division multiplexing multi-component combustible gas concentration measuring device as described in claim 2, characterized in that, One end of the first measuring pipeline (31) is located between the air inlet end of the air inlet pipeline (10) and the first mass flow meter (51). The first measuring pipeline (31) is provided with a first solenoid valve (71). One end of the second measuring pipeline (32) is located between the first mixer (21) and the third check valve (63). The second measuring pipeline (32) is provided with a second solenoid valve (72). One end of the third measuring pipeline (33) is located between the second mixer (22) and the fifth check valve (65). The third measuring pipeline (33) is provided with a third solenoid valve (73).

4. The time-division multiplexing multi-component combustible gas concentration measuring device as described in claim 1, characterized in that, The combustible gas inlet pipeline also includes a third combustible gas inlet pipeline (13). One end of the third combustible gas inlet pipeline (13) is a third combustible gas inlet, and the other end is provided with a third mixer (23). The third mixer (23) is located at the rear end of the second mixer (22). The third mixer (23) is used to mix air, the first combustible gas, the second combustible gas and the third combustible gas.

5. The time-division multiplexing multi-component combustible gas concentration measuring device as described in claim 4, characterized in that, The measuring pipeline also includes a fourth measuring pipeline (34), one end of which is located at the rear end of the third mixer (23), and the other end of which is connected to the oxygen concentration sensor (40).

6. The time-division multiplexing multi-component combustible gas concentration measuring device as described in claim 5, characterized in that, A fourth mass flow meter (54) and a sixth check valve (66) are sequentially provided between the third combustible gas inlet and the third mixer (23). A seventh check valve (67) is provided at the rear end of the third mixer (23). One end of the fourth measuring pipeline (34) is located between the third mixer (23) and the seventh check valve (67). A fourth electrically controlled valve (74) is provided on the fourth measuring pipeline (34).

7. A method for measuring the concentration of multi-component combustible gas using time-division multiplexing, characterized in that, Includes the following steps: S1. Control the first mass flow meter (51), the second mass flow meter (52) and the third mass flow meter (53) to respectively introduce air, the first combustible gas and the second combustible gas into the time-division multiplexing multi-component combustible gas concentration measuring device as described in claim 3. The air and the first combustible gas are fully mixed after passing through the first mixer (21), and the air, the first combustible gas and the second combustible gas are fully mixed after passing through the second mixer (22). S2. Open the first solenoid valve (71) alone, detect the oxygen concentration of the first measuring line (31) and record it as X0. Open the second solenoid valve (72) alone, detect the oxygen concentration of the second measuring line (32) and record it as X1. Open the third solenoid valve (73) alone, detect the oxygen concentration of the third measuring line (33) and record it as X2. S3. Let Y be the total concentration of the first and second combustible gases at the outlet of the second mixer (22), in %, and derive the following relationship: = ,Right now = (Equation 1) Let the concentration of the second combustible gas at the outlet of the second mixer (22) be Y1, in %, and derive the following relationship: = ,Right now = (Equation 2) Let the concentration of the first combustible gas at the outlet of the second mixer (22) be Y2, in %, and derive the following relationship: (Equation 3) Therefore, at the outlet of the second mixer (22), the concentrations of oxygen, the second combustible gas, and the first combustible gas in the ternary mixed gas are respectively , and The unit is % S4. By substituting the measured values ​​X0, X1 and X2 from step S2 into equations 1, 2 and 3 of step S3, the concentrations of oxygen, the second combustible gas and the first combustible gas are obtained.

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