Mechanical valve detection device for gas chromatography

Abstract

The application specifically relates to a mechanical valve detection device for gas chromatography, which is electrically connected with a control circuit board and comprises a pressure stabilizing valve, electromagnetic valves, a to-be-detected steady flow valve, a flow sensor, a pressure sensor, a to-be-detected back pressure valve, a chromatographic column and a column oven which are connected through pipelines, wherein the pressure stabilizing valve is connected with an output end of carrier gas. The electromagnetic valves comprise a first electromagnetic valve, a second electromagnetic valve and a third electromagnetic valve, the pressure stabilizing valve is connected with the first electromagnetic valve, the first electromagnetic valve is provided with a first opening and a second opening, and the second electromagnetic valve is provided with a third opening and a fourth opening. The to-be-detected steady flow valve is connected between the first opening and the third opening, the second opening and the fourth opening are connected through pipelines, a first switch is arranged in the first electromagnetic valve, and a second switch is arranged in the second electromagnetic valve. The second electromagnetic valve is connected with the flow sensor, the flow sensor is connected with a split sample injection block, the split sample injection block is connected with the chromatographic column and a three-way joint, and the three-way joint is connected with the pressure sensor and the to-be-detected back pressure valve.

Description

Technical Field

[0001] This invention relates to the technical field of gas chromatographs, and in particular to a mechanical valve detection device for gas chromatography. Background Technology

[0002] A gas chromatograph is a chromatographic analysis instrument that uses gas as the mobile phase. Its principle mainly utilizes the differences in boiling point, polarity, and adsorption properties of substances to separate mixtures. The sample to be analyzed is vaporized in the vaporization chamber and then carried into the chromatographic column by an inert gas (i.e., carrier gas, also known as the mobile phase). The column contains a liquid or solid stationary phase. Due to differences in the distribution or adsorption coefficients of the components in the sample between the mobile phase (gas phase) and the stationary phase (liquid or solid phase) in the column, under the flushing of the carrier gas, the components undergo repeated distribution between the two phases, resulting in separation within the column. Then, a detector connected to the column detects each component based on its physicochemical properties, thus achieving qualitative and quantitative analysis of the sample gas.

[0003] Mechanical valves are generally used to control gas chromatographs (GCs). Due to their high cost-effectiveness and instrument stability, they are particularly suitable for applications requiring simple detection methods and where frequent changes in flow rate and pressure are not necessary, thus maintaining a place in the market. Among the mechanical valves used in GCs, the flow control valve and back pressure valve in the controller circuit play a crucial role. To ensure the repeatability of sample peak areas and the stability of retention times within the GC, the total flow rate and in-column pressure must remain stable. In constant pressure mode, fluctuations in total flow rate and pressure should not be too large, otherwise, the retention time of the eluted peaks will be affected.

[0004] Therefore, due to differences in processing and installation techniques, some mechanical valves have problems such as low accuracy in stabilizing flow and pressure, large fluctuations, large drift, and long durations. As a result, the reproducibility of peak area and retention time in gas chromatographs using such mechanical valves is not good. Summary of the Invention

[0005] Therefore, it is necessary to provide a mechanical valve detection device for gas chromatography that can improve the repeatability of peak area and retention time in gas chromatographs, addressing the aforementioned technical problems.

[0006] A mechanical valve detection device for gas chromatography, electrically connected to a control circuit board, includes a pressure regulating valve, multiple solenoid valves, a flow regulating valve to be tested, a flow sensor, a pressure sensor, a back pressure valve to be tested, a chromatographic column, and a column oven, all connected by pipelines. The input end of the pressure regulating valve is connected to the output end of the carrier gas. The multiple solenoid valves include a first solenoid valve, a second solenoid valve, and a third solenoid valve. The output end of the pressure regulating valve is connected to the input end of the first solenoid valve. The output end of the first solenoid valve has a first opening and a second opening, and the input end of the second solenoid valve has a third opening and a fourth opening. The flow regulating valve to be tested is connected between the first opening and the third opening through the pipeline, and the second opening and the fourth opening are connected through the pipeline. A first switch is provided inside the first solenoid valve, and a second switch is provided inside the second solenoid valve.

[0007] The output of the second solenoid valve is connected to the input of the flow sensor. The output of the flow sensor is connected to a split injection block. The output of the split injection block is connected to the chromatographic column. The pressure sensor and the third solenoid valve are connected to the split injection block via a three-way connector. The output of the third solenoid valve is connected to the input of the back pressure valve to be tested.

[0008] Furthermore, the flow sensor is a high-precision flow sensor.

[0009] Furthermore, the pressure sensor is a high-precision pressure sensor.

[0010] Furthermore, the three-way connector includes a first connector, a second connector, and a third connector. The first connector is connected to the output end of the shunt injection block through the pipeline; the second connector is connected to the pressure sensor; and the third connector is connected to the input end of the third solenoid valve through the pipeline.

[0011] Furthermore, the output end of the split injection block includes a first output end and a second output end. The first output end is connected to the chromatographic column through the tubing; the second output end is connected to the first connector through the tubing.

[0012] Furthermore, the column temperature chamber is equipped with a temperature control device, which is electrically connected to the control circuit board.

[0013] Furthermore, the control circuit board is electrically connected to a remote control terminal.

[0014] The aforementioned mechanical valve detection device for gas chromatography operates as follows: When the gas source is turned on, the pressure regulating valve to be tested is adjusted so that the carrier gas stabilizes at a certain pressure after passing through it. At this time, the first switch of the first solenoid valve is opened to the second opening, the second switch of the second solenoid valve is opened to the fourth opening, and the input and output ends of the third solenoid valve are closed. The carrier gas is then vented through the chromatographic column, allowing heating to begin by setting the column temperature without damaging the column, thus improving efficiency. In another configuration, the input end of the flow regulating valve to be tested is connected to the first opening of the first solenoid valve, and the output end of the flow regulating valve to be tested is connected to the third opening of the second solenoid valve. The input end of the back pressure valve to be tested is connected to the output end of the third solenoid valve, and the outlet of the back pressure valve to be tested is vented. The first switch of the first solenoid valve is then opened to the first opening, and the second switch of the second solenoid valve is opened to the third opening, opening the third solenoid valve. The flow regulating valve to be tested is adjusted to the set flow rate, and the back pressure valve to be tested is adjusted to the set pressure. Testing then begins. The control circuit board collects and transmits the monitored flow and pressure data in real time to a remote control terminal, which then plots the corresponding curves based on the received data. After the test is completed, the flow rate and pressure curves provide a clear visual indication of the valve's operating status and whether its performance meets our requirements. Therefore, the control circuit board design enables a high degree of automation in the device. By analyzing the operating status and performance of the valve, a more stable carrier gas is selected, resulting in better repeatability of the peak area and retention time of the carrier gas measured by the gas chromatograph, thus improving detection accuracy. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the mechanical valve detection device for gas chromatography in the initial stage of startup according to an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of the detection process structure of the mechanical valve detection device for gas chromatography in this embodiment.

[0017] In the diagram: 100, pressure regulating valve; 200, first solenoid valve; 210, first switch; 220, first opening; 230, second opening; 300, second solenoid valve; 310, third opening; 320, fourth opening; 330, second switch; 400, flow regulating valve to be tested; 500, flow sensor; 600, column oven; 610, split injection block; 611, first output terminal; 612, second output terminal; 620, chromatographic column; 700, tee connector; 710, first connector; 720, second connector; 721, pressure sensor; 730, third connector; 800, third solenoid valve; 900, back pressure valve to be tested. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figures 1 to 2 As shown, in one embodiment, a mechanical valve detection device for gas chromatography is electrically connected to a control circuit board, which is electrically connected to a remote control terminal. The device includes a pressure regulating valve 100, a solenoid valve, a flow regulating valve 400 to be tested, a flow sensor 500, a pressure sensor 721, a back pressure valve 900 to be tested, a chromatographic column 620, and a column oven 600, all connected sequentially via pipelines. The input end of the pressure regulating valve 100 is connected to the output end of the carrier gas. The solenoid valve includes a first solenoid valve 200, a second solenoid valve 300, and a third solenoid valve 800. The output end of the pressure regulating valve 100 is connected to the first solenoid valve 200 via a pipeline. The output end of the first solenoid valve 200 has a first opening 220 and a second opening 230. A first switch 210 is provided inside the first solenoid valve 200, which can be adjusted to connect the input end of the first solenoid valve 200 to either the first opening 220 or the second opening 230. The input end of the second solenoid valve 300 has a third opening 310 and a fourth opening 320. The flow regulator 400 under test is connected between the first opening 220 and the third opening 310 via a pipeline, and the second opening 230 and the fourth opening 320 are connected via a pipeline. The input end of the flow regulator 400 under test is connected to the first opening 220, and the output end is connected to the third opening 310. The second solenoid valve 300 has a second switch 330 inside. By adjusting the third switch 330, the output end of the second solenoid valve 300 can be connected to either the third opening 310 or the fourth opening 320, thereby determining whether the carrier gas enters the second solenoid valve 300 from the first solenoid valve 200 through the flow regulator 400 under test.

[0020] In this embodiment, the output end of the second solenoid valve 300 is connected to the input end of the flow sensor 500 via a pipeline. The flow sensor 500 is a high-precision flow sensor. The output end of the flow sensor 500 is connected to a split injection block 610 via a pipeline. The first output end 611 and the second output end 612 of the split injection block 610 achieve the purpose of splitting the carrier gas. The first output end 611 is connected to the chromatographic column 620, and the second output end 612 is connected to a tee connector 700. Both the split injection block 610 and the chromatographic column 620 are located inside the column oven 600, which is equipped with a temperature control device electrically connected to a control circuit board to control the temperature inside the column oven 600. The three-way connector 700 includes a first connector 710, a second connector 720, and a third connector 730. The first connector 710 is connected to the output end of one of the pipelines of the shunt injection block 610 via a pipeline. The second connector 720 is connected to the pressure sensor 721, which is a high-precision pressure sensor. The third connector 730 is connected to the input end of the third solenoid valve 800, and the output end of the third solenoid valve 800 is connected to the input end of the back pressure valve 900 to be tested.

[0021] In this embodiment, the remote control terminal is equipped with a software system for collecting and processing detection data.

[0022] The aforementioned mechanical valve detection device for gas chromatography operates as follows: When the gas source is turned on, the pressure regulating valve to be tested is adjusted so that the carrier gas stabilizes at a certain pressure after passing through it. At this time, the first switch of the first solenoid valve is opened to the second opening, the second switch of the second solenoid valve is opened to the fourth opening, and the input and output ends of the third solenoid valve are closed. The carrier gas is then vented through the chromatographic column, allowing heating to begin by setting the column temperature without damaging the column, thus improving efficiency. In another configuration, the input end of the flow regulating valve to be tested is connected to the first opening of the first solenoid valve, and the output end of the flow regulating valve to be tested is connected to the third opening of the second solenoid valve. The input end of the back pressure valve to be tested is connected to the output end of the third solenoid valve, and the outlet of the back pressure valve to be tested is vented. The first switch of the first solenoid valve is then opened to the first opening, and the second switch of the second solenoid valve is opened to the third opening, opening the third solenoid valve. The flow regulating valve to be tested is adjusted to the set flow rate, and the back pressure valve to be tested is adjusted to the set pressure. Testing then begins. The control circuit board collects and transmits the monitored flow and pressure data in real time to a remote control terminal, which then plots the corresponding curves based on the received data. After the test is completed, the flow rate and pressure curves provide a clear visual indication of the valve's operating status and whether its performance meets our requirements. Therefore, the control circuit board design enables a high degree of automation in the device. By analyzing the operating status and performance of the valve, a more stable carrier gas is selected, resulting in better repeatability of the peak area and retention time of the carrier gas measured by the gas chromatograph, thus improving detection accuracy.

[0023] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A mechanical valve detection device for gas chromatography, characterized in that, The system is electrically connected to a control circuit board, including a pressure regulating valve, multiple solenoid valves, a flow regulating valve to be tested, a flow sensor, a pressure sensor, a back pressure valve to be tested, a chromatographic column, and a column oven, all connected via pipelines. The input end of the pressure regulating valve is connected to the output end of the carrier gas. The multiple solenoid valves include a first solenoid valve, a second solenoid valve, and a third solenoid valve. The output end of the pressure regulating valve is connected to the input end of the first solenoid valve. The output end of the first solenoid valve has a first opening and a second opening, and the input end of the second solenoid valve has a third opening and a fourth opening. The flow regulating valve to be tested is connected between the first opening and the third opening via the pipeline, and the second opening and the fourth opening are connected via the pipeline. A first switch is installed inside the first solenoid valve, and a second switch is installed inside the second solenoid valve. The output of the second solenoid valve is connected to the input of the flow sensor. The output of the flow sensor is connected to a split injection block. The output of the split injection block is connected to the chromatographic column. The pressure sensor and the third solenoid valve are connected to the split injection block via a three-way connector. The output of the third solenoid valve is connected to the input of the back pressure valve to be tested. The flow sensor is a high-precision flow sensor. The pressure sensor is a high-precision pressure sensor. The control circuit board is electrically connected to the first switch of the first solenoid valve, the second switch of the second solenoid valve, the third solenoid valve, the flow sensor, and the pressure sensor, respectively, and is used to control the switching state of the solenoid valves and collect flow and pressure data in real time. The control circuit board is also electrically connected to a remote control terminal, which can plot flow and pressure curves based on the collected data to intuitively judge the performance of the valve under test. The three-way connector includes a first connector, a second connector, and a third connector. The first connector is connected to the output end of the shunt injection block through the pipeline; the second connector is connected to the pressure sensor; and the third connector is connected to the input end of the third solenoid valve through the pipeline.

2. The mechanical valve detection device for gas chromatography according to claim 1, characterized in that, The output end of the split injection block includes a first output end and a second output end. The first output end is connected to the chromatographic column through the tubing; the second output end is connected to the first connector through the tubing.

3. The mechanical valve detection device for gas chromatography according to claim 1, characterized in that, The column temperature chamber is equipped with a temperature control device, which is electrically connected to the control circuit board.

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