Gas sample concentration device and gas analyzer

Abstract

The goal is to facilitate the control of gas concentration. [Solution] A gas sample concentration apparatus 100 includes a container 110, piping 120, and a control mechanism 130, wherein the container 110 includes a temperature gradient region 110a which is a region having a temperature gradient inside, the piping 120 is a gas flow path and at least a portion of it can be located in the temperature gradient region 110a, and the control mechanism 130 controls the position of the piping 120 in the temperature gradient region 110a according to the target temperature of the gas.

Description

Technical Field

[0001] The present invention relates to a gas sample concentration device and a gas analyzer.

Background Art

[0002] One method for measuring the gas concentration in the atmosphere is a gas chromatograph. In a gas chromatograph, it is preferable to increase the concentration of the gas to be analyzed in order to improve the measurement accuracy. As a technique related to a method for increasing the purity of a gas, Patent Document 1 discloses a technique for burning methane in an organic combustion catalyst tube in an ultra-high purity nitrogen purification method using compressed air.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] One method for concentrating a specific component contained in a gas is to pass the gas through a cooled pipe to liquefy the specific component and then vaporize the component. In this method, it is important to accurately control the temperature.

Means for Solving the Problems

[0005] According to the present invention, the following gas sample concentration device and gas analyzer are provided. [1] A container including an internal temperature gradient region that is a region having a temperature gradient, A pipe that serves as a gas flow path and at least a part of which can be located in the temperature gradient region, A control mechanism that controls the position of the pipe in the temperature gradient region according to the target temperature of the gas, A gas sample concentration device including the above. [2] A cold source can be placed in the aforementioned container. In the aforementioned temperature gradient region, the temperature increases as you move away from the cold source. [1] The gas sample concentration apparatus described above. [3] The cooling source includes a heat exchanger, liquid nitrogen, liquid helium, and at least one of solid carbon dioxide. [2] The gas sample concentration apparatus described above. [4] Includes a temperature detection unit that detects the temperature of the aforementioned pipe, The control mechanism controls the position of the pipe using the difference between the temperature of the pipe detected by the temperature detection unit and the target temperature. A gas sample concentration apparatus according to any one of [1] to [3]. [5] Includes a heat source located on the opposite side of the cold source via the temperature gradient region, A gas sample concentration apparatus as described in [2] or [3]. [6] A gas analyzer having a gas sample concentration device as described in any of [1] to [5]. [Effects of the Invention]

[0006] According to the present invention, the temperature of the gas can be controlled with high precision. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram shows an overview of the gas analyzer according to the first embodiment. [Figure 2] Figure 1 shows an overview of the gas sample concentration apparatus according to the first embodiment. [Figure 3] Figure 2 shows an overview of the gas sample concentration apparatus according to the first embodiment. [Figure 4] Figure 3 shows an overview of the gas sample concentration apparatus according to the first embodiment. [Figure 5] This is a flowchart illustrating the operation of the gas sample concentration apparatus according to the first embodiment. [Figure 6] It is a diagram showing an example of the hardware configuration of the control mechanism according to the first embodiment. [Figure 7] It is a flowchart showing the operation of the gas sample concentrator according to the second embodiment.

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

[0009] [First Embodiment] FIG. 1 is a block diagram showing an overview of the configuration of the gas analyzer 1000 according to the first embodiment. Also, the arrows in FIG. 1 indicate the gas flow. The gas analyzer 1000 includes a carrier gas introduction unit 210, a sample introduction unit 220, a gas sample concentrator 100, a column 300, and a detector 400, and has an analysis unit located on the downstream side of the gas sample concentrator 100. As the detector 400, a thermal conductivity detector or an electron capture detector can be used. First, a carrier gas is introduced from the carrier gas introduction unit 210, and a gas to be analyzed is added to this carrier gas from the sample introduction unit 220. Thereafter, the component to be analyzed in the carrier gas is concentrated by the gas sample concentrator 100 and then transported to a column 300, a thermal conductivity detector 400, and an electron capture detector 500, which are examples of the analysis unit. In the column 300, the components contained in the analysis sample are separated to obtain a gas phase. Thereafter, the components contained in the gas to be analyzed are detected by the thermal conductivity detector 400 and the electron capture detector 500.

[0010] The gas analyzer 1000 according to the present embodiment can improve the accuracy of component detection because the analysis sample is concentrated by the gas sample concentrator 100 at a stage before each component contained in the analysis sample is detected by the detector.

[0011] Next, the gas sample concentration device 100 according to the present embodiment will be described in detail. FIG. 2 is a schematic diagram of the gas sample concentration device 100 according to the present embodiment. The gas sample concentration device 100 includes a container 110, a pipe 120, and a control mechanism 130.

[0012] [Container 110] The container 110 is a container having a capacity of, for example, 200 cm 3 or more and 20000 cm 3 or less. The shape of the container 110 is, for example, a cylinder or a quadrangular prism that is hollow and has an opening on the upper surface, but is not limited thereto. The area of the bottom surface of the container 110 is, as an example, 20 cm 2 or more and 1200 cm 2 or less. The container 110 is formed of, for example, metal or glass and has heat insulation properties.

[0013] And the container 110 includes a temperature gradient region 110a that is a region having a temperature gradient inside. As an example, in the temperature gradient region 110a, the temperature rises as it moves away from the end portion 110b on the bottom surface side.

[0014] The method for forming a temperature gradient region 110a inside the container 110 is not particularly limited, but as shown in Figure 3, the container 110 can accommodate a cold source 110d, and the temperature gradient region 110a may be formed using the cold source 110d. The cold source 110d is, for example, a device such as a heat exchanger. An example of a heat exchanger is an FPSC (Free Piston Stirling Cooler) (manufactured by Twinbird Corporation). Alternatively, the cold source 110d may contain at least one of the following materials: liquid nitrogen, liquid helium, and solid carbon dioxide (dry ice). Alternatively, it may contain solid nitrogen. For example, the temperature gradient region 110a is formed by placing the cold source 110d at the bottom end 110b of the container 110. Furthermore, the cold source 110d may be at least one of liquid nitrogen, liquid helium, and solid nitrogen directly placed in the container 110, or it may be a component such as piping provided in the container 110 through which a liquid material such as liquid nitrogen or liquid helium flows. If the container 110 has a cold source 110d, the temperature in the temperature gradient region 110a increases as you move away from the cold source 110d.

[0015] Furthermore, as shown in Figure 4, the container 110 may include a heat source 110e located on the opposite side of the cold source 110d via a temperature gradient region 110a. The heat source 110e is, for example, a resistance heater. In this case, the temperature increases in the temperature gradient region 110a from the cold source 110d side towards the heat source side.

[0016] [Piping 120] The piping 120 serves as a gas flow path containing the carrier gas and the analytical sample, and at least a portion of it is located within the temperature gradient region 110a. As a result, the gas flowing through the piping 120 passes through the temperature gradient region 110a, causing the gas temperature to decrease and thus becoming concentrated.

[0017] The piping 120 is part of the piping that connects the sample introduction section 220 and the analysis section. An example of the shape of the piping 120 will be described in detail. The piping 120 is U-shaped in the section of the piping 120 located inside the container 110, from the upstream part 120a in the gas flow to the downstream part 120c in the gas flow.

[0018] Furthermore, the pipe 120 extends from the upstream portion 120a of the pipe 120 to the lower end 120b of the pipe 120 on the bottom side (cold source 110d side) of the container 110, towards the bottom side (cold source 110d side). In addition, the pipe 120 is folded back at the lower end 120b of the pipe 120, and extends from the lower end 120b to the downstream portion 120c of the pipe 120 towards the opening side of the container 110. At least the lower end 120b of the pipe 120 can be located in the temperature gradient region 110a, and furthermore, it is in a state where it can move in the direction in which the temperature is changing within the temperature gradient region 110a.

[0019] The temperature range of the temperature gradient region 110a is, for example, the temperature of the cold source 110d at the bottom and the temperature of room temperature at the top. For example, if the cold source 110d contains liquid nitrogen, the temperature range will be from 30°C (room temperature) to -196°C.

[0020] [Control mechanism 130] The control mechanism 130 controls the position of the pipe 120 in the temperature gradient region 110a, for example, the position of the lower end 120b of the pipe 120 on the bottommost side (cold source 110d side) of the container 110, according to the target temperature of the gas. The control mechanism 130 also controls the position of the pipe 120 by moving it in the direction in which the temperature in the temperature gradient region 110a is changing. This makes it possible to control the temperature of the gas flowing through the pipe 120 according to, for example, the component to be analyzed.

[0021] An example of the specific configuration of the control mechanism 130 will be described. The control mechanism 130 includes, for example, a control unit 131, a precision cylinder 132, and a joint 133. The control unit 131 controls the operation of the precision cylinder 132. The control unit 131 controls the position of the pipe 120, which is connected to the precision cylinder 132 via the joint 133, by controlling the operation of the precision cylinder 132. The error in position control by the precision cylinder 132 is preferably, for example, 1 mm or less. In other words, by using the precision cylinder 132, the position of the lower end 120b of the pipe 120 is controlled in units of 1 mm or less.

[0022] Next, a specific example of the control performed by the control unit 131 will be described. For example, when the control unit 131 acquires temperature information indicating the target temperature of the gas, it controls the position of the piping 120 to a position in the temperature gradient region 110a corresponding to the target temperature of the gas. For example, the control unit 131 has in advance stored control information indicating which target temperature corresponds to which position (e.g., height) in the temperature gradient region 110a, and uses this control information to identify the position corresponding to the target temperature of the gas. Then, the control unit 131 positions, for example, the lower end of the piping 120 at the identified position.

[0023] The control information could be, for example, a table that associates target temperature with position (height), or a function that calculates position (height) from the target temperature.

[0024] Next, we will specifically explain the process by which the control unit 131 controls the position of the piping. Figure 5 is a flowchart illustrating the process by which the control unit 131 controls the position of the piping.

[0025] The control unit 131 first acquires temperature information indicating the target temperature of the gas (step S100). The temperature information is input by, for example, the user.

[0026] Next, the control unit 131 determines the position to control the piping 120 (step S200). For example, the control unit 131 determines the position in the temperature gradient region 110a corresponding to the target temperature of the gas, and positions the lower end 120b of the piping 120 at the determined position.

[0027] Figure 6 is a block diagram showing an example of the hardware configuration of the control unit 131. The control unit 131 may be implemented using hardware that performs each function (e.g., hardwired electronic circuits), or it may be implemented using a combination of hardware and software (e.g., a combination of electronic circuits and a program that controls them). The following will further explain the case where each function of the control unit 131 is implemented using a combination of hardware and software.

[0028] The control unit 131 includes a bus 1020, a processor 1040, a memory 1060, a storage device 1080, an input / output interface 1100, and a network interface 1120. The bus 1020 is a data transmission path for the processor 1040, memory 1060, storage device 1080, input / output interface 1100, and network interface 1120 to send and receive data to and from each other. However, the method of connecting the processor 1040 and the other components is not limited to bus connection.

[0029] Processor 1040 is a variety of processors such as CPU (Central Processing Unit), GPU (Graphics Processing Unit), and FPGA (Field-Programmable Gate Array). Memory 1060 is main memory implemented using RAM (Random Access Memory), etc. Storage device 1080 is auxiliary storage implemented using hard disk, SSD (Solid State Drive), memory card, or ROM (Read Only Memory), etc.

[0030] The input / output interface 1100 is an interface for connecting the control unit 131 with input / output devices.

[0031] The network interface 1120 is an interface for connecting the control unit 131 to a communication network. This communication network may be, for example, a LAN (Local Area Network) or a WAN (Wide Area Network). The network interface 1120 may connect to the communication network via a wireless connection or a wired connection.

[0032] The storage device 1080 stores program modules that implement each function of the control unit 131. The processor 1040 reads these program modules into the memory 1060 and executes them to implement the functions corresponding to each program module.

[0033] As described above, the gas sample concentration apparatus 100 according to this embodiment allows for precise control of the gas temperature by controlling the position of the piping 120 in the temperature gradient region 110a. This enables precise control of gas concentration.

[0034] [Second Embodiment] Next, a second embodiment will be described. This embodiment is the same as the first embodiment, except for the points described below.

[0035] In this embodiment, the control unit 131 provides feedback using the temperature of the piping 120 or the temperature of the gas flowing through the piping 120. The specific processing flow is described below.

[0036] Figure 7 is a flowchart showing the flow of control by the control unit 131 according to this embodiment for controlling the position of the piping. Note that the flow from step S100 to step S300 is the same as in the first embodiment, so the explanation is omitted.

[0037] In this embodiment, the control unit 131 controls the position of the pipe 120 in step S300 (for example, after 5 seconds or more have elapsed after step S300), and then acquires a measured temperature of the pipe 120 or the temperature of the gas flowing through the pipe 120 (step S400). For example, the measured temperature is acquired from a detection unit including a temperature sensor provided on the outside or inside of the pipe 120. The control unit 131 then calculates the difference between the acquired measured temperature and the target temperature, and determines whether the calculated difference is within a predetermined range (step S500).

[0038] If the difference is within a predetermined range (step S500: YES), the control unit 131 temporarily terminates the control of the position of the pipe 120 and returns to step S100. Then, it periodically acquires the measured temperature and repeats the comparison between the measured temperature and the target temperature (repeats steps S100 to S400). Note that after it is determined in step S500 that the difference is within a predetermined range, the steps from S100 onwards may be repeated after, for example, 1 minute, or after 10 minutes. On the other hand, if the difference is not within a predetermined range (step S500: NO), the control unit 131 returns to step S300 and controls the position of the pipe 120 again. For example, if the measured temperature is higher than the target temperature, the position of the pipe 120 is controlled toward the cold source 110d. Also, if the measured temperature is lower than the target temperature, the position of the pipe 120 is controlled to move away from the cold source 110d. In this case, the position of the pipe 120 is controlled based on the calculated difference.

[0039] As described above, the gas sample concentration apparatus 100 according to this embodiment can accurately control the gas temperature by controlling the position of the piping 120 in the temperature gradient region 110a. This allows for accurate control of gas concentration. Furthermore, according to this embodiment, since the control mechanism 130 performs control including feedback, the gas temperature can be controlled continuously and with greater precision.

[0040] The embodiments of the present invention have been described above with reference to the drawings, but these are merely examples of the present invention, and various other configurations can also be adopted.

[0041] Furthermore, although the flowchart used in the above description shows multiple steps (processes) in order, the execution order of the steps performed in each embodiment is not limited to the order in which they are described. In each embodiment, the order of the illustrated steps can be changed to the extent that it does not impede the content. Also, the above embodiments can be combined to the extent that their contents do not conflict. [Explanation of Symbols]

[0042] 100 Gas Sample Concentrator 110 Container 110a Temperature gradient region 120 Piping 130 Control mechanism 210 Carrier gas inlet 220 Sample introduction section 300 columns 400 detectors 1000 Gas analyzer 1020 Bus 1040 processor 1060 memory 1080 Storage Devices 1100 Input / Output Interface 1120 Network Interface

Claims

1. A container that includes a temperature gradient region, which is a region having a temperature gradient, A pipe that serves as a gas flow path and in which at least a portion is located in the temperature gradient region, A control mechanism that controls the position of the piping in the temperature gradient region according to the target temperature of the gas, A gas sample concentration device, including one.

2. A cold source can be placed in the aforementioned container. In the aforementioned temperature gradient region, the temperature increases as you move away from the cold source. The gas sample concentration apparatus according to claim 1.

3. The cooling source includes a heat exchanger, liquid nitrogen, liquid helium, and at least one of solid carbon dioxide. The gas sample concentration apparatus according to claim 2.

4. Includes a temperature detection unit that detects the temperature of the aforementioned pipe, The control mechanism controls the position of the pipe using the difference between the temperature of the pipe detected by the temperature detection unit and the target temperature. The gas sample concentration apparatus according to claim 1 or 2.

5. Includes a heat source located on the opposite side of the cold source via the temperature gradient region, The gas sample concentration apparatus according to claim 2.

6. A gas sample concentration apparatus according to claim 1 or 2, An analysis unit located downstream of the aforementioned gas sample concentration device, A gas analyzer having the following features.

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