JP2018146369A - Gas concentrating device and gas concentrating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas concentrator and a gas concentrating method capable of suppressing a decrease in detection accuracy of a gas component to be detected contained in a sample gas. SOLUTION: A gas concentrator 1 is arranged in a gas flow path 3 in which a sample gas flows inside and a gas flow path 3, collects a detection target gas component contained in the sample gas, and detects a detection target gas component. The gas collecting unit 5 is provided with a gas collecting unit 5 for concentrating the gas, and a replacement means for replacing the air in the gas collecting unit 5 with nitrogen gas before flowing the concentrated gas component to be detected to the gas detecting device 2. [Selection diagram] Fig. 1

Description

  The present invention relates to a gas concentrating device and a gas concentrating method, and more particularly to a gas concentrating device and a gas concentrating method for concentrating a detection target gas component contained in a sample gas.

  Conventionally, a gas detection device that concentrates a component gas (detection target gas component) contained in a gas (sample gas) is known (see, for example, Patent Document 1).

  The gas detection device described in Patent Document 1 includes a ventilation means for circulating gas through a ventilation section (gas flow path), an adsorbent (gas collection section) for collecting component gas contained in the gas, and a component. A gas detection unit (detection unit) for detecting gas. The gas detection apparatus described in Patent Document 1 includes a first opening / closing means (valve part) and a second opening / closing means (valve part) that seal the adsorbent in order to condense the component gas. And a heating unit for desorbing the component gas from the adsorbent.

  In the gas detection device described in Patent Literature 1, the adsorbent collects the component gas in the gas flowing through the ventilation portion by the ventilation means, and the adsorbent is sealed by the first opening and closing means and the second opening and closing means. Then, the adsorbent is heated by the heating unit. At this time, in the gas detection unit, the component gas adsorbed by the adsorbent is desorbed at a time by the heating of the heating unit, and the concentrated component gas is detected.

JP 2015-197400 A

  However, in the gas detection device described in Patent Document 1, when the component gas collected in the adsorbent is concentrated (heated by the heating unit), the gas around the adsorbent (gas collecting unit), the component gas, It is conceivable that heterogeneous component gases are generated due to this reaction. For this reason, in the gas detection part of the gas detection apparatus of the said patent document 1, there exists a problem that the detection precision of the component gas (detection object gas component) contained in gas (sample gas) will fall.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a gas concentrator capable of suppressing a decrease in detection accuracy of a detection target gas component contained in a sample gas. And providing a gas enrichment method.

  A gas concentrator according to a first aspect of the present invention includes a gas flow path through which a sample gas circulates and a gas flow path that is disposed in the gas flow path and collects a detection target gas component contained in the sample gas. A gas collection unit for concentrating the components and a replacement means for replacing the gas in the gas collection unit with an inert gas before flowing the concentrated detection target gas component to the detection unit.

  As described above, the gas concentrator according to the first aspect of the present invention collects and concentrates the detection target gas component, and before flowing the concentrated detection target gas component to the detection unit, the gas is collected. Substitution means for substituting the gas in the collection part with an inert gas. Thereby, when concentrating the detection target gas component collected in the gas collection unit, the gas in the gas collection unit is replaced with an inert gas by the replacement means, so the gas in the gas collection unit and the detection target Reaction with the gas component can be suppressed. As a result, it is difficult to generate a foreign gas due to the reaction between the gas in the gas collection unit and the gas component to be detected, so that it is possible to suppress a decrease in the detection accuracy of the gas component to be detected contained in the sample gas. Can do.

  In the gas concentrator according to the first aspect, preferably, the gas collection unit includes a gas collection tube for collecting a detection target gas component contained in the sample gas, and a detection target collected in the gas collection tube. A heating unit that desorbs the gas component by heating, and when the detection target gas component is heated by the heating unit, to the upstream side and the downstream side of the detection target gas component collected in the gas collection pipe The valve part which prevents the outflow of is further provided. If comprised in this way, even if the detection target gas component collected in the gas collection pipe is desorbed by the heating unit, it can be prevented from flowing out upstream and downstream from the valve unit. . Thereby, the fall of the density | concentration of the detection object gas component desorbed by the heating part can be suppressed.

  In this case, preferably, after flowing the concentrated detection target gas component to the detection unit, the inert gas is allowed to flow in the gas collection tube and the gas flow path while the gas collection tube is heated by the heating unit. A cleaning means for cleaning the gas collection tube and the valve portion is further provided. If comprised in this way, since an inert gas is poured by the cleaning means in a gas collection pipe and a gas flow path, the detection target gas component which remains in a gas collection pipe, a gas flow path, and a valve part is detected. It can be discharged out of the device. As a result, the remaining amount of the detection target gas component in the gas collection pipe, the gas flow path, and the valve portion can be reduced, so that the detection target gas contained in the sample gas will be detected in the next detection of the detection target gas component. It can suppress that the detection accuracy of a component falls.

  The gas concentrating device according to the first aspect preferably further includes a carrier gas supply unit that supplies an inert gas into the gas channel as a carrier gas for circulating the sample gas in the gas channel, The gas supply unit is configured to also serve as a replacement unit. If comprised in this way, since the carrier gas supply part serves also as a substitution means, it becomes unnecessary to provide the means for supplying an inert gas to a gas collection part separately from a carrier gas supply part. As a result, the configuration of the gas concentrator can be simplified.

  The gas concentration method according to the second aspect of the present invention includes a step of collecting the detection target gas component contained in the sample gas flowing in the gas flow path by the gas collection unit and concentrating the detection target gas component; A step of flowing the concentrated detection target gas component to the detection unit; and a step of replacing the gas in the gas collection unit with an inert gas before flowing the concentrated detection target gas component to the detection unit.

  In the gas concentration method according to the second aspect of the present invention, as described above, the gas in the gas collection unit is replaced with an inert gas before flowing the concentrated detection target gas component to the detection unit. Thereby, when concentrating the detection target gas component collected in the gas collection unit, since the gas in the gas collection unit is replaced with an inert gas, the gas in the gas collection unit and the detection target gas component This reaction can be suppressed. As a result, it is difficult to generate a foreign gas due to the reaction between the gas in the gas collection unit and the gas component to be detected, so that it is possible to suppress a decrease in the detection accuracy of the gas component to be detected contained in the sample gas. Can be obtained.

  In the gas concentration method according to the second aspect, preferably, after the concentrated gas component to be detected is flowed to the detection unit, the gas collection unit is heated, and the inert gas is contained in the gas collection unit and the gas flow path. To clean the inside of the gas collection part and the inside of the gas flow path. With this configuration, the inert gas flows in the gas collection pipe and the gas flow path after flowing the concentrated detection target gas component in the detection section, so that it remains in the gas collection pipe and the gas flow path. The detection target gas component can be discharged. As a result, the remaining amount of the detection target gas component in the gas collection pipe and the gas flow path can be reduced, so that the detection of the detection target gas component contained in the sample gas will be performed in the next detection of the detection target gas component. A decrease in accuracy can be suppressed.

  According to the present invention, as described above, it is possible to suppress a decrease in detection accuracy of the detection target gas component contained in the sample gas.

It is the block diagram which showed the structure of the gas concentrator by one Embodiment of this invention. It is the block diagram which showed the structure of the control part of the gas concentrator by one Embodiment of this invention. Fig.3 (a) is sectional drawing which showed the gas collection part of the state by which the detection target gas component was collected by the adsorbent. FIG. 3B is a cross-sectional view showing the gas collection unit in a state where the detection target gas component is desorbed from the adsorbent. FIG. 3C is a cross-sectional view illustrating the gas collection unit in a state where the detection target gas component is adsorbed on the adsorbent and the detection target gas component is desorbed from the adsorbent. It is the block diagram which showed the sample gas introduction flow path of the gas concentration apparatus by one Embodiment of this invention. It is the block diagram which showed the inert gas introduction flow path of the gas concentration apparatus by one Embodiment of this invention. It is the block diagram which showed the desorption state of the gas concentrator by one Embodiment of this invention. It is the block diagram which showed the detection flow path of the gas concentrator by one Embodiment of this invention. It is the block diagram which showed the cleaning flow path of the gas concentrator by one Embodiment of this invention. It is sectional drawing which showed the internal flow path of the 2nd on-off valve of the gas concentration apparatus by one Embodiment of this invention. It is the flowchart which showed the gas concentration process by the gas concentration apparatus by one Embodiment of this invention. It is the graph which showed the result which detected the sample gas of the same quantity and the same density | concentration concentrated with the gas concentration apparatus by 1st Example of this invention in the gas detection apparatus. It is the graph which showed the result of having detected in the gas detection apparatus the sample gas of different quantity and the same density | concentration which was concentrated with the gas concentration apparatus by 2nd Example of this invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.

  First, with reference to FIGS. 1-9, the whole structure of the gas concentration apparatus 1 by this embodiment of this invention is demonstrated.

(Gas concentrator)
As shown in FIGS. 1 and 2, the gas concentrator 1 is configured to concentrate the detection target gas component G1 (see FIG. 3) and supply the concentrated detection target gas component G1 to the gas detection device 2. Yes. Specifically, the gas concentrating device 1 includes a gas flow path 3, a carrier gas supply unit 4, a gas collection unit 5, a sample gas supply unit 6, and a control unit 7. The gas detector 2 is an example of the “detector” in the claims.

  The gas flow path 3 connects the carrier gas supply unit 4, the gas collection unit 5, the sample gas supply unit 6, and the gas detection device 2. In the gas flow path 3, the carrier gas supplied by the carrier gas supply unit 4 circulates inside. In the gas flow path 3, the sample gas supplied by the sample gas supply unit 6 circulates inside. The gas flow path 3 includes a first flow path 31 from the sample gas inlet (sample gas IN) to the gas collection section 5, and a second flow path 32 from the carrier gas supply section 4 to the gas collection section 5. Is included. The gas flow path 3 includes a third flow path 33 from the gas collection unit 5 to the sample gas supply unit 6 and a fourth flow path 34 from the sample gas supply unit 6 to the first outlet (OUT1). . The gas flow path 3 includes a fifth flow path 35 from the gas collection unit 5 to the second outlet (OUT2). Further, the gas flow path 3 includes a sixth flow path 36 from the gas collection unit 5 to the gas detection device 2.

  As shown in FIG. 1, a valve portion 8 and a switching valve portion 9 are arranged in the gas flow path 3. The valve unit 8 is configured to flow the sample gas and the carrier gas in a normal state (displayed in white) and to block the gas flow path 3 by applying a signal from the control unit 7. The switching valve unit 9 is configured to allow a sample gas or a carrier gas to flow on one side during normal times (indicated by white). Further, the switching valve unit 9 switches the gas flow direction by applying a signal from the control unit 7 (hereinafter, displayed in black at the time of switching) so that the sample gas or the carrier gas flows on the other side. It is configured.

  As shown in FIG. 1, the valve unit 8 includes a first on-off valve 81 and a second on-off valve 82. As described above, the valve unit 8 has a function of blocking the flow of the sample gas and the carrier gas upstream or downstream in the vicinity of the gas collection unit 5. As shown in FIG. 9, the second on-off valve 82 has a meandering internal flow path 83, a shaft 84, and a diaphragm 85. In the second on-off valve 82, when the shaft 84 advances and retreats in the X direction (two-dot chain line in FIG. 9), the diaphragm 85 expands and contracts (two-dot chain line in FIG. 9), and the internal flow path 83 is opened and closed.

  The switching valve unit 9 includes a first switching valve 91, a second switching valve 92, and a third switching valve 93. The first switching valve 91 is configured to flow the carrier gas through the second flow path 32 during normal operation, and to flow the sample gas through the first flow path 31 during switching. The second switching valve 92 is configured to flow a carrier gas through the fifth flow path 35 or the sixth flow path 36 during normal operation and to flow a sample gas through the third flow path 33 during switching. The third switching valve 93 is configured to flow the carrier gas through the sixth flow path 36 during normal operation and to flow the carrier gas through the fifth flow path 35 during switching.

  The carrier gas supply unit 4 is configured to supply a carrier gas, which is an inert gas, into the gas flow path 3 in order to circulate the sample gas in the gas flow path 3. Specifically, the carrier gas supply unit 4 includes a storage unit 41, a first flow rate control unit 42, and a first buffer 43. The storage unit 41 stores nitrogen gas that is an inert gas. The first flow rate control unit 42 is configured to adjust the flow rate of nitrogen gas supplied to the gas flow path 3. The first buffer 43 is configured to temporarily store the nitrogen gas supplied from the first flow rate controller 42 in order to keep the pressure of the nitrogen gas supplied to the gas flow path 3 constant.

  The sample gas supply unit 6 is configured to introduce a part of the air around the gas concentrating device 1 as a sample gas from the inlet (sample gas IN) and supply it into the gas flow path 3. Specifically, the sample gas supply unit 6 includes a pump 61, a second flow rate control unit 62, and a second buffer 63. The pump 61 is configured to circulate through the gas flow path 3 by sucking the sample gas supplied into the gas flow path 3. The second buffer 63 is configured to temporarily store the sample gas in order to keep the pressure of the sample gas sucked by the pump 61 constant. The second flow rate control unit 62 is configured to adjust the flow rate of the sample gas flowing through the gas flow path 3.

  The gas collection unit 5 is disposed in the gas flow path 3 and collects the detection target gas component G1 (toluene, methylbenzene, metaxylene, orthoxylene) contained in the sample gas and concentrates the detection target gas component G1. Is configured to do. Specifically, as shown in FIG. 3, the gas collection unit 5 includes a gas collection tube 51, a heating unit 52, and a heat insulating material 53. As shown in FIG. 3A, the gas collection tube 51 is configured to collect the detection target gas component G1 contained in the sample gas by the adsorbent 54 filled in the internal space. The gas collection tube 51 is made of metal and is formed in a cylindrical shape. The adsorbent 54 is formed of carbon nanotubes and has a function of collecting the detection target gas component G1.

  As shown in FIG. 3B, the heating unit 52 has a function of desorbing from the adsorbent 54 by heating the detection target gas component G <b> 1 collected in the gas collection tube 51. The heating unit 52 is attached to the gas collection tube 51 by being wound around the outer peripheral surface of the gas collection tube 51. The heating unit 52 heats the adsorbent 54 to about 270 ° C. via the gas collection tube 51. The heating unit 52 includes a film heater for heating the detection target gas component G1. The heat insulating material 53 has a function of efficiently conducting the heat generated by the heating unit 52 to the gas collection tube 51. The heat insulating material 53 is attached to the gas collection tube 51 by being wound around the outer peripheral surface of the heating unit 52. The heat insulating material 53 has a silicon sheet. Here, the desorption state in which the adsorbent 54 desorbs the detection target gas component G1 due to the heating of the heating unit 52 is the detection target gas component G1 adsorbed on the adsorbent 54 as shown in FIG. As shown in FIG. 3C, many of the detection target gas components G1 adsorbed on the adsorbent 54 are desorbed and, on the other hand, are detected on the adsorbent 54. This is a broad concept including a state where the gas component G1 is adsorbed.

  The gas concentrator 1 according to the present embodiment is configured to replace the air in the gas collection pipe 51 with nitrogen gas, which is an inert gas, before the detection target gas component G1 is heated by the heating unit 52. . Thereby, in the gas concentrator 1, when the gas collection pipe 51 is heated by the heating unit 52 and the detection target gas component G1 is desorbed from the adsorbent 54, the chemistry of the detection target gas component G1 and oxygen in the air is performed. Generation of extraneous gas components due to the reaction is suppressed. Hereinafter, the control means for replacing the air in the gas collection pipe 51 with nitrogen gas in the gas concentrator 1 will be described. Air is an example of “gas” in the claims.

  As shown in FIG. 2, the control unit 7 has a function of controlling the sample means 71, the replacement means 72, the detachment means 73, the detection means 74, and the cleaning means 75. Specifically, the control unit 7 is electrically connected to the pump 61, the valve unit 8, the switching valve unit 9, the first flow rate control unit 42, the second flow rate control unit 62, and the heating unit 52, and controls each of them. ing.

  As shown in FIG. 4, the sample means 71 causes the sample gas to flow in the order of the first flow path 31, the third flow path 33, and the fourth flow path 34, and collects the detection target gas component G <b> 1 in the gas collection unit 5. It is configured to let you. Specifically, as shown in FIG. 2, the sample means 71 includes a pump 61, a switching valve unit 9 (first switching valve 91 and second switching valve 92), and a second flow rate control unit 62. . As shown in FIG. 4, the control means 7 causes the sample means 71 to switch the first switching valve 91 and the second switching valve 92 to the state at the time of switching and to flow a sample gas through the sample gas introduction channel. Form. As a result, the sample gas can flow through the first flow path 31 by the suction of the pump 61, and the gas collection unit 5 can adsorb the detection target gas component G <b> 1. Further, the sample means 71 adjusts the flow rate of the sample gas flowing in the sample gas introduction flow path by the second flow rate control unit 62.

  As shown in FIG. 5, the replacement unit 72 is configured to flow the concentrated detection target gas component G1 to the gas detection device 2 (see FIG. 1) (before heating the detection target gas component G1 collected by the adsorbent 54). ), The air in the gas collection unit 5 is replaced with nitrogen gas. Specifically, as shown in FIG. 2, the replacement unit 72 includes a switching valve unit 9 (third switching valve 93) and a first flow rate control unit 42. As shown in FIG. 5, the replacement unit 72 by the control unit 7 switches the third switching valve 93 to the state at the time of switching and collects the gas to be detected G2 before flowing the concentrated detection target gas component G <b> 1. An inert gas introduction channel, which is a channel for replacing the air in the pipe 51 with nitrogen gas, is formed. Thus, the carrier gas supply unit 4 allows nitrogen gas to flow through the second flow path 32 to replace the air in the gas collection pipe 51 of the gas collection unit 5 with nitrogen gas. The replacement means 72 adjusts the flow rate of nitrogen gas flowing in the inert gas introduction flow path by the first flow rate control unit 42. As described above, the replacement unit 72 uses the carrier gas supply unit 4 to replace the air in the gas collection unit 5 with nitrogen gas, and the carrier gas supply unit 4 is configured to also serve as the replacement unit 72. ing.

  As shown in FIG. 6, the desorption means 73 replaces the gas in the gas collection pipe 51 with nitrogen by the replacement means 72, and then detects the detection target gas component G <b> 1 collected by the adsorbent 54 from the adsorbent 54. It is configured to desorb. Specifically, as shown in FIG. 2, the detaching means 73 includes a valve unit 8 (first on-off valve 81 and second on-off valve 82) and a heating unit 52. As shown in FIG. 6, the detaching means 73 by the control unit 7 uses the first on-off valve 81 and the second on-off valve 82 to block each of the second flow path 32 and the fifth flow path 35 and heat it. The gas collection tube 51 is heated by the unit 52. The desorption means 73 is configured such that when the detection target gas component G1 is heated by the heating unit 52, the detection target gas component G1 collected in the gas collection pipe 51 is upstream of the first on-off valve 81, and The second on-off valve 82 has a function of preventing the outflow to the downstream side. In this way, the desorption means 73 desorbs the detection target gas component G1 collected in the adsorbent 54 from the adsorbent 54 (see FIG. 3B) and desorbs it in the gas collection tube 51. By staying the detected gas component G1 detected, it is possible to concentrate the detected gas component G1.

  As shown in FIG. 7, the detection means 74 is configured to flow the detection target gas component G <b> 1 concentrated in the gas detection device 2 and cause the gas detection device 2 to detect the detection target gas component G <b> 1. Specifically, the detection means 74 includes a first flow rate control unit 42 as shown in FIG. As shown in FIG. 7, the detection means 74 by the control unit 7 forms a detection flow path for flowing the detection target gas component G <b> 1 to the gas detection device 2 without switching the switching valve unit 9. The detection means 74 adjusts the flow rate of nitrogen gas flowing in the detection flow path by the first flow rate control unit 42. The detection target gas component G1 desorbed from the adsorbent 54 can be detected by the gas detection device 2.

  As shown in FIG. 8, the cleaning unit 75 flows the gas detection pipe G1 to the gas detector 2 (see FIG. 1). Nitrogen gas is allowed to flow through the passage 3 and the gas collection pipe 51, and the gas flow path 3, the gas collection pipe 51, the valve portion 8 and the switching valve portion 9 are cleaned. Specifically, as shown in FIG. 2, the cleaning means 75 includes a switching valve unit 9 (third switching valve 93), a heating unit 52, and a first flow rate control unit 42. As shown in FIG. 8, the control means 7 causes the cleaning means 75 to switch to the state at the time of switching using the third switching valve 93, and to detect remaining in the gas flow path 3 and the gas collection pipe 51. A cleaning flow path that is a flow path for discharging the target gas component G1 is formed.

  As shown in FIG. 9, the cleaning means 75 causes the nitrogen gas to flow through the cleaning flow path, thereby detecting the detection target gas components G1 (D1 to D8) remaining in the flow path of the nitrogen gas in the second on-off valve 82. It has a function to discharge.

  The cleaning means 75 adjusts the flow rate of nitrogen gas flowing in the cleaning flow path by the first flow rate control unit 42. The cleaning means 75 remains in the gas flow path 3 and the gas collection pipe 51 by controlling the first flow rate control unit 42 so that the initial flow rate of the nitrogen gas is larger than the flow rate at other time points. It is possible to improve the discharge efficiency of the detection target gas component G1.

(Gas detection device)
As shown in FIG. 1, the gas detection device 2 is configured to detect the detection target gas component G <b> 1 concentrated by the gas concentration device 1. Specifically, the gas detection device 2 includes a detection unit 20 that detects each of the plurality of detection target gas components G1 and a separation column that varies the timing at which each of the plurality of detection target gas components G1 passes through the detection unit 20. 21.

(Gas concentration treatment)
Next, with reference to FIG. 10, the gas concentration process (gas concentration method) of the gas concentration apparatus 1 by one Embodiment of this invention is demonstrated.

  In the gas concentration process of the gas concentrator 1, the gas channel 3 is switched to the sample gas introduction channel (see FIG. 4) using the sample means 71 in step S1. In step S2, the sample gas is sucked by the pump 61 of the sample gas supply unit 6, and the sample gas is caused to flow into the sample gas introduction channel. In step S3, the detection target gas component G1 is collected by the adsorbent 54 in the gas collection tube 51 in the sample gas introduction channel.

  In step S4, the gas passage 3 is switched to the inert gas introduction passage (see FIG. 5) using the replacement means 72. In step S5, nitrogen gas is caused to flow through the inert gas introduction channel by the carrier gas supply unit 4, and the air in the gas collection pipe 51 is replaced with nitrogen gas. In step S6, the valve 8 is closed using the desorption means 73 in the gas flow path 3 (see FIG. 6). In step S7, the gas collection tube 51 is heated by the heating unit 52, thereby desorbing the detection target gas component G1 from the adsorbent 54 and concentrating the detection target gas component G1. In step S <b> 8, the gas collection pipe 51 is opened by opening the valve unit 8 using the desorption means 73. Thus, the detection target gas component G1 desorbed from the adsorbent 54 can flow downstream from the second on-off valve 82.

  In step S9, the gas flow path 3 is switched to the detection flow path (see FIG. 7) using the detection means 74. In step S <b> 10, nitrogen gas is caused to flow through the detection flow path using the carrier gas supply unit 4, and the concentrated detection target gas component G <b> 1 is caused to flow into the gas detection device 2. Thereby, the gas detection apparatus 2 detects the detection target gas component G1 as shown in FIG. 11 and FIG.

  In step S11, the gas channel 3 is switched to the cleaning channel (see FIG. 8) using the cleaning means 75. In step S12, while the gas collecting tube 51 is heated by the heating unit 52 using the cleaning means 75, nitrogen gas is allowed to flow in the gas collecting tube 51 and the cleaning flow channel, whereby the gas flow channel 3 and the gas collecting gas are collected. The inside of the pipe 51 is cleaned. Then, the gas concentration process of the gas concentration apparatus 1 is complete | finished.

(Effect of this embodiment)
In the present embodiment, the following effects can be obtained.

  In the present embodiment, as described above, the gas concentrator 1 collects and concentrates the detection target gas component G1 and the concentrated gas to be detected G1 to the detection unit 20 before flowing the detection target gas component G1. And replacement means 72 for replacing the gas in the gas collection part 5 with nitrogen gas. Thereby, when concentrating the detection target gas component G1 collected in the gas collection unit 5, the gas in the gas collection unit 5 is replaced by nitrogen gas by the replacement unit 72. The reaction between the gas inside and the detection target gas component G1 can be suppressed. As a result, since a heterogeneous gas is less likely to be generated due to a chemical reaction between the gas in the gas collection unit 5 and the detection target gas component G1, a decrease in detection accuracy of the detection target gas component G1 contained in the sample gas is suppressed. can do.

  Further, in the present embodiment, as described above, even if the detected gas component G1 collected in the adsorbent 54 in the gas collection pipe 51 is desorbed from the adsorbent 54 due to the heating of the heating unit 52. In the gas flow path 3, it is possible to suppress the outflow to the upstream side of the first on-off valve 81 and the downstream side of the second on-off valve 82. Thereby, the fall of the density | concentration of the detection target gas component G1 desorbed by the heating part 52 can be suppressed.

  Further, in the present embodiment, as described above, after the concentrated detection target gas component G1 is flowed to the gas detection device 2, the gas collection pipe 51 and the gas flow path 3 heated by the heating unit 52 are placed in the gas detection device 2. Nitrogen gas is supplied by the cleaning means 75. Thereby, the detection target gas component G1 remaining in the gas collection pipe 51, the gas flow path 3, and the valve portion 8 can be discharged from the second outlet. As a result, since the remaining amount of the detection target gas component G1 in the gas collection pipe 51, the gas flow path 3, the valve portion 8, and the switching valve portion 9 can be reduced, the next detection target gas component G1 is detected. And the fall of the detection precision of the detection target gas component G1 contained in sample gas can be suppressed.

  In the present embodiment, as described above, since the carrier gas supply unit 4 also serves as the replacement unit 72, a unit for supplying nitrogen gas to the gas collection pipe 51 is provided separately from the carrier gas supply unit 4. This is unnecessary, and the configuration of the gas concentrator 1 can be simplified.

  In the present embodiment, as described above, the gas in the gas collection tube 51 is replaced with nitrogen gas before flowing the concentrated detection target gas component G1 to the gas detection device 2. Thus, when the detection target gas component G1 collected by the adsorbent 54 of the gas collection tube 51 is concentrated, the gas in the gas collection tube 51 is replaced with nitrogen gas. The reaction between the gas inside and the detection target gas component G1 can be suppressed. As a result, the gas in the gas collection pipe 51 and the detection target gas component G1 are less likely to generate a foreign gas, thereby suppressing a decrease in detection accuracy of the detection target gas component G1 contained in the sample gas. Gas enrichment methods that are possible.

  In the present embodiment, as described above, after the concentrated detection target gas component G <b> 1 is flowed to the gas detection device 2, nitrogen gas is flowed into the gas collection pipe 51 and the gas flow path 3. Thereby, the detection target gas component G1 remaining in the gas collection pipe 51 and the gas flow path 3 can be discharged from the second outlet. As a result, since the remaining amount of the detection target gas component G1 in the gas collection pipe 51 and the gas flow path 3 can be reduced, a decrease in detection accuracy of the detection target gas component G1 contained in the sample gas is suppressed. be able to.

[Example]
Next, referring to FIG. 11 and FIG. 12, using the gas concentrating device 1 and the gas detecting device 2 of the above embodiment, the actual predetermined concentrations of toluene, methylbenzene, metaxylene and orthoxylene are included. An experiment in which mixing gas is detected will be briefly described.

<First embodiment>
First, the first embodiment will be described. In the first embodiment, even when the mixing gas (sample gas) is concentrated and detected a plurality of times (four times), the detection target gas component G1 concentrated by the gas concentrator 1 is accurately detected in the gas detector 2. The purpose is to check whether it can be detected. The total amount of the mixing gas was 400 ml, and the concentrations of toluene, methylbenzene, metaxylene, and orthoxylene, which are detection target gas components G1 of the mixing gas, were set to 100 ppb. Such mixing gas was measured four times. Specifically, the mixing gas was concentrated using the gas concentrating device 1 and the detection target gas component G1 concentrated using the gas detecting device 2 was detected. Thereafter, in the gas concentrator 1, cleaning is performed by the cleaning means 75, and the mixing gas having the same concentration and the same amount is condensed using the gas concentrator 1 and concentrated using the gas detector 2. Component G1 was detected. These concentration by the gas concentrator 1, detection by the gas detector 2, and cleaning by the cleaning means 75 were performed a total of four times, and the respective detection results were compared.

(Measurement result)
FIG. 11 shows the first to fourth mixing gas detection results.

  As a detection result, the detection result of the gas detection device 2 detects the same waveform in any of the first to fourth times. This indicates that the concentrations of concentrated toluene, methylbenzene, meta-xylene and ortho-xylene were similar even when the gas concentrator 1 was continuously used, and as a result, the detection was reproducible. It was confirmed that there was. Further, in the gas concentrator 1, it was confirmed that the toluene, methylbenzene, metaxylene and orthoxylene remaining in the gas flow path 3 and the gas collection pipe 51 can be discharged every time by the cleaning means 75. .

<Second embodiment>
Next, a second embodiment will be described. The second embodiment is intended to examine whether or not the amount of the detection target gas component G1 detected by the gas detection device 2 differs depending on the different total amounts of a plurality (three types) of mixing gases. Each of the plurality of mixing gases has a total amount of 1600 ml, 800 ml, and 400 ml, and the concentrations of toluene, methylbenzene, metaxylene, and orthoxylene, which are detection gas components G1 of the mixing gas, were set to 100 ppb. A plurality of such mixing gases were measured.

(Measurement result)
FIG. 12 shows the detection results of three types of mixing gases having different total amounts.

  As detection results, the detection results of the three types of mixing gas detect different waveforms in the detection results of the gas detection device 2. That is, in the detection results of the three types of mixing gas, the detected voltages of detected toluene, methylbenzene, meta-xylene and ortho-xylene decrease at a constant rate as the total amount of mixing gas decreases. Thereby, even if the amount of the mixing gas was reduced, it was confirmed that an accurate amount could be measured by concentrating toluene, methylbenzene, metaxylene and orthoxylene using the gas concentrator 1.

(Modification)
The embodiments and examples disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments and examples but by the scope of claims for patent, and includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above embodiment, the desorption means 73 includes the heating unit 52 for desorbing the detection target gas component G1 from the adsorbent 54, but the present invention is not limited to this. For example, the desorption means may have a compression unit that compresses the air in the gas collection tube and raises the temperature in the gas collection tube.

  Moreover, in the said embodiment, although the carrier gas supply part 4 serves as the replacement means 72 for replacing the air in the gas collection pipe | tube 51 with nitrogen gas, this invention is not limited to this. In the present invention, the carrier gas supply unit does not have to serve as a replacement unit. That is, in addition to the carrier gas supply unit that supplies the carrier gas to the gas flow path, an inert gas supply unit that replaces the air in the gas collection tube with an inert gas may be provided.

  Further, in the above embodiment, the carrier gas supply unit 4 cleans the detection target gas component G1 remaining in the gas flow path 3 and the gas collection pipe 51, so Although it also serves as the cleaning means 75 that flows through the collecting pipe 51, the present invention is not limited to this. In the present invention, the carrier gas supply unit does not have to serve as the cleaning unit. That is, in addition to the carrier gas supply unit that supplies the carrier gas to the gas channel, the inert gas supply unit that supplies the inert gas to the gas channel in order to clean the remaining sample gas in the gas collection tube May be provided.

  Moreover, in the said embodiment, although the heating part 52 is heating the gas collection pipe | tube 51 by about 270 degreeC, this invention is not limited to this. In the present invention, the heating unit may heat the gas collection tube at a temperature lower than 270 ° C., or may heat the gas collection tube at a temperature higher than 270 ° C.

  Moreover, in the said embodiment, although inert gas is nitrogen gas, this invention is not limited to this. For example, it may be an inert gas such as argon gas or helium gas that has poor reactivity.

  Moreover, in the said embodiment, although the detection object gas component G1 is toluene, methylbenzene, metaethylene, and orthoxylene, this invention is not limited to this. For example, the detection target gas component may be ammonia, hydrogen sulfide, or the like.

  Moreover, in the said Example, although sample gas is mixing gas containing four types of detection target gas components G1, this invention is not limited to this. In the present invention, the sample gas may contain 1 to 3 types or 5 or more types of detection target gas components.

  Moreover, in the said embodiment, although the adsorbent 54 is a carbon nanotube, this invention is not limited to this. For example, the adsorbent may be an adsorbent such as silica gel or zeolite that can adsorb the detection target gas component and can desorb the detection target gas component by heating the heating unit.

  Moreover, in the said embodiment, although the heating part 52 is a film heater, this invention is not limited to this. For example, the heating part may be a nichrome wire or the like.

  Moreover, in the said embodiment, although the heat insulating material 53 is a silicon sheet, this invention is not limited to this. For example, the heat insulating material may be an elastomer sheet or the like.

  Moreover, in the said embodiment, although the collection of the detection object gas component G1 to the adsorbent 54 is performed at normal temperature, this invention is not limited to this. For example, a Peltier element may be attached to the collection tube, and the detection target gas component may be collected at a temperature lower than room temperature to improve the collection efficiency.

  Further, in the above embodiment, the cleaning unit 75 heats the gas collection pipe 51 by the heating unit 52 and opens the first on-off valve 81 and the second on-off valve 82 and opens the gas passage 3 and the gas trap. Although nitrogen gas is flowed into the collecting pipe 51 and the gas flow path 3, the gas collecting pipe 51, the valve portion 8 and the switching valve portion 9 are cleaned, the present invention is not limited to this. In the present invention, nitrogen gas may flow into the gas flow path 3 and the gas collection pipe 51 while opening and closing each of the first on-off valve 81 and the second on-off valve 82. Thereby, it is possible to facilitate the discharge of the detection target gas component G1 remaining in the dead space in the first on-off valve 81 and the second on-off valve 82.

  In the above-described embodiment, for convenience of explanation, the processing operation of the control unit 7 has been described using a flow-driven flowchart that performs processing in order along the processing flow, but the present invention is not limited to this. In the present invention, the processing operation of the control unit 7 may be performed by event-driven (event-driven) processing that executes processing in units of events. In this case, it may be performed by a complete event drive type or a combination of event drive and flow drive.

1 Gas concentrator 2 Gas detector (detector)
3 Gas flow path 4 Carrier gas supply unit 5 Gas collection unit 7 Control unit 8 Valve unit 51 Gas collection tube 52 Heating unit 72 Replacement unit 75 Cleaning unit G1 Gas component to be detected

Claims (6)

A gas flow path through which the sample gas flows;
A gas collecting part that is arranged in the gas flow path and collects the detection target gas component contained in the sample gas and concentrates the detection target gas component;
A gas concentrating apparatus comprising: a replacement unit that replaces the gas in the gas collection unit with an inert gas before flowing the concentrated detection target gas component to the detection unit. The gas collection unit is desorbed by heating a gas collection tube that collects the detection target gas component contained in the sample gas, and the detection target gas component collected in the gas collection tube A heating part
The heating device further comprises a valve unit that prevents the detection target gas component collected in the gas collection pipe from flowing out to the upstream side and the downstream side when the detection target gas component is heated by the heating unit. The gas concentrator according to 1.   After flowing the concentrated detection target gas component to the detection unit, the inert gas is allowed to flow through the gas collection tube and the gas flow path while heating the gas collection tube by the heating unit. The gas concentrator according to claim 2, further comprising: a cleaning unit that cleans the gas collection pipe and the valve unit. As a carrier gas for circulating the sample gas in the gas flow path, further comprising a carrier gas supply part for supplying the inert gas into the gas flow path,
The gas concentration apparatus according to any one of claims 1 to 3, wherein the carrier gas supply unit is configured to also serve as the replacement unit. Collecting the detection target gas component contained in the sample gas flowing in the gas flow path by the gas collection unit, and concentrating the detection target gas component;
Flowing the detection target gas component concentrated in the detection unit;
Replacing the gas in the gas collection unit with an inert gas before flowing the concentrated gas component to be detected to the detection unit.   After flowing the concentrated detection target gas component to the detection unit, the gas collection unit is heated, and the inert gas is flowed into the gas collection unit and the gas flow path, so that the gas collection is performed. The gas concentration method according to claim 5, further comprising a step of cleaning the inside of the unit and the inside of the gas flow path.

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