JP6675829B2 - Gas analyzer and method for adjusting gas analyzer - Google Patents

Description

  The present invention relates to a gas analyzer for separating a sample carried by a carrier gas by a column and detecting an output of at least one separated gas component, and a method for adjusting the same.

  In a gas chromatograph as a gas analyzer of this type, a gas component contained in a sample is identified based on a peak position (a time when a peak appears) of each gas component separated by a column. Therefore, in order to perform highly accurate analysis, it is necessary to always keep the output peak position of the target gas component constant. However, when the temperature of the column changes, the peak position of the output in the detected gas component changes, but it is inevitable that the temperature of the column changes to some extent due to heat generation inside the device. For this reason, in the conventional gas analyzer, it was essential to control the temperature of the column by the heater.

  However, there is a demand for downsizing of this type of gas analyzer, for example, in order to make it portable or easy to handle, and providing a heater makes it difficult to downsize it.

  A gas analyzer and a method for adjusting the gas analyzer that can accurately detect the output of an arbitrary gas component without using a heater are desired.

The gas analyzer according to the present invention,
A gas analyzer without a heater for separating a sample carried by a carrier gas by a column, detecting an output of at least one separated gas component, and controlling a temperature of the column ,
A storage unit that stores in advance the relationship between the column temperature and the flow rate of the carrier gas for keeping the output peak position in the target gas component constant.
A temperature sensor for measuring the temperature of the column,
A flow controller configured to adjust a flow rate of the carrier gas according to a temperature measured by the temperature sensor based on the stored relationship.

  The inventor has found that even if the temperature of the column changes and the peak position (time during which the peak appears) of the output of the target gas component changes, the peak position can be changed by changing the flow rate of the carrier gas accordingly. Was found to be able to be kept constant. That is, since the peak position changes not only with the temperature of the column but also with the flow rate of the carrier gas, the change in the peak position due to the temperature change is offset by the change in the peak position due to the change in the flow rate of the carrier gas. For example, it has been found that the peak position of the output of the target gas component can always be kept constant irrespective of the temperature change of the column.

  Then, when a peak appears at that position, the peak position at which the target gas component is to be detected in the sample is determined, and the peak of the output of the target gas component is always at that position. If the relationship between the temperature of the column and the flow rate of the carrier gas, which will appear in the above, is determined in advance, the apparatus can be operated while maintaining the relationship between the temperature and the flow rate, without controlling the temperature by the heater. The apparatus can be operated with the peak position for detecting the presence of the gas component kept constant.

  The above configuration is based on the above knowledge, and stores the relationship between the column temperature and the flow rate of the carrier gas for keeping the output peak position at the target gas component constant, and based on this relationship, The flow rate of the carrier gas is controlled from the temperature of the column measured by the temperature sensor so that the peak position becomes constant. Thus, the output of any gas component can be detected with high accuracy without using a heater. Further, since there is no need to use a heater, the size of the apparatus can be reduced by the amount of the heater, and further, the power consumed by the heater can be reduced, and energy can be saved.

  Hereinafter, preferred embodiments of the present invention will be described. However, the scope of the present invention is not limited by the following preferred embodiments.

  As one aspect, a pump capable of adjusting a flow rate of the introduced carrier gas by adjusting an applied voltage, and a differential pressure sensor for measuring a pressure of the introduced carrier gas, The flow controller controls the voltage applied to the pump to correspond to a target flow rate of the carrier gas based on a table indicating a correspondence relationship between the pressure measured by the differential pressure sensor and the voltage applied to the pump. Pressure is adjusted to a voltage to be measured by the differential pressure sensor, and the flow rate of the carrier gas is adjusted, and the pressure measured by the differential pressure sensor at startup and the pressure applied to the pump are adjusted. When the voltage is different from the correspondence shown in the table, the table is preferably corrected based on the relationship between the pressure and the voltage at the time of starting. It is.

  According to this configuration, based on the table indicating the correspondence between the pressure measured by the differential pressure sensor and the voltage applied to the pump, the pressure corresponding to the flow rate of the carrier gas is reduced to the voltage value measured by the differential pressure sensor. Adjust the voltage applied to the pump. As described above, the flow rate of the carrier gas is adjusted using the differential pressure sensor that requires a smaller space than the flow rate sensor, so that the size of the apparatus can be reduced. However, in this method, when the pressure measured by the differential pressure sensor and the voltage applied to the pump are different from the correspondence shown in the table at the time of startup due to some trouble such as foreign matter entering the pump, the table is not used. Even if the required voltage is applied to the pump, the desired flow rate of the carrier gas cannot be obtained. On the other hand, according to this configuration, even if the pressure measured by the differential pressure sensor and the voltage applied to the pump differ from the correspondence shown in the table, the difference between the pressure at startup and the pressure Since the table is corrected based on the relationship with the voltage, accurate flow rate control of the carrier gas can be performed.

The adjustment method of the gas analyzer according to the present invention,
A method for adjusting a gas analyzer that does not include a heater that controls a temperature of a column by separating a sample carried by a carrier gas by a column and detecting an output of at least one separated gas component,
Determine the relationship between the temperature of the column and the flow rate of the carrier gas to make the peak position of the output in the gas component of interest constant,
Measuring the temperature of the column,
The flow rate of the carrier gas is adjusted according to the temperature of the column measured by a temperature sensor based on the obtained relationship.

  According to this configuration, the same functions and effects as those of the above-described gas analyzer according to the present invention can be obtained.

Configuration diagram of gas analyzer The figure which shows the control which the flow control part performs Figure showing another embodiment

  A gas analyzer according to the present invention will be described with reference to the drawings. The analyzer 1 according to the present embodiment is a gas analyzer that separates a sample carried by a carrier gas by a column 5 and detects an output of at least one separated gas component. Then, the temperature of the column 5 is measured with the storage unit 9 in which a table indicating the relationship between the temperature of the column 5 and the flow rate of the carrier gas for keeping the peak position of the output of the target gas component constant is stored. And a temperature sensor 6. Further, a flow control unit 3 is provided that adjusts the flow rate of the carrier gas according to the temperature measured by the temperature sensor 6 based on the relationship stored in the storage unit. Thus, the output of any gas component can be detected with high accuracy without using a heater. Hereinafter, the analyzer 1 according to the present embodiment will be described in detail.

  As shown in FIG. 1, the analyzer 1 according to the present embodiment includes a suction-type pump 2, a flow controller 3 for controlling the flow rate of the carrier gas sucked from the pump 2, and a carrier gas sucked from the pump 2. An introduction part 4 into which a sample to be analyzed is introduced while being introduced, a column 5 for separating a sample gas carried by a carrier gas, a temperature sensor 6 for measuring a column temperature, and a concentration of a gas component separated by the column 5 A sensor 7 that generates an output based on the above, a determination unit 8 that performs various analyzes such as determination of a gas component contained in the sample gas from an output signal of the sensor 7, and a control by the flow control unit 3 and various analyzes in the determination unit 8. There is provided a storage unit 9 for storing a database including an algorithm to be performed and various data for the algorithm.

  In the analyzer 1, the sample to be analyzed, which is injected from the introduction unit 4, is passed through the column while the flow rate of the carrier gas introduced by the pump 2 is controlled by the flow rate control unit 3. This separates each gas component in the sample. Then, the sensor 7 generates an output corresponding to the concentration of each gas component, and the determination unit 8 detects the output of at least one gas component separated. More specifically, the determination unit 8 determines a gas component to be analyzed in advance and uses the analysis algorithm stored in the storage unit to correspond to the gas component to be analyzed based on the output from the sensor 7. It is determined whether or not the sample contains a gas to be analyzed based on whether a peak is generated.

  Here, the adjustment of the flow rate by the flow rate control unit 3 will be described. First, the pump 2 can adjust the flow rate of the carrier gas introduced into the introduction unit 4 by adjusting the applied voltage. Further, the analyzer 1 is provided with a differential pressure sensor (not shown) for measuring the pressure of the introduced carrier gas. Then, a pressure-voltage table indicating the correspondence between the pressure measured by the differential pressure sensor and the voltage applied to the pump 2 is stored in the database of the storage unit 9. Then, based on the pressure-voltage table, the flow control unit 3 adjusts the voltage applied to the pump 2 to a voltage at which the pressure corresponding to the target flow rate of the carrier gas is measured by the differential pressure sensor. Thus, the flow rate of the carrier gas is adjusted. As described above, the flow rate of the carrier gas is adjusted using the differential pressure sensor that requires a smaller space than the flow rate sensor, so that the size of the apparatus can be reduced.

  In addition, when the pressure measured by the differential pressure sensor at the time of starting the analyzer 1 and the voltage applied to the pump 2 are different from the correspondence shown in the pressure-voltage table, the flow control unit 3 The pressure-voltage table is corrected based on the relationship with the voltage. To explain, according to the pressure-voltage table, it is assumed that the pressure P must be measured with respect to the voltage V, but a different pressure P ′ is measured with respect to the voltage V at startup. Then, the flow control unit 3 varies the voltage applied to the pump 2 to obtain a voltage V ′ at which the pressure P is measured, and further obtains a difference ΔV between the voltage V ′ and the voltage V on the pressure-voltage table. = V'-V). Note that this ΔV indicates that in order for the pressure P to be measured by the differential pressure sensor, a voltage larger by ΔV than the voltage V shown in the pressure-voltage table must be applied to the pump 2. Then, the flow rate controller 3 corrects the pressure-voltage table by using ΔV to uniformly increase the value of each voltage corresponding to each pressure value in the pressure-voltage table by ΔV. By correcting in this manner, accurate flow control of the carrier gas can be performed.

  Then, in the analyzer 1 according to the present embodiment, the database of the storage unit 9 stores, for the gas component to be analyzed, the column temperature and the carrier gas flow rate for keeping the output peak position in the gas component constant. The relationship is stored in advance. Specifically, when a peak appears at that position, the peak position for determining that the sample contains the gas component to be analyzed is determined for the target gas component, and then the gas component is determined. The relationship between the temperature of the column and the flow rate of the carrier gas at which the output peak always appears at that position is obtained in advance by experiments. Then, the relationship between the temperature and the flow rate is stored in the database of the storage unit 9 in the form of a table indicating the correspondence between the two and a relational expression (a function such as a linear expression) between the two.

  Then, the flow control unit 3 adjusts the flow rate of the carrier gas introduced by the pump 2 according to the temperature measured by the temperature sensor 6 based on the relationship between the temperature and the flow rate in the database of the storage unit 9. The peak of the output corresponding to the gas component to be analyzed appears at a predetermined peak position. As a result, an output peak indicating the presence of the gas component to be analyzed appears at a fixed position regardless of the temperature change of the column 5, and the output of the gas component to be analyzed can be detected with high accuracy.

  The adjustment of the peak position performed by the flow control unit 3 will be specifically described. First, as shown in FIG. 2A, it is assumed that a peak of a gas component to be analyzed appears at a time t1 at a certain temperature T1 and a flow rate f1 of a carrier gas. Here, it is assumed that the flow control unit 3 performs control such that the peak of the gas component to be analyzed always appears at this time t1. Then, assuming that only the temperature changes to T2 while the flow rate remains constant at f1, the peak position of the gas component to be analyzed is changed to the time t2, for example, as shown in FIG. Will change to In response to this temperature change, the flow control unit 3 obtains a flow rate f2 corresponding to the temperature T2 from the relationship between the temperature and the flow rate in the database of the storage unit 9 and changes the flow rate to f2, as shown in FIG. As shown in (1), the peak of the gas component to be analyzed appears at time t1.

  By performing such control, the peak of the gas component to be analyzed always appears at time t1, regardless of the temperature change of the column 5. Thereby, the determination unit 8 determines that the sample contains the gas to be analyzed by detecting that the peak appears at the time t1.

  As described above, the analyzer 1 according to the present embodiment can accurately detect the output of the gas component to be analyzed without using a heater. Further, since there is no need to use a heater, the size of the apparatus can be reduced by the amount of the heater, and further, the power consumed by the heater can be reduced, and energy can be saved.

[Other embodiments]
Finally, another embodiment of the gas analyzer according to the present invention will be described. Note that the configurations disclosed in the following embodiments can be applied in combination with configurations disclosed in other embodiments as long as no contradiction occurs.

(1) In the above embodiment, an example has been described in which a predetermined gas component is an analysis target, and an output peak corresponding to the analysis target gas component appears at a predetermined peak position. . However, embodiments of the present invention are not limited to this. For example, a plurality of gas components are analyzed, and among the plurality of gas components, the flow control unit 3 performs control such that an output peak corresponding to the selected gas component appears at a predetermined peak position. You may.

  In this case, for example, for each gas component, the relationship between the column temperature and the flow rate of the carrier gas at which the position of the appearing peak is constant is obtained in advance and stored in the database of the storage unit 9. A selection unit is provided for selecting a gas component to be subjected to flow control among a plurality of gas components, and the flow control unit 3 determines a column temperature and a carrier gas flow rate for the gas component selected by the selection unit. And the flow rate of the carrier gas is controlled in accordance with the temperature. Thus, when a gas to be analyzed is selected by the selection unit, the selected gas component always appears at a predetermined peak position, and it is determined whether or not the gas component is contained in the sample. Can be judged high. Further, by sequentially switching the gas components to be selected, it is possible to sequentially determine whether the sample contains the gas components to be analyzed. Note that the selection unit may be provided in the gas analyzer 1, or may be a unit that can be remotely operated by a remote controller or the like.

  In addition, it is also possible to automatically select which of the plurality of gas components is to be controlled based on the relationship between the column temperature and the flow rate of the carrier gas. In this case, for example, when a peak at a position close to any of the predetermined peak positions for each gas component appears in the output from the sensor 7, the flow control unit 3 sets the peak of the output from the sensor 7 to The flow rate of the carrier gas is adjusted according to the temperature measured by the temperature sensor 6 based on the relationship between the temperature of the column and the flow rate of the carrier gas for the gas component corresponding to the close peak position. If the peak of the output from the sensor 7 corresponds to the gas component to be controlled, the position of the peak of the output from the sensor 7 is controlled by the flow rate control unit 3 for the gas component to be controlled. It moves to a predetermined peak position. Thus, it can be determined that the sample contains the gas component to be controlled. If the peak of the output from the sensor 7 does not correspond to the gas component to be controlled, the position of the peak of the output from the sensor 7 moves to the predetermined peak position for the gas component to be controlled. And it is determined that the sample does not contain the gas component to be controlled.

(2) In the above embodiment, the configuration for determining whether or not the sample contains a gas to be analyzed has been described as an example. However, embodiments of the present invention are not limited to this. For example, the configuration may be such that the concentration of the gas component to be analyzed is further analyzed from the height and area of the peak.

(3) In the above embodiment, as a configuration for controlling the flow rate, the voltage applied to the pump 2 is changed based on the pressure-voltage table stored in the database of the storage unit 9 to the pressure corresponding to the target carrier gas flow rate. Is described as an example in which the flow rate of the carrier gas is adjusted by adjusting the voltage to be measured by the differential pressure sensor. However, embodiments of the present invention are not limited to this. For example, the flow rate may be controlled while directly measuring the flow rate using a flow rate sensor instead of the differential pressure sensor.

(4) In the above embodiment, the configuration in which the carrier gas is introduced into the introduction unit 4 by the suction pump 2 has been described as an example. However, embodiments of the present invention are not limited to this. For example, as shown in FIG. 3, the carrier gas may be introduced into the introduction unit 4 by a pump 2 of a pressure feed type.

(5) Regarding other configurations, it should be understood that the embodiments disclosed in the present specification are exemplifications in all respects, and that the scope of the present invention is not limited thereby. Those skilled in the art will readily understand that modifications can be made as appropriate without departing from the spirit of the present invention. Therefore, other embodiments modified without departing from the spirit of the present invention are naturally included in the scope of the present invention.

  INDUSTRIAL APPLICATION This invention can be utilized for the gas analyzer which analyzes the gas component in a sample, and its adjustment method, for example.

1 gas analyzer 2 pump 3 flow control unit (flow control unit)
5 Column 6 Temperature sensor 9 Storage unit

Claims (3)

A gas analyzer without a heater for separating a sample carried by a carrier gas by a column, detecting an output of at least one separated gas component, and controlling a temperature of the column ,
A storage unit that stores in advance the relationship between the temperature of the column and the flow rate of the carrier gas for keeping the output peak position in the target gas component constant,
A temperature sensor for measuring the temperature of the column,
And a flow controller configured to adjust a flow rate of the carrier gas according to a temperature measured by the temperature sensor based on the stored relationship. By adjusting the applied voltage, a pump capable of adjusting the flow rate of the introduced carrier gas,
A differential pressure sensor for measuring the pressure of the carrier gas to be introduced,
The flow rate control unit is configured to set the voltage applied to the pump to a target flow rate of the carrier gas based on a table indicating a correspondence relationship between the pressure measured by the differential pressure sensor and the voltage applied to the pump. A configuration in which the flow rate of the carrier gas is adjusted by adjusting the corresponding pressure to a voltage to be measured by the differential pressure sensor,
When the pressure measured by the differential pressure sensor at the time of startup and the voltage applied to the pump are different from the correspondence shown in the table, the table is corrected based on the relationship between the pressure and the voltage at startup. The gas analyzer according to claim 1, wherein the gas analyzer is configured. A method for adjusting a gas analyzer that does not include a heater that controls a temperature of a column by separating a sample carried by a carrier gas by a column and detecting an output of at least one separated gas component,
Determine the relationship between the temperature of the column and the flow rate of the carrier gas to make the peak position of the output in the gas component of interest constant,
Measuring the temperature of the column,
A method for adjusting a gas analyzer that adjusts a flow rate of the carrier gas according to a temperature of the column measured by a temperature sensor based on the obtained relationship.

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