gas chromatograph

Abstract

To provide a gas chromatograph including an oven capable of being used at different power source voltages and outputting high power.SOLUTION: A gas chromatograph 1 includes an oven 3 having a first heater element 31 and a second heater element 32. The heater elements 31 and 32 are connected in series when a power source 5 is a first voltage, and are connected in parallel when the power source 5 is a second voltage lower than the first voltage. A power control section 4 includes a first control element 41 that controls ON / OFF of power supply to the heater elements 31 and 32 connected in series or that controls ON / OFF of power supply to the first heater element 31 connected in parallel, and a second control element 42 that controls ON / OFF of power supply to the second heater element 32 connected in parallel. A control section 2 adjusts a duty ratio of power supply to the heater elements 31 and 32 connected in parallel by controlling the control elements 41 and 42 when the power source 5 is the second voltage.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD

[0001] The present invention relates to a gas chromatograph including an oven that accommodates a column. BACKGROUND ART

[0002] A gas chromatograph generally includes a sample vaporization chamber, a column, and a detector. In the sample vaporization chamber, a liquid sample is vaporized by heating. In the column, the gas vaporized in the sample vaporization chamber is separated into individual compounds. In the detector, the concentration of each compound separated in the column is detected as an electrical signal. The column is accommodated in an oven provided with a heater element, and is maintained at a temperature suitable for analysis conditions during analysis.

[0003] Gas chromatographs are used in many countries and regions. The power supply voltage is 100 V or 200 V in Japan, 115 V or 230 V in the United States, and 220 V to 240 V in Europe, among other values. Since the supplied voltage differs depending on the location where the gas chromatograph is connected, a heater element corresponding to the power supply voltage is required to configure an oven having a specific power.

[0004] In order to cope with such differences in power supply voltage, gas chromatographs including a column oven capable of outputting a common power even for different power supply voltages have been proposed. This column oven has two heater elements having the same resistance value, and the two heater elements are configured in either a series connection or a parallel connection. For example, when connected to a power supply voltage of 200 V, the heater elements are connected in series, and when connected to a power supply voltage of 100 V, the heater elements are connected in parallel. With this configuration, the column oven can output the same power regardless of whether it receives power supply from a 100 V or 200 V power supply voltage. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-211225 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] As mentioned above, by configuring the two heater elements to be connected in either series or parallel, users can utilize a gas chromatograph with an oven that has a common power supply regardless of whether the power supply voltage is 100V or 200V. However, when such a gas chromatograph is connected to a 100V power supply, twice the current will flow compared to the 200V case.

[0007] When the current value increases, a large current flows through the electrical equipment such as cables within the device, requiring special specifications for that equipment. Therefore, when configuring a column oven with a common power output as described above, the resistance value of the heater element cannot be made too small in order to prevent a large current from flowing in a 100V operating environment. As a result, although the output power can be standardized, it was difficult to configure the device to output a large power even in a 200V operating environment.

[0008] The objective of the present invention is to provide a gas chromatograph equipped with an oven capable of outputting high power while being usable with different power supply voltages. [Means for solving the problem]

[0009] A gas chromatograph according to one aspect of the present invention comprises an oven containing a column having a first heater element and a second heater element, a power control unit that controls the power supplied from a power source to the oven, and a control unit that controls the operation of the gas chromatograph, wherein the first heater element and the second heater element are connected in series when the power source is a first voltage, or connected in parallel when the power source is a second voltage which is less than the first voltage, and the power control unit includes a first control element that controls the ON / OFF of the power supply to the series-connected first heater element and the second heater element, or controls the ON / OFF of the power supply to the parallel-connected first heater element, and a second control element that controls the ON / OFF of the power supply to the parallel-connected second heater element, wherein when the power source is a second voltage, the control unit adjusts the duty cycle of the power supply to the parallel-connected first heater element and the second heater element by controlling the first control element and the second control element. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a gas chromatograph equipped with an oven capable of outputting high power while being usable with different power supply voltages. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram showing a gas chromatograph according to this embodiment. [Figure 2] This diagram shows an oven and power control unit in a first connection configuration that utilizes a 200V power supply. [Figure 3] This diagram shows an oven and power control unit in a second connection configuration that utilizes a 100V power supply. [Figure 4] This figure shows an example of a control method in a first connection configuration that utilizes a 200V power supply. [Figure 5] This figure shows an example of a control method in a second connection configuration that utilizes a 100V power supply. [Figure 6] This figure shows another example of a control method in a second connection configuration that utilizes a 100V power supply. [Figure 7] This figure shows a control method for achieving the target output of the oven in the second connection configuration. [Figure 8] This figure shows a modified example of an oven and power control unit in a first connection configuration that utilizes a 200V power supply. [Figure 9] This figure shows a modified example of an oven and power control unit in a second connection configuration that utilizes a 100V power supply. [Modes for carrying out the invention]

[0012] Next, a gas chromatograph 1 according to an embodiment of the present invention will be described with reference to the attached drawings.

[0013] (1) Overall configuration of gas chromatograph 1 Figure 1 is an overall view of the gas chromatograph 1 according to this embodiment. The gas chromatograph 1 comprises a control unit 2, an oven 3, and a power control unit 4. In Figure 1, other components such as the sample vaporization chamber, the column for separating the sample, and the detector that detects the concentration of each compound separated in the column as an electrical signal are omitted from the illustration.

[0014] The control unit 2 comprises a CPU (Central Processing Unit) 21 and a PLD (Programmable Logic Device) 22. The CPU 21 performs overall control, including analysis processing by the gas chromatograph 1. The PLD 22 is a hardware logic element that provides hardware-controlled limitations to the power control in the power control unit 4.

[0015] The oven 3 includes a first heater element 31 and a second heater element 32, which are resistive heating elements. As shown in the drawing, the first heater element 31 and the second heater element 32 are each substantially semicircular, and the heater elements 31 and 32 together form a substantially circular shape. Here, a case where the first heater element 31 and the second heater element 32 have the same resistance value will be described as an example. The oven 3 also includes a column (not shown). The oven 3 raises the temperature inside the oven 3 by Joule heat generated by the first heater element 31 and the second heater element 32, and maintains the temperature inside the oven 3 at a constant temperature, for example, approximately several tens of degrees to about 450 degrees. Thereby, the column is heated to a temperature suitable for analysis processing. The oven 3 also includes a temperature sensor 33. Temperature information detected by the temperature sensor 33 is notified to the CPU 21. The CPU 21 performs temperature control of the oven 3 based on the temperature information of the oven 3 acquired from the temperature sensor 33.

[0016] The power control unit 4 controls the supply of power from the power source 5, which is a commercial power source, to the oven 3. The power control unit 4 includes a first control element 41, a second control element 42, and terminals 43a to 43e. The first control element 41 and the second control element 42 are configured of, for example, a thyristor or a triac. The power control unit 4 is connected to the power source 5 via the terminals 43a and 43b. The power control unit 4 is connected to the oven 3 via the terminals 43c to 43e.

[0017] The first control element 41 and the second control element 42 are connected in parallel to the power source 5 via the terminal 43a. The first control element 41 is connected via the terminal 43e to a terminal 31a provided at one end of the first heater element 31. The terminal 43c is connected to a terminal 31b provided at the other end of the first heater element 31, and to a terminal 32a provided at one end of the second heater element 32. Further, the terminal 43d is connected to a terminal 32b provided at the other end of the second heater element 32. In this embodiment, the terminal 43c is an example of the first terminal according to the present invention, and the terminal 43d is an example of the second terminal according to the present invention.

[0018] The terminal 43d is connected to either the second control element 42 or the terminal 43b in accordance with the settings of the gas chromatograph 1. Specifically, the connection destination of the terminal 43d is set according to the voltage of the power supply 5. FIG. 1 shows a state where the terminal 43d is connected to the second control element 42. The terminal 43b is connected to either the terminal 43c or the terminal 43d in accordance with the settings of the gas chromatograph 1. Specifically, the connection destination of the terminal 43b is set according to the voltage of the power supply 5. FIG. 1 shows a state where the terminal 43b is connected to the terminal 43c. With this configuration, the power control unit 4 can be changed to two types of connection configurations according to the voltage of the power supply 5.

[0019] (2) Connection configuration of the power control unit 4 Next, two types of connection configurations of the power control unit 4 will be described. FIG. 2 shows a first connection configuration. The first connection configuration is a configuration in which the first heater element 31 and the second heater element 32 are connected in series in the oven 3. In the present embodiment, when the power supply 5 is 200V, the first connection configuration is used. FIG. 3 shows a second connection configuration. The second connection configuration is a configuration in which the first heater element 31 and the second heater element 32 are connected in parallel in the oven 3. In the present embodiment, when the power supply 5 is 100V, the second connection configuration is used. In this embodiment, 200V is an example of the first voltage according to the present invention, and 100V is an example of the second voltage according to the present invention.

[0020] (2-1) First connection configuration (power supply 200V: heater elements connected in series) As shown in FIG. 2, in the first connection configuration, the terminal 43d is connected to the terminal 43b. In the first connection configuration, since the terminal 43d is not connected to the second control element 42, the second control element 42 is not used. Further, in the first connection configuration, no connection is established between the terminal 43c and the power supply 5. Accordingly, the first heater element 31 and the second heater element 32 are connected in series between the terminals 43a and 43b. The power supplied from the power supply 5 to the first heater element 31 and the second heater element 32 is turned ON / OFF by the first control element 41.

[0021] The temperature of oven 3 is controlled by the CPU 21. The CPU 21 controls the first control element 41 based on the target temperature of oven 3 set in the analysis conditions, and controls the power supplied from the power supply 5. The CPU 21 monitors the temperature information detected by the temperature sensor 33 (not shown in Figure 2) and performs control toward the target temperature. Control commands from the CPU 21 to the first control element 41 are executed via the PLD 22. The PLD 22 restricts the control of the first control element 41 by hardware.

[0022] Figure 4 shows an example of a control method in a first connection configuration using a 200V power supply. The upper part of Figure 4 shows the AC waveform of the current supplied from the power supply 5, with the horizontal axis representing time and the vertical axis representing the current value. The lower part of Figure 4 shows the power supply timing to the first heater element 31 and the second heater element 32, and is drawn with the AC waveform and time axis aligned in the upper part. In this embodiment, the CPU 21 controls the first control element 41 in half-wave units of the AC waveform.

[0023] In Figure 4, the time periods blacked out in the AC waveform represent the time periods when the first control element 41 is turned ON and current is supplied to the oven 3. In the lower circle, the upper semicircle schematically represents the first heater element 31, and the lower semicircle schematically represents the second heater element 32. The time periods blacked out in the upper semicircle indicate the time periods when power is supplied to the first heater element 31, and the time periods blacked out in the lower semicircle indicate the time periods when power is supplied to the second heater element 32. In the first connection configuration, the first heater element 31 and the second heater element 32 are connected in series, so either power is supplied to both heater elements 31 and 32, or power is not supplied to either heater element 31 or 32.

[0024] In Figure 4, period T11 is the period during which oven 3 is heated at 100% power (full power). Therefore, during period T11, power is supplied to the first heater element 31 and the second heater element 32 at all times. In other words, the CPU 21 gives a control instruction to turn on the first control element 41 at all times during period T11. In Figure 4, period T12 is the period during which oven 3 is heated at 66% power. Therefore, during period T12, power is supplied to the first heater element 31 and the second heater element 32 at a rate of 2 out of 3 times per half-wave. In other words, the CPU 21 gives a control instruction to turn on the first control element 41 at a rate of 2 out of 3 times per half-wave during period T12. In Figure 4, period T13 is the period during which oven 3 is heated at 33% power. Therefore, during period T13, power is supplied to the first heater element 31 and the second heater element 32 at a rate of 1 out of 3 times per half-wave. In other words, during period T13, the CPU 21 issues control instructions so that the first control element 41 turns ON at a rate of once every three times in half-wave units.

[0025] Thus, in the first connection configuration, the CPU 21 controls the heating of the oven 3 at an arbitrary duty cycle by controlling the first control element 41. The CPU 21 determines the duty cycle for heating the oven 3 based on the target temperature given by the analysis conditions and the temperature information obtained from the temperature sensor 33.

[0026] (2-2) Second connection configuration (100V power supply: heater elements connected in parallel) As shown in Figure 3, in the second connection configuration, terminal 43d is connected to the second control element 42. In the second connection configuration, both the first control element 41 and the second control element 42 are used to control the output of the oven 3. Also in the second connection configuration, terminal 43b is connected to terminal 43c. As a result, terminals 31b and 32a are connected to the power supply 5 via terminal 43c. This connects the first heater element 31 and the second heater element 32 in parallel between terminals 43a and 43b. The power supplied from the power supply 5 to the first heater element 31 is turned ON / OFF by the first control element 41, and the power supplied from the power supply 5 to the second heater element 32 is turned ON / OFF by the second control element 42.

[0027] The CPU 21 controls the first control element 41 and the second control element 42 based on the target temperature of the oven 3 set in the analysis conditions, and controls the power supply from the power supply 5. The CPU 21 monitors the temperature information detected by the temperature sensor 33 (not shown in Figure 3) and performs control toward the target temperature. Control commands issued by the CPU 21 to the first control element 41 and the second control element 42 are executed via the PLD 22.

[0028] Figure 5 shows an example of a control method in a second connection configuration using a 100V power supply. The upper part of Figure 5, similar to the upper part of Figure 4, shows the AC waveform of the current supplied from the power supply 5, with the horizontal axis representing time and the vertical axis representing the current value. The lower part of Figure 5, similar to the lower part of Figure 4, shows the power supply timing to the first heater element 31 and the second heater element 32, and is drawn with the AC waveform and time axis aligned in the upper part. In this embodiment, the CPU 21 controls the first control element 41 and the second control element 42 in half-wave units of the AC waveform.

[0029] In Figure 5, the time periods blacked out in the AC waveform represent the time periods when the first control element 41 and / or the second control element 42 are turned ON and current is supplied to the oven 3. The AC waveform shown in Figure 5 has two maximum current values, I1 and I2. The maximum value I1 occurs when power is supplied to both the first heater element 31 and the second heater element 32. The maximum value I2 occurs when power is supplied to either the first heater element 31 or the second heater element 32. In the second connection configuration, the first heater element 31 and the second heater element 32 are connected in parallel, so there are cases where power is supplied to both heater elements 31 and 32, where power is supplied to either heater element 31 or 32, and where power is not supplied to either heater element 31 or 32. When power is supplied to both heater elements 31 and 32, the maximum current value is I1. When power is supplied to either heater element 31 or 32, the maximum current value is I2.

[0030] In Figure 5, period T21 is the period during which oven 3 is heated at 66% power. Therefore, during period T21, power is supplied to both the first heater element 31 and the second heater element 32 at a rate of once every three half-wave intervals. During period T21, power is supplied to either the first heater element 31 or the second heater element 32 at a rate of two out of three half-wave intervals. In other words, during period T21, the CPU 21 gives control instructions to turn on both the first control element 41 and the second control element 42 at a rate of once every three half-wave intervals. During period T21, the CPU 21 gives control instructions to turn on either the first control element 41 or the second control element 42 at a rate of two out of three half-wave intervals.

[0031] In Figure 5, period T22 is the period during which the oven 3 is heated at 50% power. Therefore, during period T22, power is supplied to either the first heater element 31 or the second heater element 32 for the entire period. In other words, the CPU 21 gives a control instruction to turn ON either the first control element 41 or the second control element 42 for the entire period T22.

[0032] In Figure 5, period T23 is the period during which oven 3 is heated at 33% power. Therefore, during period T23, power is not supplied to either the first heater element 31 or the second heater element 32 at a rate of one in three times per half-wave. During period T23, power is supplied to either the first heater element 31 or the second heater element 32 at a rate of two in three times per half-wave. In other words, during period T23, the CPU 21 issues control instructions to turn both the first control element 41 and the second control element 42 OFF at a rate of one in three times per half-wave. During period T23, the CPU 21 issues control instructions to turn either the first control element 41 or the second control element 42 ON at a rate of two in three times per half-wave.

[0033] (2-3) Control method for the oven toward the target output in the second connection configuration Figures 6 and 7 show an example of another control method for a second connection configuration corresponding to a 100V power supply. In Figure 6, as in Figure 4, the first heater element 31 and the second heater element 32 are controlled in half-wave units of the AC waveform. In Figure 6, period T31 is the period during which the oven 3 is heated at 60% power. Therefore, during period T31, power is supplied to both the first heater element 31 and the second heater element 32 at a rate of once every five half-wave units. During period T31, power is supplied to either the first heater element 31 or the second heater element 32 at a rate of four out of five half-wave units.

[0034] In Figure 6, period T32 is the period during which oven 3 is heated at 30% power. Therefore, during period T32, power is not supplied to either the first heater element 31 or the second heater element 32 at a rate of 2 out of 5 times per half-wave. During period T32, power is supplied to either the first heater element 31 or the second heater element 32 at a rate of 3 out of 5 times per half-wave.

[0035] Furthermore, in either period T31 or T32, when power is supplied to either the first heater element 31 or the second heater element 32, power is supplied to the first heater element 31 and the second heater element 32 alternately. This prevents uneven temperature distribution within the oven 3.

[0036] In this way, the CPU 21 controls the heating of the oven 3 at any duty cycle by individually controlling the first control element 41 and the second control element 42. The CPU 21 determines the duty cycle for heating the oven 3 based on the target temperature given in the analysis conditions and the temperature information obtained from the temperature sensor 33.

[0037] Figure 7 shows the control method for the oven 3 toward the target output in the second connection configuration shown in Figure 6. In the figure, the numbers 1 to 24 are consecutive numbers indicating time in half-wave units. The "Integrated" column shows the integrated value of the oven 3's target output. In period T31, the target output is 60%, so a value of 60 is added for each half-wave unit. In period T32, the target output is 30%, so a value of 30 is added for each half-wave unit. In the "Output" column, "Up" means power is supplied to the first heater element 31, "Down" means power is supplied to the second heater element 32, and "Both" means power is supplied to both heater elements 31 and 32. "None" means that power is not supplied to either heater element 31 or 32. The output when power is supplied to either heater element 31 or 32 is 50, and the output when power is supplied to both is 100. The "Remainder" column shows the difference from the target output.

[0038] At time 1, 60 is added as the target output, and 50 is subtracted because power is supplied to the first heater element 31, resulting in a remainder of 10. At time 2, the target output of 60 is added to the remainder of 10 from time 1, and 50 is subtracted because power is supplied to the second heater element 32, resulting in a remainder of 20. At time 5, 60 is added as the target output to the remainder of 40 from time 4, and 100 is subtracted because power is supplied to both the first heater element 31 and the second heater element 32, resulting in a remainder of 0. In other words, if the cumulative value does not exceed 50, power is not supplied to either heater element 31 or 32. If the cumulative value exceeds 50 but does not exceed 100, power is supplied to either heater element 31 or 32. If the cumulative value exceeds 100, power is supplied to both heater elements 31 and 32.

[0039] Similarly, in period T32, at time 13, the target output of 30 is added to the "remainder" of time 12, which is 20. Power is supplied to the first heater element 31, so 50 is subtracted, and the "remainder" becomes 0. At time 14, the target output of 30 is added to the "remainder" of time 13, which is 0. However, the "integral" is 30, which is less than 50, so power is not supplied to either the first heater element 31 or the second heater element 32, and the "remainder" becomes 30.

[0040] (3) Effects of the embodiment As described above, the gas chromatograph 1 of this embodiment can be used by setting the oven 3 to either a first connection configuration or a second connection configuration depending on the voltage of the power supply 5. For example, when the power supply 5 is 200V, the oven 3 can be used as a high-output device by setting the gas chromatograph 1 to the first connection configuration. In other words, in the first connection configuration, the first heater element 31 and the second heater element 32 can be made with sufficiently low resistance values ​​so that the oven 3 can output high power.

[0041] When the resistance values ​​of the first heater element 31 and the second heater element 32 decrease, a large current will flow due to the circuit configuration, for example, when the power supply 5 is 100V and the device is used in the second connection configuration. When a large current flows through the power control unit 4, there is a problem that special specifications are required for electrical equipment such as cables. However, in the second connection configuration, the gas chromatograph 1 of this embodiment can reduce the duty cycle of the power supplied to the first heater element 31 and the second heater element 32 to less than 100 by controlling the ON / OFF of the first control element 41 and the second control element 42. By adjusting the duty cycle of the supplied power, it is possible to suppress the current value from becoming high even in the second connection configuration. This makes it possible to provide a universal power supply compatible gas chromatograph 1 that can be connected to power supplies 5 of different voltages, such as 100V and 200V. In a high-voltage environment such as 200V, the oven 3 functions as a high-output device, and in a standard voltage environment such as 100V, the oven 3 functions as a standard-output device.

[0042] Conventionally, attempts have been made to enable ovens to output the same power regardless of whether the power supply is 100V or 200V by allowing the use of two heater elements in two connection configurations: series connection and parallel connection. For example, suppose there are two power supply voltages, V and 2V, and the resistance of both heater elements is R. Then, when the power supply voltage is 2V, the heater elements are connected in series, and when the power supply voltage is V, the heater elements are connected in parallel. In this case, the power is 2V^2 / R in both the series and parallel connections. However, while the current in the series connection is V / R, the current in the parallel connection is twice that, 2V / R. Therefore, in order to prevent the current from becoming too large when using 100V, the value of R cannot be made too small, resulting in the problem that the power required when using 200V cannot be obtained. However, the power of a gas chromatograph oven is one of the indicators of oven performance, and users have a need to use the oven at high output when using a 200V power supply. Therefore, in the gas chromatograph 1 of this embodiment, the power when using 100V is reduced by adjusting the duty cycle of the power supply. This made it possible to reduce the resistance value of the heater element and enable high output of the oven 3 when using 200V, while preventing the current value when using 100V from becoming too large.

[0043] The power supply control to the first heater element 31 and the second heater element 32 toward the target output described above is achieved by the ON / OFF control of the first control element 41 and the second control element 42 by the CPU 21. Furthermore, in this embodiment, the control commands of the CPU 21 are given to the first control element 41 and the second control element 42 via the PLD 22. This allows the ON / OFF control of the first control element 41 and the second control element 42 to be restricted by hardware.

[0044] For example, by restricting the PLD22 to only turn on either the first control element 41 or the second control element 42, the output of the oven 3 can be limited to not exceeding 50%. In the example of the second connection configuration described in Figure 5 above, after both heater elements 31 and 32 are turned on by the PLD22, both heater elements 31 and 32 are restricted to not being turned on simultaneously at least twice in half-wave units. This allows the maximum power to be limited to 66% when using a 100V power supply. Also, in the example in Figure 5, a large current flows instantaneously when the power is controlled at 66%. However, by limiting the duty cycle to 50% with the PLD22, the maximum instantaneous current can also be suppressed. In other words, the PLD22 can limit the duty cycle of power supply to the first control element 41 and the second control element 42 to a predetermined value. Even if the CPU 21 issues an incorrect instruction for some reason, it is possible to limit the output of the oven 3 through hardware control.

[0045] (4) Variations Next, a modified version of the gas chromatograph 1 of this embodiment will be described. Figures 8 and 9 show the oven 3A and power control unit 4 included in the modified gas chromatograph 1. The configuration of the power control unit 4 is the same as in the embodiment described above. The first heater element 31A and the second heater element 32A of the oven 3A are substantially circular in shape. The first heater element 31A and the second heater element 32A are arranged so that their centers align, and the heater element as a whole has a double-circle configuration. This configuration makes it possible to suppress the occurrence of temperature unevenness in the oven 3. In the embodiment described above, the occurrence of temperature unevenness is suppressed by supplying power alternately to the first heater element 31 and the second heater element 32, but in this modified version, the temperature inside the oven 3 can be maintained uniformly without such control.

[0046] In the above embodiment, the case where the resistance values ​​of the first heater element 31 and the second heater element 32 are the same was described as an example, but this is just one example. The resistance values ​​of the first heater element 31 and the second heater element 32 may be different. In the above embodiment, the case where the gas chromatograph 1 is used in the first connection configuration when the power supply voltage is 200V and the gas chromatograph 1 is used in the second connection configuration when the power supply voltage is 100V was described as an example, but this is just one example. There is an advantage to using the second connection configuration when the voltage of the power supply connected in the second connection configuration is lower than the voltage of the power supply connected in the first connection configuration. For example, the first connection configuration may be used when the power supply voltage is 230V and the second connection configuration may be used when it is 115V.

[0047] In the above embodiment, a gas chromatograph 1 comprising the control unit 2, oven 3, and power control unit 4 of this embodiment was described as an example, but this embodiment is also applicable to a gas chromatograph-mass spectrometer.

[0048] (5) Aspect Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following embodiments.

[0049] (Section 1) A gas chromatograph according to one embodiment is: An oven having a first heater element and a second heater element, in which a column is housed, A power control unit that controls the power supplied from the power source to the oven, A control unit that controls the operation of the gas chromatograph, Equipped with, The first heater element and the second heater element are connected in series when the power supply is at a first voltage, or in parallel when the power supply is at a second voltage lower than the first voltage. The power control unit, A first control element that controls the ON / OFF of the power supply to the first heater element and the second heater element connected in series, or controls the ON / OFF of the power supply to the first heater element connected in parallel, A second control element that controls the ON / OFF of the power supply to the second heater element connected in parallel, Includes, The control unit, When the power supply is at the second voltage, the duty cycle of power supply to the parallel-connected first heater element and second heater element is adjusted by controlling the first control element and the second control element.

[0050] The current value when using the second voltage can be reduced. This makes it possible to reduce the resistance value of the heater element, allowing the oven to be configured for high output when using the first voltage. This makes it possible to provide a gas chromatograph equipped with an oven that can output high power while being usable with different power supply voltages.

[0051] (Section 2) In the gas chromatograph described in paragraph 1, The control unit, When the power supply is at the first voltage, the duty cycle of power supply to the series-connected first heater element and second heater element may be adjusted by controlling the first control element.

[0052] The oven output can be adjusted when using the first voltage.

[0053] (Section 3) In the gas chromatograph described in paragraph 1, The resistance values ​​of the first heater element and the second heater element are the same, and the first voltage may be twice the second voltage.

[0054] We can provide gas chromatographs compatible with universal power supplies.

[0055] (Section 4) In the gas chromatograph described in paragraph 1, The control unit may control the ON / OFF switching of power supply to the first heater element and the second heater element in half-wave units of the current supplied from the power supply.

[0056] The oven's output can be adjusted to the desired duty cycle.

[0057] (Section 5) In the gas chromatograph described in paragraph 1, The control unit may alternately turn ON the power supply to the first heater element and the second heater element.

[0058] This helps to suppress uneven temperature distribution inside the oven.

[0059] (Section 6) In the gas chromatograph described in paragraph 1, The control unit, The system may include a hardware logic element that limits the duty cycle of power supply to the first heater element and the second heater element to a predetermined value.

[0060] By limiting the oven's duty cycle through hardware, it is possible to limit the oven's power output.

[0061] (Section 7) In the gas chromatograph described in paragraph 1, One end of the first control element and one end of the second control element are connected in parallel to one end of the power supply, one end of the first heater element is connected to the other end of the first control element, the other end of the first heater element is connected to one end of the second heater element and the first terminal, the other end of the second heater element is connected to the second terminal, and the power supply may be switched so that when it is at the first voltage, the second terminal is connected to the other end of the power supply, and when it is at the second voltage, the first terminal is connected to the other end of the power supply and the second terminal is connected to the other end of the second control element.

[0062] By changing the connections between terminals, it is possible to accommodate both the first and second voltages.

[0063] (Section 8) In the gas chromatograph described in paragraph 1, The first heater element and the second heater element may have a substantially semicircular shape, and may be connected to form a substantially circular heater element.

[0064] By combining the first and second heater elements, they are used as a circular heater element to heat the inside of an oven.

[0065] (Section 9) In the gas chromatograph described in paragraph 1, The first heater element and the second heater element may have a substantially circular shape, and may be connected to form a double circular heater element.

[0066] Even when power is supplied to either the first or second heater element, temperature unevenness inside the oven can be suppressed. [Explanation of Symbols]

[0067] 1...Gas chromatograph, 2...Control unit, 21...CPU, 22...PLD, 3...Oven, 31...First heater element, 32...Second heater element, 33...Temperature sensor, 4...Power control unit, 41...First control element, 42...Second control element, 5...Power supply

Claims

1. An oven having a first heater element and a second heater element, in which a column is housed, A power control unit that controls the power supplied from the power source to the oven, A chromatograph control unit that controls the operation of the gas chromatograph, Equipped with, The first heater element and the second heater element are connected in series when the power supply is at a first voltage, or in parallel when the power supply is at a second voltage lower than the first voltage. The power control unit, A first control element that controls the ON / OFF of power supply to the first heater element and the second heater element connected in series, or controls the ON / OFF of power supply to the first heater element connected in parallel, A second control element that controls the ON / OFF of the power supply to the second heater element connected in parallel, Includes, The chromatograph control unit is, A gas chromatograph that, when the power supply is the second voltage, controls the first control element and the second control element to adjust the duty cycle of power supply to the first heater element and the second heater element, which are connected in parallel, so that the peak current flowing through the power control unit is suppressed to a predetermined value or less.

2. The chromatograph control unit is, The gas chromatograph according to claim 1, wherein when the power supply is at the first voltage, the duty cycle of power supply to the first heater element and the second heater element connected in series is adjusted by controlling the first control element.

3. The gas chromatograph according to claim 1, wherein the resistance values ​​of the first heater element and the second heater element are the same, and the first voltage is twice the second voltage.

4. The gas chromatograph according to claim 1, wherein the chromatograph control unit controls the ON / OFF switching of power supply to the first heater element and the second heater element in half-wave units of the current supplied from the power supply.

5. The gas chromatograph according to claim 1, wherein the chromatograph control unit alternately turns ON the power supply to the first heater element and the second heater element.

6. The chromatograph control unit is, The gas chromatograph according to claim 1, further comprising a hardware logic element that limits the duty cycle of power supply to the first heater element and the second heater element to a predetermined value.

7. An oven having a first heater element and a second heater element, in which a column is housed, A power control unit that controls the power supplied from the power source to the oven, A chromatograph control unit that controls the operation of the gas chromatograph, Equipped with, The first heater element and the second heater element are connected in series when the power supply is at a first voltage, or in parallel when the power supply is at a second voltage lower than the first voltage. The power control unit, A first control element that controls the ON / OFF of power supply to the first heater element and the second heater element connected in series, or controls the ON / OFF of power supply to the first heater element connected in parallel, A second control element that controls the ON / OFF of the power supply to the second heater element connected in parallel, Includes, The chromatograph control unit is, When the power supply is at the second voltage, the duty cycle of power supply to the parallel-connected first heater element and second heater element is adjusted by controlling the first control element and the second control element. A gas chromatograph in which one end of the first control element and one end of the second control element are connected in parallel to one end of the power supply, one end of the first heater element is connected to the other end of the first control element, the other end of the first heater element is connected to one end of the second heater element and to the first terminal, the other end of the second heater element is connected to the second terminal, and when the power supply is at the first voltage, the second terminal is connected to the other end of the power supply, and when the power supply is at the second voltage, the first terminal is connected to the other end of the power supply and the second terminal is connected to the other end of the second control element, and the power supply is switched to do so.

8. An oven having a first heater element and a second heater element, in which a column is housed, A power control unit that controls the power supplied from the power source to the oven, A chromatograph control unit that controls the operation of the gas chromatograph, Equipped with, The first heater element and the second heater element are connected in series when the power supply is at a first voltage, or in parallel when the power supply is at a second voltage lower than the first voltage. The power control unit, A first control element that controls the ON / OFF of power supply to the first heater element and the second heater element connected in series, or controls the ON / OFF of power supply to the first heater element connected in parallel, A second control element that controls the ON / OFF of the power supply to the second heater element connected in parallel, Includes, The chromatograph control unit is, When the power supply is at the second voltage, the duty cycle of power supply to the parallel-connected first heater element and second heater element is adjusted by controlling the first control element and the second control element. A gas chromatograph in which the first heater element and the second heater element have a substantially semicircular shape, and when the first heater element and the second heater element are connected, they are configured as a substantially circular heater element.

9. An oven having a first heater element and a second heater element, in which a column is housed, A power control unit that controls the power supplied from the power source to the oven, A chromatograph control unit that controls the operation of the gas chromatograph, Equipped with, The first heater element and the second heater element are connected in series when the power supply is at a first voltage, or in parallel when the power supply is at a second voltage lower than the first voltage. The power control unit, A first control element that controls the ON / OFF of power supply to the first heater element and the second heater element connected in series, or controls the ON / OFF of power supply to the first heater element connected in parallel, A second control element that controls the ON / OFF of the power supply to the second heater element connected in parallel, Includes, The chromatograph control unit is, When the power supply is at the second voltage, the duty cycle of power supply to the parallel-connected first heater element and second heater element is adjusted by controlling the first control element and the second control element. A gas chromatograph in which the first heater element and the second heater element have a substantially circular shape, and the first heater element and the second heater element are connected to form a double circular heater element.

Images