JPH0127387B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for providing a standard sample to a process gas chromatograph and calibrating its measurements.

Generally, a gas chromatograph is an analyzer that separates a multi-component sample into each component and performs quantitative analysis of each component. The entire system of the conventional apparatus is comprised of an analyzer 1, a processor 2, a programmer 3, and a recorder 4, as shown in FIG.

The analyzer 1 separates the collected sample into each component, and converts the concentration into an electrical signal using a detector. The processor 2 adjusts this electrical signal to a voltage within a certain range and transmits it to the recorder 4 and data calculation device 5' as a concentration signal of each component.

Since the gas chromatograph separates multiple components using differences in elution time, the programmer 3 temporally controls the entire system and sends signals to the analyzer 1 and processor 2 to instruct various operation times. All power supply voltage on/off signals are transmitted to the analyzer 1 to drive the electromagnetic valves, and contact on/off signals are transmitted to the processor 2. Introducing the sample to analyzer 1,
Sequence signals for column switching, flow path switching, etc., are sent to the processor 2 at predetermined times for selection of measurement components, baseline correction, flow path identification/return, etc.

In such a device, it is necessary to calibrate the measured values in order to make the electric signal obtained from the device output correspond to the component concentration of the sample given to the device.
Conventionally, this calibration involved preparing a standard gas whose component concentration was known in advance, supplying it as a sample to the device, and manually adjusting the measured value at that time to match the component concentration. It was done. The outline of this operation is as follows.

(1) Sampling the standard gas, equipping it with equipment, and performing analysis operations.

(2) Repeat the above operation until the indicated value becomes stable.

(3) Once the indicated value has stabilized, the attenuator is adjusted by calculating or calculating the correction amount from the difference between the indicated value and the standard gas concentration. This is done for all measured components.

(4) After adjusting the attenuator, repeat the operation in (1) above and confirm that the indicated value matches the standard gas concentration and is stable.

Such an operation requires half a day to a full day of man-hours even for an experienced worker, and since the device is subject to fluctuations due to sensitivity deterioration, etc., it is necessary to repeat this every time the device is used for a certain period of time.

The present invention is an improvement on this, and aims to provide a gas chromatograph that can automatically and quickly calibrate the measured values of the device.

The present invention includes an analyzer that collects a gas sample and obtains an electrical signal corresponding to the component concentration of the gas sample;
A processor that controls the operation of the analyzer and processes the output electrical signals of the analyzer, and a device that supplies a standard gas whose component concentration is known in advance as the gas sample through a solenoid valve controlled by the processor. In the method for calibrating a gas chromatograph, each time an operation of analyzing a measurement gas a preset number of times is executed, a device for supplying the standard gas to the analyzer is activated to analyze the standard gas. , records the analysis result of the standard gas using chromatography, and compares the measured component signal indicating the analysis result of the standard gas with the standard gas concentration signal stored in memory in advance to determine whether it falls within a certain reference value. The analysis of the standard gas and the comparison operation are performed a certain number of n _s times, and the number of n _s
When all of the analysis results are within a certain standard, it is determined that the reproducibility is good, and the processor corrects the data calculation constants for processing the output electrical signal based on the chromatography record. It is characterized by

Further, it is preferable that the calculation constant of the processor is controlled to be automatically corrected based on the result of comparison with the component concentration of the standard gas.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 3 is a block diagram of a gas chromatograph according to an embodiment of the present invention.

6 is a detector that detects the component concentration of the sample sent into the analyzer 1 and outputs the signal (0
~1mV, 0~10V) is sent to the first stage amplifier 7 of the processor 2. The signal sent to this amplifier 7 is amplified and filtered, and then amplified by a programmable gain amplifier 8 to an appropriate range for AD conversion. This gain is preset in the microprocessor 5 and commanded via the bus and latch circuit 10. In the case of chromatographic recording, the output signal of the amplifier 8 is outputted as is to the terminal 11 of the recorder 4 via the switch 9.

12 is an AD comparator. First, a standard gas concentration signal preset in the microprocessor 5 and stored in the memory 21 is input to one input terminal of the comparator 12 via the latch circuit 10 and the DA converter 13, and then the analog signal A It is supplied as _s . In addition, to the other input terminal of the AD comparator 12, a measured component concentration signal detected from the sample gas or standard gas and amplified by the amplifier 7 or the programmable gain amplifier 8 is inputted as the output analog signal A _n of the amplifier 8. Ru. For this reason, A.D.
The output A _n of the amplifier 8 and the output A _s of the DA converter 13 are compared by the comparator 12, and the comparison result is taken into the microprocessor 5 to determine whether or not they are within a certain reference value. be judged. This series of comparison operations is performed by the microprocessor 5,
This is performed sequentially by a loop of the DA converter 13 and the comparator 12.

14 is a baseline correction circuit. In order to accurately measure the component concentration, a voltage with the opposite sign to the input signal is applied to the output of the amplifier 7 immediately before the peak appears to perform rough correction. Thereafter, precise correction calculations are performed digitally within the microprocessor 5. Next, when the component peak signal of the input signal is taken into the microprocessor 5, peak area calculation, peak height detection, retention time measurement, etc. are performed, and the DA converter 13 is used in a time-sharing manner to demultiplex the signal. Output to Tsukusa 15. These signals are sent to the terminal 11 via the switch 16 in the case of bar graph recording for each measured component, and are sent to the terminal 17 in the case of trend recording, and input into the recorder 4. Note that 10 is a latch circuit. In addition, in the case of bar recording, the paper feed signal is
8 is output.

19 is a solenoid valve of the analyzer 1. One of the electromagnetic valves 19 is connected to a standard gas supply device whose component concentration is known in advance. In the sequence, according to a list written in advance in the memory 21, the sequence step advances every time the timer 22 times up, and is output to the analyzer 1 as an on/off signal for the solenoid valve 19.

Reference numeral 23 denotes a keyboard, and 24 a display, which are arranged in front of the operation panel, and are used to write parameters and read various data.

Reference numeral 25 is a printer for printing measurement data, abnormalities, etc. Reference numeral 26 is a cassette tape, which is provided for loading and saving various parameters.
This will input a signal if memory is lost.

The calibration operation of such a device will be explained.
The calibration operation is initiated by a calibration activation trigger. The activation trigger is automatically given every n times of process sample analysis (can be set arbitrarily);
It may be given by operating the operation panel.

When a starting trigger is given, the electromagnetic valve 19 shown in FIG. 3 corresponding to the standard gas is controlled to sample a specified amount of the standard gas. Continuing,
The signal appearing at the output of the amplifier 7 is analyzed according to the operation described above, and the result is compared with the component concentration of the standard gas previously stored in the memory 21. That is, the signal appearing at the output of the amplifier 7 is amplified and filtered, and then amplified by the programmable gain amplifier 8 to an appropriate range for AD conversion, and then sent to one input of the comparator 13 as the output analog signal A _n of the amplifier 8. input to the terminal. Further, the standard gas concentration signal stored in the memory 21 is connected to the other input terminal of the comparator 13 by the latch circuit 10 and the DA
It is supplied as an analog signal A _s via a converter 13 . Therefore, the output A _n of the amplifier 8 and the output of the DA converter 13 are determined by the AD comparator 12.
A _s is compared, and the comparison result is taken into the microprocessor 5 to determine whether or not it falls within a certain reference value. This series of operations is repeated several times, and if the comparison results obtained are within a certain standard, the analysis value is determined to be normal.

This analysis operation is repeated n _s times, and when the difference between the maximum and minimum analysis results exceeds a certain standard, the analysis operation is performed an additional n _s times. Furthermore, if a certain standard is exceeded, the above analysis operation is repeated up to a preset m times, and if the above certain standard is still exceeded, a warning is issued indicating poor reproducibility.

When no alarm occurs, the reproducibility is good;
Calculate the correction value so that the analytical value matches the standard gas concentration. The data calculation constants are automatically corrected using this correction value. Subsequently, the series of operations described above is automatically performed again, and the standard gas is analyzed. This result is compared with the composition of a standard gas,
It is confirmed that the comparison result is within a certain standard. At this time, when a certain standard is exceeded, a self-diagnosis alarm is issued and a warning is issued.

Although it is possible to configure the device to stop operation due to the various types of alarms mentioned above, in general, it is possible to return the device to the analysis process in the alarm state without stopping the device operation, and automatically continue with the next analysis. It is good to make it work.

As described above, according to the present invention, a gas chromatograph can be calibrated automatically and with high precision without human intervention. By implementing the present invention, the man-hours for calibration are significantly reduced, making it economical to maintain the equipment, and the frequency of calibration can be increased, ensuring that the measured values of the process gas chromatograph are always accurate. There are certain effects that can be achieved.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a conventional gas chromatograph. Figure 2 is an example of a gas chromatogram showing the sequence signal. FIG. 3 is a configuration diagram of a gas chromatograph according to an embodiment of the present invention. 1... Analyzer, 2... Processor, 3...
Programmer, 4...Recorder, 5...Microprocessor, 5'...Data calculation device, 6...Detector,
7... First stage amplifier, 8... Programmable gain amplifier, 9, 16... Switch, 11, 17, 1
8...Terminal, 10...Latch circuit, 12...AD
Comparator, 13...DA converter, 14...Baseline correction circuit, 15...Demultiplexer, 1
9...Solenoid valve, 21...Memory, 22...Timer, 23...Keyboard, 24...Display, 25...Printer, 26...Cassette tape.

Claims (1)

[Scope of Claims] 1. An analyzer that collects a gas sample and obtains an electrical signal corresponding to the component concentration of the gas sample; a processor that controls the operation of the analyzer and processes the output electrical signal of the analyzer; A method for calibrating a gas chromatograph, comprising a device for supplying a standard gas whose component concentration is known in advance as the gas sample through a solenoid valve controlled by a processor, in which a measurement gas is analyzed a preset number of times n times. Each time an operation is executed, a device for supplying the standard gas to the analyzer is activated, the standard gas is analyzed, and the analysis results of the standard gas are recorded by chromatography, and the analysis results of the standard gas are also shown. Compare the measured component signal with a standard gas concentration signal stored in a memory in advance to determine whether it is within a certain reference value, and perform the analysis of the standard gas and the comparison operation a certain number of _times. , when the results of the plurality of n _s analyzes are all within a certain standard, it is determined that the reproducibility is good, and the data calculation constant for processing the output electrical signal is corrected based on the chromatography record. A method for calibrating a gas chromatograph, characterized in that the entire process is performed by the processor.