SU890236A1 - Gas chromatograph - Google Patents

Description

This invention relates to gas chromatography used in the chemical, coal and other industries to determine the concentration of components in a gas mixture. A known chromatograph includes a gas circuit with a separation column, a detector and a recording device — an automatic potentiometer. The quantitative content of the component in the blend mixture is determined by the area of the corresponding peak of the chromatogram recorded by the GO potentiometer. The disadvantage of this chromatograph is the design complexity, and the fact that with sharp peaks the area measurement can lead to significant errors due to insufficient accuracy of the peak width measurement. In addition, fluctuations in the velocity of the carrier gas, the speed of movement of the chart recorder, and the shape of the output curve affect the accuracy of the area measurement. The speed of analysis on this chromatograph is low due to the processing time of the chromatograms. Electric measuring devices with inertial mass on the moving part (for example, a ballistic galvanometer) are known for measuring the amount of electricity 2. However, using them in their current form to integrate the chromatographic peak is difficult because of the significant error due to the inertial mass, Kotor increases the weight of the moving part and deterioration of instrument performance, in particular measurement accuracy. For example, for devices with a movable part on the cores, an increase in the weight of the movable part increases the friction in the supports, which causes a decrease in the accuracy of the readings. In devices on suspensions and extensions, an increase in the weight of the movable part also adversely affects the accuracy of the readings (impairs linearity, increases the variation of readings).

Closest to the present invention is a gas chromatograph containing a carrier gas supply channel, in which a metering unit, a chromatographic column and a detector are installed in series, the output of which is connected to an electric measuring instrument 3J.

The disadvantage of this chromatograph is a significant measurement error due to the fact that the meter reading is proportional to the height of the chromatographic peak, the value of which depends on such factors as carrier gas flow, pressure, etc.

To reduce the error, strict observance of the conditions of chromatography is required both when calibrating the chromatograph and when determining the content of the substance of interest in a sample of unknown composition by peak heights.

The purpose of the invention is to improve the measurement accuracy and efficiency of analysis,

The goal is achieved by the fact that in a gas chromatograph containing a carrier gas supply channel, in which a dosing unit is installed in series, a chromatographic column and a detector, the output of which is connected to an electrical measuring device, the latter is made in the form of a ballistic galvanometer under the inertial mass of the movable part the glass is installed, and the edges of the glass form a gap with the inertial mass, and the internal volume of the glass is connected through a choke to the channel for supplying the carrier gas.

1 shows a diagram of a gas chromatograph; figure 2 - electrical device.

The chromatograph contains a carrier gas channel 1, a dispenser 2, chromatographic column 3, detector k, branch 5i choke 6, and an electrical measuring device 7 consisting of a movable 8 (frame) and a fixed 3 case) part. The inertial mass in the form of a disk 10 is fixed on the moving part. 8. On the case of the electrical measuring device under the disk 10 with a minimum gap, the value of which

is adjusted by a screw 11, a metal cup 12 is installed, connected to the carrier gas line by means of a tube 13. The movable part 8 of the electrical measuring device is mounted on the tips 1.

The chromatograph works as follows.

The carrier gas is transported through the gas path introduced by the dispenser 2 analyzed gas sample, which is then separated on the chromatographic column 3 and detected by the detector 4. The signal from the detector is recorded by the electrical measuring device 7.

The presence of inertial mass at the movable part 8 of the electric measuring device increases the period of natural oscillations of the movable part, which makes it possible to make ballistic measurements, i.e. integrate the chromatographic peak area.

The carrier gas from chamber 1 through the throttle 6 and the tube 13 passes into the cup 12, creating pressure in it, thereby raising the disk 10 and unloading the lower stopper 14. This reduces the friction of the pair of core-boost and 8 generally increases the quality factor of the electrical measuring device and therefore measurement accuracy.

Frame 8 of the electrical measuring device, having received an impetus from the passage of a short current pulse when the sharp peak of the component emerges, makes a deviation - ballistic junk, which is a measure of the amount of electricity passed through the black frame of the instrument during the passage of current, and is proportional to the area of the chromatographic peak.

The use of an electrical measuring instrument with an inertial mass in the form of a disk mounted on its movable part, and a glass connected to a carrier gas line on a fixed gas chromatograph and an unmovable gas chromatograph, provides an increase in measurement accuracy and analysis efficiency.

Claims (3)

1. The US patent number 3070989, CL 72-23. 8 1963.. 2.Shkurin G.P. Electrical and radio metering devices N.,. .., with. 151. 3.V Khirev D.A., Shushunova A.F. Guide to gas chromatography, M ,, Higher School, 1975i S.Y. (prototype). / C / -0 LA 77 : f 1