SU1149162A1 - Device for sampling and introducing samples to chromatograph - Google Patents

Abstract

A DEVICE FOR THE SELECTION AND INPUT OF TESTS IN A CHROMATOGRAPH containing a carrier gas line, a metering valve connected to the chromatographic column inlet, a test gas line connected to the metering valve, a three-membrane reference element installed in the carrier gas line, and a junction lever mounted on it. A valve with an actuator and an indicator device installed in the carrier gas line, characterized in that, in order to simplify the design of the device, increase reliability in operation and reproducibility of the analysis, an additional On the carrier gas line, installed parallel to the main line, both carrier gas lines are connected to the flow chambers of the three-membrane reference element, the outlets of which are connected to the inlets of the metering valve, and the working chambers are three-membrane (the first comparison element is connected to the pneumatic control valve actuator Io valve.

Description

The invention relates to instrument making and can be used for taking and entering samples into a chromatograph. A device for sampling and insertion of samples, made in the form of a crane, equipped with a surge tank of piston type lj, is known. The disadvantage of this device is a sharp perturbation of the gas flow occurring at the time of introduction of the sample into the chromatographic column. The closest in technical essence and the achieved result to the invention is a device for sampling and insertion of samples into a chromatograph containing a carrier gas line, a crane doser connected to the inlet of the chromatographic column, an analyte gas line connected to the tap with a metering unit, a three-membrane comparison element installed in the carrier gas line, and a pneumatic control shut-off valve with an actuator and indicator device installed in the carrier gas line 2j. A disadvantage of the known device is that the equalization of pressure in the dosing volume with the pressure in the chromatographic column Oscidest is using a surge tank with a piston at the expense of the analyzed gas. This complicates the design of the device and reduces the reliability of its operation, and also reduces the reproducibility of the analysis due to the errors of the comparison element. The purpose of the invention is to simplify the design of the device, increase the reliability of the operation and increase the reproducibility of the analysis. This goal is achieved by the fact that in a device for taking and entering samples into a chromatograph containing a carrier gas line, a metering valve connected to the chromatographic column inlet, a test gas line connected to the metering valve, a three comparison membrane element installed in line carrier gas, and pneumatic control valve with actuator and indicator device installed in the carrier gas line, an additional gas carrier line is installed parallel to the main line, with both carrier gas lines Connected to flow chambers of a three-membrane comparison element, the outlets of which are connected to the inputs of the metering valve, and the working chambers of the three-membrane comparison element are connected to a pneumatic control valve actuator. Due to the additional carrier gas line connected to the flow chamber of the three-membrane comparison element, pressure equalization in the metering volume of the metering valve with the pressure in the chromatographic column is provided from the carrier gas line, in which pressure and flow regulators are installed, i.e. with a constant amount of the analyzed gas in the dosed volume. This makes it possible to drastically simplify the design of the device by eliminating the surge tank with a piston and, accordingly, increase the reliability of the device. In addition, the reproducibility of the analysis is enhanced by increasing the reproducibility of the dosage. Figure 1 shows the schematic diagram of the proposed device for sampling and insertion of samples into the chromatograph, in Figures 2 and 3 two working positions of the switch of the dispenser tap in Fig „4 are the diagram of pressure dependencies Рд J Pg and in chambers A, B, C and G three-membrane element comparison.; Fig. 5 is a graph of the dependence of the pressure of the test gas in the metering valve on time. The device consists of a three-way switchgear 1 with a drive 2 and a dosing volume 3, forming a metering valve, line 4 of the analyzed gas connected to the inlet 3 of the switchgear 1, lines 5 and 6 of the carrier gas. Line 5, containing pressure regulator 7 connected in series, flow regulator 8 5, chamber A of the three-membrane comparison element 9, is connected to the Q input of the distributor 1, Line b, sequentially connected pressure regulator 7, shut-off valve 10, cut-off valve 11c the drive 12 and the indicator device 13, the camera B of the three-membrane comparison element 9, is connected to the input of the distribution device 1, the Drive 12 is connected to the cameras C and D of the three-membrane comparison element 9. The output of the switchgear 1 through the dispensing volume 3 is connected to the input Z of the switchgear 1. The output Q of the switchgear 1 is connected via a column 14 to the chromatograph detector 15. Output k. switchgear 1 is designed to discharge gas. A device for taking and introducing samples into the chromatograph works as follows. Position I of the switchgear 1, time (figure 1). The analyzed gas under pressure Pp via line 4, channel e-e of the switchgear 1 is continuously supplied to the dosing volume 3, from which the channel 1 of the switchgear 1 is reset. The carrier gas under pressure is fed to the inlet of the column 14 via line 5 and the channel a-d of the distribution device}. When filling the line 6 with a carrier gas to the zakripy entrance 8 of the distribution device 1 in the chamber B of the comparison element 9, the pressure reaches the value +, where iPpp is the error of the compensation of the comparison element 9. When the chambers A and B reach the element 9 of the comparison of pressures that differ from by the value of f l R., i.e. Rd g Pg, closed nozzle connecting chambers C and D of element 9 of comparison with the atmosphere. The pressure in chambers B and D of the comparison element 9 and the actuator 12 becomes equal to the control pressure of Pd Pi, and the shut-off valve 11 closes. Position II of the switchgear 1, time, (figure 2). Analyzed gas under pressure PC, through line 4 and channel (-e) of the distributor 1 is released and reset. At the entrance of the column 14 under pressure In through line 3 - and the channel of th. The distribution device 1 is supplied with ha. The carrier is pressurized Pd R. Line 6 is connected via channel b of the distribution device 1 with a dosing volume 3 connected to the closed inlet j, distribution device 1. From time C, the pressure of the analyzed gas (Pd ) in the dosing volume 3 begins to increase, and in the chamber B of the comparison element 9 to fall, at the time T, the pressure required to open the nozzle connecting the chamber C and D of the element 9 compared with the atmosphere. The pressure in the actuator 12 drops to atmospheric (Pd-g / 1 (), and the valve 11 is opened. At the moment of time, the pressure in the metering volume 3 and the chamber B of the reference element 9 is equalized. Due to the further supply of carrier gas to the line 6, pressure in chamber B of reference element 9 and metering volume 3 occurs. At time c, pressure is reached and shut-off valve 11 is closed. Position III of switchgear 1, time after 4 (Fig. 3). Analyzed gas under pressure P along the line 4 and j switchgear channel and line 1 is connected to discharge. Line 5 through channel a-e of the distributor 1 is connected to the dispensing volume 3. The pressure in the dosing volume 3 and line 5 is different; c by the value of uPfp. Through the channel of the dispenser 1 of the dosages volume 3 sub-V It is connected to the inlet of column 14. The analyzed gas is supplied for analysis. Line 6 is in the same state as at position I of the switchgear 1. For the next analysis, the cycle is repeated. The use of the proposed device allows for a high stability of the zero line when the sample is introduced, thus increasing the reproducibility of the analyzes and eliminating the dependence on subjective factors. Pressure measurement and adjustment of the device for different sampling conditions and chromatographic analysis are not required, full automation of sample introduction is provided. Irregular consumption of the analyzed gas line allows one to avoid congested samples, which increases the diamic characteristics of the device and the efficiency of the analysis.

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Claims (1)

DEVICE FOR TAKING AND INPUT OF CHROMATOGRAPH SAMPLES, containing a carrier gas line, a metering valve connected to the inlet of the chromatographic column, a sample gas line connected to a metering valve, a three-membered comparison element installed in the carrier gas line, and a pneumatic control an air valve with an actuator and an indicator device installed in the carrier gas line, characterized in that, in order to simplify the design of the device, increase the reliability and reproducibility of the analysis, an additional Line carrier gas, installed parallel to the main line, and both lines are connected to the carrier gas with the flow chamber trehmembrannogo reference element, whose outputs are connected to inputs of the tap-dose-* torus and the working chamber trehmembrannogo comparison element are connected to the pneumatically driven shut-off valve. Riga 1 SU <., 1149182> ί 1,149,162 2