SU609088A1 - Device for collecting fractions of gas preparation chromatograph - Google Patents

Description

  one

The invention relates to preparative gas chromatography, in particular to devices for collecting fractions of substances separated in a chromatographic column.

A device 1 is known for switching collections of fractions of a preparative gas chromatograph, having switching devices located after collections of fractions, preventing direct contact of these devices with the fractions separated in the chromatographic column.

However, due to the effects of diffusion and pressure pulsation in pipelines and fraction collectors, the purity of the collected fractions may deteriorate.

A device for collecting fractions of a preparative gas chromatograph 2 is known, comprising an inlet manifold, fraction collectors connected to an inlet manifold, switching devices installed at the outlet of fraction collectors, an output collector and purge lines connected to gas channels between the inlet collector and fraction collectors. However, it also does not provide sufficient purity of the selected fractions.

The aim of the invention is to increase the purity of the selected fractions.

This is achieved by the fact that discharge lines with pneumatic resistances installed in them and in the lines after fraction collectors are connected to the inputs of fraction collectors, and in the pipelines connecting the input collector with fraction collectors on both sides of

the connection points of the purge line are installed buffer tanks. In addition, in order to reduce the losses of the collected fractions, pneumatic resistances in the lines after fraction collectors are installed after switching

devices, and the output ends of the reset lines are connected between switching devices and pneumatic resistances.

FIG. 1 shows a diagram of one of the variants of the proposed device; in fig.

2 is another device variant.

The device has inlet 1 and outlet 2 collectors, switching devices, for example valves 3, closing or opening the corresponding line, installed after fraction collectors 4, purge lines 5 connected between the input collector and fraction collectors, discharge lines 6 with pneumatic resistances 7 installed on them. , pneumatic resistances 8, installed in the lines of fraction collectors after the point of connection of discharge lines, for example after switching devices, and b) fern vessels 9 and 10, installed in pipelines 11 between the inlets one collector and place

connect purge lines and discharge lines.

For example, capillaries with a diameter of 0.7 mm and a length of 100-150 mm are used as pneumatic resistances 7, and resistances of connecting pipelines are used as pneumatic resistances 8. The volume of buffer tanks 9 is selected based on the absence of gas leakage from the inlet manifold into the not included fraction collectors and depends on the volume of these collections, on the size and nature of pressure fluctuations in the system and the temperature in the traps, and on the difference in gas flow in the extraction bottom and discharge. The volume of buffer tanks 10 is selected due to the absence of gas overshoot from uncoupled collectors (packings into the inlet manifold and depends on the volume of these collectors, on the size and nature of pressure fluctuations in the system and the temperature in the traps, and on the gas flow rate of the discharge line.

With a trap volume of 200–400 cm and flow rates along the purge and discharge lines 50 and 25, respectively, the volume of buffer tanks is 2–5 cm. Buffer tanks 9 and 10 are made in the form of segments of the corresponding pipelines And and 12 of the same volume, which ensures minimum mixing the gas stream inside these tanks.

The device works in the following way.

When one of the switching devices is opened (3, for example, the first), the carrier gas with the fractions separated in the chromatographic column (not shown in the diagram) comes from the inlet manifold 1 to the outlet manifold 2 through the corresponding fraction collection 4.

In this case, part of the gas is discharged through each discharge line 6 in quantities determined by the ratio of the resistance values of the pneumatic resistances 8 and 7. The flow rate of the carrier gas through the purge lines 5 selects more flow through the discharge line, for example, twice. Thus, the purge gas carrier is purged in the directions indicated by arrows in the scheme, the possibility of diffusion of the collected fractions from the fraction collections into the collector and back is excluded. In the variant of the device proposed (see Fig. 2), pneumatic resistances 8 are installed after switching devices 3, and the output ends of discharge lines 6 are connected to pipelines 12 between these switching devices and onevmal resistances.

In this embodiment, a part of the gas discharged through each discharge line 6, except the discharge line of the included trap, is determined by the ratio of the pneumatic resistance value 8 to the sum of the pneumatic resistance values 7 and 8,

and the part of the gas discharged through the reset line of the included trap is determined by the ratio of the magnitude of the pneumatic resistance of the line between the points of connection of the relief line to the magnitude of pneumatic resistance 7.

The use of the second variant of the scheme (see Fig. 2) is preferable with the requirements of ensuring minimal losses of the collected fractions.

The use of a device that provides high purity of the collected fractions makes it possible to take full advantage of this advantage of switching devices of fraction collectors with switching devices installed after fraction collection as the absence of contact of the separated fractions with these switching devices. This made it possible to develop a preparative chromatograph with a fully glass path to fraction collections, inclusive, operating at temperatures up to 300 ° C and ensuring the purity of the collected fractions up to 99.99%.

Claims (2)

Invention Formula A device for collecting fractions of a preparative gas chromatograph containing an inlet manifold, fraction collectors connected to the inlet manifold, switching devices installed at the outlet of fraction collectors, an output collector and purge lines connected to the gas canal / laM between the inlet collector and fraction collections characterized by that, in order to increase the purity of the selected fractions, discharge lines are connected to the inputs of the fraction collectors with the pneumatic resistances installed in them and in the lines after the fraction collections and conduits connecting the inlet manifold to the fraction collector on both sides of the seats connecting the purge line buffer tanks installed. 2. A device according to claim 1, characterized in that, in order to reduce losses of the collected fractions, pneumatic resistances in the lines after fractions collections are installed after the switching devices, and the output ends of the reset lines are connected between switching devices and pneumatic resistances. Sources of information taken into account in the examination 1. US patent, cl. 55-197, No. 3408793, 1968. 2. Sakodinsky K. I. and Volkov S. A. Preparative gas chromatography. M., “Himi, p. 155-192. ID- in t a: id / H about ij