SU1469451A1 - Apparatus for placing samples in gas chromatograph - Google Patents

Abstract

This invention relates to an analytical instrument making, namely gas chromatography. The aim of the invention is to eliminate the diffusion of vaporized vapor of the sample into gas communications. The device comprises a sample carrier and an evaporator comprising a housing, a cap nut, a membrane of self-sealing material, an evaporation chamber, a channel for adding carrier gas, and a sleeve with an axial opening for introducing the sample between the membrane and the evaporation chamber. A radial bore is made in the sleeve, connecting the channel for supplying the carrier gas with the axial bore. A valve is placed in the radial opening of the sleeve, which represents a saddle and a freely floating spherical locking element that interacts with the needle of the sample carrier when it is inserted. When the needle is inserted into the evaporator, a free-floating spherical closure element is pressed against the valve seat, eliminating the possibility of sample vapors entering the gas inlet channel. 1 il. WITH

Description

I

The invention relates to analytical instrumentation, namely gas chromatography,

 The aim of the invention is to prevent diffusion of sample vapors into gas communications.

The drawing shows the proposed device at the time of entry of the sample.

The device contains a sample carrier 1, made, for example, in the form of a microsyringe, and an evaporator 2 containing a cap nut 3. In the housing

4 evaporators located membrane

5 of the self-sealing material, glass liner 6, evaporation chamber 7, channel 8 dp of gas carrier supply, sleeve 9 in which axial channel 10 for inserting the needle t1 of sample carrier 1 and radial channel 12 connecting the channel 8 to axial channel . In the radial channel 12 of the sleeve 9, a valve 13 is installed, comprising a seat 14 and a spherical locking element 15, which in the open position of the valve 13 intersects the axial bore 10.

The device works as follows.

At the initial moment preceding sample introduction, the flow of carrier gas is continuously supplied through channel 8 through the opening in valve seat 14.

one

o :) o

4 SP

13, the gap between the freely floating spherical element 15 and the sleeve

9 in the axial canap 10, and then into the evaporation chamber 7 of the evaporator 2. In this case, the locking element 15, with a stream of carrier gas leaving the opening in the seat 1A, moves to a position in which the valve 13 is fully open and the locking element

15 overlaps the axial channel 10 for inserting the needle 11 into the evaporation chamber 7. A sample of the analyzed mixture is taken using a syringe 1. The needle 11 of the syringe 1 through the membrane 5 and the axial channel

10, the sleeve 9 is inserted into the evaporator 2. When the needle 11 is inserted, the locking element 15 is pushed out by the needle 11 from the axial channel 10 and pressed against the seat 14 of the stop valve 13. In this case, the movement of the carrier gas from the channel 8

into the vaporization chamber 7, it stops completely or is limited to the amount of gas leakage that may occur due to insufficient compaction force. As the gas flow regulator (not shown) delivers the required flow rate of the carrier gas, the pressure in channel 8 begins to increase rapidly. When the sample is injected and evaporated in the evaporation chamber 7, the pressure rises sharply to a value several times higher than the gas pressure entering the column (not shown). With this pressure surge, the closure element 15 is additionally pressed against the seat 14 and remains in this position until the pressure in the evaporation chamber 7 is greater than in channel 8, even if the needle 11 is removed from the evaporator 2. The high pressure in the evaporation chamber 7 provides intensive movement of sample vapors into the column from the evaporation chamber 7, in which the pressure drops as the sample vapors pass into the column. After the pressures in the vaporization chamber 7 and the gas supply channel 8 are equal, the valve 13 is opened. Rebuilds

ten

ts

20

25

t n- 469451

The gas carrier is carried out, the flow of which remnants of the evaporated sample from the evaporation chamber 7 are transferred to the column.

The tapered end of the sleeve 9 facing the glass liner 6 is rubbed during manufacture of the evaporator case 2 to the body 4. This ensures that the sleeve 9 is tightly sealed to the body 4 by applying to the sleeve 9 a constant sealing force created by the deformed membrane 5.

The locking element 15 and the saddle 14 should preferably be made of an adhesive-resistant material, such as ruby or sapphire. This will ensure that the valve is sealed at low sealing forces.

Claims (1)

The use of the proposed device will make it possible to eliminate the diffusion of vaporized vapor of the sample into gas communications and thereby increase the separation efficiency. Invention Formula A device for introducing samples into a gas chromatograph containing a sample carrier with a needle, an evaporator including Kopjtyc, an evaporation chamber, a channel for supplying carrier gas with a non-return valve with a floating spherical locking element installed, a membrane made of self-sealing material, a cap nut and a sleeve with an axial channel installed between the membrane and the evaporation chamber, characterized in that, in order to prevent diffusion of sample vapors into the gas communications, a check valve is installed in the radial channel of the sleeve connecting a channel for supplying a carrier gas with an axial channel for sample introduction, so that the floating spherical locking element cooperates with the needle carrier and the sample value freewheel floating spherical member equal to the thickness of the needle carrier sample. thirty 35 40