SU1408280A1 - Apparatus for obtaining concentration of vapours of volatile substances - Google Patents

Abstract

This invention relates to gas analysis and can be used to create artificial vapor-gas mixtures in environmental analysis and to study absorption and adsorption. The purpose of the invention is to improve the accuracy of the analysis by obtaining a constant composition of vapors of substances with a wide range of volatility. The device contains a capillary p 7 of a lyophilic material, into the expanded part 8 of which another calibrated capillary p 4 is inserted with a gap, connected to a vessel 1 filled with a reference liquid. When air is passed through the system, its pressure in the gap 10 drops and the reference liquid is sucked into the Cagishla 7 at a speed proportional to the speed of the air flow, which ensures the constancy of the composition of the vapor-air mixture prepared. 1 il. i (L

Description

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 The invention relates to gas analysis and can be used to create artificial vapor-gas mixtures in the analysis of the environment and the study of adsorption and absorption.

The purpose of the invention is to increase the accuracy of the analysis by obtaining a time-constant composition of vapor of substances with a wide range of volatility.

The drawing shows a device for obtaining vapor concentrations of volatile substances, a general view,

The device contains a container 1 filled with a standard substance or its solution in a non-volatile liquid and having a stopper 2 with a valve 3, a calibrated capillary 4, connected to the container with a flexible tube 5, for example, silicone, placed in a thermostatic housing 6 capillary 7 from a conical material 8 at the end and connected to a breathing device 9 connected to an aspirator (not shown). The capillary p i is mounted coaxially with the capillary 7 with the possibility of horizontal displacement until its output loudness touches the inner surface of the conical nozzle 8 with the formation of an adjustable gap 10.

The device works as follows.

; The container 1 is filled with a reference liquid, such as benzene, or a solution of a volatile substance, such as camphor, a nonvolatile liquid, which is contaminated by the weight method.

Using a medical syringe (not Pictured), a calibrated capillary tube 4 injected a small volume of air through a silicone tube IB so that an air gap is formed at the beginning of capillary tube 4. Then through the system using an aspirator purge the air flow. At the same time, at the point of attachment of the capillary 4 with the capillary 7 in the gap 10, the air passes at high speed and its pressure is considerable (it drops. The standard liquid from the calibrated capillary 4 is sucked in | into the capillary p 7, spreads along its | Walls and diffuses into the air stream; ha. If the reference substance is dissolved in a non-volatile liquid, it diffuses into a stream of air from a thin film of non-volatile liquid;

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7. The higher the air flow rate, the greater the pressure in the gap 10 and the greater the rate of suction of the metered liquid from the capillary 4 to the capillary p 7, which leads to a proportionally larger amount of the substance being metered into the air flow . Thus, the concentration of the reference substance in the air flow remains constant over time.

By adjusting the size of the gap 10 by moving the capillary 4, it is possible at a constant volume velocity of air to change its rate of passage through the gap 10, the air pressure in this place and the rate of suction of the metered liquid in the capillary 7, and thus, at a constant flow rate of air to the extent necessary, the concentration of the resulting vapor-air mixture.

The volume of the metered liquid entering the capillary 7 is measured by the movement of the air gap. After the cessation of air supply, its pressure in the gap 10 increases to normal and the suction of the metered liquid from the capillary 4 to the capillary p 7 stops. Then capillary p 7 through

the nozzle 8 is flushed with an exact volume of the appropriate solvent. The residuals of the reference substance are then washed out with a solvent and the resulting solution is analyzed, for example, on a gas chromatograph. The results of the analysis are compared with the results of the determination by the same method of the amount of the reference substance supplied to the capillary 4, and the amount of the reference substance diffused into the air stream is determined. Taking into account the air volume passed through the capillary, the concentration of the dosing substance in the air flow is calculated.

The proposed device allows to create in the air flow a constant concentration of substances, the volatility of which fluctuates over a wide range, and substances that are in a solid state of aggregation, and also allows you to accurately calculate the amount of the reference substance dispensed into the air stream.

314082804

Claims (1)

The invention is a capillary connected to a container. A device for obtaining an end — by means of a flexible tube, capillaries of volatile vapor is switched on — equipped with a conical nozzle, narrowing the capillary, absorbing along the air flow, and an aspirator that is differently installed is coaxial. the fact that, in order to increase the accuracy of the capillary, an additional analysis due to obtaining a constant capillary is installed with the possibility of the time composition of the vapor composition of the substance to be displaced horizontally - with a wide range of volatility, it is, pkosnoveni its trailing edge is provided with a capacity for reference Yid-conical inner surface of the bone and additional kalibrovannymnasadki.