RU2280246C1 - Capillary batcher for steam-gas mixtures - Google Patents

Abstract

FIELD: technology for analyzing materials by determining their chemical and physical properties, namely, for production or preparation of samples for research by means of their dilution, spraying or mixing.

SUBSTANCE: capillary batcher of steam-gas mixtures, consists of mixing chamber with feeding and draining connecting pipes, evaporator chambers with batched substance and capillary. Evaporating chamber with substance to be batched is made in form of cylinder-shaped glass vialla with replaceable nozzles and capillaries of different pass section for forming steam-gas mixtures with different volatility in broad range of concentrations and forms a detachable connection together with mixing chamber. Capillary diameter d is determined in accordance to formula

where: p - mass concentration of goal component in gas mixture, Q - gas flow of gas mixture diluter, p_Σ - mass concentration of steam-gas mixture, k - coefficient, considering properties of substance, temperature and length of capillary.

EFFECT: increased speed and quality of control over alternation of properties of substances during batching process and amount of batched substance per time unit for substances of broad volatility spectrum.

1 dwg

Description

The invention relates to the field of analysis of materials by determining their chemical and physical properties, specifically to obtaining or preparing samples for research by diluting, spraying or mixing them.

Known dispensers for the flow of a mixture of a pair of substances - air to create a vapor-air mixture with a given concentration, containing an evaporator chamber for diffusion of molecules from the liquid-vapor interface into the air stream and a fitting for connection to the air stream. For example, "Dispenser flow mixture of a pair of substance-air to create a vapor-air mixture with a given concentration" according to the patent of the Russian Federation for the invention No. 2219517, IPC G 01 N 1/22, G 01 N 5/04, G 01 N 7/12, B 01 D 53/22, 2003

A known dispenser consists of an evaporator chamber for evaporating substances with high volatility or a chamber with an increased inner diameter for evaporating substances with low volatility, screwed onto the lid chamber with a channel for introducing vapor of the substance and two fittings for connection to the air stream. All parts of the dispenser are made of light, mechanically strong material - duralumin. The small mass of the dispenser itself suggests the possibility of gravimetric control of the dosed substance per unit time according to the decrease in the mass of the dispenser with the substance.

To create a vapor-air mixture of a low-volatility substance, an evaporator chamber with an increased inner diameter is used to increase the surface area of evaporation of the liquid substance. So the chambers of the metering evaporator used for dispensing substances with a wide range of volatility have different internal diameters, for example 10 mm for substances with high volatility (sarin, soman, lewisite, mustard gas), 14 mm for substances with low volatility (V _x ).

For sealing the fittings with plugs, for example, when weighing the dispenser, a threaded connection is used. Before starting work, substance is poured into the chamber of the dispenser evaporator, the dispenser is sealed with a fluoroplastic gasket, and plugs are screwed onto the fittings. Next is the initial weighing of the dispenser with the substance.

Then the dispenser is installed in an air thermostat. After removing the plugs from the fittings, the inlet fitting is connected to an air flow inducer, and the outlet fitting is connected to a chamber or pipe to create a vapor-air mixture.

To control the amount of the dosed substance per unit time by the gravimetric method, a repeated weighing of the substance is carried out through a fixed period of time. The dispenser is disconnected from the air stream, and the fittings are sealed.

After assessing the loss of a substance, both visual and analytical control of the change in the state of the substance in the dispenser is possible, which is especially important for easily hydrolyzable substances or substances having a complex composition.

A disadvantage of the design of such dispensers is the impossibility of an operational qualitative and quantitative assessment of the properties of the vapor-air mixture. This is because the gravimetric method provides for the initial weighing of a dispenser with a substance on an analytical balance with an accuracy of tenths of a milligram, and then a repeated control weighing of the substance is performed. Thus, it is not possible to control the change in the properties of the substance and the amount of the dosed substance during the dosing process. Such control requires a long time, including the time of direct receipt of the vapor-air mixture and the time for its deposition from the walls of the evaporation chamber before final weighing.

These disadvantages are eliminated in diffusion batchers with transparent walls of the evaporation chamber.

The closest in technical essence to the claimed device is a dispenser made of glass (E.A. Peregud, D.O. Gorelik. Instrumental methods for monitoring atmospheric pollution. L .: Chemistry, 1981, p.297). In it, liquid vapors diffuse through a thin capillary into the dispenser housing and mix with a stream of clean air.

With undoubted advantages, this dosing device has several disadvantages: the fragility of the glass structure, because it is made of glass as a whole; low concentration of the created vapor-gas mixture and its dependence not only on the pressure of the saturated vapor of the substance, but also on the diameter of the capillary used; for each of the substances with a wide volatility spectrum and for each concentration created, an individual batcher design is required that meets the specified requirements, and the determination of diffusion coefficients for calculating the batcher design elements is associated with significant difficulties, as well as the difficulty of filling and changing the metering substance.

The objective of the invention is the creation of stable composition for a long time gas-vapor mixtures for substances with different volatilities.

The technical result that can be obtained by using the invention is to develop a capillary dispenser for creating vapor-gas mixtures of a wide range of volatility with operational control of changes in their physicochemical properties during dosing, as well as the amount of dosed substance per unit time.

The problem is achieved in that the dispenser consists of an evaporator chamber and a mixing chamber, while the evaporator chamber with the metered substance is made in the form of a cylindrical glass vial with interchangeable nozzles and capillaries of various flow cross-sections to create vapor-gas mixtures with different volatility in a wide concentration range and forms mixing chamber detachable connection.

The essence of the utility model is illustrated in the drawing, where:

1 - chamber of the evaporator;

2 - mixing chamber;

3 - fluoroplastic gasket;

4 - glass vial;

5 - interchangeable nozzles;

6 - capillary;

7 - dispenser cover;

8 - fitting;

9 - a stub.

The proposed dispenser consists of a chamber of the evaporator 1 and a mixing chamber 2, interconnected by a threaded connection. To ensure the tightness of the threaded connection of the parts of the dispenser, a gasket 3 of fluoroplastic is provided.

The chamber of the evaporator 1 is designed to accommodate the dosing substance in such a way that its internal volume is divided into two cavities: gas and liquid (dosed substance). It is made in the form of a cylindrical glass vial 4. This embodiment of the chamber of the evaporator 1 has high strength characteristics and allows you to monitor the processes taking place in it, for example, color, transparency, the presence of sediment, process dynamics, etc.

In the neck of the vial 4, interchangeable nozzles 5 and capillaries 6 of various passage sections are installed. The capillary 6 is rigidly fixed in the nozzle 5 and sealed. A set of capillaries 6 allows you to create vapor-gas mixtures with different volatility in a wide range of concentrations.

The mixing chamber 2 is a lid of the dispenser 7 with an internal hollow cavity, into which a capillary 6 is inserted in the center, and two fittings are installed at the edges 8. One of them is designed to supply air from an external source of compressed air, and the other to exhaust the vapor-air mixture. In the initial state, to seal the dispenser as a whole, plugs for 9 fittings are provided.

The operation of the capillary dispenser is based on the thermal diffusion method, based on the mixing of the target gas and diluent gas flows. In this case, the flow of the target component is determined by the geometric parameters of the capillary 6 in the nozzle 5, as well as by the temperature regime of the dispenser.

The diameter of the capillary 6 is determined from the equation of performance

and is determined by the formula

where ρ is the mass concentration of the target component in the gas mixture,

Q is the flow rate of the diluent gas (gas mixture),

ρ _∑ is the mass concentration of the vapor-gas mixture,

V is the volume of the vapor-gas mixture enclosed in capillary 6,

d is the diameter of the capillary 6,

l is the length of the capillary 6,

k is a coefficient taking into account the properties of the substance, temperature and capillary length 6, because all experiments are carried out with its constant value.

Thus, by varying the diameter of the capillary 6, it is possible to change the performance of the dispenser in a wide range of values.

The capillary dispenser of gas-vapor mixtures works as follows.

Before work, you must perform the following operations:

- remove the plugs 9 from the fittings 8 and connect them to the corresponding highways;

- pick up nozzles 5 with capillary 6 of the required performance;

- disconnect the chamber of the evaporator 1 from the mixing chamber 2;

- install nozzles 5 with capillary 6 into the neck of vial 4;

- fill vialla 4 with a dosing substance;

- install a fluoroplastic gasket and attach the evaporator chamber 1 to the mixing chamber 2.

During operation, the pairs of the dosed substance diffuse from the surface of the liquid in the chamber of the evaporator 1 into the air space of the vial 4 and are introduced into the air stream through the capillary 6, thereby achieving the dosage of the vapor-air mixture stream. The amount of vapor of a substance in a mixture of vapor - air depends on the volatility of the substance and on the temperature regime of evaporation.

The device of a capillary dispenser of gas-vapor mixtures allows you to visually control the change in the properties of the substance during the dosing process. The amount of dosed substance per unit time is determined by the parameters of the installed capillary 6, which does not require disassembly and subsequent assembly of the dispenser.

To create a vapor-air mixture with a given concentration with other dosing substances, it is necessary either to connect another vial 4 with this substance or pour a new dosed substance into the existing vial 4, while replacing the nozzle 5 with the capillary 6 required for this substance.

The advantage of the proposed capillary dispenser of gas-vapor mixtures is the possibility of prompt and high-quality control of both changes in the properties of the substance during the dosing process and the amount of dosed substance per unit time for substances with a wide range of volatility.

Claims (1)

Capillary dispenser for vapor-gas mixtures, consisting of a mixing chamber with inlet and outlet fittings, an evaporator chamber with a metered substance and a capillary, characterized in that the evaporation chamber with a metered substance is made in the form of a cylindrical glass vial with interchangeable nozzles and capillaries of various passage sections for creating vapor-gas mixtures with different volatility in a wide range of concentrations and forms a detachable connection with the mixing chamber, while the diameter of the capillary d is determined by rmule

where ρ is the mass concentration of the target component in the gas mixture; Q is the flow rate of the diluent gas of the gas mixture; ρ _Σ is the mass concentration of the vapor-gas mixture; k - coefficient taking into account the properties of the substance, temperature and the length of the capillary.