Device for preparation of gas-vapor mixture

 

The invention relates to the field of analytical instrumentation and can be used in the calibration and calibration of gas analyzers. Device for preparation of gas-vapor mixtures contains a vessel to saturate the gas vapors of a substance, a device for dilution of the gas mixture and the gas line to enter the diluted gas mixture in the calibrated detector, which is equipped with a detector and the pump flow rate. In the device there is an additional vessel for mixing, coupled with the vessel for saturation and with adjustment for dilution, and the additional vessel for mixing provided with a channel for supplying a gas into the vessel, which has controlled shutoff valve. The technical result is improved stability of the concentration of the calibration substance in prepared gas mixture at low concentrations of substances. 8 C.p. f-crystals, 3 ill.

The invention relates to the field of analytical instrumentation and can be used in the calibration and calibration of gas analyzers.

A device for cooking gas mixture containing vessel to saturate the gas pairs substances, partially filled with liquid substances is of dilution gas mixture, installed in the gas line to output vapor-gas mixture from the vessel, a gas line for supplying a gas flow device for the dilution gas line to output vapor-gas mixture in the calibrated detector and the pump flow rate (see, for example, Guidance on the use of the generator controlled concentrations of substances in the air of the firm Cavcit Ltd, UK, 1997).

A disadvantage of the known device is the limited range of substances that can be used as a source for preparation of calibration gas-vapor mixtures, as only a very limited number of substances known exact values of the elasticity of steam, which is the calculation of the concentration of the substance in the calibration mixture.

The closest to the technical nature of the present device is a device for cooking gas mixture containing vessel to saturate the gas pairs substances, partially filled with the liquid substance, a gas line for supplying gas into the vessel, a gas line for output vapor-gas mixture from the vessel, a device for dilution of the gas mixture that is installed in the gas line to output vapor-gas mixture from the vessel, a gas line for a stock mixture in the detector, the detector is non-destructive type and consumption booster installed in the gas line to enter the diluted gas mixture in the gas analyzer (see RF Patent 2148822).

The specified device is adopted for the prototype, allows to obtain a gas mixture of a wide range of substances and does not require calculations using data on the characteristics of the substance or environmental parameters.

The disadvantages of the known devices appear when creating a calibration mixtures with low (up to 100 mg/m3) concentration calibration substances. The problem is that the vapor concentration of the substance in the vessel varies in time. This leads to an increase in the volatility of the concentration of the calibration mixture. Upon receipt of the concentrations in the hundreds of mg/m3the amount of instability in the percentage remains low, in the range of concentrations in the tens of mg/m3for volatile substances the amount of instability can reach 10% or more.

The objective of the invention was to improve the stability of the concentration of the calibration substance in the gas mixture at low concentrations of substances.

This task is solved in that the device for making steam and gas line for supplying gas into the vessel, gas line for output vapor-gas mixture from the vessel, a device for dilution of the gas mixture, the gas line to enter the diluted gas mixture in the calibrated detector, the detector and the consumption booster installed in the gas line to enter the diluted gas mixture in the calibrated detector, in which according to the invention an additional vessel for mixing with the gas inlet connected to a gas line for output vapor-gas mixture from the vessel to saturate the gas vapors of the substance, and a gas outlet connected to a device for dilution of the gas mixture.

In a preferred embodiment, the additional vessel for mixing provided with a channel for supplying a gas into the vessel, which has controlled shutoff valve.

In one possible embodiment of the device additional consumption booster, is installed in the gas line connecting the vessel to saturate with an additional vessel for mixing.

In another alternative embodiment, the device introduced in additional controlled shut-off valve installed in the gas line connecting the vessel to saturate with additional southgermany vapor in the gas in the secondary vessel for mixing. To this end, the vessel for mixing may be provided with a channel selection part of the vapor-gas mixture from the vessel and the channel to return this part of the mixture in the vessel, forming a closed gas circuit, which has a detector for controlling the water vapor content in the vessel for mixing and stimulate consumption.

Another distinctive feature of the device is that it introduced a microprocessor control unit, one input of which is connected to the detector of the water vapor content in the vessel for mixing, and one of its outputs connected to the drive controlled shut-off valve mounted in the channel for supplying a gas into the vessel for mixing. One of the control outputs of the microprocessor control unit is connected with consumption booster installed in the gas line connecting the vessel to saturate with the vessel for mixing or actuator controlled shut-off valve, which can be installed instead of the pump flow.

The invention is illustrated by drawings.

In Fig.1 presents a schematic diagram of the proposed device.

In Fig.2 shows a schematic diagram of a variant of execution of the device with additional pump flow rate at the inlet in the vessel for mixing.

Apana at the entrance to the vessel for mixing.

The device comprises a vessel 1 for saturation of gas pairs substances, partially filled with the liquid substance 2. The vessel 1 is supplied by a pipe 3, is blocked by the membrane 4 of the self-sealing material such as silicone rubber. The vessel 1 has a gas line 5 for supplying a gas into the vessel. Gas line 5 is connected to the gas source 6, for example, atmospheric air, and it installed the absorber 7 preventing mechanical impurities (e.g. dust) and interfering substances (e.g. water vapor). The vessel 1 has a gas line 8 to output vapor-gas mixture from the vessel connected to a gas inlet 9 additional vessel 10 for mixing. The vessel 10 for mixing provided with a channel 11 for supplying an additional gas flow, which has managed the shut-off valve 12 and the absorber 13 preventing mechanical impurities and substances. The vessel 10 for mixing has also exit 14, which is connected via a gas line 15 with the device 16 to dilute the gas mixture. The fixture 16 to dilute the gas mixture has a gas channel 17 for the supply of the diluent gas, such as atmospheric air, in which you installed the controller 18 of the gas and the absorber 19 preventing mechanical impurities and substances. Lighting the art to calibrate the detector (not shown), which includes a detector 21 non-destructive type (for example, a photo-ionization detector) and the consumption booster 22. The vessel 1 for gas saturation vapor of the substance provided with a heat-shielding cover 23 to prevent sudden fluctuations in temperature inside the vessel 1 while changing the ambient temperature (e.g. room temperature).

The device operates as follows.

In the vessel 1 before starting work, introduce a metered quantity of a liquid substance, such as acetone. The input of the substance into the vessel 1 through the pipe 3 using the dosing syringe (not shown), the needle of which pierce the membrane 4 of the self-sealing material. In the vessel above the surface of the liquid substance after some time, set the equilibrium vapor concentration of the substance in the air. Then actuate the booster 22 consumption. The flow of gas (air) is sucked into the device through the inlet gas line 5 passes through the absorber 7, where it is freed from mechanical impurities and impurities interfering substances, and enters the vessel 1, where the saturated vapors of the substance 2. The flow of the gas mixture formed in the vessel 1, the gas line 8 enters the vessel 10 for mixing.

In a dependent is the first line 11, can be either open (when receiving low concentrations) or closed (when receiving large concentrations).

When you open shut-off valve 12, the flow of gas (air) is purified by the filter 13 and through the valve 12 to the gas line 11 enters the vessel 10 for mixing where it mixes with the steam and gas mixture flowing out of the vessel 1 for saturation. Next, the resulting gas-vapor mixture in the gas line 15 enters the device 16 for dilution, where it is diluted with a gas (air) flowing through the gas line 17 through the filter 19 and the flow regulator 18. The flow rate of dilution gas (air) is controlled by the flow regulator 18. Gas-vapor mixture goes into the detector 21 non-destructive type, which measures the concentration of a substance in a mixture, and through the booster 22 flow is directed into the calibrated detector (not shown).

Setting the desired value of the concentration is performed using the controller 18 of the gas flow, and by opening and closing of the shutoff valve 12.

In the process, fluctuations in the pressure of the vapor in the tank 1 for saturation smoothed when the movement of the mixture through the gas line 8 and the vessel 10 for mixing, and concentration of substances is mg/m3for such volatile substances as benzene and acetone.

Presented on Fig.2 schematic diagram of another possible form of execution of the device differs from the above in that it introduced an additional booster 24 consumption, installed in lines 8 to output vapor-gas mixture from the vessel 1 to saturation, an additional detector 25 to control the content of the substance in the vessel 10 for mixing and microprocessor unit 26 controls. When one of the control inputs 27 microprocessor unit 26 is connected to the detector 25 substances, one of the control output 28 is connected with additional booster 24 consumption, and the second control output 29 is connected with the shut-off valve 12 installed in line 11 for supplying a gas into the vessel 10 for mixing.

A feature of this variant of the device is the ability to maintain the necessary concentration in the vessel 10 for mixing. The detector 25, which measures the concentration of a substance in a vessel 10 for mixing, produces an electrical signal which is fed to the input 27 of the microprocessor unit 26, which compares the measured concentration with a given and in case of deviation produces a control signal to the pan 12, including turning them off in such a way as to maintain the concentration of the vapor-gas mixture in the vessel 10 for mixing at the specified level. This allows you to maintain the concentration in the vessel 10 for mixing in accordance with the required concentration at the outlet, significantly expanding the range of the resulting gas-vapor mixtures.

Is depicted in Fig.3 schematic diagram of one possible form of execution of the device differs from that described above (Fig.2) the fact that instead of an additional booster 24 consumption has additional control shutoff valve 30. When the vessel 10 for mixing provided with a channel 31 for selecting part of the vapor-gas mixture from the vessel 10 and the channel 32 to return this part of the mixture in the vessel 10 forming a closed gas circuit, in which you installed the detector 25 to control the content of the substance in the vessel 10 and the booster 33 flow to circulate selected part of the gas mixture.

A feature of this variant of execution of the device is that the concentration of the substance in the vessel 10 for mixing is governed by the microprocessor unit 26 by opening and closing shut-off valves 30 and 12 depending on the readings of the detector 25, the controlling maderista for the preparation of gas-vapor mixtures, containing vessel to saturate the gas pairs substances, partially filled with the liquid substance, a gas line for supplying gas into the vessel, a gas line for output vapor-gas mixture from the vessel, a device for dilution of the gas mixture, the gas line to enter the diluted gas mixture in the calibrated detector, the detector is non-destructive type and booster gas flow, installed in the gas line to enter the diluted gas mixture in the calibrated detector, characterized in that it introduced an additional vessel for mixing with the gas inlet connected to a gas line for output vapor-gas mixture from the vessel to saturate the gas pairs substances, and gas outlet connected to a device for dilution of the gas mixture.

2. The device under item 1, characterized in that the additional vessel for mixing provided with a channel for supplying a gas into the vessel, which has controlled shutoff valve.

3. The device under item 1 or 2, characterized in that it introduced additional consumption booster, is installed in the gas line connecting the vessel to saturate with an additional vessel for mixing.

4. The device under item 1 or 2, characterized in that Thu is to saturate with an additional vessel for mixing.

5. The device under item 1, or 2, or 3, or 4, characterized in that it is provided with a detector for controlling the water vapor content in the gas in the secondary vessel for mixing.

6. The device under item 5, characterized in that the receptacle for mixing provided by the channel selection part of the vapor-gas mixture from the vessel and the channel to return this part of the mixture in the vessel, forming a closed gas circuit, which has a detector for controlling the water vapor content in the vessel for mixing and stimulate consumption.

7. The device under item 5 or 6, characterized in that it introduced a microprocessor control unit, one input of which is connected to the detector of the water vapor content in the vessel for mixing, and one of its outputs connected to the drive controlled shut-off valve mounted in the channel for supplying a gas into the vessel for mixing.

8. The device according to p. 7, wherein one of the control outputs of the microprocessor control unit is connected with consumption booster installed in the gas line connecting the vessel to saturate with the vessel for mixing.

9. The device according to p. 7, wherein one of the control outputs of the microprocessor control unit connected to the drive managed zaporog the

 

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