SU593172A1 - Method of preparing gas mixtures for testing atmosphere pollution-monitoring instruments - Google Patents

Description

are known. Consequently, at each time point it is possible to determine the concentration value at the input to the instrument. Then, at certain points in time, the known volume of this mixture is investigated in a calibrated instrument and its calibration characteristic is constructed.

The disadvantage of this method is that the concentration at the output of the mixing volume changes from large values to smaller ones, which introduces significant distortions in the exponential law of its change in the microconcentration region due to the process of LT sorption from the walls of the apparatus.

The aim of the invention is to improve the accuracy of gas mixtures in the area of microcentration by reducing the effect of sorption processes, for which a gas mixture is proposed to be transferred face-to-length with a constant carrier gas through the mixing tank before being fed into the turntable. Such a solution allows an increase in the concentration value at the entrance to the turnable device from zero to a known law, which reduces the process of desorption from the walls of the equipment.

A known amount of the control substance is dosed into a mixing tank Vi filled with a carrier gas. Then the tank Y is blown with a different flow rate of carrier gas Q and the second inlet of the mixing tank 1/2, as well as filled with a gas carrier, is fed into the inlet. Concentration C in tank U will increase in time according to the law.

f.

F,

Vo

WITH,

Q

QL

Q

V,

V.

Vi

Vi

long

where GO is the capacitance concentration in Y at time 0.

Р О

for V, I / ,.

As can be seen from the above expressions, the concentration of Cx increases with time according to the law, whose parameters are lime.

The proposed method is implemented, for example, by the scheme shown in the drawing, where 1 -

a carrier gas cylinder, 2 — reducer, 3 — carrier gas preparation unit, 4 — Di-metering valve with a metering volume V, 5 — crane, a DZ with a mixing capacity Vi, 6-

Oz-dosing crane with a UZ-mixing capacity, 7 - a cylinder with a control substance, 8 - a reducer.

From the carrier gas cylinder, the gas enters the carrier gas preparation unit through a reducer, where it is cleaned of impurities. With the help of this cylinder, the flow through the dispensers DI, D2, DZ is established and maintained into the graduated or calibrated chromatograph. At time 0, the dispenser Dif {oz the volume V of the control component into the mixing tank Vb. The concentration of the binary mixture in the tank Ub, being blown by the carrier gas through the batcher B3 into the chromatograph, varies exponentially. At the moment of time tx, the concentration of the control substance in the tank Vz is equal and can be calculated using the formula 2. In the volume of the ultrasound the concentration of the control substance is zero. At time ti volume V using a dispenser

is introduced into the flow of the carrier gas and the binary mixture begins to flow into the instrument being turned. The law of concentration change in the ultrasound volume is described by equations (3) and (4).

Claims (3)

1. Kollerov DK Metrological basis of gas-analytical measurements. M., “Standard, 1971, p. 12-23. 2. Butko V. M. Didovicher E. M., Koz V. G., Rozhenov M. S., Measuring equipment, No. I, 1974, p. 33. 3.Gas. Ghromatography, I960, Butter Worths, p. 26-27. to the instrument