SU636526A1 - Gas humidity determining method - Google Patents

Description

This invention relates to analytical instrumentation and can be used in the development of methods for measuring the relative humidity of gases, in excess of air.

The known method for determining the gas humidity i by the parameters of the corona discharge.

The absorption of this method is low sensitivity, the dependence of the discharge current on the composition of the gas, the need to remove the ozone formed in the gas discharge.

There is a known method for measuring humidity 2J, according to which a test object is charged from a source of DC voltage briefly short-circuited and discharged into a measuring circuit. In this case, the dependence of the absorption components of the discharge current of the dielectric on moisture content is used.

When determining the humidity of gases using this method, the discharge characteristics of the pre-charged

This method is the closest technical solution to the pre-wired environment.

However, the measurement of the absorption ratio of the discharge current of the sorbent. Is impractical because it depends not only on the humidity of the air, but also on such interfering factors as temperature, distribution pattern of inhomogeneity, electrode potential

The purpose of the invention is to improve the accuracy of determining the humidity.

The goal is achieved by the fact that when a de sorbent is discharged, a bias current is measured, its relaxation time is found - the time interval during which the current decreases by e times from the initial value, and the value of the gas relaxation time is determined by the gas humidity.

The essence of the method is as follows. When discharging a sorbent, which was under the influence of a constant electric field, almost instantaneously, the so-called geometrical capacitance 63 is caused by the excitation of the vacuum between the electrodes and the deformation-polarization. Next, the capacitance of the capacitance formed by the double electric IMC layer at the electrode – material interface occurs. surfaces. The absorption component of the discharge current is relatively slow (G 10–10 s). PRI me R As primary transducers, flat parallel plates were used. Slippers were 5x5x2 mm in size with electrvs deposited on counter-faced end faces.

Reference BnaKiioC values,%

Humidity values determined by the proposed method 34.2 56.1 72.8 79.9 89.593.2 Absolute error in determining the humidity of air,%

Relative error,%

When used as a Bwlci1 {- Shz1, depending on humidity, recurrence time of the displacement current, the accuracy of the determination is increased due to the removal of the interfering values determined in this case. The measurement time decreases from 6О-1ОО to ZO-9O ms both by reducing the time of observation and by eliminating the preliminary discharge.

Claims (1)

1.Berliner M, A, Measuring moisture content, m, Energie, 1973, p. 309312. 2, Author's certificate of the USSR No. 123343, M. class. 01 M 27/22, 1959, 4. The transducer charged from a constant-voltage source (I) for 2 minutes, then disconnected from the voltage source using a switch and connected to an indicator circuit. To observe the shape of the discharge curve and determine the relaxation time, a C 1-5 4 pulsed oscilloscope was used. Reference moisture values were created using saturated solutions of hygroscopic salts. Comparison of the results obtained from the found conversion function with the reference moisture values showed (see table) that the relative error does not exceed 4.1%.