SU1345107A1 - Corona charge humidity converter - Google Patents

Abstract

This invention relates to a measurement technique used to monitor parameters of gaseous media. The purpose of the invention is to significantly improve the stability of the moisture characteristic and increase the accuracy of moisture measurement. The corona discharge humidity transmitter consists of two coaxially arranged cylindrical electrodes, between which a strong electric field is created, leading to the formation of a stable corona discharge near the central electrode, the current value of which depends on the humidity of the gaseous medium. An additional system of detection electrodes in the form of mesh cylinders, equipped with its own electric field and located outside the zone of action of a corona discharge, is introduced into this converter. 2 Il. i (L with 4 SP

Description

 13

The invention relates to a measurement technique designed to monitor the parameters of gaseous media, including air, and, in particular, relates to corona discharge ionization hygrometers, whose operation is based on the dependence of the corona discharge current on the concentration of water vapor in the analysis environment.

The purpose of the invention is to increase the stability of the moisture-metric characteristic of a corona-discharge ionization hygrometer and to increase the accuracy of the measurement of the moisture content of the monitored gaseous media.

FIG. 1 shows a diagram of the device; in fig. 2 is a graph of relative humidity versus crown current.

The design of a hygrometer of this type contains corona electrodes 1 and 2, a system of detecting electrodes 3 and 4, located at a distance R from the corona electrode, the corona current meter 5, which contains electrometric

amplifier, source 6 additional 30 change in process efficiency

the voltage by which a three-field field is created by the voltage E., the high-voltage source 7 of the stabilized voltage. This design of the hygrometer eliminates the electron component of the corona current and treats the system of corona electrodes (I and 2) as an adjustable ion source whose power is a stable function of a wet network controlled gaseous medium. The number of ions N supplied by this source to the surface of a cylinder of radius R is calculated using the ratio

(one)

, + / lUj / qR

de JU is the difference between the magnitude of the applied voltage and the voltage of the onset of corona development; the corners of the corona electrodes;

coefficient of proportionality;

the charge of an elemental ion.

Go.K

BUT

q

Have

7

The dependence of N on humidity (gaseous medium is determined by the formal dependence / iU (if}. With increasing L /, the concentration of ions formed in the discharge gap increases due to the capture of thermolyzed electrons by gaseous medium molecules. Moreover, water molecules almost do not capture thermolyzed electrons, but only only initiate these processes, playing the role of the third particle, which serves to conserve the amount of energy in the processes of interaction fl + Oj + H OJ. As a result, a stable dependence of the concentration of ions, n Following the cylinder surface of radius R, from the humidity of the gaseous medium, which is the basis of the operation of the ionization hygrometer of the corona discharge.

A change in the pressure and temperature of the controlled gaseous medium leads to a rather strong change in the magnitude of the corona discharge current, which is associated with a change in the mean free path, resulting in

impact ionization. Therefore, a change in the pressure and temperature of the gaseous medium is related to destabilizing the operation of the ionization hygrometer factors that require additional control in the process of measuring the humidity of such hygrometers.

Claims (1)

Invention Formula A corona discharge humidity transmitter containing coaxially arranged cylindrical electrodes connected to the source -. strands and included in the recording system, characterized in that, in order to improve the stability of the moisture metering characteristic and increase the measurement accuracy, two additional electrodes are introduced in the discharge gap in the form of high-transparency mesh cylinders arranged parallel to the main ones connected to an additional source voltage located outside the corona. 20 1 (0 60 FIG. 2 Compiled by E, Rozhkovska Editor L. Povhan Tehred M. Didyk Proofreader S. Cherni Order 4913/43 Edition 775 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 80 G%, o / mon.Al.