SU594447A1 - Gas moisture transducer - Google Patents

Description

(54) GAS MOISTURE CONVERSION.

one

The invention relates to the field of measurement technology and can be used for continuous measurement of the moisture content of vapor-gas mixtures with temperatures up to industrial installations, drying chambers, etc.

Humidity transducers are known, the principle of action of which is based on measuring the psychrometric difference in temperature of dry and wet thermometers. However, in known transducers, the measurement error strongly depends on the pollution of the wick that feeds the wet thermometer with dust, solid particles and water-soluble salts | l3.

The closest technical solution to the invention is a gas moisture converter / containing a cylindrical body with a spray chamber, a heat exchanger, and wet and dry sensing elements 2. In this converter, water is sprayed by breaking the medium through the converter. The wet resistance thermometer is located in the immediate vicinity of the spray booth, as a result, until

sprayed water along the thermometer with resistance will decrease its temperature to a certain value proportional to the humidity measured. environment. Thus, a temperature gradient occurs along the length of a wet resistance thermometer. As a result, the measured temperature will be higher than the true value, which introduces a large error in the measurement of humidity.

The invention of the invention is to improve the accuracy of measurement and improve the dynamic characteristics by measuring the temperature in the zone of dynamical equilibrium.

For this, the wet sensing element is located at a distance of 2.5 to 3 times the inner diameter of the housing from the spray booth, the inlet of which is connected to the outlet of the heat exchanger.

Claims (2)

In the process of spraying the wetting water with the measured medium, as it moves its smallest droplets from their surface, evaporation occurs and, consequently, the temperature decreases, since the vapor pressure of the saturation vapor on the droplet surface is greater than the pressure in the measured medium. When equilibrium occurs between the indicated pressures, the temperature of the drop ceases to change. This temperature is proportional to the measured humidity. At this point, the droplets will be at some distance from the spray booth in the zone of dynamic equilibrium. A thermometer placed in this zone measures the temperature of the wet thermometer. Water will not evaporate from its surface, since its pressure is in equilibrium with the vapor pressure of the medium being measured. The zone has a certain extent along the movement of the droplets, as a result of which the temperature gradient is not created on the thermometer and the measurement accuracy is improved. The position of the dynamic equilibrium zone does not depend on the change in the humidity of the measured medium and, as a result, does not reflect on the measurement accuracy. To stabilize the zone, it is sufficient to maintain the temperature of the sprayed water equal to the temperature of the medium being measured, which also does not depend on the humidity of the medium being measured and does not affect the dynamic characteristics of the converter. Due to the small mass of water droplets and their good mixing with the measured medium, the rate of change in the temperature of the aerosol mixture with changes in humidity will be large, and this leads to improvement. Hygrometer Dynamic Characteristics A general view of the proposed gas humidifier is shown. t It consists of the sensitive element 1 of the dry thermometer of the housing 2, the spray chamber 3, the heat exchanger 4, which is made in the form of a coil of a material with high thermal conductivity, the sensing element of the wet thermometer 5, fitting 6 for supplying a wetting water and a healthy ejector 7. Converter works as follows. The measurement of the medium through the air ejector 7 is sucked through the housing 2 of the converter and, washing the dry sensing element 1, flows through the throttle opening into the expansion chamber 3. Because of the high velocity of the flow of the measured medium, a spraying effect is created, thereby brought to the fitting 6 the wetting water is sucked through the heat exchanger 4, heated to the temperature of the medium being measured and sprayed. The sprayed mixture, the distance passed, washes the sensing element of the wet thermometer and is thrown through the ejector 7 to the outside. The distance P corresponds to 2.5–3 internal diameters of the body at the speed of passage of the measured medium through it, equal to 3.5 m / s. Claims of Gas Intensity Converter Containing a Cylindrical Body with a Spray Chamber, Heat Exchanger, Dry and Wet Cellular Elements, characterized in that, in order to improve accuracy and improve dynamic characteristics by measuring the temperature in the dynamic equilibrium zone, the wet sensing element is located at a distance equal to 2.5-3 internal diameters. housing from the spray chamber, the input of which is connected to the outlet of the heat exchanger. . Sources of information are taken into account in the examination: 1.Berliner M.Ag. Measurement of voidness. M., Energie, 1973, p.223 2. Top NI, Sherman M.Ya. Thermal measuring and regulating devices. Moscow, Metallurgists, 1566, p. 169.