Hygrometer mechanical and other devices
A mechanical hygrometer is a device thatUsed to measure the humidity of air. Since this indicator is very important in human life, hygrometers have found wide application at home and in industry. There are many varieties of models of the device.
Classification of hygrometers
Devices for measuring humidity are divided according to the principle of action into three groups: mechanical, electrical and condensing.
Hygrometer mechanical can be hair, film, weight.
The principle of the hair device is based onproperties of the change in the length of fat-free hair, depending on the moisture content of the medium. In a special frame, stretch the hair, which is connected to the arrow, which reacts to the change in its length. Indications are displayed on the scale.
Such devices are used at meteorological stations, they are quite accurate and reliable.
The film hygrometer is mechanical based onproperties of the film, which reacts to rising and falling humidity. The surface area of the film changes. The arrow responds to changes in the position of the film center, which is displayed on the scale.
In the weight hygrometer, a hygroscopic substance is used that fills the system of tubes made in a U-shape.
The operation of condensation hygrometers is based onthe establishment of the dew point, which is determined by the temperature of a special metallic mirror upon cooling, at the moment of the appearance of traces of condensate on its surface.
Electrical hygrometers are based on propertieselectrolyte. The glass of devices is covered with a layer of electrolyte with hygroscopic properties. The change in air humidity affects the concentration of the electrolyte and its resistance.
Application of hygrometers
Industry produces hygrometers in dependencefrom the scope of application: industrial and household. Electronic models are considered the most popular. Usually they are supplied with a thermometer and are called a "hygrometer-thermometer". This is convenient, because the display shows the humidity and air temperature. Models of devices with remote electrodes are universal.
Importance of measuring air humidity
Scientists have proved that low humidity in combinationwith a high air temperature, adversely affects the human body, worsening its functional performance and weakening immunity. The optimum indicator of humidity for a person is its value above 40%.
A modern psychometric device is intendedfor studies of indications of relative humidity and air temperature in various storage areas for materials, poultry, silk farms and storage facilities. The devices are available in various modifications and differ in temperature range and humidity indices depending on the application.
The psychometric hygrometer is designed in such a wayin the manner that the temperature scale and two thermometers are fixed on the base of plastic, and the studies are conducted according to the psychometric table. The thermometric fluid of this device is toluene or mercury.
