A mechanical hygrometer is a device that is used to measure air humidity. Since this indicator is very important in human life, hygrometers are widely used at home and in industries. Many varieties of device models are known.
The modern market offers these devices, combining them with other devices, in particular, with thermometers or watches.
Hygrometer Classification
Devices for measuring humidity are divided according to the principle of action into three groups: mechanical, electrical and condensation.
Mechanical hygrometer can be hair, film, weight.
The principle of operation of a hair device is based on the properties of changing the length of fat-free hair depending on the humidity of the environment. In a special frame, hair is stretched, which is connected to an arrow that reacts to a change in its length. Indications are displayed on a scale.
Such devices are used at meteorological stations; they are quite accurate and reliable.
A mechanical film hygrometer is based on the properties of a film that responds to increasing and decreasing humidity. This changes the surface area of the film. The arrow reacts to changes in the position of the film center, which is displayed on the scale.
The weight hygrometer uses a hygroscopic substance that fills the tube system made in a U-shape.
The operation of condensation hygrometers is based on establishing the dew point, which is determined by the temperature of a special metal mirror during cooling, at the moment traces of condensate appear on its surface.
Electric hygrometers are based on the properties of electrolyte. Instrument glass is coated with an electrolyte layer with hygroscopic properties. Changes in air humidity affect the electrolyte concentration and its resistance.
Application of hygrometers
The industry produces hygrometers depending on the scope of application: industrial and domestic. Electronic models are considered the most popular. Usually they are equipped with a thermometer and are called a "hygrometer-thermometer." This is convenient because the display shows humidity and air temperature. Models of devices with remote electrodes are universal.
The importance of measuring air humidity
Scientists have proved that low humidity, combined with high air temperature, negatively affects the human body, worsening its functional work and weakening the immune system. The optimal indicator of humidity for a person is considered to be its value above 40%.
Hygrometer mechanical, psychometric and others are widely used in medicine and in everyday life.
A modern psychometric device is designed to study the readings of relative humidity and air temperature in various rooms for the storage of materials, poultry, silk farms and warehouses. The devices are available in various modifications and vary in temperature range and humidity indicators depending on the application.
The psychometric hygrometer is designed in such a way that the temperature scale and two thermometers are fixed on a plastic base, and studies are carried out according to the psychometric table. The thermometric fluid of this device is toluene or mercury.