home · Other · Which room hygrometer is better to buy: classification, description, principle of operation. What is a hygrometer How does a hygrometer work? What is it used for?

Which room hygrometer is better to buy: classification, description, principle of operation. What is a hygrometer How does a hygrometer work? What is it used for?

In construction, mechanical engineering, agriculture, production and even in everyday life, for various reasons, it is necessary to measure the humidity of gases and materials.

For these purposes, a moisture meter is used, as well as its popular subtype - a hygrometer.

The latter can be divided into many types, depending on the method of measuring humidity and various design features.

It is interesting that this is a device that is simple from a technical point of view, but extremely useful, and sometimes simply necessary from a practical point of view.

Purpose of hygrometers

Initially, a hygrometer, which is also sometimes called a hygroscope, was exclusively laboratory equipment designed to literally determine the amount of moisture in gases.

Today, this name is given to devices that can determine:

  • The absolute humidity of a gas mixture, that is, the density of water vapor present.
  • Relative humidity is the ratio of the amount of water contained in a gas mixture at its specific temperature to the maximum possible amount of water in the same mixture at the same temperature.
  • Dew point - the temperature at which the saturation of a gas mixture with water vapor becomes maximum, if, under other conditions, equal indicators be constantly contained in this mixture. To put it simply, this is the temperature at which moisture condensation begins at a certain pressure value.

It is interesting that the readings of one type of hygrometer can be easily converted into the results of another through simple calculations, or by using ready-made special tables, since all three given values ​​are related.

Also impressive is the number of most different methods taking readings.

For example, some are based on the conductivity of air, others on the content of salts and polymers.

Most hygrometers are designed to determine the humidity of a well-known gas mixture - air.

This is important both in Everyday life, and in the most different areas human activity.

It has been proven that excess or insufficient humidity has Negative influence on human health, so it is important to adjust its level to ensure comfort.

A hygrometer is often used by builders when performing plastering and painting works to check air humidity for compliance with building codes.

The same applies to wallpapering, laying laminate flooring, and caring for already laid parquet.

Over time, humidity meters began to be called hygrometers not only gas mixtures, but also various materials.

For example, on sale you can find models for wood and other building materials, including hardening ones, such as concrete.

Others are designed specifically for grain.

Still others are used to analyze petroleum products and, in fact, the oil itself.

As you can see, moisture meters are used everywhere, and there are many types on the market.

Design, characteristics and principle of operation

A modern hygrometer consists of a housing, inside of which the actual mechanism that determines humidity is hidden, the design of which depends on the type of device.

Electronic models require a power source to operate, for example, batteries, which are also hidden in the case; such options are called wireless.

There are also wired hygrometers, where the indicator is located at the end of the wire, which allows you to take measurements in hard-to-reach places.

Network models of this device that operate from an electrical network are also called wired.

There are also battery-powered versions of the devices.

Digital hygrometers display the humidity level on a display.

Dial, that is, analog models have a pointer and a dial.

A sensor is in contact with the environment under study, which can be internal - to determine the humidity of the surrounding air, and external - to take measurements at a specific point.

Material

In the manufacture of the hygrometer housing, plastic is often used, less often metal and wood.

If the design has a dial, it closes transparent plastic or glass.

Dimensions and weight of hygrometers

It should be taken into account that hygrometers can be manufactured as separate devices, or they can be mounted in a housing with other devices, for example, as part of a home weather station.

In most cases, a humidity meter is a compact device with a wall or tabletop design.

Weather stations are usually comparable in size to wall clock and weigh up to 1 kg or more.

Desktop analog models usually have a dial with a diameter of about 80 – 100 mm.

Digital desktop instruments are comparable in size to a calculator with a height and width of 110 x 100 mm on average.

In a pocket-sized version, digital moisture meters are comparable in both appearance and dimensions to individual breathalyzers.

Metric system and uncertainty

In most cases, hygrometers determine the relative humidity of the air, and therefore the result is shown as a percentage.

In this case, the dial is marked from 0 to 100. However, this does not apply to all devices.

Thus, models showing the dew point display the result, as a rule, in degrees Celsius.

To indicate absolute humidity, the SI (International System of Units) uses kg/m3, while the absolute physical unit, CGS (centimeter-gram-second), which preceded the SI, uses g/cm3.

As for the instrument error, it greatly depends on the type of sensor used, or more precisely on its accuracy class.

Speaking about digital devices, their manufacturers usually indicate an accuracy of 1%.

However, if the model does not have a passport where the error is indicated, then you can safely doubt the hygrometer readings.

Cheap options in most cases cannot boast an error of less than 5%. This means that 70% humidity could actually be 72% or 68%.

For this reason, it is important to buy a device with a passport confirming the characteristics.

Important!

Accuracy is also affected by a dead battery, or simply poor contact.

Obviously, the most accurate devices are those with the smallest error.

Analogue hygrometers are the least accurate, therefore they are not used for important measurements; they serve more as indicators.

The error of such devices is 2% - 5%, which is in principle sufficient for everyday tasks.

A precision hygrometer is a high-precision digital instrument, the error of which does not exceed 0.1%.

Measuring depth and range

Measurement depth parameters apply only to contact hygrometers, and they depend on the length of the probes (needles) that are immersed in the material being tested.

This indicator is for hygrometers for soil, grain and other bulk materials can reach 300mm.

The scale range of hygrometers usually starts from 0% and ends at 100% humidity, sometimes 20% - 100%.

In terms of options for testing different materials, a range from 0% to the upper limits of 50% - 65% is quite sufficient.

Multifunctional instruments have several measuring ranges, depending on the materials being worked with, for example, 0% - 35% for concrete and 0% - 50% for lumber.

Additional functions

Hygrometers are often equipped with additional functionality.

Some models are combined in one housing with other measuring instruments, for example, dial or electronic thermometers.

In other words, they are capable of measuring both air humidity and temperature, and can be equipped with a clock, or vice versa - the latter acts as the main measuring device.

Other hygrometers are capable of not only displaying humidity, but also notifying about violations of the microclimate in the room.

This is possible thanks to light or sound signals, built into the device.

These functions allow you to notice the problem in a timely manner and fix it.

Some of these devices support self-installation a safe range of indicators within which the signal will not be triggered.

Manufacturers of digital hygrometers often equip their products with a pressure indicator, which makes it possible to additionally measure the absolute pressure in rooms.

Battery devices have an indication of the battery charge level and high noise immunity.

An additional function is the ability to receive and transmit information to a computer.

Among useful functions, not directly related to measurements, it should be noted the screen backlighting, which can be implemented in any way.

For some, the backlight is turned on by a button, while for others it starts automatically when the light falls below a certain level.

Pointer models are sometimes equipped with dial illumination.

Additionally, hygrometers can be equipped with an alarm clock, a calendar, and even a reading recording function, which can automatic mode mark the minimum and maximum values.

GOST

For some types of hygrometers, GOSTs have been developed that regulate the methods of their verification:

  • GOST 8.472-2013 – for piezosorption hygrometers.
  • GOST 8.547-86 regulates the verification scheme and primary standard for measuring instruments regarding gas humidity, including hygrometers and hygrographs.
  • GOST R 8.881-2015 regulates verification methods for moisture meters of lumber and wood.
  • GOST 8.519-84 – for diel-metric moisture meters of building materials.
  • GOST R 8.781-2012 – for moisture meters of grain and grain products.

The following GOSTs regulate technical requirements and conditions:

  • GOST R 8.758-2011 – for coulometric hygrometers.
  • GOST 29027-91 – test methods and general technical requirements for moisture meters of bulk and solid substances.
  • GOST 21196-75 – for neutron moisture meters.

Instruments included in the State Register of SI, used for measurements in the field of GROEI, must undergo mandatory annual periodic verification, which, like the primary verification, is carried out by special accredited bodies.

Since mechanical hygrometer models are sensitive to vibrations and shocks, after purchase they require calibration, which is performed with a special screw, usually located on the back of the case.

The meaning of this action is to place the device in an environment with a previously known humidity, after which its value is adjusted.

The quality of the hygrometer can be guaranteed, first of all, by the SI type approval certificate.

Marking

Moisture meters are marked in accordance with GOST 26828. The marking must contain the manufacturer's trademark, the designation of the hygrometer, its serial number and date of manufacture, as well as the State Register mark.

The consumer packaging, that is, the packaging, indicates the designation of the device and the trademark.

If the moisture meter has passed acceptance tests, a seal is placed on it.

Types of hygrometers and their prices

Hygrometers differ in their measurement methods into many types, so they are:

Psychrometric

The simplest options for indirectly measuring air humidity based on a decrease in the temperature of a wetted body, which acts as a temperature sensor.

A psychrometer has not one thermometer, as is the case with a classic thermometer-hygrometer combination, but two, usually toluene: dry - displays the ambient air temperature, wet - with a capillary thickening placed in a wetted wick, will always show more low temperature due to liquid evaporation and intensive cooling.

Based on the temperature difference between these thermometers, the relative humidity of the surrounding gaseous medium is determined, and for this there is a special table, which is always attached next to the thermometers on a plastic or wooden holder.

Weight

Used to find absolute humidity.

The design includes tubes with a hygroscopic substance.

There is a special pump for air intake.

Humidity is calculated based on the known volume of air, as well as the mass of the system before and after the test.

Film

A pointer instrument in which the sensor is a special organic film connected to the arrow, which changes its position relative to the dial scale when the length of the first one changes.

Hairline

Similar to the previous option, however, instead of film, it uses low-fat hair with properties similar to film models.

Electrolytic

It is based on a polystyrene, glass or any electrical insulating plate coated with a layer of electrolyte.

The electrolyte resistance directly depends on the moisture content in the air mass.

Ceramic

The sensor is a porous and solid special ceramic mixture, capable of changing its electrolytic resistance depending on humidity.

Condensation (Lambrecht)

Allows you to use a special table to find humidity at a known dew point.

Structurally, it consists of a small mirror, a device for cooling it and an ordinary thermometer.

Cooling the mirror leads to fogging, and this moment is recorded, and for the convenience of determining it, a metal ring acts as a reflection standard.

There is another type of hygrometer - electronic, which includes the following several main subspecies:

Optoelectronic

With a cooled mirror for finding the dew point, which is then heated, which allows you to determine humidity with high accuracy.

Capacitive

The design includes an oxide capacitor, the capacitance value of which is directly affected by the amount of moisture contained in the air.

Such models require mandatory periodic calibration, since the detector capacity inevitably decreases over time.

Resistive

Dependency is at the heart of the work. electrical resistance polymers and salts from the level of air humidity.

So the first parameter directly depends on the second.

According to the method of displaying information, a hygrometer can be:

Analog

A classic device with an arrow and a dial.

Digital

In most cases, a multifunctional device capable of displaying measurement results in numerical form on a built-in LCD display.

By design, the hygrometer can be:

Contact

Used to determine the moisture level of any materials.

From the name it is clear that, for example, to determine humidity wooden products, the device must be leaned against the wood with its sensors.

Vivid examples of devices of this type are an induction hygrometer - sensors are placed on the surface, as well as a needle hygrometer - sensors in the form of two needles are immersed in the material being studied.

Such equipment is used in warehouses, in laboratories when receiving building materials, in the petrochemical industry and agriculture.

Contactless

Designed to determine the humidity of gas and gas mixtures, including air.

The principle of operation is based on the ability of some substances to change any of their properties depending on the amount of moisture contained.

Hygrometers are also distinguished by their purpose, so they are for:

  • soil;
  • grains;
  • cigars;
  • building materials (concrete, wood, sand);
  • baths (saunas);
  • residential and warehouse premises.
  • weather stations;

According to the type of design, the hygrometer can be:

Desktop

Small household version with a special stand or legs for installation on a table.

Wall

It has a flat body and a hole on the back that allows it to be placed on the wall.

Can be performed in a role like household devices to display current values, and in the form of professional temperature and humidity recorders, which are also called loggers.

The latter are used to collect data, for example, on the storage conditions of raw materials in warehouses.

Portable

A digital, portable version that is small in size and designed to be carried with you and used in the field.

Stationary

Professional laboratory equipment, a set of which can weigh up to 50 kg.

A striking example is a coulometric (electrolysis) hygrometer for measuring the absolute humidity of gases by measuring the electrolysis current of water extracted from them.

In addition to the models made in an individual case, there are their multifunctional versions, that is, combined with other measuring instruments, and in terms of design they are very different.

A simple example is a thermohygrometer, which combines the functions of a thermometer and a hygrometer.

It can be either analog or electronic.

A special case of the latter is the so-called stick thermohygrometer, designed to measure humidity and temperature in hard-to-reach and narrow places due to the presence of an elongated probe movably attached to the main unit.

Classic mechanical hygrometers that do not have additional functions, can be purchased for 500 rubles, and electronic models will cost from 1 thousand rubles.

The cost of home weather stations, which include, in addition to a hygrometer, a thermometer and a barometer, starts at 5 thousand rubles, and their digital versions can cost the buyer 35 thousand rubles.

Hygrometer Manufacturers

Manufacturing various types The following are engaged in hygrometers: foreign manufacturers: Condtrol, ADA, Laserlinener, Testo, Fluke, Boneco, Beurer, Venta. As for domestic devices, the leader here is rightfully considered the manufacturer Megeon with a huge selection of hygrometers for a wide range of tasks.

A hygrometer is a device for determining the level of humidity in air and materials. It is applied as in professional field(for example, in warehouses, factories or greenhouses), and in everyday life - to maintain comfortable conditions in the apartment.

Non-contact hygrometers

A non-contact method for determining humidity was invented in ancient times: inventors constructed mechanical hygrometers using paper, wax and human hair. A little later, they began to use film as a sensor that reacts to humidity. Depending on the tension or loosening of the film, the needle shows the value on the dial. Mechanical hygrometers are reliable and durable. Today they are supplemented with barometers and thermometers - the result is a home weather station.

More modern non-contact digital hygrometers have a compact case, inside of which there is a sensor and a board, and outside there is a control panel with a display. An electronic hygrometer continuously measures humidity levels and displays numbers in real time. Additionally, it can display the ambient temperature. Among the digital models there are also full-fledged weather stations that can comprehensively control the indoor microclimate. They are installed in residential premises, libraries, greenhouses, museums, storage facilities and other places where there are strict requirements for humidity levels.

Contact hygrometers

Contact hygrometers are used to test the moisture content of materials such as wood, concrete or cardboard. The device is equipped with sensors that are applied to the surface. It is important that the contacts are dry, otherwise correct measurements will not be possible. Some models also have a function for measuring air humidity. Main areas of application: warehouses, hardware stores, woodworking enterprises and construction sites.

A needle hygrometer has two pointed pins that either rest against the material or are completely immersed in it. The depth of moisture measurement is equal to the length of the needle. Depending on the moisture content in the material, the electrical resistance between the needles changes - data about this is sent to the processor, which converts the signal and sends the results to the display. The needle hygrometer has very high measurement accuracy.

An induction hygrometer can have a set of metal sensors or a single spherical sensor. The measuring principle is the same for both modifications - the contact part is applied to the surface, which changes the capacitance of the sensor. The device can take measurements at depths of up to 3 - 5 cm without damaging the material. However, an induction-type device is inferior to a needle hygrometer in accuracy.

Measuring range

In air hygrometers, the measurement range is from 0 to 100%. To check the moisture content of materials, a device with upper value up to 50 - 65%. One device may indicate several measurement ranges for different materials, for example, for wood it will be from 0 to 50%, and for building materials such as concrete and brick - from 0 to 35%.

Accuracy

All humidity measuring instruments operate with an acceptable margin of error: the smaller its value, the more accurate the data. For example, an error of 2 - 3% is not so critical for models household use- such deviations do not entail serious consequences. In the control and measurement field, accurate data is needed, so it is better to choose hygrometers with an error of no more than 1%. In order to avoid the occurrence of large errors during measurements, it is necessary to observe temperature regime operation of the device as specified by the manufacturer.

Extra options

Most hygrometers are capable of measuring temperature. This is especially important for devices that help maintain a comfortable indoor microclimate. Such devices are called thermohygrometers.

Another function of the devices is to determine the dew point. It is needed when analyzing the condensate level.

Time and date displays are available for stationary air meters and digital weather stations. The most advanced models display a histogram of temperature changes over the last 12 or 24 hours.

Help article based on expert opinion author.

Hygrometer (from Hygro... and...meter)

a device for measuring air humidity (See Air humidity). There are several types of G., the action of which is based on different principles: weight, hair, film, etc.

Gravity (absolute) gas consists of a system of U-shaped tubes filled with a hygroscopic substance capable of absorbing moisture from the air. A certain amount of air is drawn through this system by a pump, the humidity of which is determined. Knowing the mass of the system before and after measurement, as well as the volume of air passed through, find absolute humidity.

The action of hair gamma is based on the property of defatted human hair to change its length when air humidity changes, which makes it possible to measure relative humidity from 30 to 100%. Hair 1 ( rice. 1 ) pulled over metal frame 2 . The change in hair length is transmitted to the arrow 3 , moving along the scale. Film humidity has a sensitive element made of an organic film, which expands when humidity increases and contracts when humidity decreases. Changing the position of the center of the film membrane 1 ( rice. 2 ) is transmitted to the arrow 2 . Hair and film g. in winter time are the main instruments for measuring air humidity. The readings of hair and film humidity are periodically compared with the readings of a more accurate instrument, the Psychrometer, which is also used to measure air humidity.

In electrolytic hydrolysis, a plate of electrical insulating material (glass, polystyrene) is covered with a hygroscopic layer of electrolyte—lithium chloride—with a binder material. When air humidity changes, the concentration of the electrolyte changes, and therefore its resistance; The disadvantage of this G. is the dependence of the readings on temperature.

The action of ceramic ceramics is based on the dependence of the electrical resistance of solid and porous ceramic mass (a mixture of clay, silicon, kaolin, and some metal oxides) on air humidity.

Condensation gas determines the dew point (see Dew point) by the temperature of a cooled metal mirror at the moment traces of water (or ice) condensing from the surrounding air appear on it. Condensation glass consists of a device for cooling a mirror, optical or electrical device, which records the moment of condensation, and a thermometer that measures the temperature of the mirror. In modern condensation thermometers, a semiconductor element is used to cool the mirror, the operating principle of which is based on the Peltier effect, and the temperature of the mirror is measured by a wire resistance or semiconductor microthermometer built into it.

Heated electrolytic hydroelectric generators, whose operation is based on the principle of measuring the dew point above the saturated temperature, are becoming increasingly widespread. saline solution(usually lithium chloride), which for a given salt is in a known dependence on humidity. The sensitive element consists of a resistance thermometer, the body of which is covered with a fiberglass stocking soaked in a solution of lithium chloride, and two platinum wire electrodes wound over the stocking, to which an alternating voltage is applied.

Lit.: Sternzat M. S., Meteorological instruments and observations, L., 1968, ch. 4; Usoltsev V. A., Measuring air humidity, Leningrad, 1959.

S.I. Nepomnyashchy.


Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

Synonyms:

See what a “Hygrometer” is in other dictionaries:

    Hygrometer... Spelling dictionary-reference book

    hygrometer- a, m. hygromètre m., German. Hydrometer lat. hydrometrum. G. or igromometer, igroskop Yan. 1 585. The gamometer is made of a hemp rope... tied at one end to a hook... and suspended through a pulley.. Wolf Phys. (Crowbar) // Sl. 18 2 68.… … Historical Dictionary of Gallicisms of the Russian Language

    - (by this, see previous page). A device for determining the degree of air humidity. Dictionary foreign words, included in the Russian language. Chudinov A.N., 1910. HYGROMETER Greek; etymology see previous. words. Device for determining the degree of humidity... ... Dictionary of foreign words of the Russian language

    - (Hygrometer) a device used to measure relative air humidity. The most common, so-called. hair g. is based on the property of hair to shorten when the relative humidity of the air decreases. Samoilov K.I. Marine dictionary. M... Marine Dictionary

    - (from hygro... and... meter) a device for determining air humidity. The most common are the psychrometer and hair hygrometer, which measures the relative humidity of the air by changing the length of a defatted human hair depending on the humidity... Big Encyclopedic Dictionary

    hygrometer- A device for determining absolute or relative air humidity [Terminological dictionary for construction in 12 languages ​​(VNIIIS Gosstroy USSR)] hygrometer Nrk. humidity meter gas moisture meter Measuring device, intended for... ... Technical Translator's Guide

    HYGROMETER, a device for measuring the content of water vapor in the air, or HUMIDITY of the atmosphere. Basic type of psychrometer. He compares the temperatures of a dry and a wet thermometer (the bulb of which is covered with a cloth moistened with water from a small... ... Scientific and technical encyclopedic dictionary

    HYGROMETER, hygrometer, male (from the Greek hygros wet and metreo I measure) (physical). A device that measures air humidity. Dictionary Ushakova. D.N. Ushakov. 1935 1940 … Ushakov's Explanatory Dictionary

    Or hygroscope for men, Greek. psychrometer; a projectile showing the degree of dampness and air humidity; moisture meter Hygrometry for women, physical the science of measuring air humidity. Hygrometric, related to hygrometry. Hygrometric substance, easy... ... Dahl's Explanatory Dictionary

    Noun, number of synonyms: 9 moisture meter (5) moisture meter (2) hygrobarometer (1) ... Synonym dictionary

    Hygrometer- – a device for determining absolute or relative air humidity. [Terminological dictionary of construction in 12 languages ​​(VNIIIS Gosstroy USSR)] Term heading: Devices Encyclopedia headings: Abrasive equipment, Abrasives, ... ... Encyclopedia of terms, definitions and explanations of building materials

This article will introduce you to the instructions (operating manual) for psychrometric hygrometers of the VIT-1 and VIT-2 types, as well as about methods for disposing of psychrometric hygrometers.

Don’t forget that you can buy psychrometric hygrometers VIT-1 and VIT-2 from us at the best price.

Instructions (manual) for the operation of psychrometric hygrometers VIT-1 and VIT-2

Introduction
1. The instructions define safety measures when working with a hygrometer, preparing it for work and operating procedures, characteristic malfunctions And Maintenance hygrometer.
2. Specifications hygrometer, amendments to hygrometer thermometers, manufacturer's guarantees are given in the passport.

Indication of safety measures when working with a hygrometer

1. When working with a hygrometer, it is prohibited:

    Subject the hygrometer to sharp shocks both during installation and during operation;

    Wipe the thermometer scale and psychrometric table with solvents, acids and other similar liquids;

    Overheat the thermometers of the VIT-1 hygrometer more than 45°C and the VIT-2 hygrometer more than 60°C. If overheated, the thermometer tanks will be destroyed.

2. When thermometers are destroyed, the thermometric liquid toluene is removed from surrounding objects hot water. Toluene is toxic, flammable, flash point is about 5°C.

Design and principle of operation of a hygrometer

1. A hygrometer is a device assembled on a base made of phenolic plastic or other materials with similar properties. Two thermometers with a scale, a psychrometric table, and a glass or plastic feeder filled with distilled water are attached to the base.The thermometer reservoir under the inscription "Humid." moistened with water from the feeder using a cambric or chiffon wick.
2. The method of measuring relative humidity with a psychrometric hygrometer is based on the relationship between air humidity and the psychrometric difference - the difference in the readings of the “dry” and “wet” thermometers, which are in thermodynamic equilibrium with the environment.By taking the thermometer readings and introducing corrections to their readings, the difference in thermometer readings is determined. Then, based on the readings of the “dry” thermometer and the difference in the readings of the “dry” and “moistened” thermometers, the relative air humidity is determined using a psychrometric table.

Preparing the hygrometer for use

1. Unpack the hygrometer and make sure that the device is complete in accordance with the passport.
2. Remove the feeder from the base. Fill the feeder with distilled water. Filling is done by immersing the feeder in a vessel with water, sealed end down.
3. Place the feeder on the base so that there is a distance of at least 20 mm from the edge of the open end of the feeder to the thermometer reservoir, and the wick does not touch the walls of the open end of the feeder.
Attention! Before installing the feeder in working position Moisten the wick by dipping the wet bulb reservoir into the water feeder.
4. Place the hygrometer in a vertical position at eye level of the person working with it. The location where the hygrometer is installed must be free of vibrations and sources of heat or cold that would create a temperature difference between the lower, main reservoir and the upper reserve reservoir of more than 2°C.
5. The psychrometric table established on the base of the hygrometer is valid for a certain vertical speed air flow(aspiration rate) washing the hygrometer. The aspiration rate is indicated in the table. You can see the full psychrometric table for the VIT-2 hygrometer at the link.
6. Before measuring relative humidity, measure the aspiration rate directly under the hygrometer. Measure the aspiration rate using a vane anemometer U5 GOST 6376-74. It is possible to use the previously produced anemometer ASO-3, type B, GOST 6376-52. The measurement procedure is in accordance with the anemometer data sheet. The aspiration rate measured by an anemometer is rounded to tenths of m/s according to the arithmetic rounding rule. You can buy a VIT hygrometer aspiration device by clicking on.
7. Measure relative humidity with a hygrometer only after establishing the readings of the hygrometer thermometers. The minimum exposure time of the hygrometer in the measured environment is 30 minutes.

Operating procedure of a psychrometric hygrometer

1. Take readings from the “dry” and “wet” thermometers. When taking readings, the worker’s eye should be at the level of the horizontal tangent to the meniscus of the liquid so that the scale mark at the reference point is visible as a straight line.
2. The person working with the hygrometer must be at a distance from it where the scale marks are normally visible and be careful not to breathe on the thermometers during readings. When reading thermometers, tenths of a degree are first quickly counted, then whole degrees.
3. Determine the temperature using thermometers with an accuracy of 0.1 ° C, introducing corrections to the thermometers given in the hygrometer data sheet to the readings. Calculate the temperature difference between the “dry” and “wet” thermometers. Corrections are introduced by algebraic addition.
4. If there are no corrections in the passport for the readings made from the “dry” and “wet” thermometers, calculate the corrections by linear interpolation using two corrections related to the temperatures between which the reading from the thermometers lies.
5. Determine the relative humidity using the psychrometric table. The desired relative humidity will be at the intersection of the lines of temperature according to the “dry” thermometer and the temperature difference between the “dry” and “wet” thermometers.
6. If the table does not contain the resulting temperature difference between the “dry” and “wet” thermometers, use interpolation to determine humidity.If there is no dry-bulb temperature in the table, to determine humidity, use interpolation only for those areas of the psychrometric table in which a change in dry-bulb temperature of 1°C gives a change in relative humidity of more than 1%.
For the remaining areas of the table, round the dry-bulb temperature values ​​to the nearest table value using the arithmetic rounding rule.

An example of determining relative humidity by interpolation

1. Determine the temperatures using the “dry” and “wet” thermometers and the difference between these temperatures.

We accept Tc = 22.4°C, the temperature difference (Tc-Tv) is equal to: 22.4-16.3 = 6.1°C.

2. Determine the relative humidity for Тс=22.4°С and Тс-Тв=6.0°С, for this purpose by interpolating the relative humidity value according to the table for Тс from 22 to 23°С and Тс-Тв=6.0°С .

With an increase in Tg by 1°C, the relative humidity increases by 2%, therefore, an increase in Tg by 0.4°C will increase the relative humidity by (0.4x2)/1=0.8%.
For Тс=22.4°С and Тс-Тв=6.0°С, relative humidity is equal to: 48+0.8=48.8%. We accept "Fp" = 4.9%.
3. We determine the relative humidity for Тс-22.4°С and Тс-Тв=6.5°С, for which we interpolate the relative humidity values ​​according to the table for Тс from 22 to 23 and Тс-Тв=6.5°С.

For Тс=22.4° and Тс-Тв=6.5°С, the relative humidity, according to a calculation similar to point 2, is 44.8%. We accept "Fp" = 45%.
4. We determine the relative humidity for Тс=22.4°С and Тс-Тв=6.1°С, for which we interpolate the found values ​​of relative humidity for Тс-Тв from 6.0°С to 6.5°С at Тс= 22.4°C.

With an increase in Tc-Tv by 0.5°C, the relative humidity decreases by 4.0%, so an increase in Tc-Tv by 0.1°C will reduce the relative humidity by (0.1x4.0)/0.5= 0.8 %.49.0-0.8=48.2%. We accept "Fp" = 48%.

Typical malfunctions of psychrometric hygrometers and methods for their elimination

1. The design of the hygrometer includes parts made of glass, so protect the hygrometer from falls and sharp impacts.
2. If the feeder is destroyed, replace it with another one included in the hygrometer kit. To do this, remove the remains of the broken one and insert a new one, securing the feeder with a spring located on the back side of the hygrometer base. Either.
3. Thermometric fluid breaks are a repairable fault. If liquid ruptures occur in thermometers, repair them by carefully heating the thermometer reservoirs to the appropriate temperatures (V IT-1 no more than 45°C and hygrometer VIT-2 no more than 60°C. If overheated, the thermometer tanks will be destroyed.)

Maintenance of psychrometric hygrometers

1. The feeder must always be filled with distilled water in accordance with GOST 6709-72. Replenish the water in advance, preferably immediately after taking measurements or at least 30 minutes before starting humidity measurements.
2. Allow the use of boiled water, boiling time for at least 15 minutes. Fill the feeder with water pre-cooled to ambient temperature.
3. The wick on the reservoir of the “wet” thermometer should always be clean, soft and moist. If the dust level in the air is up to 5 mg/m³, change the wick once every two weeks, with higher dust levels as the wick gets dirty.
4. Before replacing, remove any dirty wick from the thermometer reservoir. Wipe the reservoir with a cotton swab moistened with warm water.
5. Take the wick from the hygrometer kit or cut the wick 60 mm long, if the wicks in the kit are given in the form of a blank, for 10 pieces. Moisten the wick in distilled or boiled water and pull it onto the thermometer reservoir so that you can tie it with a thread over the reservoir. The end of the tied wick above the tank must be at least 7 mm.
6. Prepare two loops of thread. Using one loop, pull the wick tightly over the thermometer reservoir and tie the threads. Place the second loop on the wick under the tank and gradually tighten it, all the time straightening the wick so that it fits tightly around the tank. Do not tighten the loop tightly, but so that it does not interfere with capillary wetting of the wick fabric on the thermometer reservoir.
7. To make a new wick, use cotton chiffon, bleached, undyed, technical without prohibition according to GOST 9310-75 or bleached cambric, mercerized, article 1402 NA according to GOST 8474-80. It is allowed to use cotton stocking cord, art. 494, OST 17-184-75.
8. Before making the wick, treat other types of chiffon or cambric as follows:

  • wash in hot water (10 g of soda per 1 liter of water),
  • boil in a solution of the same concentration for 1.5-2 hours,
  • rinse in hot water, change the water until it is clean,
  • dry and iron.

9. Sew the wick along the diameter of the thermometer reservoir using a simple machine seam. After trimming, the height of the seam should be no more than 1.5 mm.
10. Install the new wick and feeder on the hygrometer in accordance with the instructions.
11. The hygrometer is subject to initial and periodic verification. Primary verification is carried out upon release from production, periodic verification- once every two years in accordance with methodological instructions MI-737-83 "Psychrometric hygrometer type VIT. Methods and means of verification", approved by in the prescribed manner. Information about the verification of the hygrometer is given in the passport.

Rules for storing and transporting hygrometers

1. Store hygrometers in closed, dry rooms in a vertical or inclined position, in accordance with the inscription “Top” on the box, at a temperature from -60°C to +45°C. Do not store hygrometers less than 1 m from heat sources ( heating devices, various heaters, etc.).
2. Hygrometers in transport containers are transported by any type of transport, taking into account the temperature indicated above and subject to compliance with the rules for the transportation of goods for the corresponding type of transport.

Disposal of psychrometric hygrometers

Unlike mercury devices, recycling hygrometers is quite simpler: you just need to throw them away. On this moment There is no law that states that hygrometers must be disposed of in a special way.

If the hygrometer has expired, then there is no point in re-verifying it; it is much cheaper and more profitable to purchase it from us at affordable prices.

A hygrometer is an instrument used to measure the humidity in the atmosphere, indoors, or other enclosed space. How to use a hygrometer? It usually does not measure humidity itself, but determines indirect changes in the properties of a substance when absorbing moisture, on the basis of which the humidity indicator is determined through calculations.

Modern electronic devices use condensation temperature (dew point). Normal use The purpose of a hygrometer is to monitor weather conditions and obtain information to make a weather forecast. Combined with temperature, barometric pressure and wind speed data, humidity tells a lot about the weather ahead. For example, low Atmosphere pressure, associated with low temperatures and high humidity levels, indicates that rain is coming soon. A person needs such data so that he can comfortably organize his affairs.

Humidity is more difficult to measure than temperature, which is why the first hygrometers were not entirely accurate. Leonardo da Vinci invented the first version of the hygrometer already at the end of 1400. Guillaume Amontons invented the hygrometer, which was similar to a three-fluid barometer, in 1687. In 1781, Horace Benedict de Saussure (1740-1799) discovered that human hair is a good indicator of moisture. A major breakthrough in hygrometry was made in 1802 by British explorer John Dalton (1766-1844). He showed that the amount of water vapor required for saturation depends strongly on temperature. This led to an understanding of relative humidity and how to use a psychrometric hygrometer.

The moisture meter readings are interchangeable, simple calculations they are converted from one type to another - relative humidity helps determine the dew point or absolute humidity.

In order to learn how to use a hygrometer, you need to consider the main types of devices for measuring humidity. The psychrometer consists of two separate thermometers mounted on one body. One is dry and the other is wet (wet). The lower end of the wet thermometer is covered with a special cloth that acts as a wick. It is constantly in the water, cooling and wetting the wet bulb. At temperatures (T) above the freezing point of water, the wick reduces the wet-bulb temperature, which is usually lower than the dry-bulb temperature. However, when the air temperature drops below zero, the wet bulb becomes covered thin layer ice, and it may be warmer than a dry bulb.

Relative humidity is calculated based on the ambient temperature, dry bulb temperature, and the temperature difference between the dry and wet bulb temperatures. Relative humidity is determined using a psychrometric chart. When two temperatures are equal, the air is completely saturated, and the greater their difference, the drier the air. Using special tables, knowing the T air and the psychrometric difference (T - T m), the remaining air parameters are determined. Psychrometers are commonly used in meteorology and in residential and residential HVAC systems. public buildings.

Electronic mirror dew point hydrometer

The dew point is the temperature at which a sample of moist air (or any other water vapor) at constant pressure reaches water vapor saturation. At this saturation temperature, further cooling causes water to condense. How to use electronic hygrometer? Electronic mirror dew point hydrometers are among the most accurate instruments available today. They use a cooled mirror and an optoelectronic mechanism to detect microcondensation on the mirror surface.

The mirror temperature is controlled electronically feedback to maintain dynamic equilibrium between evaporation and condensation, thereby carefully measuring the dew point temperature. These devices require frequent cleaning, a trained operator, and periodic calibration to achieve a high level of accuracy. More recently, spectroscopic cooled mirrors have been introduced. In them, the dew point is determined using spectroscopic analysis, specifying the nature of condensation. Their main advantage is that they operate at temperatures down to -70°C.

Indoor hygrometer: types and functions of the device

The psychrometric method is used to change air humidity in residential, public and industrial buildings. How to use a psychrometric hygrometer? The device consists of two thermometers. The end of one of the thermometers, in the psychrometric body on the right, is wrapped with the end of a small cloth - a wick (medical bandage) in several layers, and the second is lowered into a container with clean water. The glass is closed with a special lid, which has a hole for the wick. The wet bulb temperature begins to drop as heat is absorbed; the equilibrium point between evaporation and the decrease in wet bulb temperature occurs after approximately 30 minutes.

A dry bulb measures the temperature of the indoor air in a room, while a wet bulb measures the temperature of the indoor air. How to use a psychometric hygrometer is described in detail in the instructions that come with the device. The panel contains psychrometric tables for determining air humidity. Removal is carried out by an employee without delay, since a long stay near the device can change the readings and distort the result of measuring humidity. For the most accurate result, the device must be installed so that the operator’s eyes are located at the level of the meniscus of the thermometers.

The most common indoor psychrometers are the thermometer-hygrometer VIT-1 and VIT-2. Structurally, they are very similar, but have significant differences in the field of application, so VIT-1 is used when the air temperature in the room is from 0°C to +25°C, and VIT-2 is from +15°C to +40°C.

An example of determining air humidity with a psychrometer:

  • Dry bulb temperature: +23.0°C;
  • wet: +20.5°C;
  • temperature difference: +2.5°C;
  • Using the psychrometric table on the panel, we determine the relative humidity: 77%.

This indicator of relative humidity is unacceptable, since GOST 30494-96 “Indoor microclimate parameters” establishes the following humidity standards:

  • Winter/autumn - 30-45%;
  • spring/summer - 30-60%.

Ways to reduce indoor humidity:

  1. In winter. Ventilate the apartment. It is better if there is a possibility through supply ventilation warm air.
  2. Use a dehumidifier.
  3. Find possible leaks in water supply networks.
  4. Use air conditioning in heating mode.
  5. Turn on the kitchen hood.

Hygrometer VIT-1

VIT-1 measures humidity in rooms where the air condition is strictly controlled: on poultry farms, in libraries, in educational and medical institutions, if the internal air temperature does not exceed +25°C. How to use a hygrometer? VIT-1 is used at humidity from 20 to 90%, T from 5°C to +25°C. The VIT-1 wet thermometer is filled with toluene, and the wick is moistened with clean or rain water. The dimensions of the device are 290 mm x 120 mm x 50 mm. The device is inspected by government authorities every two years.

Hygrometer VIT-2

The design of VIT-2 is practically no different from VIT-1. The plastic case contains thermometers, a feeder and a table for calculations. How to use the VIT 2 hygrometer? The principle of operation is no different from VIT-1, but their psychrometric tables are different, therefore the calculations for humidity also differ.

First, the dry T is determined, then the wet T, and the required value is determined from the delta T at the intersection point of the “dry” thermometer using the psychrometric table. Speed air environment should be no more than 2 m/s so as not to distort the measurements.

The KTJ-TA218A moisture meter is suitable for measuring indoor humidity and temperature levels. How to use the TA218a hygrometer? A thermohygrometer or digital thermohygrometer is electronic device, which measures and displays temperature (T) and relative humidity (RH). Applications: ventilation and air conditioning, climate control, hospitals, food factories, saunas, GYM's, offices, conference rooms, museums, libraries, archives, computer rooms, printing, warehouse or home automation.

Device characteristics:

  • measurement range external temperature: 0°C - 50°C.
  • Display indication: C/F.
  • Humidity measurement range: 10-95% RH.
  • Temperature measurement accuracy: +/- 1°C.
  • Humidity measurement accuracy: +/- 5%.
  • cable length: ~ 2 m.
  • supply voltage: 1.5 V direct current AAA.
  • Display: 3.8 inches.

Moisture meter MODEL C-02

The device measures CO2, T and humidity, with a triple LCD display. How to use a hygrometer? MODEL C-02 T wet bulb thermometer and dew point function. Dual band infrared CO2 sensor.

The device performs:

  • Automatic measurement log keeping with data transfer to a PC. Data Hold: Freezes the display.
  • Low battery indicator.
  • Operating temperature: 5°C to 50°C.
  • Operating humidity: -10 to 90% humidity.
  • Storage humidity: 10 to 90% relative humidity.
  • Accuracy: CO2: ±3% or ±50ppm,
  • Humidity: ±5% RH,
  • Temperature: ±1 C, ±1.8 F.
  • Automatic memory capacity: 20,000 measurements.
  • Serial interface RS-232.

GAOTek Mini Temperature and Humidity Hydrometer

The GAOTek Mini Hygrometer is designed with an integrated measurement function over a wet bulb temperature range of 0°C to 80°C. How to use a hygrometer correctly? The integrated measurement function is ambient temperature, humidity, dew point and wet bulb temperature. This is a digital T meter with high accuracy and low power consumption. It is equipped with humidity sensors and an industrial-grade digital display. It is suitable for measuring T and humidity in any industrial sector, in workshops, factory warehouses, libraries, offices, laboratories, etc.

Model features:

  • high productivity and accuracy;
  • fast reaction time;
  • control of dry and wet thermometers;
  • microprocessor design;
  • sleep mode;
  • screen hold;
  • backlight function;
  • low power consumption;
  • digital screen;
  • dew point temperature;
  • temperature range from -30°C to +100°C;
  • Humidity range 0% to 100% rh;
  • dew point temperature from -30°C to +100°C;
  • wet bulb temperature 0°C to 80°C;
  • humidity accuracy 2% rh (from 20% to 80% at + 25°C);
  • response time 10 seconds (90% T+25°C).

Hydrometer Testo 645

Dual-channel measurement of T and humidity. Very accurate humidity measurement up to ± 1% rF s internal memory measurements. How to use a hygrometer? Testo 645 displays the following values ​​at the touch of a button: humidity, dew point, enthalpy and temperature. Convenient evaluation of measurement data with transfer to a PC and indicating the measurement location. Maximum humidity 100%. Minimum humidity 0%. Temperature from -50°C to +150°C.

5 reasons why you need to regularly measure indoor moisture

You need to learn how to properly use a psychrometric hygrometer in order to regularly measure the humidity in environment, since it seriously affects human life.

  1. Comfort at home. People spend much more time at home than outside, so measuring the humidity at home is very important to create a comfortable living environment. After all, only by determining the moisture content in the air can you decide whether you need to turn on the heating or ventilation system. Humidity directly affects the comfort in the apartment, and it is recommended to maintain its value in the range from 25 to 55% or, even better, from 40 to 50%. Humidifiers and dehumidifiers can be used to ensure that home occupants always feel great, no matter what the weather is like outside.
  2. Health protection. Inadequate humidity levels pose potential health risks. If the humidity in the home is too high, there is a risk of mold and bacteria growing, some of which are extremely dangerous, especially when children live in the home. Excessively dry air is another problematic factor and can cause itchy skin, coughing, and other painful symptoms. Dry air is a breeding ground for allergens. By measuring humidity, you can achieve optimal air parameters to ensure healthy image life.
  3. Security of property. Too much moisture in the air and the house will become filled with mold and mildew. Warm and wet air- the perfect recipe for mold, which will grow everywhere: in the shower, kitchen, food, furniture and books. Once you determine that the humidity is high, you will need to thoroughly ventilate the house and dry the air with an air conditioner or dehumidifier. A moisture testing tool can help monitor humidity. Dry air can cause damage musical instruments or furniture, as the wood may crack and warp. You can save a lot of money on expensive repairs or replacement of furniture if you control the humidity in a timely manner.
  4. Animal protection. Humidity can be detrimental to pets, sometimes even more so than to humans; humidity must be carefully controlled to keep animals comfortable.
  5. Harvest safety. Without a reliable hygrometer, it is impossible to grow crops in a greenhouse or conservatory, where it is necessary to maintain specific plant parameters. Too much moisture and you'll have to deal with root rot, fungi and a host of other problems that are best avoided by keeping the humidity at the right level.