Last winter I understood with air humidity and humidifiers. By the spring, the captain still managed to convey to me the need to measure humidity, if I was going to regulate it. One hygrometer, I, however, was long before that. There was no understanding whether he shows the humidity in the house or at the top of Kilimanjaro. I chose and ordered two more two more. Choose with different sensors. Semi-annual general positive experience - under the cut.
My first hygrometer is a DHT11 sensor attached to WiFi Itead Sonoff Th. His, today we are talking about others. The DHT11 sensor does not use the fame of accurate. But, looking at the moisture numbers in winter in the area of \u200b\u200b18%, I still wondered - well, can not be so much! I decided to choose a pair of hygrometers with different sensors and compare. The idea with a psychrometer from dry and wet thermometers left for an extreme case as too gimorous.
Red, according to the seller
Measurement range: Temperature-50C- + 70C (-58F- + 158F) Humidity 10% -99% relative humidity
Measurement accuracy: temperature ± 1C (± 2F) humidity ± 5% relative humidity
Display Resolution: Temperature 0.1C (0.2F) Humidity 1% relative humidity
Operating voltage: 1.5 V, two buttons Size LR44 cell (not included)
Dimensions (d * sh * d): 6 x 4.8 x 1.5 cm / 2.36 "x1. 89" x 0.59 "(approximately)
LCD size: 3.5 x 1.6 cm / 1.38 "x 0.63" (approximately)
According to my measurements
In both, planting size 45 x 25
Dimensions, white without taking into account wires 48 x 29 x 17
Dimensions, red 61 x 57 x 17
White, sensor
The length of the actual wire, without taking into account the sensor - 150 cm
landing diameter of the sensor ⌀ 9.2 mm,
Length of the planting cylinder 36 mm
Dimensions ⌀14 x 61
Mechanical (psychoometric) hygrometer - very sensitive to shaking, sharp temperature differences and vibration instrument. Under the action of these factors, the accuracy of its testimony can significantly decrease. Even if the device initially showed the correct level of humidity, during the transportation or movement of the hygrometer to the room with other conditions, as well as before buying in the store, Excee CJSC recommends that the device is re-tested. Checking the device on the correctness of the readings is called calibration.
In order to correct the instrument readings, in the case of most models there is a special mechanism in the form of a screw. When it rotates the position of the arrow will change. If there is no such mechanism (which is often in cheap models), the device must be fully disassembled.
H2: Calibration Methods
In order to achieve accuracy of indications, it is necessary to place the device on Wednesday with a pre-known air humidity. If the hygrometer will correctly display the microclumatic conditions, it is not necessary to calibrate it. There are three methods that are used most often:
It is worth noting that the actions described are carried out only with mechanical measuring devices. Electronic hygrometers are not required to calibrate, since their accuracy does not change over time.
The hygrometer is a tool used to measure humidity in the atmosphere, indoors or in another closed space. How to use a hygrometer? It is usually measured not the humidity itself, but determines the indirect changes in the properties of the substance at the absorption of moisture, on the basis of which, by calculations, the humidity indicator is determined.
Modern electronic devices use condensation temperature (dew point). The usual use of a hygrometer is to monitor weather conditions and receiving information to prepare weather forecast. In combination with temperature data, barometric pressure and wind speed, humidity speaks a lot about the upcoming weather. For example, low atmosphere pressureassociated with low temperature and high humidity levels, suggests that the shower will soon go. Man Such data is needed so that it can comfortably organize his affairs.
Humidity is harder to measure than the temperature, and therefore the first hygrometers were not entirely accurate. Leonardo da Vinci invented the first version of the hygrometer at the end of 1400. Guide Amononts invented a hygrometer, which was similar to a three-sided barometer, in 1687. In 1781, Horace Benedict de Sosurur (1740-1799) discovered that human hair shows well the humidity. A major breakthrough in the hygrometry was made in 1802 by the British researcher John Dalton (1766-1844). It showed that the number of water vapors required for saturation is highly dependent on temperature. This led to an understanding of relative humidity and how to use hygrometer psychrometric.
The indications of the moisture makers are interchangeable, by simple calculations they are converted from one species to another - relative humidity helps to determine the dew point or absolute humidity.
In order to learn how to use a hygrometer to consider the main types of instruments for measuring humidity. The psychrometer consists of two separate thermometers fixed on one case. One is dry, and the other is wet (wet). The lower end of the wet thermometer is covered with a special cloth performing the role of wick. It is constantly in water, cooling and wetting the wet thermometer. At temperatures (T) above the water freezing point, the phytile reduces the temperature of the wet thermometer, it is usually below the dry. However, when the air drops below zero, the wet thermometer is covered with a thin layer of ice, and it can be the warmer of a dry thermometer.
Relative humidity is calculated on the basis of the ambient temperatures, the dry thermometer and the temperature difference, between the indicators of dry and wet thermometers. Relative humidity is determined by a psychrometric card. When two temperatures are equal - the air is completely saturated, and the more their difference, the land. According to special tables, knowing the air and the psychrometric difference (T - T M), the remaining air parameters determine. Psychrometers are usually used in meteorology, as well as in heating, ventilation and air conditioning systems of residential and public buildings.
The dew point is a temperature at which a sample of wet air (or any other water vapor) at constant pressure reaches the saturation of water vapor. At this saturation temperature, further cooling leads to water condensation. How to use an electronic hygrometer? Electronic mirrored dew point hydrometers are today one of the most accurate instruments. They use chilled mirror and optoelectronic mechanism to detect microcondensation on the surface of the mirror.
The mirror temperature is controlled by electronic feedback to maintain a dynamic equilibrium between evaporation and condensation, thereby thoroughly measuring the temperature of the dew point. These devices need frequent cleaning, qualified operator and periodic calibration to achieve high level accuracy. Most recently, spectroscopic chilled mirrors were introduced. In them, the dew point is determined using spectroscopic analysis, specifying the nature of condensation. Their main advantage is that they work at T to -70 ° C.
The psychrometric method is used when changing air humidity in residential, public and industrial buildings. How to use hygrometer psychrometric? The device consists of two thermometers. The end of one of the thermometers, in a psychrometric building on the right, is wounded by the end of a small fabric - the phytyl (medical band) in several layers, and the second is descended into the container with clean water. The glass is closed by a special lid, which has a wick hole. A wet thermometer begins to fall the temperature with heat absorption, the equilibrium point between evaporation and a decrease in the temperature of the wet thermometer occurs by about 30 minutes.
A dry thermometer determines the temperature of the indoor indoor, and the wet is a wet thermometer. A psychometric hygrometer is described in detail in the instructions that are included in the instrument. The panel contains psychrometric tables to determine air humidity. Removal is carried out by an employee without delay, since long-ending near the instrument can change the indicators and distort the result of measuring humidity. For the maximum accurate result, the device must be installed so that the operator's eyes are located at the level of the thermometers.
The most common psychrometers for premises are the thermometer-hygrometer WIT-1 and WIT-2. Structurally, they are very similar, but have significant differences in the application, so VIT-1 is used when the air temperatures in the room from 0 ° C to + 25 ° C, and WIT-2 - from + 15 ° C to + 40 ° C.
An example of determining air humidity by a psychrometer:
This indicator of relative humidity is unacceptable, since GOST 30494-96 "Parameters of the indoor microclimate" sets are set by the following humidity standards:
Ways to lower moisture in the room:
WIT-1 measures humidity in rooms where the air condition is strictly conducted: on poultry farms, in libraries, in educational and therapeutic institutions, if t internal air does not exceed + 25 ° C. How to use a hygrometer? WIT-1 is used with humidity from 20 to 90%, t from 5 ° C to + 25 ° C. The wet thermometer WIT-1 is filled with toluene, and the wick is wetted with clean or rain water. Dimensions of the device 290 mm x 120 mm x 50 mm. The device is checked by government agencies every two years.
The design of WIT-2 is practically no different from WIT-1. The plastic case has thermometers, feeder and table for calculations. How to use a hygrometer WIT 2? The principle of operation is not different from WIT-1, but they have different psychrometric tables, therefore, the calculations on humidity will also differ.
At first, the T is determined, then T is wet, on the delta T at the point of intersection of the "dry" thermometer in a psychrometric table set the desired indicator. Speed aerial There must be no more than 2 m / s to not distort the measurements.
KTJ-TA218A moisture meter is suitable for measuring the level of humidity and temperature in the rooms. How to use a hygrometer ta218a? The thermohygrometer or digital thermohygrometer is an electronic device that measures and displays the temperature (T) and relative humidity (RH). Apply: ventilation and air conditioning, climate control, hospitals, food enterprises, saunas, gyms, offices, conference rooms, museums, libraries, archives, computer rooms, printing, warehouse or home automation.
Device characteristic:
The device measures CO2, t and humidity, with a triple liquid crystal display. How to use a hygrometer? Model C-02 T wet thermometer and dew point function. Dual-band infrared CO2 sensor.
The device performs:
The Gaotek MINI hygrometer is designed with an integrated measurement function in the temperature range of a wet thermometer from 0 ° C to 80 ° C. Hygrometer how to use? Integrated measuring function is the environment, humidity, dew points and a wet thermometer. This is a digital meter t with high accuracy and low power consumed. It is equipped with humidity sensors and a digital industrial display. It is suitable for measuring T and humidity in any industry, in workshops, in factory warehouses, in libraries, in offices, in laboratories, etc.
Features of the model:
Two-channel dimension T and humidity. Very precise measurement of humidity up to ± 1% RF with internal measurement memory. How to use a hygrometer? Testo 645 With one touch of the button displays the indicators: Humidity, dew point, enthalpy and temperature. A convenient estimate of the measurement data with the transmission to the PC and indicating the measurement location. Maximum humidity is 100%. Minimum humidity 0%. Temperature from -50 ° C to + 150 ° C.
It is necessary to learn how to properly use hygrometr psychrometric to regularly measure moisture in the environment, since it seriously affects human vital activity.
