Homemade air humidity meter. All about the psychrometer for the incubator. Is there an alternative to an electronic device for measuring humidity in an incubator?

IN modern conditions development is very topical issue is arrangement . To create in it comfortable conditions Various measuring instruments are used. Thus, changes in temperature and humidity can be monitored using a psychrometer or hygrometer. Let us consider in detail the principle of their operation.

Principle of operation

Being an instrument for measuring humidity and temperature in a room, a psychrometer is a device on which 2 mercury columns, located independently of each other. They are called dry and wet bulb thermometers.

Did you know? First mercury thermometer was invented by the Italian doctor Santorio, born on March 19, 1561. Working in European countries, he studied the process of breathing, and conducted some of his experiments on himself. The inventor of the first practical hygrometer is Francesco Folli.

Its operating principle is based on ability of water to evaporate, provoking the occurrence of a temperature difference according to the psychrometer. The speed of this process depends on the level of humidity. The higher it is, the smaller the difference between the thermometer readings will be. This is due to the fact that during the process of evaporation of water, the container in which it is located is cooled.

Types of hygrometers

Depending on the design features, there are several types of this measuring device. Among them are weight and ceramic hygrometers, hair moisture meter, and film sensor. Let's take a closer look at the description of each of them.

This measuring device is a system consisting of U-shaped tubes that are filled with a hygroscopic substance. Its property is the ability to absorb moisture released from the air. Through this system, a certain amount of air is drawn in using a pump, after which it is determined absolute humidity. To do this, you will need to calculate indicators such as the mass of the system and the volume of air passed through.

Hair moisture meter

This device is a metal frame on which fat-free human hair is located, stretched lengthwise. It is connected to the arrow, and its free end is equipped with a light weight. Thus, depending on the degree of humidity, the hair is able to change its length, signaling this by a moving arrow.
It should be noted that intended for home use The hair moisture meter has a small error. In addition, its fragile design can quickly break under mechanical stress. To avoid this, it is recommended to hang the measuring device on the wall, and also make sure that there are no vibrations in the selected place, and that sources of cold or heat are located at a distance of at least 1 m. If the hair is dirty, it can be cleaned using a brush previously moistened with cleaned water.

Important! The best temperature conditions for the hair moisture meter to work, the range is from -30...+45 degrees. In this case, the accuracy of the device will be 1% relative humidity.

Film sensor

This device is a vertical design. It consists of an organic film, which is a sensitive element. It is capable of stretching or shrinking depending on the increase or decrease in humidity, respectively.

Ceramic

This device looks like a clock, only the numbers depicted on it are divisions of the mercury column, indicating the percentage of air humidity. The main element for its manufacture is a ceramic mass, which contains metallic impurities of kaolin, silicon, and clay. This mixture has electrical resistance, the level of which is affected by air humidity.

How to choose the right hygrometer

Before choosing a hygrometer, you need to consider that there is several types: wall-mounted, table-top, mechanical and digital. These devices differ not only in their technical characteristics, but also in their configuration and accuracy of indicators. In addition, they may have additional functions, such as calendar, clock, alarm clock, comfort level indicator, etc.

Important! If the hygrometer is placed on a tabletop, you should take into account not only its dimensions, but also the angle of rotation of the device to the light source. This will allow you to obtain more accurate data.

When studying technical parameters sensor, pay attention to the relative and absolute pressure indicators. Moreover, the choice of device should depend on the size of the incubator. So, if it is intended for more than 100 eggs, it is necessary to install a more powerful hygrometer.

Examples of the most popular models:

How to make a hygrometer yourself

An alternative to a store-bought device can be homemade hygrometer. To make it, you will need to acquire some materials and tools, as well as study step-by-step instructions.

Materials and tools

In order to construct a psychrometer yourself, you need to purchase two thermometers. In addition, you will need a piece of cloth and a small cup of distilled water.

Such a liquid can be obtained by purifying it from impurities or simply purchased in a store. Don't forget about the mounting panel. It can be made of plastic, wood or other materials.

Did you know? The largest thermometer operating in Eurasia is considered to be a device installed in 1976 in the Ukrainian city of Kharkov, with a height of 16 m.

Step-by-step manufacturing instructions

To make the fixture manually, you will need to perform the following actions:

1. Attach 2 thermometers to the panel, placing them parallel to each other.
2. A container of water should be placed under one of them.
3. The mercury reservoir of this thermometer must be wrapped in cotton cloth and attached by tying it with thread.
4. Dip the edge of the fabric into water 5-7 cm.

Thus, the thermometer on which this manipulation was carried out will be called “wet”, and the second one will be called “dry”, and the difference between their indicators will show the level of humidity.

Special moisture meters are used. Today there are needle, contact and chip modifications. In terms of parameters, they are quite different. However, there are not many manufacturers of moisture meters on the market. The main companies include, first of all, EMCO and Valcom. Costs on average good moisture meter on the market around 1500 rubles.

How to do it yourself?

If necessary, you can make a moisture meter for wood with your own hands. Its circuit includes a dielectric-type sensor. The device will also require compact generator. Its maximum frequency parameter must be no more than 30 MHz. Contacts for homemade model It is more advisable to select needle-shaped ones. Also, to make a moisture meter for wood with your own hands, you will need a three-channel type microcircuit.

The device should be in the region of 3.5 F/m. The microprocessor for the model is selected with a pulse amplifier. Probes are most often used tubular type. It is more advisable to select a lowercase display. Compared to text counterparts, it is simpler. The electrodes used in moisture meters are capacitive ones. In turn, the catcher will need to be installed resistive. Lastly, batteries are selected for the model. In this case, you can use regular AA batteries.

Contact models

Contact wood moisture meters are well suited for working with plywood and parquet. Additionally in construction industry devices are used to determine the humidity of panels. If we talk about contractual features, then low-frequency generators are used in the devices. The probes themselves are installed in a tubular type.

The dielectric constant of most moisture meters does not exceed 3 F/m. Maximum temperature models of this type are capable of holding at 40 degrees. The display is used in both line and text types. Many modifications are equipped with temperature sensors. Many devices have a calibration function. On average, a high-quality moisture meter costs around 2 thousand rubles.

Needle moisture meters

Needle moisture meters for wood are usually used for pine or spruce. Sensors in all configurations are of the dielectric type. If we talk about parameters, then the measurement accuracy generally fluctuates around 0.2%. The maximum humidity threshold for devices does not exceed 35%. Minimum permissible temperature for models is 0 degrees. Microprocessors in many devices are used with amplifiers. The average price for a wood moisture meter (needle type) is around 1,200 rubles.

Probe devices

Probe moisture meters for wood are mainly manufactured by the Valcom company. If you believe the opinion of experts, then their parameter is extremely low. Generators in devices are used with a frequency of 20 MHz. The catchers themselves are installed of the resistive type. The minimum humidity threshold for models does not exceed 5%. In turn, the devices are located at level 1 RN. Displays of moisture meters are often used in line type. Some modifications are equipped with thermometers. The calibration function in devices is quite rare. You can find a model of this type on the market for 2 thousand rubles.

Model EMCO AR

In the construction industry, the presented moisture meter is used in great demand. It is ideal for working with parquet and panels. This moisture meter is also equipped with a thermometer. Another advantage of the modification can be safely called the presence of needle-type contacts. The manufacturer provides a three-channel microcircuit for the model, so wood moisture is measured quickly. The electrodes are of the capacitive type.

The maximum humidity threshold does not exceed 40%. In terms of size, the specified moisture meter is very compact and belongs to the class portable instruments. According to the documentation, its weight without batteries is 80 g. The resolution of the model is at the level of 1.3 pH. The maximum permissible temperature of the model is exactly 35 degrees. The presented device must not be used in cold weather. The measurement accuracy fluctuates around 1.4%. In stores, this device can be found for 2100 rubles.

Devices for determining moisture EMCO MP500

This moisture meter is equipped with a dielcometric type sensor. If you believe customer reviews, the resolution of the device is quite high. The generator itself is used at 22 MHz. According to the documentation, the maximum permissible temperature is 40 degrees. The display in the device is of text type.

The batteries are 1 mAh, so they last a long time. In this case, the catcher is provided by the manufacturer as a resistive type. If you believe the reviews of experts, then problems with determining the importance of wood chips do not arise. Maximum depth measurement is 10 mm. The user can purchase the presented moisture meter for 1,400 rubles.

Model "Valkom EM4806"

This moisture meter for hardwood, among other models, is distinguished by a high resolution parameter at the level of 1.3 pH. All this suggests that the device works perfectly at temperatures below 10 degrees. In this case, the measurement accuracy indicator is at 0.2%. The maximum permissible humidity threshold is 30%.

The catcher in the device is of a resistive type. The microcircuit is a three-channel one, and the generator is installed as a low-frequency one. According to the documentation for the device, the case is equipped with an IP 62 protection system. The presented model weighs exactly 80 g. The moisture meter’s memory is enough for 30 thousand measurements. The user can buy it for 1,500 rubles.

Reviews about "Valkom M804"

This wood moisture meter mostly receives good reviews. The main advantage of the model lies in its compactness. If we talk about more design features, it is important to note that it uses probe contacts. There are two sensors directly in the housing. Thus, the measurement accuracy is quite high.

The manufacturer provides the probe in the device with a tubular type. The resolution of the device fluctuates around 1.3 pH. The maximum humidity threshold, according to the documentation for the moisture meter, is 35%. Buy today this model possible for 2 thousand rubles.

Opinion about "Valkom AS101"

The presented moisture meter is in great demand in construction safra. First of all, mention should be made of a high-quality generator, which is installed with a frequency of 33 MHz. In this case, the sensor is of a dielectric type. The contacts, in turn, are needle-shaped. If you believe the reviews of experts, the measurement accuracy of the model is high.

It can be used for parquet and panels. The minimum permissible temperature of the device is 0 degrees. The resolution indicator is 1 pH. The catcher itself in the device is installed of a resistive type. The microprocessor is used with a switching amplifier. The maximum humidity threshold of the device is at 40%. You can buy this moisture meter for only 1,400 rubles.

Description of "Ectech MO280"

This portable moisture meter features a protected housing. It uses a low-frequency sensor. In turn, the contacts are needle-shaped. The presented copy has a calibration function. Temperature environment With the help of this device you can determine. It is also important to mention the high resolution of the model.

The measurement accuracy in this case is 0.3%. The maximum humidity threshold allowed by the model is 45%. The microprocessor is provided by the manufacturer with an operational amplifier. Thus, data processing does not take much time. The memory of the presented modification is enough to make more than 20 thousand measurements. You can buy this moisture meter in a store for 1,300 rubles.

Model "Ectech MS60"

These wood moisture meters are often used professional builders. They can work even at temperatures of 0 degrees. The model uses a high-quality case protection system. If you believe consumer reviews, the device is quite simple to use. The batteries for the model are selected with a capacity of 1.2 mAh.

According to many owners, they last a long time. The probe of the presented moisture meter is of a tubular type. The microcircuit in the case is three-channel. This modification is equipped with a thermometer, and this pleases many buyers. If we talk about the parameters, then the measurement accuracy is at around 0.3%, and the resolution of the device is only 1.2 pH.

It is prohibited to operate the device at temperatures above 35 degrees. The maximum permissible humidity is 40%. These moisture meters are sold on the market at prices starting from 2 thousand rubles.

Humidity is a vital parameter for the normal development of embryos in the incubator. In the first week of laying eggs, its value should be 60–70%, in the second - no more than 40–50%, in the third it should be significantly higher - no less than 75%. This indicator can be measured special device- hygrometer.

How does a hygrometer work?

A hygrometer or moisture meter is a device that allows you to determine the level of air humidity inside the incubator. To determine this value, the device is lowered into the container through a special hole for several minutes. Some time later, indicators appear on the sensor screen. At open lid You should wait at least an hour for accurate data to appear in the incubator.

Important!Falls, dirt and straight Sun rays negatively affect the operation of the moisture meter. For normal operation of the device, it should be protected from the negative influence of the external environment.

Types of hygrometers for incubators

Moisture meters can be different types. Depending on the principle of their operation, each of them has its own characteristics, certain advantages and disadvantages.

Weight

The operation of this device is based on a system of tubes interconnected. They are filled with a hygroscopic substance that absorbs air. Absolute humidity can be calculated thanks to the difference in weight before and after passing a certain portion of air. A special formula is used for this.

The disadvantage of this device is obvious - it is quite difficult for the average user to carry out the necessary mathematical calculations every time. The advantage of a gravimetric moisture meter is the high accuracy of its measurements.

Hair

This type of device is based on the property of hair to change length with changes in humidity. To determine this indicator, the hair in the incubator container is stretched onto a special metal frame.

Did you know?You can check the serviceability of the moisture meter upon purchase by holding the device in your palm for a few seconds. Under the influence of human body heat, the sensor readings should change.

It records changes using an arrow on a special scale. The main advantage of the method is simplicity. The disadvantages are fragility and low measurement accuracy.

Film

The operating principle of this device is based on the property of an organic film to stretch when high humidity and shrink when its level decreases. The film sensor works on the principle of a hair sensor, only here changes in the elasticity of the film under the influence of a load are recorded.

The data is displayed on a special display. The pros and cons of this method are identical to the characteristics of a hair moisture meter.

Ceramic

The operation of this device is based on the dependence of the resistance of a ceramic part, which consists of clay, kaolin, silicon and oxides of some metals, on air humidity.

Important!To increase the humidity in the incubator, the eggs are sprayed with water. However, this should only be done with waterfowl eggs.

The advantages of this type of device include their ability to accurately measure humidity over a wide range; the disadvantages are their considerable cost.

How to choose a hygrometer for an incubator

When making a choice, it is important to get as much information as possible about technical specifications device. When purchasing a moisture meter, the size of the incubator is also important - the larger it is, the more powerful the device should be.

When choosing a device, it is important to consider the following characteristics:

• for models with a remote sensor, the integrity of the cable and display should not be compromised;
• the pressure parameter can be relative (RH) and absolute (g/cub. m);
• if there is a need for a high-precision device, then an optical device is ideal for this;
• To place the device outside a living space, it is best to purchase a hygrometer with a high degree of protection against external factors, this indicator is measured on the IP scale.

How to make a hygrometer with your own hands

Making this device at home is not particularly difficult. Difficulties arise when using it - it requires certain mathematical knowledge and care to avoid errors in calculations.

Tools and materials

To make a moisture meter you will need:

• two mercury thermometers;
• a board to which these thermometers will be attached;
• a small piece of fabric;
• thread;
• flask;
• distilled water.

Manufacturing process

To make a hygrometer with your own hands, you must perform the following steps:

1. Two thermometers are attached to the board parallel to each other.
2. Under one of them there is a flask with distilled water.
3. The mercury ball of one of the thermometers is carefully wrapped in cloth, which is tied with thread.
4. The edge of the fabric is lowered into the water to a depth of 5–7 mm. This way we get a “wet” thermometer.
5. The readings of both thermometers must be compared and air humidity determined using a temperature difference table.

Similar homemade device- a dubious alternative. Firstly, the readings obtained in this way have serious errors.

Secondly, to take readings you need to constantly open the lid of the incubator.
Which hygrometer will be chosen depends on the desires and capabilities of the poultry farmer. Today we bring to their attention big choice modern moisture meters: easy to use, with digital displays that measure not only humidity, but also temperature.

Did you know?Pine cones are a natural hygrometer. They open at low temperatures and contract at low temperatures. high humidity air.

Collapse

Raising poultry is a painstaking and difficult task. In order for a chick to emerge from an egg, it takes several weeks to create special conditions for the development of the embryo. A psychrometer for an incubator is a device that will help you monitor the most important parameters. No owner can do without it.

Functions

Breeding poultry under incubation conditions is very popular, both in private farming and in mass production. Every owner knows that a chicken can hatch from an egg only if all the parameters are met.

Scheme of a homemade psychrometer

The main points in this matter are:

• temperature;
• air humidity.

If these indicators are lower or higher than standard, then even the most modern technologies can't turn an egg into a bird. Therefore, it is very important to monitor the humidity and heat in the middle of the incubator. This is where a psychrometer comes in handy.

This device is used on the farm to measure air parameters. In most cases, its purpose is to determine the percentage of air humidity.

But, with a complicated design, it is possible to additionally set the temperature in the middle of the incubator.

The device operates on the basis physical properties– evaporation of liquid. Having two thermometers, one of which is immersed in water, and the second remains dry, two indicators are determined.

Using a special table compiled by specialists, the humidity of the air in the incubator is directly displayed. That is, a psychrometer is a special device that can calculate air humidity using the difference in the readings of two thermometers.

In practice, using this device is very easy and convenient. A psychrometer for an incubator can be purchased in specialized stores. There is also an option self-made device.

The most popular device models and their characteristics

Kinds

Devices provided at modern market can be divided into three groups, using their operating principle as a criterion:

• aspiration;
• stationary;
• remote.

An aspiration psychrometer for an incubator is characterized by the presence of two thermometers, which are located in a special frame. This ensures that the device is less subject to negative influence and damage.

Air from the incubator is constantly blown onto the thermometers themselves with the same power using a special fan. As a result, the temperature is determined on thermometers. One of the advantages is the accuracy of the data, but the main disadvantage is the high price.

Stationary devices are located in the meteorological booth. It, in turn, is attached to the incubator using a tripod. The calculation of indicators occurs due to circulation air flow through the booth.

The disadvantage of the device is that a humidified thermometer can change data depending on the strength of the air flow, which is not the case in the previous version, since it is constant there. On the plus side, it is very easy to use and easy to repair.

Remote technologies involve the use of:

• resistance thermometers;
• thermistors.

The main characteristic of the devices is that the results are displayed on a part of the device outside the incubator. At the same time, in the middle there is a special sensor that constantly measures indicators.

The main advantage is the accuracy of the indicators. The errors of these devices are minimal, and the results are displayed to hundredths. The disadvantages include the high cost and complexity of repairs in the event of a breakdown.

Popular models

The most popular models among buyers from the types discussed above today are:

As we see, the most cheap option- a stationary device, and the most expensive is aspiration. But the high cost is justified by the high accuracy of the results.

The most common and simple device for measuring temperature and air humidity during the drying of wood in drying chambers ah is electronic psychrometer.

Operating principle and short description: The psychrometer consists of two thermometers: “dry” and “wet”. The “dry” one is just a thermometer, and the “wet” one has a wick made of cotton fabric, the ends of which are lowered into a bath of water.

Due to the hygroscopicity of the fabric, the water from the bath rises and wets the entire wick. Due to the evaporation of water from the surface of the wick, the temperature of the “wet” thermometer decreases and a temperature difference arises between the “dry” and “wet” thermometers. This difference is called the psychrometric difference.

The lower the air humidity, the greater the evaporation rate, and hence the psychrometric difference. Thus, the “dry” thermometer shows the air temperature in the chamber, and the psychrometric difference characterizes the humidity.

Relative air humidity is determined by temperature and psychrometric difference using psychrometric tables. There are several tables, since the evaporation rate also depends on the air flow speed. For drying chambers, a psychrometric table is suitable for an air flow speed of 2 meters per second. As a rule, they do not use a psychrometric table when drying wood, but simply set the temperature and psychrometric difference in the drying mode.

How to make a psychrometer

Option 1. An easy-to-manufacture electronic psychrometer with a water addition system, made on the principle of an automatic drinking bowl, is shown in the top photo on the left. It is made on the basis of two identical resistance thermometers. We recommend using copper thermometers (the letter “M” is present in the designation: M50, M100, and so on) since they have a linear nominal static characteristic. When choosing thermometers, pay attention to the environment in which they are intended. If the thermometer is intended for use only in a gaseous environment, water from the wick may leak into the thermometer and render it unusable. You need to take thermometers that are designed to work both in air and in water.

The “dry” thermometer is attached to the chamber wall using a corner. For a “wet” thermometer, a stainless steel bath is made. You can use (if you have one) a ready-made bath made of heat-resistant plastic, aluminum or other corrosion-resistant material. It is not recommended to make a bath from “ferrous” metal, as it will quickly rust, the rust will “clog” the wick and the psychrometer will begin to give incorrect readings of the psychrometric difference.

You should not make an excessively wide or long bath. This will lead to increased evaporation from the surface of the water in the bath and you will have to add water more often, but you don’t need that. If you find a ready-made bath, but it is too large, then make a lid for it with a slot for the wick.

The “wet” thermometer is installed at a height of 2-3 centimeters from the surface of the water in the bath. This height should not be made too high; this will impair the wettability of the wick and the psychrometer will give incorrect readings.

The tank for adding water to the bath is made from a regular aluminum canister. Canisters made of polyethylene and other plastics with a low melting point should not be used. The temperature in the chamber rises to 70 - 75 degrees. At this temperature, the walls of the canister made of such materials soften, lose their rigidity, the canister simply flattens and almost all the water flows out of it.

All production of the tank comes down to drilling a hole in the lid of the canister and installing a fitting on the lid (which can also be bought at a hardware store). When installing the fitting, it is recommended to coat the edge of the hole in the cover with automotive silicone sealant. This will ensure the necessary tightness of the connection. A hose is put on the fitting, if necessary, the hose is tightened with a clamp - the tank is ready.

How and why it works. Pour water into the canister, screw the lid tightly, lower the end of the hose into the bath and turn the canister over. Water will pour into the bath until it closes the hole in the hose, after which the flow of water will stop. It's simple: the canister is sealed, water is poured out until the free space in the canister is taken up by air entering through the hose. As soon as the air flow stops, the water flow stops. In the future, due to evaporation, the water level in the bath will decrease, the hole in the hose will open and a new portion of water will pour into the bath. This will continue until the water in the canister runs out.

The main disadvantage of option 1. When drying wood, a lot of water will evaporate from the bath. From our experience, 10 liters of water will last for 3 - 5 days (depending on the size of the bath, the drying mode and its stage). That is, as a rule, there is not enough water in the canister for all drying, so you have to stop drying, open the drying chamber and pour water into the canister. This in itself is neither convenient nor desirable, and if the psychrometer is also located in a hard-to-reach place...
Therefore if:

1. The drying chamber is located in a heated room.
2. There is a heated room next to the cell.
3. The psychrometer is installed in a hard-to-reach place.

Option 2 (middle and bottom photos). Everything is the same as option one, just adding another bath. This bath, together with the canister, is placed in an easily accessible place in the chamber (for example, near the technological door) or in warm room outside the camera. The tank bath (in the middle photo) and the psychrometer bath (in the bottom photo) are installed at the same level and connected to each other with a hose. As a result, the water level in both baths will always be the same (property of communicating vessels). This option is a little more complicated and more expensive: you will have to make not one, but two baths, buy not one, but three fittings and more hoses will be required. But the ease of use will quickly outweigh the costs.

The main mistake with this option is that if the hose is laid incorrectly, it becomes “aired” and water from the tank bath stops flowing into the psychrometer bath. The rule for laying the hose is simple: only one sag is allowed. If there are at least two of them, then an air plug may form in the upper part between them.

The advantages of option two are obvious: you can add water without entering the chamber and without stopping the drying; you can check the remaining water in the canister at any time.

Water. Distilled water is recommended to power the psychrometer. When drying hardwoods that have a long drying time, this condition is mandatory. When drying easily drying rocks, some deviations are possible. If tap water soft, then you can use it, but after each drying you need to rinse the wick in running water. If the water is hard, you can use softened water. Installations for water softening are available at any large boiler house; water can be taken from them. What to do, if hard water and there is no other one? Collect in summer rainwater, melt the snow in winter. It is not difficult.

Wick. The wick should be made only from natural cotton fabrics: chintz, cambric, batting, and so on. You can use regular gauze, folded into four layers.
It is recommended to check the condition of the wick before each drying. A clogged (salty) wick becomes hard to the touch. In this case, it must be removed and washed in running water (or replaced).
The wick should cover the entire working part of the thermometer. It is recommended to secure the wick to the thermometer, for example, with wire (see photos).

Place of installation of the psychrometer determined by the design of the drying chamber. For the chamber described in the article “Requirements for the design of drying chambers”, it is recommended to install the psychrometer on the wall of the chamber on the pressure side (from the side where the drying agent enters the stack of lumber), at a height of about 1.5 meters, in the middle of the length of the chamber.