Hygrometers

Knowing the proper moisture content when working with concrete is essential to guaranteeing its quality and longevity. Here’s where hygrometers are useful. A hygrometer is a vital tool for anyone working with concrete construction or maintenance, as it measures the amount of moisture in the air or within materials.

For concrete to cure properly, the ideal moisture content must be met. An abundance of moisture can cause problems such as surface imperfections, the growth of mold, and compromised structural integrity. Conversely, too little moisture can lead to cracks in the concrete and prevent it from strengthening to its full potential. In order to make sure that the concrete cures as planned, hygrometers assist in monitoring these moisture levels.

Hygrometers come in a variety of forms, each appropriate for a specific use. Some are specifically made to measure the moisture content of the concrete itself, while others are made to measure the humidity in the air surrounding the concrete. Knowing the distinctions between these kinds will assist you in selecting the best tool for your particular requirements.

Hygrometer operation is simple, but for accurate readings, it’s crucial to adhere to the manufacturer’s instructions. Throughout the curing process, regular monitoring of moisture levels can help avert potential issues and guarantee the longevity of your concrete structures. Purchasing a high-quality hygrometer will ensure that your concrete work will last for many years, which is a small price to pay.

What kind of device is it and what is it for?

A hygrometer is a type of measurement tool used to calculate humidity. It is employed in a number of activity domains to track the indicator. There are numerous device types available today, each with a unique operating system.

The Greek term hygrometer (ὑγρός "liquid" + μετρέω "I measure") refers to a liquid meter. Gyroscope is another Greek term (hygro = wet + metron = measure). The apparatus gauges:

• percentage of air humidity;
• can be used in work with other gases.

Contemporary hygrometers vary in:

1. type;
2. operating principle;
3. purpose and design.

What it looks like: description and photo

The class to which a device belongs determines its type.

Hygrometers come in a variety of classes, each operating on a distinct set of principles:

1. weight;
2. conductometric;
3. hair;
4. condensation;
5. electronic.

Items need to have a body and several ways to display the results, such as a dial, scale, or display with numerical values.

What can be measured using the unit?

The instrument is meant to measure the moisture content of gases. The primary indicators that a hygrometer measures are:

1. Absolute humidity. The indicator displays the weight of water vapor present at the time of measurement in 1 cubic. meter. of the atmosphere.
2. Relative humidity. This is a parameter that characterizes the amount of moisture at the time of measurement closest to the maximum value for a given temperature. The measurement is made in % and is most often used to describe the meteorological situation.
3. Dew point. This is the temperature at which water vapor condenses from the air on a cold surface.

Data for one indicator can be converted into others after it has been received.

For instance, you’ll need to use the required formula and a few quick calculations to get the dew point from relative humidity.

The hygrometer’s range of applications is extensive. In many industries, humidity control is essential as it provides solutions for multiple issues. Producers are attempting to create gadgets meant for particular uses and missions. As an illustration:

1. Long-term storage of agricultural products. Constant humidity control is necessary to create and maintain temperature and humidity conditions in the room.
2. Storage of medications requiring certain conditions. Many medicines lose their properties in conditions of excess humidity.
3. Maintaining a microclimate in libraries and archives. Old books and old materials can be destroyed by excess moisture.
4. Monitoring the humidity of building materials. First of all, this concerns the degree of drying of wood and determining the humidity of concrete.
5. Checking materials in furniture production. This is necessary for precise compliance with the technological process and increasing the service life of finished products.

Professional portable hygrometers are also available for use in the chemical and oil and gas sectors. The non-aggressive gas mixtures are also monitored by these devices. The apparatus finds applications in nuclear power plants, the energy sector, microelectronics manufacturing, and natural gas drying.

Anybody working with concrete needs a hygrometer; they measure the moisture content of the concrete and the air, which helps to ensure ideal curing conditions and avoid problems like warping and cracking. Hygrometers are essential tools for both building and maintaining concrete structures because they precisely measure humidity, which aids professionals in preserving the strength and longevity of these structures.

Scheme and design of a humidity meter

A modern device consists of a case that conceals a mechanism for measuring humidity. The kind of device determines how this mechanism is designed.

A hygrometer device typically consists of the following design elements:

• sensing element (usually capacitive);
• resistance converter;
• protective filter;
• housing;
• electronic measuring transducer.

The delicate component needs to be shielded from mechanical harm. Batteries or another power source is needed for electronic models. This is a wireless design if they are concealed within the housing.

Certain hygrometers are wired, meaning that the indicator is situated at the end of the wire. This is useful for taking measurements in locations that are difficult to access. There are digital gadgets and ones that run on batteries. The humidity level is shown on digital hygrometers’ displays.

Analog models feature a dial and an arrow.They are in contact with the environment under study through a sensor. There are two kinds: external and internal (used to measure the humidity of the surrounding air). The latter is employed in measurements at a particular location.

The device’s working principle is derived from the physical process of cooling water through evaporation. Electrolytic hygrometers will yield the most accurate measurement. Such a device will not wear out and will function for a very long time if stored properly.

The way a conventional analog hygrometer operates is by altering hair length. The arrow’s location on the scale is fixed by the material’s tension. Error: up to 7%. This is irrelevant for home use; other devices are used for professional activities.

Diagram of a hair device: complete details regarding the diagrams in this piece.

Characteristics

The device has several main characteristics:

1. Accuracy class. According to GOST 23382-78, the following accuracy classes are established for hygrometers – 0.5; 1.0; 1.5; 2.0; (2.5). Depends on the type of sensor used.
2. Units of measurement or metric system. If the devices determine the relative humidity of the air, the result is displayed as a percentage from 0 to 100. For models showing dew point, the result is displayed in degrees Celsius. To indicate absolute humidity in the international system of units, kg/m3 is used, and in the physical system of units – g/cm3.
3. Error. The limit of permissible basic absolute error caused by changes in external influencing quantities depends on the accuracy class of the hygrometer. The values ​​of deviations are indicated in Table. 1 GOST 23382-78.

Generally, the measurement range is 0% to 100%; occasionally, it can be as much as 20% to 100%.

Various measurement ranges are available for multifunctional devices, contingent on the material being utilized.

Types

Different operational principles underpin the various modern varieties of hygrometers. The principal ones are:

1. Hair. The design contains human hair. The operating principle is based on the ability of hair to curl or straighten when the degree of air humidity changes.
2. Psychometric. It has two thermometers, the difference in readings of which is used to calculate the air humidity.
3. Electronic. Very simple device for users. All data is displayed on a digital display. Modern models are equipped with additional functions – temperature measurement, lighting, day of week and time display, alarm clock.
4. Condensation. Gives the most accurate readings, but has large dimensions.
5. Weight. Consists of several tubes connected to each other. The tubes contain a hygroscopic substance. The calculation is based on the difference in the weight of the system before and after passing a portion of air. It has very accurate results, but is inconvenient for the average user – the need for calculations using special formulas.
6. Ceramic. In this model, the sensor is a special ceramic mixture (hard and porous). It is capable of changing its electrolytic resistance depending on humidity.

Hygrometers come in a variety of forms and styles, as well as being wall-mounted, tabletop, contact, and contactless.

Read the complete types article here.

Adjustment and setup of the device

The gadgets are shock and vibration sensitive. Hygrometers are therefore offered without calibration. Without any adjustments, the device’s readings could be very different from the real humidity level.

The device needs to be calibrated after purchase. The idea behind this procedure is to set up the device in a known humidity environment. After that, its readings must be changed to reflect the known value.

The device has a screw on the back panel for these purposes; turning it causes the readings to change. The adjustment is complete when there is no longer any disparity. You must take the model apart and rotate the dial in relation to the arrow if there are no screws. Using a second, previously calibrated device is recommended. It must be positioned next to the new one and have the same settings made.

The new device will have an error similar to the old one’s if it has inaccurate readings.

There are two additional methods:

1. Quick. You need to wrap the hygrometer in a damp cloth and place it in a plastic bag. In a closed space, the moisture will evaporate to a humidity value of about 96%. This will take about 1 hour. Then you need to take out the hygrometer and set the arrow to 96%. However, this method is considered inaccurate.
2. Long. Place the hygrometer in a sealed box containing a saturated solution of table salt. Next to a saturated saline solution, the humidity is 75%. This method will take eight hours. After 8 hours, you need to take out the hygrometer and set the arrow to 75%. This method is considered very accurate, you can trust it.

You should instantly move the arrow to the desired location in both cases.

The hygrometer will start to adjust its readings to reflect the humidity of the surrounding air as soon as it is taken out of the artificial environment. The calibration will need to be redone if the readings are not set in a minute.

This page contains all the calibration information.

Use rules

Depending on the kind of device, there are different ways to use hygrometers. There must be usage instructions included with the device. Strict adherence to every point in the document is the only way to guarantee that the outcome is accurate.

Electronic

These hygrometers are simple to use. They are instantly usable and don’t require any adjustments. The hygrometer must first be visually inspected to make sure there is no mechanical damage. Next:

• turn on the device;
  set the time, day and other data;
• wait a little while the device calculates the humidity indicator;
• view the result on the display.

An extremely handy version for usage at home.

This is a complete article about electronic types.

Mechanical

This kind of hygrometer is thought to have average accuracy. There is a 5-8% error rate. The device must first be calibrated using a reference hygrometer. After that, put it somewhere permanent—a table or wall—and start taking readings. Devices can record not only the humidity level but also the temperature.

Basic guidelines for using any kind of device:

• protect the device from falling;
• prohibit processing with solutions containing aggressive substances;
• do not overheat (the permissible limit is specified in the instructions);
• if you need to use water, then take distilled.

Details about usage can be found at the link.

Service life and verification

The device passport specifies both intervals. Confirmation of the hygrometer’s compliance with the specified requirements is done through verification.

The error values are examined and contrasted with the allowable deviations throughout the verification process. A determination is made regarding the device’s suitability (or unsuitability) for continued use once the verification is complete.

The time between hygrometer verifications varies from one to two years, depending on the model.

The gadget is covered under a one-year warranty. The quality of use and the environment in which the device is used determine how long it will last.

Here are specifics regarding life in the service.

How to do it yourself?

You can assemble the device in a variety of ways. The master’s expertise and abilities, in addition to the materials’ accessibility, determine the kind of design. Let’s look at the most straightforward solutions that don’t require any advanced electronics or physics knowledge.

Option 1

You can take the measurement once in this situation. After that, the whole thing needs to be done again. A functional refrigerator, clean water, and a standard glass are required. Fill the glass with water, then place it in the fridge. To measure humidity, take out the glass and place it in the room once the water has cooled.

The glass should be placed away from heating devices.

There are three possible ways the result can appear:

1. With overdried air and a low percentage of humidity, condensation will appear on the walls of the container, but after 5-7 minutes it will begin to gradually disappear.
2. With high humidity in the room, condensation will flow down in drops.
3. With a normal level of humidity, neither condensation nor drops will appear on the walls of the glass.

Although the precise indicator is not provided by this method, the overall humidity level will show.

Option 2

More precise, but needs specific tools and procedures. You’ll require:

• 2 thermometers;
• a piece of cloth;
• distilled water and a container for it.

Additionally, a panel (wood or plastic) for mounting a home hygrometer is required.

1. Attach 2 thermometers to the panel. They should be located parallel to each other.
2. A cup of water should be placed under one of them.
3. Wrap the lower part of the thermometer, where the mercury is, in cotton fabric. Tie with a thread and attach.

Immerse the fabric’s edge 5 to 7 cm into the water. We’ll refer to this thermometer as "wet" and the second as "dry." The humidity level is determined by taking the difference between their readings.

This article has more information about manufacturing.

Here are the steps to make a hair hygrometer, as shown in the video:

What are the pros and cons?

The device’s ability to measure the room’s humidity is its primary benefit. Other factors could change based on the kind of product.

Benefits

• durability;
• variability of designs;
• wide measurement range;
• high enough accuracy;
• small error range;

Drawbacks:

• dimensions (depending on type);
• difficulty of measurement and adjustment;
• cost;
• the need for systematic verification.

User reviews in brief

Customers observe the benefits of the goods:

• compactness;
• practicality;
• durability;
• visibility;
• accuracy.

Cons:

• Some models do not have instructions in Russian;
• complexity of setup;
• need for constant maintenance.

How much do they cost in Russia and what does the price depend on?

Cost varies. As an illustration:

• 399 — 2800 rubles — household thermohygrometer;
• 1489 — 3500 rubles — pharmaceutical hygrometer;
• 1500 — 2700 rubles — psychometric.

The type of design, manufacturer, retail location, availability of extra features, and material type all affect how much a device costs.

Hygrometer Type	Description
Digital Hygrometer	Uses electronic sensors to measure humidity levels quickly and accurately.
Analog Hygrometer	Features a dial and pointer to indicate humidity, often using a coil and spring mechanism.
Psychrometer	Consists of two thermometers, one dry and one wet, to measure humidity through evaporation.
Hair Tension Hygrometer	Uses the properties of human or synthetic hair, which changes length with humidity.

In the construction industry, hygrometers are indispensable instruments, particularly when handling concrete. They assist in determining the air and concrete’s moisture content, ensuring that the substance is appropriate for use and will set properly. Adequate moisture content is essential for concrete structures to be strong and long-lasting.

Hygrometers come in different varieties with varying features and precision levels, including digital, analog, and psychrometer models. The environmental factors and the particular requirements of your project will determine which hygrometer is best. While analog hygrometers are prized for their dependability and simplicity, digital models are frequently chosen for their accuracy and user-friendliness.

Effective hygrometer use requires routine calibration and upkeep to guarantee accurate readings. This aids in preventing problems with concrete curing poorly, shrinking, and cracking. You can extend the life and quality of your concrete projects by keeping a close eye on moisture levels.

Including hygrometers in your building process is a proactive way to get the best outcomes. These tools offer vital information that helps you make decisions and preserve the integrity of your work. The results of your concrete construction can be greatly enhanced by knowing how to use hygrometers, whether you’re a professional builder or a do-it-yourself enthusiast.

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