The tree must be dried before use. A moisture meter is used to measure moisture outside and inside the workpiece. Most hygrometer models determine the moisture level in a log or log house with high accuracy. This is carried out at timber processing enterprises and in lumber manufacturing workshops.
The principle of operation of the device
Before the appearance of electronic moisture meters, the moisture level was determined according to GOST. This is a long and laborious process, which gave accurate indicators only with strict adherence to research algorithms. The disadvantage of this method is the difficulty in obtaining the value.
Moisture meters are designed for almost instantaneous determination of material moisture.. The principle of operation of devices is based on measuring the electrical resistivity of a tree. This parameter varies depending on the amount of water in the structure of the material, which the device responds to. Meters calculate the degree of humidity with an error of 0.5 to 4% according to several parameters:
Local measurements. In one trunk in different areas, the level of moisture saturation is different. To reduce inaccuracy, measurements are carried out in several places of the workpiece.
Different density in the rocks. Coniferous and deciduous trees have different characteristics. For example, by density. This feature can be taken into account by many moisture meters, the software of which includes the rock identification function.
The undoubted advantage of using a moisture measuring instrument over the GOST method is the preservation of the integrity of the product.
The main types
The principle of the hygrometer is the analysis of the specific resistance of the material to the passage of current, but the accuracy depends on the characteristics of the device. The device must be selected based on the purpose of its use and scale of production.
Conductometric needle hygrometer
The contact moisture meter is equipped with probes that must be inserted into the wood. In her body, the device creates an electrical impulse between the electrodes and determines the size of the resistance of the medium. The value is displayed on the screen.
Advantages of devices:
- low price;
- high reliability of the result with the correct introduction of needles into the mass;
- ease of use.
Disadvantages:
- it is necessary to damage the material, and this is undesirable when measuring hard and expensive rocks, finished products;
- An electro-moisture meter is unable to reliably measure humidity below 4%. This disadvantage is insignificant, less than 5% is the normal level of water content in the finished product.
The device rarely becomes unusable, for setup sometimes it is necessary to replace the crown, which you can do yourself.
Non-contact electric moisture meter (dielcometric)
The moisture meter has a built-in radio frequency generator. It scans building materials from a distance without the need to penetrate the mass.
Advantages of the device:
- an electric moisture meter can detect humidity with a low error;
- suitable for analyzing the quality of raw materials and finished wood products;
- in many models the function of memory of values is included;
- does not require wood damage.
Disadvantages:
- high cost of the device;
- repair of a moisture meter will be expensive, a specialist is required.
How to use the moisture meter: turn on the device, attach the contact surface to the material or take it to the distance indicated in the instructions. For devices, the working element can be located on the rear side of the device or as a remote measuring cylinder (see photos of contactless devices).
Hygrometer Overview
Psychrometers for measuring the amount of moisture in wood are used in the study of material in laboratories, in woodworking shops and in the manufacture of products. Large companies that are conscientious in their work conduct quality control of raw materials at all production stages. To do this, use devices with certain characteristics from different brands.
Needle gauges
- According to the characteristics, the EV 2K electric moisture meter (see photo) complies with the requirements of GOST 22261-76 and GOST 24447-80. This is an industrial moisture meter designed to work with all types of lumber from different types of wood. The conductometric model of the old model works by the contact method. Allows you to determine humidity at an air temperature of + 5–400 ˚C. The average price of the device is 2000 r.
- Moisture meter KWB 0121-00 is a modern Chinese conductometric device. He is able to measure and analyze the condition of wood, concrete and some other building materials. Its disadvantage is a low level of penetration into the material, as a result - a high degree of error. The function of automatic shutdown when idle extends the battery life. The average price is 2000 p.
- Needle wood moisture meters Gann (Germany) are used in wood drying and storage workshops. Different models measure at a depth of 5 to 40 mm in the range of 5 to 50%. The choice of model is based on the production needs of the enterprise. Price from 120 to 440 euros.
Contactless devices
- The moisture meter of building materials BCM-1 is a universal tool for determining the level of water saturation in wood, stone, concrete during the construction process and during repair work. 25 graduated dependencies can be entered into the device, which will reduce the value of the error of the result. The device is widely used in laboratory research. The average price of the device is high - about 35,000 p.
- Non-contact hydrometer hydrocondtroleasy - a domestic assembly device. Designed for rapid measurement of moisture in lumber according to GOST 16588. The device determines the amount of moisture inside large logs and beams along the entire length. Works with 7 groups of wood species. With the versatility of use, an electrometer is relatively inexpensive - from 5800 p.
- Merlin devices (Austria) are designed to measure moisture in wood of different thicknesses: in logs, boards, parquet, with a planed and unprocessed surface. The choice of model should be based on the thickness of the products being tested. One can call universal the merlin HM8-WS25 meter: the depth of the investigated surface is up to 40 mm, the analysis spectrum is from 4 to 99%. Convenient touch screen and intuitive interface make using the device accessible to any controller. The cost of the hydrometer is 37,000 p.
- The micro hydro control device measures the wetting of shallow layers, it is used in the manufacture of furniture, wood finishing materials, parquet, solid wood doors. The device is able to analyze 23 types of wood. The compact size of the hygrometer (see photo) and low price (about 3000 p.) Are its main advantages.
- The MG4U tree moisture meter is a universal device for determining the state of bulk and solid building materials. This is a hydrometer for sawdust, gravel and other bulk materials, as well as solid products. The software complies with the standards GOST 21718 and GOST 16588. The device is listed in the State Register. Price - about 43 000 p.
- The MG4B device is equipped with 13 calibration dependences of solid materials from stone of different densities and 15 algorithms for wood. The characteristics are similar to MG4U, adapted for working with solid materials. The price is 32 000 r.
- ADA ZFM brand meters are designed for hard and soft wood, drywall, and brickwork. The work surface is on the back of the appliance. Measurement range - 0–100% humidity, measurement accuracy ± 4%. The cost of the product is 2200 p.
For convenience of choice
To easily select a moisture meter, we will bring the presented models to a table with the main technical indicators.
Index | Device type | Range of measurement of humidity,% | Depth of measurement, mm | Accuracy, ±% | price, rub. | Country |
EV 2K | Needle | 7-22, 22-60 (2 ranges) | 20 | 2…3 | 2000 | Russia |
KWB 0121-00 | Needle | Up to 30 | Up to 40 | 2…4 | 2000 | China |
Gann (generic values presented) | Needle | 5 ... 50 (depending on model) | Up to 40 mm | 0,5 | From 8400 | Germany |
BCM-1 | Dielcometric | 5…40 | Not less than 50 | 0,3…2,0 | From 33,000 | Russia |
hydrocondtroleasy | 2…65 | 30-40 | 1,0…2,0 | 5200 | Russia | |
microhydrocontrol | 2…65 | 30 | 1,0…2,5 | 3000 | Russia | |
MerlinHM8-WS25 | 4…99 | 25…40 | 1,0 | 37 800 | Austria | |
MG4U | 4…35 | 40…50 | 1,5…3,0 | 43 000 | Russia | |
MG4B | 1…45 | Up to 40 | 1,5…2,5 | 32 000 | Russia | |
ADA ZFM | 0…100 | 30…40 | 1…4,0% | 2 000 | China |
Hydrometers differ in basic parameters: the accuracy of determination, the presence of identification of different tree species, the depth of transmission of the measuring pulses. It is on these characteristics that you must rely on when choosing a device. The size of the error also matters: for the production of critical products, it is necessary to obtain accurate and reliable data. On the other hand, in production, the device is useful for measuring the moisture content of the barrel - raw materials, and the condition of the finished board after drying. In all cases, different characteristics of the hygrometer are required.
Tabular data may differ from the actual ones, information is for information only. More accurate specifications will provide sellers.