Moisture Meters for Wood, Timber, Veneers, Plywood, etc.

<body text="#3333FF" bgcolor="#FFFFFF" link="#000000" vlink="#666666" alink="#FF0000" background="../../bckground.jpg"> <h1> <b><font face="Arial,Helvetica"><font color="#FF0000"><font size="+1">MOISTURE METER FOR WOOD</font></font></font></b></h1>   <table WIDTH="100%" > <tr VALIGN=TOP> <td><font face="Arial,Helvetica"><font color="#3333FF">Our successfull series of small measuring instruments can be used everywehre when it is necessary to quickly and reliably determine the moisture content of materials.</font></font> <p><font face="Arial,Helvetica"><font color="#3333FF">There are some additional interessting meters which are made <b><a href="../wood&building/index_wood&building_e.htm" target="Rechts">for wood and building materials </a></b>with sensors for temperatures and rel. humidity in air too.</font></font> <p><b><font face="Arial,Helvetica"><font color="#3333FF">Additional Informations:</font></font></b> <ul> <li> <font face="Arial,Helvetica"><font color="#3333FF"><font size="-1"><a href="#capacitive">capacitive measuring principle</a></font></font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF"><font size="-1"><a href="#conductance">conductance measuring principle</a></font></font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF"><font size="-1"><a href="#compare">comparing capacitive and conductance measuring principles</a></font></font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF"><font size="-1"><a href="#drying_method">drying method DIN 52183, ISO 3130-1975</a></font></font></font></li> </ul> <b><font face="Arial,Helvetica"><font color="#3333FF">Moisture Meters:</font></font></b> <ul> <li> <font face="Arial,Helvetica"><font color="#3333FF"><font size="-1"><a href="moisture_meter_gm53/gm53-e.html">type GM53, GM54 with bar graph display and capacitive measuring principle</a></font></font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF"><font size="-1"><a href="moisture_meter_lwm2/lwm2-e.html">type LWM2 with digital display and conductance measuring principle</a></font></font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF"><font size="-1"><a href="moisture_meter_hd1/hd1-e.html">type HD1 with digital display and capacitive measuring principle</a></font></font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF"><font size="-1"><a href="../dm4a/dm4a_e.html">type DM4A with digital display and capacitive measuring principle</a></font></font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF"><font size="-1"><a href="moisture_meter_h2470/h2470-e.html">type H24/70 with analog display and capacitive measuring principle</a></font></font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF"><font size="-1"><a href="moisture_meter_hd7/hd7-e.html">type HD7 with digital display and capacitive masuring principle especial for veneers</a></font></font></font></li> </ul> </td> <td><img SRC="../../holz2.jpg" BORDER=0 height=305 width=250></td> </tr> <tr> <td><font face="Arial,Helvetica"><font size="+1"><a href="../../index.htm" target="_top">home</a></font></font></td> <td></td> </tr> <tr> <td> <hr SIZE="1" WIDTH="100%"></td> <td></td> </tr> <tr VALIGN=TOP> <td> <h2> <a NAME="capacitive"></a><b><font face="Arial,Helvetica"><font color="#3333FF"><font size="+0">Capacitive Measuring Method</font></font></font></b></h2> <font face="Arial,Helvetica"><font color="#3333FF">This is the most cost effective measuring principle to measure the moisture without damaging the material. </font></font> <p><font face="Arial,Helvetica"><font color="#3333FF">The meter are  working in accordance with the principle of an opened plate capacitor. The capacity of the capacitor depends on the material-(dielectric)-constant (DC) of the material in between the plates. Compared with air, for example (DC = 1) water has got a very high dielectric-constant (DC ~ 80). The water content of a wet material can therefore be determined by determining the dielectric constant of this material.</font></font> <p><font face="Arial,Helvetica"><font color="#3333FF">The measurements are influenced through differences in the material densities.</font></font></td> <td><img SRC="../../instr-alle-prinzip.jpg" BORDER=0 height=185 width=248> <DL> <i><font face="Arial,Helvetica">(1) field lines</font></i></DL> <DL> <i><font face="Arial,Helvetica">(2) material to be measured</font></i></DL> <br><i><font face="Arial,Helvetica">(3) plate capacitor</font></i></td> </tr> <tr> <td> <hr SIZE="1" WIDTH="100%"></td> <td></td> </tr> <tr> <td> <h2> <a NAME="conductance"></a><b><font face="Arial,Helvetica"><font color="#3333FF"><font size="+0">Conductance Measuring Method</font></font></font></b></h2> <font face="Arial,Helvetica"><font color="#3333FF">At least two electrodes has to contact the material which has to be measure in the depth where the moisture value needs to be known. An amplifier measures the electrical resistance and a  linerisation module calculates the moisture value. The electrical resistance is also influenced through temperature differences, salt concentrations and the contact to the material. It's necessary to damage the floorings for measuring in the wished depth.</font></font></td> <td></td> </tr> <tr> <td> <h2> <a NAME="compare"></a><font face="Arial,Helvetica"><font size="+0">Compare of Capacitive- and Conductance Measuring Principle</font></font></h2> <table BORDER WIDTH="100%" > <tr> <td><b><font face="Arial,Helvetica"><font color="#3333FF">capacitive measuring principle</font></font></b></td> <td><b><font face="Arial,Helvetica"><font color="#3333FF">conductance measuring</font></font></b></td> </tr> <tr> <td><font face="Arial,Helvetica"><font color="#3333FF">non destructive! - the sensor needs only to be pressed on the wood surface, the measuring depth is approx. 3 cm</font></font></td> <td><font face="Arial,Helvetica"><font color="#3333FF">at least two nails have to be pressed or nailed into the wood, the penetration depth of the nails is the measuring depth</font></font></td> </tr> <tr> <td><font face="Arial,Helvetica"><font color="#3333FF">very quick measurements, only press the sensor on the surface and read off the moisture value</font></font></td> <td><font face="Arial,Helvetica"><font color="#3333FF">measurement takes more time caused throgh the necassary nailing of the sensors into the wood</font></font></td> </tr> <tr> <td><font face="Arial,Helvetica"><font color="#3333FF">the result is an average moistrue value till a depth of approx. 3 cm</font></font></td> <td><font face="Arial,Helvetica"><font color="#3333FF">the highest moisture value between the electrodes is most effective to the moisture result</font></font></td> </tr> <tr> <td><font face="Arial,Helvetica"><font color="#3333FF">in the temperature range 5 - 40°C there is nearly no influence of the temperature to the moisture results</font></font></td> <td><font face="Arial,Helvetica"><font color="#3333FF">there is a big influence ot the temperature to the measuring result</font></font></td> </tr> <tr> <td><font face="Arial,Helvetica"><font color="#3333FF">the measuring field penetrates also coated and painted surfaces without damaging. </font></font></td> <td><font face="Arial,Helvetica"><font color="#3333FF">on coated or painted surfaces, measurings without damaiging the surface are not possible</font></font></td> </tr> <tr> <td><font face="Arial,Helvetica"><font color="#3333FF">for exact measurings, an flat surface is important</font></font></td> <td></td> </tr> <tr> <td><font face="Arial,Helvetica"><font color="#3333FF">differences in the density of dry wood may cause additional errors</font></font></td> <td></td> </tr> </table> </td> <td></td> </tr> <tr> <td> <hr SIZE="1" WIDTH="100%"></td> <td></td> </tr> <tr> <td> <h2> <a NAME="drying_method"></a><b><font face="Arial,Helvetica"><font color="#3333FF"><font size="+0">Drying Method</font></font></font></b></h2> <font face="Arial,Helvetica"><font color="#3333FF">The drying method is the most accurate measuring principle. Therfore we recommend for comparing measurements and also for calibrating or checking all electronical meters to carry out measurements with the drying method as described in the German DIN 52183 or ISO 3130-1975.</font></font> <p><font face="Arial,Helvetica"><font color="#3333FF">The measurement should be done with the following steps:</font></font> <ul> <li> <font face="Arial,Helvetica"><font color="#3333FF">you need a balance (we recommend a measuring range 200g and solution 0,01g) and an drying oven with temperature regulation for 104°C</font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF">cut  a small probe (approx. 100 g ) with a sharp saw, avoid border parts</font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF">take immediately the exact weight of the probe, name it W1</font></font></li> <li> <font face="Arial,Helvetica"><font color="#3333FF">put the probe in the temperature regulated oven and dry the probe till the weight is constant.</font></font></li> <br><font face="Arial,Helvetica"><font color="#3333FF">the maximumn drying temperature should be 104°C, the dried probe is named W2</font></font> <li> <font face="Arial,Helvetica"><font color="#3333FF">calculate the moisture M with the following formula:</font></font></li> <br><b><font face="Arial,Helvetica"><font color="#3333FF">M = 100% * (W1 - W2) / W1</font></font></b></ul> </td> <td></td> </tr> <tr> <td> <hr SIZE="1" WIDTH="100%"></td> <td></td> </tr> <tr> <td><b><font face="Arial,Helvetica"><font size="+1"><a href="../../index.htm" target="_top">home</a></font></font></b></td> <td></td> </tr> </table> <blockquote> </blockquote> </body>