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Wireless Lignomat Probe System for Lumber Drying
Lignomat has developed wireless probe systems to make kiln drying more efficient and user-friendly.
Date Posted: 7/1/2010
Lignomat has developed wireless probe systems to make kiln drying more efficient and user-friendly. This is true for standard steam kilns, and predryers. The wireless measuring system is especially beneficial in predryers, where long cables can be avoided and moisture sensors and humidity sensors can be freely moved within the kiln. The same is true for monitoring air-drying yards; no cables are required and the measuring sensors can be moved from stack to stack.
Another application is heat treatment for lumber to make sure that all bugs are killed and the lumber can be shipped.
The flexibility of the system and the easy integration into any existing kiln operation has made the wireless in-wood temperature sensors popular.
The moisture content (MC) of wood is measured with 2 teflonized probes, which stay in the wood during the drying process. The probes are connected with a short cable to a transmitter placed between the stacked lumber. The receiver installed at the kiln wall picks up the measuring signal. This works the same as if a moisture meter with pins were permanently installed within the stack.
The air humidity (EMC) is measured in a very unique way by a cellulose wafer, which adapts to the climate in the kiln. No wet-bulb thermometer is needed. The EMC sensor is an inexpensive, interchangeable cellulose wafer, which is a non-electronic sensor that is not influenced by electric interferences or wood acids. The EMC sensors provide accuracy and user-friendliness.
The technology for placing the measuring circuitry in the hostile environment of a kiln has not been available in the past. For that reason, long cables were needed to connect the sensors to the measuring device or controllers located outside of the kiln. These long cables reduce the accuracy of the readings because the sensitive, low-level analog signals being carried can easily be distorted by leakage currents along the cable or by interference from electromagnetic noise. The cables are also cumbersome for the kiln operator when loading and unloading the kiln as well as when entering and leaving the kiln during the drying process.
With the introduction of the wireless probe technology, the sensor cables becomes obsolete, thus eliminating the problems described above. According to Lignomat, forced-air drying sheds, drying yards, and pre-dryers can now be easily monitored from one central location. The system replaces in-kiln wiring for less maintenance. For open air-drying, any number of transmitters can be used to monitor the entire yard from a PC using standard tools like Microsoft Access.
The new Wireless Probe System further is designed to improve the accuracy, user-friendliness and cost of data acquisition systems used for lumber drying. Thanks to its standard serial interface, it can be part of any kiln control or moisture monitoring system. For further information, please contact Lignomat USA, Ltd. at (800) 227-2105.
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