Bedömning av tre in-line fuktkvotsmätare för trä
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
The vision of wood as an engineering material and a first choice in buildings, constructions and furniture production put high demands on measuring equipment which can define and determine the quality of boards and planks. The moisture content in wood is a quality factor that is all too often badly described when sawn goods is delivered, but still it is an important factor in the further processing. This thesis is a part of a project, where the objective is to find or develop measuring equipment which can determine the moisture content between 7 to 18% MC with an accuracy of ±1 % (90 % confidence interval). Within the frames of this thesis, three moisture content meters for inline use where tested. A test material with five wood classes was produced. Each class included approximately twenty pieces. The intention with the wood classes was to find differences between the meters in how they handle different types of wood. Two of the equipments were tested in industry and the third in the lab. The meters were calibrated with the same material within the span 8 to 17,5 % MC. The test material was then fed through the meters and the values were logged. The results were analyzed in regard to the measuring technique or method the meter was using. According to the results, there are differences between the methods. The MC meter which is using the capacitance method shows too high values when measuring high density pieces compared to low density pieces with the same moisture content. This is a result of the nature of capacitance, which mostly depends on the amount of water and not the fraction between water and wood. The results also showed that the meter which used the shortest wavelength (microwaves) measured too high values in and around knots. The reason for this behavior is unclear, but could be explained by diffraction around the knot due to the higher density. In general, the MC meters showed good accuracy.
Place, publisher, year, edition, pages
2011. , 38 p.
Teknik, microwave, dielectric properties
IdentifiersURN: urn:nbn:se:ltu:diva-42335Local ID: 05b7d17b-7796-49bd-b93f-b5bbd93856f2OAI: oai:DiVA.org:ltu-42335DiVA: diva2:1015555
Subject / course
Student thesis, at least 30 credits
Wood Engineering, master's level
Wamming, ThomasAntti, Lena
Validerat; 20110402 (anonymous)2016-10-042016-10-04Bibliographically approved