Grigory Torgovnikov

Microwave wood modification technology and its applications.

The use of microwave (MW) technology is growing in all industries. This increased use has resulted from the high efficiency of converting electricity into MW energy; energy savings associated with rapid, in-depth heating of materials; specific interactions that can be achieved between MW energy and materials; radical acceleration of technological processes; reductions in MW equipment costs; and improvements in the reliability of industrial MW equipment. The new technology of MW wood modification is based on the supply of high-intensity MW power, up to 135,000 kW/m3 at frequencies of 0.922 and 2.45 GHz. Such power induces significant changes to the microstructure of wood and a dramatic increase in wood permeability. A number of commercial applications have been developed based on the fundamental changes in wood structure. These include the treatment of refractory wood species with preservatives, rapid drying of hardwoods, relief of growth and drying stresses in timber, manufacture of the new wood materials...

Method of check analysis of microwave-modified wood

A photo-based method for statistical image analysis of microwave (MW)-modified timber was developed and applied to test sets of Radiata pine and eucalypt hardwoods (Messmate and Mountain Ash). The method is based on filling the checks in timber with stain solution and analysing the wood surface. Bethel impregnation process (in a pressurised treatment vessel) was used to produce uniform surface staining of the test samples. Image processing was automated and the number of manual operations (the human decision-making process) was minimised. A computer program that automates thresholding and a program that repairs the threshold image were written. The software allowed larger images to be analysed and reduced image processing time. The described method produced reliable check measurements and statistics for softwoods. Though suitable for estimating the quality of individual MW-modified hardwood specimens, the method was found to be inadequate for statistical analysis of eucalypt hardwoods because of collateral staining of vessels accompanied with a high level of stain penetration into the wood tissues.

Microwave surface modification of Pinus radiata peeler cores: technical and cost analyses.

Radiata pine (Pinus radiata) peeler cores are classified as a by-product of plywood manufacture and have the potential for development as value-added solid wood products. This article outlines technical and cost analyses of microwave surface modification of radiata pine peeler cores along with the methodology, including measurements of temperature distribution and of preservative uptake and distribution following microwave heating. After microwave treatment, the highest temperatures are observed on the surfaces of the peeler cores. A gradual decrease in temperature is noted with depth within the timber. Chromated copper arsenate uptake after pressure impregnation ranges between 94 and 314 liters/m 3 . This uptake is three to nine times higher than that of control timber (no microwave treatment). Cost analyses focus on the microwave treatment of peeler cores and indicate that microwave modification costs range from US

High-intensity microwave wood modification for increasing permeability.

0.95 to US

Method for increasing the permeability of wood

1.23 for one peeler core (i.e., US

Modifield wood product and process for the preparation thereof

29 to US

Microwave modification of Radiata pine railway sleepers for preservative treatment

37 per m 3 ), depending upon electricity charges and the number of working shifts employed.