ANALYSIS OF QUALITY OF DRYING OF SAW-TIMBERS ON THE FINAL STAGE OF TECHNOLOGICAL PROCESS OF DRYING
Ihnatenko Paul, Chernihiv National University of Technology (95 Shevchenka Str., 14027 Chernihiv, Ukraine)
Ihnatenko Elena, Chernihiv National University of Technology (95 Shevchenka Str., 14027 Chernihiv, Ukraine)
Sapon Serhii, Chernihiv National University of Technology (95 Shevchenka Str., 14027 Chernihiv, Ukraine)
Urgency of the research. The quality indicators of lumber drying influence on formation quality indicators of wood products considerably, especially on the stability of the size and form of details.
Target setting. As a result of drying wood transforms from natural raw material into industrial material, which corresponds to the most varied requirements, which produce for him in different production and domestic terms. After the drying process is possible discrepancy humidity of lumber the established requirements, that requires additional processing.
Actual scientific researches and issues analysis. In Ukraine, professor P.V. Biley, V.M. Pavlyust are engaged in development of technological processes of drying and wood protection. Research on the automation of drying lumber carries company Holtek Semiconductor Incorporated, Taiwan. The works by A.M. Eroshenko and S.V. Boyko are devoted to technological process of composite materials drying.
Uninvestigated parts of general matters defining. When changing the humidity content in the wood assortment their size and form change. In cases, when during exploitation of wood products the stability of the size and form of details are needed, their humidity should be taken to the certain level, which corresponds to the operating conditions of these products, that is, to the operational humidity.
The research objective. Analyse the quality indicators of lumber drying and offer a method for the end of the technological process of drying.
The statement of basic materials. The lumber drying quality is characterized by a number of indicators, the main of them are:
- Visible defects drying;
- The average value of final humidity;
- The uniformity of the final humidity;
- The difference in humidity in thickness;
- Residual stresses.
The drying quality indicators are set for a specific batch of wood. For such a batch usually takes a stack of boards or workpieces.
Difference of humidity in thickness is controlled by sections layered humidity, which cut out from the selected boards beside the sections for determination the total humidity.
Residual stresses in the dried material is set for the power section, which cut out beside the waterline sections humidity from each of the selected board.
Conclusions. To ensure the necessary quality of lumber the end of drying process should be carried out as follows. After as material is achieved the desired final humidity (which is set by the control samples) the wet heat treatment appoint. At run time, the control operations in the chamber air-conditioning carry out. If determined that the material does not meet the necessary requirements, it should be assigned an additional wet heat treatment (in the presence of residual stresses in the material) or continued conditioning (when unacceptable vibrations final humidity range).
indexes of quality, saw-timbers, technological process, conditioning, chamber drying
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