EVALUATION AND COMPARISON OF QUALITY EVALUATION AND COMPARISON OF - PowerPoint PPT Presentation

EVALUATION AND COMPARISON OF QUALITY EVALUATION AND COMPARISON OF QUALITY OF BEECH WOOD (FAGUS SILVATICA L.) AFTER VACUUM DRYING AND HF-DRYING VACUUM DRYING AND HF DRYING. Daniel Karpinský

Prong test - Casehardening

ENV 14464 - Casehardening

GOST 11603-73 - Internal stress

Drying time � Vacuum drying I (with equalizing) => 92 h � Vacuum drying II (without equalizing) => 72 h � HF drying (after 160 h pre-drying) => 10,5 h 100,0% 90,0% 80,0% 70,0% ) (% C 60,0% M M e g 50,0% n ra e 40,0% v A 30,0% 20 0% 20,0% 10,0% 0,0% 0,0 10,0 20,0 30,0 40,0 50,0 60,0 70,0 80,0 90,0 100,0 Drying time (h) y g ( ) vacuum I vacuum II HF drying

Results Final MC Final MC � Vacuum drying I => 2,9 – 3,2 % � Vacuum drying II V d i II => 3 7 3,7 – 4,8 % 4 8 % � HF drying => 6,1 – 7,5 % 8% 7% %) isture content (% 6% 5% 4% 3% Moi 2% 2% 1% 0% 1 2 1 2 1 2 3 4 Vacuum drying I acuu d y g Vacuum drying II acuu d y g HF drying d y g Drying / Sample

Results MC gradient MC gradient � Vacuum drying I => 0,2 % gradient max. � Vacuum drying II � Vacuum drying II => => 1 to 1,7 % 1 to 1 7 % � HF drying => -0,6 to -1,2 % Moisture content gradient 8% 7% 7% e content (%) 6% Vacuum drying I 5% Vacuum drying II 4% HF drying y g Moisture 3% 2% 1% 0% 0% Surface I Middle Surface II Drying / Sample

Results Casehardening – prong test Casehardening prong test � Vacuum drying I => 2,2 – 5,4 % � Vacuum drying II � Vacuum drying II => => 6 6 6,6 – 7 % 7 % � HF drying => 6,8 – 11,5 % 12% 10% ehardening (%) 8% 6% Case 4% 4% 2% 0% 1 2 1 2 1 2 3 4 Vacuum drying I Vacuum drying II HF drying Drying / Sample

Results Casehardening Casehardening – ENV 14464 ENV 14464 � Vacuum drying I => 0,5 – 1,2 mm � Vacuum drying II � Vacuum drying II => => 1 46 1,46 – 1,52 mm 1 52 mm � HF drying => 0 – - 2,8 mm 2 1,5 1 0 5 0,5 hardening (mm) 0 1 2 1 2 1 2 3 4 -0,5 Vacuum drying I Vacuum drying II HF drying -1 -1 Caseh -1,5 -2 -2,5 , -3 Drying / Sample

Results Internal stress (B N Ugolev method) Internal stress (B. N. Ugolev method) -4,0 -3,0 -2,0 (MPa) -1,0 Surface I Middle I Middle II Middle III Middle IV Surface II 0 0 0,0 Internal stress 1,0 Casehardening - ENV Casehardening - 2,0 Prong test 14464 ENV 14464 Prong test 3,0 4,0 8% 8% 1 5 1,5 5,0 1,5 8% 7% 6,0 7% 6% 6% Vacuum drying I 1 Vacuum drying I 2 1 5% Vacuum drying II 1 Vacuum drying II 2 5% 1 4% % 4% 4% 3% 3% 0,5 2% 2% 0,5 1% 1% 0% 0 0% 1 2 1 1 2 2 0 1 2 Vacuum drying II Vacuum drying I Vacuum drying II Vacuum drying I

Conclusion � quality results is depend on the method for measuring li l i d d h h d f i � Prong test � only reflects the stress condition in the surface layer � high stress gradients leads to strong deformation of the prong => indicating a low drying quality � slicing tests (as described in ENV 14464) g ( ) � is based on the internal stress difference between surface and core layers � more reflects an average stress level => indicating a better drying quality � the vacuum and the HF drying methods and the resulting drying � the vacuum and the HF drying methods and the resulting drying quality of dried material � the material dried in vacuum has lower moisture content gradient and smaller degree of casehardening ll d f h d i

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