The effect of rate of pressure application on preservative uptake along and across the grain of fir (Abies bornmulleriana Mattf.) at different ramp and constant pressure times
This study was particularly design to determine the preservative uptake at different ramp (rate of increase in pressure) and constant pressure times on longitudinal, tangential and radial penetrations of fir (Abies bornmulleriana Mattf.) which grown indigeneously in Turkey. The samples of 2 cm cubes of kiln-dried wood (nominated to 12% moisture content) were treated at different ramp times varied from very fast to very slow rates of pressure (bar) per time (seconds) at 5, 15, 30, 60, and 90 sec. and the maximum pressure of 4 bars -in the treating vessel to refusal- was applied at the constant pressure time for 5 min.
The preservative uptake was determined as the percentage of void volume filled (VVF%) for either flow directions at each ramp time. The results showed that the VVF% was, as expected, markedly greater in the longitudinal flow direction than both in the tangential and radial flow directions. In comparison to the VVF% laterally, it was greater in tangential direction than in radial direction in either treatment schedules. In this issue, although the trend seemed to be the similar between the flow directions, quite different patterns were observed within each direction for penetration and ramp times. Accordingly, conclusions were listed separately for each flow direction.
Keywords: Full-cell process, pressure rate, preservative uptake, refractory softwood, fir