GB618854A - Improved process for seasoning timber - Google Patents

Abstract

618,854. Seasoning timber. KOBIOLKE, A. M. Nov. 24, 1943, No. 19614. [Class 140] Timber is stacked in open arrangement in a closed container 10, as by use of a trolley, and then subjected to the following treatments, (a) air is withdrawn through pipe 19 simultaneously with heating the interior of the container by circulating fluid through piping coils 16; (b) suction is maintained, the timber is immersed in water admitted through valve 20a, and this water is heated by steam admitted through inlet 24; (c) 'the vacuum, and the temperature of the water, are increased until the water boils turbulently; (d) the vacuum valve 19a is closed and air is admitted by valve 36 to raise the pressure to atmospheric, thereby causing the water to penetrate into the cells of the timber; (e) the air valve 36 is closed, the water further heated, air exhausted by reopening valve 19a and the water caused to boil turbulently until the tannic salts in the cells of the timber are diluted; (f) the vacuum is closed, the water drawn off and the vacuum valve re-opened, to cause the warm liquid remaining in the cells to boil turbulently; (g) the vacuum valve is closed and cooling fluid is circulated through the coils 16, whereupon vapour given off by the boiling liquid is condensed and the resulting liquid is withdrawn. Simultaneously fans 31, 32 are operated to circulate the vapour; (h) live steam is admitted to warm the timber; (i) the steam is shut off, the vacuum is restored and cooling fluid is passed through the coils and the vacuum is again restored to extract and convert moisture remaining in the timber into vapour and this vapour is circulated by the fans. Pre-heated air is then admitted through the valve 36, circulated in the container and discharged therefrom until the timber is dried to the desired condition; (k) the container is cooled by cooling fluid in the pipes 16 and, finally, the container is opened and the timber withdrawn. Steps (c), (d) and (e) to (h) may be repeated any desired number of times. The temperature in the interior of the timber is never allowed to get unduly high during the treatment, and it is ascertained by means of an indicating instrument 21 connected to a thermocouple 21a in a hole in one of the fletches of timber. The whole process takes many days.