FOR DRYING LUMBER.

Dunstan Times, Issue 3148, 18 December 1922, Page 2

FOR DRYING LUMBER.

Advice of an interesting now process lor the natural air drying of limber has been received by the Forestry Department. This process has' recently come to the front in Canada and in it a standard type of machine which accommodates li) 00 feet of timber at one loading is used. The method consists of spinning the stock at eighty revolutions per minute and the intense suction opens the cells of the wood and removes the moisture. The time required for loading, spinning, and unloading the lumber is about two hours. Green logs of birch and pipe have been hauled out of an Ontario Lake, where they had lain for several weeks, cut up in the mill and spun in the machine, after which they were allowed to stand in the open for a week. The result was that the timber was reduced in weight by :il per cent., or as against the dry lumber o2 pel' cent, of moisture was removed. The principle of the operation, so far as can be ascertained, is as follows: There is a (5-inch framework on the upper and lower sides, cadi capable ol holding 20D0 feet of timber. The lumber is piled front the sorting table on lo a buggv or truck u ith the usual 1-inch stripping, and with 2000 feet is run into the upper frame of the machine, and is securely locked in. then turned over, and a similar truck load is placed in the lower half of the machine. This also is locked and power is turned on to revolve it. The machine revolves at the rate of eighty times per minute, the intakes being so adjusted Unit air into it at the rate of forty miles an hour, creates a. vacuum, and comes out. at tlimrate'ol" eighty miles an hour as proved by actual test. This intense pull or suction apparently opens the eels of (be wood and sets up a sypbon-like action, and once this action commences the trucks are taken out and side tracked and the lumber allowed to stand .the moisture continuing to come out until at the end of the week it -bows the difference in weight mentioned. It. shows no signs of cracking or warping, am! some of the birch has

been used with excellent results and without having to resort to a dry kiln. The power necessary to operate the machine is eight to ten horse-power. The other agent is free air, no heat being required. This machine can be loaded five times per ten-hour day. thus giving 20,000 feet at the end of one week -,and that quantity of dry lumber daily thereafter during the operation of the drying plant. Some timber has been dried out with the thermometer at 30 degrees below zero.