Forest Resources of Chile as a Basis for Industrial Expansion

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Forest Service, U.S. Department of Agriculture, 1946 - 256 páginas
 

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Página 235 - Truckloads of green stock are periodically fed into the kiln and truckloads of dried stock removed at the same time from the other end of the line. The stock thus moves progressively through the kiln until it emerges, supposedly dry, after a specified time of exposure to the various conditions along the length of the kiln. The temperature and...
Página 235 - The temperature and relative humidity at any point are intended to remain constant, but the kiln is hotter and drier at the dry end than at the green end. The compartment kiln is loaded fully at one time, the entire charge remaining in place throughout the drying period. The temperature and relative humidity are as nearly uniform as possible throughout the kiln at any given time.
Página 223 - ... Principles of Bending Wood of certain species steamed or soaked in boiling water can be compressed as much as 25 to 30 percent parallel to the grain. The same wood can be stretched only 1 to 2 percent. Because of the relation between attainable tensile and compressive deformations, it is necessary, if bending involves severe deformation, that most of the deformation be forced to take place as compression. The inner or concave side must assume the maximum amount of compression and the outer or...
Página 235 - ... kiln. In the compartment class, on the other hand, the kiln is loaded fully at one time, the entire charge remaining in place throughout the drying period. Again, in the progressive kiln, the temperature and humidity at any...
Página 237 - ... appearance. Although the various presses differ greatly in the details of their construction, most of them work on the cylinder-and-plunger principle, the plunger being driven by means of crank and connecting rod or by some toggle-joint system of levers so designed that it is capable of exerting a very great pressure at the end of the stroke. Practically all of them also are automatically fed. In systems in which binders such as pitch are used and in those in which the resins of the wood serve...
Página 237 - ... wood should be considered entitled to a reasonable profit on the costs of his operation. Some of the " war fuel companies " which were formed during the fuel crisis in the winter of 1917-18 limited their profits to 6 per cent. Municipal yards as a rule sell at cost. MANUFACTURE OF SAWDUST BRIQUETS.1 Practically all of the European machines use some kind of binder mixed with the sawdust, or rely upon the resinous material in the wood to hold the briquet together, but American and Canadian inventors...
Página 237 - Hu. 15, 1016. 10 per cent. These briquets are hard and firm and resemble coal briquets in general appearance. Although the various presses differ greatly in the details of their construction, most of them work on the cylinder-and-plunger principle, the plunger being driven by means of crank and connecting rod or by some toggle-joint system of levers so designed that it is capable of exerting a very great pressure at the end of the stroke. Practically all of them also are automatically fed. In systems...
Página xi - ... is: (1) To make an inventory of the extent and condition of forest lands and of the present supply of timber and other forest products on these lands; (2) to ascertain the rate at which this supply is being increased through growth, and the potential growth on forest areas; (3) to determine the extent of depletion of the forests through cutting and through loss from fire, insects, disease, windthrow, and other causes; (4) to determine the present consumption and the probable future trend in requirements...
Página 108 - When possible, it is good practice to season the stock in the board or plank form before working up into dimension stock. The handling costs are also materially greater than for an equal footage of material in board form. The requirements of the various consumers may mean a considerable number of standard sizes would be required. Production efficiency and quick handling of stock may mean that the number of sizes produced should be kept at a minimum, and that only standard items in greatest demand...
Página 168 - MATHEWSON, JS 1930. THE AIR SEASONING OF WOOD. US Dept. Agr. Tech. Bull. 174, 56 pp., illus. STIMSON, B. 1928. THE ECONOMY OF FRAMING STRUCTURAL TIMBERS BEFORE TREATMENT. Amer. Wood Preservers

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