Canadian wood products industries . ll carry so many pounds (or fractions ofa pound) of water vapor depending on the temperat- Table Giving Absorbing Power of Air Temperature Weight Water Vapor in one Cubic Foot of Air Fahrenheit Grains Pounds 50 .0006 60 .0008 70 .0011 80 .0016 90 .0021 100 .0028 110 .0037 120 .0049 130 .0063 140 .0081 150 .0102 160 .0128 170 .0160 180 .0197 190 .0241 200 .0293 From tables by Grosvenor and Goodenough7000 grains — 1 pound avoirdupois ure, and the air in the whole k
Canadian wood products industries . ll carry so many pounds (or fractions ofa pound) of water vapor depending on the temperat- Table Giving Absorbing Power of Air Temperature Weight Water Vapor in one Cubic Foot of Air Fahrenheit Grains Pounds 50 .0006 60 .0008 70 .0011 80 .0016 90 .0021 100 .0028 110 .0037 120 .0049 130 .0063 140 .0081 150 .0102 160 .0128 170 .0160 180 .0197 190 .0241 200 .0293 From tables by Grosvenor and Goodenough7000 grains — 1 pound avoirdupois ure, and the air in the whole kiln would hold a definitequantity. In order to remove any given amount ofwater (in the form of vapor) from the lumber in thekiln we would have to fill and empty the kiln withair a stated number of times. Moisture Absorbing Power of Air The application of the tabulation used in the operation of dry kilns requires the observance of suchvariables as temperature and humidity, but the pur- *Grand Rapids Vapor Kiln, Grand Rapids, D. Perry * pose of the above simile is to show the absolute neces-sity of a positive circulation of air in a dry kiln. Theabsorbing power of air varies with its temperature,from 4 grains per cubic foot at 50 degrees to 205grains at 200 degrees as shown by the accompanyingtable: The three important variables in dry kiln operationare circulation or ventilation, temperature or heat,and humidity. The third in a dry kiln is the humidityand it can be compared to the brake on a vehicle, be-cause it is the retarding element that prevents toorapid drying of the surface of the lumber and keepsthe surface of the lumber soft and plastic while moist-ure is coming out from the the boards. Natural Movement of Air It is not the purpose of this article, however, todiscuss the problems of heat and humidity, eventhough they are of sufficient importance enough towarrant it, but rather to emphasize the need of adequ-ate circulation. The short comings of most d
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectfurnitu, bookyear1922
