Document bazxmMOzEMneL22LL9nnKobM0

V American Society of Heating and Ventilating Engineers Guide, 1932 Table 1. Size of Connections for Wood-Working Machinery Type of Machine Diameter of Connections in Inches Circular Saws, 12-24-in. Hiam. .......... Circular Saws, 24-40-in. Hiam. Band Saws, Blade under 2 in. wide ___ Band Saws, Blade 2-3 in. wide ............... Band Saws, Blade 3-4 in. wide ...... ..... Band Saws, Rlade 4-5 in. wide ... Band Saws, Blade 5-6 in. wide........ .................................. ... ................................... Single End Tenoners............ .......................... Double End, Double Head Tenoners___________________ ,_______ ____________ Planers, Matchers, Moulders, Stickers, Jointers, etc.-- With Knives, 6-10 in______ . ...................................................................... With Knives, 10-20 in................... ............................................. ............................ With Knives, 20-30 in.______________ ___ Shapers, T.igHt Work Belt Sander, Belt less than 6 in. wide Belt Sander, Relt 6-10 in. wide Belt Sander, Relt 10-14 in. wide Drum Sander, 24 in____ . .... ............................................. ......... .... Drum Sander, 30 in......... Drum Sander, 36 in.. _ .... .-......... ............... .............. .............................. Drum Sander, 48 in. . Drum Sander, over 48 in.............................. Disc Sander, 24 in. diam............. ..... .. Disc Sander, 26-36 in. diam. .< Disc Sander, 36-48 in. diam_______________ __________________________________ 4 5 6 4 5 6 7 8 6 6 7 10 5-6 6-8 6-10 4-5 8 5 6 7 5 6 7 8 10 5 6 .7 4 Table 2. Size of Connections for Grinding and Buffing Wheels Diameter df Wheels Grinding-- 6 in. or less, not over 1 in. thick._____ 7 in. to 9 in., inclusive , not over l\4 in. thick____ 10 in. to 16 in., * a a 2 in. " ____ 17 in. to 19 in., 20 in. to 24 in., " * " 3 in. " " . " 4 in. 25 in. to 30 in., B " 5 in. " ____ Buffing-- 6 in. or less, not over 1 in. thick. ____ 7 in. to 12 in., inclusive, not over 114 in. thick____ 13 in. to 16 in., " a 2 in. " ____ 17 in. to 20 in., " " " 3 in. a ....... 21 in. to 27 in., " " .4 in. " 27 in. to 33 in., a " " 5 in. c ____ Max. Grinding Surface Sq. In. 19 43 101 180 302 472 19 57 101 189 338 518 Min. Diam. of Branch Pipes in Inches 3 3\4 4 4H 5 6 ' 3}4 4 m 5 6' 7 348 Chapter 25--Ventilation of Industrial Buildings; Exhaust Systems Certain materials such as grease wools, silk waste, salt, and other hydro scopic substances are difficult to handle due to the tendency to deposit in die conveyor pipes. While the velocity in the system should be sufficiently high to insure the removal of the material, it should be kept as low as practicable since any higher velocity requires the use of unnecessary power. With a fixed system or orifice the power increases as the cube of the increase in velocity; or for the same quantity of air and material handled, inversely as the fifth power of the diameter of round ducts. Velocities commonly employed are: 2,500 to 3,000 fpm for light dusts, cotton, shavings and sawdust from dry wood, and similar substances. Heavy dusts, wool, shavings and sawdust from wet wood, rags, waste Table 3. Suction Pressures Required at Hoods for Connections of Usual Proportions Static Suction in Inches or Water Exhausting from wood-working machinery--heavy duty------------------------- Fur and felt machinery exhaust.___ -............-- ....................................... Conveying bulky and heavy materials................. ............................;--.............. 2 2 2 2-4 2-3 2 2 2 2--4 2-3 2-3 2 3-5 ' paper and similar materials, 3,000 to 4,000 fpm. Lead dust, hog waste, pulp chips, etc., 4,000 to 6,000 fpm. In choosing the pipe sizes consideration must be given to the manner in which the machines will be operated, as in case a considerable number of machines, all discharging into one main, should be shut off at the same time, the velocity in the main might easily be lowered to the point where it would not be sufficient to carry the material from the machines still in operation, and thus result in clogging the pipes. Accordingly, it is sometimes desirable to use velocities higher than the minimum to allow a factor of safety to cover this contingency. In some states codes have been issued specifying suctions to be main tained for the more common dusts. A suction standard should always be considered in conjunction with the shape of hood, and size connection, as these factors together determine the volume of air exhausted and its velocity, which in turn are a measure of the effectiveness of the exhaust system. 349