Document Lovq1y289J6QGmjogz0m9DwMg

1 ; i! ii American Society of Heating and Ventilating Engineers Guide, 1929 . Table 2. Air Duct Velocities for Forced Draft Static Pressures 2 2A 3 3A. 4 4H 5 m 6 6a. 7 Velocitt in Main Am Duct 5 Peb Cent Static Pressure 1300 1400 1550 1700 1800 1900 2000 2100. 2200 2300 2400 Velocitt in Main Am Duct 10 Per Cent Static Pressure 1800 2000 2200 2400 2550 2700 2850 3000 3100 3250 3350 From Recommendations for the Installation of Stoker Fans by the Stoker and Fan Manufacturers' Association: The area of the main air ducts shall be determined by using a velocity in the ducts based on a velocity pressure of from 5 per cent to a maximum of 10 per cent of the static pressure. The area of the branch air ducts leading to boilers should be such that the velocity will not be more than two-thirds of that in the main ducts. The above table is based on a weight of air of 0.075 lb. per cu. ft. which corresponds to a temperature of 6S deg. fahr., a barometric pressure 29.92 in. (sea level) and 50 per cent relative humidity. (For higher elevations or temperatures, the above velocities may be increased 1 per cent for each 500 ft. increase in elevation, add 1 per cent for each 10 deg. fahr. increase in temperature.) It is desirable to have the duct work as short and straight as possible and for the class of installations contemplated under this heading 2500 ft. per minute is a satisfactory velocity for the air through the duct work as a maximum. Table 3. For Forced Draft Blowers Based on 40 cu. ft. of air per minute per square foot of grate Crate Area 8q. Ft. 4 6 10 12 16 20 24 30 36 40 No. 1 Buckwheat Coal Size of Blower Outlet In. C.f.m. Static Press. In. Motor Speed Hp, R.p.m. 4 160 0.25 Ms 1750 6 240 0.51 A 1150 6 400 0.75 A 1750 6 480 0:68 A 1750 8 700 0.76 A 1750 9 800 0.91 A 1750 9 960 0:65 Yi. 1750 9 1200 0.93 A 1750 11 1440 0.72 A 1150 9 1600 . 1:2 m 1750 No. 2 and 3 Buckwheat Coal Size of Blower Outlet In. CXra. Press. In. Motor Speed Hp. R.p.m. ___L.. __ ____ ' 8 400 1.14 A 1750 9 550 1.23 A 1750 9 700 1.04 y?. 1750 8 800 1.25 a 1750 9 960 1.22 A 1750 12 1300 1.25 A 1150 _____ . 9 1600 1.22 1A 1750 Table 4. Capacities and Dimensions of Propeller Type Forced Draft Blowers Outside Duustsm or Fan " Houpsre Iwiyea 12 14 16 18 21 24 27 Motor H.P. A Vi At % 1 1A 2 0.10' 1100 1600 2550 3300 4350 6300 8400 0.1S' 1050 1550 2450 3250 4250 6200 8300 Cubic Feet per Minute at Various Static Pressures 0.20* 950 1500 2350 3200 4150 6100 8200 .0.25' 850 1450 2250 3150 4050 6000 8100 0.50' 300 750 1450 2800 3500 5500 7500 0.75' 450 1100 2300 2750 4900 6800 1,00' _ 800 1500 2000 4100 6100 164 T a b l e 5. . C a p a c it ie s an d D im en sio n s of Ste a m T u r b in e D r iv e n Pr o peller T ype F orced D r aft F ans snippy VIIChapter --Mechanical Draft ^C'J i tO 80'oOQOOOO'OOQQOOiOo'Ofl'OOCC 888888883888888888888 N(N'OM-Hi/)f(00'OoICmO^N>0o0<Oo`rO'^oNoO'O'O00coOr'O00'f^',O''OQoOo> ?888< 8888888S i>O*oOQOOOnO*oOooQoOu-O>Oo l3,v'OOOO'ONOOr'OoOo^r*'C`OS^'OOKVO) OOOOQOOQQOQOOOOQOOQQOQ iOOQ LOO to to QQn0tototo .li olOoQoQoiOiOQ'OVjioQO<' Nro^O^t'O'O'OiOCC'Oi 2>5ACt--i'JotO#ivn'IOOooOto*OoolCooACoMCoLNoOfOoOOoO,\oOrcC-ii 88888888888888888S8S88 00t--e^^v-toot---csv-<r4tO'OQO'Oooro-'ONC,s| csrO^'OtO'tot-- v OO t-- \*--\00O\CS^t-- t-- t-I toto 00 to Os Cc'Z.____tO_o' tc^o motcoosf^--^*Ocovot--otoo\t--o\toooto^<oio-m_i^ro_--voo <Nfo^'Otot--tor-- > ` < >,V) to to toot-- totO*0*OtOtO10C 3 o< C<O to t-- so' Tt--p t'Oo foootor-to--sooQtPCoS\^^OOeO^O^OtO--CoNo-<* 8888888888888888888888 58888888,____________ _______________ jOlO`OOOtN*^'0'0`OtO*-'Of*3*HOvlCNNWC<'u F'lOCo^fOTfrO'effOT^rOr^cO^rocOfOTj'rorororO o5gB3gsS<o^p*> 5Dq^tPSa5 165 X