Table 115 397 



SIZE AND CHARACTERISTICS OF AIR-BORNE SOLIDS 

 COMPILED BY W.G. FRANK 



LAWS OF SETTLING 



IN RELATION TO 



PARTICLE SIZE 



(Lines of Demarcation approx.) 



PARTICLES FALL WITH 

 INCREASING VELOCITY 



■v /ZHE 



3 V 3Ks t 

 C=24.9VDi; 



STOKES 

 LAW 



_2r*q S,-S 1 



FOR AIR AT 70° F 

 C = 300,460s,d 1 

 C =.00592 S.D 1 



CUNNINGHAM'S 

 FACTOR 



C=C'(l+K7-) 

 C'=Cof STOKES LAW 

 K=.8T0 .86 



C=Velocmj cm/sec 



C = Velocity ft./min 



d s Diam.of par- 

 ticle in cm. 



D^Diomof par- 

 ticle in Microns 



r= Radius of par- 

 ticle in cm. 



g=98lcm./sec> 

 acceleration 



S= Density of 

 particle 



S=Densitqof Air 



(Very Small 

 relative to s,) 



f]- Viscosity of 

 air in poises 

 =l8l4X|0* 7 for 

 air at 70° F. 



"X- I0" 5 cm. 

 (Mean free 

 path of qas 

 molecules') 



PARTICLES MOVE LIKE 

 OAS MOLECULES 



A= Distance of 

 motion in timet 



F3ROWNIAN' 

 MOVEMENT 



A =V /5I _Ll 



R= Gas constant 

 = 8.316 XIO 7 



T» Absolute 

 Temperature 



N =Numberof Gas 



molecules in 



one mol =6.06X10" 



>9ZI BY A/*£.QICAA 



> FILTEP COMPAN 



LOUISVILLE, HY COPYRIGHTED '9Z 



• FILTER. COMPANY INC LOUlSV 



IT IS ASSUMED THAT THE PARTICLES ARE OP UNIFORM SPHERICAL 

 THAT THE DUST CONCENTRATION IS 06 GRAINS PER 1000 cu. ft. of AIR. 



SHAPE HAVING SPECIFIC GRAVITY ONE AND 

 THE AVERAGE OF METROPOLITAN DISTRICTS. 



SMITHSONIAN METEOROLOGICAL TABLES 



