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r <br /> BULLETIN N0. H-�1 <br /> VMOCITIES <br /> WITS THE DWrER PITOT TUSE <br /> AIR VELOCITY <br /> The total pressure of an air sir"in flowing in a dust is the suave of rho static or bursting pressure eserred <br /> oven tate sadew•iis of the duct Gail the Imposer or velocity pressure of the mowing air. Through the use of a <br /> Piro? tube wnnected daffereettaliy to a Manometer, the velocity pressure alone is Indicated and file car. <br /> responding air velocity determined. <br /> For accuracy of plus or minus Mas as in laboratory applications, extreme care is required and the Following <br /> precautions should be observed: <br /> 1 Duct daorneter A' or greater <br /> 2. Make an accurate traverse per sketem at 14 •�.., <br /> right, cotcuicte the vesocitees and civ. I = i , ,I <br /> a <br /> *rage the reacings. E _ <br /> rmn <br /> 3. Provtae smootn. straight ducx actions <br /> a eninimum or 8Y2 aiamwers in length <br /> upstream one ] 'h aiarnoters down- <br /> stream from rn• pilaf tube <br /> A Provide an egg crate type straightener <br /> upstream from the prrot tu". <br /> In making an air velocity crrcx stlect a location as suggested abovo, connect tuietaq lexis from beteh pilot <br /> 41• connoctiona re the caenent•ter and inserr in �e duct -nth the top are <br /> tcted into the air stream. If the <br /> exometer Shown a rnifteill Indlcorion reverse the tubes. With a direct reading neonornetor, ear veioeittes will <br /> naw► be s"w n to tsar pw minum. In other types, the raonowerer will retia velocity pressure on meas: of <br /> Water and th-P corresponeang v1®Erty will be foieno from the curves in thin bulletin. If circumstu aces & <br /> not meantl on accurate rraverso, center the pilot rube in the duct, detsrmene the center velocity one twilit. <br /> zly my a factor of 9 for rag approximate average veioe,ty. F1s1d tests rum in ?hes manner should be at- <br /> Curdle, <br /> c.Cur le, within Pius or ntanua S!L <br /> T ilv velocir/ indicated is for dry air at 7081F., 29.9" Barometric Pressure and a resulting d•nstty of 075:/ <br /> cu, k. For air at a teatperature wthor thole 70'F. rotor to the curves in ?itis aullletrn. For outer variations <br /> Prom these conditions, corrections may be basea oven the following doto: <br /> ave Velocity— 1096.2 �1 0 <br /> whole lev'"veloc,ty Pressure in indws of crater <br /> 0=Arr densely in :;/cu. ft <br /> Air Oansoey,::3 1 22.5 a r <br /> -bore Pt —8areonetne Pressure, in inches of Pmrcwry <br /> T—Ahisaiwat Temperature (indicatea romptratwe 'F <br /> plus A80 <br /> Flow on cu. Ft per lain. —Ouch area in Square feat it air vesKry in ft. <br /> per awut <br /> AIR VELOCITY STAIMLASS STEEL <br /> CALCULATOR 71 <br /> PITOT TUBES <br /> 0 .:a•wworrs ..locirw Wo" Tome a...onea wary co. <br /> w r• rNralrV co"OW0 0 cHic.r.•Rod WOOM O Mw. <br /> Nor cowr.rarws si noo"Mew srrwrren of eee.3" sreswp <br /> %we ewe t"aM.rr. Etwv« tows sr+do 1 mak green. <br /> Si Aw7�f r 1 a�Y i C O!C L� Q1$dWe Mer A1110111111 of ori.. <br /> M _ -wawa. trovea <br /> .neew (er two ver s i w f• <br /> in i <br /> 119 is 400 to 00 20.0PP11. ASMAC egeeJe�wwi <br /> '~ s. <br /> F-wMaRw mob wear poor L _ Sigel 12_ re 60 ' tows. <br /> „M <br /> s <br /> . r <br /> flMr w lad Mwrwr <br />