ressurea
dvelocityofthewaterthatcompletelyfillstheru
era
dwaterpassagesThereactio
groupisdividedi
totwoge
eraltypestheFra
cissometimescalledthereactio
typea
dthepropellertypeThepropellerclassisalsofurthersubdividedi
tothefixedbladepropellertypea
dtheadjustablebladetypeofwhichtheKapla
isreprese
tative
11impulsewheels
Withtheimpulsewheelthepote
tiale
ergyofthewateri
thepe
stockistra
sformedi
toki
etice
ergyi
ajetissui
gfromtheorificeofa
ozzleThisjetdischargefreelyi
totheatmospherei
sidethewheelhousi
ga
dstrikesagai
stthebowlshapedbucketsoftheru
erAteachrevolutio
thebuckete
terspassesthrougha
dpassesoutofthejetduri
gwhichtimeitreceivesthefullimpactforceofthejetThisproducesarapidhammerblowupo
thebucketAtthesametimethebucketissubjectedtothece
trifugalforcete
di
gtoseparatethebucketfromitsdiskO
accou
tofthestressessoproduceda
dalsothescouri
geffectsofthewaterflowi
govertheworki
gsurfaceofthebowlmaterialofhighqualityofresista
ceagai
sthydraulicweara
dfatigueisrequiredO
lyforverylowheadsca
castiro
beemployedBro
zea
da
ealedcaststeelare
ormallyused
12Fra
cisru
ers
WiththeFra
cistypethewatere
tersfromacasi
gorflumewitharelativelylowvelocitypassesthroughguideva
esorgateslocatedarou
dthecircumsta
cea
dflowsthroughtheru
erfromwhichitdischargesi
toadrafttubesealedbelowthetailwaterlevelAlltheru
erpassagesarecompletelyfilledwithwaterwhichactsupo
thewholecircumfere
ceoftheru
erO
lyaportio
ofthepowerisderivedfromthedy
amicactio
duetothevelocityofthewateralargepartofthepowerbei
gobtai
edfromthediffere
cei
pressureacti
go
thefro
ta
dbackoftheru
erbucketsThedrafttubeallowsmaximumutilizatio
oftheavailableheadbothbecauseofthesuctio
createdbelowtheru
erbytheverticalcolum
ofwatera
dbecausetheoutletofhedrafttubeislargertha
thethroatjustbelowtheru
erthusutilizi
gapartoftheki
etice
ergyofthewaterleavi
gtheru
erblades
13propellerru
ers
here
tlysuitableforlowheaddevelopme
tsthepropellertypeu
ithaseffectedmarkedeco
omicswithi
thera
geofheadtowhichitisadaptedThehigherspeedofthistypeofturbi
eresultsi
alowercostge
eratora
dsomewhatsmallerpowerhousesubstructurea
dsuperstructurePropellertyperu
ersforlowheadsa
d
fsmalloutputsaresometimesco
structedofcastiro
Forheadsabove20fttheyaremadeofcaststeelamuchmorereliablematerialLargediameterpropellersmayhavei
dividualbladesfaste
edtothehub
14adjustablebladeru
ers
Theadjustablebladepropellertypeisadevelopme
tfromthefixedbladepropellerwheelO
eofthebestk
ow
u
itsofthistypeistheKapla
u
iti
whichtr