Agitator Calculation

Calcualtion of hp requirement n, N Da,

gaitator speed in rpm= Agitator speed in rps= Agitator diameter in metres =

p,

Density of liquid= Viscosity of liquid= viscosity in kg/ms = Reynold's number (p*N*Da2)/µ =

µ NRc Np, P

96 rpm 1.6 rps 0.65 m 1000 kg/m3 1 cP 0.001 kg/ms

Power number = Power in H.P.= (Np*p*N3*Da5)/(gc*75)=

Gland Losses 10% = Power Input= Transmission System Losses 20% = HP required= Fitting Losses,10% = Total HP required =

676000 1.6

(impeller is pitched blade)

1.033514 HP 0.103351 HP 1.136866 HP 0.227373 HP 1.364239 HP 0.136424 HP 1.500663 HP

Total power reqiored for 1 number of agiataor is

2 hp with 1440 rpm,FLP

GEAR bOX selection

Sf,

mechanical Service factor= Thermal Service factor for 40° = Larger of the two values = Required Ratio of gear box = The equivalent output torque = T= (4500*P*Sf)/(0.5*π*96)=

1.5 0.73 1.5 15 22.39252 kg-m

219.5956

the above torque value falls in V-287, 15:1 ratio gear box rating So the requird gear box size is V -287, ratio 15:1 and the motor of capacity 3 HP

Design calculation of Shaft djameter as per "EEUA", Appendix D P n

Nominal HP of Driving Motor= Agitator Speed= Type of agitator =

3 HP 96 rpm 45° pitched 4 numbers blades

fy

Yield Stress of shaft material in terms of apparent simple tensile stress =

fs

Safe working stress of shaft material in terms of apparent simple tensile stress= Material of construction = Length of agitator below bottom bearing= Overall diameterof agitator = Overall radius of agitator =

l D r

If Tc is the maximum continuous rated torque on the impeller shaft Tc =

(33000 *12*P)/(2* π*n*2240) = 0.879706 ton-inch

Jammed factor If Tm is the torque to be resisted under jammed condition Tm = 1.5*Tc = 1.319559 ton-inch This torque Tm is resisted bya force Fm tons acting at a ardius of 0.75r from the axis of impeller shaft Fm =

Tm /(0.75r) =

0.137505 ton

1 cP =

mpeller is pitched blade) gc=9.81 m/s2

p with 1440 rpm,FLP

N-m

capacity 3 HP

0.001kg/ms

ensile stress=

14 Ton/in2 8 Ton/in2 SA-479 GR-304 2500 mm 0.65 m 0.325 m

he axis of impeller shaft

12.79528 inches