liquid mixing

Question 1

2 requirements of mixing

Answer 1

shear and flow ( general movement )

Question 2

longitudinal radial and tangential

Answer 2

excessive tangential facing forward- vortex -air
excessive radial - materials to vessel wall
insufficient longitudinal - stratification

Question 3

propeller
turbine vs
paddle

Answer 3

propeller - high longitudinal

tubine - strong radial
weak tangential

paddle - strong radial
- strong tangential

Question 4

3 impeller positions

Answer 4

offset, angled and side entering

Question 5

func of baffles

Answer 5

• prevent vortexing

Question 6

what is D/d and its result

Answer 6

vessel diameter over impeller diameter
low viscosity - high speed rotation with high D/d ( smaller impeller )
high viscosity - low speed - low D/d
( larger imepller )

think of like dough

Question 7

which mixer for low viscosity

Answer 7

propeller , not for emulsification or high viscosity

Question 8

turbine mixer for

Answer 8

emulsification
high viscosity
liquids that may stratify
( if stratification occurs with propller mixer then use this )

Question 9

if paddle mixer used at high speed then need what

Answer 9

baffles to prevent swirling and vortexing

Question 10

what kind of paddles for high and low viscosity

Answer 10

high viscosity - paddle shld fit closey to the vessel wall
if super high then - smaller paddle rotating on tis own axis while travelling in circular path ( think of baking mixer )
if low viscosity - paddle shld be plain

Question 11

how to avodi vortexing and aeration

Answer 11

impeller moutned deep in fluid
offset position of impeller
employ push pull propeller - 2 blades
baffles on side of vessel wall