cold milk skimming separator

Separatorion of Milk
Hot vs. Cold

Separator principes
warm milk separator
MSE 500-01-777
standard design
cold milk separator
MSE 500-48-777
hermetic design
GEA Mechanical Equipment / GEA Westfalia Separator

Comparison Cold Milk and Hot Milk Skimming
hot milk skimming separator
feed from above
discharge via double
centripetal pump (static)
hydrohermetic sealing
cold milk skimming separator
cold milk skimming separator
feed from below
discharge via double
pumping wheel (rotating)
mechanical seals
GEA Mechanical Equipment / GEA Westfalia Separator

Hot Skimming Bowl
centripetal pump for skim
centripetal pump for cream
rising channel
feed tube
separating disk
distributor
bowl top
disk stack
distributor
channel
sediment
holding
space
ejection port
sliding
piston
bowl
bottom
GEA Mechanical Equipment / GEA Westfalia Separator

Flow in Hot Skimming Bowl
whole milk
cream
skim milk
solids
GEA Mechanical Equipment / GEA Westfalia Separator

Hermetic Skimming Bowl
cream pump
skim pump
rising channel
separating disk
bowl top
disk stack
distributor
channel
sediment
holding
space
distributor
ejection port
feed bore in spindle
sliding
piston
bowl
bottom
GEA Mechanical Equipment / GEA Westfalia Separator

Flow in Hermetic Skimming Bowl
whole milk
cream
skim milk
solids
GEA Mechanical Equipment / GEA Westfalia Separator

Cold Milk Skimming
Usually milk is skimmed during pasteurisation at 50°C – 55°C.
However in some cases it is done at low temperatures:
For the production
no pasteurisation is
is necessary
of raw milk type cheeses
allowed, so cold milk skimming
to standardise the fat content
For the production of high quality products – i.e.
low heat milk powder - cold milk skimming is applied
to avoid double heating
A significant energy saving will be achieved if a double heating
is avoided.
The main markets for cold milk skimming are Australia, New Zealand,
Mexico and USA.
Mostly temperatures are between 4°C and 8°C, but in general terms
anything below 20°C is regarded as cold milk separation.
GEA Mechanical Equipment / GEA Westfalia Separator

Cold Milk Skimming
Cold milk skimming differs from hot milk separation in a number of ways.
The milk viscosity is
separation velocity of
higher at low temperatures, so the
the fat globules is reduced.
The cream viscosity
is much higher at these low temperatures,
this imposes the risk of internal blockage of the bowl.
Therefore the maximum cream fat is limited to 42%.
Cold milk skimming separators are designed as
semi-hermetic
or hermetic machines, the supply from below allows
a central cream discharge with big cross sections.
Cold milk skimming has a higher demand of clarifying surface, equivalent
machines handle smaller capacities than for hot milk skimming.
The skimming efficiency is very dependent on temperature and capacity,
values of 0,1% to 0,4% are realistic.
Most of the milk fat fractions are crystallised at low temperatures, so the fat
globules are much more fragile and sensitive to shearing stress.
GEA Mechanical Equipment / GEA Westfalia Separator

Reasons for cold separation
10
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Cold Milk Skimming Plant with Preheater
GEA Mechanical Equipment / GEA Westfalia Separator

Cold Milk Skimming Separator Characteristics
skim fat
1,3 %
1,2 %
5°C
1,1 %
1,0 %
0,9 %
10°C
0,8 %
0,7 %
15°C
0,6 %
0,5 %
20°C
0,4 %
0,3 %
0,2 %
0,1 %
0,0 %
0 l/h l/h
feed rate
5.000 5.000 l/h l/h
10.000 10.000 l/h l/h
15.000 15.000 l/h l/h
20.000 20.000 l/h l/h
25.000 25.000 l/h l/h
30.000 30.000 l/h l/h
35.000 35.000 l/h l/h
40.000 40.000 l/h l/h
45.000 45.000 l/h l/h
50.000 50.000 l/h l/h
MSE 140-48
48-177
MSE 500-48
48-777
GEA Mechanical Equipment / GEA Westfalia Separator

Evolution of Feed Systems
1968 1978 2008
Rib Distributor System
Soft Stream System
Hydro Soft System
Milk
separators
Hermetic System
Coldmilk
separators
GEA Mechanical Equipment / GEA Westfalia Separator

Efficiency of Feed Systems
1968 1978 2008
warm milk
separators
Rib Distributor
SAMM / MSA- types
- risc of shearing
+ flexible capacity
+ low feed pressure
Soft Stream System
MSD- types
+ no shearing
- Limited capacity
+ low feed pressure
Hydro Soft System
MSE- types
+ no shearing
+ flexible capacity
+ low feed pressure
cold milk
separators
Hermetic System
MSA / MSE- types
+ no shearing
+ flexible capacity
- high feed pressure
GEA Mechanical Equipment / GEA Westfalia Separator

Cream Concentration
Relation of skimming efficiency and cream concentration
Cream
concentration
up to 45 %
Cream
concentration
> 45 %
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Feed systems
16
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Hermetic Seals
17
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Function of Centripetal Pumps
Principle
GEA Mechanical Equipment / GEA Westfalia Separator

GEA Westfalia Separator hydrosoft
No mechanical seal
necessary between static
inlet pipe and rotating
distributor. No cooling
water required.
The end of the inlet
pipe is continuous
below the liquid
surface, that is why
there is no air intake.
There are no
cross braces, that
is why there is no
shearing.
The plate which is near
to the outer wall, keeps
the liquid in the room
under the inlet pipe.
1
BL Dairy Technology
GEA Mechanical Equipment / GEA Westfalia Separator

GEA Westfalia Separator hydrosoft
There are 12 holes for
the liquid to feed the
disc stack:
•even distribution
•directed flow, no
turbulences
•low flow speed
The system
enables to
handle different
flow rates, it is
not limited by
the construction
Because of the
low flow rate,
there is low
shearing and
low pressure
Low feed
pressure,
because there
is a suction
effect
2
BL Dairy Technology
GEA Mechanical Equipment / GEA Westfalia Separator

GEA Westfalia Separator hydrosoft
Features and advantages leading to customer benefits!
•without mechanical seal
• no cooling water required
reduced maintenance cost
savings in operational costs
•no shearing, no air intake premium product quality
•flexible capacity
easy process implementation
•low feed pressure < 1 bar no extra booster pump required
savings in energy
savings in installation and
maintenance
2
BL Dairy Technology
GEA Mechanical Equipment / GEA Westfalia Separator

Electrical Power Consumption
milk pasteurizing
line with
standard separator
(warm milk)
GEA Mechanical Equipment / GEA Westfalia Separator

Electrical Power Consumption
milk pasteurizing
line with
hermetic separator
(cold milk)
GEA Mechanical Equipment / GEA Westfalia Separator

Milk Pasteuriser
typical installation:
skimming separator in a milk pasteuriser, upstream
TIRA
SKIM MILK
MILK
TIC
FIC
CREAM
F
P
GEA Mechanical Equipment / GEA Westfalia Separator

Electrical Power Consumption Savings (i.e. UHT
Milk and cold separation)
milk pasteurizing
line with
standard separator
(warm milk)
GEA Mechanical Equipment / GEA Westfalia Separator

Electrical Power Consumption Savings UHT Milk
approx. 15 - 20m³/h
Heating from
5-72-5°C
Item: Dimension in € approx. Amount/h Amount /a
Electrical Energy: 25 - 25 kW/h 0,09 ct/kwh 2,25 15750
Steam: 200 kg/h 23,50 €/t 4,7 33000
Water: 25 m³/h 1,5 €/m³ 37,5 262000***
press. Air: 10 m³/h 0,015€/m³ 0,15 1050
GEA Mechanical Equipment / GEA Westfalia Separator

Some like it cold!
Capacity
Skimming efficiency
Microbiology
Operating life
Gentle product treatment
Logistics / flexibility
Energy consumption
Service friendliness
Warm Milk
Cold Milk
+ -
+ -
- +
+ +
- +
+ +
- +
+ -
GEA Mechanical Equipment / GEA Westfalia Separator