12
1. Separation
2. Grinding
3. Drive
Separation
FeedMaterial
Grinding
Drive
Raw mealExhaust gases
Transport
Drying
gases
Energy
Hot
8/7/2013
feed gate(air lock)
mill casing
waterinjection
dam ring
louvre ringnozzle of
material scraper
mill outlet duct
speed reducer withtable bearingand motor
clutch
grinding table
hot gas inlet
hydraulic cylinder
table liner
roller with tyreor segments
roller axlerocker arm
discharge flapseparator
tailings cone
separatorguide vanes
cage rotorseparator
product dischargemill exhaust
8/7/2013
Vertical roller mill
Feed size:f (Roller Ø )
Material bed
Feed material
Max Particle size in feed: 5-8 % of roller diameter
Grinding force =
Roller weight + (pressure) Force
Table moves with drive
Roller rolls freely with table
8/7/2013
Gas & Product Material
Feed Material
Separator Rejects
Internal Circulation
Large Material falls through to scraper
Internal gas flow
Material & Gas
Material
Gas
Separator:
removes fine material
rejects coarse material
8/7/2013
G.Pfeiffer Loesche FLS Atox Polysius
8/7/2013
static separator conventional rotor type cage rotor typewith guide vanes
F T
P
F F FT T
P
F F
T
P
T F
P
F =
P =
T = Tailings
Product
Feed
F T
Cage Rotor typeConventional
Rotor type
Static type
Separation control:
1. Vane adjustment
2. Speed control
8/7/2013
Angle affects product sizing
Rotor speed affects product fineness
Rotor seal affects separator efficiency
8/7/2013
Used for reducing gas flow pressure lost over the mill
(less pneumatic internal circulation)
collecting conveyor
fresh feed
louvre ring
scraper
bucket elevator
8/7/2013
Control
Gearbox - Vibration monitor
- Temperature monitor
Gas flow - Temperatures & pressures
Hydraulics - Pressures
Maintenance
Wear - Rollers & Table
- Separator (sealing!) & Housing
Lubrication & Hydraulics (filters and seals)
8/7/2013
Control points
1 gas flow
2 pressure
difference
3 return gas flow
pressure
4 outlet
temperature
5 external
recirculation
8/7/2013
Rotary valve Pendulum valve
Weigh belt Metal extraction
Reduces false air entering with feed material. Good for dry, small size material.
Reduces false air entering. Better for lumpy or humid feed material.
Weighs the passing material ensuring a continuous grinding bed in the mill
Metal objects damage the roller & table. The magnet removes them
8/7/2013
