1. VRM
mkpasha_sitelcl@hotmail.com

2. 1. Separation →
2. Grinding →
3. Drive →
Separation
Feed
Material
Grinding
Drive
Raw meal
Exhaust gases
Transport
Drying
gases
Energy
Hot
8/7/2013

3. feed gate
(air lock)
mill casing
water
injection
dam ring
louvre ring
nozzle of
material scraper
mill outlet duct
speed reducer with
table bearingand motor
clutch
grinding table
hot gas inlet
hydraulic cylinder
table liner
roller with tyre
or segments
roller axle
rocker arm
discharge flap
separator
tailings cone
separator
guide vanes
cage rotor
separator
product discharge
mill exhaust
8/7/2013

4. 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

5. 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

6. G.Pfeiffer Loesche FLS Atox Polysius
8/7/2013

7. static separator conventional rotor type cage rotor type
with 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

8. Angle affects
product sizing
Rotor speed affects
product fineness
Rotor seal affects
separator efficiency
8/7/2013

9. 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

10. 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

11. Control points
1 gas flow
2 pressure
difference
3 return gas flow
pressure
4 outlet
temperature
5 external
recirculation
8/7/2013

12. 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