FRITSCH PULVERISETTE 4 classic line - Manual (Page 28)

6.1.3 Calculated weight of a ball
Ball diameter in mm 5 10 15 20 30 40
Material Density
in g/cm 3
Calculated weight of a ball in g
Agate 2,65 0,17 1,39 4,68 11,1 37,46 88,8
Silicon nitride 3,25 0,21 1,7 5,74 13,61 45,94 108,91
Sintered
corundum
3,9 0,25 2,04 6,89 16,33 55,13 130,69
Zirconium
oxide
5,7 0,37 2,99 10,07 23,88 80,58 191,01
Stainless steel 7,8 0,51 4,08 13,78 32,67 110,27 261,38
Tempered steel 7,9 0,52 4,13 13,96 33,09 111,68 264,73
Tungsten car-
bide
14,9 0,97 7,8 26,33 62,41 210,64 499,3
To determine the weight of the required balls, the "calculated weight of
a ball" is multiplied by the "number" of balls required.
Example: A 250 ml agate bowl is to be filled with 1221 agate balls with a
diameter of 5 mm.
Calculation: 0.17g * 1221 St » 208 g
208 g of grinding balls can be weighed and inserted in the grinding bowl,
thus avoiding the time required for counting the balls.
6.2 Filling quantities of grinding bowls
CAUTION!
For wet grinding with large balls with a diameter of >10
mm, at least half the maximum sample quantity must be
inserted. If the suspension is highly fluid, the balls will not
have any resistance and the balls and the grinding bowl
could be damaged. The result is the same as if it had been
filled with no grinding stock. The same applies to dry
grinding with less than the minimum sample quantity.
NOTICE!
Never operate the mill without grinding stock! This can lead
to grinding balls and grinding bowls getting damaged.
Using the device
- 28 -