ITALVIBRAS
98
Now determine the camber «f.»of the elastic system by means of diagram A, depending on the vibration frequency (rpm of
the electric vibrator) and considering a resonance ratio «r.» (between the vibration frequency of the vibrating complex and
the frequency of the elastic system itself) between 3 and 5.
The elastic constant of the anti-vibrating mount thus equals:
The capacity «
Q
kg
» and the elastic constant «
K
kg-mm
» are the two entities required to choose the anti-vibration mounts on
the market.
It is absolutely essential to distribute the load of the vibrating complex evenly over the elastic system.
Diagram B gives the percentage of elastic insulation (I%) between the vibrating structure and bearing structure, depen-
ding on ratio «r».
The anti-vibration mounts must be positioned so that the flexure is the same on all the elements, in order to balance the
machine.
Important
: the bearing structure to which the anti-vibration mounts of the vibrating complex are fastened must be rigidly
anchored to the ground or to some other type of bearing structure and always without any further anti-vibration ele-
ments.
where
f =
flexion of the elastic system (mm)
K
kg-mm
=
Pv
f
x
N
Type of process
Specific
weight
Sise
Vibrating
force
Vibrations per minute
Rotat.
Gericht.
600
(50Hz)
750
(50Hz)
1000
(50Hz)
1500
(50Hz)
3000
(50Hz)
6000
(50Hz)
9000
(50Hz)
720
(60Hz)
900
(60Hz)
1200
(60Hz)
1800
(60Hz)
3600
(60Hz)
-
-
nxg
Conveying
Separating
Sieving
Positioning
Grading
Sizing
Extracting
Feeding
F
•
•
•
4÷9
A
M
•
•
•
4÷6
G
•
•
•
3.5÷4.5
F
•
•
5÷7
B
M
•
•
4÷5.5
G
•
•
•
3.5÷5.5
Filter cleaning
A/B
F
•
•
•
2÷3
Slackening and emptying
material in silos, hoppers, etc.
A/B
F
•
•
A/B
M
•
•
Note (1)
A/B
G
•
•
•
Fluidized beds
•
•
•
2÷4
Separators (eg. for mills),
•
•
•
2÷4
Vibrating beds
F
•
•
M
•
•
•
G
•
•
0.7÷2
F
•
•
M
•
•
G
•
•
Compacting
F
•
•
•
•
•
M
•
•
•
•
•
2÷6
G
•
•
•
•
•
Compacting concrete
-
-
•
•
•
•
•
1÷2
Test benches (accelerated
ageing)
-
-
•
•
•
•
•
•
•
•
•
0.5÷24
Key:
Specific weight
A = high
B = low
Size
F = fine
G = coarse
M = medium
Note (1): Centrifugal force of the electric vibrator = 0.1 ÷ 0.25 for weight of material cpntained in the vibrating apparatus conic part.
Accelerat.
on the line
of force
a