Vibratory Feeders
5
The following general rules, which apply only to the
Feeder operating ideally on the “normal” side of its
“tuning curve,” should be borne in mind when making
tuning adjustments to increase or decrease the
displacement:
1. 1. To DECREASE the tray displacement,
INCREASE the stiffness of the tuning springs.
2. 2. To INCREASE the tray displacement,
DECREASE the stiffness of the tuning springs.
If decreasing or increasing the tuning spring stiffness has
an opposite effect, it means that the spring stiffness is
great enough that the unit is operating on the “opposite”
side of its tuning curve. The spring stiffness should be
increased until the behavior is in accordance with rules 1
and 2. The unit can then be properly tuned to the desired
displacement.
As a guide to the stiffness of individual tuning springs,
each spring is marked with a code number example,
5-27. The first number (5) is the number of fiberglass
plies in the spring. The following number (27) indicates
the relative stiffness of the spring. The higher this
number the stiffer the spring.
The total stiffness of the tuning spring stack is the sum of
the relative stiffness numbers. By various combinations
of different ply springs having different relative
stiffnesses, practically any desired total stiffness can be
obtained.
Note: Use 13 ply and lower springs. Do not use higher
ply springs as they will fail!
TUNING FOR NON-STANDARD
TRAYS
(
Note : See “Special Trays and Attachments”)
If it is necessary to tune the unit for a non-standard tray,
follow this procedure:
1. Attach the tray, making sure that all lockwashers are
in place and the fasteners tight.
2. Energize the unit at the nameplate voltage and
frequency.
3. (a) During tuning if a hammering or striking noise
occurs when the unit is turned off and on quickly,
the displacement is well in excess of normal.
Whether striking or not, if the displacement exceeds
the normal range for that particular size of tray
(see Tuning Guide- General Information), it must
be reduced by substituting a tuning spring leaf or
leaves of less stiffness, or by subtracting one or
more leaves, until approximately normal full voltage
How to Measure Displacement
Position an Eriez displacement sticker on the outer side
of the tray, near the rear of the tray and at an angle of
25° from vertical (see Figure 3).
Deflection (Displacement)
HD units are normally set at approximately 9/64-11/64
inch (3.5-4.3 mm) tray deflection. This can be checked
with an Eriez deflection sticker.
The sticker is read while the equipment is operating, by
looking at the optical illusion in which the printed circles
appear as double. Read the deflection where a pair of
circles just touch together.
A sticker is shown actual size in Figure 3B.
TIE BAR
REAR TUNING
SPRING STACK
Figure 2
DISPLACEMENT STICKER
Figure 3
1/8
9/64
5/32
11/64
This is how the circles
would look if the tray
deflection were
5/32 [3.9 mm]
Figure 3B