Metalfab DBIC User Manual

INSTRUCTIONS FOR OPERATION & MAINTENANCE

MODEL DB1C (COMPACT)

VOLUMETRIC SCREW FEEDER

General Description

The DB1C Feeder is a simple, rugged and accurate Volumetric Feeder used for
the dependable metering of dry solids into process. It consists of a 5 ft._ hopper
as standard, a trough with an agitator/conditioner screw (except Model DB1C-6),
a metering screw and a variable speed drive, all mounted on a common base
plate.

The steep, sloped hopper, with it's large rectangular outlet, allows for material
flow to the agitator/conditioner screw. The function of this screw is to keep the
material in motion and also "condition" the material to a constant density while
insuring complete filling of the metering screw flights. Hence, accuracy is
maintained while rates are varied by screw speed changes.

Installation

The DB1C Feeder is shipped complete and ready for operation. There is no need
for bolting the unit into place, therefore, the four (4) levelers positioned under
the base plate are equipped with rubber pads. Room should be provided at the
discharge end to allow for screw removal. Normally, 20" clearance is sufficient.

Electrical Requirements

Standard units are provided with DC drives which have their own SCR controllers
capable of converting alternating current to direct current. They are single
phase units, 115 volt up to 3/4 HP and 230 volt for 1 HP or greater. The
controller may be mounted at the Feeder location or remotely. See separate
manual for controller instructions.

Note: Units with shunt wound motors have the field energized at all times with
the switch in the off position. If feeder is not to be used for an extended period
of time, it is recommended that an AC line switch be installed prior to the control
to power down the control.

Operation

After the Feeder is in place and wired, it is ready for operation. Units equipped
with DC drives can have their speed adjusted at anytime, i.e., with the unit
stopped or in motion. The dial provides for setting screw speeds to 1 part in

1000. Speed is increased by turning the potentiometer in clockwise rotation. As
noted above, AC drives must be in motion to change speed.

The hopper should be filled with the feed material and the potentiometer should
be set to #500 (#5 for AC drives). The unit should be allowed to run for 5
minutes before a 1 minute sample is collected and weighed. It is suggested that
5 or more samples be taken to assure the Feeder is operating properly. Once
the feed rate is known at setting #500, the required rate may then be obtained
by proper speed change. The drive and, therefore, the feed rates are linear,
hence, at setting #500 the Feeder will be operating at approximately half
capacity. As an example, if at a #500 setting a 20#/minute rate is achieved and
a 10#/minute rate is desired, change the setting to 250# and a 10#/minute rate
will be delivered. Take samples at 3 or 4 settings and plot a graph, setting
versus rate. From this graph, any feed rate may be selected.

Warning: Keep hands clear of all moving parts. Serious injury can occur.

Optional Hopper Vibrator

The hopper may be equipped with a pneumatically or electrically operated
vibrator if the feed product requires an assist to promote flow. The hopper is
also equipped with a baffle when a vibrator is used. The amount of vibration
should be minimal, just enough to promote flow. The vibrations of the
pneumatic vibrator may be adjusted by changing the P.S.I. setting (pressure
regulator, filter, gauge, etc., by customer), but should not exceed a maximum
pressure of 80 P.S.I. For electric vibrators, the vibrations may be adjusted by
changing the alignment of the centerlines of the eccentric weights.

The closer you align the centerlines of the two (2) OUTER weights with the
centerlines of the two (2) INNER weights, you are INCREASING the force. The
further you misalign the referenced centerlines, the more your DECREASE the
force. If the centerlines of all four (4) weights are completely aligned, you will
develop the maximum force available. Under all conditions, the OUTER weights
should be a mirror image of each other and the INNER weights should be a
mirror image of each other.

Any other arrangement could cause damage to the hopper, welds and
the feeder in general.