Metalfab Better-Weigh Feeders User Manual

Better-Weigh_ Feeders
Installation and Operating Instructions

Metalfab, Inc. Vernon, NJ 07462 Phone [phone] Fax [phone] [e-mail]

Contents:

• GENERAL DESCRIPTION

• INSTALLATION

• MAINTENANCE

• DISASSEMBLY

• ASSEMBLY

• PART LIST

• ENGINEERING DATA

• Load Cells

• Weigh Instruments

• Measuring Accuracy

• BATCH CONTROL

• CONTINUOUS CONTROL

GENERAL DESCRIPTION

When a process requires accuracies greater than 1 to 1 1/2% or it is necessary to record actual feed rates, feeding by

weight loss is the only method. Although material is fed in the same volumetric manner .... the screw flights are filled to

their maximum capacity with uniformly dense material .... required rates are actually monitored by a scaling system in

conjunction with either a batch or continuous controller. Weight of product being delivered is continuously monitored
against weight required.

The "BETTER-WEIGH" feeders are available in a variety of screw sizes and two (2) types of scaling systems. Model BWP
incorporates a platform scale, which consists of our unique screw feeder design with agitator/ conditioner screws, a
platform weigh scale and a controller. With the BWP, the total weight of the feeder and the weight of the product in the
hopper are sensed by the load cell in the platform scale and the combined weight, which will vary based upon the bulk
density of the material, determines the capacity of the load cell to be used.

Our "BETTER-WEIGH" feeder, model BWL, incorporates a lever balance scale system. With this method, the entire
weight of the feeder is counter balanced so that only the contents of the hopper are weighed. This system allows for the
minimal weighment of any product. open top hopper capacities of 2 to 5 cubic feet can be supplied with either model.

INSTALLATION

Even though we have designed our Better-Weigh

®

weigh assemble with stops, you can permanently
damage the load cell if you drop, overload or allow
anything to impact the scale. Care should be taken
to eliminate these occurances.

The gearbox has been filled with oil and shipped with the
vent plug installed. To prevent spills, Keep the feeder
Upright.

The feeder should be located in an area with minimal
traffic or disturbances and mounted on a stable and level
support. After placing the feeder into position, remove
the shipping clips from the upper and lower weighing

deck. The weigh deck’s corner and load cell stops were
adjusted during assembly and should not field adjusted.
Use the wiring schematic supplied with the Better­Weigh® feeder’s NEMA 4 enclosure and make your
connections to the motor and load cell terminals.

If you did not purchase our optional inlet and outlet
sleeves, connect the upstream and downstream
equipment with flexible connections. We recommend a
thin natural rubber or similar type material be used with
enough slack to prevent mechanical sticktion. The more
flexible the connections are, the better the accuracy you
can achieve.

Better-Weigh_ Feeders
Installation and Operating Instructions

Metalfab, Inc. Vernon, NJ 07462 Phone [phone] Fax [phone] [e-mail]

2

Note: There should be no rigid connections between earth and the Better-Weigh® feeder scale platform.

MAINTENANCE

Our standard Better-Weigh® Feeders are supplied with
metering screws having a standard agitator/conditioner.
Their purpose is to provide a constant supply of

densified product to the metering screw.

Standard machines use a "CinchSeal" rear seal. This is
a Mechanical Seal.

It is made up of an elastomer insert, which is held on the
drive shaft by a spring steel compression ring and
rotates with the shaft while pressing the two rotors
against both end plates.

There should be no product leakage. If there is, remove
the threaded plug on the side of spacer blocks and using
a screwdriver, tighten the compression ring in _ turn
increments.

If the seal is hot to the touch, loosen the compression
ring.

As a rule of thumb, the compression ring should
only be "three fingers tight".

All of the gearboxes are shipped with oil unless
otherwise specified. It's recommend that after the first
500 hours or 4 weeks of operation, and after each
succeeding 2500 hours of operation or every 6 months
thereafter (which ever occurs first) drain the oil, flush out
the case and refill to proper level using the
recommended oil or equivalent.

For normal operating conditions where the surrounding
temperatures are within the limits of 50° F to 120° F, use
AGMA Lubricant #8 COMP, 8EP or similar oil of equal
viscosity and composition. Below 50° F, use an AGMA
Lubricant #7 COMP, 7EP or equal.

The approximate oil capacities of the 2100 gearbox is 18
and the 2400 gearbox is 21 ounces.

As with our other DB1 volumetric feeder models, the
Better-Weigh® feeder is normally supplied with a 1 HP

DC shunt wound (having two fields in series) DC TEFC
motor. When using a SCR DC control having a
230/1/60 VAC input, the motor must be configured for
180 VDC Armature and 200 VDC connections. When
using a SCR DC control having 115 VAC input, the
motor must be configured for 90 VDC Armature and 100
VDC connections.

The motor’s wiring is terminated in a separate NEMA 4
enclosure mounted on the feeder base. When
connecting the motor, follow the schematic supplied in
the enclosure.

The Better-Weigh® feeder’s load cell is sized for each
application. As with the drive, the load cell connections
are terminated in the same NEMA 4 enclosure. Follow

the load cell instructions on the schematic supplied in
the enclosure.

. FEEDER DISASSEMBLY

To remove the screw; first remove the guard, loosen the
packing box’s compression ring and hollow shaft
gearbox’s setscrews. Unbolt the tube from the feeder’s
trough and remove the tube followed by the screw.

The gearbox, packing box, trough, hopper and cover can
be removed by unbolting the individual items.

FEEDER ASSEMBLY

The original packing box and tube gaskets can be
reused. We recommend that the trough and hopper
gaskets be inspected and replaced if required. If the
screw and tube were the only items removed, simply
reverse the disassembly instructions listed above.

If the Better-Weigh Feeder is completely disassembled,
the following applies. The trough, packing box and
gearbox should be loosely bolted in place. Insert the
screw through the trough,

packing box and gearbox. Bolt the tube into place and
tighten the hollow shaft gearbox setscrews.

Line up the gearbox, screw and trough and tighten the
bolts holding the trough to the weigh deck. Turn the
screw by hand and check for interference and alignment.
The gearbox and packing box can be tightened at this
time.