When a process requires accuracies greater than 1 to 1 1/2%
or it is necessary to determine actual feed rates, feeding
by weight loss is the better 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 weighed 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 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 on the bulk density of the material, determines the
capacity of the load cell to be used.
Our "BETTER-WEIGH"® feeder, Model BWL, incorporates
a level 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.
 |
MODEL |
Feed
Rt.
(cu/ft/hr) |
"OD"
Dim |
"L"
Dim |
"A"
Dim |
BW(P
or L)-1 |
3 |
1
1/2 |
8 |
2
3/4 |
BW(P
or L)-1 1/2 |
8 |
2 |
8 |
2
3/4 |
BW(P
or L)-2 |
20 |
2
1/2 |
8 |
2
3/4 |
BW(P
or L)-3 |
60 |
3
1/2 |
12 |
3
1/4 |
Hopper
Size |
"E"
Dim |
"F"
Dim |
"H"
Dim |
2
CU FT |
22 |
20 |
30 |
3
CU FT |
26 |
22 |
34 |
5
CU FT |
28 |
26 |
38 |
|
| |
|
| CONTROL
FEATURES - BATCH LOSS-OF-WEIGHT FEEDER |
With
the "BETTER-WEIGH"® batch feeder model BWP,
accuracies of +/- 0.5% can be achieved with 2 lb. batches
and +/- 0.25% accuracy with 5 lb. or greater batches with
time spans of 30 to 90 seconds. The BWL model can easily
produce an accuracy of +/- 0.5% in 1 lb. batches.
The metalfab Batch Controller is used to control the fast
(bulk) and slow (dribble) speeds of our "BETTER-WEIGH"®
feeders.
1. The bulk dribble targets are entered through the front
panel or down loaded to the indicator using RS-232 or optional
RS-485 and Allen Bradley Blue Hose communications. The feeders
fast and slow speeds are set manually and re initiated by
the weigh indicator's twenty programmable steps.
2. In addition to the fast and slow speed outputs, the indicator
has two additional outputs that can be configured for a
refill, batch complete or general alarm conditions.
3. Formatting printing can be done and is activated by one
of the programmable steps or by pushing the print button
located on the front panel.
4. The indicator is also supplied with four accumulators
and their values printed through the print functions.
5. Vibration elimination is used to remove motor and machine
noise from the raw digital data used for weigh indication.
It is also an added benefit when using vibration to assist
with feeding.
6. Both the SCR DC drive and weigh indicator are mounted
in the same NEMA 4 enclosure having a power on/off switch
with light, Jog/Batch and Abort/Start selector switches.
7. Normally the control is supplied 230 VAC. As an option,
115 VAC can be supplied.
