Conair TrueBlend TB500-4, User Manual

Page: 41 / 150

TrueBlend ™ Structure and Function
Edition: February 2007 39
5.4.1 Gravimetric mode
The metering sequence is identical as outlined below with every metering cycle
unless Precision Additive™ (PREC) is selected:
1 The regrind is metered by the vertical cone valve as a percentage of the
whole batch and fed into the weigh bin.
2 The required quantity of natural material is calculated by the controller and
dispensed as the next component.
3 The additive natural (Add N) is metered as percentage of the natural mate-
rial(s).
4 The additive batch (Add B) is metered as a percentage of the total batch.
The remainder of the cycle is the same with all operating modes and is described
in 5.2 Brief description of the functional units.
5 Precision Additive™ applies to a low percentage (<2%) color or additive
natural material which is a critical component of the process. The Preci-
sion Additive can only be applied to one additive natural position. When
selected that material is dispensed before the natural material, but after
regrind if being used. The Precision Additive™ is dispensed and weighed.
Then the natural material is dispensed and adjusted for any minor varia-
tion with the Precision Additive™ to assure the proper ratio; thereby, as-
suring this critical component is held to the actual target setting. Then the
balance (if selected) of additive naturals are dispensed to their setpoint
percentages of the weighted naturals, followed by any additive batch com-
ponents.
5.4.2 Volumetric mode
Volumetric mode is an emergency mode and must only be used if the weighing
system fails or in special circumstances.
The metering sequence is identical with every metering cycle.
1 First the regrind, then the virgin material is metered through the respective
vertical valves by time control and filled into the weigh bin. The load cell
does not operate in volumetric mode.
2 The additives/batch and additive color are added last through the smaller
vertical valves by time control.
The remainder of the cycle is the same with all operating modes and is described
in 5.2 Brief description of the functional units.
5.4.3 Combined mode
In combined mode one gravimetric cycle is followed by up to eight volumetric
cycles (number is adjustable). The total material throughput can be increased by
eliminating the weighing times. The metering cycle is described in
5.4.1 Gravimetric mode.