triple pass as well as single pass drums in our systems. Our triple
pass drums are really drums with seven drying zones which optimize
the drying of hygroscopic products, using well established principles
of heat transfer applying high air temperature with higher velocity
to the wet product (inlet of drum) and low temperature with low velocity
to dry product (outlet of drum).
drying zones and the high inlet air velocity result in relatively
low dryer outlet temperature required for good efficiency. The unique
exhaust gas recirculation system further increases efficiency and
it also reduces the exhaust volume to a scrubber system downstream.
The recirculation also raises the water vapor dew point and allows
heat recovery to make hot process water in tube and shell heat exchanger
by recovering the latent heat in the dryer exhaust. This condensing
process is also an effective particulate scrubber.
products and where space allows it, we offer our single pass drums
which are of course, of simpler construction than the triple pass.
To obtain the same inlet velocity as with the triple pass drum, we
use an inlet cone which expands to the drum diameter. In order to
increase contact between product and drying surface and also improve
dispersion of the product, some of our single pass drums have a central
displacement tube, our “bullet”.
have developed higher capacity drums which use the same tires, length,
and bases as the standard drums. This we do by an increased drum diameter
between the tires resulting in 15% to 20% more capacity.
the single pass drums usually require more force by the drum drive,
we have located the drive above the drum on a bridge structure. As
a result, the loading on the drum rollers and drum tires is reduced
increasing their useful life. Both types of drums have bolted-on tires
which can easily be replaced and squared, with all fasteners accessible
form outside the drum.
is a combination dust skimmer/air fan which can be used in the drying
system, this allows for a compact layout of the smaller system which
can be factory assembled on a steel frame for over the road shipment
and easy field installation requiring no or minimal foundations.
different types from inclined augers to vertical augers. The lastest
unit is vertical and is only 5 feet tall and is equipped with a ribbon
blender to break up lumps.
screening systems for separating dried bone chips from the meat and
sinew fraction. These systems are used after the dryer and consist
of a primary screen separator followed by vacuum gravity separator
tables made by Forsberg, Inc. with an air system. The bone can be
separated into large and small chips and are used for the extraction
of gelatine for film emulsions.
|There are certain applications
where a rotary dryer is not the best selection. Flash Tube Dryers
can be a more economical technology to use. The Flash Tube Dryer is
the same in many ways as the direct fired rotary dryer using a long
tube instead of a rotary drum. The flash tube is designed in such
a fashion that the product remains air born throughout the length
of the tube. The tube is sufficiently long enough to create a retention
time in the hot air stream to accomplish the required drying. The
tube can be designed as a serpentine shape to fit a limited space.
|Our smaller model dryers
can be assembled at the factory. The dryer is mounted on a steel frame
with all motors, piping and switches installed and wired. The control
panel can be mounted on the frame as well. If a remote location of
the control panel is selected, the wiring on the frame is connected
to a junction box. The dryer can be placed on a concrete floor and
no support piers are required.
All that is required
at the plant is wiring from the Motor Control Center to the junction
box on the frame, connection to the infeed/outfeed conveyors, and
connection of an exhaust duct to the scrubber if required.
a scrubbing system is required to remove particles from the dryer
exhaust gas. Duske Engineering designs particulate scrubbers which
incorporate a venturi scrubber and cyclone demister. The dirty gases
flow through the adjustable throat of the venturi where a series of
spray nozzles force water droplets onto the dust particles. Inside
the demister the swirling action forces particles to the outside of
the cyclone and ultimately out the bottom drain. The clean gas exits
from the exhaust stack.
The majority of the water is recirculated by a pump at the bottom
of the demister. A small portion of the water is bled off to the
drain. A set of level switches insures that the proper amount of
water remains in the sump of the scrubber.
Our scrubbers are of stainless steel construction and are custom
designed to accommodate the layout of the plant. An adjustable throat
is used in the venturi to optimize the pressure drop in the venturi
which is critical for the efficiency of the scrubber