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Principle and Operation
The general principle of Rospen Industries
Loss in Weight feed system is to accurately weigh and
control the output of variable products either, continuously
or as a batch. As the name suggests, the Loss in Weight
concept is primarily based around the application of a
weigh system allied to PLC control, the outline specification
for the systems shown below. Whilst the weigh function
is at the heart of any Loss in Weight system it does not
directly impact on the material flow, therefore, the correct
design of the storage vessel and the choice of a suitable
material transfer is critical and is reflected in the
options available. With over 25 years experience, Rospen
continue to supply a range of Loss in Weight solutions
to key industries worldwide.
Screw Feeders
The loss-in-weight system is normally supplied
with a standard Rospen metering screw feeder either
single or twin screw from 12mm
to 250mm dia and output range from 1.0kg/hr to, in excess
of 100,000kg/hr. The selection of the correct
type of feeder from our extensive range is determined
primarily by the type and specification of the material
to be handled. Both single and twin, screw feeders are
equally as efficient, with the single screw mechanically
simpler and therefore, more economical. Both units share
the following features and benefits.
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Large inlet eliminates
material bridging.
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Tapered Conditioning Chamber de-aerates
fluidising powders or livens cohesive materials ensuring
screw runs completely and evenly filled.
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Suitable for use with very fine to
coarse, or fibrous, particulate products.
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Easily removable front cover provides
a safe and quick access for cleaning.
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Instant release of feed screw without
shaft seal disturbance.
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Ideally suited to industries that
require rapid clean down and product changes.
Rospen Standard Weigh
Platform
The standard Rospen weigh unit, manufactured
at the Stonehouse factory is of a robust design and
contains three, cantilever type load cells, which are
summated to automatically compensate for any off centre
loading that may occur during hopper filling and emptying.
Complete with transit locks, overload and side-impact
stops the units self-centralising mechanism also
eradicates inaccuracies due to temperature change.
The solid state design of the system provides for a
maintenance free operation and is enclosed in a stainless
steel dust cover with removable sides
On larger installations it is normal
to suspend the loss-in-weight hopper, complete with
the selected material transfer option, from 3 or 4
load cells to avoid large turning moments. The outputs
of the load cells are summated with a strain gauge
amplifier.
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