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Operating principles of Loedige
Equipment |
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Loedige equipment can be
categorized into 5 major classes: |
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Ploughshare®
mixers |
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Friction mixers |
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Ring layer mixers |
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Coaters |
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Vertical mixers |
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Modes
of Operation
Mixing and Processing in a Horizontal System -
PLOUGHSHARE® mixers
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Ploughshare® shovels rotate in special
arrangement along the horizontal shaft inside a horizontal,
cylindrical mixing drum. The size, number, positioning, geometric
shape and peripheral speed of the mixing elements are coordinated
for three-dimensional movement of the components inside the mixing
drum. The resultant turbulence, with constant, total product
mobility caused by the mixing elements, prevents the formation of
dead or static zones and results in gentle, precision mixing within
the shortest possible time.
Mixing elements lift product during radial
movement from the wall of the drum thereby preventing particles from
becoming squashed between the wall and the shovel. The hurling and
whirling process is, therefore, highly suitable for mixing processes
in which the components have widely differing bulk densities,
particle sizes, rheological features and – relevant to
pharmaceutical production – highly different mass fractions.
In KM-Series continuous mixers retention time is
controlled by means of a weir, which can either be fixed or
adjustable (KM-DW version)
Modified Ploughshare® shovels, ie
Becker shovels, can obtain this effect even more specifically for
certain cases. New applications can be developed with the
innovative, recently patented Isomix® elements in
compliance with specified operational parameters.
In the case of special applications and
particularly when liquid is added or during granulation processes,
it is sometimes necessary to back up the mixing effect by using
separately driven, high-speed choppers.
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Internal layout
FKM-series batch mixer |
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Weir in a
KM-Series continuous mixer
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Mixing and Processing in a Horizontal System -
RING LAYER mixers
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The product to be mixed flows through the various mixing zones
in a horizontal, cylindrical mixing drum. Mixing elements,
designed in each case for transporting, dispersing and mixing
the product, guarantee optimal granulating, mixing and – if
necessary – compacting. The transport elements near the inlet
produce a ring of mixing material which is conveyed axially
through the mixing drum. The mixing and dispersion elements
cause friction of the solid particles in this compact product
ring between the individual particles and against the wall and,
even when liquid is only added in small quantities, a uniformly
structured granulate material is obtained. |
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CB-Series
continuous mixer |
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Mixing and Processing in a VERTICAL mixer
A three-arm mixing element rotates close to the wall and with
minimum clearance from the bottom of a vertical mixing
container. The special shape of this element and its peripheral
speed are coordinated in such a way that the mixing product is
circulated as a vortex and thereby accelerated horizontally and
vertically. This mode of product movement assures rapid,
intensive mixing, even in the case of components with widely
varied particle shapes and sizes, bulk densities and surface
condition. High mixing precision is obtained within minimum
time. If necessary, a separately driven chopper disperses lumps,
distributes liquid uniformly and promotes wet granulation. The
point of granulation can be controlled as required. |
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KUM-Series
vertical mixer |
Mixing and Processing in a vertical FRICTION
mixer
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A special combination of mixing impellers rotate in a vertical,
high-cone mixing container. Considerable energy is introduced
into the mixing product due to friction caused by the
coordination of the shape and peripheral speed of the mixing
elements. The lower impeller, rotating close to the bottom of
the container coverts the mixing product into a circulating
vortex and accelerates it into horizontal and vertical plains.
The upper circular impeller located above the lower impeller
backs up this effect by counteraction to such an extent that the
vortex is accelerated and a second, inner vortex movement is
created which superimposes the first vortex. The result is high
speed, gentle mixing and heating of the product at precisely the
specified heating temperature. Undesirable temperature peaks or
local overheating is avoided.
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Impeller
arrangement in a PAPENMEIER®
TSHK-Series friction mixer |
Coating in Lödige LHC Coaters
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Lödige LHC Coaters are used for different shapes
of tablets, capsules and pellets and operate on the co- urrent,
underpressure principle. Dry air flows through an air inlet inserted
through the front of the machine into the centre of the drum and
flows in the same direction as the spray mist of coating solution
onto the material bed. Dry air flowing through the material bed is
extracted by an exhaust fan through the perforations running beneath
the bed and adapted exhaust channels. A wearproof, rotary disc valve
controls channelling of exhaust air guaranteeing forced circulation
of drying air through only the material bed inside the closed
coating drum. The co-current, underpressure principle in Lödige
Coaters ensures minimum waste of coating solution and optimum use of
drying air energy. With appropriately designed liquid dosing
systems, LHC units can be used for both film and sugar coating
processes. |
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LHC-Series
coater - retracted spray heads |
Additional Equipment Types available from
Loedige
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Continuous scraped
surface heat exchanger |
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Batch fluidized
bed dryer |
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Continuous
convection dryer |
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Vibratory dryer |
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Laboratory mixers
and reactors |
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Pin mixers |
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Vertical wet mixer |
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