Continuous Mixing - Batch Mixing - Reactors - Dryers - Pharmaceutical - Polymer Processing - Dust Agglomeration - Operating Principles
Operating principles of Loedige Equipment
Loedige equipment can be categorized into 5 major classes:
• Ploughshare® mixers
• Ring layer mixers
• Vertical mixers
• Friction mixers
• Coaters
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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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CB-Series continuous mixer |
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KUM-Series vertical mixer |
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Impeller arrangement in a PAPENMEIER® |
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LHC-Series coater - retracted spray heads |
Modes of Operation
Mixing and Processing in a Horizontal System - PLOUGHSHARE® mixers
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.
Mixing and Processing in a Horizontal System - RING LAYER mixers
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.
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.
Mixing and Processing in a vertical FRICTION mixer
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.
Coating in Lödige LHC Coaters
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.
Additional Equipment Types available from Loedige
• Continuous scraped surface heat exchanger
• Batch fluidized bed dryer
• Continuous convection dryer
• Vibratory dryer
• Laboratory mixers and reactors
• Pin mixers
• Vertical wet mixer
