Newsletter 2/2007
Dear customer,
We would like to take the liberty of presenting you with our second newsletter
of the year with which we want to inform you about new developments and products
from Lipp Mischtechnik.
New Intensive Mixer:
Drastic Increase in Mixing Action with the TRIQUENCE® - Mixing Mechanism
TRIQUENCE® is the designation for a novel mixing mechanism that can be used in horizontal intensive mixers. It significantly increases the mixing action of mixing mechanisms with plough share mixing elements. Compared to mixing mechanisms of conventional design mixing times are reduced by up to 50% (e.g. 1.5 minutes instead of 3 minutes). For many applications chopper heads can be dispensed with if TRIQUENCE® is being employed.
Design and mode of operation of horizontal intensive mixers
|
With difficult mixing tasks such as the wetting of powders with fluids or the addition of fibrous components into powders the introduction of shearing forces is of primary importance to dissolve emerging agglomerates and to achieve the required dispersive action respectively. The mixing elements wiping along the mixing drum wall form between its outermost edges and the drum wall a narrow gap, which shears the mixture. In the process, every mixing element covers a well-defined ring-shaped area of the drum. In conventional mixing systems this occurs once per rotation. |
 Illustration 1: TRIQUENCE® - mixing mechanism for mixers with 5000 l gross capacity |
Consequently, the following parameters fundamentally influence effective shear force mixing in horizontal intensive mixers:
- Narrow gap - referring to the distance between mixing elements and the mixer wall.
- The angle of mixing elements with respect to the mixer wall.
- Arrangement of the mixing elements on the mixing shaft.
- High rotational speed of the mixing mechanism commensurate with the mixing process.
- Numbers of passes of each drum area per revolution of the mixing shaft.
How does TRIQUENCE® work?
Wings/wipers are located at the tip and the end of the ploughshare-like mixing elements.
These respectively traverse the operating range of the neighboring blades. Thus every operating range is being passed 3 times per shaft revolution, instead of just once as is the case with a standard mixing mechanism.
What does this bring about?Because of the significantly higher rate of rearrangement of the mixture it is being sheared more particularly in the peripheral zones. The mixer thus acquires improved dispersing behavior. The effect is roughly as if the mixing mechanism was operating at at least twice the rotational speed without an accompanying raise in power requirements. The mixing action is so intensive that in many cases in which chopper heads are required in addition these can be dispensed with. With products which tend toward agglomeration during the mixing process the integration of chopper heads occasionally even leads to increased agglomeration. This is where the TRIQUENCE® - mixing system is particularly suitable. Fibrous products are rendered very well. TRIQUENCE® makes better results possible than mixers with built-in blade mills. Costs and Power ConsumptionMixers with TRIQUENCE® - mixing systems are only slightly more expensive than standard mixers. The additional charge ranges from 2 to 10 percent of the price of the mixer, depending on the size of the mixer. The bigger the mixer, the lower is the extra cost. The required power lies only about 10% above that of the standard mixing system. |
 Illustration 2: Active principle of the TRIQUENCE® - mixing system. Unrolling of the jacket with mixing elements speeding over it. |
Further advantages
TRIQUENCE® yields significantly higher heat transfer performance between the mixture and the heated or the cooled mixer wall respectively.
Correspondingly, heating and cooling processes, as well as drying and reaction processes are advantageously affected.
For vacuum driers heat transfer coefficients have been measured that were greater by a factor of 2.5 than those of driers with standard mixing systems.