| Titre : |
A better mix : Dual-axis centrifugal mixers can handle small batches of high-viscosity products quickly and efficiently |
| Type de document : |
texte imprimé |
| Auteurs : |
Stephen Schmidt, Auteur ; E. W. Kaufmann, Auteur |
| Année de publication : |
2010 |
| Article en page(s) : |
p. 33-35 |
| Langues : |
Américain (ame) |
| Catégories : |
Colles:Adhésifs
Malaxeurs et mélangeurs
Mastics
Mélanges (chimie)
|
| Index. décimale : |
668.3 Adhésifs et produits semblables |
| Résumé : |
The axial flow paradigm has long been one of the most predominant mechanisms of mixing. This flow pattern is generally produced by a single-shaft mixer with axial flow impellers. It is characterized by flow down the center of the batch to the bottom of the tank, which is then deflected outward toward the wall by the container bottom. It then travels up the vessel wall and back across the surface, as shown.
The single-shaft mixer has limited use in the preparation of adhesives and sealants, as the axial flow patterns are difficult to reproduce in the high viscosities these products typically exhibit. When viscosity rises, mixing efficiency drops as distance from the mixing blade increases. Increasing the blade speed does little to compensate for loss of flow at the outer reaches of the tank. In addition, vortexes become deeper as speed increases, resulting in air entrainment.
To overcome these limitations, multiple shafts were introduced to provide both the shear and flow necessary to produce a uniform product. Multiple-shaft mixers are common in the production of adhesives and sealants. However, these multi-shaft mixers do not produce the same flow patterns. They also require additional clean-up, limit the ability to produce small batches, and do not always mix as efficiently in small sizes as larger production machines. In many cases, the only option available has been to manually assist the mixer or manually mix altogether. |
| Note de contenu : |
- Dual-axis centrifugal mixers
- Surface flow
- Internal flow
- Real-world mixing
- FIGURES : 1. Axial flow in a single-shaft mixer - 2. Interior of a dual-axis centrifugal mixer - 3. Surface flow pattern - 4. Internal flow pattern - 5. Powder, paste and liquid mixing |
| En ligne : |
http://www.adhesivesmag.com/articles/89050-a-better-mix |
| Format de la ressource électronique : |
Web |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=25882 |
in ADHESIVES & SEALANTS INDUSTRY (ASI) > Vol. 17, N° 7 (07/2010) . - p. 33-35
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