| United States Patent | 5,370,322 |
| Gray , et al. | December 6, 1994 |
Filtering particulate cellulosic-based material
Abstract
A method is provided for filtering shredded cellulose-based material, for example to enable the formation of a mixture containing cellulose dispersed in a solvent for cellulose such as
amine oxide. The shredding operation creates both fine particles of cellulosic material ("pulp dust") and large particles of cellulosic material. The shredded cellulosic material is passed through a separator to separate the pulp dust from the large particles of cellulosic material and the pulp dust is subsequently recovered in a filtering process.
| Inventors: | Gray; Gary E. G. (Westwood Heath, GB), Pennicott; Philip (Poynton, GB) |
| Assignee: | Courtaulds Fibres (Holdings) Limited (London, GB2) |
| Appl. No.: | 08/067,427 |
| Filed: | May 24, 1993
An object of the present invention is to return or recycle pulp dust, created during shredding and comminuting of cellulosic material, to the larger comminuted particles or flakes of pulp of cellulosic material produced during shredding.
In practice we have found that in order to produce high quality cellulose mixtures having a relatively high solids contents, it is desirable for cellulosic material, e.g. from rolls or sheets of wood pulp or wood pulp flock, to be shredded into relatively large flakes or particles, e.g. from 1 to 20 cm.sup.2, with the cellulosic material being compressed as little as possible at its cut edges. However we have found that typically, in the process of shredding and comminuting the cellulosic sheet material, a significant amount, e.g. up to about 2% by weight, of the cellulosic sheet material is converted into pulp dust which is conventionally lost to the process.
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