Plastic and nonmetallic article shaping or treating: processes – Forming articles by uniting randomly associated particles – With liberating or forming of particles
Patent
1989-10-31
1992-02-11
Theisen, Mary Lynn
Plastic and nonmetallic article shaping or treating: processes
Forming articles by uniting randomly associated particles
With liberating or forming of particles
47 64, 241 28, 264 401, 264 406, 264109, 264118, A01G 910, D04H 158
Patent
active
050874004
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process and a plant for making a product consisting of a mixture of entangled fibers and capable of constituting, in particular, a support which can be employed for cultivation out of soil.
The invention also covers the cultivation support produced according to the process.
It has now become quite common to practice, in some conditions, "out-of-soil" cultivation, that is to say on a support produced for this purpose and not on a natural terrain. Such supports can be made of various substances, organic or otherwise, such as plastics, sand, expanded clay, compost, sawdust, chips and the like.
In general, an out-of-soil cultivation support must exhibit a certain number of physical, chemical and biological properties. In fact, the support must, on the one hand, support the roots and, on the other hand, permit the circulation of air, water and fertilizer. In addition, it must preferably be nonputrescible, at least for a certain time, and made up of organic or other products, it must not exhibit phytotoxicity and must not promote the development of microorganisms which are harmful to plants. For various reasons, especially a relatively low cost, it is advantageous to make such a product from wood scraps or other lignocellulosic raw material.
In particular, it has already been proposed to employ as a support for out-of-soil cultivation a product consisting of wood fibers obtained by grinding wood. This operation is performed by the so-called "thermomechanical" method, commonly employed for the manufacture of papermaking pulp, and in which the shavings are subjected to a cooking process with steam and then pass into a disc grinder in the presence of steam under pressure.
A mixture is thus obtained, in which the proportion of water is very high and which must be pressed and dried when the site of use is far from the production site, to avoid the transport being too costly.
The use of machines which are already known for the manufacture of papermaking pulp is advantageous because such machines exist in the trade and their operation and control are well known. However, the properties required in a cellulose fiber pulp for the manufacture of papermaking pulp are not necessarily those expected from a product intended for the manufacture of a cultivation support.
The subject of the invention is, in contradistinction, a new process and a plant making it possible to perform the grinding of wood chips in conditions which are specially adapted to obtaining a product exhibiting a set of qualities which are particularly advantageous for the production of an out-of-soil cultivation support.
The invention also relates to the new product thus made.
In accordance with the invention, the grinding of the wood chips is carried out by passing them through a machine comprising at least two screws driven in rotation inside a barrel which encloses them and provided with flights of various pitches and in which all the characteristics are regulated so as to produce a controlled degree of grinding making it possible to obtain, at the outlet of the machine, a mixture based on isolated fibers and agglomerated bundles of fibers, of various lengths and particle sizes and, during the grinding, an adhesive binder is introduced into the barrel at a rate regulated as a function of the conveying conditions of the entrained material so that it may be distributed noncontinuously in the mixture of fibers, the temperature of the entrained material being controlled so as to delay the curing of the adhesive binder so that the latter does not take place within the barrel.
Advantageously, the grinding conditions are regulated so as to obtain a mixture of fibers whose lengths can range from a few microns to approximately one centimeter. In addition, the particle size distribution of the mixture is preferably such that at least sixty per cent (60%) of the mixture is retained on a 14 screen and that the proportion of fines passing through the 200 screen is less than ten per cent (10%).
The invention is based on the idea that instead
REFERENCES:
patent: 2757115 (1956-07-01), Heritage
patent: 3533563 (1970-10-01), Eriksson
patent: 3903229 (1975-09-01), Mark
patent: 4088528 (1978-05-01), Berger et al.
patent: 4218414 (1980-08-01), Hagg et al.
patent: 4402896 (1983-09-01), Betzner et al.
patent: 4605401 (1986-08-01), Chmelir et al.
patent: 4950444 (1990-08-01), Deboufie et al.
Theisen Mary Lynn
Wogegal S.A.
LandOfFree
Process for making a product serving as a cultivation support does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for making a product serving as a cultivation support, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for making a product serving as a cultivation support will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-780495