Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – Waste paper or textile waste
Reexamination Certificate
2000-02-16
2001-10-09
Nguyen, Dean T. (Department: 1731)
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
Waste paper or textile waste
C264S914000, C264S918000, C241S027000, C241S024130, C241S024190, C241S022000, C425S222000
Reexamination Certificate
active
06299726
ABSTRACT:
FIELD OF THE INVENTION
This invention pertains to paper nuggets, and particularly to the manufacture of an aggregate stock of paper nuggets having mold-filling abilities and mutual interlacing properties.
BACKGROUND OF THE INVENTION
The enormous amount of waste paper disposed of in landfills has prompted many to explore other more ecological solutions to this reality. As may be appreciated, waste paper, even when made with a high percentage of post-consumer fibres, still contains whole-length wood fibres and can be re-used to manufacture a variety of products. In that regard, several methods and apparatus have been developed in the past for repulping waste paper and for manufacturing numerous useful paper-based products.
As examples of ecological products of the prior art, U.S. Pat. No. 5,230,943 issued on Jul. 27, 1993 to J. E. Pregont, discloses specific hollow flake-like shapes of free-flowing dunnage made from molded pulp and used as packaging material.
U.S. Pat. No. 4,123,489 issued on Oct. 31, 1978 to J. A. Kelly, discloses a method for converting paper materials into more useful forms for uses such as plant mulches, lightweight concrete aggregates, fertilizers, animal feeds and fuels.
PCT International Publication number WO 97/15184 published on May 1, 1997 discloses a method and apparatus for manufacturing paper pellets that are used as pet litter, insulating material and material for absorbing spillage of oil, chemicals and the like.
In another perspective, wood is a preferred building material in the residential and commercial construction industries. Wood is easily cut, chiselled, sanded, drilled and nailed to accommodate almost any shape and application. While wood is considered to be one of the most versatile building material available, concrete is also used in constructions requiring compressive strength, durability and resistance to the elements. In the past, extensive researches have been done, and a number of different composite materials have been developed in an attempt to obtain a single building material having the combined properties of wood and concrete.
In that respect and for ecological reasons as mentioned before, waste paper and other fibrous waste materials have been used and mixed with Portland cement, lime or other binders, to obtain construction blocks, panels and slabs that have good structural strength and heat-insulation properties. These building materials are lightweight, non-flammable and are easily worked with carbide tipped carpentry tools.
The manufacturing of these composite materials requires the mixing and impregnation of shredded paper or other waste fibrous materials with a cement slurry or other liquid binder. The binder-fibre slurry is dried and crumbled into aggregate material. These paper pellets are suitable for storage and for later use in the manufacturing of pre-cast objects such as building blocks, panels, slabs, beams, columns and cast-in-place structures. Such an aggregate stock of paper pellets for use in making building materials is the type of products which is of interest herein.
Examples of the prior art building materials manufactured with aggregate stocks of paper pellets can be found in the following documents:
U.S. Pat. No. 1,463,123, issued on Jul. 24, 1923 to F. J. McAllister;
U.S. Pat. No. 2,301,597 issued on Nov. 10, 1942 to B. E. Welty et al;
U.S. Pat. No. 3,705,837 issued on Dec. 12, 1972 to C. S. Breslauer;
U.S. Pat. No. 4,402,751 issued on Sep. 6, 1983 to B. B. Wilde;
U.S. Pat. No. 5,102,596 issued on Apr. 7, 1992 to K. Lempfer et al;
U.S. Pat. No. 5,134,023 issued on Jul. 28, 1992 to W -H E. Hsu;
U.S. Pat. No. 5,196,061 issued on Mar. 23, 1993 to R. C. Thomas et al;
U.S. Pat. No. 5,241,795 issued on Sep. 7, 1993 to F. A. Giroux et al;
U.S. Pat. No. 5,350,451 issued on Sep. 27, 1994 to E. W. Patterson;
U.S. Pat. No. 5,392,721 issued on Feb. 28, 1995 to W. Judd;
U.S. Pat. No. 5,643,359 issued on Jul. 1, 1997 to P. Soroushian et al;
U.S. Pat. No. 5,785,419 issued on Jul. 28, 1998 to P. A. McKelvey.
It will be appreciated that the strength of a building material made with paper pellets is directly related to the degree of interlacing of the pellets in the finished product. It is also believed that the insulating properties and the lightweight of the building material is directly related to the individual sizes of the pellets used in the manufacturing of this material. Paper pellets having a certain volume, as opposed to individual fibres, entrap air therein, which fact contributes to enhance the heat insulation properties and light weight of the building material made with the pellets.
Although various apparatus and methods were developed in the past to produce paper pellets of various types, it is believed that very little effort has been made to obtain paper pellets that have a substantial volume and a tailed configuration to promote interlacing. As such, it is believed that there continues to be a need in the industry for an aggregate stock of paper pellets or particles that is dust free, that can be stored in heaps, packaged in bags and that has good mold-filling abilities and in which the particles have interlacing properties. Furthermore, it is believed that there continues to be a need in the industry for equipment to manufacture such paper pellets without using excessive power.
SUMMARY OF THE INVENTION
In the present invention, there is provided a stock of waste paper nuggets of various shapes and sizes providing good mold-filling abilities. and in which a large percentage of the nuggets have tailed configurations for promoting an interlacing of the nuggets there-between and enhancing the mechanical strength of the products manufactured therewith. The stock of nuggets according to the present invention is manufacturable with simple equipment requiring less power than conventional shredders and blade-type comminuting devices.
Broadly, in one aspect of the present invention, there is provided a stock of paper nuggets for manufacturing composite building materials, wherein that stock of paper nuggets comprises a large portion of paper nuggets each having a twisted core, a broad end and a slender tail end. This stock of paper nuggets is advantageous for being composed of cohesive entities which can be manipulated on a construction site as conventional aggregate, or sold to the public in bags for use in backyard projects for examples. Because of the interlacing properties of the paper nuggets this stock can be mixed with a binding agent and set in a mold without specific attention, for nonetheless manufacturing building materials having relatively good mechanical properties.
In accordance with another feature of the present invention, there is provided a method and apparatus for manufacturing an aggregate stock of paper nuggets for use in the manufacturing of composite building materials. This method comprises the steps of:
a) repulping waste paper into a waste paper slurry;
b) dewatering that waste paper slurry for forming a wet mulch of waste paper in which a water content is substantially equivalent to a water absorption capacity of paper fibres in that wet mulch; and
c) simultaneously swirling the wet mulch, extracting fragments from the wet mulch and rolling these fragments against the wet mulch.
This method is known to produce an aggregate stock in which a substantial portion of the mentioned fragments, referred to herein as paper nuggets, have a twisted core and an oblong shape with a broad end and slender tail end.
This method is preferably carried out with one or more spherical rotors each having curved round bars for penetrating the wet mulch. The method can be carried out with a single hand-held rotor and a portable container, for small projects for example, or can be carried out with several rotors suspended in a large trough for commercial production of an aggregate stock.
Still other features of the aggregate stock according to the present invention are that a manufacture thereof reduces the amount of waste paper going to public dumps and landfill. The paper nuggets do not contain binding
Andersen Erling Jim
Andersen Erling Reidar
Nguyen Dean T.
Theriault Mario
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