WO1982001326A1

WO1982001326A1 - Wood pulping apparatus

Info

Publication number: WO1982001326A1
Application number: PCT/US1981/001350
Authority: WO
Inventors: Preheater Co Inc Air; Robin B Rhodes
Original assignee: Air Preheater
Priority date: 1980-10-15
Filing date: 1981-10-07
Publication date: 1982-04-29
Also published as: IT1139535B; IT8124479A0

Abstract

Apparatus for reducing a bulky product to one of finely divided consistency. The invention utilizes two counter-rotating cylinders (10 and 32) of one within the other. The axes of rotation of the cylinders are substantially parallel but not co-linear such that the outside surface of the inner cylinder lies adjacent to but not in contact with the inner surface of the outer cylinder, thus forming a crescent shaped annular void (56) between the two cylinders. A product to be refined is introduced into the crescent shaped annular void between the rotating cylinders. Frictional forces effected by the counter-rotating cylinders cause the product to roll upon itself and be progressively refined to a finely divided form that is continuously expelled through opening (58) to an exhaust manifold (62). Steam produced in the frictional refinement of the product is directed through openings (64) into the interior of the inner drum (32), and thence through hollow trunnion (36) to an outside place of use.

Description

WOOD PULPING APPARATUS

Background of the Invention

The present invention is directed to a refining apparatus that is used to reduce a bulky particulate product to one of finely divided form, while simultaneously utilizing the heat developed in the refining operation in the useful production of steam.

Various arrangements exemplified by U.S. #4,205,798 and U.S. #4,162,769 have been developed to best utilize the force of a rotating body within a cylindrical drum to frictionally reduce particulate matter to a finely divided form. Other patents represented by U.S. #4,185,784 and U.S. #4,199,114 recognize the value of heat generated in the course of frictional abrasion of a product, and subsequently utilize the heat so produced as a method of improving the operating efficiency of the device. It is an object of the present invention to simplify the action of a refining device, reduce the maintenance required to keep it operable, and improve its operating effectiveness. Moreover, it is an object of the present invention to effectively duct the steam away from the space in which it is produced in a rotary refining apparatus so that it may be utilized in other than the refining operation.

Summary of the Invention

The above objects are attained chiefly by providing two counter-rotating cylinders, one within the other, with their axes of rotation substantially parallel to one another but not co-linear. The cylinders are rotated rapidly and positioned so that the outside surface of the inner cylinder is in proximity with the inside surface of the outer cylinder whereby there is formed a substantially crescent shaped annular void therebetween. A product to be refined is continuously introduced into the crescent shaped void between cylinders whereby frictional force produced by the counter-rotating cylinders causes the product to roll upon itself, thereby effecting refinement. As refinement progresses, the influx of new product moves the refined material axially until it is discharged from the apparatus. Heat, in the form of steam produced in the refining process, is allowed to escape through a separate passage means whereby it may be independently utilized outside the apparatus.

Brief Description of the Drawing

Figure 1 is a schematic cross-section of the invention, and Figure 2 is a view of the device as seen from line 2-2 of Figure 1.

Description of the Preferred Embodiment The apparatus consists essentially of an outer cylindrical drum 10 having tubular trunnions 12 projecting axially from end plates 14 at opposite ends of said drum. The trunnions are mounted in bearings 16 which in turn are supported by bearing support structure 18. The cylindrical drum 10 is provided with drive means such as that shown symbolically at 22 whereby it may be rotated about its axis by a conventional prime mover, not here illustrated.

An end plate 14 of the outer drum 10 is made reirovable by bolt fasteners 24 whereby said plate may be removed to install an inner cylindrical drum 32 enclosed by end plates welded integrally thereto and axially aligned with tubular trunnions 36 extending outward through the outer trunnions 12. The trunnions 36 are supported by bearings 38 which are held up by the same bearing suppcrt structure 18 that supports bearings 16. An adjustment means shown schematically at 42 installed at one or both ends of the apparatus is provided to move the inner drum relative to the outer drum whereby the distance between their parallel axes may be varied slightly to similarly vary the distance between the inner surface of the outer drum and the outer surface of the inner drum.

Conventional sealing means schematically disclosed at 44 and 46 preclude the leakage of fluid from the space 56 between the rotating drums and thereby enable one of trunnions 36 to extend laterally to a driving means shown at 52, thereby permitting the inner and outer drums to be freely rotated about their respective axes without permitting leakage from the space therebetween. A product inlet passageway 54 through bearing support 18 permits the supply of a particulate product to be refined into the crescent shaped annular void 56, while a discharge opening 58 in end plate 14 at an axially remote part of the outer drum receives a refined product that has been subjected to the relatively moving surfaces of the outer and inner drums, and discharges it to a manifold 62 that is connected to a suitable receiver for the refined product.

The outer surface of the inner drum and the inner surface of the outer drum may be hardened and configured in such a manner that is most suitable for the refining of any product to any given consistency. Inherent in the process of refining a particulate product is the production of heat, commonly dissipated as steam generated by heating the water content of the particulate product. Depending upon the moisture content of the particulate product, water may have to be added thereto to prevent a sub-normal moisture ratio.

Accordingly, one or more openings 64 in the end plate of the inner drum 32 permit steam from the void 56 to enter the inner drum 32 and be exhausted through hollow trunnion 36 to a location of suitable use. In operation a suitable product to be refined is fed into a feeder and product inlet passageway 54 where it enters the crescent shaped annular void 56 between the counter-rotating drums 10 and 32. Centrifugal force imparted to the product to be refined at first disposes the product in contact only with the inner surface of the outer drum. However, frictional force imparted by the counter-rotating drums then causes the product to roll upon itself and break down or be refined. As rotation of the drums continues, the product continues to break down into smaller and ever smaller particles by mcving into the space defined by the nearly adjacent drums. The refined product continues to move progressively axially until it reaches discharge opening 58 and manifold 62. Steam from heat produced by frictional forces generated by the refining process escapes from the crescent shaped void 56 through openings 64 in the inner drum 32 and is then directed by passageway 66 in the inner trunnion 36 to a location of suitable use outside the apparatus, while centrifugal force imparted to the material in the crescent shaped void moves the lighter particles outward to and through outlet 58 to manifold 62. During operation outlet 58 is substantially closed off with fine particles being thrown centrifugally outward, while openings 64 are maintained substantially clean and free from closure by centrifugal force of the rotating drum 32. Thus the continuous exhaust of steam into the inner drum and passageway 66 is assured, while some steam passing from void 56 through outlet 58 may assist in moving finely abraded particulate matter into the manifold 62 for exhaust to the outside.

Claims

1. Apparatus for processing a product comprising an outer cylindrical drum supported for rotation about an essentially horizontal axis, a rotatable cylindrical drum within the outer drum having a tubular trunnion at the axis of rotation lying substantially parallel to the axis of said outer drum and spaced therefrom to define an essentially crescent shaped annular void therebetween, means providing relative rotation between the inner drum and the outer drum, means for admitting a product to be refined to the crescent shaped annular void, means for withdrawing a refined product from the crescent shaped annular void, and means for the passage of steam generated by the processing of the product in the annular void into the inner drum and out the hollow trunnion.

2. Apparatus for processing a product as defined in claim 1 wherein the means for admitting the product to be refined and the means for exhausting the refined product from the crescent shaped annular void are positioned at axially spaced ends of the outer drum.

3. Apparatus for processing a product as defined in claim

2 including means for rotating the outer drum in one direction, and means for rotating the inner drum in the opposite direction.

4. Apparatus for processing a product as defined in claim

3 including cylindrical trunnions adapted to support axially opposite ends of the inner drum having an outlet passageway for the exhaust of steam, and an opening in the inner drum adapted to admit steam into the interior of said drum as generated by the frictional processing of the particulate matter.

5. Apparatus for processing a product as defined in claim

4 wherein the inner cylindrical surface of the outer drum and the outer cylindrical surface of the inner drum are formed into embossed patterns that increase the refinery action on particulate material therebetween.

6. Apparatus for the refining of wood pulp that comprises an outer cylindrical drum supported on tubular trunnions for rotation about a substantially horizontal axis, a rotatable cylindrical drum lying within the outer drum having a tubular trunnion means extending axially outward therefrom and having an axis of rotation parallel to and spaced therefrom to define an essentially crescent shaped annular void therebetween, means rotating the inner drum in one direction, means rotating the outer drum in the opposite direction, a feeder for admitting wood pulp to be refined to the crescent shaped annular void between rotating drums, an axially spaced opening in said outer drum for withdrawing refined wood pulp therefrom, and means in the inner drum for the passage of steam generated by the processing of wood pulp in the annular void whereby said steam may flow into the inner drum and out the tubular trunnion.

7. Apparatus for the refining of wood pulp as defined in claim 6 wherein the means for the passage of steam into the inner drum comprise openings therein that lie radially displaced from the opening in the outer drum for the withdrawal of refined wcod pulp therefrom.