USRE8198E - Improvement in wood-grinders for paper-pulp - Google Patents

Description

F. A.` CUSHMAN. Assignor to W. A. RUSSELL Wood-Grinders for Paper-Pulp. No. 8,198.

2 Sheath-Sheet;l 1.

Reivssued April 23, |878.

@NAM

FRANCIS A. UUSH MAN,

UNITED STATES PATnNTOFF-Icn.

or LEBANON, NEW HAMPSHIRE, AssIGNon To WILLIAM A. RUSSELL.

IMPROVEMENT WOOD-GRINDERS FOR PAPER-PULP.

` Specification forming part of Letters' Patent No. 153,190, dated July 21, 1874; Reissue No. 8,198, dated Y April 23, 1878; application filed March 29, 1878.

To all whom 'it may concern:

Be it known that I, FRANCIS A. CUSHMAN, of Lebanon, Grafton county, New Hampshire, have invented a new and useful Improvement in the Art of Reducing Wood to Pulp, and also certain new combinations of machinery, by means of which said improvement in the art may be worked out; and that` the following, taken in connection with the drawings, isa full, clear, and exact description thereof.

n In the drawings, Figure lis a vertical sectlon through certain apparatus by means of which my improvement in the art may be worked out. Fig. 2 is an elevation of the same, taken at right angles to that of Fig. 1. Fig. 3 is a plan of the same. Figs. 4 and 5` are perspective views of details, and Fig. 6 'is a ketch illustrating the improvement in the ar Y Prior to the date of my invention wood had been submitted to the action of grinding-surfaces, in order to reduce it to pulp, 'with the grain in various relations tothe surface and to the line of motion thereof. The best known ways of presenting thebcrs of the woodto the surface are those of Christian Voelter, who

` presented the ends of the bers to the grinding-surface so that the surface acted to cut or break the fibers in planes perpendicular to their length; of Brooman, who submitted blocks of wood to the action of a grindingsurface in lsuch manner that the grain or bers were not in the same plane or curve. as that of the` surface, but inclined thereto at various angles, depending upon the size of the grindstone and the length of the block; and of Henry Voelter, who so presented the blocks to the grinding-surfacethat the bers lay substantially in the plane or curve ofthe grindlng-surface, and were acted upon by the asperities of the grinding-surface in lines substantially perpendicular to the length of the bers, so that the bers were,as, it were, rolled out of the block.

This latter was, .so-fai' asI know, the preferred way of de'bering wood prior to myinvention, as it produces long bers and a givenquantity of ber with a .comparatively small expenditure of power. The diculty with this plan is that the bers are rolled out too easily, and consequently are, when rolled out, too far removed from 'ultimate berin fact, often composed of bundles of bers, and are also too little broomed up or bruised to felt to the best advantage.

'Henry Voelters feed-boxes were arranged, with reference to the grindin g-surface, with the intention of so holding the blocks of wood'that the asperities of the surface would, as before stated, act upon the bers in lines perpendicular to the length thereof, and it was his intention that the asperities should act substantially in such lines.

Now I have discovered that ner bers, bers more regular in length and thickness, and bers more near to ultimateber, and more broomed up, can be produced by submit- `ting the wood 'to the grinding-surface with its bers substantially in the curve or plane of the grinding-surface; or, in other words, with the whole ber resting on the grinding-surface, so that the whole of each ber is substantially exposed to the action of the grindingsurface, and at the same time in such manner that .the asperities of the grinding surface move diagonally across the bers, thereby partly rolling and partly pullingthe bers out of the block of wood.

I have devised machineryby means of Which this improvement in the art may be carried out, but desire it to be understood that this improvement may be worked out by other forms of grinding-surface than that represented in the drawings.

The machine represented in the drawings is of the class that employs a revolving stone or rasping-cylinder, which, when revolved like a grindstone, debers the wood in the manner before described.

In the drawings, sented at A, supporting the shaft on which the stone or grinding-wheel Bis secured. C is a hood or cover partially iuclosingthe wheel and supporting, thehoppers or feedboxes.` 'D Dhare hoppers or feed-boxes supported by the hood,iu which the blocks of wood to be ground are placed.

Plungers or followers for forcing the blocks of wood upon the grinding-surface'are represented at E J the latter actuated, as feedplungersv sometimes are, by weights, and the former, E, by a piston-rod, I moved b y a piston, H, lying within a cylin er, F, which pisa strong frame is repre- 2 alos ton is to be forced downv'by pressure eilerted by a column of water in a pipe, or `by'water forced into the cylinder by a pump; and this pressure may be regulated by suitable appliances. The hydraulic by the uprights G G.

In the Henry Voelter machine, before referred4 to, the feed-boxes were arranged in piston is supported such wise that their sides were parallel with.

the axis of the grindstone, and, as the grain of the wood lay parallel with these sides, the` ,per-

' to planes which bound the sides' of the stone,

instead of perpendicular to the line of motion of the asperities of the grinding-surface, and to planes bounding the sides of the stone, as in Henry Voelters machine. When blocks split and sawed from a tree-trunk or sawed from a beam are placed in these boxes, they are to be so placed that the fibers to be acted upon lie substantially inthe surface of the stone, or in curves parallel with that surface, but are inclined in their length to the directioir or line of motion of the asperities of the stone, (see Fig. 6,) so that these asperities attack the sides of the fibers not in' lines perpendicular to their length, but in lines which are diagonal to the length of the fiber, thereby rtly rolling out and partly pulling out the ers. i' In order that the wood may be'reduced to pulp, water is supplied in any usual way. The grinding-wheel represented in the drawings is constructed as follows: First, a strong pulley or cylinder, B, is keyed upon a shaft,v

and upon the periphery of this pulley are lscrewed segmental plates of metal, b, provided with inclined flanges c c on their peripheries,

near the edges thereof, and with a dovetailed4 rib, d, between 'the iianges. Outside of the flanges are bolt-holes, through which screws may pass to attach the segments to the pulley. This construction is represented at Fig. 4, and an alternative construction is so clearly represented in Fig. 5 that it needs no further description. l

Before or after these segments are bolted to the pulley they are coveredfwith a layer `of grinding material, a, in a plastic state, said material being well known, and consisting chiefly of emery, corundum, quartz, or'other suitable substance. This material is held in place by the inclination of the lianges and the dovetailed rib d, and may be applied by means of a proper mold, and when applied constitutes a proper cylindrical grinding-surface.

In the operation of this machine the wood.

is placed in the hoppers the stone or grinding-wheel vis put in revo ution, and the wood 1s pressed upon the grinding-surface either by weight or by the hydraulic cylinder, its piston,

water-wheels.

and piston-rod; and when the blocks of wood are placed in the hoppers or feed-boxes in such manner that the bers thereof are supported inthe boxes with their lengths in lines diagonal to the line of motion of the asperities of the grinding-surface, then the wood is delibered or reduced to pulp in the improved manner hereinbefore set forth.

When wood lis, reducedto pulp by asperities of a grinding-surface acting upon fibers thereofl in the manner described, more power is required, so far as I can ascertain, to reduce a given quantity of wood to pulp than is required by proceeding according to Henry Voelters method; but thisincreased Iexpenditure of power is more than compensated by the superior quality of the pulp.

I do not claim an apparatus for feeding blocks of wood to be'ground which is actuated by compressed air or gas, as such apparatus differs radically in its mode of operation from my own, as' th`e elasticity of the air or gas would tend to cause a spring or jumping action in feeding, and it would be very dicult, practically, to prevent the escape o f the air or gas from the cylinder under the pressure to which it is necessarily subjected, whereas, by the use of water, I obtain a pressure as solid as -if the water were a stick or rod of iron; and, with a pump or a. water-column, the pressure is easily applied and maintained, as slight leaks .would do no special harm, especially if the hydraulic cylinder were supplied by a column of water from the reservoir which drives the I claim as of my own invention- '1. The herein-described improvement in the art of reducing wood to pulp, said improvement consisting in defibering a block ,by a grinding-surface the asperities of which act upon the'fibers in lines diagonal to their length, when said fibers are held, substantially as described, with reference to the grinding-surface.

2. In combination with a stoneorgrindingwheel, andl with a plunger or follower to force the wood in contact with the wheel, a hopper or feed-box arranged with its sides diagonal to the line of motion of the asperities of the grinding-surface, the combination being and acting substantially as described.

3. A grinding-wheel composed of -a central pulley of metallic segments, provided'with inclined flanges and dovetails, and of a compositiou applied to the segments, the whole being substantially such asset forth. y

4. In combination with a feed-box and plunger, a hydraulic cylinder and piston apparatus, substantially such asdescribed, for lilling said cylinderH with water under pressure, whereby Wood supported in 'the feed-boxes is forced against a grinding-surface by the action of the water, substantiall as described.

' FRAN OI v A. CUSHMAN.

Y Vitnesses: l

.Luanz hHomms, J. HENRY TAYLOR.

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