US1465069A - Apparatus for grinding wood pulp - Google Patents

Description

Aug. 114, E923, 1,465.6)69

-J. J. WARREN APPARATUS FOR. GRINDING WOOD PULP Filed Aug. '7, 1920 3 Sheets-Sheet 1 Aug. M, 21923.

J. J. WARREN APPARATUS FOR GRINDING WOOD PULP 1920 3 Sheets-Sheet 2 Filed Aug '7 Aug. 1141 119233.

J J. WARREN APPARATUS FOR GRINDING WOOD PULP Filed Aug. '7, 1920 3 Sheets-Sheet 3 wvemcoz W M M w,

Patentwl Aug. M, 3923.

Ldtiddtid earner EDEN J. WARREN, OF BROWNVILLE, NEW YGRK.

APPARATUS FOR GRINDING WOOD P ULIP.

Application filed. August 7, 1920. Serial at. 4.0mm.

To all whom it may concern Be it known that I, Join: J. WARREN, a citizen of the United States, residing at Brownville, in the county of Jefi'erson, State of New York, have invented certain new and useful Improvements in Apparatus for Grinding Wood Pulp; and Ido hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the grinding of wood into the so-called mechanical pulp used in the manufacture of newsprint and other cheap papers. It is the object of the invention to make an improved grinder of the magazine type.

In order that the invention may be more clearly understood reference is had to the accompanying drawings disclosing certain specifiic embodiments thereof, and in which;

Figure 1 is'a transverse vertical section through the grinder, showing the relation of the magazine, the grindstone and the feeder chains;

Fig. 2 is a vertical section taken along the axis of the grindstone;

Fig. 3 is a sectional detail showing apparatus used to cool the shaft of the grindstone;

Fig. 4 is a detail of the same apparatus taken on line H of Fig. 3;

Fig. 5 is a horizontal section on an enlarged scale taken on line 5-5 of Fig. 1, and showing the chains and chain guides of the magazine;

Fig. 6 1s a detail on an enlarged scale taken on line 6-6 of Fig. 5, and showing the chain mechanism and apparatus used to bend the chain guides; and v Fig. 7 is a further detail of the feeder chain itself.

The magazine grinder shown in Figs. 1 and 2 comprises the ordinary cylindrical grindstone 1 ordinarily electrically driven mounted upon shaft 2 journaled within bearings 3, and enclosed within housing 1. Below this grindstone is an outlet channel 5. The-stone is securely fixed upon shaft 2 by means of bushings 6 and dished flanges 7 designed to hold the fiindstone in place even though cracked. l ounted upon the grindstone, and supported by housing 4, is a preferably vertical magazine 8 terminatin at its upper end in a. hopper 11, into whici i the wood to be ground is fed.

A positive and regulated feed of the w within the magazine 8 is secured by means or two pairs of oppositely positioned endless chains 9, the inner strands or runs of which move downwardly upon two opposite sides of the magazine. These sides are those which if extended would intersect the cylindrical face of the grindstone as clearly shown in Fig. 1. The specific manner in which these chains are mounted within the side walls of the magazine will now be described.

' The magazine itself comprises an outer metallic shell or casing 10 provided on its interior with a lining of wooden blocks 12, the cross section of the magazine at-its upper end being slightly greater than that at its lower end. Four vertical slots 13 are left in this wooden lining, in which are positioned flexible channel irons 14 which serve as guideways for the inner runs of the feeder chains 9. These channels 14 are fixed near the lower end of the magazine, but at their upper ends are held by bolts passing through slots within the channels, thus permitting free longitudinal movement the necessity for which willappear later. These channels 14 are tied together at suitable intervals by means of transverse tie plates 15 seated within horizontal slots 16 within the magazine lining, and normally bearing against the inner face of the metallic casing 10.

These channels 14 carrying the links of chains 9 are so designed that they may be bent inwardly and thus force the chains into closer contact with the wood within the magazine. This bending or flexing is accomplished by means of a series of hand wheels 17 situated at intervals aiong the outer sides of the magazine, and shown in detail in Figs. 5 and 6. A series of pairs of horizontal channel irons 18 are fixed upon the outer sides of the casing 10. Upon the outer a naeaoee flanges of these channel irons and in the planes of the chains are bolted plates 19 within which the hand wheels 17 are threadedly mounted. The inner ends of the threaded shafts 20 of hand wheels 17 are seated within bearing members 22, which in turn bear upon the outer ends of compression springs 23. The other ends of these compression springs bear against plates 24 riveted to tie plates 15, as shown in Fig. 6, or to the webs of channels 14- themselves. Apertures 25 are provided within the outer casing 10 at these points permitting springs 23 to enter and transmit pressure to channels 14. By thus flexing these channels the effective width of the magazine can be varied at will and the pressure of the feed chains against the wood controlled.

Feeder chains 9 are made up of pairs of heavy links 20 tied together by means of pins 27. These chains must be of unusually strong construction, as the total pressure which they exert upon the face of the grindstone amounts to between 45,000 and 60,000 pounds. Fixed on the inner face of each link 26, and near the lower or forward end thereof, is a spur or spike 28, the function of which is to bite into the wood and force it downwardly with the chain. The position of these spikes or spurs is very important. If they were p aced near the upper or rear ends of the downwardly moving chains they would tear and rip the wood as the chains moved away and around their lower sprockets, and this would not only increase the required power, but would shorten the life of the chains. According to this invention, these spurs are fixed to the lower or forward ends of the links. With this structure, as the chain leaves the wood and moves away around the lower sprockets, the link is pivoted at its upper end and the spur is, therefore, withdrawn from the wood in a direction substantially along its length, and is consequently withdrawn as a nail is withdrawn from a board with great ease and no tearing or ripping of the wood.

Feeder chains 9 move around fixed lower "sprockets 29 and upper idler sprockets 30.

Power is supplied to these chains from a variable speed motor 32 through the intermediary of a reducing worm gearing 33. 34; and 35. The speed of motor 32 is controlled by an automatically operated rheostat on the field coils of the motor. These rheostats may be operated, for example, by a relav controlled by the current consumed by the grindstone, and the speed of motor 32 and the movement of chains 9 may thus be made dependent upon the power consumption of the grindstone. Any speed-regulating means operated by the power consumed by the grindstone would suffice. There are many such on the market, any one of which could be used, and the mechanical details of which form no part of this invention. With a fixed, constant feed, the power consumption, when grinding small or loosely packed logs, would drop far below the minimum required for efliciency, while with large, tightly wedged logs this consumption would probably rise above 1500 horseower, and burn out the driving motor. Vith the regulatable feed of the invention, however, the speed of the feed motor varies with the character of the wood being ground, and maintains the power consump tion of the stone relatively constant.

It is common practice to supply the necessary water at the face of the grindstone with the attendant dangers disclosed above. According to this invention the water is introduced at the upper end of the magazine through pipe 36. This water is sprayed over the wood in the upper part of the magazine and trickles down through the entire mass of pulpwood until it eventually reaches the stone. In so doing it not only thoroughly saturates this wood and thus softens and prepares it for grinding, but it itself is thoroughly pre-heated having come into intimate contact with the hot vapors rising from the rinding surfaces. This contact has not only resulted in pre-heating the incoming water, but has condensed the outgoing vapors and thus conserved their heat content. The efficiencies gained by this simple expedient of introducing the water at the upper end of the magazine are as important as the idea is simple. They may be briefly reviewed as follows First, the water is preheated before coming into contact with the grindstone, and thus the danger of cracking is minimized; second, the wood is thoroughly softened before grinding and may thus be ground with a minimum of power; and, third, the sensible heat otherwise lost by the passing ofi of the vapors generated by the grinding surfaces is conserved.

lln order to compensate for the inevitable wear of the grindstone, the lower end of the magazine is provided with an adjustable pocket. This pocket comprises a casting 37 supported upon housing 4 by means of threaded bolts 38 passing through apertured lugs 39, integral with the sides of the casting. This casting may be lowered by proper manipulation of nuts 40 to which access may be had by doors 42. In order to present a substantially continuous wall, the upper edges of the casting 37 and the lower edges of the magazine proper are provided with a. series of interfitting fingers 4:3 and 44 respectively. although other means may be employed.

The frictional heat of grinding is conducted through shaft 2 to bearings 3, and often results in melting the bearing metals eeaoeo thereof, as stated above. In order to prevent this and to reduce the temperature of the shaft where it is journaled within the bearing metals, a cooling apparatus has been devised according to this invention, and is clearly shown in Figs. 3 and 4. This apparatus comprises a pair of flanged collars fixed upon the shaft 2 between the flanges 7 and bearings 3, the upstanding flanges of which are spaced apart to permit the introduction of a cooling fluid between them. Surrounding the shaft at these points, one on each side of the grindstone, but not contacting therewith, are two housings 46. In the upper halves of these housings are water chambers 47, the lower walls of which are provided with a series of small openings 48 through which water plays upon shaft 2 in the space between the collars 45. Water is constantly supplied to these chambers 47 through water pipes 49. The" water flows around shaft 2 andinto the lower half of the housing 46, from which it flows away through aperture 50. In this manner heat conducted from the grindstone along the shaft is absorbed bythe water and carried off, and this heat cannot be added to the normal heat generated within the journal boxes themselves.

The operation of the method and apparatus described above may be briefly reviewed as follows: Magazine 8 is filled with the ordinary logs which are to be ground into paper pulp; water is sprayed on these logs through pipe 36, and feed chains 8 are set in motion. Spurs 9 of these chains grip the logs along the entire length of the magazine and force them against the rotating grindstone. This force is suflicient to cause the entire column to move slowly into grinding contact with the stone and entirely overcome any tendency of the logs to arch. The grip which these chains have upon the wood may be illustrated by reversing their movement. Upon doing this it has been found that the entire column may be moved upwardly, none of the central logs dropping out. The fact that the lower end of the magazine is slightly smaller than the upper tends to increase the grip of the chains upon the wood as the latter descends and is usually sufficient for all pur oses. It sometimes happens. however, w en logs of varying shapes and sizes are being ground that they are loosely packed, and hence additional pressure should be brought to bear upon them to consolidate the column. This may be readily effected by screwing inwardly hand wheels 17 which results in bending or flexing the chain guides 14, and pressing the chains even more tightly against the wood. Meanwhile the water through pipe 36 is softening the logs and becoming pre-heated. As the grindstone wears the pocket at the lower end of the magazine is extended.

\Vith this apparatus it is never possible for the stone to race free of any load, nor be subjected to greater grinding pressure than it can well stand, for the variable speed motor 32 controls the rate of feed and maintains it as nearly uniform as is mechanically possible.

Many of the features of my invention shown and described in this application are not claimed herein, but are being claimed in my copending application, Serial No. 594,501, filed October 14, 1922, which is a continuation in part of the present case.

I claim:

1. A wood-pulp grinder of the magazine type comprising the combination of a grindstone, a magazine'adjacent to the grindstone and adapted to receive the wood to be ground, endless feed chains operating in the magazine for positively feeding the wood to the grindstone, flexible channels or guide ways in the inner walls of the magazine in which the feed chains move, and means for flexing these channels to vary the effective width of the magazine.

2. A wood-pulp grinder of the magazine type comprising the combination of a grindstone, a magazine adjacent the grindstone adapted to receive the wood to be ground, flexible channels or guide ways in the inner walls of the magazine in which feed chains move, and means for flexing these channels to vary the pressure exerted by the chains upon the wood.

' 3. A wood-pulp grinder of the magazine type comprising the combination of a grindstone, a magazine adjacent thereto adapted to receive the wood to be ground, an adj ustable pocket at the lower end of the magazine adapted to be lowered as the grindstone wears away, downwardly extending fingers on the'magazine proper. and upwardly extending fingers on the adjustable pocket, the two sets of fingers arranged to interfit and thus maintain a substantially unbroken wall when the pocket is lowered.

4. A wood-pulp grinder of the magazine type comprising the combination of a grindstone, :1 magazine adjacent to the grindstone adapted to receive the wood to be ground, a lining in the magazine, vertical slots in the lining, flexible channels or guide ways in the slots, endless feed chains operating within the magazine for positively feeding the wood to the grindstone and held within the channels or guide ways, and means for flexing these channels to vary the pressure exerted by the chains upon the wood.

5. A wood-pulp grinder of the magazine type comprising the combination of a grindstone. a magazine adjacent to the grindstone adapted to receive the wood to be ground, endless feed chains operating within the magazine for positively feeding the wood to the grindstone, and means for varying the efiective width of the magazine to conjustable pocket at the lower end of the megatrol the pressure of the feed chains against zine adapted to be lowered as the grindstone the wood. wears away, the corresponding inner faces 10 6. A wood-pulp grinder of the magazine of the magazine and pocket being substan- 5 type comprising the combination of a rindtia-lly in the same plane. stone, a magazine adjacent thereto a apted In testimony whereof I afiix my signature.

to receive the wood to be ground, and an ad- JOHN J. WARREN.

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