US225922A - Paper-pulping engine for the reduction of wood - Google Patents

Description

W.'E. FARRELL. I Paper-Pulping Engine for the Reduction of Wood,

Straw, 820.

, 2 Sheets-Sheet 1.

No. 225,922 I I PatentedMar. 30,1880.

ml HIIWL U attests F i xnx entor N.PETH\S. FNGTO-UTHOGRAPNER. WASHINGTON. D. C

2 sheets-sheet 2 W. E. FARRELL. Paper-Pulpin-g Engine for the Reduction of Wood,

Str

2 a i T Fig 3 r w. v vm NJETERS. PHOTO-UTNOGRAPHEH, WASHINGTON. D. C.

- of rolls D D.

UNITED STATES PATENT OFFICE.

WILLIAM E. FARRELL, OF PHILADELPHIA, PENNSYLVANIA.

PAPER-PULPlNG ENGINE FOR THE REDUCTION OF WOOD, STRAW, &c.

SPECIFICATION forming part of Letters Patent No. 225,922, dated March 30, 1880, Application filed January 7, 1880.

To all whom it may concern Be it known that I, WILLIAM E. FARRELL, of the city and county of Philadelphia, State of Pennsylvania, have invented certain new and useful Improvements in Paper-Pulping Engines for the Reduction of Wood, Straw, Jute, Rags, Manila, and other Vegetable Fibers to PaperPulp; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the annexed drawings, making part hereof.

In United States Letters Patent No. 215,7 28, which were granted me under date of May 27, 1879, for a process for reducing wood and other vegetable fibers to paper, also for an application for Letters Patent for an improved process on that described in said Patent No. 215,728, which application was allowed November 11, 1879, I described various mechanical ways by the employment of which I could practice the process therein described.

Many and various experiments made before and since the patent and application above alluded to have resulted in the herein described paper-pulping engine.

In the drawings, Figure 1 is a perspective view of my device; Fig. 2, an elevation, partly sectional, having part of the pan cut away to show the intended arrangement; Fig. 3, a plan view, with the raising and lowering mechanism and its support removed in order to more clearly show the interior; Fig. 4., a cross-section of the gate and side screen on the line X X of Fig. 3.

A is a circular pan, flaring outwardly from the bottom toward the upper edge; B, a central frustum of a cone, pierced to receive the upright shaft 0. Between this cone and the sides of the pan is a circular annular space, in which the rolls or crushers D D traverse.

E E are roll-scrapers to remove particles of wood and pulp from the crushing-surfaces F F F are wire side screens. G Gr G are dam-boards, to prevent the water or solution within the pan from flowing out at the valves I I I until it is desired to run itoff, when they can be raised to release it. E H are the spaces between the screens and damboards; H H, spaces between the gates and the continuation J of the sides of pan A. Be-

neath these latter openings are the valves I I ties.

I, to permit the final escape of the liquor from the pan A.

J is a bulged continuation of sides A, to inclose the recess occupied by the gates or damboards and the valves. K L is a frame-work or casing to receive and support the screens F. M M are two slots in the opposite sides of the frame or box 0.

O is the square shaft which carries the rolls D D upon its opposite round extremi These rolls are loosely set upon the round ends of shaft 0, so as to turn freely thereon. Shaft 0 does not turn with the rolls, but is secured in open vertical slots in the box 0, and revolves in a horizontal plane with box 0 around its junction with the upright shaft (J as a center. As it revolves it carries the rolls D D around with it, as they are secured loosely upon its extremities. The shaft 0 is hinged at 0, so as to permit that end of the shaft to rise up if the roll D in its traverse has to climb over a lump or obstacle. A similar joint may be set near to the roll D for a like reason.

The box 0 is rigidly attached to the top of the main shaft 0, which is set in abearing, B, and is turned by a pulley, G", upon its lower extremity. The box 0 and shaft 0 have no vertical movement, but simply turn with each other. The pulley C may be dispensed with and a cog-wheel may be used in its place.

I? P are two pins passing from the shaft 0, one on each side, through the slots M M, whereby, as shaft 0 is raised and lowered, it is guided in a vertical plane and lateral move.- ment is prevented.

N N N N are chains attached to cross-bar N, to support and raise and lower the rolls D and D. They are attached as shown in Figs. 1 and 2. i

Q is a side sweep or agitator in the annular space in the pan, which sweep, in practice, will be wide enough in the blade. to sweep that portion of the said space extending all around and as wide as from any point at the sides to about three-fifths of the way across to the cone at the center.

R is a similar sweep or agitator, to sweep a space in width from the center cone to about three-fifths of the way to the sides, so that the spaces traversed by these sweeps slightly over- 2 EQiQQQ lap. The sweep Q follows the roll D, and throws the material which that roll has passed over into the space to be traversed by the following roll D, and the sweep R, which follows the roll D, throws the material thus acted upon by the last-named roll back to the space about to be traversed by the following roll D, and thus the operation is continued.

S S are wedges in the screen and gate frames to hold the screens and gates in their places; T, a loose ring-bolt, attached below to the bar N, from which are suspended four chains,N N N N, each poising to a stationary flange or collar upon the shaft or axle O. The head of the ring-bolt Tis in box U. The bolt being smaller than the hole in the bottom of box U will turn freely therein. The box U is secured rigidly to the threaded bar or rod V, which has only a vertical motion as it is raised or lowered by the threaded wheel W, as the thread of the latter operates when the wheel is. turned. The bar V passes through the threaded axle-hole of wheel W. X is a horizontal shaft, turned by a crank, Y, at one end, and at the other terminating in a beveled pinion, X. The cog W has a bearing upon frame Z, and the shaft X is mounted in bearings upon the same frame.

The roll D is situated nearer to the outer wall of the pan A than roll D. The circular spaces traversed by each roll slightly overlap, like that traversed by the sweeps Q B, so that the stock will not only be agitated but acted upon by the "arious rollsin succession.

Z is a steam-tigl'lt removable shell of boileriron, covering the whole machine.

The shaft of crank Y passes, in practice, through a stuffing-box through the shell, and by detaching the crank the shell can be lifted off. The shell has a man-hole above, through which material can be passed in and out; but I prefer to remove the product as is hereinafter described.

The pan A is first charged with the amount of stock of cut wood to be made into pulp, the rolls 0 having been raised up from and clear of the bottom, so that the stock can be distributed over the bottom of the pan. This latter is accomplished by turning the crank Y. This revolves the cog NV, and, by means of the threaded rod V, the cog W will raise box 7 and axle O, and consequently the rolls D D, which are located upon said axle. After the stock is placed in the pan or tank the rolls are lowered until their whole weight presses upon it, or they may be kept at any requisite height to attain any desired pressure. The water or alkaline liquor is then run into the pan upon the stock. Power is then applied to turn the pulley O. This will turn shaft 0, and will. revolve axle 0 upon its middle bearing-point upon the top of cone B, (if it rests upon it,) or around the middle of the axle. As the axle turns in a horizontal plane the wheels or crushers D D revolve and crush the material under them, and the revolution is sustained until the fibers beneath the crushers attain the desired degree of fineness.

The liquor can be drawn off from time to time during the operation, if desired, and be replaced by fresh liquor.

The action of this operation upon the soaked vegetable fiber is first to crush and expel the moisture and part of the intercellulose mate rial, then to allow it to expand and reabsorb its complement of the liquor, then to crush it again and re-expel the liquor and an additional quantity of intercellulose. This operation is repeated until the fiber is well pulped, and all, or nearly all, the intercellulose is ex pelled. The fibers will then be found to be fine, long, and well separated, and not short and broken up.

If it is desired to carry on the whole pulping operation in my machine, and to boil the fiber under pressure, as well as to crush it therein, the shell Z is placed over the machine, and all the joints are well secured and tightened, and after placing the material and alkaline solution in the combined crusher and digester thus formed, the digester is then heated by any of the devices now well known in the art of pulping fibers, and power is applied to turn crank Y.

The operation of the crushers will be found to be the same as is above described, while at the same time the vegetable material will be being boiled in an alkaline solution under pressure, which combined operation will soon reduce the fiber.

If desired, the application of steam-pressure can be withheld until the crushers have some what reduced the material. The pressure can then be put on and the operation continued to its conclusion.

Other pulping-engines have required the pulp to be chemically treated previously to its being subjected to them to be crushed; but

by my plan the material can be placed into the machine in its raw state. I can use two or more rolls or crushers, if desired.

Heretofore pulping-engines have either employed revolving knives or fly-bars, or knives that are stationary, commonly called "bedknives, one or both of which accomplish the pulping by cutting, tearing, rasping, or otherwise breaking up the material, which course of treatment greatly shortens the natural lengths of the fibers and makes them unequal and short in comparison with their originallen gths. Asa consequence the shortest fibers are lost by be ing washed away, and a diminished yield is obtained, and the resultant paper is weak, in consequence of the unequal lengths of the fibers and their shortness.

The work of disintegration is done by my engine by pressing or squeezing the material to be pulped between plain or smooth surfaces.

Heretofore pulping-engines have required a great amount of skill, time, care, and attention from the attendant to see that the pulp IIO is well stirred, and not allowed either to float on the top of the water, or sink to the bottom,

or lodge in corners, or settle, and thus escape the action of the knives, and thus make short and unequal lengths of fiber. The scrapers or agitators Q R automatically mix, stir, and continually change the position of all the particles of the pulp, and my engine requires no attention from the operator in this respect.

A serious fault in the old cylinder-washer and others is, that while the cylinder is only partially submerged, the heavy dirt being near the bottom of the engine, escapes the washer entirely, and much time is lost by re ducing this heavy dirt to such small particles that they will be held in suspension by the water, so as to float to the top, and there come in contact with the cylinder and pass away.

My engine has the washing-screens at the sides, and they extend from the top, or within a few inches of the top, to the bottom, and .far enough below the bottom to effectually drain the entire engine, if it is required.

In case of very dirty stock being used, and it is desired to greatly economize the time of washing, the entire sides of the engine can be made into washing-screens F F, instead of, as

shown in the drawings, about one-fourth this space.

The washing parts are parts of the machine, and are attached thereto, and are of simple construction, and all the dirty water passes away from the pulp automatically by gravity, or with the dirt, which it holds in suspension out at the sides, and all complicated mechanism is dispensed with.

The weight of my rolls is supported by and bears directly upon the material to be pulped, and their bearing-surfaces may be corrugated on their crushing-surfaces, and the rolls revolve at the very slow speed of from five to ten revolutions a. minute; consequently at a very small expenditure of power for the work done in comparison with the engines now in use.

Much power is wasted in the old engines through the necessity of elevating all the stock by the roll (the knives on its circumference acting the same as the buckets on a push-back water-wheel) over and past the back-fall, so that its higher elevation will maintain a circulation by flowing to the lowest point in front of the roll. My engine requires no such expenditure of power to maintain a perfect circulation, which is done by the rolls themselves in combination with the scrapers.

In my engine the action of the rolls on the stock to be pulped is such that the largest particles of stock, or those requiring the most disintegration, receive at all times the first and greatest pressure or action of the rolls, while the smaller fibers escape for the time, so that in time they are practically all alike and retain nearly their full natural length and thickness, and are not cut up small or short.

All the working parts of my engine are plainly visible to the eye of'the attendant, when, as is usual, I have it open at the top, and any faulty working of any of the parts can be promptly corrected.

The sides of pan A flare or incline outward, and the conical form of the block B makes the space traversed by the crushers D D narrower at the bottom than it is at the top. This form of the pan prevents the pushing of the pulp ahead of the rolls in elevated waves, and gradually forces the stock under the rolls.

The pan may be made of wood or metal, or a combination of them. If of wood, there should be a metal bed-plate or track, on which the rolls may travel; for, where wood is used for the bottom and chemicals are employed, the effectiveness of the rolls or crushers is in time partially inj uriously affected by the yielding of the saturated wooden pan. So, to overcome this defect, the cone B and bottom of the pan may be of cast-iron, in one piece, and the sides of wood or light boiler-iron; but, as it is desirable to have solidity and durability, I prefer to have the whole pan, cone, sides, bottom, and offsets for the washing apparatus, with the posts for the same, and spaces for the emptying-valves, all of one solid piece of cast-iron, although for very large en gines-say over ten feet in diameteritis advisable for convenience in transportation to have the pan cast in sections; but as the inner cone, B, has to support the journal or step, or both, of the upright shaft (J, and has to sustain the thrust of this shaft on all sides, the bottom and cone at least should, if possible, be of one piece of metal, of cast-iron; or, if of wrought-iron, the parts should be well and rigidly secured together.

If strong acids or concentrated or caustic solution are to be used, it will be best to galvanize the iron surfaces of the engine, or, as far as practical, make it of brass, copper, lead, or any other metal or material that will resist the action of these acid solutions.

The pan A is shown as stationary, and is designed to be secured firmly to a rigid foundation by heavy bolts, having the rolls D D revolve on the bottom around the upright shaft C. It would not depart from the spirit of my invention to have the crushers D remain fixed in adjustable bearings and the pan revolve; but I prefer the form which I have shown. Those portions of the bottom of the pan which are not covered by the rolls D D in their traverse may be utilized by the usual sand-tr )S for collecting sand, dirt, grit, &c., and can .constructed in the usual manner, which, with some slight modifications of details, is the same in all pulp-engines, and for that reason not here shown. I have tried corrugated or fluted-shaped bed-plates in the bottom of the pan, to conform to similar corrugations in the rolls, but find that corrugated surfaces, whether in the rolls or bottom, separate or together, are not as good in practice as smooth surfaces.

exact weight desired.

The crushers, rolls, or compressors D D may be of any number from one to four, or more but I preferv two only, as they balance each other, while more rolls would occupy too much of that space in the pan which would otherwise be used for pulp. Although the increased number of rolls would in a great degree hasten the pulping, the diminished space to hold the stock would necessitate much loss of time in the frequent emptying and supplying of stock. I find, practically, that two rolls give the best results.

The rolls D D may be of any material to answer the purposewood, stone, or metal, or wooden frames with metal faces; but I much prefer them made of cast-iron, all in one piece. For small machines they may be cast solid. When they are intended to be used for the reduction of strong raw fibers, as a preliminary stage in the reduction of the latter to fine pulp, the sides may be convex, having a small bearing-surface, the thickness gradually increasing to the center. This gives great weight on the face in proportion to the width of rolls. When used on more, tender stock, or stock previously prepared by the usual chemical treatment, the sides may be concave, and for the shortest and most tender fiberssuch as straw and old papers-they may have a broad face, spokes, and a hub similar to an ordinary pulley. This form diminishes the weight and at thesame time increases the bearin g-surfaces.

For an ordinary use I prefer the rolls, as shown, with sides at right angles with the journal and faces cast in one piece and hollow excepting at the journals. The kind of work which is to be done by the machine will determine the width of face, the thickness of the same, as also the shape and construction of the sides, and consequently the weight or pressure of the rolls to the square inch.

In calculating the weight it is well to err on the lighter side, for if this rule be followed the hollow interior, if it is desired to increase the weight, can be either built up with cement through man-holes in the ends, or, what is better, water (made alkaline to prevent rusting the insides) can be run into the interior. The quantity of water can be increased or diminished until practical tests ascertain the Then the man-hole can be closed permanently. The core-holes and blow-holes of the casting make the man-holes, which are finished flush with the ends.

I prefer not to use the castings in their rough state; but I plane and finish the two ends and face of the roll with a true smooth polished surface, and round off the edges of the face of the rolls, so as to prevent any sharp edge coming in contact with the fibers to be pulped.

In my applications above named I mentioned corrugated or fluted faces and cone-shaped rolls but I prefer them plain and with the face at right angles with the ends, as shown; for the twisting motion of the straight rolls, though avoided by the cone-shaped rolls, is not objectionable, except in pulping very short and tender fibers with heavy rolls. In corrugated surfaces the pulp becomes lodged in the grooves, and thorough action of the roll-scrapers E E is thereby prevented, and so uniform pulping is defeated to a greater or less extent.

By a well-known law of mechanics the larger the diameter of a wheel the less power is required to move a given load supported by it; so I prefer my rolls to be as large as the space to be traversed and the weight and material to be pulped will allow. Rolls from five to eight feet in diameter are good for woodeven those of ten feet are better. Another advantage of large rolls is, that the sharp pinch or nips of small rolls is avoided, which may cut the fibers.

The removal from the stock of all dirt and inter-cellulose matter is termed washing. This is accomplished by the wire screens F, dam-boards G, spaces behind both, H H, and the valves I I I, which are inclosed in the eX- tension of the sides of the pan A, as shown. This washing is performed with the greatest simplicity in my engine, and is accomplished through the gravity of the particles of dust. Clean water is let into the pan and saturates the stock. The rolls press out the dirty water and intercellular matter while they are pressing the stock. The dirtis then held in the water in suspension, the dam-boards G are then raised or taken out altogether, and the dirty water from the top to bottom flows through the screens F and out of valves I. The wire screens keep back the clean fibers, and the side agitator or scraper, Q, removes with each revolution any accumulation of fibers which collect on the face of the wire screens I The bottom of the offset J is an extension of the bottom of the pan A, only it is on a level low enough to allow all the water and pulp in pan A to flow by gravityover the frames of screens E. When the stock is clean,the water is stopped in its flow into the pan A, the valves I are closed, and the dam-boards G put back and wedged into their places by wooden wedges, and the pulping of the now clean stock is continued.

If very dirty stock is used and it is desired to greatly hasten the washing, the whole side can be made into screening-surface, instead of about one-fourth, as shown. The extension J of the sides of the pan A need only be enough to allow for the wire screens F, dam-boards G, and valves I, and to allow of their proper working, as described, and this will permit the pan A to be cast in one piece.

The posts K and the rims L, which latter are continuations of the true side of the pan A, form, with the bottom, a frame, against which the frames of the wire screens F are pressed by wooden wedges S, which, with the screens and dam-boards, fill up wedge-shaped grooves formed by rims L in the sides of the pan and in posts K.

The dam-boards G are simply solid wooden movable partitions working in their grooves, and held to their places by wooden wedges S, and act as a movable or temporary false side to pan Q. When the pulp-stock is completed and it is desired to empty the engine, the wedge to the wire screen is taken out. The wire screen is then removed or raised, the dam-board is simil arly treated, an d one of the valves is raised. This will permit the whole of the pulp to flow out of the engine.

When I have a steam-tight shell over my engine, an opening or side manhole may be left in its side opposite the dam-boards, and this opening can be covered so as to besteamtight during the boilingof the stock. I can fit a steam cup or jacket in the usual way over my pan with a steam-tight joint.

In washing, all the dam-boards may be up and all the screens in; but in. emptying one screen and only one dam-board require to be removed.

The upright drivin g-sh aft 0 has, at its upper end, a head, 0, with two slots, Maud M, cut at right angles to each other. Mreceives the shaft 0, which conveys power from upright shaft G, by means of head 0, to the rolls D D, while M receives the pins P P, to prevent lateral movement of the shaft. The rollsD are secured in position by any of the" Well-known devices; but the boXes or journals for the shaft 0 in the axes of rolls D are fitted with stuffing-boxes (not shown) or caps, so as to prevent the drip of oil or grease into the clean stock. r

The roll-shaft O rises and falls in slot M, so

as to accommodate itself to any rise or fall of the rolls D D in passing over any irregularities in the height of the stock being acted upon by the surface of the rolls D D, or to roll over any foreign obstructions which may have fallen into the pan or stock, any of which would otherwise break the machine in some of its parts if the shaft 0 were rigidly fixed to the head of the upright shaft 0.

The valves I can be used variously for washwater, half-stuff, unbleached or bleached pulp, and their respective uses maybe duly marked on them to prevent mistakes.

Though I have described the motion as being communicated to shaft 0 from below by a pulley and belt, I prefer a large bevel-wheel and small pinion, which give a slow motion, with the power well and simply applied. In places where it is inconvenient to drive from below, the power may, by any of the usual forms, be communicated from above. The cone B then becomes, in place of a journal only, a

journal and step combined, and the shaft 0 is reversed, or is carried above the head 0 to meet the journal and driving-power above. When it is driven from below the usual step receives the lower end of shaft 0.

The arms, scrapers, or agitators Q B may be made so as to be adjustable by having part of each arm slide upon the other part. The advantage of securing these scrapers to the head 0, as shown, is, that as the shaft 0 and head of the same, 0, maintain a uniform level and do not rise and fall with the rolls D D or shaft 0, they maintain their position at all times.

The roll-scrapers E are attached to shaft 0, and rise and fall with it and the rolls D. These roll-scrapers are adjustable blades that bear slightly on the faces and ends of rolls D D, removing from these rolls any stock that may adhere to them, and which would otherwise be carried around on them. The stock thus clinging to the rolls, if on their faces, would receive too much crushing, and if on the sides too little.

As in the course of time the scrapers wear down by being in constant contact with the rolls, they may be set up to their places by any of the ordinary ways known in mechanics. The stock when first treated will bear harsher crushing than when wholly or partially disintegrated, and if the rolls are only just heavy enough to perform the latter part of the process properly, much valuable time may be lost in the beginning of the pulping through the. rolls being too light. I prefer to start with a roll heavy enough to do the breaking in or preliminary disintegration, and, by means of suitable mechanism, raise the rolls from the stock gradually. Consequently I thus lessen the pressure of the rolls on the fibers until the rolls, if necessary, do not impinge on the bottom of the pan at all. If the engine is driven from above, I place the foot of the upright shaft 0 in a movable step, which can elevate the head 0, and with it the shaft 0 and the rolls D D. If driven from below, as shown, I employ the chains N N, the swivelbox U, screw-rod V, bevel-wheel W, and pinion X, rod X, crank Y, and its supports, and beam or frame Z.

To accomplish the result desired the screwrod, bevel-wheel, and pinion may be replaced by a lever like a scale-beam with a sliding weight, or any other of the well-known devices in general use may be used to raise the rolls, as shown; but by the means above described the economizing of power is so great that a few pounds weight on crank Y will raise the heaviest rolls, and as this action on the rolls is so slow, the rolls can be graduated in height to such a delicate point as to make variations of one-five-thousandth of an inch or less, which is not possible in any other engine. If driven from below, this same delicate adjustment can be applied to the step in which rests the lower end of the shaft 0.

When I do not inclose my engine in a steam dome or jacket, but leave it open, I proceed as follows:

For pulping wood, esparto, jute, straw, and such stock which has not been subjected to any previous treatment, but is in its natural condition as received in the paper-mill, I first cut it into suitable lengths, (and it may be air-dry or previously soaked in hot or cold water or an alkaline solution, hot or cold, in open air or under pressure.) I then add. the

stock gradually to the hot liquor in the pan IIS as the rolls revolve. When the fibers have been relieved from the pressure of the crushers they are comparatively dry and porous, and expand, returning to nearly their original position. In thus expanding, the fibers begin to separate from each other and the intercellulose matter, as they are not so firmly held together, owing to an increase of the spaces between the fibers, caused by the displacement of all the particles, the increased elasticity of the fibers, and the absence of some of the intercellulose matter which was displaced by the first compression and passed away from the fibers. This intercellulose matter, held in suspension by the liquor, is forced out of the fibers, and their cohesiveness is destroyed. This process of alternate pressure and expansion of the fibers has the effect of finally reducing the stock into separate fibers.

When the liquid is thick with intercellulose matter the dam-boards G are raised, the valves I opened, and the liquid runs to waste, carrying with it the impurities of the stock. If for cheap paper. this much of the process will leave the stock clean enough, and the stock may then be pulped to the fineness desired. If fine white paper is required, the washing may be repeated one or more times until absolutely pure fibers are obtained, when the usual manipulations known to the art-such as bleaching, brushing, sonr-bleachin g, sizing, &c.-can be continued.

For the first washing I prefer hot water alone but if the stock develops strong acid tests I use lime-water or other alkaline liquor to neutralize the acids in case the engine is of iron and the acids in the stock are likely to attack the iron and eventually discolor the fine pulp for fine white papers with a trace of iron. If hot water alone or lime water will not remove the intercellulose, I then wash them out, and to the now finely-disintegrated and nearly-cleansed pulp I add a second bath of alkaline solution and continue the process. When the alkaline solution has thoroughly acted it is drained off, and may be recovered by evaporation and incineration. The traces of alkali are washed out with clear water, and the now pure fibers are treated as usual.

In cases where stock has been previouslytreated by any of the many well-known processes I simply wash, as stated, with clear water, hot or cold, and when clean pulp is used by compression of the rolls, as already described, to the degree of fineness required,'and the subsequent treatment is as required.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a pulp-engine, the combination of pan A, central step or block, B, and revolving selfadjusting rolls D D, substantially as and for the purposes described.

2. In a pulp-engine, the combination of pan A, central step or block, B, revolving self-adjusting rolls D D, and automatic scrapers or agitators Q R, substantially as described.

3. In a pulp-engine, the combination of pan A, cental step or block, B, revolving self-adjusting rolls D D, and central box, 0, slotted to permit upward and downward movement of the axle O, substantially as described.

4. In a pulp-engine, the combination of pan A, central shaft, (J, revolving adjustable rolls D D and the raising and lowering mechanism N, N, T, U, V, W, X, and Y, whereby the height of the rolls from the bottom of pan A can be adjusted or regulated, substantially as described.

5. In a pulpengine, the combination of crushers D D, pan A, and the screens F and dam-board slides G, whereby the pan can either be drained of its liquor or cleared of its product, or both, substantially as described.

6. In an engine forcrushin g vegetable fiber, the combination of pan A, revolving crushers D D, and the shaft 0, hinged at 0, whereby the raising up of one crusher while passing over a lump or obstacle will not affect the position of the other, substantially as described.

7. In a pulp-engine, the combination of pan A, crushers D D, shaft 0, and the enveloping shell Z, substantially as shown, whereby the operations of crushing vegetable fiber and of boiling it under pressure can be carried on in the same apparatus, either simultaneously or successively, substantially as described.

8. In combination with the pan or shell of a pulp-engine, the crushers D D and the offset J in said shell, whereby the draining device and exit-trap for the stock are set out of the line of traverse of the crushers and scrapers, substantially as described.

9. In a pulp-engine, the combination of pan A, revolving crushers .l) D, and agitators or stirrers Q, It, the latter being so arranged that each one throws the material lately acted upon by its preceding crusher in front of the next crusher, whereby the stock is distributed and evenly acted upon, substantially as described.

10. In a pulp-engine, the combination of pan A, revolving crushers D D, axle O, and a revolving central shaft, 0, having a doubly-slotted head or terminus, 0, one slot to receive the axleO and the other a pin or pins, P, upon the same, to prevent lateral movement of the axle, substantially as described.

WM. E. FARRELL.

Witnesses:

GEO. E. BUOKLEY, 0. W. GREEN.

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