US122181A - Improvement in machines and processes for manufacture of peat fuel - Google Patents

Description

Patented Dec. 26, 187.

UNITED Si'rA'rns is worked.

Pn'rniwrC OFFICE.

THOMAS H. LEAVITT, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN MACHINES AND PROCESSES FDR MANUFACTURE 0F PEAT FUEL.

V Specification forming part of Letters Patent No. 122,181, dated December 26, 1871; antedated December 20, 1871.

To all whom it 'may concern:

`Be it known that I, THOMAS H. LEAVITT, of Boston, in the county of Suifolk and State-of Massachusetts, have invented Improvements in the Manufacture of Peat Fuel; and I do hereby declare that the following, taken in connection with the drawing which accompanies and forms part of this specication, is a description of my invention sufficient to enable those skilled in the art to practice it.

My invention relates to a new process of manufacture for the conversion of crude bog-peat into a hard, dense, and dry fuel; to an organiza- .tionof mechanism by which this process, to a greater or less extent, is practiced; to the details of mechanical appliances used in such machine and process 5 and to the composition of such fuel.

In my improved process for converting wet spongy bog-peat into hard, dry, and solid fuel I iirst take the crude peat and, by suitable mechanism, express therefrom a part of the water contained in it. I then subdivide and knead the compressed peat, and after a continuous kneading operation I again compress the peat in suitable molds, by which last operation the peat is formed into blocks'of suitable shape for fuel and ready for a nal drying operation in the sun and air or in suitable buildings or dry-houses. It is in this process that my invention primarily consists. ing with said process of treatment the injection of steam into the lnass of peat being kneaded, and the treatm'ent of such mass by the projection upon or thereinto of atomized liquid or liquid spray or powder. The invention further consists in combining with the kneaded mass, either in the process of working it or subsequently thereto, extraneous fibrous materiallike shavings, dried grass, straw, or other similar fibrous material-as also in combining with peat extraneous iniiainmable substances, like oil or resin. The invention also consists in combining with the triturating and kneadin g m echanism a heater, cylinder, or case, over and around which the peat Also, in the details of combination of the various mechanical devices to be hereinafter explained.

Itis well known that peatisdecmposed or partially-decomposed vegetable matter, generally occurrin g in moist localities, where the growth consists mainly of messes, rushes, iags, coarse grasses, Ste., in many cases of very rank growth. As

excavated from the bog it has the appearance ofV The invention further consists in combina tubular cellular mass of mud, generally dark brown or black in color, the cells being principally formed by the straw-like remains of the stems and stocks of the rushes, grasses, 8vo., of which it has been formed from year to year, these cells (or tubes, as they are in many cases) comprising a very considerable portion of the bulk of the mass, and being lled either with water or air. If allowed to dry in precisely the condition in which it is cut from the bog, i. e., with its structure undisturbed, the mass will generally retain its form, in some cases with a good degree of strength and solidity, while in other cases it will be found to be exceedingly friable, and so loose in texture as hardly to bear handling.

Peats, although possessing the same general features, differ in structure and characteristics as much as the different varieties of wood and coal. If, without other treatment, pressure be applied to almost any of the varieties of peat, as has often been attempted for the purpose of extracting water and solidifying it, the peat, when dried, will be found much more friable than if dried in its natural state, as cut from the bog,

Without pressure. Peat has been used for fuel for centuries, generally in the-condition first above mentioned-t1 e., simply cut from thebog in blocks or masses of convenient size and dried. But during the last fty years numerous attempts have been made to prepare it in some better manner, the aim generally being to solidify it, and that for two principal reasons, viz.: First, in order to produce a more dense and harder fuel, which should be more enduring in service and capable of bei'n g employed in manufactures and the arts and elsewhere where a soft or light fuel would be entirely unfit for the service required. Second, so that it might be so reduced in bulk as to admit of transportation as an article of traffic. To`

this end various means have been devised and various machines more or less elaborate have been constructed, but operationsthus far are all resolved into one of three methods, viz.: First, to place the material just as it comes from the bog under powerful pressure, for the double purpose of extracting the water and compressing the mass. l

Second, to dry and disintegrate the material, and in that condition to compress it into blocks of convenient sizefor use. Third, to work or temper the mass, in the moist condition in which it is taken from the bog, until it is reduced to a somewhat uniform degree of consistency, nmany cases introducing into the mass an additional even more closely in those cells, and the pressure applied takes 'effect only on this air, which is the only elastic or compressible portion of the mass, the solid matter and the rater being alike incapable of compression; and the consequence is,

that if pressed in atight box or 1nold,on removing the pressure the air-cells again expand and the mass resumes nearly its original dimensions, and, when dried, is found lto be still porous, and even more friable than when dried without having been submitted to pressure. The reason for this I do not pretend to give, but I speak of the fact as demonstrated in my own experience. Again, if pressed in other than tight molds or boxes, any openings intended to allow the water or air to escape have been found to furnish as free passage for the peat also, so that the water and air must necessarily be retained under pressure; or, if allowed to pass out, it was with a certainty that the peat would follow and, therefore, no satisfactory results could be obtained. Ihe second method involves the necessity of expensive and very powerful machinery. The product in some cases has been very hard and generally attractive in appearance, but the material of which it is composed being dry, and neither plastic nor adhesive, the particles are compacted only by force of mechanical pressure, and the blocks, when placed either in water or on the fire, become quickly and finely disintegrated, so that the fuel is likely to be spoiled and rendered entirely unfit for use by exposure to rain, and is practically useless for many of the purposes for which fuel is required from lack of cohesion, or the fact of its rapid disintegration while burning.. rIlhe process has, in all cascs, proved to be too expensive to warrant its use, and is now, I believe, entirely discarded both in this countryand in Europe. The third method, under various modifications, is the one now generally in use, and produces by far the best fuel of either ofthe three methods, It is applicable to nearly all the varieties of peat, and produces afuel having strength and solidity to a degree which is not obtained by either of the other methods. There are, however, difliculties attendant upon it which all acknowledge, and which it is desirable to overcome, the principal of which is that in this method of treatment, as generally pursued, there is an amount of Water varying from seventy to ninety per cent. of the whole weight, which must be handled and moved through all the course of treatment, involving, of course, corresponding expense for labor, and which heretofore it has been found mpracticable to eject or remove is such that it has battled all attempts to separate themv by any mech anical means heretofore known, and it has been my purpose to devise a'process and the necessary mechanical appliances to put it in operation, by which the advantages of this third method should be retained and its difficulties overcome, so as to produce a fuel possessing strength and cohesion capable of being charred Without disintegration, and which, for domestic purposes and in manufactures and the arts, should possess the properties requisite for its successful use in all these cases. And it has been my aim, too, to produce machinery for manufacturing it which should be of a character to be easily managed and capa-ble of turning out large quantities in good merchantable shape and at moderate cost.

In my process the crude peat, just as it is cut from the bog-its structure being very nearly in an undisturbed condition-is submitted to pressu're in such manner (hereafter described) as to extract a considerable portion of the water contained in its cells. Itis then brought under the action of knives so aste cut up finely any sticks, roots, or bers which might otherwise accumulate in the mill and tend to clog its operation. After this the mass is very thoroughly Worked, by

a rubbing or other process, for the purpose of still further breaking up the original structure ofthe mass and ejecting from the tubes and cells so broken up the air which is contained in them, leaving nothing but the solid matter in moist condition. The same treatment is continued for the purpose of drawing out, laminating, and packing the particles and minute fibers of the mass and developing certain plastic and adhesiveproperties, which, until such treatment, appear to be,

to a certain extent, latent.

Although a prime object is to extract a considerable portion ofthe water, it must be understood that a considerable amount of moisture is V necessary during treatment in order to insure cohesion of the peat when4 formed into blocks, and a large amount of Water having been extracted by the operation rst alluded to, its place may be supplied during the rubbing process by one or more jets of steam, admitted or forced into the mass under pressure while the mass is being kneaded; and it is found that a very small quantity of water, in the form of steam, so injected, serves the purpose equally well as the larger amount which has previously been extracted,

and has the further advantage of imparting heat to the mass, which, at a subsequent stage-that is, after the peat so prepared has been molded and exposed to dry-has the eifeet to promote, to a very perceptible degree, the process of evaporation, inasmuch as evaporation'will commence more quickly and proceed more rapidly from a heated mass than from the same mass in a cold state. And it is also demonstrated that the scaldance,

ing or cooking of the peat consequent upon the admission of hot steam tends to the-more perfect development of its plastic and adhesive properties, and yields as a result a stronger and less .friable fuel. If practicable, the mass at this stage should be still further hea-ted, cooked, or scalded, or brought to a high temperature, but Without increasing the amount of moisture above what is absolutely necessary1 to insure its cohesion when formed into blocks. In this condition it may be molded or formed into blocks of any size or form in any convenient manner, and either with or without being again exposed to pressure, in manner similar to that first mentioned, for Vthe purpose of extracting a further amount of moisture and of giving the blocks more compact and perfect forms. The blocks so produced may then be laid away to dry either in the open air or in suitable dry-houses, the heat imparted to them in the process of manipulation operating as an active agent in promoting rapidly the process of evaporation. At this stage the material bears somewhat the same relation to the dry fuel that green wood does to dry wood, and the process of drying or curing in both appears to be similar; but theresult obtained by this process is peculiar in thft as the peat so prepared dries it assumes a mineral-like hardness and appearand breaks with a fracture not unlike coal or stone, and can never again be dissolved in water or reduced to a plastic mass; its characteristics having been entirely changed, partly by the treatment I have described and partly by chemical action (apparently in the nature of carbonizin g) consequent upon that treatment( One essential advantage in the economy of labor gained by this process is apparent, for whereas the average percentage of water contained in peats as ordinarily excavated and brought to the mill for treatment is seventy-five per centnone of which, by any former process, is actually extracted during the vtreatment-many persons choosing rather to add more water to it--and the same has, therefore, to be handled and carried away again after treatment in the mill-by this process a very considerable percentage of the water is extracted and passes off, and the labor required to remove and handle the manufactured product is, therefore, reduced by the weight of water taken out.

rlhe drawing represents a machine embodying my improvements in peat-treating mechanism.

A shows the machine in sectional elevation taken on the line x B is an end elevation. C is a sectional plan taken on the line z z.

a. a denote two stands or uprights, connected by suitable cross-beams, and having mounted upon `them a strong frame-work, b, which, with side plates c extending from post to post b, forms the casing of a mill, in which the peat undergoes that treatment which prepares it for the fina-l compressing and molding operation in the block-forming molds. Extending centrally through the mill is a vertical shaft, d, rotating in suitable bearings, and having at its top a bevel-gear driven by a gear, e. on a horizontal shaft, f, rotating in suit- At the able bearings at the top of the machine.

top of the mill is a horizontal plate or table, g, upon which the crude peat is received, this plate extending half way across the mill, as seen at A, and having an edge-flange, h, which extends to the circumference of a rotary cylinder, t, the axis of which turns in suitable journal-boxes on the frame b, the hopper-space over the mill opening to the top of this cylinder, as seen atA. Around the rear and under the cylinder is aperforated plate, lc. Inthe cylinder t' are mold-spaces Z extending from end to end of the cylinder and radially into it from the cylinder-face, and working in each mold-space is a plunger, m. By a suitable cam mechanism each plunger is carried to the bottom of its mold when the mold is approaching the` upper part of the mill, and the mold is then open and in condition to receive the peat, which is swept into it from the plate g by suitable inclined blades, sweeps, or arms n'proiecting from the shaft d; these arms not only sweeping the crude peat from the plate g into the space over the cylinder, but pressing it down into each mold as the mold comes into position. As the filled mold moves on it comes to the perforated plate 7s, and the cam mechanism then moves the plunger outw ard, compressing the peat against the plate la and expressing water therefrom, the water escaping through the perforations of the plate. The plun gers may also be perforated to allow the expressed water toescape'througr the plungers as well as through the plate k. The expressed water may be led off through any suit able ducts or conductors. After each mold ha: passed its lowest position, and by the contiguou: plate lc, the cam mechanism throws the plunge: still further out and causes it to eject the peat The compressed blocks of peat ejected from thi cylinder 'i are pushed along untileach reache,` and passes over a bar, o, against or in juxtapo sition with the outer edge of which rotates z knife or cutter, p, extending between two heads g, which are mounted on a rotary horizontal shaft r, driven by a band, s, extending around a puf ley upon said shaft and another pulley on th shaft j', the rapid' rotation of the knife cutting u the peat, which falls from the cutter down upo a plate or shelf, t, which plate or shelf is the u; per one of aA tier or series of horizontal shelve: t 'u t w, over and rotating closely against the to surface of each of which are arms or spatula blades or sweeps extendingv radially from th vertical shaft d. In each of these shelves a opening, y, is left on one side, and through th opening the peat falls to the shelf below. Tl peat upon the upper plate t is worked by the 1'- tating blades above the plate, and is finally ca ried around to the opening y, through which drops onto the next plate fu, below.` Here it again similarly worked over by the arms ovl said shelf until it escapes through the shelf' ar drops to the next plate t, wh ere it is further work( until it drops through the opening onto the he;y ed plate to, where it is again similarly worki over by the arms until it drops through theope ing at one side of the heater upon the botto plate of Jghe mill. From this plate itis wiped swept off andforced into the molds c2 of the ma mold-cylinder by another set of arms or sweeps z. All of these rotating arms are beveled or inzlined, and tend collectively and in succession to Ulead the material, like spatulas', or as dough is ineaded, Working it over and over and convertng it into a doughy and cohesive mass of pulp. Phe bottom of the mill becomes filled or charged with this pulp, and the heater w is so constructed tud arranged within the mill that it is entirely iurrounded by peat, which thereby becomes con- ;iderably heated and is in more workable or plasyic condition-to be pressed into the molds.

".,Io lubricate and Warm the material While unler'the action'of the spatula-blades or sweeps, md passing under the mill, steam-pipes a2 may un through the mill, these pipes ,having suitle connections with a source of hot-steam suply, and being preferably provided with holes hrou gh which the steam under pressure is forced u jets and ejected into the mass of peat, the steam o appliedkeeping the mass sufficiently moist or `in temper77 to enable it to be readily worked by he rotary sweeps and formed into a strong plasic pulp or paste, which is heated by contact with nd proximity to the heater w before it passes in- 3 the molds, this heater being a hollow chest yith steam-passages into and from it.

The mold or blocleforming cylinder b2 is a large Yheel having' a series of peripheral molds, c2, ach provided with a suitable compressing and iecting-plunger, d?. At one side of the mold- 'heel or cylinder b2 is an endless apron or band, running over two drums, g2, and in contact ith the peripheries of the mold-cylinder, the and being driven by the mold-cylinder. As, L the rotation of the mold-cylinder, an open or npty mold comes tothe top, or directly under le center ofthe pulpingmill, the blades or sweeps press the peat into it, and, as the filled mold isses on, it soon comes against the apron f2. his apron is porous, and may be made of cants or other porous material, and the plungers may also be made porous; and as each. mold tates in contact with the band its plunger is rced out radially by a suitable cam mechanism, ereby compressing the peat in the mold against eband and expressing the water, which runs t' through the belt or apron and' also through e plunger. By this operation the peat is formed to solid and partially-dried blocks ready for the ral drying operation. After each mold has passed e apron f2 its plunger is forced still further out'- trd and ejects the block of peat, which falls upan endless apron, h2, running around drum the shafts of which turnin bearings on the der side ,of a long frame, k2. rlhis apron is pro- :led with va series of lugs or cross-strips, Z2, and

one end of the frame k2 is placed pile of ards or block-receivers, m2, piled between guide ces n2 and resting upon the apron, the receivbeing taken successively, one by one, by the gs or strips Z2, and as each moves under the ld-cylinder it receives the blocks' ejected or )pping therefrom, there being at all times a :eiver under the cylinder ready to take the wks. The apron may be made of any desiralocation for removal to a dry-house orto be piled in the open air.

During the passage of thepeat through the pulping or kneading mill I sometimes throw into or upon the mass oil or other inflammable liquid or powder; and to accomplish this in the best manner I prefer to use steam atomizingftubes, as follows: o2 is a steam-pipe having within it another pipe, pZ-the lower or open end of which is Within the outer pipe oz-through which is conveyed any'liquid or powdered substance which it maybe desirable to incorporate with the mass of peat in the process of manufacture. Thema'- terials so to be introduced, which may be oil, limewater, melted or pulverized gums', or pulverized ores, etc., are held in any convenient receptacle, and from thence are allowed Y may be forced through the inner pipe p2 in regulated quantity, steam Iat the same time being let on to pass through the outer pipeoz. As the liq-A uid or other matter passes from the end of the inner pipe it is at once caught by the steam within the outer pipe o2, atomizedand mingled With it, and forced, in the form of spray, into and through the mass of peat or other material with which the mill is filled, and which is kept in constant mo- -tion by the sweeps .operating within the mill, so that by this means any quantity, small or large, can be very thoroughly and evenly disseminated through the mass, materially adding to the value of the peat as an article of fuel.

'lhe mechanism of my apparatus may be driven by an arrangement of shafts, drums, gears, pulleys, and belts, as seen in the drawing, or in any other suitable manner.

After treatment in the pulpingmill it is sometimes found that the peat and the Water still remaining in it are so intimately mingled, 0r that the *peat has such an aflinity for the Water contain ed in it, as to render it extremely dilcult to express from it any material portion of the Water. In yorder to overcome this diiiiculty I mix with the peat straw, grass, rushes, husks, shavings of wood, or any similar substance-preferably in dry condition-the eect of which is to attract to these surfaces a portion of the moisture and under pressureY to Vdeliver it from the mass. VThe straw, grass, shavings, y pose of strengthening the fuel or adding to it cohesiveness, and, being combustible, such material forms practicallya component part of the fuel for heating purposes. The grass, straw, rushes, shavings, or other similar material used, may be previously saturated With oily or resinous mas terial.

In stead ofthe perforated plate a pervious apron may be arranged to operate in connection with the cylinder; ror the apron may be so arranged as to operate in connection with both cylinders.

I claim- 1. The process of treatment described, said process consisting in first compressing crude peat to extract a portion of the Water contained in or held by it, next dividing up the compressed peat and working or kneadingthe mass, either with or without the application of heat steam, or water, and

l length to conduct the blocksto ahy desired then compressing the peat, so worked, in suitato run through or &c., serve also the purble molds to extract more or less of its moisture and form it into suitable blocks for fuel.

2. Also, the process of treating peat in a pulping-mill by injection into or upon it of infiammable material.

3. Also, in combination with the pulping-mill, the cylinder fi for receiving.; and compressing the peat and delivering it in uniform quantities and at uniform intervals into the mill.

4:. Also, the rotary cutter p, in combination With the mold-cylinder 5. Also, the combination of a compressing and molding cylinder above a pulping-mill-a mill provided with rota-ry beaters or bladesand a block-forming mold-cylinder below the mill, all arranged to operate substantiallyr as described.

6. Also, the steam-pipe o2 and inclosed pipe p2, arranged to eject an inilammable liquid or powder and steam upon the mass of peat in the 7. Also, in combination with the block-forming and compressing-cylinder, the apron fZ for closing the molds and acting as a bed against which to compress the peat, and through which to express Water therefrom, the apron traveling with or being moved by the cylinder.

8. Also, in combination with the block-forming mold-cylinder, the endless carrier-apron'hz, pro-` L. H. LATIMER. (61)

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