US2876698A - Dryers - Google Patents

Description

DRYERS March 10, 1959 Filed Feb. 21, 1 955 3 Sheets-Sheet 2 INVENTOR. LEsL/E J. \S/SLEY acaw HTTOkZ/VEYJ March 10, 19 59 SISLEY 2,876,698

DRYERS Filed Feb. 21, 1955 5 Sheets-Sheet a lln - IIYVEN TOR. [ESL/E J J/SLEY JZMQW' DRYERS Leslie J. Sisley, Seattle, Wash. Application February 21, 1955, Serial No. 489,505 6 Claims. (Cl. 100-147) This invention relates to dryers and has reference more particularly to a means for the quick and effective drymg of such materials as the reduced bark of trees, sawdust or other ground or reduced cellulosic materials including bogged fuel.

It is the principal object of the invention to provide a mechanism of a relatively inexpensive and simple form of construction whereby wet or damp bark, sawdust, wood chips, and the like, can be quickly reduced to dry condition or to a low percentage of moisture content that will make its burning as fuel practical and economical.

It is also an object of the invention to provide a dryer especially for the drying of materials of the character above named, and especially for the drying of sawmill waste, including the bark which is removed from logs hydraulically and which bark usually contains such a high percentage of water that its value as fuel is very materially reduced.

Another object of the invention is to provide a dryer of the above character wherein feed screws are arranged to receive the material which is to be dried, after it has been ground or otherwise reduced to small pieces or particles, and which screws operate to effect the squeezing out all free water and then, by subjecting the material to further compression and friction cause it to be heated to such degree that remaining moisture is dissipated as steam and the material dried out.

A further object of the invention resides in the details of construction of parts, in their relationship or combination, and in the mode of operation of the machine as will hereinafter be fully described.

In accomplishing these and other objects of the invention, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein:

Fig. 1 is a side elevation of a dryer embodied by the present invention; a part of the dryer chamber being shown in vertical cross section.

Fig. 2 is a plan or top view of the same.

Fig. 3 is a horizontal cross section of the dryer on line 3-3 in Fig. 1.

Fig. 4 is a horizontal section on line 4--4 in Fig. 2.

Fig. 5 is a sectional detail showing a press plate mounting.

Fig. 6 is a sectional detail of a part of a screw and screw housing.

bogged material. terial is caused to flow into a feed hopper and from this is fed into the machine wherein devices coact to subject it to pressure and frictional heat to first extract the moisture and then effect the drying operation.

In its present preferred form of construction the drying chamber of the machine is vertically arranged,'that is, the enclosing housing and the succession of screws by which the material is advanced are mounted coaxially of a vertical driveshaft,. and the material is" received at the upper end of the housing and is dis-.

charged at its lower end.

As seen in Fig. 1, the machine is shown to comprise a main frame structure including a horizontal base or,

bed plate 10, one end portion of which is designed for the mounting of the machines driving motor thereon; this being the right hand end of the base as shown in Fig. 1; the motor therein being designated in its entirety by reference numeral 11.

The left hand portion of the bed or base frame, in reference to its showing in Fig. 1, is square in plan, and mounted therein, at its four corners, are vertical shafts,-

each designated by reference numeral 12. All shafts are of the same length and at their upper ends extend through and are rigidly joined by a rectangular top plate 15. It also is shown in Fig. 1 that the four shafts have their lower and upper end portions slightly diametrically reduced for mounting in the bed plate 10 and top plate- 15, respectively, and nuts 16 are applied to the shaft ends and tightened against the plates to secure them in place."-

. through the mediacy of anti-friction bearings 21 and 22.

The present dryer is designed primarily as a means that it resembles or is in the form of what is known as It is noted best in Fig. 1 that the upper bearings 21, as applied in plate housing 17, are of the roller thrust type and are confined between a nut 24 that is threaded onto the shaft and the base wall 17x of the bearing housing. The extreme lower end of the shaft 20 is mounted in the ball bearing 22 and this is set in a seat provided therefor in the bearing housing 18. 7

At its upper end, the drive shaft 20 is rotatably mounted through the mediacy of ball bearings 25 that are set in a downwardly opening socket 27 formed centrally in the upper end plate of the machine. The shaft 20 as thus supported, mounts thereon and'drives the succession of feed screws whereby the'material to be dried is advanced through the machine; these screws presently being described in detail. For the driving of the driveshaft 20, it is equipped at its lower end, between the plates 10a and 10b of the base 10, with a driving sprocket wheel 30; this being keyed to the shaft as indicated at 31. The driving motor presently being used is a three phase, sixty cycle electric motor of sixty horsepower, and operates at 900 R. P. M. It is mounted on the bed plate 10 with its driveshaft 11x extended vertically downward and equipped at its lower end with a relatively small sprocket wheel 32, disposed in the horizontal plane of the sprocket wheel 30. A chain belt 33 operates about the two sprocket wheels to drive the shaft 20. p a Keyed to shaft 20, in a continuing relationship there: along, are the feed screws which are designed for. the advancement of a selected material through the machine for drying. As herein illustrated there are four of these screws which will hereinafter be referred to as screw sections, and they are designated respectively, by nnmerals '35, 35a,'3:5b and 35c; the larger one being atthe Patented Mar. 10, 1959 In this reduced condition, the ma- 'l upperendof the. series. In a machine presently in use, the upper screw is 18 inches in diameter, and the others are successively decreased in diameter about one-half inch;

Each screw section is of uniform diameter throughout its; length and is fitted for rotation within a cylindrical enclosing housing, which housings are designated respectively by reference numerals 36, 36a, 36b, and 360 from the larger to the smaller one. Each housing has its upper end portion outwardly flared, as as 36x to form a sort'of conical receiving hopper into which the material being dried, as discharged from the next higher screw section, will be received. At its lower end each housing has. an out-turned flange 361 by means of which it is mounted on an individual supporting frame. These several frames are mounted by the frame structure as comprised by the base and top plates 11 and the four vertical shafts 12; the four frames by which the screw enclosinghousings are mounted are designated respectively by reference numerals 40, 40a, 40b and 400 in succession from the upper end of the machine downwardly.

Each of the frames 49, 40a, 40b and 400 is of rectangular outline and is provided in its four corner portions with guide, bearing 41 through which the supporting shafts 12 slidably extend. Each horizontal frame is yieldingly supported at its corners on coiled springs 42 that are applied about the shafts with their lower ends resting on nuts 43 that are adjustably threaded on the shafts. The plates are eachv limited in their upward movement by engaging against nuts 44 that are threaded onto the shafts. The resistance of each frame to downward yielding movement can be made more or less by adjusting the nuts 43 toward orfrom the corresponding nuts 44.

Each plate or frame 40 is formed with a central opening45 which contains the lower end portionof the correspondingsection of the feed screw therein, and each of these openings has an inwardly and downwardly beveled conical surface, as at 45a providing a restricting mouth leading into a cylindrical passageway 45x as provided by the-four frames 40, 40a, 40b and 40c, are of stepped diameters decreasing in diameter from the upper end of the feed screw downwardly, and each passage having a diameter that is lesser than that of the screw section above it and equal to the outside diameter of the screw section immediately below it. Each screw section has a single thread and they operate, as the screws revolve, to advance material between the turns of the thread, downwardly within their respective enclosing housings.

Each housing 36, 36b, 360 has its cylindrical body portion perforated for easy escape of water and steam and these perforated portions are lined with sleeves made of line mesh screen which will pass steam and water therethrough but retain the material. In Figs. 5 and 6 plate perforations are designated by numeral 46 and the sleeves at 47.

The material to be dried is fed through openingsSO in the upper end frame into the hopper shaped upper end of the uppermost screw housing 36, and is there taken up by the threads of the rotating feed screw and is advanced downwardly through the opening of the corresponding plate and forced through the constructed passage 45x. The resistance to passage of the material through the opening places it under compression in the enclosing housing and this results in free water being squeezed out. This water as squeezed out passes through the lining sleeve 47 of small mesh screen and perforations 46 in the cylindrical wall to the outside of the latter and is drained from the machine.

The amount of pressure to which. the. material is subiected can be varied as desired or required by adjustment of the spring supporting nuts 43 on the shafts 12.

As the material progresses downwardly through the plate openings 45x from each screw sectionv to the next lower one, it is received between the screw section and its housing and additional water ,squeezedout. The pres- 4 sure finally causes substantially all free water to be extracted and the pressure and friction creates heat which changes remaining moisture to steam and effects further drying. As the de-watered and dried material is discharged from the lowermost end passage 45x onto the top of the bed plate 10 it is picked up by radial fins 63 formed on a rotating base member 65 that is mounted about the shaft 2t) immediately below the lower end section of the screw, and is centrifugally discharged by these fins through a discharge spout 66.

It is anticipated that machines of this character can be made in larger or smaller sizes; that they may include more or less screw sections of various lengths, and that the plate pressures can be adjusted as desired to effect a quicker or slower rate of water extraction and drying. The driving means can be other than here shown and arranged to meet any special requirement.

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

l. A machine for the drying of reduced, moisture containing cellulosic materials; said machine comprising a housing equipped for receiving said material thereinto at one end and for its discharge atthe other end, a driven screw shaft contained in said housing, a series of independent screw sections mounted on said shaft and adapted to cooperate with the housing for the progressive advancement of material through the housing, die plates mounted in the housing substantially in the planes of adjoining ends of said screw sections, said die plates having inwardly extended portions which substantially constrict the openings between the screw sections whereby the material extruded through the constricted openings is in relatively thin, ribbon form die plate mounting means yieldingly mounting the die plates for movement thereof away from the discharge end portions of the screw sections in accordance with and under the pressure of the advancing material, and means on said housing provided for the ready escape of moisture extracted from the material under the pressure of the screw sections.

2. A machine as recited in claim 1 wherein the screw sections are successively reduced in diameter'and each of the die plate openings is of lesser diameter than the screwsection by which the material is advanced thereto, and each die plate has an entrance portion that is flared to a diameter that is substantially equal to that of the feeding screw section.

3. A machine as recited in claim 1 wherein the machine has a frame structure in which said die plates are supported on coiled springs to yield in accordance with and under the feeding force of the screw sections.

4. A machine as in claim 3 wherein said housing sections are each spaced from the next preceding die plate to avoid interference under spring action.

5. The machine of claim 4 including means for varying the spring pressure.

6. A machine as recited in claim 3 having a main frame structure which supports said screw shaft for rotation therein, a plurality of guide shafts arranged about said screw shaft, and said die plates being mounted on the guide shafts for movement independently of each other and said springs are mounted by the guide shafts and bear against the die plates for their yielding support.

References Cited in the file of this patent UNITED STATES PATENTS- 714,174 Guy Nov. 25, 1902 1,769,658 Veenhuyzen July 1, 1930 2,135,325 Burt et al. Nov. 1, 1938 FOREIGN PATENTS- 27,234 France J an. 22', 1924 47,437 Germany June 21, 1889 556,945 France Apr. 24, 1923 1,069,735 France Feb. 17, 1954

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