Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B30—PRESSES
  • B30B—PRESSES IN GENERAL
  • B30B9/00—Presses specially adapted for particular purposes
  • B30B9/02—Presses specially adapted for particular purposes for squeezing-out liquid from liquid-containing material, e.g. juice from fruits, oil from oil-containing material
  • B30B9/12—Presses specially adapted for particular purposes for squeezing-out liquid from liquid-containing material, e.g. juice from fruits, oil from oil-containing material using pressing worms or screws co-operating with a permeable casing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B30—PRESSES
  • B30B—PRESSES IN GENERAL
  • B30B9/00—Presses specially adapted for particular purposes
  • B30B9/02—Presses specially adapted for particular purposes for squeezing-out liquid from liquid-containing material, e.g. juice from fruits, oil from oil-containing material
  • B30B9/12—Presses specially adapted for particular purposes for squeezing-out liquid from liquid-containing material, e.g. juice from fruits, oil from oil-containing material using pressing worms or screws co-operating with a permeable casing
  • B30B9/121—Screw constructions

Definitions

• the present invention relates to a screw press, which compresses and dewaters more or less moist cellulose-con ⁇ taining and/or fibrous materials in pieces, e.g. waste pa ⁇ per, wood, grass, straw and other harvest products, peat, bark, cellulose and the like, in order to produce bri ⁇ quettes
• which screw press comprises a feed unit having an input portion for the material, which is to be comp ⁇ ressed, at least a first press cone for a forceful comp ⁇ ressing of the material, an output opening for the co p- ressed and dewatered product, a rotary screw, which ex ⁇ tends from said feeding unit at least into said first press cone, as well as driving means to turn the screw.
• Screw presses are also known in a plura ⁇ lity of designs for dewatering fiber materials and other compressible materials in the form of pieces. Embodiments of such screw presses are shown in US-A-2 615 385 and in US-A-4 121 967. By means of these and other known screw presses materials having a very high moisture content can be dewatered but not to such an extent as is requried when producing fuel briquettes.
• the object of the present invention is to design a screw press of that kind, which is stated in the preamble and by means of which " it is possible to dewater and to produce briquettes from the above-mentioned materials having ois- ture contents of as high as 60%, when hard, quite continu ⁇ ous briquettes having very high dry contents are produced.
• the wall of the pressure cone is impermeable, at least in one zone of the same, where it is substantially axially extended, so that local, very high pressures can be built up.
• a jacket section preferably is ar- ranged between the feed portion and the fully jacketed pres ⁇ sure cone or pressure cone zone, which jacket section is provided with drainage openings.
• This water must not be locked up inside the central portion of the compressed bo ⁇ dy without a chance to be pressed out towards the drainage openings in the jacket and hence, the screw press is, acc ⁇ ording to a preferred embodiment, designed in such a man ⁇ ner that the compressed body in or adjacent to the area of the drainage openings is cracked, so that the water from the central portion of the compressed body can be evacuated through the cracks outwards towards the jacket and then through the drainage openings in it.
• Figure 1 is a longitudinal section of the screw press
• Figure 2 is a lateral view of the screw
• Figure 3 shows the screw in a view III-III in Figure 2
• Figure 4 is a longitudinal section of a dewatering cylin ⁇ der and an attached first pressure cone.
• the screw press shown in Figure 1 is mounted on a base 1.
• the screw is mounted on .base 1 by means of its feed por ⁇ tion 2, which is provided with an input portion 3.
• a feed hopper 4 is arranged above the input portion.
• a down-feeder 5 is disposed, which oscillates in i vertical direction and is driven via a crank 6 and transmission means 7 by driving shaft 8 of an electric motor 9.
• Driving shaft 8 is extended through a shaft housing 10 and is designed to drive a screw 11.
• Screw 11 extends through input portion 3, also through a dewatering cylinder 12 and finally into a first pressure cone 13.
• a second pressure cone, which constitutes a di ⁇ rect extension of first pressure cone 13, has a reference numeral 14 and a terminating nozzle having a third conical constriction 16 has reference numeral 15.
• Dewatering cylinder 12 and the preliminary portion of the connecting first pressure cone 13, Figure 4 are on their interior sides in a way known per se provided with longi ⁇ tudinal bars 17, which prevent the compressed material from rotating in the thread turn together with screw 11.
• the reference numeral of this zone is 18 - the jacket of dewatering cylinder 12 is provided with a plurality of drainage holes 19, which are distribu ⁇ ted around the jacket. They have a diameter of 3 mm.
• Drai- nage zone 18 is surrounded by a casing 20, which collects water, which flows or is forced out through holes 20.
• First pressure cone 13 is in its central portion surrounded by a cooling jacket 22, through which cooling water flows.
• the thread or wings 28 of screw 11 are not extended into second pressure cone 14, which by means of threads 23 is tightened to first pressure cone 13, but in return an ex ⁇ tension of core 27 of the screw is extended with an ex- tension piece 45 into said second pressure cone 14.
• This second pressure cone 14 is surrounded by a cooling jacket 24, through which cooling water flows in order to carry off heat, which is generated also in this second pressure cone.
• the terminating nozzle 16, the terminating inner di- ameter 25 of which is chosen in accordance with the desi ⁇ red diameter of the briquettes, is also mounted on the pre ⁇ ceding pressure cone by means of screwing.
• Core 27 of screw 11 has a decreasing diameter along its length and partly also a varying shape.
• Thread 28 has a varying pitch along the length of the screw.
• thread 28 has a cylindric exterior contour, which in the area of first pressure cone 13 is transformed into a conical shape.
• Screw 11 can as far as the varying pitch of thread 28 is concerned be divided into a plura ⁇ lity of zones I-VI. Zone I - a large pitch - one thread turn 28A
• Zone II a moderate pitch - three thread turns 28B
• Zone III a very large pitch - one thread turn 28C
• Zone IV a moderate pitch - three thread turns 28D
• Zone V a small waved pitch - three thread turns 28E
• first thread turn 28A zone I
• zone II the thread pitch is somewhat smaller and during these three thread turns 28B a certain compressing of the material takes place.
• zone III in dewatering cylinder 12
• the very large thread pitch leads to a tearing apart of the comp- ressed material anew, which results in a multitude of cracks in the material with a predominantly radial direc ⁇ tion.
• the material is compacted again in the following three thread turns 28D in zone IV in dewatering cylinder 12.
• screw 11 has a conical shape.
• the terminating thread turn in zone IV extends into pressure cone 13 with a moderate pitch.
• the following three thread turns 28E have a very small waved pitch. This feature as well as the conically decreasing shape of the thread turn lead to a very force- ful additional compressing of the compressed material, while a very high pressure and heat is generated.
• the waved or winding shape of the thread results in a compressing of the compressed material by jerks, which has proved to be particularily effective, when trying to achieve a maximal compressing, and at the same time seems to facilitate the water removal. The latter effect seems to occur in the clearance or unloading phases, which follow every crest of a wave on the thread.
• Core 27 of the screw is shaped in the thread path between the thread turns in such a way, that the thread path bot- torn in axial sections is bowl-shaped, which is known per se.
• the mean diameter of screw core 27 is in the first three zones I-III and also in about half the fourth zone IV unalterably the same.
• the shape of screw core 27 in the remaining part is quite complicated.
• the diameter of thread path X is smaller than in the preceding thread turn.
• the diameter decreases further but to different degrees on different sides of the rota ⁇ tion axis, as is shown in Figures 2 and 3.
• radius R is less than R.
• radius R is smaller than the largest radius R 5 in thread path bottom 42.
• thread 28 as well as core 27 are designed in such a manner, that the compressed material is subjected to forceful local pressure increases, followed by pressure drops in pressure cone 13, which is imperme ⁇ able.
• This certainly implies that the compressed material is throughly kneaded in pressure cone 13, so that voids are formed, in which water and vapor can be accumulated under a high pressure and at a high temperature. These voids are forced backwards. Why this happens is difficult to explain and it can only be observed as a fact.
• the terminating pin 45 is eccentrically disposed but is parallell with the screw axis, which means that its point 46 while it is rotating describes a small circle, which prevents the packing of the canal, which screw core 27 has formed in the middle of the compressed body.
• the fi ⁇ nished briquette material, which is pressed out through the terminating nozzle 15, is tube-shaped, so that steam also can leave pressure cone 13 in this central channel, in which a passage is kept open all the time by means of eccentric rotary pin 45.
• Driving means used to turn the nozzle has symbolically been indicated with nume ⁇ ral 51.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Processing Of Solid Wastes (AREA)
• Materials For Medical Uses (AREA)
• Press Drives And Press Lines (AREA)
• Iron Core Of Rotating Electric Machines (AREA)
• Paper (AREA)
• Dry Formation Of Fiberboard And The Like (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

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Family Applications (1)

Country Status (9)

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Family Cites Families (2)

• 1986
  • 1986-03-12 SE SE8601152A patent/SE452331B/sv not_active IP Right Cessation
• 1987
  • 1987-02-16 DE DE8787901711T patent/DE3773927D1/de not_active Expired - Fee Related
  • 1987-02-16 AU AU71281/87A patent/AU7128187A/en not_active Abandoned
  • 1987-02-16 AT AT87901711T patent/ATE68515T1/de not_active IP Right Cessation
  • 1987-02-16 EP EP87901711A patent/EP0301000B1/de not_active Expired
  • 1987-02-16 WO PCT/SE1987/000075 patent/WO1987005619A1/en active IP Right Grant
  • 1987-11-03 NO NO874588A patent/NO168430C/no unknown
  • 1987-11-12 DK DK592187A patent/DK167934B1/da not_active IP Right Cessation
• 1988
  • 1988-09-12 FI FI884188A patent/FI92478C/fi not_active IP Right Cessation

Non-Patent Citations (1)

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