Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
  • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
  • B02C4/00—Crushing or disintegrating by roller mills
  • B02C4/28—Details
  • B02C4/32—Adjusting, applying pressure to, or controlling the distance between, milling members
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
  • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
  • B02C4/00—Crushing or disintegrating by roller mills
  • B02C4/28—Details
  • B02C4/32—Adjusting, applying pressure to, or controlling the distance between, milling members
  • B02C4/38—Adjusting, applying pressure to, or controlling the distance between, milling members in grain mills

Definitions

• the invention relates to a roller mill with two grinding rollers which can be adjusted relative to one another to form a roller gap and which are coupled to one another in terms of drive in such a way that they rotate at different peripheral speeds.
• Roller mills are used in grinding plants to grind grain and comparable products.
• suitable coupling gears which are mostly formed today by toothed belts, the two grinding rollers are coupled to one another in such a way that their mostly corrugated circumferential surfaces move in the same direction at the nip, so that the product is transported through the nip.
• compressive forces act on the cereal grains, but also shear and friction forces due to the different circumferential speeds of the rollers, so that the product is not only crushed but also ground.
• the grinding rollers should be set apart so that they do not rub against each other and therefore wear out prematurely.
• an engagement and disengagement mechanism is provided for turning the rollers on and off, with which one of the two rollers is moved radially with respect to the other roller by hand or with the aid of a pneumatic or hydraulic drive. It is also known to couple the engaging and disengaging mechanism with a drive for a feed roller, via which the product is fed into the nip. This ensures that the rollers are automatically disengaged when the feed roller is switched off and therefore no product is fed. However, if the product supply is already interrupted upstream of the feed roller, the rollers must be disengaged by hand, unless a suitable sensor is available to detect the lack of product.
• the object of the invention is to provide a roller mill with a simplified engagement and disengagement mechanism.
• At least one of the grinding rollers is movable in a direction tangential to the roller gap. stored and is elastically biased in this direction in a position in which the nip is enlarged to a predetermined size.
• the predetermined Maj3 of the nip in the disengaged position is chosen depending on the product to be ground so that the width of the nip is still slightly smaller than the average diameter of the product particles.
• waltz chair Since the waltz chair is also self-releasing in the event of a product shortage, a high level of functional reliability is achieved. Another advantage is that no pneumatic or hydraulic drive source is required for the automatic engagement and disengagement of the rollers. This also avoids the risk that the ground food will be contaminated by a leak in the hydraulic system.
• the movably mounted roller is preferably that which has the lower peripheral speed, and is biased against the transport direction and is indented by the product in the transport direction.
• the engaged position of the movably mounted roller is preferably limited by a stop which has a predetermined breaking point. If If foreign bodies get jammed in the roller gap, the predetermined breaking point breaks, so that the movably mounted roller can swing through in the direction of transport and thus major damage can be avoided.
• the coupling mechanism for the two grinding rollers is preferably formed by a crossed, ie 8-shaped belt drive, which has the necessary flexibility for the engagement and disengagement of the rollers.
• This design of the coupling gear also has the advantage that the mechanical stress on the bearings of the grinding rollers is reduced in the grinding operation, since the belt drive counteracts the moving apart of the two rollers.
• the arrangement can be chosen so that a certain self-regulation of the roller pressure is achieved.
• Circular belt drives are particularly preferred, the belts of which loop around the associated pulleys several times and mesh with one another at the intersection points. This makes it possible to transmit high torques and to minimize the skewing of the drive belts.
• Coupling gears are preferably provided on both axial ends of the two grinding rollers. In this way, a uniform roller pressure can be achieved over the length of the nip.
• the grinding roller has a cylindrical roller body which is detachable on both ends by centering disks is completed, each carry a stub axle. If the grinding rollers have to be re-grooved or re-sharpened, this design enables the two centering disks to be pulled apart axially so that the cylindrical roller body can be removed without having to dismantle the bearings and the coupling drives. This considerably reduces the work and time required to change the roll.
• the invention also relates to a roller mill with two grinding rollers which can be adjusted relative to one another to form a roller gap and which drive are coupled so that they with different
• At least one of the grinding rollers has a cylindrical roller body which is closed at both ends by releasable centering disks, each bearing an axle stub.
• the invention also relates to a roller mill with two grinding rollers which can be adjusted relative to one another to form a roller gap and which are coupled to one another by a coupling gear in such a way that they rotate at different circumferential speeds, in which the coupling gear is a crossed circular belt drive, the round belt of which loops around associated pulleys several times, that the intersecting strands of the round belt intermesh in a comb-like manner.
• the coupling gear is a crossed circular belt drive
• FIG. 1 shows a schematic end view of a roller mill according to the invention in the disengaged position
• Figure 2 shows the roller mill of Figure 1 in the engaged position.
• FIG. 3 shows the roller mill according to FIG. 2 in a simplified top view
• Fig. 4 is a schematic end view of a coupling gear
• FIG. 6 shows an axial partial section through a grinding roller in the operational state
• FIG. 7 shows a partial section through the grinding roller in the expandable state.
• FIG. 1 shows a roller mill with two grinding rollers, hereinafter referred to as rollers 10, 12, which together form a roller gap 14. The associated machine frame and drive devices and the like have been omitted in FIG. 1 for reasons of clarity.
• the roller 10 is mounted with stub axles 16 stationary in the machine frame and is driven clockwise.
• the roller 12, on the other hand, is mounted with its stub axles 18 in a rocker arm 20 which in turn can be pivoted about an axis 22 which is parallel to the roller gap 14 and is approximately at the same height therewith.
• the roller 12 is coupled to the roller 10 in such a way that it rotates counterclockwise at a slightly lower peripheral speed than the roller 10.
• the peripheral surfaces of the two grinding rollers therefore move at somewhat different speeds in the same direction, so that the product fed into the nip is transported downward through the nip 14.
• roller 12 Since the roller 12 is mounted in the rocker 20, it can move together with its stub axles 18 in an approximately vertical direction, that is to say in a direction parallel to an imaginary tangent which bears against the circumference of the roller 10 in the roller gap.
• Figure 1 shows the rollers 10, 12 in the disengaged position, in which the nip 14 has a predetermined width and the rollers do not touch each other.
• the rocker 20 is biased upwards against a stop 26 by a spring 24.
• the stop 26 is arranged so that the width of the nip 14 is slightly smaller than the average particle diameter of the product that is fed to the nip.
• the product 28 is now fed into the roller gap 14 from above, the individual product particles, for example grain kernels, are lightly squeezed in the roller gap.
• the roller 10 which rotates at a greater peripheral speed, tends to accelerate the product downwards.
• the product therefore exerts a downward frictional force on the circumference of the roller 12 which rotates at a lower circumferential speed. Since the rotation of the roller 12 cannot be accelerated, a downward force F arises which acts on the rocker arm 20 via the stub axle 18 and tends to move it downward around the To pivot axis 22. This pivoting movement of the rocker 20 out of the position shown in FIG.
• the rocker 20 rests against a stop 30 which is designed as a predetermined breaking point and normally prevents the rocker 20 from striking downward. Only in exceptional cases, such as when a foreign body jams in the nip 14, does the predetermined breaking point break, so that the stop 30 releases the rocker 20 and can spring it downward by enlarging the nip.
• An additional safety measure can optionally be that the axle stub 16 of the roller 10 and / or the axis 22 of the rocker 20 are resiliently mounted in horizontally movable bearing blocks, which are held in their operating position by strong springs.
• FIG. 3 the roller mill is shown in simplified top view.
• a machine frame can be seen with side parts 32, 34 and bearing housings 36, in which the roller 10 with its stub axles 16 is mounted.
• the roller 10 is driven by a motor 38 and a belt drive 40.
• In the side parts 32, 34 there is also an eccentric shaft 42 on which the axis 22 of the rocker 20 is arranged eccentrically.
• the eccentric shaft 42 can be rotated with an adjusting lever 44, so that the working width of the nip 14 can be precisely adjusted by appropriately displacing the axis 22. can be put.
• the stub axles 18 of the roller 12 extend freely through openings 46 in the side parts 32, 34 and are mounted in the rocker arm 20 with bearing housings 48.
• the stub axles 16, 18 of the rollers 10 and 12 are coupled to one another on both sides by coupling gears 50.
• These coupling gears 50 are designed as round belt drives and each have a round belt 52 which wraps the associated pulleys 54, 56 multiple 8-shaped and through the dead weight of a dancer 58 is kept under tension 10.
• the intersecting runs of the round belt 52 intermesh in a comb-like manner between the belt pulleys 54, 56.
• the coupling gears 50 are able to follow the pivoting movements of the rocker 20 when the roller 12 15 is engaged and disengaged.
• the round belts 52 preferably have a certain intrinsic elasticity, so that the slight changes in distance between the pulleys 54 and 56 can be buffered until a compensation has taken place via the dancer 58.
• the surface of the round belt 52 preferably has a relatively high coefficient of friction, so that in combination with the
• one of the coupling gear 50 is ones shown, in an end view '25 represents.
• idle mode that is, in the position shown in Figure 1
• the power flow goes from the pulley 56 directly driven by the motor 38 to the pulley 54, so that the trumms, designated 60 in Figure 4, are the pulling trims.
• These exert a small downward force component on the rocker 20, which, however, does not overcome the force of the spring 24 30.
• the roller 12 is driven directly by the roller 10 via the product in the roller gap 14, so that the coupling gear 50 acts as a brake.
• the trumms 62 are the pulling 35 trumms.
• the rocker 20 moves from the position shown in FIG. 1 to the position according to FIG. 2 when product arrives, the pulley 54 moves downward, so that the tensile stress in the runs 62 increases.
• These trumps 62 are therefore immediately able to apply a braking effect to the roller 12 if the product tends to accelerate this roller. This contributes to a rapid build-up of the force F, which pivots the rocker 20 further down.
• the trumms 62 also have the tendency to pivot the rocker 20 upwards again.
• the torque exerted on the rocker arm 20 by the trumps 62 is less than the torque which results from the force F at the roller gap, because the force application point of the trumms 62 on the pulley 54 is closer to the axis 22 of the rocker arm than the roller gap, so that the force F acts over a larger lever arm.
• the coupling gears 50 are provided on both ends of the rollers 10, 12, the forces transmitted through the coupling gears to the opposite ends of the roller 12 and the rocker 20 are essentially the same, so that a uniform rolling pressure over the entire length of the nip 14 is achieved.
• the pulley 54 which is assigned to the roller 12 and has the larger diameter, has grooves 64 with an approximately semi-cylindrical Profile on which is adapted to the cross section of the round belt 52 and this gives good guidance.
• the pulley 56 on the other hand, has grooves 66 which are approximately offset from the grooves 64 and have a greater width than this.
• the bottom of the grooves 66 is also tapered outwards (away from the roller 10).
• the trumms 60 can therefore run in with a relatively slight skew on the inside of the respective groove 66 (top in FIG.
• the trumms 62 which are the pulling trumms in the grinding operation, ensure that the round belt rotates around the pulley 56 as it rotates shifted outwards (downwards in FIG. 5) on the conical bottom of the groove 66 and then runs out on the outside of the groove 66 and runs into the groove 64 of the pulley 54 without a major change in direction. In this way it is achieved that the round belt 52 has only a slight skew when the belt pulleys 54, 56 are wrapped several times and is only subjected to little mechanical stress.
• the grinding rollers 10, 12 have, as usual, on their grinding surface, i.e. , their outer circumferential surface, a longitudinal, mostly slightly wired corrugation by which the grinding effect is improved. These grinding surfaces must be reworked and re-sharpened from time to time, for which it is necessary to remove the grinding rollers from the roller mill.
• a structure of the grinding rollers is now described with reference to FIGS. 6 and 7, which enables a particularly simple and time-saving removal of the rollers.
• the roller 10 is shown as an example for both grinding rollers.
• a cylindrical roller body 68 the outer circumferential surface of which forms the grinding surface 70, has a flat end surface 72 on both ends and an inner cone 74 on the inner circumferential edge.
• the roller body 68 is attached to the ends closed by a centering disk 76.
• the centering disk 76 lies with its outer circumferential area on a flat annular surface 78 on the end face 72 of the roller body and has two annular, concentric undercuts 80, 82 within this annular surface. These undercuts delimit an annular, to a certain extent inherently elastic web 84 which forms an outer cone 86 which is complementary to the inner cone 74.
• the stub shaft 16 is tubular and welded firmly to the centering disk 76.
• the stub axle 16 carries the pulley 56, which is only shown schematically here, and a roller bearing 88, which is received in the bearing housing 36 in an axially displaceable manner.
• the roller body 68 receives a clamping piece 90, which is held coaxially in the roller body by spokes 92 and has a threaded bore 94 at both ends.
• a threaded bolt 96 is inserted from the open end, which is screwed into the threaded bore 94 of the clamping piece 90.
• the two centering disks 76 are firmly clamped to the roller body 68.
• the stub axle 16 and the roller body 68 are axially clamped together via the clamping piece 90, the bending stiffness of the stub axle is increased for a given cross section.
• roller body 68 If the roller body 68 is now to be replaced, the two threaded bolts 96 need only be loosened in a few steps and unscrewed from the threaded bores 94.
• the stub axles 16 with their respective centering disks 76 can then be axially pulled off the roller body 68, so that the webs 84 come free from the inner cone 74, as shown in FIG.
• the roller bearings 88 which are axially fixed on the stub shaft 16, can move axially in the bearing housings 36.
• the roller body 68 In the state shown in FIG. 7, the roller body 68 can now be removed in the radial direction from the space between the centering disks 76 and replaced by a freshly refurbished roller body. The latter can then be just as easily reassembled by reversing the processes described above and braced using the threaded bolts 96, whereby it is precisely aligned and centered.

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• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Crushing And Grinding (AREA)
• Motorcycle And Bicycle Frame (AREA)

Applications Claiming Priority (4)

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• 2005
  • 2005-04-18 AT AT05740244T patent/ATE410231T1/de not_active IP Right Cessation
  • 2005-04-18 WO PCT/EP2005/004112 patent/WO2005102531A1/fr not_active Application Discontinuation
  • 2005-04-18 EP EP05740244A patent/EP1740309B1/fr not_active Not-in-force
  • 2005-04-18 DE DE502005005621T patent/DE502005005621D1/de not_active Expired - Fee Related

Non-Patent Citations (1)

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