Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
  • B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
  • B07B1/00—Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
  • B07B1/12—Apparatus having only parallel elements
  • B07B1/14—Roller screens
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
  • B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
  • B07B1/00—Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
  • B07B1/12—Apparatus having only parallel elements
  • B07B1/14—Roller screens
  • B07B1/15—Roller screens using corrugated, grooved or ribbed rollers

Definitions

• the present invention relates to a screen used in the fine screening of solid material, such as rock material and coal, provided with a plurality of successive, rotatable screening members suitably spaced in the proceeding direction of the material .
• the roller screen of the FI patent 56,131 is adjustable, i.e. the distance between the rollers is increased in the proceeding direction of the material in order to adjust the overflow, so that essentially all pellets forming the overflow are larger than those separated therefrom and returned to pelleting.
• the rotatable rollers of the FI patent 56,131 set the material to be screened only and essentially into horizontal motion, in which case the material either rolls or slides on top of the rollers.
• vertical motion which is advantageous for screening and normally obtained by means of a vibrator, is not created in the process.
• the object of the present invention is to eliminate some of the drawbacks of the prior art and to achieve an improved screen which is more secure in operation, and where an essentially vertical motional component also is obtained for the material to be screened by means of suitably shaping the screening members .
• the essential novel features of the invention are apparent from the appended patent claims .
• the screen is provided with a plurality of suitably spaced rotatable screening members arranged transversally with respect to the proceeding direction of the material.
• the screening members essentially deviate from circular shape, but in such a fashion that at least 50% of the cross-sectional circumference is curved.
• the screening members are essentially symmetrical in relation to their rotating axis.
• the screening members are coupled to each other, so that the distance between two successive screening members remains essentially the same at the different stages of screening.
• the screening members of the screen of the present invention are for example essentially elliptical in cross-section, so that the whole cross-sectional circumference of the screening member is curved.
• the cross-section of a screening member may also be a circle, which is removed of essentially equal-sized segments located symmetrically with respect to the rotating axis of the screening member, the number of these segments being advantageously two or three.
• at least 50% of the cross-sectional circumference is curved and is composed of circular curves .
• the screening members are arranged in an advantageous fashion with respect to each other, so that two successive screening members are turned at an angle of essentially 90° in relation to each other.
• every second member is essentially in horizontal position, and every second member essentially in vertical position.
• the particles are set to an essentially rising or lowering motion due to the effect of the screening members, so that both the horizontal and vertical motional components affect the material to be screened, and the single particles contained therein.
• the screening members of the screen of the invention are further installed so, that the screen aperture in between two successive screening members is equal-sized in all intervals throughout the screen. Moreover, two successive screening members are synchronized by means of a gearing member, so that the screen aperture remains essentially the same throughout the screening process, owing to the advantageous cross-sectional symmetry of the screening members .
• the screen of the present invention is meant for the fine screening of the material to be screened, in which case the screen aperture is advantageously of the order 4 - 25 mm.
• the screen aperture is advantageously of the order 4 - 25 mm.
• two or more screens with different screen apertures can be connected, so that they form a screen trac of several screens. These screens are advantageously operated either with one and the same or with several different actuator devices.
• figure 1 illustrates a preferred embodiment of the invention, seen in a partial side-view cross-section
• figure 2 illustrates the coupling of the screening members of the preferred embodiment of figure 1, seen from the top
• figure 3 illustrates another preferred embodiment of the invention, seen in a partial side-view cross-section
• figure 4 illustrates the coupling of the screening members of the preferred embodiment of figure 3, seen from the top
• FIG. 5 further illustrates an advantageous cross-section of the screening member of the invention.
• figure 6 further illustrates an advantageous cross-section of the screening member of the invention.
• the material conveyed on the conveyor belt 1 is fed onto the screen 2.
• the screen 2 is provided with screening members 3 arranged transversally to the proceeding direction of the material, spaced at a distance determined by the screen aperture 11.
• the screening members 3 are essentially elliptical in cross-section, and the screening members 3 are mutually installed so that every second member 3 is essentially in vertical position, and every second member 3 is essentially in horizontal position, i.e. in alternate members, the long axis of the ellipse is in turns in vertical or in horizontal position.
• the screening members 3 are interconnected, so that at the end of the screening member 3 (figure 2) there is installed a sprocket 5 by intermediation of a gearing 4.
• the sprockets 5 are further connected to each other by intermediation of roller chains 6.
• the rotation of the roller chains 6 is achieved by means of the actuator arrangement 7.
• a hopper 8 underneath the screen 2 through which hopper 8 the fine material that has penetrated the screen proceeds to an underflow conveyor belt 9 located below the hopper 8.
• a conveyor belt 10 at the end of the screen with respect to the proceeding direction of the material is provided.
• the screening members 21 are spaced according to an interval determined by the screen aperture 27.
• a sprocket 23 In order to operate the screening members 21, at the end of each member 21 there is installed a sprocket 23 by intermediation of a gearing 22.
• the sprockets 23 are interconnected by a roller chain 24.
• the roller chain 24 is further arranged to pass around a special return roller 25.
• the actuator arrangement 26 of the screen 20 is connected to the return roller 25 according to the drawing.
• the screen of figures 3 and 4 essentially corresponds to the preferred embodiment illustrated in figures 1 and 2.
• the screening member 31 is in cross-section composed of two opposite circular curves and two connecting, parallel linear parts. According to the invention, two adjacent screening members 31 are advantageously installed, with respect to each other, so that the parallel linear parts of the cross-sectional surface of the screening member 31 are alternatingly either essentially in vertical position or essentially in horizontal position.
• the cross-sectional shape of the screening member 32 of figure 6 is advantageously achieved so, that from a circular cross-sectional surface, there are removed, symmetrically with respect to the rotating axis of the screening member 32, three segments, in which case the cross-sectional surface is formed of both curved and linear parts, and the proportion of the curved parts is at least 50% of the whole cross-sectional circumference.
• the location of the actuator arrangement of the screen can vary in the different applications .
• the actuator arrangement can be operated either through specific gearing, or the actuator arrangement can be connected to some known sprocket, or each screening member may obtain its rotatory force from a power transmission axis running along the side of the screening members, which axis is connected to the screening member by means of sprocket gearing.
• the cross-section of the screening members may vary within the scope of the appended patent claims.

Applications Claiming Priority (3)

Publications (2)

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ID=8536110

Family Applications (1)

Country Status (8)

Families Citing this family (7)

Family Cites Families (4)

• 1992
  • 1992-10-26 FI FI924854A patent/FI93803C/fi not_active IP Right Cessation
  • 1992-11-10 ZA ZA928646A patent/ZA928646B/xx unknown
• 1993
  • 1993-10-25 AT AT93922970T patent/ATE184514T1/de not_active IP Right Cessation
  • 1993-10-25 DE DE69326476T patent/DE69326476T2/de not_active Expired - Lifetime
  • 1993-10-25 WO PCT/FI1993/000435 patent/WO1994009917A1/fr active IP Right Grant
  • 1993-10-25 EP EP93922970A patent/EP0665773B1/fr not_active Expired - Lifetime
  • 1993-10-25 AU AU51788/93A patent/AU683228B2/en not_active Ceased
  • 1993-10-26 CN CN93119493A patent/CN1086746A/zh active Pending

Non-Patent Citations (1)

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