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
  • B02C4/02—Crushing or disintegrating by roller mills with two or more rollers

Definitions

• the invention deals with a middle pressure more roll press for milling of granular materials, especially materials with grindability and different size of grain, where the press is composed from a driven roll and at least two milling rolls, the axes of which are parallel with the axe of driving roll.
• the cement clinker, lime, limestone, ores and pigments in these days usually tube - ball mills are usually used or vertical disk refiners, which are combined with the in the same time provided drying of milled raw material.
• the disadvantage of ball - tube mills is especially the not symmetrical process of milling, which is caused by undefined contact of the milling filling with the armoring of the grinding mill and with the grist eventually with other bodies, which increase the number of milling contacts. With it the bad energetic effectiveness of the milling is connected.
• the grist has to be supplied under the milling refining discs repeatedly.
• the corresponding equipment is further of large dimensions, heavy and over saturated with considerable amount of from great part unnecessarily re-circulated material.
• the duration of the milling is further prolonged by the necessary pneumatic or mechanic removal of grist, eventually by the combination of both these methods and in the same time the energetic consumption is increased.
• the object of this invention is a middle pressure more roll press for milling, grinding of grainy materials, especially materials with different grindability and different grain size, where the press is composed from a driving roll and at least two milling rolls, the axes of which are parallel to the driven roll axe.
• the essence of the invention is that the milling rolls are not provided with own drive, and their diameter is less or equal up to the half of driven roll diameter and they are set mechanically such a way, that between the surface of each of them and the to them opposite milling roll surface idle slots are formed such a way, that each idle slot is in direction of the rotation movement of the driven roll less as to it precedent idle slot and that each from the milling rolls is provided with means for their pressing in direction to the longitudinal axe of driving roll.
• ⁇ 0° to 15°
• ⁇ 35° to 55°
• ⁇ 75° to 90°.
• an advantageous construction version according to invention is the system of at least two milling rolls set on a common body, which is accommodated for angle slight turning around the driven roll longitudinal axe.
• the essence of the invention is also that the pressure force of milling roll, which is consecutive in of driven roll rotation speed direction, is greater as the pressure force of previous milling roll.
• the pressure forces are chosen so, that the pressure force of first milling roll is 15% to 25% and the pressure force of second roll is 250 to 50% of the total of pressure forces, acting to all milling forces. Additionally at least one pressure force can be periodically changeable.
• a middle pressure more roll press enables as to its compactness in regard to the up to now known construction versions a systematic milling of material and at the same time increases the energetic effectiveness of the milling process, and this namely such a way that the grist is formed before the transfer in three consecutive continuous steps, that means without transferring between the individual steps, the height of milled layer is systematically decreased and the influence of milling forces are more times repeated.
• stepwise increasing of loading forces with the following releasing is additionally increased the number of active contacts between the grains of milled material, what have a positive result in the process of partial cutting, whereas the not desired compressed pieces - which should be at recent constructions disconnected - are not created.
• FIG. 1 Possible variants of constructions of middle pressure more roll press according to the invention are schematically illustrated on enclosed drawings, where on the Fig. 1 the vertical cross section of middle pressure more roll press with three independent milling rolls is demonstrated, on the Fig. 2 the vertical cross section of an other construction version of middle pressure more roll press from the Fig. 1 is demonstrated, and on the Fig. 3 a construction version of middle pressure more roll press according to the Fig. 1 with three connected milling rolls is demonstrated and on the Fig. 4 a vertical cross section of middle pressure more roll press according to the invention and with milling roll connected with an independent self-locking hydraulic circuit is demonstrated.
• FIG. 1 An example basic embodiment of the construction of middle pressure more roll press according to the invention is schematically demonstrated on the Fig. 1.
• the press is composed from a driven roll 4 of diameter ⁇ with a longitudinal axe 40 , which is laying in the vertical plane 400 .
• the driven roll 4 is set on the co-axial spindle 41 and by mean of this it is coupled with the non demonstrated mechanism for its forced drive for rotation in the direction of the arrow R .
• three non driven rolls are set in the right upper quadrant in co-axial location with the driven roll 4 , where these rolls are free rotating and serving for milling and have in principle the same diameter d , e.g. the first milling roll 1 with longitudinal axe 10 , the second milling roll 2 with longitudinal axe 20_and the third milling roll 3 with longitudinal axe 30 .
• the longitudinal axes 10 , 20 , _30 of milling rolls 1 ,_2 , _3 are defining together with the longitudinal axe 400 of driven roll 4 the three planes 100 , 200 , 300, which are declined from the vertical plane 400 in direction _R of rotation of driven roll 4 with the angles ⁇ , ⁇ and .
• each from the milling roll rolls 1 ,_2 , _3 are set and turning and together with this setting they are connected with the non demonstrated mechanism, which provides the necessary milling pressure Pj ,_P2 and _P3 .
• Such mechanism could be for instance a pressing hydraulic mechanism of usual design.
• the setting of milling rolls is further made such a way, that at their side location in direction of pressures P_ ⁇ ,_Pg and JP 3 , that means in location nearest to the driving roll _4 there are between its surface and between the surface of corresponding milling roll 1 ,_2 , _3 a constant idle slots 11 , 21 , 31 formed, and this such a way, that their size is decreasing stepwise in direction R of the driven roll rotation.
• An other part of middle pressure more roll press according to the invention is the storage 5 with the grist 50 and with the output slot 51 , provided with the output edge 510 .
• the storage 5 is at the described example embodiment set over the driven roll 4 , namely in the area of vertical plane 400 .
• An other construction element is, that the grist storage 5 is declined against the driven roll 4 rotation direction R .
• the principle of stepwise decreasing of idle slots 1_1 , 21 , 31 , described at the first example embodiment remains at this embodiment preserved.
• this example embodiment can be completed with a sorting system 7 with sorter 70 , for instance with air sorter and a returning transport element 700 which is ended in the storage 5.
• the example embodiment according to the Fig. 3 differs from the previous ones principally in it, that the three milling rolls 1 , 2 and 3 - which are mutually turned in relation to the vertical plane 400 with angles ⁇ , ⁇ and -are set together with aid of the body 6, which is set swinging in relation to the longitudinal axe 40 of driven axe 4.
• the body 6 does not hang together with the essence of the invention and it is provided from one hand with not demonstrated means for setting of milling rolls 1, 2, 3 , and from other hand with means for setting of angle position of the assembly in the angle + - ⁇ in comparison to the vertical plane 400.
• the function of here also not driven milling rolls, their pressure forces Pj ,_P_2 and JP3 realized with known, for instance hydraulic means, and also the setting of their - on the Fig. 3 not demonstrated - idle slots remains the same.
• the milling rolls 1 , 2 and 3 are generally free turning, in an alternative version, which is not demonstrated on the Figs, at least one from them can be braked, and this mechanically or hydraulically, electrically, etc.
• FIG. 4 is schematically demonstrated the example embodiment version for regulation of the pressure force of milling roll by mean of a self-locking hydraulic circuit 8 , which is generally created according to an older patent AO 244 268.
• this modification demonstrated and described in connection to the first milling roll 1 and to it acting pressure force £ 1 only.
• the middle pressure more roll press according to the invention will work according to the Fig. 1 as follows.
• the grist of middle grindability composed for instance from material of same kind, as cement clinker with middle value of 80 Hg (Hardgrove) and with grains with size range from 0.1 mm to 45 mm, acquired as output raw material from the not demonstrated rotary kiln, is stored in the storage 5 .
• the input layer of grist 50 is pulled in the first idle slot 11 , where the first milling phase - the forming - is realized by the mutual influence of both rolls and the pressure force Pj .
• the destruction of greater grains of grist 50 is then coming out from the area of first milling roll 1 in a layer with lesser grain size differences of milled material and the thickness of which corresponds at least to the size of first idle slot ⁇ .
• the pressure to the formed grist 50 will be released and the layer is taken away with the corresponding part of driven roll 4 surface and is transported to the second milling roll 2 , the idle slot of which is lesser as at the previous one - the first milling roll 1 , and so it is lesser as the thickness of layer from the previous milling stage.
• the second milling roll 2 which is turning once more in the direction of arrow S , is acting to the formed grist 50 by mutual influence of the surfaces of driven roll 4 and the second milling roll 2 , the lesser idle slot 21 and the greater pressure force P 2 such a way, that it will be pre milled and it will be better calibrated in height.
• the output layer of grist 50 with a lesser thickness passes after repeated releasing from the pressure force P ⁇ to the third milling roll 3 , where then under influence of the pressure force P 3 , which once more greater as in the previous stage, and under influence of once more lesser idle slot 3 , the final after milling of grist 50 , will be realized, and then it will without restraint fall out in direction of the arrow U to further technological processing.
• the middle pressure more roll press according to Fig. 2 is working generally similarly to the previous example embodiment.
• the grist is for instance cinder with a middle grindability of 35 Hg and with grain size from 0.1 mm to 5 mm.
• the grist 50 after passing between the individual milling phases is transported in direction R of the rotation of driven roll 4 for a longer period of time and for this reason it is released from the previous pressure phase longer as it had been at previous example.
• the undesirable rough fraction is then transported outside the sorting system 7 and with the returning transport mean 700 returned to the storage 5 , as it is on the Fig. 2 demonstrated with dashed line.
• the greater angle distance of milling rolls 1 , 2 ,_3 also enables to enter the finer fraction, separated in the sorting system 7 to an other as first milling step. It enables also to transport it to such step an independent component of the mixed grist 50 .
• middle pressure more roll press according to Fig. 3 is generally the same as at design according to Fig. 1.
• angle location of all three milling rolls 1 , 2 , 3 . n whole with a slight turning of the body 6 with an angle + ⁇ it is but possible to adjust namely the input conditions to he system of milling rolls 1 , 2 ,_3 to lesser continuous character changes of grist 50 .
• the solution of construction of middle pressure more roll press according to the invention is not limited to the here described example embodiments. So it is possible without change of the essence of invention to build a construction with greater number of milling rolls, eventually to accommodate the construction for independent setting of angle location of individual milling rolls 1 , 2 , 3 . It is possible also, especially at convenient input conditions of the grist 50 given under the milling rolls 1 , 2 , 3 , for instance when the diameter d of one from them is relatively to the diameter D of driven roll great and when additionally the maximal grain size of grist 50 is not great, to adapt the setting of at least one milling roll, for instance the second milling roll 2 such a way, that it will be braked.
• milling rolls 1 , 2 , 3 have not to be the same and they can be adapted to the working conditions in the individual milling steps.
• equipment for creation of desirable pressure forces are not to be the same and they can be adapted to the working conditions in the individual milling steps.
• Pi , £ 2 , £ 3 can be adapted, or at least one from them such a way, that its value will be periodically changing.
• the middle pressure more roll presses according to the invention can be used as integral part of technological equipment at mass production of powdered materials, especially at milling of materials with different granularity and great range of grindability, for instance as a part of cement production, at production of cement clinker with cinder addition etc.

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

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Publications (1)

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Cited By (5)

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Citations (6)

• 1999
  • 1999-03-19 CZ CZ1999999A patent/CZ292489B6/cs not_active IP Right Cessation
• 2000
  • 2000-03-14 WO PCT/CZ2000/000015 patent/WO2000056458A1/cs not_active Ceased
  • 2000-03-14 SK SK1418-2001A patent/SK284707B6/sk not_active IP Right Cessation
  • 2000-03-14 BR BR0010772-7A patent/BR0010772A/pt not_active IP Right Cessation

Patent Citations (6)

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