SE202986C1 - - Google Patents

Description

Inventor: H Hardinge Priority Required January 8, 1960 (USA) The present invention relates to a process for successively reducing the particle size of solid material in coarse grinding and fine grinding steps, in which the material discharged from the coarse grinding step is sorted into at least one coarse fraction and a semi-finished product using fine-grained fraction. This process is particularly distinguished by reducing the particle size of the sorted, fine-grained semi-finished product in the fine-grinding step with the aid of grinding bodies consisting of a selected part of the sorted, coarse-grained material from the coarse-grinding step.

When using drum mills and especially stone grinding mills, where the mining goods are led to the mill and grind themselves, it has in many cases, which to a large extent resembles the goods treated in the mill, been shown to form an undesirable excess of relatively coarse pieces or stones, thereby reducing the capacity of the grinding plant. In many cases, the throughput, especially in stone grinding mills, can be improved if one predates predetermined proportions between different grain classes, which have been shown to give maximum efficiency in the production of fine products. there comes the Iran mine. When using known types of drum mills and especially stone grinding mills, it has not previously been possible to achieve such predetermined and desired proportions between different grain classes in the mill to achieve maximum throughput when discharging the desired type of fiat goods Iran mill.

In order to eliminate these disadvantages and shortcomings in existing and earlier use of plants and procedures for grinding solid goods to desired grain sizes and to achieve other improvements in reducing solid goods to desired grain distribution, suitably during uses of mills and special mills. The main object of the present invention is to provide a new and efficient method for grinding solid goods, suitably using a primary mill and one or more secondary mills contained in a grinding plant, which essentially operates as a unit and has a feeding, classifying or sorting mechanism, which can be controlled manually or automatically to achieve suitable installation and regulation of the operation of the milling plant to achieve a maximum amount of goods with the desired grain size and especially linen goods with the lowest monthly operating costs. • According to the present invention a 2 mill, in which solid goods are fed for grinding, which plant can be characterized in that the mill is provided with an installable discharge device, which is designed and arranged so that the Iran mill directly discharged the goods liar a relatively coarse goods to intermediate goods and fiat goods, which can be varied as desired according to the installation of the installable discharge device.

The grinding bodies are generally formed wholly or partly of the grinding material itself and are distributed on primal and secondary mills, either manually or automatically, in order to obtain optimum results in a circuit comprising all the mills used.

If a primer mill is used in a plant to grind down the coarser fraction of the goods fed into the mill, after which the product from the primary mill in whole or in part and with predetermined, desired proportions between different grain sizes is fed to another mill, which can be considered as a secondary or grinding mill. Means are further provided for regulating the feeding of the goods between the different mills, so that the required grinding bodies, since the bodies obtained from the primary mill have been consumed during the repainting in the secondary mills, are replaced from the goods fed into the plant or from the primary mill. compensation is regulated manually or automatically according to the operating conditions in the primal or secondary mills or rams.

According to the invention, a surplus of grinding bodies from the primary mill is further used in the above-described secondary or grinding mills, which grinding bodies are usually quite rounded, so that they become ideal for use as round grinding bodies in predetermined, regulated quantities in the grinding plant's secondary or grinding mills.

The invention will be described in more detail below with reference to the accompanying drawings, which show by way of example some embodiments. Fig. 1 is a schematic, partially cut-away side view of a mill installation constructed in accordance with the present invention. Fig. 2 is a schematic side view of a mill installation on a smaller scale than according to Fig. 1 and according to another embodiment. Fig. 3 is a partially cut side view on a larger scale through a primary mill, which was used in the plants according to Figs. 1 and 2. Fig. 4 is a section along the line 41 in Fig. 3. Fig. 5 is a partial section through a part of the primary mill shown in Fig. 3, wherein a lifting and clamping rust section has been deposited here to form an outlet for larger grinding bodies which are released according to Fig. 3. Fig. 6 is a partial plan of the inside of the mill end seen against that of line 6-6 in Fig. 5 represented the plane and shows as an example four different embodiments of the outlet hatches between the different grids. Fig. 7 is a partial sectional view taken along line 7-7 of Fig. 5. Fig. 8 is a partial vertical section through the discharge spirit of the primary mill shown in Figs. 1-3 on a larger scale than in any of these figures to show details in Figs. an embodiment of a screening device for the goods, which is discharged from the primary mill. Fig. 9 is a section along the line. 9-9 in Fig. 8. Fig. 10 is a vertical section through another embodiment of the primer mill and the screening device, which receives treated goods from the primer mill. Fig. 11 is a section at right angles to the section according to Fig. 10 along the line 11-111 mentioned in the figure, wherein a part of one end of the printer mill is the away edge in Fig. 11, so that details inside the mill appear. Fig. 12 is a circuit diagram of an automatic electrical control system for controlling various controllable operations in the plants shown in the preceding figures.

The plant according to Fig. 1 is intended to illustrate the basic principles according to the invention. This plant can work with vateller dry grinding. The plant can further operate in a closed or open circuit with screens or sorters.

The plant according to Fig. 1 comprises a feed pocket 10 for the primary mill 12. Pet goods to be ground are fed from the box 10 by the belt feeder 16 rach routed by so-called gritty goods and are very heterogeneous, through a discharge opening which can be installed with a door 14. . The belt feeder 16 can operate at an adjustable, undesired speed to lead the goods to the feed mill 18 of the primary mill 12 in predetermined quantities. The belt feeder 16 is driven by an electric motor 20, so that the desired feed speed to the chute 18 is obtained by regulating the speed of the belt 16 and possibly installing the door 14.

The primer mill 12 is suitably of the drum type and rotates about shaft journals 22 in lampy, not shown bearings, the mill being driven by a gear 24 from a lamp transmission, so that the primer mill 12 rotates at the desired speed of ordinary salt at mills of this type.

Fig. 3 shows the mill 12 in the Lorre scale in Fig. 1, and certain parts of the interior of the mill are shown. The details and operating characteristics of the mill are described in more detail in U.S. Patent 3,078,049. The mill 12 was suitably used as a stone grinding mill, without, however, the invention being limited thereto. In addition to ordinary rust plates, the grinder 12 is provided on the inside with elongation rings 26, which ensure a transverse distribution of the different grain classes, as the grinder 12 rotates about its axis, for grinding the raw material fed through the Hunan 18.

Substantially radial tensioning and lifting gratings 28 are arranged at one end of the mill and co-operate with axial tensioning and lifting gratings 30 around the inside of the cylindrical part of the mill. the second end of the feeders has an annular space 32 between the segment-shaped sight plates 34 and the outer end 36 of the grinder. Iran extends the deflection ring 26 of the mill and substantially to the inside of its cylindrical part, as shown in the lower part of Figs. 3, 5 and 6. The grids are distributed in the peripheral direction.

WHEN the raw material to be treated is introduced into the mill 12, it is tumbled by being lifted by the various lifting grids during the rotation of the mill. The goods are also deflected transversely and in other ways separately by the deflection rings 26, which extend inwards from the opposite ends of the mill. The larger pieces serve as grinding bodies, which grind down the smaller grains and themselves are gradually reduced to the size of the stone grinding mill. The grain size of the goods is gradually reduced until the goods can pass through the slots 46 in the sight plates 34 and thus be sieved, after which it comes out into the annular space 32. The goods are then lifted by exhaust plates 42, so that when it is lifted it will fall free from the cavities between the discharge plates 42 and deflected by the outlet cone 44 to be discharged through the discharge cone 48.

During normal operation of a mill of this type, the width of the screen slots 46 will serve as a separator for controlling the size of the product discharged from the mill. The slots 46 are usually about 9.5 mm wide and the gap 50 between the edges of adjacent grid plates 34 is approximately 76 mm. These gaps 50 are normally closed by the rust sections 38. However, according to the present invention, a predetermined number of the sections 38 of the predetermined stalls in the various slots 50, as shown in Fig. 6, are taken to form further discharge slits of predetermined width and length. for achieving the desired variable output. These spaces pass through the desired amount of larger and rounded pieces with a maximum dimension of 76 mm as well as some medium-thick and fit goods, as shown in Fig. 5. In this figure, larger pieces 52 ph are shown around sides of the sight plate 34, whereby it one piece is located in the space 32. These pieces 52 as well as medium-coarse and fine products which fall out into the space 32 are discharged from the discharge cone 48, i.e. the mill 12 rotates. Under normal circumstances, however, according to the present invention, the goods pH below 76 mm which passes through the screen openings or slots 46 will preferably constitute the main part of the discharged goods. If extra grinding bodies, for example bullets, are used in the primary mill, and should be kept in it, their size should exceed the maximum dimension of the openings.

The four different configurations of the gaps 50 and locations of the rust sections 38, shown in Fig. 6, are primarily intended to be illuminating only and not to show the preferred way of arranging such openings. If this proves to be advantageous, such a heterogeneous design of the spaces can be used.

With the possibility of regulating and distributing the openings 50, shown in Fig. 6, the forwarder can empirically determine the most efficient location of such discharge openings for achieving the desired discharge of grinding bodies with a maximum dimension of, for example, a maximum of 76 mm, as well as medium coarse and fine. goods, which may pass through the openings 50. In Fig. 4, the openings 50 are shown closed with a spindle and lifting grate 38, while Fig. 7 shows the opening 50, which is formed when the rust section 38 is removed.

The goods mixture 54, which is discharged from the mill and consists of grain with a size of, for example, a maximum of 76 mm, where the stone pieces 52 represent the largest grain size, and down to less than 3.2 mm, which have passed through the screen slots 46, are discharged in a drum sight 56.

As shown separately in Fig. 8, the drum screen 56 consists of an outer, cylindrical screen 58, which is suitably connected to the outlet of the mill 12 and rotates with the mill, as well as the inner, cylindrical grid screen 60 of the drum screen. the size. nr4, sa. that goods on. slightly less than 6.4 mm can pass through the screen, and that the parallel bars in the grid screen 60 have an inboard distance of 25.4 mm. As can be seen from Fig. 8, goods 62 having a grain size below screen No. 4 will be sandwiched between the rods 60 and through screen 51 and fall into a funnel 64, while goods 66, the grain size of which is between 25.4 mm and sieve No. 4, will not pass through the sieve 58 but in the stable is discharged from its outer dude to another hopper 68. 4 Inside the hopper 68 there is further entrance hopper 70, which has a discharge chute 72. In one second and on one side of the top of the gutter 72 there is an installable, distributor tongue 74, which can. foras till onskat right in the rannan. Of these layers, some with broken lines are shown in Fig. 9. The tongue can then be installed to cut off -Desired ming]. 76 of goods between 76 and 25.4 mm, it is discharged from the outer spirit of the grid drum 60, so that one thereby regulates the amount of such goods, which is diverted from the funnel 68 to the lower spirit by a goods elevator 78, see fig. 1, to during fall through Another 80 return from the upper spirit of the elevator 78 to the feed trough 18 of the mill for further grinding. However, if the tongue 74 is installed 'anxiety to Eiger in Fig. 9 in its one andidge, essentially alit gads in between. 76 and 25.1 mm to be deflected to the discharge annulus 72 for one or more of the following spirits. attachment to the inlet mandrel 84 to a second or re-milling mill 86, which is drum-type and mounted in lamp shaft shafts 88 for rotation about its longitudinal axis. The usual bearings used for storing ram mills 12 and 86 are excluded from the various figures in order to make them more harmful. The grinder 86 is driven by a conventional gear including the gear 90 and the gear 92, which is driven by an electric motor 94.

This plant can thus be operated as a complete unit on such a salt that special grinding bodies Mr the auxiliary or needling mill 86 are not required. The operation is simple and cheap and very adaptable. It is possible and very simple that the second size of the anal bodies is changed by, for example, the size of. The openings 50 between the grid plates of the mill, as well as the dimensions of the trowel screen 58 or the grid screen 60 with or without installation of the tongue 74.

All these bodies do not need to be used by others or set up to produce the desired product. It should, however, be appropriate that all conceivable adjustments should be made individually or in combination for the desired financial financing economically and with the least possible power consumption.

As the grain distribution of the purchased goods varies considerably over a long period of time and may require extensive installation on the tongue 74, it may be appropriate to use a leveling pocket 98. Grinding bodies from Another 72 are fired into this pocket 98 by adjusting a tongue 100. The grinding bodies are then fed to the mill. 86 in unwanted mixture with the help of one. separately controlled belt feeder 102. Although some control of the plurality of grinding bodies, which are deflected from the system by installation of the tongue 74 time after time, may be necessary, this only needs to be done at relatively long time intervals, for which the plant is more stable. and ldttare alt control.

The system shown in Fig. 1 can be considered to operate in a closed circuit thanks to the device. the use of the elevator 78 and the return trough 80, a so-called open circuit is shown schematically in Fig. 2. According to this, it is assumed that limp feeders are arranged to lead ragods to the intradescending of the drum mill 12. Its outlet continuously feeds out a mixture of goods, which consists mainly of relatively light goods, which are sufficiently fine to pass through the screen plates of the mill and, for example, have a maximum size of about 8.2 mm. This material is also relatively coarse material below, for example, 76.2 mm and medium coarse material, which is regulated by installing the gaps 50 between the grinding plates of the mill, fed in its entirety either to a limp sorter or separator 104, from which coarse grains and pieces, for example 25,476 , 2 mm, discharged through. Other 106, which, for example, results in a leveling sheet 108. The goods under 25.4 mm and Overview No. 4 are delivered to one. clumsy conduit, represented by line 110 to be inserted into a second or third drum mill. 112, which may consist of, for example, a rod mill or a stone grinding mill, in which larger anal bodies are used, for example between 76.2 and 127.0 mm. Such goods, which pass through sieve No. 4, are led from the separator 104 along another gutter 114 to the inlet of a seloundar or grinding mill 116 of the drum type, which for example resembles the mill 86 according to Fig. 1 for both construction, operation and operation. The abutment shown in Fig. 2 has a considerably adaptable shape which differs greatly from the incorporation of the intermediate mill 112. The product from this mill is installed so that youngsters respond to the one desired for the second mill, for example so that it passes through screen No. 4. Then the goods has been ground down to this grain size in the intermediate mill 112, it is discharged to the line 114 to be fed to the second or unmilling mill 116.

Before the secondary mill 116 should be sufficiently lined with grinding bodies, Nati-Met is fed by larger pieces into the storage pocket 108 at the desired speed from the same to the line 114 to be inserted into the secondary or grinding mill 116, in which a finished product of desired fineness is produced.

The various sizes of the final product or intermediate in the mills of Figs. 1 and 2 are given by way of example only and it is not intended to limit the present invention to these sizes. Relatively widely varying grain sizes can be used to form the maining plants described above.

Figs. 10 and 11 show a drum mill 118, which differs slightly from the woman. the mill 12 according to Figs. 1 and 2. The mill 118 is a primary mill and is as previously intended to illuminate a stone grinding mill or a mill which can use special grinding bodies, for example steel balls, for which reason it is provided with radial lifting gratings 120 at their opposite ends and axial lifting racks 122 on the inside of the cylindrical part of the grinder 118. Conical deflection rings 123 can also be used to ensure mixing of all grain sizes in the goods milled in the mill, after being fed through the feed nozzle 124. the stable to be provided with grids, through which a product of predetermined grain size is fed. as with the grinder of Fig. 1 oak 2, the grinder 118 has a relatively large outlet opening 126 which extends coaxially through the shaft pin 128. The grinder is rotatably mounted by means of two Adana shaft pins, which are mounted in a flexible position, with respect to the resilience. not shown A discharge chute 130 extends through the circular discharge opening 126 and is provided at its upper spirit with a grid 132. It prevents too large pieces from passing to the chute 130.

The discharge chute 130 is suitably at least a transversely curved pivot about two opposite pivot axes, which are pivotally supported by a buck 136, which is fixed to a lamp surface. An installation means in the form of a radial arm 138 Tried a head 140 with a bag-shaped slot at the outer end Or wedged or Mst ph other salt at its upper dude in one of the brackets 142, which are directly fixed in the groove 130. A scale 144 may be arranged on the head 140 oak unloaded against one. fixed point 146 ph buck 136. A laser hard weld in the form of a bull 148 engages the slot 140 and slots of the head, when it is tightened, the head, the arm 138 and the groove 130 in the desired position, that the grille 132 is installed in one of several tankable layers. , which is shown in broken lines in Fig. 11.

When the gutter is installed in a suitable position, the goods mixture 150, when it falls into the curved paths shown in Fig. 11, will end up on the grid 132, whereby pieces which are stone at the gaps between the bars of the grid are advanced back to the mill, while the goods passing through the gaps fall out along the gutter 130 to the screen 152. The stiffer pieces, which are screened hard by the grid 132, are reduced to smaller pieces by blows and nothing, until they finally pass through the grid. If this is part of the preferred embodiment of the invention, it can be ruled out, especially under such conditions, that the goods which are led to the mill, either as received from the wildebeest or prepared in some way, have a much larger, largest grain size. that it can pass through the grid, or also. the groove 130 is pivoted sufficiently to the side to avoid any falling pieces, which are too large to be used as grinding bodies.

The screen 152 according to Fig. 10 is an example of another of the selectable devices which can be used to divide the goods into different grain classes. However, if desired, a drum screen of the type shown in Fig. 2 or any other device may be used.

The screen 152 has several spaced, parallel and sloping rods which form a grid 154. The gaps between the rods 154 of the grid pass through the rods, which are usually rounded, as they are discharged from the mill and have a minimum dimension which is 2.5 cm. Pieces 156, which have a size between 7.5 and 2.5 cm, are discharged through a trough 158 to be returned to the mill with suitable lamps (not shown), which may be of the type shown in Fig. 1, or fed to a storage pocket. for delayed and regulated feeding to an auxiliary or grinding mill or to be led directly to an auxiliary mill in the manner described in connection with Fig. 1.

Another screen 160 with a mesh size of, for example, No. 4, Or arranged below the grid 154. Goods 162, which have a grain size between 2.5 cm and screen No. 4, will thus be fed along the screen 160 and delivered to a trough 164, while sub-grain 166 maths at the funnel 167. This goods may be finished, IF it is sufficiently fine-grained for the intended purpose, or the funnel 167 may also, if the goods are to be ground ph new, stand in connection with the inlet to a secondary or milling mill, such as the mill 86 in Fig. 1 or 116 in Fig. 2 for further mailing.

In the case of stone-milling mills of the type shown in Fig. 10 and 11, it was found that in the mill the treated, larger pieces used to move again in a closed path, 'Km lies the inside of the relative mill. speed this path stretches between about 6 o'clock and 9 o'clock. 6 Most of the medium-coarse and fine-grained goods move in a path together -with these larger pieces and are crushed grad-xis by women, while the pieces themselves are also reduced to their size These smaller pieces are usually lifted higher inside the grinder. the finer grain to fall along curved paths, as shown in Fig. 11. The goods SOill is in the team at 11 o'clock or in some cases even away from the team at 1 o'clock consists entirely of the yar number of the mill, the density of the goods and the grain size hu lovely of smarter pieces and finer grains.

Since the different grain sizes move in different paths in a drum core of denim type, Annan 130 can be swung to different layers and thereby receive goods with widely varying grain sizes according to their laze in relation to the falling goods. The grid 132 can be replaceable, so that grids with different gap widths can be mounted.

In particular, Fig. 11 further shows that by suitable installation on the grid 132 in the mill it is possible to prevent the grid from being hit by very heavy supports, except accidentally. If the grid and the ridge 130 by the spirit of the ridge are sewn to the outermost surface of the hoger, as shown by broken lines in Fig. 11, only finer grains are suspended. Even more important is the fact that the layer 130 of the gutter 130 and the grate 132 in relation to the mill's hire can be galvanized while the mill is working, for example. change in the species ay the goods which are fed into the mill, for example in the grain distribution. By installing the gutter 130 layer in an appropriate way so that my new conditions, the throughput of the grinder can be increased to a maximum, without the grinder having to be stopped.

A comparison of the embodiment of the primer cores and the installable leveling means according to Figs. 10 and 11. The tiled mill 12 in the embodiments according to Figs. the latter embodiment, and that oscillation of the gutter 130 in the first embodiment will give approximately the same effect as the removal of some of the lifting rust sections 38 concerning the size of the different zones and being incorporated into the mill. These ram forms, however, are essentially examples of suitable constructions for discharging an undesirable amount of coarse grinding material from a primer mill together with finer goods, which are to be ground further on the coarser material in a second core. Other constructions for this purpose may be considered within the scope of the present invention.

Since the secondary or regrinding mill in a milling plant of the general type described above operates under the use of mills which have been formed in the primary mill and consist of the same type of goods as that processed in both the primary and secondary mills, not only the medium coarse and finer goods In the mills but also the grinding bodies themselves, so that they must be replaced. Grinding bodies, which consist of the same goods as that which are soin males, are usually not as hard as balls or metal balls, which are supplied separately, but are scraped down and consumed much more rapidly. Most of them must be supplied in a considerably larger quantity, which is the case, unless the ground goods are of a very unusual type. If suitable grinding bodies can be obtained directly from the grinding plant itself without the use of external sources or the use of metal balls, the grinding plant will obviously be much cheaper to operate and entail a great advantage for the user of such a plant. .

The various installations of some elements of the plant described above have been stated above to take place mainly manually. This is the case with regard to the regulation of the feed mill 14 in the primary mill, Fig. 1, the speed of the belt feeder 16, the installation of the distributor tongue 74, the installation of the tongue 100 at the same speed as the feed belt 102 for grinding bodies in the embodiment of Fig. 1. anyanda automatic means for maintaining the operating conditions at an optimum or at the flag of another Desired speed to minimize the need for manual install-fling, since the plant once has instances of desired operation to produce desired products at desired speed. When using automatic means, one must take into account several variables as well as the parts of the template that are regulated to be reached by the desired breaths. In applying the present invention, for this purpose the following exemplary components may be utilized in one or the other form in the various plants described above and installed to achieve desired, controlled operating conditions for the entire mill plant: 1. Control of the supply to the primer core . 7 Variations in the motor power of the secondary or re-grinding mill under different load conditions.

The sound level of the second or re-grinding mill, which shows different load conditions.

The installation device for regulating the supply of grinding bodies and the feeder to the grinding body stock, if used, for regulating the grinding of the grinding body and the supply of grinding bodies to the secondary or repainting mill.

The content of upper grains or coarse components in the Iran secondary or milling mill for regulating the total throughput of the primary mill circuit and the feeding of mills to the secondary or milling mill, or combinations thereof.

Other phenomena in the plant, which were popular in the art and also act in such a way that they can be used to act on devices for changing the grinding. The mill grinding technique is the edge in complete stone grinding, where all grain grinds are ground at the same time, or in the partial stone grinding, where flint balls are used to grind relatively fine grain sizes, to, among other factors, affect the operation of different mills, at or near the optimum capacity for detoxification of product of desired type. Regarding the operation of secondary or re-grinding mills in the types of grinding plants described above, it has been found that: A reduction in the noise shows too much fine fraction in comparison with the coarser fraction in the mill and that the proportion of fine fraction to coarse fraction is too high, and that the inside of the mill may have a bulge.

A Wining of the sound indicates an excessive supply of grinding bodies or a decrease in the feed rate or baggage.

A decrease in the normal power consumption can indicate either a reduced speed in the supply of grinding bodies or possibly too much grinding body filling. This can occur if the so-called normal mill load is very close to the maximum power that the mill can consume.

A dimming of the power consumption above the so-called normal indicates an abnormally large target body filling for a given power consumption, if this is so far below the maximum achievable power consumption that a certain variation is possible.

A caning of the power consumption while simultaneously reducing the noise normally indicates too much grinding body filling as well as too much lint material in the mill and / or possible coating of the inside.

An increase in both power consumption and noise normally indicates excessive body filling and a lack of fine goods.

A reduction in both power consumption and noise may indicate too small or possibly too large a body filling, the latter if the grinder works too close to the maximum power consumption, or if the grinder has too high a content of fine goods.

A reduction in power consumption. and Mining of the sound normally indicates a reduction of the grinding body filling, if the normal power consumption is far below the maximum. However, if this were not the case, the reduction in power consumption and the increase in noise could also indicate excessive body filling. In the back cases, there is a question of a deficit of fine goods in the mill.

A wining of the amount of top grain from the secondary mill or grinding mill indicates either too much feed to the primary mill and to the secondary mill or a deficit of grinding bodies in the secondary mill. Under such conditions, an increase in the supply of grinding bodies to the secondary mill will remove some of the medium-coarse material from the primary mill and balance the load in it without changing the feed rate to the primary mill, if other conditions are normal.

The above-mentioned symptoms of the essential variables in the operation of the various components and the causes of such conditions, which have usually been clarified during long-term experience, can be used additively or subactively and automatically to correct the grinding conditions. These symptoms can be used to have others installed by the various components mentioned above either simultaneously or separately, as required by the condition. This change can be done automatically.

The special conditions during the entire operation, such as the feeding conditions and other variables, are only observed during a series of preliminary experiments and with manual installation for observation and correction. The normal limits are determined Life under this manual control of different, adjustable components, and the harmless, optimal operating conditions under different circumstances are recorded and determined. An example of a control circuit for automatic installation, control and operation of the above-described grinding systems is shown in Fig. 12.

When the grinding plant is first put into operation, the feeder for the primary mill is installed so that the mill is made to operate normally under prevailing conditions. The mechanism for wetting or separating grinding bodies from the outlet of the primary mill in the circuits described above is installed so that the grinding bodies taken out from the primary mill are led to the secondary or grinding mill at about the desired speed, suitably in accordance with the consumption of the mill. in the secondary mill. The main control devices, which are used to keep the conditions constant in the circuit, especially in the secondary mill, react to the sound of the secondary mill, power consumption and top grain production in a somewhat appropriate way. These three controlling factors or phenomena constitute examples of operating conditions, which can be used to indicate certain conditions in the mill system in order to influence a relay system, after they have been installed to come into operation at desired points. Other known conditions and suitable control devices can be used within the scope of the invention.

The relay system should work properly, then. the sound of the secondary chamber reaches the noise level that it wishes to maintain. The relay system continues to operate, as the motor that drives the secondary chamber has a predetermined power consumption at night. It is also affected when the upper grain production of the secondary mill reaches a proportion of the whole product, which is considered optimal for a given condition.

The control circuit according to Fig. 12 mainly comprises standard components and suitable relay systems, installable medals for adaptation to any given, desired condition, indicators and displacement elements to eliminate fluttering or too rapid reaction, especially if there is a propensity for instantaneous changes, ie average conditions. Since standard elements are different in this circuit, it should be redundant to give. in a more detailed description of Tank elements, but these are described in general terms and information regarding their effect is laminated, so that one should be able to understand the effect in the circuit, as desired, for regulating the main variables automatically after manual regulation and installation in the beginning. The action of the various feed mechanisms and classification or separation mechanisms as well as other elements in the whole plant, as mentioned above, are mentioned in connection with the following detailed description of the circuit according to Fig. 12.

In a lamp-like position in relation to the secondary mills 86 or 116, see Figs. affected by the power level. The outgoing goods Iran the secondary mill 86 is led to a gutter 174, see Fig. 1, to be discharged on a suitable screening apparatus 176, which comprises an inclined screen 178 with the desired mesh size. Through this sieve the fine goods pass to be delivered to a product line 180.

The overcom product, which does not pass through the screen 178, was added to a scale, which is represented by the band 182, which is mounted on a lamp indicating and recording apparatus of some lamp type. The belt delivers the goods to a trough 184, which leads the Overkorn product either to the second medal outside the plant or to a suitable lifting mechanism to be returned to the primary or secondary mill for repainting. The variation in the weight of the top grain product fed by the belt carriage 182 is utilized, as shown in Fig. 12, to actuate an apparatus 186 which responds to the weight of the top grain product.

Tongue 74 was first assumed to have been stains manually in the desired team. By manually fitting the resistor 188 in the main line to the installation mechanism 190 immediately at the point of adjustment of the hose 74 through the arm 192, which is connected to the damper by a long 193, while all other devices are also assumed to be installed at the working point, it will wanted the degree of change between the various devices, such as the device 170, which is sensitive to sound, the device 172, which is sensitive to the power consumption of the secondary grinder, and the device 186, which is sensitive to the formation of top grain product in the secondary grinder, to be controlled by each resistor 194, 196 and 198. All these units are coordinated and each of them is variable. Each unit can be installed or prevented from affecting the circuit as desired. The variability of these resistors makes it possible to select the degree of change desired in the circuit of each device, since one device usually has a greater effect on the circuit than others according to the conditions.

If the supply of grinding bodies is to be controlled only by installing the tongue 74 in the screen mechanism 56 of Fig. 1 and the grinding bodies are led directly to the secondary mill 86, a current counter 200 is installed so that the line 204 is connected to the line 231. However, the current generator 200 to connect the lines 202 and 204, so that the sensing devices control the motor 206 of the conveyor belt 102 for regulating the grinding body supply. When the grinding bodies are fed over the pocket, the tongue 74 is manually installed in a suitable position to hold a Monad of grinding bodies in the pocket and then manually adjusted one after the other according to the circumstances. Tongue 100 opens ocksh. manually. The variable resistor 188 may be shunted out of the circuit as the assay is installed for automatic control, as desired depending on the use of one or more of the other resistors 194, 196 and 198, which vary the degree of control through the apparatus 170 (sound). ), apparatus 172 (power) and apparatus 186 (upper grain production) or any combination thereof.

If the conditions in the entire grinding plant are such that completely normal operation can not be maintained due to excessive variations in the input material to the primary mill, which variations have a strong effect on the supply of grinding bodies, one can also use an auxiliary control, which also controls the motor 20 to the primary mill feeder in the embodiment of Fig. 1. This will help to maintain the supply of grinding bodies required in the secondary mill circuit and supports the operation of the other devices which normally control the primary mill, as generally indicated by the circuit 232. These devices are not shown, because they are valued in the art of regulating the operation of the primary mill depending on the sound or the power consumed by the primary motor drive motor, or other symptoms. These latter control devices do not have a lake in the present invention, which, on the other hand, is a means of further supplementing the control of the primary mill, if desired.

The above-mentioned auxiliary control of the feed of the primary mill is shown by the contacts 208, 210 and 212, which cooperate with other contacts 233, 234 and 285, which form part of the control system for the grinding bodies as described above, and in turn have their own medals for achieving the degree of change, which is desired by the resistors 214, 216 and 218, as ° Asa none in the circuit of the motor 20, which drives the primer of the primary mill. Any of the contactors or all of the contactors can be connected to or disconnected from the circuit after the induction with the aid of the currenters 220, 222 or 224 for the primary mill supply circuit, or the currenters 236, 237 or 238 in the circuit for regulating the grinding body supply. The speed of the primary mill feed motor and the claimed feed rate are controlled by the apparatus 240, which is of the ordinary type, and the variable resistor 239 together with or independent of the other resistors 214, 216 and 218.

Under normal operating conditions, the sound of the secondary mill through the apparatus 170 and the resistance circuit 194 controls the supply of grinding bodies to the secondary mill, as the sound deviates from the preset, desired sound level. At the same time, it can also control the supply to the primary mill, if the current switch. 220 Open.

The power consumption of the secondary mill motor can be used with the aid of the apparatus 172 to regulate the supply of the grinding body to the secondary mill, if the resistor 196 has instantaneous to operate below the maximum power level. This apparatus can also be used to control the supply to the primary mill, if the current switch 222 is opened.

The secondary mill's production of upper grains can, with the help of the apparatus 186 and the resistor 198, be used to supply the second anal body to the secondary mill, if the upper grain production deviates from the desired one. With the means for detecting the upper grain production, it can be installed that the second supply to the primary mill, if the switch 224 is opened.

Under certain abnormal conditions, the hardness of the goods or the grain distribution at the end of the primary mill in relation to the throughput of the secondary mill may cause one or more of the combinations of controls to act on a different salt than that described above. Means are provided for reversing the mode of action of any or all devices used, if desired. Each device inver, car the operation in its entirety and there placed its circuit, that it can be used or not used as desired and in habit Unwanted degree in connection with the Other control devices, as shown, which oeksa can trade in funk-Lion at the same time. The sound-sensitive device can thus be used and installed to influence the feed rate to a degree of, for example, 15%, while another device, such as the power consumption-capable device, can be installed to affect the feed rate only by 5%, and another flake other device. ails were not used for one reason or another, which in many cases can only be determined empirically. At the same time, for example, the apparatus capable of overgrain production can be connected to only the second supply to the primary mill or it can also be connected to the secondary mill circuit at the same time, that it neutralizes the influence of other control devices, by switching the switch 241 in the apparatus 186 up make or vice versa.

The work process in drum mills under different conditions varies considerably, in that it, which has a very strong effect on the power consumption in a situation, has no appreciable effect on the sound or the production of top grain in the secondary mill and vice versa. However, the man may choose that, under certain conditions in grinding types of goods, which differ considerably in their properties, all three or any of the three above-mentioned regulating factors, namely sound, power consumption and top grain production, may vary considerably in system and in some cases compensate each other and in others have a cumulative effect.

Although the invention is primarily concerned with the use of a stone grinding mill as the preferred type of drum mill, the mills may be of the combination type, using at least in part the other or the material being ground, for example by adding balls to the primary circuit or the secondary circuit according to need or desire, as is sometimes the case in mills of these types. While the above-mentioned grain classes can be considered normal, one can also choose strongly different grain classes and sizes of the grinding bodies under different operating conditions. Furthermore, other means can be used to separate parts of the coarser fractions or grinding bodies of the primary primer from those described above.

You can also apply wet grinding or dry grinding. If the entire plant operates in a closed circuit, this normally comprises a primary mill, which works in its own closed circuit and a secondary mill, which works in its own closed circuit. Survivors from the secondary mill can also be led back to the primary mill if desired or also only a part of the intermediate product or the intermediate grain classes from the primary or secondary mills can be taken out of the circuit completely to be treated separately, if desired.

Furthermore, other means can be used for sensing the operating conditions of the secondary or grinding mill than those which have been shown and described, wherefore the specially mentioned indicating and recording apparatus and installation apparatus, which have been described in the plant in its entirety, constitute only examples and jokes as a flag limitation.

Although only a single secondary mill is used in the plant and processes described above, with the possible exception of the use of the auxiliary mill 112 in the embodiment of Fig. 2, according to the present invention additional secondary mills can be used which receive goods either from the primary mill or a leveling pocket connected to the outlet of the primary mill, or receiving goods frail the secondary mill shown in the described plants, if the use of such additional secondary mills proves desirable and necessary to obtain a desired product of some solid material, which may require the use of additional auxiliary grinders, even if the sides are not shown specifically in the drawings.

The invention also encompasses the use of other components in a grinding circuit using several control devices than those described in more detail above, for example if the pocket 98 is used as the main feeder for the grinder 86 and does not necessarily constitute a means for supplying grinding bodies only. Under such conditions, the control of the feed with the feeder 102 may be controlled by one or more of the devices in the overall control system of Fig. 12 in combination or separately according to the operating conditions of the mill 86, to provide a coordinated control to achieve optimal results.

By "stone grinding" is meant the use, in whole or in part, of the goods being painted, as its own grinding medium. By "mining goods" is meant a mixture of goods, which normally comprises coarse, medium-coarse and fine fractions, of which the coarser ones are present in sufficient quantity to grind themselves jammed & rich grain sizes, which none in the goods, although certain grain sizes can be eliminated or partially treated separately.

The embodiments described above can be modified without exceeding the scope of the invention.

Claims (17)

Patent claims; A method for successively reducing the particle size of solid material in coarse grinding and fine grinding steps, in which the material discharged from the coarse grinding step is sorted into at least one coarse-grained fraction and a semi-finished product using fine-grained fraction, characterized by reducing the half-size particle size of the in the fine grinding step with the aid of grinding bodies consisting of a selected part of the sorted coarse-grained material from the coarse grinding step. 2. A method according to claim 1, characterized in that the material discharged from the coarse grinding step is also divided into one. medium coarse fraction. 3. A method according to claim 1 or 2, characterized in that the selected part of the sorted coarse-grained material constitutes a smaller part of the total amount of material which is discharged from the coarse grinding step. 4. A method according to claim 2 or 11 3, characterized in that the relative amounts of the three fractions produced in the coarse grinding step are controlled. 5. A method according to any one of claims 1-4, characterized in that the selected part of the coarse-grained fraction is taken from a storage container (108), to which the coarse-grained fraction is fed. 6. A method according to claim 4 or 5, characterized in that the control of the relative amounts of the three fractions produced in the coarse grinding step and the selection of the part of the coarse-grained fraction fed into the fine grinding step is carried out with regard to the operating conditions in the fine grinding step. 7. A method according to any one of claims 1-6, characterized in that all material from the coarse grinding step with a grain size of the intervals which are not fed to the fine grinding step is returned to the coarse grinding step for further probe division therein. Device for successively reducing the grain size of solid material in coarse grinding steps and fine grinding steps according to any one of patent claims 1-7, which comprises a first (12) and a second (86) rotating mill, in which resp. grinding steps are performed, a means for sorting the material discharged from the first rotating mill (12) into at least one coarse-grained fraction and a fine-grained semi-finished fraction, characterized in that it is provided with means (100) for selecting a part of the the coarse-grained material from the coarse grinding step, which part serves as grinding material in the second rotary mill, and means (82) are provided for feeding this part together with the fine-grained semi-finished fraction to the second rotary mill (86) for further probing the fine-grained semi-finished product. . Device according to claim 8, characterized in that it is provided with means (68, 78, 80) for receiving material coming from the frail sorting means (56) with a grain size of all intervals which are not supplied to the second rotating mill (86 ), for returning this material to the first rotating mill (12) to further reduce the grain size therein. Device according to patent claim 8 or 9, characterized in that the first rotating mill (12) is provided with an installable discharge means (46, 50 or 130, 132), which is designed in such a way that the free mill directly discharges the material exhibits a ratio between coarse-grained grinding body material known as siclan and fine-grained semi-finished products as well as co-coarse material on the other hand, which can be varied as desired depending on the setting of the discharge means. Device according to claim 10, characterized in that the installable discharge means comprises discharge finger (50 or 132) of a size which allows discharge Iran the first rotating mill of the coarse-grained grinding body material, which discharge openings can be given varying layers. in the mill. 12. Device according to claim 11, characterized in that the total surface of the discharge openings (50) is variable. Device according to claim 12, characterized in that the installable discharge means comprises grid sections (34), which allow the passage of the fine-grained semi-finished product and medium-coarse materials with a predetermined maximum size in Iran the first rotating mill, and the discharge openings (50). ) Concerns arranged between these grid sections and Conveyors provided with tacking means (38), which can be varied in number and position and achieve the desired variability of the total surface and the layer of the discharge openings. Device according to claim 11, characterized in that the installable discharge means comprises a gutter (130), which at its one end, which extends into the mill, is provided with sight openings (132), and the gutter Or arranged displaceable in relation to the mill I Or enabling a desired variability in the installation of the layer of the sight openings. 15. Apparatus according to any one of claims 8-14, characterized in that an installed deflection means (100) is arranged between the sorting means (56, 60) and the second rotating mill (86) for deflecting at least a portion of the selected portion of coarse-grained grinding body material to a storage container (98), which Or is provided with adjustable discharge means for discharging the stored coarse-grained grinding material to the second mill at a predetermined rate. Device according to any one of claims 8-15, characterized in that the sorting means (56) comprise a material-branching part (74) of the lodge in a falling stream of mixed medium-coarse material and coarse-grained grinding body material contributes to the control of the selected part of the coarse-grained grinding body material. 17. Apparatus according to claim 15, characterized in that the installable lead means (100), and / or the installable input means (102, 206), and / or the feed rate of material to the first 12 rotary mills are automatically regulated. assisted air means affected by the air operating conditions of the second rotary mill, in particular the sound emitted to the air donna, doss energy consumption or the amount of material with grain size greater than the desired one emitted from the mill, or a combination of air two or more of these conditions. Request publications: Patents from Sweden 29,271; United Kingdom 215,595; USA. 1 293 656.