WO2002022269A1

WO2002022269A1 - Improvements in the reversible and not reversible secondary and tertiary hammer mills

Info

Publication number: WO2002022269A1
Application number: PCT/IT2001/000470
Authority: WO
Inventors: Antonino Palmiro Paolini
Original assignee: Mills Patent Management
Priority date: 2000-09-14
Filing date: 2001-09-11
Publication date: 2002-03-21
Also published as: CA2431702A1; PT1322423T; US6955313B2; BR0114134B1; US20040035966A1; EP1322423B1; ZA200302179B; CN1201867C; WO2002022269A9; ES2662595T3; RU2278732C2; CN1455702A; MXPA03002288A; JP2004524133A; BR0114134A; UA73798C2; ITNA20000063A1; AU2001292229A1; ITNA20000063A0; EP1322423A1

Abstract

Secondary or tertiary hammer mill comprising a hopper (10) and a housing (8) in which a first upper rotor (1) with radially arranged hammers (3) and a second lower rotor (5) with radially arranged blades (6) are arranged so that, upon rotation of the rotors, the material to be crushed is thrown by the second rotor onto the first rotor. The number of blades are equal to the number of hammers and the relation between the diameter of the first rotor and the second rotor is 1,5-2:1 if the mill is a secondary and 4-7:1 if the mill is a tertiary mill.

Description

Improvements in the reversible and not reversible secondary and tertiary hammer mills.

Technical field

The present invention concerns improvements in the hammer mills, both secondary and tertiary, reversing and not reversing, for the making of the inert materials, that use a special rotating device of interception of the flow of feeding of the inert materials, endowed with tapered blades with a minor peripheral speed rotary and a small thickness to the free extremity, able to launch the inert materials in discontinuous mode, violently against the front of the hammers and only in the moment in which pass the hammers.

State of the technique To the present state the hammer mills to bump both the secondary and the tertiary, used to the making of the inert material, introduces remarkable problems: elevated percentage of recycling with repercussion on the productivity, high percentage of dust in the obtained product, problems of environmental impact and guardianship of the health of the workers in the environments of job for the enormous quantity of dust that is emitted by the mill in phase of exercise, bad granulometry and polyhedric nature of the obtained product (scarce presence of thin parts with excess of dust), strong usury of the hammers and the armored walls.

The principal cause of ineffectiveness is strong peripheral speed of the hammers necessary to break the inactive material, that doesn't allow an easy passage of the same material on the front of the hammers; because really working to impact with the front of the hammer, in place of the traditional system to crushing (studies performed by the applicant have pointed it), that is resolved all the above-mentioned problems. In the tertiary mills, to be able to arrive to treat the chippings up to thirty of millimeters of diameter, is necessary to arrive to a peripheral speed around the 70 m/s, while in the secondary mills, with a chippings of the order of hundred millimeters at tl too much raise for allowing the penetration of the inert material with those dimensions, in an e; and around the doub] The physical phenon of the operation of a mill is performed, for example of a tertiary mill to two hammers for the production of sand, with a personal computer. As soon as the chippings comes introduced in the mill it is noticed that the hammer, already from the first impact, once taken a certain quantity of inert materials, it interfere with chippings particles immediately superior not hold, it loosens the free fall. It is created, that is, an interference phenomenon between the superior particles not intercepted, whose entity is strongly tied, over that to the aforesaid peripheral speed of rotation (above all), also to the thickness of heading of the hammer and the thickness of the chippings flow of feeding that arrives from the high in free fall. These particles of chippings, don't make more on time to regularize, because of the high frequency of beat of the hammer in the unity of time ( about thirty to the second for the tertiary mills to two hammers). And then, above all when the edge of the hammer begins to become round for the usury, the chippings, practically, doesn't come almost anymore intercepted by the front of the hammer, it refused (it floats) and it is gone to channel among the perimetric circumference of the rotor and the wall armored of the mill, through a space that becomes more and more tightened, thin to be forced to the crushing in a point that depends on the dimensions of the same chippings. From here the necessity to endow the traditional mill of a special register of approach of the armored wall, in comparison to the perimetric circumference of the hammer (to establish the maximum sizing of the inert material from obtaining to crushing and to compensate the usury of the superior part of the hammer).

The results of this traditional system to crushing are, inevitably, everything how much of negative has been exposed to the beginning of the paragraph.

Purposes and advantages of the invention Object of the pr the tertiary ones, reversing and not, for the making of the inert materials, conceived entirely in way new system of making (tc the traditional crushii

Keeping in mind the aforesaid problems that determine the phenomenon of interference and, therefore, the making to crushing(strong peripheral speed of rotation and thickness of heading of the hammer, as well as the width of the flow of fed material), idea has been that to use a special rotating device of interception of the inert material, analogous to that of the traditional mill, but that it had the parts that intercept (blades), characterized by a minor peripheral speed rotary and from a minor thickness of heading; the all, fed by a more narrow flow of feeding. Once intercepted the inert material, it can be launched violently against the front of the hammer. The launch happens in discontinuous way, only in the moment in which the hammer, for which the heading of the same is not struck by the inactive material passes and, therefore, interference is not had among the varied particles of inert material. It is in this way, resolving the problem of the interference with the adoption of an effective device of interception of the inert material, that the impact is assured on the front of the hammer. The reaching of the impact on the front of the hammer brightly resolves all the above mentioned tied problems to the traditional system of making to crushing. The all, perfectly confirmed by the results gotten by the applicant, not only through studies performed with simulations of operation with computer, but also from the tests effected on a prototype of hammer mill realized. We bring, following, such gotten exceptional results, in comparison to the generic traditional mill:

-increase of production from about the double, in comparison to the traditional mills with new hammers, to about the triple, in comparison to the traditional mills with consumed hammers; -nearly nonexistent recycle;

-energy's electric reduction employee to around the half, to parity of production; -knocking dowi

-nearly absence of dust freed by the mill toward the external environment (strong reduction of enviror the environments of -good polyhedric pr

-good granulometry of the inert material, with sands that have elevated percentages of thin parts; a different granulometry can be gotten in operation of the speed of impact (is enough change the pulley of the motor); -reduction of usury of the hammers and armored walls; to specify that such usury, contrarily to how much it happens in the traditional system, it doesn't provoke any inconvenience, relatively to the constancy in fact of production, electric energy, dust, polyhedric nature, granulometry, etc.

Besides definitely resolving, as we have seen, all the big problems tied to the traditional system of making (crushing), this new system (completely to impact) introduces others enormous advantages, that following will be described.

Besides the classical rotor with the hammers, such innovative mills introduce, superiorly, to only some centimeter of distance, a second rotor (rotating device of interception) whose diameter is in operation of the dimensions of the inert material to treat (a little smaller for the secondary mill and very more for the tertiary mill), endowed with special blades in equal number to that of the hammers, sets in phase

(same number of turns in the unity of time) with the principal rotor through special organ of toothed transmission. The principal characteristic of such second rotor is that to receive the inert material from the high, to invite it according to a circular trajectory and to launch it against the front of the hammers of the mill, in almost perpendicular direction to the front of the hammer. How to note from the fig. 1, the vector component second the direction of the speed of the hammer, is of little inferior (as soon as 5-7%) in comparison to the same vector of the speed of throwing. This means that the speed of throwing is gone to almost entirely add, as intensity and verse, to the peripheral^' speed of the hammer that strikes the inert material. Considering that already to the first impact the shattering of the material reaches 70% ab that:

-keeping in mind th rotation of the mill c almost be halved), inactive material, with the principal advantage of an easier and controlled penetration of the same inactive material toward the front of the hammer (we have seen how are to dissuade strong peripheral speeds of rotation towards the phenomenon of interference). In more, in the tertiary mill, this system allows, operating with chippings of small dimension (around 10 mm), to arrive, without decreasing peripheral speed of rotation of the mill (it is not necessary, because the penetration in the rotating device of interception is very easier when the inactive material is small) but making use of the aforesaid additional speed of throwing, to speed ever reached till now (over 90 m/s); the all, to get to impact thin sands, not obtainable with the actual mills to impact in commerce;

-thanks to the throwing of the material almost perpendicular to the front of the hammer, can be reduced, in the phase of impact, the tangential tensions, with consequent better polyhedric nature of the inactive material broken and reduction of dust; -thanks at the most approach of the two aforesaid rotors (only some centimeter) is guaranteed with the maximum precision the reaching of the objective (impact point), with a consequent improvement of the uncontrollable effects in the phase of throwing and impact.

Description of the drawings and way of realizing the invention.

These and other characteristics, as well as advantages, will result evident from the following description to from the enclosed drawings furnished to only indicative purpose and not limitative, in which: the figure 1 shows a transversal section of a generic hammer mills, secondary, reversing, totally to impact; the figure 2 sh< figure; the figure 3 shows reversing, totally to : the figure 4 shows figure; the figure 5 shows the constructive detail of a generic hammer mills, tertiary, not reversing, totally to impact. In the exposure that follows we refer for simplicity of exposure to the secondary mill of which to the fig.l and the fig. 2 with the precise statement that everything how much it will be said it is also worth for the tertiary mill of which to the fig.3 and the fig. 4, having had the sagacity of appending to the fig. l and fig.3, as well as to the fig.2 and fig.4, the same representative numerations of the varied parts of the machine. And then, with reference to the secondary mill of which to the fig.l and fig.2, the principal rotor is pointed out (1) and relative orbit perimetrale (1 '), the protections (cover flywheels) anti usury (2), two (preferable, but they can be also increase of two) hammers (3), the armored walls (4) and all those other parts mechanics presents currently in every mill, that here are not recalled. To keep in mind that, not having crushing, the registers of approach of the armored walls, fundamental for the traditional mills, don't have reason to exist anymore; such walls will be fixed and the most distant possible from the hammers (it is sufficient about fifty millimeters both in the secondary mill that in the tertiary mill). Superiorly, the nearest possible, to some centimeter of distance from the rotor (1 ), there is another of it (rotating device of interception), smaller, that will call secondary rotor (5), with relative orbit perimetric (5'), endowed with special taper blades (6) (the taper facilitates the entry of the material) in equal number to that of the hammers, as well as of two (can be also unique) lateral circular invitations (7) with the edges superior internal beveled (7') and joined (to facilitate the entry of the inert material) tangentially to the peripheral (5'). The carcass (8) of the mill contains everything how much aforesaid. The two rotors i the unity of time (put in phase), through special organ of toothed transmission ( 1 1 ); such organ is endov automatically begin example, to some j occasionally fit. The organ of transmission can be also represented by a simple toothed belt that connects the two aces of rotation endowed with equal pulleys; in such case the belt must be adequately proportionated, so that, following an irregular block of the secondary rotor, can easily be broken, to be replaced. It completes the machine a hopper load (10), that will be most narrow possible, compatibly with the greatness of the inactive material to be treated (about a hundred millimeters for the tertiary mill and the double about for the secondary mill). The hopper is endowed with window (9) for the insertion of the feeder of load. The sizing of a mill, above all as ratio between the diameter of the greater inferior principal rotor and the secondary superior (rotating device of interception) smaller, it depends in first place on the dimensions of the inactive material to treat; such relationship is varying around from 1,5 to 2 for the secondary mills (transformers of crushed stones in chippings) and from 4 to 7 around for the tertiary mills (manufacturing of sand, departing from the chippings). We now pass to the description of the operation of the mill.

The inactive material (crushed stones) from the window (9) of the hopper of load (10), it arrives on the blades of interception (6) of the secondary rotor (rotating device of interception). The height of fall and, therefore, of the hopper, is calculated keeping in mind that, in the existing time between a beat and the other of interception of the blades (around 6/100 of second for the secondary mill and around the half for the tertiary mill), the inactive material, in gravitational free fall, it has to cover a run equal to the length of the blades in radial direction; this to allow the total filling of the themselves blades. In the case some piece of crushed stones, for uncontrollable circumstances, desultorily doesn't succeed in entering the invitations, (7), the blades (6), adequately proportionate as mass, will provide also to the breakup of the s device of interruption (joint) of the organ of transmission. Once intercepted by barycentric trajector positioned in the mo: toward the front of the hammer.

As it regards the mass in phase between the two rotors, it is proceeded as it follows. Once established opportunely the point of impact I , the necessary fraction of time is calculated for covering the run of the inert material, from the point of throwing L to that of impact I. In base to this time, common also to the principal rotor, the position of the hammer (3) is calculated during the throwing. At this stage will be affixed some notches of reference, so that the mass in phase can be restored in every moment, particularly in case of automatic driving of the device of interruption (joint) of the organ of toothed transmission (11), in case of irregular block of the secondary rotor (5). Obviously, others will serve similar notches of reference to keep track of the reversibility of rotation of the machine in the case that the mill is realized reversing.

A last consideration is made on the particular form assumed by the rotating device of interception of the inert material in the case in which the mill is not realized reversing. The all represented in the constructive detail of which to the fig. 5 that, as order of greatness, is reported to the rotating device of interception of a tertiary mill, with the precise statement that everything how much it will be said, with the due proportions of sizing, it is also worth for that of a secondary mill. How to note from the fig. 5, if the rotation happens only in a sense, it is possible foresee the blades of interception (6') that can be dismantled, through the adoption of a blade holder fixed to the axle of rotation; in such way it is easier and economic, especially in the zones with material very abrasive, the replacment of the themselves blades, once wears out. Also in this case the reduced thickness of the free extremity of the blades is guaranteed, having the adroitness to realize a suitable inclination ( is more that sufficient a 50%) to the free extremity of the blade holder; such inclination is proportional to the speed of rotation of the bladess and the speed of gravitational free fall of the i of inert material that goes down in gravitational way to have a thickness the more reduced possible; the it is disposed accor reversibility of the n but the necessity of have an internal form with a perfectly constant bending, makes to opt for the most comfortable solution of the two invitations, easily realizable solution in the foundry, in only circular piece with superior admission port for the material entrance and inferior port for the exit; in this way the advantage of the reversibility of the invitations will also be had (all it takes is horizontally rotating of

180°), to exploit especially in those zones with inert materials a lot of abrasives. Always in the case in which the mill is realized not reversing, it is possible to apply a special corrector of throwing (11) to the inferior extremity of the invitation, to avoid that some grain of inert material escapes to the impact through the superior part of the hammer.

Other advantage offered by the non reversing mill is the fact that the hammers, not working on both the front, can be realized tapered (preferred form also structurally), with consequent economic advantage that derives of it.

Claims

1) Mill to two or more constituted by a hoppt contains a principal π usury (2), the hammers (3), the armour (4), a secondary rotor (5') and relative peripheral orbit (5), characterized by the fact that: the relationship between the diameter of the peripheral (1 ') principal inferior greater and that of the peripheral smaller superior (5'), of the two rotors, the principal (1) and the secondary (5), it is variable, according to the dimensions of the inert material to be treated, from 1,5 to 2 about for the secondary mills and from 4 to 7 about for the tertiary mills; the peripheral circumferences (1') and (5') of the two rotors (1) and (5) they are placed, one in comparison to the other, a lot of near (around 2-3 centimeters); joing secondary rotor is endowed with blades in equal number to that of the hammers of the principal rotor and one or two lateral invitations curvilinear (7), with the superior edges inside beveled (7') and tangentially joined to the peripheral (5'); it has lack of the registers of approach of the armored walls to the hammers; the hammers are set to a notable distance by the armored walls (least 4 centimeters); the protections anti usury (2) have a width equal to the inside width of the mill.

2) Mill to two or more hammers, secondary and tertiary, according to the claims 1), characterized by the fact that with the apposition of opportune notches of reference, for the restoration in every moment of the mass in phase of the two rotors, the principal (1) and the secondary (5), it is possible obtain the reversibility of rotation of the machine.

3) Mill to two or more hammers, secondary and tertiary, according to the claims 1), characterized by the fact that the secondary rotor (5) is endowed with blades (6) with linear taper along their longitudinal development, with reduced dimension of heading, so that doesn't interfere with the flow of inert material that comes from the hopper 4) Mill to two or according to the claim 1), characterized by the fact that the blades (6'), of form and rectangular section, ca rotation; such blades h< inclination.

5) Mill to two or more hammers, secondary and tertiary, of the non reversing type, according to the claim 1) and 4), characterized by the fact that to the inferior extremity of one of the two invitations (7) a device (11) is applied with the function of addressing of the inert materials on the front of the hammers. 6) Mill to two or more hammers, secondary and tertiary, of the non reversing type, according to the claim 1), 4) and 5) characterized by the fact that the hammers (3') are realized tapered (one of the front are inclined in comparison to the other).

7) Mill to two or more hammers, secondary and tertiary, according to one or more preceding claims, characterized by the fact that the inert material, coming from the high (from the hopper of load), is intercepted by the blades (6), or from the blades (6') in the case of non reversing mill, of the secondary rotor (5), that invite it to great speed second to a circular trajectory and instantly launch it from the barycentric point L, in tangential direction, against the front of the hammer, creating, in such way, a component of the speed of throwing that is gone to add to the peripheral speed of the hammer, increasing, so, the speed of impact (in the tertiary mills, such speed can overcome the 90 m/s).

8) Mill to two or more hammers, secondary and tertiary, according to the preceding claims, characterized by the fact that it is possible to exploit the aforesaid component of the speed of throwing not to increase the speed of impact, that stays unchanged, but to decrease the peripheral speeds of the principal rotor (1) and of the secondary (5), or the number of the turns of the themselves rotors (above all for the secondary mill that can almost halve) for an easier interception of the inert material from the blades (6) or (6') in the case of the non reversing mill.

9) Mill to two or more hammers, secondary and tertiary, according to the preceding claims, characterized by the fact that the flow of feeding of the inert material in the hopper (10) is maintained adherent to the opposite wall to that in which the window of load is present (9 ^• known types; more specifically, if the flow of inert goes down adherent to the left wall of the hopper, the the flow of inert goes rotation of the blades ii with the blades.

10) Mill to two or more hammers, secondary and tertiary, according to the preceding claims, characterized by the leaving of the armored walls (4) from the hammers to avoid the breakup of the inert material to crushing, so that the making of the inert materials it totally happens to impact (break tensions of type normal, instead of tangential).

11) Mill to two or more hammers, secondary and tertiary, according to the preceding claims, characterized by the fact that thanks to the throwing of the inert material against the front of the hammers (3) or (3') and thanks to the short distance between the two peripherals (1') and (5'), comes to be optimized the phase of throwing and impact (reduction of the effects uncontrollable and great precision in the attainment of the point of impact).