EP3585518A1

EP3585518A1 - Cone crushing machine and crushing method using such a machine

Info

Publication number: EP3585518A1
Application number: EP18709673.0A
Authority: EP
Inventors: Jérôme PORTAL
Original assignee: Fives FCB SA; Fives Solios SA
Current assignee: Fives FCB SA; Fives Solios SA
Priority date: 2017-02-27
Filing date: 2018-02-20
Publication date: 2020-01-01
Anticipated expiration: 2038-02-20
Also published as: JP2020508218A; FR3063234B1; US20200023372A1; US11369969B2; KR102470398B1; KR20190116317A; CN110446554B; CA3052731C; JP6976355B2; CA3052731A1; DK3585518T3; ZA201904890B; AU2018225355A1; AU2018225355B2; CN208679263U; EP3585518B1; WO2018154222A1; FR3063234A1; RU2741635C1; CN110446554A

Abstract

A crushing machine (1) comprising: a frame (2), a vessel (3), a cone (5) positioned inside the vessel (3), the machine (1) further comprising a device (7) for vibrating the vessel (3) relative to the frame (2); the machine (1) being characterised in that the device (7) for vibrating the vessel (3) comprises at least two vibrators (8a, 8b, 8c, 8d) mounted on the chassis (4), each vibrator (8a, 8b, 8c, 8d) being rotated about a longitudinal axis of the chassis by a motor (10), each motor (10) driving the vibrator with which it is associated separately from the others.

Description

Cone crushing machine and grinding process involving such machine

The invention relates to the field of fragmentation machines, also called crushing and / or crushing machines, such as ores. More specifically, the invention relates to the field of grinding machines in which the material is ground between a cone and a truncated bottomless tank by setting the vessel in motion relative to the cone.

The operating principle of such a machine is described in document FR 2 687 080. The machine comprises a conical head, also called the cone, housed in a vessel, a space being defined between the head and the vessel. The conical head is in a fixed position relative to a frame, while the tank is positioned on a supporting structure, mounted floating relative to the frame. The supporting structure is movable in a horizontal plane relative to the frame by means of vibrators which are set in motion by appropriate means. Thus, the material discharged into the space between the cone and the tank is milled by the setting in motion in circular translation in the horizontal plane of the tank relative to the cone. The milled material then falls into a conduit located under the cone.

EP 0 642 387 proposes two improvements. On the one hand, the conical head is mounted free to rotate about a vertical axis relative to the frame, in order to limit the phenomena of wear due to movements in a tangential plane between the tank and the head. On the other hand, the height of the cone relative to the tank can be adjusted, so as to adjust the minimum width of the space between the head and the tank, and therefore the maximum size of the crushed products. Indeed, by measuring the speed of rotation of the head, and knowing the maximum width of the grinding space, it is deduced the thickness of the material layer, and therefore the maximum size of the crushed products. By comparing this thickness with a setpoint, it is possible to adjust the parameters of the machine. EP 0 833 692 discloses a system for vibrating the vessel to limit vertical vibrations. For this purpose, several shafts with vertical vibrator are mounted on a frame supporting the tank, each shaft carrying a vibrator composed of two weights arranged on either side of a base of the frame defining a horizontal plane. Thus, when the vibrators are rotated, the forces they exert are located in the horizontal plane of the base.

In the examples presented above, the vibrating system comprises vibrator shafts, generally four, arranged in a square around the tank and the conical head. A first vibrator shaft is coupled to a motor, and the other shafts are driven from the first shaft by a set of pulleys and belt. The rotation of the vibrators must be synchronized to avoid the appearance of parasitic moments.

When starting the machine, the shafts with vibrators are rotated, their speed gradually increasing to a nominal speed. The material discharged between the head and the tank is then crushed. However, without any particular precaution, the vibrations of the tank pass through different frequencies, some of which may correspond to the resonant frequencies of the machine, which is detrimental to the machine.

It is then known to set up a phase shift device for adjusting the angular offset of one group of vibrators with respect to the other group, in order to modify the amplitude of the resultant of the forces generated by the vibrators. Thus, at startup, two vibrators are in phase opposition with respect to the other two vibrators so that the resultant forces generated by the vibrators is zero: the vessel is stationary relative to the head. The phase opposition is maintained until the nominal speed is reached. Then, all vibrators are phased, so that the resultant forces are maximum, and the tank is set in motion relative to the head to grind the material.

For example, as shown in EP 0 833 692, the amplitude can be modified by means of one or two rotary jacks allowing to modify the phase shift of the vibrators of a group compared to those of the other group.

Thus, the phase shift and the phasing of the vibrators relative to each other rely in particular on the transmission by the set of pulleys and belts, making the adjustment unclear and unreliable. In fact, the wear of the pulleys and belts as well as the tension in the belts must be monitored in order to maintain a fine adjustment. The belt can also "jump" on the notches of the pulleys, especially since the notches are subject to wear, shifting the angular position of the vibrators relative to each other.

In addition, the set of pulleys and belts increases the number of parts on the machine, making it more complex and making maintenance difficult. In particular, the hydraulic cylinders for rotating the shafts of the vibrators require a robust seal, both vis-à-vis the pivoting shafts, but also vis-à-vis the vibrations of the machine. Many leakage problems can occur.

In addition, during the operation of the machine, the hydraulic cylinders tend to rotate, especially because of leaks that can be accentuated under the effect of the vibrations of the machine, so that their position becomes random. Hydraulic cylinders can not reliably hold an intermediate position. Thus, the vibrators generally operate on an all-or-nothing principle: either the vibrators are out of phase, and the resultant of the forces is zero, or the vibrators are in phase, and the resultant is maximum. An intermediate position can only be held for a short time, exceptionally.

However, it may be necessary to adjust the value of the maximum resultant as a general process setting. Since this value can not be permanently adjusted by holding the jacks in an intermediate position, mechanical stops are manually installed in the jacks to define a position giving the maximum resultant. The implementation of the stops is tedious, and involves stopping the grinding machine the time of installation operations. However, the grinding machine being in General integrated into a more comprehensive process of processing the material, stopping the machine impacts the overall process.

There is therefore a need for a new grinding and / or crushing machine overcoming in particular the aforementioned drawbacks.

For this purpose, according to a first aspect, the invention proposes a grinding machine comprising:

a frame,

a tank forming internal grinding track. The tank is mounted on a frame movable in translation at least in a plane transverse to the frame,

a cone forming an outer grinding track and placed inside the tank.

The machine further comprises a device for vibrating the vessel relative to the frame in a transverse plane, so that material is ground between the inner track and the outer grinding track by the relative movement of the vessel relative to at the cone.

The device for vibrating the vessel comprises at least two vibrators mounted on the frame, each vibrator being rotated about a longitudinal axis of the chassis by a motor. Each motor drives independently of each other the vibrator with which it is associated. The device for vibrating the vessel further comprises a motor control system and a system for measuring the relative phase angle between the vibrators, so that the vibrating device can take at least three positions:

a so-called zero position, in which the phase shift angle between the vibrators is such that the vibrations of the tank are of minimum amplitude; a so-called maximum position, in which the phase shift angle between the vibrators is zero, so that the vibrations of the vessel are of maximum amplitude;

at least one so-called intermediate position, in which the phase shift angle between the vibrators is such that the vibrations of the vessel are of intermediate amplitude between the maximum amplitude and the minimum amplitude, the control system being adapted to move the vibration device from one position to another while maintaining the rotation of the vibrators.

Vibrations for crushing the material can thus be adapted in line, without stopping the machine, depending on the grinding power required to grind the material. The machine thus works continuously.

According to one embodiment, each motor is mounted on the frame and comprises a motor shaft extending longitudinally. Each vibrator is mounted on a vibrator shaft, a connection between the motor shaft and the corresponding vibrator shaft comprising a rigid coupling in the transverse plane, so that the vibrator shaft is rotated by the motor shaft and a flexible coupling in the longitudinal direction, so that the vibrator shaft is movable in the longitudinal direction relative to the motor shaft on a determined maximum stroke.

The flexibility of connection between the motor shaft and the vibrator shaft preserves the machine while ensuring efficient transmission.

For example, the connection between the motor shaft and the vibrator shaft may comprise a connecting rod having a homokinetic transmission joint between the motor shaft and the vibrator shaft, and may also comprise an intermediate piece between the connecting rod and the vibrator shaft. 'engine shaft. The intermediate piece may comprise a strip of elastomeric material mounted astride between two parts of a rigid body of the intermediate piece. More specifically, a first portion may be attached to one end of the drive shaft and a second portion may be attached to one end of the link. One of the first portion and the second portion may further comprise a longitudinal protruding lug cooperating with a longitudinal bore of the other of the first portion and the second portion to guide the movement of the vibrator shaft according to the longitudinal direction relative to the motor shaft.

This embodiment is inexpensive to set up and ensures the transmission between the motor shaft and the vibrator shaft effectively.

According to one embodiment, each motor comprises a motor mode, in which the motor consumes energy to rotate the associated vibrator, and a generator mode, in which the motor generates energy by braking the associated vibrator. For this purpose, for example, the engine control system may include a device for recovering and storing at least a portion of the energy generated by each engine in generator mode. Alternatively or in combination, the engine control system may include a device for dissipating at least a portion of the energy generated by each engine in generator mode.

The recovered energy thus makes it possible to reduce the operating costs of the machine. The recovered energy can thus be used either to control the machine or to feed other devices.

According to a second aspect, it is proposed a grinding process using a grinding machine as presented above. The method then comprises the following steps:

setting the vibration device to zero;

the determination by the control system of a grinding force according to at least one grinding parameter;

increasing the speed of rotation of the vibrators to a value determined by the grinding force;

placing in the relative position of the vibrators with a phase shift angle between the vibrators determined by the grinding force;

- Feed material to grind the machine between the two grinding tracks.

The method further comprises, the rotation of the vibrators being maintained:

detecting a change of at least one grinding parameter; the determination of a new grinding force;

changing at least the phase angle between the vibrators according to the new effort.

According to a particular embodiment, a modified grinding parameter may be the particle size of the crushed material at the outlet of the grinding machine. Thus, by adjusting the in-line grinding force, the grain size characteristics of the output material of the machine can be adapted as needed. Alternatively or in combination, a modified milling parameter may be the particle size of the material feeding the milling machine. Changing the particle size of the material entering the grinding machine is common. It is thus particularly advantageous economically to adapt the grinding force to the particle size of the material to be ground.

According to one embodiment, the grinding machine further comprises a vibration sensor of the vessel in the longitudinal direction, that is to say the vertical vibrations. The detection of a modification of the grinding parameter can then comprise:

the determination of a reference spectrum of the longitudinal vibrations of the tank,

the comparison between the reference spectrum and a spectrum measured by the vibration sensor,

the quantification of a difference between the reference spectrum and the measured spectrum

if the quantized difference exceeds a threshold value, the confirmation of the detection of a modification of at least one grinding parameter of the material feeding the grinding machine.

The monitoring of vertical vibrations makes it possible in particular to monitor a machine failure, and to anticipate it to avoid breakage which would require a long stop of the machine for repair.

According to one embodiment, the setting in starting position comprises the following steps:

the vibrators being at a standstill, the recording of an initial position of the vibrators in which the phase difference between the vibrators corresponds to the zero position of the vibrating device;

moving the vibrators;

rotating the vibrators until the vibrators are in their initial position.

This procedure for registering an initial position allows you to start the machine faster and automatically. By for example, when a failure has required stopping the machine, restarting the machine from the registered initial position can be done automatically.

According to one embodiment, when a material supply cutoff occurs, the device for vibrating the tank is placed in the zero position, in order to preserve the machine. As each vibrator is controlled independently of the others by a motor, the setting in zero position is done very quickly, preserving the integrity of the machine.

According to one embodiment, when a power failure of the motors occurs, the method may comprise the following steps:

the generator mode of at least one engine,

recovering and storing at least a portion of the braking energy by the recovery and storage device;

the setting in zero position of the device for vibrating the tank by using at least a portion of the energy recovered in the recovery and storage device for phase shifting the vibrators,

maintaining the zero position until the rotation of all the vibrators stops.

Other effects and advantages will become apparent in the light of the description of embodiments of the invention accompanied by the figures in which: FIG. 1 is a sectional view from above of a grinding machine according to an embodiment of the invention. in which four vibrators are controlled by four independent motors;

- Figure 2 is a view of the machine of Figure 1 along the section line II-II;

Figure 3 is a schematic representation of an embodiment of the control of the machine of Figure 1;

Figure 4 is a detail view IV-IV of Figure 2.

In Figures 1 and 2, there is shown a machine 1 of vibration grinding. The machine 1 comprises in particular a frame 2, intended to rest on the ground. The machine 1 further comprises a tank 3, the inner surface of which forms an inner grinding track 3a. The tank 3 is mounted on a frame 4 movable in translation relative to the frame 2 at least in a transverse plane, which is in practice substantially the horizontal plane. For this purpose, the frame 4 is mounted on the frame 2 by means of elastic studs 4a, elastically deforming both transversely and longitudinally to limit the transmission of vibrations to the frame 2. A cone 5, the outer surface of which is form substantially complementary to that of the inner surface of the vessel 3 and which forms an outer grinding track 5a is placed inside the vessel 3. Preferably, the cone 5 is mounted on a shaft 6 extending in a manner. A longitudinal axis, which is in practice substantially vertical, and supported by a secondary frame 2a. The secondary frame 2a is suspended from the frame 4.

The machine 1 finally comprises a device 7 for vibrating the vessel 3 relative to the frame 2 in a transverse plane (Figure 3). Thus, under the effect of the vibrating device 7, the vessel 3 moves in a transverse plane with respect to the cone 5, so that material is ground between the inner station 3a and the outer track 5a. The vibrating device 7 comprises at least two vibrators.

According to one embodiment which is that of the figures, the vibrating device 7 comprises four vibrators 8a, 8b, 8c, 8d distributed in square on the frame 4. Each vibrator 8a, 8b, 8c, 8d can be formed of two parts called weights distributed on both sides of a substantially transverse plane of the frame 4, so that the vibrations of the tank 3 caused by the rotation of the vibrators 8a, 8b 8c, 8d remain substantially in this transverse plane. Each vibrator 8a, 8b, 8c, 8d is fixed on a shaft 9a, 9b, 9c, 9d vibrator of longitudinal axis driven in rotation with respect to the frame 4 by a motor 10, the motors 10 of the shafts 9a, 9b to Vibrator are visible in Figure 2. Thus, when the vibrators are rotated, the vessel 3 is vibrated and describes a circular translational movement in a transverse plane. In general, the vibrating device 7 comprises at least two vibrators, distributed regularly around the longitudinal axis A, in order to generate vibrations, mainly or exclusively, in the transverse plane, so that the energy consumed by the The machine is optimally used to grind the material between the inner track 4a and the outer grinding track 5a. Special measures can be taken to limit longitudinal vibrations, that is to say in practice vertical vibrations. The vibrators are for example identical to each other, and arranged equidistant from the longitudinal axis A and equidistant from each other. When the vibrators are not identical, the distance to the longitudinal axis A and the distance between them can be adapted accordingly.

Each motor 10 drives the corresponding vibrator independently of the other vibrators. More precisely, each motor 10 controls the position and the rotational speed of the corresponding vibrator. As will be explained below, each motor 10 is preferably a reversible motor, that is to say it comprises a motor mode, in which it consumes energy to rotate the corresponding vibrator, and a generator mode in which it generates energy by braking the corresponding vibrator.

More specifically, the vibrating device 7 comprises a system 11 for controlling the motors 10 and a system 12 for measuring the relative phase shift between the vibrators 8a, 8b, 8c, 8d, ie the relative angle between the vibrators 8a, 8b, 8c, 8d, so that the vibration device 7 can take at least three positions:

a so-called zero position, in which the phase shift angle between the vibrators 8a, 8b, 8c, 8d is such that the vibrations of the tank 3 are of minimum amplitude, or even zero;

a so-called maximum position, in which the phase shift angle between the vibrators 8a, 8b, 8c, 8d is zero, so that the vibrations of the tank 3 are of maximum amplitude; at least one so-called intermediate position, in which the phase shift angle between the vibrators 8a, 8b, 8c, 8d is such that the vibrations of the vessel 3 are of intermediate amplitude between the maximum amplitude and the minimum amplitude.

In practice, the vibration device 7 can take a multitude of intermediate positions, so as to adjust the amplitude of the vibrations according to the required grinding power.

According to the example shown in the figures, that is to say with four vibrators 8a, 8b, 8c, 8d, the phase shift of the vibrators is made in pairs. Thus, in the zero position, the diagonally opposed vibrators 8a, 8c are in phase with each other, as are the diagonally opposite vibrator 8b, 8d in phase with each other, while the vibrators 8a, 8c are in phase opposition with respect to the vibrators 8b, 8d, that is to say that the phase angle is substantially 180 °. In the maximum position, the four vibrators 8a, 8b, 8c, 8d are in phase with each other. Finally, in the intermediate position, the vibrators 8a, 8c are out of phase by an angle different from 180 ° with respect to the vibrators 8b, 8d.

More specifically, each vibrator 8a, 8b, 8c, 8d can be associated with a position sensor, to know at each moment the position of each of the vibrators 8a, 8b, 8c, 8d.

The control system 11 is thus able to move the vibrating device 7 from one position to the other while maintaining the rotation of the vibrators. Indeed, thanks in particular to the independence of the motors 10, at any time, the position of each vibrator, its rotational speed and its phase shift relative to the other vibrators are known and can be regulated online, without the machine 1 must be stopped.

For this purpose, the control system 11 comprises a computer 13 which, from the knowledge of the rotational speed and the position of each vibrator and the phase shift between the vibrators 8a, 8b, 8c, 8d allows to know at at any time the amplitude of the vibrations of the vessel 3. By comparing the calculated value with a target value, the vibrating device 7 can regulate in particular the phase difference between the vibrators 8a, 8b, 8c, 8d to regulate the vibration amplitude of the vessel 3 at any time, and thus regulate the grinding force. Optionally, the control system 11 can further regulate the speed of rotation of the vibrators to regulate the grinding power.

Thus, the intermediate position does not depend on the mechanical assembly, but can be adjusted online, without stopping the operation of the machine 1, by the system 11 for controlling the motors 10 acting directly on the motors. In addition, thanks to the use of motors 10 each associated with a vibrator 8a, 8b, 8c, 8d, the position of each vibrator 8a, 8b, 8c, 8d is held with great reliability over a period of time of a few minutes at several hours. For example, the control system 11 makes it possible to connect the motors 10 via a load sharing system, to ensure synchronized control of the motors 10 and the vibrators 8a, 8b, 8c, 8d.

With this new milling machine 1 design in which the vibrators 8a, 8b, 8c, 8d are each controlled by a motor 10 independently of each other, the machine 1 can adapt the grinding force according to the characteristics the incoming material and the characteristics referred to for the material leaving the machine 1.

Thus, to grind the material, the vibrating device 7 is previously placed in the zero position. An initial grinding power can be determined by the computer 13 as a function of at least one grinding parameter. The initial grinding power determines an initial rotational speed and an initial phase shift of the vibrators 8a, 8b, 8c, 8d, this initial phase shift being able to correspond to the maximum position then to an intermediate position. The control system 11 then progressively increases the speed of rotation of the vibrators 8a, 8b, 8c, 8d until it reaches the initial value. Since the vibrating device 7 is in the zero position, the tank 3 has no or only a few transverse displacements with respect to the cone 5. Thus, during the rise in rotational speed, it is possible to pass through resonance of the machine 1 that could degrade it. Then, the Control system 11 moves the vibrators so as to obtain the determined initial phase shift, and thus the initial grinding power.

As long as the grinding parameters are not modified, the grinding power can be maintained substantially equal to the initial grinding power: the speed of rotation of the vibrators and the phase shift are maintained, with increased reliability thanks to the use of the motors 10 each associated with a vibrator 8a, 8b, 8c, 8d.

However, it may happen that a grinding parameter is changed during feeding of the material.

By grinding parameter, here means any parameter that can affect the characteristics of the material at the output of milling machine 1. The granulometry of the granules, that is to say, in particular the size, the hardness, the shape and the porosity of the granules, the density of the incoming material, the granulometry targeted by the granules at the outlet of the granule, may be mentioned in a nonlimiting manner. matter, the material flow. In practice, the granulometry of the incoming material, and in particular the size of the granules, with respect to the particle size, and in particular the size of the granules, of the outgoing material constitute the grinding parameters most often used.

By detecting the modification of a grinding parameter, a new grinding power can be calculated by the computer 13, and the phase shift angle, and / or the speed of rotation, of the vibrators can be modified to obtain the new power of grinding, while maintaining the rotation of the vibrators. Again, the phase angle of the vibrators may correspond to the maximum position or an intermediate position.

Indeed, the grinding power is directly related to the amplitude of the vibrations of the vessel 3, which is determined by the phase difference between the vibrators. More precisely, it is the grinding force that depends directly on the phase shift of the vibrators.

However, the required grinding power can be determined in particular according to the characteristics of the incoming material and the characteristics targeted for the outgoing material. For example, the larger the difference in size between the granules of the outgoing material and the incoming material is important, the greater the grinding power must be important.

An example of application relates to mineralurgy, that is to say the grinding of ores. Depending on the needs, it may be that the outgoing material has a proportion of pellets of sizes smaller than a required size, called fines, which is too high. Indeed, fine particles can be detrimental to downstream processing processes. Thanks to the new machine 1 presented here, the grinding power is adjusted to avoid the production of fines.

Generally, thanks to the grinding machine 1 thus designed, and unlike the machines of the state of the art, it is not necessary to stop the milling machine 1 to change the phase difference between the vibrators 8a, 8b , 8c, 8d and maintain a new grinding power different from that initially determined when starting the machine 1.

The modification of a grinding parameter can be done upstream of the machine 1, for example by directly measuring the characteristics of the incoming material, or downstream of the machine 1, for example by measuring the characteristics of the outgoing material. According to one embodiment, the machine 1 further comprises a sensor for longitudinal vibrations of the vessel 3. Comparing the spectrum of the longitudinal vibrations measured by the sensor with a reference spectrum, it is possible to detect a modification of a parameter grinding. A difference between the measured spectrum and the reference spectrum is quantified. It may be for example a difference in amplitude, frequency or a time shift. If the quantized difference exceeds a threshold value, the detection of a modification of a grinding parameter can be confirmed, for example by sending a signal to the vibrating device 7, so as to regulate the phase shift of the vibrators.

Indeed, there may be situations in which the grinding power of the machine 1 is unsuitable. For example, the power may be insufficient, so that the granules of the incoming material are not crushed, and cause a blockage. It can also happen that the power grinding is too high, so that the outer track 5a of the cone 5 comes into contact with the inner track 3a of the tank 3. In such situations, undesired longitudinal vibrations appear, indicating that the grinding power must be adjusted .

The machine 1 thus formed may be more reactive to changes in grinding parameters than grinding machines of the state of the art. In particular, when a cut of material feed occurs, it is quickly detected, and, thanks to the motors 10, the device 7 for vibrating can quickly go into zero position, to prevent the tank 3 from coming in contact with the cone 5 and that the grinding tracks 3a, 5a are degraded. The reaction time is of the order of a few seconds between the detection of the material supply cutoff and the zero position setting, while in the state of the pulley technique, the reaction time is several tens of hours. seconds.

The position of the vibrators is also accurate, with generally an angular offset of less than 1 °. In addition, the position and speed of the vibrators 8a, 8b, 8c, 8d being known at all times, it is easy to set up a predictive maintenance: when the power developed by a vibrator deviates too much from a power of reference or that of the other vibrators, a maintenance signal can be generated to indicate that an intervention, for example a greasing operation, a diagnosis of the bearings or a visual inspection, must be carried out.

According to an embodiment illustrated in particular in FIG. 4, the position sensor of each vibrator is of coder type. An operator places the vibrators 8a, 8b, 8c, 8d in an initial position in which the phase difference between the vibrators 8a, 8b, 8c, 8d corresponds to the zero position of the vibrating device 7. Each encoder then records the position of the associated vibrator. Thus, after the vibrators 8a, 8b, 8c, 8d have been moved away from their initial position, to start the machine 1 it is necessary to bring the vibration device 7 back to the zero position, in order to be able to increase the speed up to the speed determined by the required grinding power without generating vibrations. For this purpose, the motors 10 rotate the vibrators 8a, 8b, 8c, 8d until each vibrator 8a, 8b, 8c, 8d is returned to the initial position, before increasing their rotational speed. Thus, the machine 1 can be stopped abruptly, the vibrators 8a, 8b, 8c, 8d being in a position with any relative phase shift; the restart of the machine 1 is always done with the vibration device 7 in the zero position.

As mentioned above, the motors 10 may be reversible type. Thus, according to one embodiment, the engine control system 11 comprises a device 14 for recovering at least a portion of the energy generated by each engine 10 in generator mode. Thus, when a power failure occurs, at least one motor 10, in practice all the motors 10, go into generator mode. The recovered energy can then be used by the control system 10 to put the vibrating device 7 in the zero position, so that the vibrations of the tank 3 are almost zero. Thus, the speed of rotation of the vibrators 8a, 8b, 8c, 8d gradually decreases, the vibrating device 7 being maintained in zero position, without passing through the resonant frequencies of the machine 1 which could degrade it.

According to one embodiment, the energy recovered by the recovery device 14 can be stored.

According to another embodiment, the energy recovered by the recovery device 14 is directly used by one or more motors 10. More specifically, during the transient phases comprising in particular the phase shift changes between the vibrators 8a, 8b, 8c, 8d. since the motors 10 are connected to a charge-sharing system, the electrical energy generated by the motor (s) which switch to generator mode can then be directly transmitted to the motor (s) in drive mode. The sharing system thus makes it possible to distribute power between the motors 10 during transient phases involving very large power differences between the motors 10.

Optionally, the control system 11 may further comprise a device 15 for dissipating at least a portion of the energy generated by each engine in generator mode, to evacuate excess energy and avoiding an overload on the load sharing system in case of example fast braking.

According to one embodiment, each motor 10 is mounted on the frame 2 and comprises a motor shaft 16, extending longitudinally, and connected to the shaft 9a, 9b, 9c, 9d with corresponding vibrator using a link 17 for driving the shaft 9a, 9b, 9c, 9d rotating vibrator. For this purpose, each shaft 9a, 9b, 9c, 9d with vibrator being mounted in rotation about an axis parallel to the longitudinal axis of the frame 4, the link 17 between the motor shaft 16 and the shaft 9a, 9b , 9c, 9d corresponding vibrator comprises a rigid coupling in the transverse plane. However, any longitudinal vibrations of the frame 4 carrying the tank 3 can degrade the connection between the shafts. To avoid this, the connection further comprises a flexible coupling in the longitudinal direction, so that the shaft 9a, 9b, 9c, 9d vibrator can move in the longitudinal direction relative to the motor shaft 16 on a race determined maximum. This arrangement also makes it possible to arrange each motor 10 substantially in the longitudinal alignment of one of the vibrators 8a, 8b, 8c, 8d.

For example, the link 17 between the motor shaft 16 and the shaft 9a, 9b, 9c, 9d with corresponding vibrator comprises a connecting rod 18 with homokinetic transmission joint. This is for example a connecting rod 18 double universal joint. The link 17 further comprises an intermediate piece 19 between one end of the connecting rod 18, for example the motor end end 10. This intermediate piece 19 is formed in particular of a rigid body, for example a metal body, in two parts 20a, 20b, and a band 21 of elastomeric material straddling between the two parts 20a, 20b of the rigid body 20. More specifically, the band 21 is of annular shape, each of its free edges being rigidly fixed to one of the parts 20a, 20b of the rigid body 20. A first portion 20a of the rigid body 20 is rigidly attached to one end of the motor shaft, and the second portion 20b is attached to the motor end 10 of the connecting rod 18. The elastomeric band 21 is sufficiently elastic to deform longitudinally, allowing a relative longitudinal movement on a determined stroke between the motor shaft and the shaft 9a, 9b, 9c, 9d corresponding vibrator. In order to guide this longitudinal displacement, one of the two parts, for example the first part 20a, comprises a lug 22 projecting longitudinally, and the other part, for example the second part 20b, comprises a longitudinal bore 23, complementary to the lug 22, to allow the sliding with guiding the lug 22 in the bore 23. The lug 22 may be attached by rigid attachment to the first portion 20a, or be integral with the first portion 20a. The second part 20b is for example made of steel, and a self-lubricated bronze ring is force-fitted into the bore 23.

The link 17 thus allows flexibility in the transmission of rotation from the shafts 16 to the shafts 9a, 9b, 9c, 9d vibrator absorbing the vibrations of the vessel 3 relative to the frame 2. The cooperation between the pin 22 and the hole 23 makes it possible to avoid transverse movements that are detrimental to the mechanical strength of the connection 17.

Claims

Grinding machine (1) comprising:

- a frame (2),

a vat (3) forming an inner grinding track (3a), the vat being mounted on a frame (4) movable in translation at least in a plane transverse to the frame,

a cone (5) forming an outer grinding track (5a) and placed inside the tank (3),

the machine (1) further comprising a device (7) for vibrating the vessel (3) relative to the frame (2) in a transverse plane, so that material is ground between the inner track (3a) and the external grinding track (5a) by the relative movement of the vessel (3) with respect to the cone (5); the machine (1) being characterized in that the device (7) for vibrating the tank (3) comprises at least two vibrators (8a, 8b, 8c, 8d) mounted on the frame (4), each vibrator ( 8a, 8b, 8c, 8d) being rotated about a longitudinal axis of the frame by a motor (10), each motor (10) driving independently of each other the vibrator with which it is associated, the device (7) for vibrating the vessel (3) further comprising a motor control system (11) (10) and a system (12) for measuring the relative phase shift angle between the vibrators (8a, 8b, 8c, 8d), so that the vibration device (7) can take at least three positions:

a so-called zero position, in which the angle of phase difference between the vibrators (8a, 8b, 8c, 8d) is such that the vibrations of the tank (3) are of minimum amplitude;

a so-called maximum position, in which the phase shift angle between the vibrators (8a, 8b, 8c, 8d) is zero, so that the vibrations of the tank (3) are of maximum amplitude;

at least one so-called intermediate position, in which the phase shift angle between the vibrators (8a, 8b, 8c, 8d) is such that the vibrations of the tank are of intermediate amplitude between the maximum amplitude and the minimum amplitude,

the control system (11) being able to move the vibration device from one position to the other while maintaining the rotation of the vibrators (8a, 8b, 8c, 8d).

2. Machine (1) according to claim 1, wherein each motor (10) is mounted on the frame (2) and comprises a shaft (16) extending longitudinally motor, and wherein each vibrator (8a, 8b, 8c , 8d) is mounted on a vibrator shaft (9a, 9b, 9c, 9d), a link (17) between the motor shaft (16) and the corresponding vibrator shaft (9a, 9b, 9c, 9d) comprising a rigid coupling in the transverse plane, so that the shaft (9a, 9b, 9c, 9d) vibrator is rotated by the shaft (16) motor and a flexible coupling in the longitudinal direction, so that the Vibrating shaft (9a, 9b, 9c, 9d) can move in the longitudinal direction relative to the motor shaft (16) over a determined maximum stroke.

3. Machine (1) according to claim 2 wherein the connection (17) between the shaft (16) motor and the shaft (9a, 9b, 9c, 9d) vibrator comprises a rod (18) having a seal homokinetic transmission between the motor shaft (16) and the vibrator shaft (9a, 9b, 9c, 9d), and comprises a piece (19) intermediate between the connecting rod (18) and the motor shaft (16), the intermediate piece (19) comprising a strip (21) of elastomeric material mounted astride between two parts (20a, 20b) of a rigid body (20) of the intermediate piece (19), a first part (20a) being fixed to one end of the motor shaft (16) and a second portion (20b) being attached to one end of the connecting rod (18), one of the first portion (20a) and the second portion (20b) further comprising a lug (22) projecting longitudinally cooperating with a bore (23) longitudinal of the other of the first portion (20a) and the second portion (20b) to guide the movement of the arbr e (9a, 9b, 9c, 9d) vibrator in the longitudinal direction relative to the shaft (16) motor.

Machine (1) according to any one of the preceding claims wherein each motor (10) comprises a motor mode, wherein the motor (10) consumes energy to rotate the vibrator (8a, 8b, 8c , 8d) associated, and a generator mode, wherein the motor (10) generates energy by braking the associated vibrator (8a, 8b, 8c, 8d).

5. Machine (1) according to claim 4, wherein the system (11) for controlling engines comprises a device (14) for recovering at least a portion of the energy generated by each engine (10) in generator mode. .

Machine (1) according to claim 4 or claim 5, wherein the engine control system (11) comprises a device (15) for dissipating at least a portion of the energy generated by each engine (10). ) in generator mode.

7. Grinding process using a grinding machine (1) according to any one of the preceding claims, comprising:

setting the vibrating device (7) to zero;

the determination by the control system (11) of a grinding force as a function of at least one grinding parameter;

increasing the speed of rotation of the vibrators (8a, 8b, 8c, 8d) to a value determined by the grinding force;

placing in the relative position of the vibrators (8a, 8b, 8c, 8d) with a phase shift angle between the vibrators (8a, 8b, 8c, 8d) determined by the grinding force;

feeding material to be crushed from the machine (1) between the two grinding tracks (3a, 5a),

the method further comprising rotating the vibrators (8a, 8b, 8c, 8d) being maintained:

- Detecting a change of at least one grinding parameter; the determination of a new grinding force;

modifying at least the phase shift angle between the vibrators (8a, 8b, 8c, 8d) as a function of the new force.

8. The method of claim 7, wherein a modified milling parameter is the particle size of the milled material output of the milling machine (1).

9. The method of claim 7 or claim 8, wherein a modified milling parameter is the particle size of the material feeding the grinding machine (1).

The method of claim 9, wherein the grinding machine (1) further comprises a vessel vibration sensor (3) in the longitudinal direction, and wherein detecting a change in the grinding parameter comprises:

the determination of a reference spectrum of the longitudinal vibrations of the tank (3),

quantifying a difference between the reference spectrum and the measured spectrum

- If the quantized difference exceeds a threshold value, the confirmation of the detection of a change of at least one grinding parameter of the material feeding the grinding machine (1).

11. The method as claimed in the preceding claim, wherein the setting in starting position comprises:

the vibrators (8a, 8b, 8c, 8d) being at a standstill, the recording of an initial position of the vibrators in which the phase difference between the vibrators (8a, 8b, 8c, 8d) corresponds to the zero position of the device (7) vibrating;

moving the vibrators (8a, 8b, 8c, 8d);

rotating the vibrators (8a, 8b, 8c, 8d) until the vibrators (8a, 8b, 8c, 8d) are in their initial position.

12. A method according to any one of claims 7 to 11, when a material supply cutoff occurs, the device (7) for vibrating the tank (3) is put in the zero position.

A method according to any one of the preceding claims, wherein the machine (1) is according to any one of claims 4 to 6, and wherein when a power failure of the motors (10) occurs, He understands :

the generator mode of at least one motor (10),

recovering and storing at least a portion of the braking energy by the recovery device (14);

setting the device (7) for vibrating the vessel (3) to zero position by using at least a portion of the energy recovered in the recovery device (14) to phase shift the vibrators (8a, 8b, 8c, 8d), maintaining the zero position until the rotation of all the vibrators (8a, 8b, 8c, 8d) stops.