CN100534635C - Oscillation sieving machine and operation method thereof - Google Patents

Abstract

The invention relates to a vibrating sieve machine (3) with an out-of-balance drive (5), with drive frequency and drive force adjustable during operation. It is thus possible to match the drive of the vibrating sieve machine (3) in a short time to differing charge materials and to provide the vibrating sieve machine (3) with a control (2) which guarantees an optimal operation with changing basic conditions.

Description

Vibrating screening machine and operation method of vibrating screening machine

technical field

The present invention relates to vibratory screening machines, equipment comprising vibratory screening machines, uses of vibratory screening machines or equipment and methods of operating vibratory screening machines.

Background technique

Vibrating screens are used in the construction industry to sort sand or gravel on the principle of a "vibrating screen". In this case, the vibratory screening machine is designed with regard to the screen surface and the screening excitation in such a way that it provides the best results with regard to the screening capacity and the screening rate in a given feed material to be used preferentially. If the composition (recipe) of the feed material is changed, the plant capacity can be significantly reduced and less than best sieving results obtained. This is a problem in particular in the case of hot vibrating screens in asphalt plants, since different grit formulations have to be processed according to the required bitumen quality and because the screening machine is located directly outside the hot mineral container, short-term reprocessing takes place on the screening machine .

Contents of the invention

It is therefore an object of the present invention to provide a method for operating a vibratory screening machine and a vibratory screening machine which do not have or at least partly avoid the above-mentioned disadvantages of the prior art.

A first aspect of the invention relates to a vibratory screening machine with a single exciter or with multiple exciters (excitation axes), preferably with two automatically synchronizable exciters. The excitation force, the excitation frequency and/or the excitation angle are adjustable during operation of the machine, preferably independently of each other. The so-called excitation angle is to be understood in linearly excited vibrating screen machines as the inclination angle between the direction of the exciting force and the separation surface (screen surface). This parameter does not exist in the vibration screening machine with pure rotation excitation. The resulting advantage is that the amplitude, vibration frequency and projection distance of the vibrating screen or screen surface can be adjusted in a targeted manner within a wide range, so that the machine can be used for different feed materials and can also be equipped with a complete An automatic control device which continuously determines and evaluates the sieving results and corrects, if necessary, the excitation force, the excitation frequency, the excitation direction and/or the feed rate per unit time in order to ensure an optimum operation. Such a vibrating screening machine can also be constituted as an "intelligent" and automatically optimized vibrating screening machine, that is, by automatically changing one or more of the above-mentioned parameters during the operation of the machine, the impact of its screening results is determined and thus determined The best parameter situation for the corresponding feed material.

It is preferred here if the excitation force, the excitation frequency and/or the excitation direction are continuously adjustable, so that a particularly sensitive control intervention is possible.

In a preferred embodiment of the vibrating screening machine, the vibrating screening machine has at least one vibrator comprising two unbalanced weights with a common axis of rotation, whose angular position relative to one another can be changed during operation of the machine. In this way, the degree of unbalance of the exciter and thus the exciting force can preferably be adjusted between zero (two unbalanced weights exactly opposite each other) and a maximum value (two unbalanced weights arranged at the same circumferential position). It also has the advantage that the moment of inertia of rotation remains constant when the degree of unbalance changes.

In another preferred embodiment of the vibrating screening machine, the vibrating screening machine has at least one vibrator, which includes an unbalanced weight, the distance of the unbalanced weight from the center of gravity of the rotating shaft can be adjusted during operation of the machine. Vary in order to adjust the degree of unbalance and thus the excitation force, and preferably between zero (the center of gravity of the unbalanced weight coincides with the axis of rotation) and a maximum value (the largest possible distance between the axis of rotation and the center of gravity of the unbalanced weight) between adjustments.

In yet another preferred embodiment, the vibratory screening machine has at least two exciter devices or units, which each comprise at least two exciters, wherein the excitation angle of at least one, preferably all, of the exciter devices is adjustable. changed in order to be able to adjust the resulting total excitation force jointly produced by them.

It is advantageous in this respect that the change of the excitation angle of the at least one exciter device can be achieved by changing the phase of the exciters of the exciter device relative to each other and/or by the at least one exciter relative to the body. A change in position is achieved.

Wherein it is also preferred that the vibratory screening machine has a plurality, preferably exactly two, of exciter devices, which respectively comprise exactly two exciters, wherein the two exciters of the first exciter device are designed to operate on a common first synchronous rotation in a direction of rotation is synchronous or synchronizable, and the two exciters of the second exciter arrangement are synchronous or synchronizable for synchronous rotation in a common second direction of rotation opposite to the first direction of rotation of. At the same time, the individual vibrators of the first vibrator device and of the second vibrator device are synchronized or synchronizable with one another. Furthermore, the phases of the two exciters of the first exciter arrangement with respect to each other are changeable and the phases of the two exciters of the second exciter arrangement are changeable with respect to each other in order to vary the first and second exciter The corresponding excitation angles of the vibrator devices and thus the resulting total excitation force jointly produced by the two vibrator devices can be adjusted.

Such a vibrating screening machine, which achieves the change of the exciting force by phase shifting of a plurality of exciters among each other, has the advantage that simple and inexpensive exciters can be used and no rotation occurs when the exciting force is adjusted Any change in the moment of inertia is preferred.

In a further preferred embodiment of the vibrating screening machine, it has at least one vibrator comprising an unbalanced weight, the weight of which can be varied during operation of the machine in order to adjust the unbalance and thus the exciting force , wherein preferably the unbalanced weight is a container from which liquid can be supplied and/or drained during operation. For example, a bladder reservoir is suitable as a container which is connected to a fluid feed and, depending on its pressure, is more or less filled with fluid. In this way, the unbalance can be easily adjusted via a fluid pressure. The transfer of liquid media such as hydraulic oil or water from a non-rotating component (machine body) to a rotating component (vibrating screen machine) is familiar to those skilled in the art and will therefore not be described in detail here.

In a further preferred embodiment, the vibratory screening machine has at least two vibrator exciters whose phase relative to one another can be changed during operation of the machine in order to adjust the excitation angle.

How the synchronization and phase shifting of the individual oscillators can be achieved is known to those skilled in the field of transmission technology and will therefore not be described in detail here. However, it should be pointed out that essentially both mechanical and electrical mandatory connections of the individual vibrators are provided.

If the vibratory screening machine has at least two exciters, it is preferred that the position of at least one exciter, and in particular all of the exciters, is changeable in operation relative to the body in order to adjust the position of all the exciters. The excitation angle and thus adjust the projection distance of the screen surface combined with the excitation force or amplitude. This is particularly advantageous in the case of two automatically synchronizable vibrators.

Preferably, the vibrating screening machine is equipped with a machine control device, in which the excitation frequency, excitation force or unbalance, excitation angle and/or feed quantity per unit time can be stored for different feed materials and can be stored in a machine control device. It can be retrieved again at a later time for the operation of the vibratory screening machine with such a feed material, and the vibratory screening machine can in particular be adjusted automatically for an operation with stored values via the machine control. The optimized operating data determined in this way can be saved in a simple manner for repeated feed materials, and the vibrating screen machine can be adjusted for these materials by pressing a button if necessary.

It is also advantageous if the vibratory screening machine contains measuring technology for automatically measuring and evaluating the vibration of at least one screen surface, preferably all screen surfaces and/or the body of the vibratory screening machine and its control is also configured such that according to the evaluation results An automatic control intervention with respect to the excitation frequency, excitation force, excitation angle and/or feed quantity can be realized. This makes it possible, for example, to detect an overload of the screen surface with "felt formation" via suitable evaluation algorithms by measuring the vibrations of the screen surface and machine body, and to carry out suitable control interventions automatically, for example by increasing the excitation force to increase the amplitude or reduce the supply voltage. Feed amount.

A second aspect of the invention relates to an apparatus comprising a vibratory screening machine according to the first aspect of the invention. In this case, the device has a screening material container connected downstream of the vibrating screening machine and measuring technology, with which the filling level or the inflow container in at least two screening material containers, preferably in all containers, can be automatically measured and evaluated The mass flow or volume flow of the sieving material flow. Furthermore, the mechanical control is designed such that an automatic control intervention with respect to the excitation frequency, the excitation force, the excitation angle and/or the feed quantity per unit time can be realized based on the evaluation results. This makes it possible, for example, on the basis of changes in the fill level, which are determinable, for example, by continuous measurement of the container weight, to draw conclusions about the process material given the known composition of the feed material and to carry out automatically optimized control interventions if necessary, For example, in the case of an unsatisfactory sieving rate, the vibration frequency is increased by increasing the excitation frequency.

A third aspect of the invention relates to the use of a vibratory screening machine according to the first aspect of the invention or an apparatus according to the second aspect of the invention for sorting hot material in bitumen manufacture. The advantages of the invention are particularly evident in this application, since different grit mixtures (recipes) must be carried out depending on the type of bitumen required.

A fourth aspect of the present invention relates to a method for operating a vibratory screening machine comprising one or more exciters, and preferably for operating a vibratory screening machine according to the first aspect of the present invention or a vibratory screening machine according to the first aspect of the present invention. The equipment described in the second aspect. Where the excitation force, the excitation frequency and/or the excitation angle are adjusted during operation of the machine, this preferably takes place independently of one another. This produces the advantageous effects already described in the first aspect.

The adjustment of the excitation force is preferably carried out in this way by changing the unbalance of at least one vibrator, which can be achieved by changing the angular position of two unbalanced weights with a common axis of rotation relative to each other, by changing an unbalance The center of gravity distance from the axis of rotation and/or is achieved by supplying liquid to or removing liquid from a container rotating about an axis of rotation.

It is also preferred that in a vibratory screening machine comprising at least two vibrator devices with at least two vibrators (excitation axes) respectively, the excitation force is adjusted such that the vibration of one or more vibrator devices is changed The excitation angle and thus the resulting total excitation force jointly produced by these exciter arrangements changes.

This is advantageously achieved by changing the phase of the shakers of the at least one shaker arrangement relative to one another and/or changing the position of the at least one shaker relative to the body.

Preferably, a vibratory screening machine comprising two vibrator devices each having two vibrators (that is to say with four vibration axes) is operated in such a way that the two exciters of the first vibrator device are in a common second One direction rotates synchronously with each other, so that the two exciters of the second exciter device rotate synchronously with each other on a common second direction opposite to the first direction, and at the same time make the exciters of the first vibrator device Rotate synchronously with the exciters of the second exciter device and simultaneously change the phase of the two exciters of the first exciter device and the phase of the two exciters of the second exciter device with respect to each other, so that The excitation angle of the two exciter arrangements and thus the resulting total excitation force produced jointly by them is varied.

As mentioned above, the advantages of such a vibratory screening machine are that the exciter can have a simple and inexpensive structure without requiring weight reconfiguration of the machine, and that the rotational mass moment of inertia remains constant when the exciting force is adjusted.

In a preferred embodiment of the method, in a vibratory screening machine comprising at least two preferably automatically synchronizable vibrators, the position of at least one vibrator, preferably all vibrators, is changed relative to the machine body and thus relative to the screen surface. position to adjust the excitation angle during operation. As a result, the "throw distance" of the screen surface of the vibrating screen can be adjusted in a targeted manner.

In a further preferred embodiment, the values for the excitation frequency, the excitation force, the excitation angle and/or the feed quantity per unit time which are suitable for different feed materials are stored in a machine control until a later Said values can be retrieved again for the operation of the vibratory screening machine with such a material at a certain point in time, and the vibratory screening machine can be adjusted, in particular automatically, for an operation with these values via the machine control. In this way the vibrating screen can be quickly and optimally adjusted for each feed material.

In a further preferred embodiment of the method, the vibration of at least one screen surface of the vibrating screen, the vibration of the machine body, at least two screens connected downstream of the vibrating screen and configured for different screen surfaces are determined and evaluated. The change of the material level of the material container and/or the corresponding screening material flow to each container and the adjustment of the excitation force, excitation frequency, excitation angle and/or feed amount per unit time according to the evaluation results. It is advantageous in this way that the vibratory screening machine can be operated fully automatically and automatically optimized through the application of suitable evaluation algorithms in a control loop.

In a further preferred embodiment of the method, the vibratory screening machine comprising at least one vibrator with adjustable unbalance is started in such a way that the vibrator initially has no unbalance or operates with a value less than the predetermined The unbalance reaches a certain rotational frequency and then increases, preferably increasing the rotational frequency further up to the desired operating rotational frequency. In this way it is possible to prevent resonance phenomena to the greatest extent due to the non-resulting unbalance through the resonant frequency of the master. This also makes it possible to produce a smooth synchronization among the vibrators which can be synchronized automatically.

It is also preferred that in such a vibrating screen machine, the unbalance is reduced and preferably canceled when the speed of the vibrating screen machine is reduced, so that the resonance point is also passed through again without excitation.

In a vibratory screening machine comprising a plurality of exciter devices, the total excitation force of which is adjustable, for example by changing the excitation angle of each exciter device, preferably, the above-mentioned start-up process and deceleration process are suitable The ground is realized by the corresponding adjustment of the total excitation force.

Description of drawings

Further embodiments, advantages and applications of the invention emerge from the subclaims and the description now below with reference to the figures. in:

Figure 1 is a schematic diagram of an apparatus of the present invention comprising a first vibratory screening machine of the present invention; and

Fig. 2 is a vertical sectional view along the longitudinal direction of the second vibratory screening machine of the present invention.

Detailed ways

Figure 1 shows a preferred embodiment of the apparatus 1 of the invention for sorting hot sand material for asphalt production, comprising a computer-aided machine control 2, an inventive vibratory screen 3, two screens Material containers 6a, 6b and a supply station 3 for supplying feed material to be screened by the vibratory screen machine 3 . The vibrating screen machine 3 has three wire mesh screen surfaces 4 a , 4 b , 4 c of different mesh sizes and is excited by a single vibrator 5 . The exciter 5 (vibration shaft) has two unbalanced weights 8a, 8b with a common axis of rotation, the angular position of which is adjusted during operation of the machine via a hydraulically actuated adjustment mechanism provided in the vibration shaft. It can be changed continuously between the neutral position (two weights facing each other) and a maximum unbalanced position (two weights are set at the same circumferential position), so as to adjust the degree of unbalance. And continuously adjust the rotational speed of the drive motor of the vibrator 5a, so that in combination with the adjustability of the unbalance, the excitation frequency and the excitation force and the resulting screen surfaces 4a, 4b can be adjusted continuously and independently of each other , 4c vibration frequency and amplitude. The sieving material container 6a, 6b is equipped with a camera 9a, 9b in the region of its inflow, which is connected to the control device 2 (see shown with dashed lines) and is used together with the control device to determine the sieving material flowing into the container 6a, 6b flow. Furthermore, each container is equipped with a weighing cell, which is likewise connected to the control unit (2) (shown in dashed lines) and together with the control unit is used to determine the filling level of the container. As can also be seen, on the body of the vibratory screening machine 3 and on each of its screen surfaces 4a, 4b, 4c, alternatively or additionally, a vibration sensor 10 is provided, which is also connected to the control device 2 (with dotted lines shown) and used together with the control device to measure and evaluate the vibration of each screen surface 4a, 4b, 4c and the body. From further evaluation of the operating data thus determined and knowledge of the composition (recipe) of the feed material, the control device can recognize a possible plant disturbance or a non-optimal operation and, if necessary, in a control loop Appropriate corrections to feed quantity, excitation frequency and/or excitation force are made automatically (see dotted lines leading to supply station 7 and vibration exciter 8 ). It is also possible that the plant is automatically optimized by changes in the above parameters during operation and by measuring and evaluating the effect of these changes on the production results.

FIG. 2 shows a vertical section in the longitudinal direction of a vibratory screening machine 3 comprising a plurality of screen surfaces 4 according to the second invention. The vibrator device 11 provided on the machine body includes two vibrators 5a, 5b that can be automatically synchronized, and the vibrator is equipped with a drive device for speed adjustment and can be adjusted in terms of rotational angle position as the vibrator in Fig. 1 Unbalanced weights 8a, 8b adjusted relative to each other. The whole vibrator device 11 can rotate around a center of rotation D by means of two hydraulic cylinders 12 acting on both sides relative to the body supporting each screen surface 4, so that the excitation angle of the vibration unit 11 relative to the screen surface 4 is continuously adjustable. Therefore, together with the continuous adjustability of the speed of the exciter and the degree of unbalance, a vibrating screening machine 3 is obtained, wherein the exciting force, the exciting frequency and the exciting angle and thus the vibrating frequency, the amplitude and the projecting distance are continuously adjustable and are adjustable independently of each other over a wide range.

Claims (14)

1. A vibration screening machine comprising a plurality of exciters, characterized in that the excitation force, excitation frequency and/or excitation angle are adjustable during the operation of the vibration screening machine (3), wherein the vibration screening machine (3) There are two exciter devices with two exciters (5, 5a, 5b) respectively, wherein the two exciters (5, 5a, 5b) of the first exciter device are used in a common The synchronous rotation on the first direction of rotation is synchronous or synchronizable, and the two exciters (5, 5a, 5b) of the second exciter device are designed to rotate in a common second direction opposite to the first direction of rotation. The synchronous rotation of is synchronous or synchronizable, while each exciter (5, 5a, 5b) of the first exciter device and each exciter (5, 5a, 5b) of the second exciter device are Synchronous or synchronizable and the phases of the two exciters (5, 5a, 5b) of the first and second exciter devices are changeable, respectively, in order to change the respective exciter devices (11 ) of the excitation angle and thus the resulting total excitation force jointly produced by the individual exciter devices can be adjusted. 2. The vibrating screening machine according to claim 1, characterized in that the exciting force, the exciting frequency and/or the exciting angle are adjustable independently of each other during the operation of the vibrating screening machine (3). 3. The vibrating screening machine as claimed in claim 1, characterized in that the vibrating screening machine has exactly two exciter arrangements, each having two exciters (5, 5a, 5b). 4. The vibratory screening machine according to one of the preceding claims 1 to 3, characterized in that the excitation force, the excitation frequency and/or the excitation angle are continuously adjustable. 5. The vibrating screening machine according to claim 1, characterized in that the vibrating screening machine (3) has a machine control (2) in which the excitation frequency, excitation frequency, and vibration frequency are stored for different feed materials. Force, angle of excitation and/or feed quantity per unit time and can be taken again at a later moment for the operation of vibratory screening machine (3) utilizing such a feed material, and via the machine control device ( 2) The vibration screening machine (3) can be adjusted for an operation using stored values. 6. The vibratory screening machine according to claim 1, characterized in that the vibratory screening machine (3) is equipped with means for automatically measuring and evaluating at least one screen surface (4, 4a, 4b, 4c) and/or the vibration of the machine body, and is used to automatically adjust the excitation frequency, excitation force, excitation angle and/or feed amount per unit time according to the evaluation results. 7. Comprise the equipment (1) of the screening material container (6a, 6b) that connects behind the vibrating screening machine (3) according to the vibrating screening machine (3) described in one of the preceding claims 1 to 6, characterized in In that the device (1) is equipped with means for automatically determining a change in the filling level in at least two sieving material containers (6a, 6b) and/or the corresponding sieving material in the sieving material containers (6a, 6b) Flow rate, and used to automatically adjust the excitation frequency, excitation force, excitation angle and/or the feeding amount per unit time according to the measured value. 8. Use of the vibrating screen machine (3) according to one of the preceding claims 1 to 6 for sorting hot material during asphalt production. 9. Use of the plant (1) according to the preceding claim 7 for sorting hot material in asphalt production. 10. Method of operating a vibratory screening machine (3) comprising two vibrator devices (11) respectively having two vibrators (5, 5a, 5b), characterized in that the first vibrator device The two exciters (5, 5a, 5b) rotate synchronously with each other on a common first direction of rotation, so that the two exciters (5, 5a, 5b) of the second exciter device rotate in a common direction opposite to the first direction. Rotate synchronously with each other in the second direction of one direction, wherein the exciters (5, 5a, 5b) of the first exciter device and the exciters (5, 5a, 5b) of the second exciter device Rotate synchronously and change the phase of the two exciters (5, 5a, 5b) of the first and second exciter devices, respectively, so as to change the excitation angle of the corresponding exciter devices and thereby change the The combined total excitation force produced by the two exciter devices. 11. according to the described method of claim 10, it is characterized in that, in a machine control device (2) that is used for vibratory screening machine (3), store the excitation frequency that is applicable to different feed material, excitation force, excitation frequency. Vibration angle and/or the value of the feed quantity per unit time and to a later time to take said value again, for the vibrating screening machine (3) utilizes the operation of a such feed material, and via this machine control device (2) Make the vibratory screening machine (3) adjusted for an operation with these values. 12. The method according to claim 10, characterized in that the vibration of at least one screen surface (4, 4a, 4b, 4c) and/or the machine body of the vibratory screening machine (3) is determined and evaluated and adjusted according to the evaluation result Excitation force, excitation frequency, excitation angle and/or feed amount per unit time. 13. The method according to claim 10, characterized in that at least two sieving material containers (6a) connected behind the vibrating sieving machine (3) and configured for their different sieve surfaces (4b, 4c) are determined , 6b) the change of material level and/or the corresponding sieving material flow rate in the sieving material container (6a, 6b) and according to the numerical value of determination, adjust excitation force, excitation frequency, excitation angle and/or unit time supply amount. 14. The method as claimed in claim 12 or 13, characterized in that the determination and adjustment take place automatically in a control loop.

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