EP1740319B1 - Vibrating sieve machine and method for operation of a vibrating sieve machine - Google Patents

Description

The invention relates to a Schwingsiebmaschine, a system with the Schwingsiebmaschine, a use of Schwingsiebmaschine or the system and a method for operating a Schwingsiebmaschine according to the preambles of the independent claims.

Vibrating screens are used in the construction industry for classifying chippings or gravel according to the principle of "litter screening". In this case, the vibrating screening machine is designed with respect to screen covering and Sieberregung such that it provides optimum results in terms of screen performance and selectivity for a given, primarily used for use task material. If the composition (recipe) of the feed material changes, the capacity of the plant can be significantly reduced and suboptimal sieving results achieved. This is a problem especially in hot-vibrating screens in asphalt plants, because depending on the desired asphalt quality different chips recipes are to be processed and short-term renovations on the screening machine due to their arrangement are excluded directly above the hot mineral silo.

It is therefore the object to provide a method for operating a Schwingsiebmaschine and a vibrating screen available that do not have the aforementioned disadvantages of the prior art, or at least partially avoided.

This object is achieved by the method and the vibrating screen according to the independent claims.

A first aspect of the invention relates to a Schwingsiebmaschine with multiple unbalance exciters (exciter waves). Here are the excitement, the excitation frequency and / or the excitation angle during operation of the machine adjustable, preferably independently. In the case of linearly excited vibrating screening machines, the angle of excitation is understood to mean the angle of inclination between the exciting force direction and the separating surface (screen lining). For purely circular vibrating screens, this parameter does not exist. The vibrating screen has two unbalance exciter arrangements or units, each with two unbalance exciters. The two unbalance exciters of a first unbalance exciter arrangement for a synchronous rotation are synchronized or synchronized in a common first direction of rotation and the two unbalance exciters of a second unbalance exciter arrangement for synchronous rotation in a common second, opposite to the first direction of rotation synchronized or synchronized. At the same time, the unbalance exciters of the first unbalance exciter arrangement and of the second unbalance exciter arrangement are synchronized or synchronized with one another. Furthermore, the phase position of the two unbalance exciters of the first unbalance exciter arrangement is mutually variable and the phase position of the two unbalance exciters of the second unbalance exciter arrangement mutually variable to change the respective excitation angle of the first and the second unbalance exciter arrangement and thus to enable adjustment of the two unbalance excitation arrangements together generated total excitation force.

This results in the advantage that the oscillation amplitude, the oscillation frequency and the throw of the vibrating screen or screen decks can be selectively adjusted in many areas, so that the machine can be used for various feed materials and also can be provided with a fully automatic control, which the screening results are continuously determined and evaluated and, where appropriate, the excitement, the excitation frequency, the direction of excitement and / or corrects the feed amount per unit time to ensure optimum operation. Such a vibrating screening machine can also be configured as an "intelligent" self-optimizing vibrating screening machine by automatically varying one or more of the aforementioned parameters during operation, determining their influence on the screening result and thus determining an optimal parameter constellation for the respective feeding material. Also, such Schwingsiebmaschinen, in which the change in the excitation force is achieved by shifting the phase position of several unbalance exciters to each other, the advantage that simple and inexpensive unbalance exciters can be used and that there is no change in the rotational moments of inertia when adjusting the excitation force what is preferred.

In a preferred embodiment, the vibrating screen has exactly two unbalance exciter arrangements, each with two unbalance exciters.

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

Preferably, the vibrating screen machine is equipped with a machine control in which the excitation frequency, the excitation force or imbalance, the excitation angle and / or the feed rate per unit time are stored for different feed materials and recalled at a later time for the operation of the vibrating screen with such feed material and with which the vibrating screening machine can preferably be set automatically for operation with the stored values. In this way, already determined optimized operating data for recurring task materials can be easily archived and the Vibrating screen can be adjusted if required by pressing a button for these materials.

It is also advantageous if the vibratory screening machine has measuring technology for automatically measuring and evaluating the oscillations of at least one screen deck, preferably all screen decks, and / or the machine body of the vibrating screen machine and their control is also configured in such a way that depending on the evaluation results an automatic control intervention with respect to the excitation frequency, the excitation force, the excitation angle and / or the task amount can be done. Thus, for example, from the measured vibrations of screen deck and machine body, an overloading of the screen deck with "carpet formation" can be detected by suitable evaluation algorithms and suitable control interventions can be carried out automatically, e.g. the oscillation amplitude can be increased by increasing the excitation force or the amount of feed can be reduced.

A second aspect of the invention relates to a system with a vibrating screen according to the first aspect of the invention. In this case, the system of the vibrating screen downstream Siebgutsilos and measurement, with which levels in at least two of Siebgutsilos, preferably in all silos, or the mass or volume flows of incoming into the silos Siebgutströme can be automatically measured and evaluated. In addition, the machine control is configured in such a way that, depending on the evaluation results, an automatic control intervention can take place with respect to the excitation frequency, the excitation force, the excitation angle and / or the feed quantity per unit of time. For example, conclusions about the process quality can be derived from the changes in the fill levels, which can be determined, for example, by continuously measuring the silo weights, with known feed material composition, and optionally automatically optimizing control interventions are carried out. For example, in the case of poor selectivity, an increase in the oscillation frequency due to an increase in the excitation frequency.

A third aspect of the invention relates to the use of the vibrating screening machine according to the first aspect of the invention or the plant according to the second aspect of the invention for the classification of hot material in asphalt production. In this use, the advantages of the invention become particularly apparent, since here, depending on the desired Asphaltsorte different split mixtures (recipes) must be driven.

A fourth aspect of the invention relates to a method for operating a Schwingsiebmaschine with two unbalance exciter arrangements, each with two unbalance exciters (exciter waves), preferably for the operation of a vibrating screen according to the first aspect of the invention or a plant according to the second aspect of the invention. In this case, the vibrating screen is operated with two unbalance exciter arrangements, each with two unbalance exciters (ie with four excitation shafts) such that the two unbalance exciters of the first unbalance exciter arrangement are synchronously rotated together in a common first direction of rotation and the two unbalance exciters of the second unbalance exciter arrangement are synchronized with each other in a common second, the unbalance exciter of the first unbalance exciter arrangement are rotated synchronously with the unbalance exciters of the second unbalance exciter arrangement and wherein the phase position of the two unbalance exciters of the first unbalance exciter arrangement to each other and the phase position of the two unbalance exciters of the second unbalance exciter arrangement are changed to each other to change the Excitation angle of the two unbalance exciter arrangements and thus to change the resulting Gesamtterregun of these jointly gskraft.

This results in the advantageous effects already set forth under the first aspect. Also results in such Schwingsiebmaschinen the advantage that the unbalance exciters can have a simple and inexpensive structure without mechanical weight adjustment and remain constant when setting the excitation force, the rotational inertia.

In a further preferred embodiment, suitable variables for the excitation frequency, the excitation force, the excitation angle and / or the amount of application per unit time are stored in a machine control for different feed materials, retrieved at a later time for the operation of the vibrating screen with such a material and the vibrating screening machine preferably set automatically via the machine control for operation with these sizes. In this way, a fast and optimal for each task material setting the vibrating screen is possible.

In further preferred embodiments of the method, the vibrations of at least one screen deck, the vibrations of the machine body of the vibrating screen, the change in the levels of at least two of the vibrating screen downstream and different screen decks associated Siebgutsilos and / or the respective Siebgutströme be determined and evaluated in the silos and in dependence from the evaluation results, the excitation force, the excitation frequency, the excitation angle and / or the task quantity per unit time are set. In this way, the vibrating screen can be operated fully automatic and self-optimizing using suitable evaluation algorithms in a control loop, which is preferred.

• Fig. 1 eine Schemadarstellung einer Anlage mit einer ersten Schwingsiebmaschine; und
• Fig. 2 einen Vertikalschnitt in Längsrichtung durch eine zweite Schwingsiebmaschine.

Further embodiments, advantages and applications will become apparent from the dependent claims and from the following description with reference to FIGS. Showing:

• Fig. 1 is a schematic representation of a system with a first vibrating screen; and
• Fig. 2 is a vertical section in the longitudinal direction through a second vibrating screen.

1 shows a preferred embodiment of a plant 1 for classifying hot chippings for asphalt production, comprising a computerized machine control 2, a vibrating screening machine 3, two screening silos 6a, 6b and a feed station 7 for feeding feed material to be screened by the vibrating screening machine 3. The vibrating screening machine 3 has three screen decks 4a, 4b, 4c of wire mesh of different mesh sizes and is excited by a single unbalance exciter 5. The unbalance exciter 5 (excitation shaft) has two imbalance weights 8a, 8b with a common axis of rotation, the rotational angular position via a arranged in the exciter shaft hydraulically operated adjusting mechanism during operation of the machine continuously between a neutral position (weights are opposite) and a maximum unbalance position ( Weights are arranged in an identical circumferential position) can be changed to adjust the imbalance. In addition, the drive motor of the unbalance exciter 5a is steplessly speed-controlled, so that in conjunction with the adjustability of the imbalance, the excitation frequency and the excitation force and, consequently, the oscillation frequency and the oscillation amplitude of the screen decks 4a, 4b, 4c are infinitely and independently adjustable. The Siebgutsilos 6a, 6b are equipped in the field of their enemas with cameras 9a, 9b, which are connected to the controller 2 (see dashed lines) and together with this serve to determine the incoming into the silos 6a, 6b Siebgutströme. In addition, the silos are equipped with load cells 13, which are also connected to the controller 2 (dashed lines) and serve together with this to determine the Silofüllstände. As can be seen further, are alternatively or additionally arranged on the machine body of the vibrating screening machine 3 and on each screen deck 4a, 4b, 4c of the same vibration sensors 10 which are likewise connected to the control 2 (dashed lines) and together with this the determination and evaluation of the vibrations of the individual screening decks 4a, 4b, 4c and the machine body serve. From a further evaluation of the thus determined operating data and the knowledge of the composition (recipe) of the task material, the controller can detect any system failure or sub-optimal operation and optionally make appropriate corrections in the task amount, the excitation frequency and / or the excitation force automatically within a control loop ( see dashed lines to feed station 7 and unbalance exciter 8). It is also possible that the plant optimizes itself by varying the aforementioned parameters during operation and measuring and evaluating the effects of these variations on the production result itself.

Figure 2 shows a vertical section in the longitudinal direction through the machine body of a second vibrating screen 3 with a plurality of screening decks 4. Arranged on the machine body is an unbalance exciter 11 with two self-synchronizing unbalance exciters 5a, 5b, which, as the unbalance exciter in Fig. 1, respectively variable-speed drives and against each other with respect to their angular position adjustable imbalance weights 8a, 8b are equipped. The entire exciter assembly 11 is about a pivot point D by means of two double-acting hydraulic cylinders 12 relative to the machine body, which carries the screen decks 4, pivotable, so that the excitation angle of the excitation unit 11 with respect to the screen decks 4 is continuously adjustable. Together with the stepless adjustability of the unbalance exciter rotational speed and the imbalances thus results in a Schwingsiebmaschine 3, in which the excitation force, the excitation frequency and the excitation angle and so that the oscillation frequency, amplitude and amplitude of oscillation are infinitely adjustable and can be adjusted independently of each other within wide ranges.

Claims (12)

1. Vibratory screening machine having a plurality of unbalance exciters, characterized in that the excitation force, the excitation frequency and/or the excitation angle are adjustable, especially independently of one another, while the vibratory screening machine (3) is in operation, the vibratory screening machine (3) having two unbalance exciter arrangements each having two unbalance exciters (5, 5a, 5b), the two unbalance exciters (5, 5a, 5b) of a first unbalance exciter arrangement being synchronised or synchronisable for synchronous rotation in a common first direction of rotation and the two unbalance exciters (5, 5a, 5b) of a second unbalance exciter arrangement being synchronised or synchronisable for synchronous rotation in a common second direction of rotation opposite to the first direction of rotation, the unbalance exciters (5, 5a, 5b) of the first unbalance exciter arrangement being synchronised or synchronisable with the unbalance exciters (5, 5a, 5b) of the second unbalance exciter arrangement and the phase position of the two unbalance exciters (5, 5a, 5b) of the first and the second unbalance exciter arrangements in each case being alterable to alter the excitation angles of the unbalance exciter arrangements (11) and thus to allow adjustment of the resultant total excitation force generated by the unbalance exciter arrangements jointly.
2. Vibratory screening machine according to claim 1, characterized in that it has just two unbalance exciter arrangements each having two unbalance exciters (5, 5a, 5b).
3. Vibratory screening machine according to either one of the preceding claims, characterized in that the excitation force, the excitation frequency and/or the excitation angle are steplessly adjustable.
4. Vibratory screening machine according to any one of the preceding claims, characterized in that the vibratory screening machine (3) has a machine controller (2) in which, for different feed materials, the excitation frequency, the excitation force, the excitation angle and/or the feed quantity per unit time can be stored and at a later time retrieved for operation of the vibratory screening machine (3) with such a feed material and the vibratory screening machine (3) being adjustable by means of that controller (2), especially automatically, for operation with the stored values.
5. Vibratory screening machine according to any one of the preceding claims, characterized in that the vibratory screening machine (3) is arranged with means (2, 8) for automatically measuring and evaluating the vibrations of at least one screen deck (4, 4a, 4b, 4c) and/or of the machine body of the vibratory screening machine (3) and for automatically adjusting the excitation frequency, the excitation force, the excitation angle and/or the feed quantity per unit time in dependence upon the results of the evaluation.
6. Plant (1) having a vibratory screening machine (3) according to any one of the preceding claims and having screened material silos (6a, 6b) arranged downstream of the vibratory screening machine (3), characterized in that the plant (1) is equipped with means (2, 9a, 9b, 13) for automatically determining the change in the filling levels in at least two of the screened material silos (6a, 6b) and/or the respective streams of screened material into the silos (6a, 6b) and for automatically adjusting the excitation frequency, the excitation force, the excitation angle and/or the feed quantity per unit time in dependence upon the values determined.
7. Use of the vibratory screening machine (3) or the plant (1) according to any one of the preceding claims for classification of hot material in asphalt production.
8. Method of operating a vibratory screening machine (3) having two unbalance exciter arrangements (11) each having two unbalance exciters (5, 5a, 5b), especially for operating a vibratory screening machine (3) or a plant (1) according to any one of claims 1 to 6, characterized in that the two unbalance exciters (5, 5a, 5b) of the first unbalance exciter arrangement are rotated, synchronised with one another, in a common first direction of rotation and the two unbalance exciters (5, 5a, 5b) of the second unbalance exciter arrangement are rotated, synchronised with one another, in a common second direction of rotation opposite to the first direction of rotation, the unbalance exciters (5, 5a, 5b) of the first unbalance exciter arrangement being rotated synchronised with the unbalance exciters (5, 5a, 5b) of the second unbalance exciter arrangement and the phase position of the two unbalance exciters (5, 5a, 5b) of the first and the second unbalance exciter arrangements in each case being altered to alter the excitation angle of the respective unbalance exciter arrangement and thus to alter the resultant total excitation force generated by the two unbalance exciter arrangements jointly.
9. Method according to claim 8, characterized in that in a machine controller (2) for the vibratory screening machine (3), for different feed materials, suitable parameters for the excitation frequency, the excitation force, the excitation angle and/or the feed quantity per unit time are stored and at a later time retrieved for operation of the vibratory screening machine (3) with such a material, and the vibratory screening machine (3) is adjusted, especially automatically, by means of the machine controller (2) for operation with those parameters.
10. Method according to either one of claims 8 and 9, characterized in that the vibrations of at least one screen panel (4, 4a, 4b, 4c) and/or of the machine body of the vibratory screening machine (3) are determined and evaluated and the excitation force, the excitation frequency, the excitation angle and/or the feed quantity per unit time are adjusted in dependence upon the results of the evaluation.
11. Method according to any one of claims 8 to 10, characterized in that the change in the filling levels of at least two screened material silos (6a, 6b) arranged downstream of the vibratory screening machine (3) and associated with different screen decks (4b, 4c) thereof and/or the respective streams of screened material into the silos (6a, 6b) are determined and the excitation force, the excitation frequency, the excitation angle and/or the feed quantity per unit time is adjusted in dependence upon the values determined.
12. Method according to either one of claims 10 and 11, characterized in that the determination and adjustment is effected automatically within a control loop (2, 5, 9a, 9b, 10, 13).

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