EP1120170A2 - Screening device - Google Patents

Abstract

A screening device and the use of a screening device are proposed. The sieve device (1) has a support frame (2) which can be set in vibration and a swing frame (6) which is freely oscillating for this purpose. A simple, compact structure with good sieving and conveying capacity is achieved in that the oscillating frame (6) is spring-elastically coupled to the supporting frame (2) via helical spring-like spring elements (5), the main spring axes of the spring elements running in the direction of the tensioning shaft oscillation (7). In addition, guide elements (11) are provided for movably mounting the swing frame (6) on the support frame (2). The screening device is operated in particular at an oscillation frequency of at least 850 oscillations per min at an average speed of approximately 11 m / s and at an average acceleration of the oscillating frame relative to the supporting frame of approximately 2.2 m / s 2. <IMAGE>

Description

The present invention relates to a screening device according to the preamble of claim 1 and a method for operating a screening device according to the preamble of claim 10.

Such a screening device is particularly suitable for so-called difficult to screen Goods such as moist, sticky, caking and / or long-fiber Goods used.

DE 35 03 125, which forms the starting point of the present invention C2 discloses a screening device with the features mentioned at the beginning, the one vibrating support frame and one on the support frame has swinging frame swinging mounted by spring elements. The Cross members of the swing frame extend through window-like Openings in the side cheeks of the support frame go outwards where they are connected to the longitudinal members of the swing frame. Preferably as Push blocks formed spring elements are on each side member distributed in the longitudinal direction at several points, in pairs opposite each other arranged on both sides of a side member. The Push rubber blocks are the only bearing of the swing frame on Support frame, so that the swing frame one of the push rubber elements fixed, largely linear swinging movement relative to the supporting frame can perform. The support frame is used to generate vibrations assigned in particular as a circular oscillator, the only on the support frame and only indirectly via the Push rubber blocks act on the swing frame. The swing frame can swing freely. This known screening device has some Disadvantages.

The spring constant of push rubber blocks is strongly dependent on the Temperature of the push rubber blocks. The vibration behavior is accordingly strongly temperature dependent.

Push rubber blocks are subject to a relatively strong aging. The vibration behavior of push rubber blocks changes accordingly with time; in particular, the vibration behavior deteriorates the push rubber blocks.

When swinging, a relatively large internal friction of the push rubber blocks be overcome so that a strong warming occurs. However, the push rubber blocks must not have certain limit temperatures exceed, otherwise they harden. Accordingly, in the known Sieving device the strength of the vibration - amplitude and frequency or medium speed and acceleration - very limited. The above Vibration frequency that can be achieved for a long time is essentially at a maximum 800 vibrations per min.

By clamping the longitudinal beams between the pairs opposite each other Pushing rubber blocks are supposed to be the vibrating forces - so Vibrations - transverse to the essentially horizontal tension shaft vibration of the swing frame are suppressed, so that essentially only a linear vibration occurs. The superposition of a transverse vibration is not entirely closed in the known screening device avoid, so that the push rubber blocks additionally in this transverse direction swing and accordingly are additionally heated, which the in Bottom line for the maximum tension wave vibration available Vibration frequency and / or amplitude also reduced.

When sieving, the material to be screened should usually pass in one direction screen surface formed by the sieve plate elements are promoted. For this the vibration acting on the support frame normally has a corresponding one main direction of action. To be sufficient Achieving funding in the direction of the screen is, however, an inclination of the Vibration frame or the expansion shaft vibration required. With the known Screening device is in the usually straight training Side member of the swing frame an inclination of the swing frame from about 12 ° to 16 ° relative to the horizontal is required to achieve adequate Receive funding in the direction of the screen. This leads to the Overall length of such a screening device to an undesirably large Overall height.

DE - PS 1 206 372 discloses a similar screening device with a Oscillating frame, which can be set in vibration relative to a supporting frame is so that an alternating tensioning and relaxation of sieve plate elements, which are held by cross members of the frame occurs. Preferably is a swing drive is provided, both on the support frame also acts directly on the swing frame, so that a positively controlled, circular vibration of the swing frame relative to the support frame is produced. Acting between the support frame and the swing frame Springs only serve as a movable support or Guide.

In contrast to that, the positively controlled vibration generation already leads explained free vibration of the swing frame to an increased Construction effort. In addition, the aforementioned screening device has comparable Disadvantages like the screening device according to DE 35 03 125 C2.

DE - PS 1 206 372 describes two alternative designs in which the swing frame is freely swinging, so the swing drive does not act directly on the swing frame. The swing frame is here over spring blocks designed as rubber blocks, which between Longitudinal beams of the swing frame and the support frame are installed. These spring elements are also the same as those mentioned at the beginning Prior art claimed for shear. Accordingly result corresponding disadvantages such as these alternative embodiments in DE 35 03 125 C2.

The present invention has for its object a screening device with free-swinging swing frame of the tensioning shaft swing type and to specify a method for operating such a screening device, which is a more effective sieving, especially for those who have difficulty sieving Enable goods and in particular avoidance or at least Minimizing the disadvantages of the prior art with simple, compact Allow construction.

The above object is achieved by a screening device according to claim 1 or solved a method according to claim 10.

Advantageous further developments are the subject of the subclaims.

An essential idea of the present invention is helical spring trained spring elements that act in the direction of the vibrating shaft, for moving coupling of the swing frame to the support frame and also to provide additional guide elements that the swing frame at least essentially freely movable in the direction of the oscillating shaft store or manage. This leads to several advantages.

The coil spring-like spring elements preferably made of steel are very strong and accordingly allow - also about long periods of time - a vibration with large amplitude and high frequency. Accordingly, a higher acceleration when tensioning the sieve plate elements and consequently a higher or improved sieving performance can be achieved. A higher acceleration is also that Conveying the screenings in the direction of screening is beneficial. This is one of the reasons that the inclination of the swing frame or the tension shaft swing direction in the proposed screening device compared to the state of Technology essential, for example at 3 ° to 5 ° from the horizontal, can be reduced, which is accordingly a considerably smaller Height results.

The provided coil spring type spring elements are much less sensitive as push rubber blocks. In particular, the coil spring type Spring elements virtually not temperature-dependent, so that a more universal Can be used and there is no risk of overheating. In addition, the life of the coil spring type spring elements significantly larger than that of push rubber blocks. Hence result lower operating and maintenance costs.

Another essential aspect of the proposed solution is that the guide elements provided in addition to the spring elements store or guide the swing frame in such a way that it at least essentially free and at least essentially in the direction of the vibrating shaft is guided flexibly. So the desired vibrational movement can can be optimally specified in a simple manner, with the Spring coupling between support frame and swing frame set and can be realized. Accordingly, one can at least essentially linear swing movement of the swing frame relative to the support frame be specified what an optimal sieving effect and a good one Funding in the direction of screening is beneficial. This also enables the spring elements at least essentially not shear stressed become what is beneficial to their lifespan.

If the main direction of action of the vibratory drive is sloping as usual to the direction of the shaft oscillation, in particular around a good one To promote the screenings in the direction of screening, the Guide elements a disturbing vibration of the swing frame across Prevent the direction of the swinging shaft.

Another aspect of the present invention is that the screening device is operated or can be operated with an oscillation frequency that is higher than in the prior art, namely with at least 850 oscillations per min and in particular with approximately 890 oscillations per min. In particular, an average speed of the oscillating frame relative to the support frame of preferably at least 11 m / min and an average acceleration of preferably at least 2.2 m / s ^{2 are} achieved. In this way, a particularly strong clamping wave vibration can be achieved, which enables more effective screening. Furthermore, a better conveyance of the material to be screened is achieved in the conveying direction, so that the inclination of the oscillating frame or the tensioning shaft oscillation can be reduced significantly, in particular to 3 ° to 5 ° to the horizontal, and accordingly the required overall height of the screening device can be reduced.

Fig. 1

einen schematischen Längsschnitt einer vorschlagsgemäßen Siebvorrichtung; und

Fig. 2

eine vereinfachte Draufsicht der Siebvorrichtung gemäß Fig. 1.

Further details, features, properties, advantages and objectives of the present invention are explained in more detail below with reference to the drawing of a preferred exemplary embodiment. It shows:

Fig. 1

a schematic longitudinal section of a proposed screening device; and

Fig. 2

2 shows a simplified top view of the screening device according to FIG. 1.

Fig. 1 shows a proposed screening device 1. This has one Support frame 2 on the by means of an associated swing drive 3 in Vibration is displaceable. The vibratory drive, which is only indicated by dashed lines 3 is in particular connected to the support frame 2 or by the latter held. The oscillating drive 3 is preferably one Linear transducer, d. H. at least essentially only linear ones Generates vibrations.

The support frame 2 is mounted such that it can swing. This is the case with Representative example of the support frame 2 of schematically indicated Support springs 4 mounted and in particular mounted on this.

On the support frame 2, in turn, spring elements 5 are supported, via the one Oscillating frame 6 is coupled to the supporting frame 2 in a resilient manner. The Swing frame 6 is mounted on the support frame 2 such that it at least essentially free in a tensioning shaft vibration direction 7 - ie not positively controlled, but under the influence of the spring elements 5 - back and forth can move around a here referred to as tension wave vibration To execute vibration. Preferably, the swing frame 6 can at least essentially exclusively in the direction of the vibrating shaft 7 swing.

1 and 2 it can be seen that cross member 8 on the support frame 2 and Swing frame 6 are arranged or mounted on these. The cross member 8 extend here at least essentially horizontally and transversely to the direction of the swing shaft 7. The cross members 8 are in the direction of the swing shaft 7 in a row at least essentially in one plane arranged and alternately either from the support frame 2 or from Swing frame 6 worn. When the swing frame 6 in the direction of the swing shaft 7 swings back and forth accordingly Distances between adjacent cross members 8 alternately increased and downsized. This leads to the fact that 8 sieve plate elements carried by the cross members 9, which preferably move from one to the next Extend cross member 8, alternately tensioned and relaxed. This leads to a high acceleration of the sieve plate elements 9 lying screenings (not shown), so that even screen difficult items are screened or can be classified.

The sieve bottom elements or mats 9 can in particular be replaced individually and sufficiently flexible, as is generally known from the prior art Technology known.

In the proposed screening device 1, the spring elements 5 are as steel coil springs. The main spring directions or axes 10 of the spring elements 5 run at least essentially in Direction of shaft oscillation 7.

The coil springs forming the spring elements 5 are preferred Resistant to tension as well as pressure and installed accordingly. However, the spring elements 5 can also be clamped in this way, for example be installed so that they are only subjected to tensile or compressive loads during operation become.

In addition, guide elements 11 are provided between the support frame 2 and the swing frame 6 act and the swing frame 6 with sufficient mobility in the direction of tension shaft 7 on the support frame 2 store.

The aforementioned decoupling of the guide on the one hand and the spring-elastic Vibration coupling by the spring elements 5 leads on the other hand to the fact that the spring elements 5 at least essentially exclusively in their optimal main spring direction and, for example, at least essentially not be subjected to shear. Accordingly, one optimal design of the spring elements 5 possible, so that an optimized or improved vibration behavior of the screening device 1 is achievable, whereupon will be discussed in more detail later. Because of the optimal load the life of the spring elements 5 is also very long. Another The advantage is that the coil springs are available at relatively low cost can be used as spring elements 5.

The spring elements 5 are here in the region of transverse sides 12 of the swing frame 6 arranged, in particular the spring elements 5 engage directly on the transverse sides 12. This results in a simple, compact structure.

The swing frame 6 is at least essentially in the illustration example arranged within the support frame 2. In particular are Side members 13 of the swing frame 6 within the side walls 14 of the Support frame 2 arranged. This enables a simple construction because the Cross member 8 of the swing frame 6, the side cheeks 14 of the support frame 2 don't enforce. However, there are of course others here too Executions possible.

The guide elements 11 are preferably at least essentially here designed like a leaf spring. The swing frame 6 has lateral projections 15 on, for example, by lateral extensions of the transverse sides 12 can be formed. However, the projections 15 are preferably in the form of a projection on the swing frame 6 and in particular on the side members 13 appropriate.

The projections 15 extend through corresponding, not shown Recesses of the side cheeks 14 to the outside and are at their free ends 16 held by the guide elements 11, here two leaf springs in each case, which are at their other end on the support frame 2, especially at the bottom Support projections 17 on the side cheeks 14 of the support frame 2.

The aforementioned guide elements 11 convey in a simple manner and Way an effective management of the swing frame 6, the Swing frame 6 relatively or at least sufficiently light in Tension shaft vibration direction 7 is reciprocable. Due to the leaf spring-like training leads the swing frame 6 in strictness straight or linear swinging movement, but moves on one slightly curved circular path back and forth. Since the deflection or Vibration amplitude is however relatively low, in particular approximately ± 3.2 to 3.5 mm, the swinging movement can at least essentially be considered linear. Tests have also shown that these Tensioning wave oscillating movement enables a very effective sieving.

A particular advantage of the proposed screening device 1 is that that the damping of the vibration of the vibrating frame 6 compared to the Support frame 2 is relatively small, so that the operation is relatively little damping work needs to be done and unnecessary Heating of the moving or elastically deforming parts, in particular the spring elements 5 is avoided.

The total mass or vibrating mass of the support frame 2 is preferred at least essentially 10 times larger than the total mass or vibrating mass of the vibrating frame 6 including the Sieve plate elements 9.

The stretching shaft vibration direction 6 or the main extension plane of the Swing frame 6 is in the illustration example to the horizontal 18 in Sieving direction 19, d. H. in the direction in which the material to be screened is located via the sieve plate elements 9 is transported or conveyed, unless it is through the sieve plate elements 9 falls through, inclined by the angle a. Preferably is the angle of inclination a is approximately 3 ° to 5 °. This is surprisingly low, enough however in the proposed screening device 1 for the promotion in Screen direction 19.

The main swing direction 20 of the swing drive 3 on the support frame 2 vibration is opposite to the direction of sieve 19 to the horizontal 18 inclined by the angle b. The angle of inclination b is here preferably between 30 ° and 50 °, in particular essentially 40 °.

The screening device 1 is preferably designed such that the resonance frequency at least 1100 vibrations per min and in particular at least 1200 vibrations per min. This enables a subcritical Operation of the screening device 1, d. H. a swing below the resonance frequency, at much higher than in the prior art Vibration frequency.

The proposed screening device 1 is preferably designed such that it can be operated with an oscillation frequency of at least 850 oscillations per min and in particular with essentially 890 oscillations per min or higher. The vibratory drive 3 is designed accordingly. The vibrating frame 6 then executes a tensioning shaft vibration in the tensioning shaft vibration direction 7. The amplitude is in particular approximately ± 3.2 to 3.5 mm. Thus, an average speed of the swing frame 6 relative to the support frame 2 of more than 11 m / min and an average acceleration of at least 2.2 m / s ² can be achieved. In this way, a much stronger clamping shaft vibration than in the prior art can be realized, which accordingly results in a more effective screening and a better conveying of screenings in the direction of screening 19.

Claims (11)

Screening device (1) with a support frame (2) which can be set in vibration, a vibrating drive (3) assigned to it and acting exclusively thereon, and a support frame (6) mounted on the support frame (2) and connected via spring elements (5) to this, which at least essentially swing freely in a tensioning shaft vibration direction (7), the support frame (2) and the swinging frame (6) having cross members (8) which are arranged alternately one behind the other in the tensioning shaft vibration direction (7) and in particular carry sieve plate elements (9) which in The direction of the swinging shaft vibration (7) can be alternately tensioned and relaxed,
characterized, that the spring elements (5) are designed as coil springs, the main spring axes (10) of the spring elements (5) running at least substantially in the direction of the oscillating shaft (7), and that in addition to the spring elements (5) guide elements (11) for mounting or guiding the swing frame (6) on the support frame (2) are provided. Screening device according to claim 1, characterized in that the spring elements (5) are built to withstand both tensile and compressive loads and / or that the spring elements (5) have a spring constant of 150 to 300 N / mm, preferably from 190 to 250 N / mm and in particular essentially of 220 N / mm. Screening device according to one of the preceding claims, characterized characterized in that the spring elements (5) exclusively in the area of the two Transverse sides (12) of the swing frame (6) are arranged and / or that the spring elements (5) are arranged within the supporting frame (2). Screening device according to one of the preceding claims, characterized characterized in that the swing frame (6) at least substantially within the support frame (2) is arranged and / or that the swing frame (6) has projections (15) on which the guide elements (11) engage, in particular, the projections (15) being correspondingly Extend recessed side cheeks (14) of the support frame (2) to the outside and the guide elements (11) at the free ends (16) of the projections (15) attack. Screening device according to one of the preceding claims, characterized characterized in that the guide elements (11) are designed as leaf springs are and / or that the guide elements (11) for exclusive and / or at least essentially freely movable in the direction of the oscillating shaft (7) Storage or guidance of the swing frame (6) on the support frame (2) are provided. Screening device according to one of the preceding claims, characterized in that the screening device (1) is designed such that the resonance frequency of the sieve wave vibration is greater than 1100 vibrations per minute, in particular greater than 1200 vibrations per minute, that the screening device (1) can be operated with a subcritical vibration frequency, that the screening device (1) can be operated with an oscillation frequency of more than 850 oscillations per min, in particular essentially with 890 oscillations per min, that in operation the average speed of the oscillating frame (6) relative to the supporting frame (2) is greater than 10 m / min, preferably greater than 11 m / min, and in particular is essentially 12 m / min, and / or that in operation the mean acceleration of the oscillating frame (6) relative to the supporting frame (2) is greater than 2 m / s ² and in particular is essentially 2.2 m / s ² or more. Screening device according to one of the preceding claims, characterized characterized in that the ratio of total mass of the support frame (2) inclusive the oscillating drive (3), provided that it is held by the support frame (2) is, to the total mass of the swing frame (6) greater than 5, preferably is greater than 8, and in particular is essentially 10. Screening device according to one of the preceding claims, characterized characterized in that the main plane of extension of the oscillating frame (6) and / or the sieve surface formed by the sieve plate elements (9) at most 10 °, preferably by less than 8 ° and in particular 5 ° to 3 °, is inclined to the horizontal (18) in the direction of the oscillating shaft (7). Screening device according to one of the preceding claims, characterized characterized in that the screening device (1) is designed such that the Vibratory drive (3) on the support frame (2) in an at least essentially linear main vibration direction (20) acts, in particular where the Main vibration direction (20) is inclined to the horizontal (18), preferably between 30 ° and 50 ° and in particular essentially around 40 °. Method for operating a screening device (1) with an oscillating support frame (2), an associated oscillating drive (3) acting exclusively thereon and an oscillating frame (6) mounted on the support frame (2) and spring-elastically coupled to it via spring elements (5), which vibrates freely at least essentially in a tensioning shaft vibration direction (7), the support frame (2) and the vibration frame (6) having cross members (8) which are arranged alternately one behind the other in the tensioning shaft vibration direction (7) and in particular carry sieve plate elements (9) which alternately tensioned and relaxed in the direction of the oscillating shaft (7),
characterized,
that the screening device (1) with a subcritical vibration frequency of more than 850 vibrations per min, with an average speed of the vibrating frame (6) relative to the supporting frame (2) of at least 11 m / min and / or with an average acceleration of the vibrating frame (6 ) is operated relative to the support frame (2) of at least 2.2 m / s ² . A method according to claim 10, characterized in that a screening device (1) according to one of claims 1 to 9 is used.

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