Vibrating screen for screening aggregates and / or soil
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-04-17
- Publication Date
- 2026-04-02
AI Technical Summary
Existing vibrating screens for aggregates and soils are inefficient in terms of energy consumption and screening efficiency, as they require significant energy to lift the entire material during each vibrational shock.
A vibrating screen design that incorporates a chute-shaped vibration screening deck supported by eccentric shafts, which vibrates mechanically to create continuous circular motion along the screening deck, reducing the need to lift the entire material simultaneously.
This design significantly reduces energy consumption and required operating power while improving screening efficiency by allowing different parts of the material to be lifted at different times, promoting continuous rotation and balanced mass movement.
Smart Images
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Abstract
Description
[Technical field]
[0001] The present invention relates to a vibrating screen for screening aggregates and / or soils, the screen comprising a body and a chute-shaped fixed screening deck fixedly attached to the body by both ends of the solid screening deck, the fixed screening deck comprising fixed screening flat bars forming first screening slots between the fixed screening flat bars, the curved shape of the fixed screening flat bars corresponding to the shape of the fixed screening deck. The vibration properties of the screen are provided by the chute-shaped vibrating screening deck, the fixed screening flat bars and the vibrating flat bars of the vibrating screening deck being arranged in connection with the fixed screening deck such that the fixed screening flat bars and the vibrating flat bars of the vibrating screening deck are adjacent to each other one after the other. [Background technology]
[0002] From EP 2 778 292 B1 a screening and crushing device for aggregates and / or soil is known which has a chute-shaped fixed screening deck, on which blades fixed to a rotating shaft move into screening slots. The shaft is arranged below the screening deck in such a way that only the tips of the blades extend above the screening deck. This known screen is not a vibrating screen, since the shaft and the blades rotate about a linear axis without vibration properties.
[0003] From EP 2581140 B1 (FIG. 1) a vibrating screen is known in which the vibrating screening deck is planar, providing vibration properties without having a fixed screening deck. Thus, moving the material to be screened during each vibration impact requires a lot of energy, since the entire material has to be lifted at once. Summary of the Invention [Problem to be solved by the invention]
[0004] It is an object of the present invention to provide an improved vibrating screen in which the screening efficiency is improved while at the same time the energy consumption and operating power requirements can be significantly reduced. [Means for solving the problem]
[0005] Said object is achieved with a vibrating screen according to the invention, comprising a chute-shaped vibrating screening deck, supported on the body by eccentric shafts and arranged to be vibrated by mechanical power by rotating the eccentric shafts synchronously with each other, whereby each point of the screening deck undergoes a continuous rotational movement along a circular path in the same rotational direction as the eccentric shafts rotate. The vibrating screening deck comprises vibrating flat bars which create second screening slots between the vibrating flat bars, the curved shape of the vibrating flat bars corresponding to the chute shape of the vibrating screening deck. The vibrating flat bars are arranged between the first screening slots, the screening deck being arranged at height levels relative to one another such that during one cycle the vibrating flat bars rise partially one after the other and at different times above the screening surface formed by the upper edges of the fixed screening flat bars in different parts of the fixed screening deck.
[0006] This differs from the vibrating screen known from EP 2581140 B1 mainly because in the present invention a fixed screening deck is also used, on which a vibrating flat bar moves into the screening slot, and both screening decks are cutter shaped, so that the fixed screening deck partially supports the material to be screened temporarily and locally, and the vibrating screen deck lifts different parts of the material to be screened at different times, reducing the energy consumption and the required starting torque, providing a rotation of the material on the screen deck and increasing the screening efficiency.
[0007] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. [Brief description of the drawings]
[0008] [Figure 1] FIG. 1 shows a vibrating screen as known from the prior art document EP 2 581 140 B1 in a view from below with a part of an edge cut away. [Diagram 2] FIG. 2 shows a vibrating screen according to the invention seen from the end, with the end cut away and parts removed from the end of the eccentric shaft 2 . [Diagram 3] FIG. 3 shows a cross-section of a vibratory screening deck according to the present invention in an axonometric projection. [Figure 4] FIG. 4 shows the elements of a fixed screening deck in an axonometric projection. [Diagram 5] FIG. 5 shows a vibrating screen according to the invention in axonometric projection as seen from above, as if one end were cut away. [Figure 6] FIG. 6 shows, in axonometric projection from above, a vibrating screen according to the invention placed in a bucket movable by heavy machinery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0009] The vibrating screen comprises a body 1 with a plate wall and a fixed structure of screening decks 6 and 7 that define a screening space. A chute-shaped fixed screening deck 6 is fixed by its two ends to the body 1. The fixed screening deck 6 may be formed of three adjacent elements according to FIG. 4. The fixed screening deck 6 comprises fixed screening flat bars 8, which create a first screening slot 8a between them. The curved shape of the screening flat bars 8 corresponds to the shape of the chute of the fixed screening deck 6.
[0010] The vibrating screening deck 7 comprises vibrating flat bars 9, which create second screening slots 9a between them, the curved shape of the vibrating flat bars corresponding to the chute shape of the vibrating screening deck 7. The vibrating screening deck 7 is supported in the body 1 by eccentric shafts 2. Both eccentric shafts 2 comprise a throw shaft 2a between their end sections, the central axis of which is at a short radial distance from the axis of rotation of the end sections. The throw shaft 2a therefore rotates eccentrically with respect to the central axis of the end sections of the eccentric shafts 2. The eccentric shafts 2 are rotatably bearing mounted and fixed to the body 1 by body bearings 3 which surround the end sections. The body bearings 3 are shown in FIG. 5 and the fixing flanges of the body bearings 3 are partially shown in FIG. 2 at both ends of the shaft 2. In FIG. 1 the corresponding body bearings 3 can also be seen, which show the rotating motor 13 of the eccentric shafts 2 in a housing 16 and a chain or toothed belt 14 by which the rotation drive is transmitted to the eccentric shafts 2. 1 also shows a chain or belt 15 connecting both ends of the eccentric shafts 2, by means of which the rotational drive is transmitted to another of the eccentric shafts 2, so that the eccentric shafts 2 rotate synchronously with each other. In the present invention, a similar drive arrangement can be used, where the motor is in the housing 16 of the vibrating screen bucket 20 shown in FIG. 6, and the power transmission is in the housing 14.
[0011] The slow shaft 2a is supported by a bearing 5 inside the body tube 4 of the vibrating screening deck 7. The vibrating flat bar 9 is fixed to the body tube 4 by means of a fixing means 4a. The vibrating screening deck 7 formed by the vibrating flat bar 9 can thus be vibrated by mechanical power by rotating the eccentric shafts 2 synchronously with each other, whereby when the eccentric shafts 2 rotate, each point of the vibrating screening deck 7 makes a continuous circular movement in the same rotation direction along a circular path, the radius of which corresponds to the eccentricity between the end parts of the eccentric shafts 2 and the slow shaft 2a. This eccentricity between the body bearing 3 and the bearing 5 of the slow shaft 2a is typically 15-25 mm, for example, in the embodiment of FIG. 6, when the screening decks 6, 7 form a vibrating screening deck of a bucket 20 of a heavy machine, and the body 1 of the screen is fixedly connected to the bucket 20. The vibrating screen bucket 20 can be connected to a boom of a heavy machine with a protrusion 17.
[0012] The rotation speed of the eccentric shaft 2 may for example be in the range of 700-1200 rpm, so that the vibration frequency exceeds the characteristic vibration frequency of the structure of the vibrating screen according to the embodiment. A high rotation speed, i.e. a high vibration frequency, achieves a good screening capacity. For small values of eccentricity, the rotation speed can be in the range of 1200-1500 rpm, in order to achieve a sufficient peripheral speed in said circular path, i.e. a sufficient surface speed of the vibrating screening deck 7 to achieve a sufficiently fast circular movement of the material. The rotation speed can also be lower than the characteristic vibration frequency of the screen, for example 400-500 rpm.
[0013] When the eccentric shaft 2 rotates, the entire rotating mass induces a rotational force in the radial direction of the shaft 2, which is balanced by a counterweight 12 attached to the end of the shaft 2. The distance of the centre of mass of the counterweight 12 from the axis of rotation of the body bearing 3 is a multiple, for example ten times, compared to the eccentricity of the eccentric shaft 2, whereby a counterweight is required which is one tenth of the mass of the screening structure which is movable together with the eccentric shaft 2.
[0014] FIG. 3 shows the connection of the ends of the body tubes 4 to each other using support rods 19 which strengthen the vibratory screening deck 7 .
[0015] The vibrating screening deck 7 comprises a vibrating flat bar 9, which creates a second screening slot 7a between them, the curved shape of which corresponds to the shape of the chute of the vibrating screening deck 7. The vibrating flat bar 9 is arranged in the first screening slot 8a. The screening decks 6, 7 are arranged in relation to each other at such height levels that during one cycle of the eccentric shaft 2 the vibrating flat bar 9 rises partially one after the other at different times above the screening surface formed by the upper edges of the fixed screening flat bars 8 in different parts of the fixed screening deck 6. Due to the chute shape of the screening decks 6 and 7, said circular movement of the screening deck 7 causes the vibrating flat bar 9 of the screening deck 7 to sink below the upper surface of the screening flat bars 8 of the screening deck 6 for about half of said cycle, so that the entire material to be screened does not have to be lifted in any case. During the circular movement of the screening deck 7, the vibrating flat bar 9 first rises above the upper surface of the fixed screening deck 6 from the front edge of the screen, then in the direction of movement the peak of the rise moves towards the rear edge of the screen. Thus, the entire material to be screened is not lifted at the same time. Also, due to the curved shape of the screening decks 6 and 7, the mass transfer is not only up and down motion, but simultaneous up and down motions of different parts of the mass balance each other's influence. In addition, the power requirement at start-up is reduced and the total mass of the screen is reduced as the moving mass of the screen balanced by the counterweight 12 is reduced. At the same time, the material to be screened is provided with a circulating motion, increasing the screening capacity.
[0016] Preferably, the curvatures of the fixed screening flat bar 8 and the vibrating flat bar 9 correspond to each other, whereby the chute-like shapes of the fixed screening deck 6 and the vibrating screening deck 7 correspond to each other. There may be slight differences in the curvatures of the screening decks 6 and 7, as long as the vibrating flat bar 9 stays within the screening slots 8a between the screening flat bars 8. Therefore, the height of the screening flat bar 8 and the vibrating flat bar 9 must be substantially greater than twice the value of the eccentric shaft 2, which is the same as the diameter of the circular motion of each point of the vibrating flat bar 9.
[0017] In a preferred embodiment of the present invention, the fixed screening flat bar 8 and the vibrating flat bar 9 are curved only in the central portion of the screening decks 6 and 7. At the end portions of the screening decks 6, 7, the fixed screening flat bar 8 and the vibrating flat bar 9 are straight. The angle α between the end portions of the screening decks 6 and 7 is in the range of 80 degrees to 120 degrees, preferably 85 degrees to 100 degrees, typically about 90 degrees.
[0018] In a preferred embodiment of the present invention, the upper edges of the vibrating flat bars 9 of the vibrating screening deck 7 have localized protrusions 9a that are offset from one another to facilitate the rotation of the material on the screening deck.
[0019] As shown in Figure 4, the guide slot 8b, which is narrower than the screening slot, is located at the end of the screening slot 8a of the fixed screening deck 6, where the end of the vibrating flat bar 9 of the vibrating screening deck 7 is placed. The vibrating flat bar 9 is thus guided in the center of the screening slot 8a. Also, the side of the fixed screening flat bar 8 may have localized protrusions that support and guide the vibrating flat bar 9 moving into the screening slot 8a.
[0020] The gap between the screening flat bars 8 and the vibrating flat bars 9 determines the size of the fragments of the sieved material, which is influenced by the thickness and distance of the screening flat bars 8 and the vibrating flat bars 9. The elements of the fixed screening deck 6 according to Fig. 4 may be manufactured from screening flat bars 8 having different thicknesses and different screening slots 8a. The vibrating flat bars 9 of the vibrating screening deck 7 according to Fig. 3 may be manufactured with different thicknesses and can be attached to the body tube 4 of the vibrating screening deck 7 at the desired intervals. The size of the fragments to be screened can therefore be easily selected and changed.
Claims
1. A vibrating screen for screening aggregate and / or soil, wherein the screen includes a main body (1) and a chute-shaped fixed screening deck (6) which is fixedly attached to the main body (1) by both ends of the fixed screening deck, the fixed screening deck includes fixed screening flat bars (8), the fixed screening flat bars form a first screening slot (8a) between the fixed screening flat bars and have a curved shape corresponding to the shape of the fixed screening deck (6), The screen includes a vibrating screening deck (7) in the shape of a chute, wherein the vibrating screening deck is supported by the main body by eccentric shafts (2) and is arranged to vibrate by mechanical power by rotating the eccentric shafts (2) synchronously with each other, so that each point of the vibrating screening deck (7) rotates continuously in the same direction along a circular path as the eccentric shafts (2) rotate, and the vibrating screening deck (7) includes vibrating flat bars (9), wherein the vibrating flat bars create a second screening slot (7a) between the vibrating flat bars, and the curvature of the vibrating flat bars corresponds to the chute shape of the vibrating screening deck, the vibrating flat bars (9) are arranged within the first screening slot (8a), and the screening decks (6, 7) are arranged in relation to each other at height levels such that the vibrating flat bars (9) partially rise at different times in one cycle over the screening surface formed by the upper edges of the fixed screening flat bars (8) on different parts of the fixed screening deck (6). A vibrating screen characterized by the following features.
2. The fixed screening flat bar (8) and the vibrating flat bar (9) are curved in the central portion of the screening deck (6, 7), and the fixed screening flat bar (8) and the vibrating flat bar (9) are straight at the end portions of the screening deck. The vibrating screen according to feature 1.
3. The angle between the ends of the aforementioned screening deck is in the range of 80 to 120 degrees. The vibrating screen according to feature 1 or 2.
4. The angle between the ends of the aforementioned screening deck is in the range of 85 to 100 degrees. The vibrating screen according to feature 3.
5. The screening decks (6, 7) form the base of the movable bucket (20) of the heavy machine, and the screen body (1) is fixedly connected to the bucket (20). The vibrating screen according to feature 1.
6. The upper edge of the vibrating flat bar (9) of the vibration screening deck (7) has a localized projection (9a). The vibrating screen according to feature 1.
7. The local protrusions (9a) of the different vibrating flat bars (9) are arranged offset from each other. The vibrating screen according to feature 6.
8. The fixed screening deck (6) has a narrower guide slot (8b) at the end of the screening slot (8a), and the end of the vibrating flat bar (9) of the vibrating screening deck (7) is positioned within the guide slot (8b). The vibrating screen according to feature 1.
9. The side surface of the fixed screening flat bar (8) has a local projection, which supports and guides the vibrating flat bar (9) that moves within the screening slot (8a). The vibrating screen according to feature 1.
10. The curvature of the fixed screening flat bar (8) and the vibrating flat bar (9) corresponds to each other, and thereby the chute shapes of the fixed screening deck (6) and the vibrating screening deck (7) correspond to each other. The vibrating screen according to feature 1.
11. The end portion of the eccentric shaft (2) is attached to the main body (1) by bearing using a main body bearing (3), and an eccentric throw shaft (2a) exists between the end portions of the eccentric shaft (2), and the eccentric throw shaft is eccentric with respect to the end portions and is attached by bearing inside the main body tube (4) of the vibration screening deck (7) (5). The vibrating screen according to feature 1.
12. The eccentricity of the eccentric shaft (2) is in the range of 15 mm to 25 mm, and as a result, the radius of the circular path of vibrational movement is in the range of 30 mm to 50 mm. The vibrating screen according to feature 1.