Screen mesh

Abstract

A multi-deck screen (10) for screening bulk material comprises a first deck (20, 40, 140) holding a first screening medium (30) and a second deck (20, 40, 140) stacked below the first deck (20, 40, 140), the second deck holding a second screening medium (50). The first and second layers (20, 40, 140) of the stack are connected and supported by uprights (60, 61, 62, 63) extending between the layers (20, 40, 140) towards a first end (100) and an opposite second end (110) of the layers (20, 40, 140). Each deck (20, 40, 140) comprises a frame (70) having a first side wall (80), an opposite second side wall (90), and each of the first and second decks (20, 40, 140) comprises, on each side wall (80, 90) of the frame (70), at least one longitudinally centrally positioned unbalanced motor (120, 130) for independently vibrating the first and second decks (20, 40, 140).

Description

Technical Field

[0001] The present invention relates to a screen for screening materials, and more particularly to a vibrating multi-layer screen for screening bulk materials. Background Art

[0002] For the processing of bulk materials such as stones, minerals, industrial and civil waste including building materials, a variety of crushers have been developed to produce crushed products for subsequent processing or subsequent disposal. Existing crushers include cone crushers, impact crushers, vibrating crushers and jaw crushers. Crushers can also be divided into mobile crushers and stationary crushers. The mobile crusher can be conveniently transported from one location to another, and the stationary crusher is designed for large fixed facilities, which are assembled on-site in environments such as quarries or mines and remain operational until the raw material source is exhausted.

[0003] Generally, crushers are provided with screens for sizing and / or removing materials before crushing to prevent crusher blockage and improve crusher performance. Screens can also be used for sizing the crushed materials.

[0004] Generally speaking, well-known screens are typical vibrating screens, which are composed of one to four layers for sizing bulk materials and a vibrating mechanism or an unbalanced motor. A screening medium is held on the layers, and the vibrating mechanism or the unbalanced motor is used to vibrate the screen to achieve the screening action. In many well-known screens, multiple layers of the screen usually share a single vibrating mechanism or unbalanced motor, so all layers are vibrated simultaneously by the shared vibrating mechanism or unbalanced motor. The screening action can be circular motion, linear motion, elliptical motion of the screen or a combination of multiple motions, and in the case where multiple layers share a vibrating mechanism or unbalanced motor, each layer exhibits the same screening action.

[0005] The screen can also be installed at different layer inclination angles as required, and other parameters, such as the type of screening medium, etc., can be varied according to application requirements.

[0006] However, well-known screens have many disadvantages. For example, well-known vibrating multi-layer screens usually have to adopt heavy steel structures to withstand the forces generated by the shared vibrating mechanism, and the screening efficiency is low, especially for applications where the screening medium at the top layer of the screen has large openings and the screening medium at the lower layer has small openings. Therefore, the selected parameters of the screen must be compromised for each layer, and the best screening action for each layer cannot be achieved. In addition, since each layer must vibrate in the same way, it is impossible to vary the screening action between layers.

[0007] CN2865870U describes a sieve which consists of three inclined levels arranged in sequence, and each level has a relatively complex vibration mechanism which relies on counterweights connected by shafts arranged on both sides of the level. However, this sequential level structure requires a considerable amount of space and is not a single multi-level unit. The shafts required for the vibration mechanism of the level may impair the screening efficiency, and the vibration mechanism cannot be customized and / or coordinated as required according to the screening actions required at the level.

[0008] The object of the present invention is to overcome at least some of the problems of the prior art. Summary of the Invention

[0009] In one aspect, there is provided a multi-level sieve for screening bulk materials, which includes a first level holding a first screening medium and a second level located below the first level and holding a second screening medium. The second level is connected to the first level by columns. Each level includes a frame having a first side wall, an opposite second side wall, and a first end and an opposite second end. At least one longitudinally centered unbalanced motor is included on each side wall of the frame in at least one of the first level and the second level for independently vibrating the first level and the first level.

[0010] In one aspect, there is provided a multi-level sieve for screening bulk materials, including a first level holding a first screening medium and a second level stacked below the first level and holding a second screening medium. The stacked first level and second level are supported and connected by columns which extend between the levels towards the respective first and second opposite ends of the levels. Each level includes a frame having a first side wall and an opposite second side wall. At least one longitudinally centered unbalanced motor is included on each side wall of the frame in each of the first level and the second level for independently vibrating the first level and the first level.

[0011] Using a centered unbalanced motor on at least one level allows for independent control and operation of at least some or all of the screening levels to obtain optimal screening performance.

[0012] In some embodiments, at least one of the first level and the second level includes at least one longitudinally centered unbalanced motor on each side wall of the frame for vibrating the first level and / or the second level such that the vibrations applied to the first level and the second level are independent or separate from each other.

[0013] The first level and the second level are coupled to the columns via shock absorbers.

[0014] In some embodiments, each deck includes at least one unbalanced motor positioned longitudinally centered on each sidewall of the frame. Accordingly, a circular screening motion of the screening deck can be achieved.

[0015] In some embodiments, the multi-deck screen includes at least three decks, wherein the first deck and the second deck share at least one longitudinally centered unbalanced motor on each sidewall of the frames of the first deck and the second deck. Accordingly, the decks sharing the unbalanced motor can be configured for the same screening motion.

[0016] In some embodiments, the unbalanced motor is mounted centered on the sidewall. Accordingly, the sidewall serves to directly support the unbalanced motor for optimal transmission of the vibration force.

[0017] In some embodiments, each deck including the at least one longitudinally centered mounted unbalanced motor on each sidewall includes two longitudinally centered mounted unbalanced motors on each sidewall. Accordingly, a non-circular screening motion, such as a linear or elliptical screening motion, can be achieved.

[0018] In some embodiments, each unbalanced motor includes an encoder. The encoder facilitates the coordination of the unbalanced motors.

[0019] In some embodiments, the encoder is integrated with the unbalanced motor, thereby protecting the encoder and facilitating effective communication between the encoder and the unbalanced motor.

[0020] In some embodiments, the encoders are all rotary encoders, and the rotary encoders are mounted on the shafts of the unbalanced motors. Accordingly, feedback on the rotational speed of the shafts can be obtained.

[0021] In some embodiments, the multi-deck screen further includes an inverter that can communicate with the unbalanced motors to control the unbalanced motors. The inverter serves to facilitate adjustment of the angular position and speed of the motor shafts and to control the angular position of the shafts as needed.

[0022] In some embodiments, the multi-deck screen further includes a central processing unit that communicates with the unbalanced motors 120, 130, the encoders, and the inverter.

[0023] In some embodiments, the central processing unit is configured to coordinate the operation of the unbalanced motors.

[0024] In some embodiments, the tilt angle of each deck is the same or different.

[0025] In some embodiments, each deck includes at least one shock absorber. The shock absorber can be located at each corner of the deck and reduce the vibration force on the deck and the supporting steel structure.

[0026] In some embodiments, the shock absorber includes a coil or a spring, such as a helical spring, a rubber spring or an air spring. Coils and springs are effective shock absorbers.

[0027] In some embodiments, the multi-deck screen further includes a retaining curtain that extends between the decks to protect side plates and the like. The retaining curtain also prevents materials from falling off the deck.

[0028] In some embodiments, the present invention extends to a crusher system including the multi-deck screen as described above. Thus, the crusher system can include a screen and other elements, such as a feed chute or a conveyor.

[0029] The longitudinal direction of the screen can define the machine direction, the lateral direction of the screen is transverse to the machine direction, and the vertical direction of the screen is orthogonal to the machine direction and the lateral direction. In some embodiments, the respective rotation axes of the unbalanced motors are arranged in the lateral direction, i.e., orthogonal to the machine direction and the vertical direction.

[0030] Due to the independently controllable decks of the multi-deck screen of the present invention, coarse and fine materials can be separated by a single multi-deck screen as needed, and the material to be screened can be fed to any deck of the screen as needed. Therefore, due to the independently operable demand-controllable decks, the multi-deck screen of the present invention can be customized as needed to accommodate a wide range of screening operations.

[0031] The multi-deck screen of the present invention can be connected to an automatic screening system, which may include additional sensors and adjust parameters according to the feedback of the sensors. This can be done with or without a PLC (programmable logic controller). BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will now be described by way of example only with reference to the drawings, in which:

[0033] Figure 1 is a top and side perspective view from above of a first embodiment of a multi-deck screen of the present invention for screening bulk materials, where the screen has three decks, and each deck is provided with a centrally located unbalanced motor and a variable frequency drive (VFD) on each side wall of its respective frame. The unbalanced motor is used to independently vibrate the deck in a circular screening motion, the variable frequency drive (VFD) can communicate with the multi-deck screen, and the variable frequency drive (VFD) is arranged in a cabinet adjacent to the multi-deck screen, and

[0034] Figure 2is a top perspective view from above and one side of a second embodiment of the multi-level screen of the present invention, where the screen has three levels, and each level is provided with two centrally positioned unbalanced motors and two variable frequency drives (VFDs) on each side wall of its frame. The unbalanced motors are used to independently vibrate the levels with a non-circular screening action (such as linear motion), the two variable frequency drives (VFDs) can communicate with the multi-level screen, and the two variable frequency drives (VFDs) are arranged in a cabinet adjacent to the multi-level screen. Detailed Description

[0035] As Figure 1 shown, the first embodiment of the multi-level screen of the present invention is generally represented by reference numeral 10, which is composed of a first upper screening level 20, a second or intermediate screening level 40 provided below the first screening level 20, and a third or lower screening level 140 provided below the second screening level 40. Therefore, the multi-level screen 10 is an integral multi-level screen 10 in which the first level 20, the second level 20, and the third level 140 are stacked.

[0036] From Figure 1 it can be deduced that the levels 20, 40, 140 of the multi-level screen are arranged substantially horizontally accordingly, and the levels 20, 40, 140 are vertically stacked on top of each other. Figure 1 The arrangement shown helps to achieve a compact structure and helps the material to fall from the first screen to the second screen, and so on.

[0037] To produce sized products, the first level 20 is provided with a first level screening medium 30, the second level 40 is provided with a second level screening medium 50, and the third level 140 is provided with a third level screening medium 170. The sizes of the screening media 30, 50, 170 are designed to produce oversize and throughput products as required.

[0038] The first screen medium 30 provided in the first level 20 may include openings larger than those in the second screen medium 50, and the third screen medium 170 may include openings smaller than those of the second screen medium 50. Therefore, in some embodiments, one or more of the levels 20, 40, 140 are configured to produce different oversize products. For example, the levels 20, 40, 140 may be configured to produce different oversize products. By independently controlling the vibration of the level according to the aspects described in detail herein, the vibration of a certain level among the levels 20, 40, 240 can adapt to the material screened in the corresponding level of the multi-level screen to achieve optimal screening.

[0039] In this embodiment, each of the levels 20, 40, 140 is structurally identical or similar and consists of a frame 70 having a first sidewall 80, a second sidewall 90 disposed opposite the first sidewall 80, and a first end 100 and an opposite second end 110, wherein the second end 110 is open to define the size of a set screen discharge end 115 for discharging the screened material from the screen 10. The stacked first level 20, second level 40, and third level 140 are supported and connected by columns 60, 61, 62, 63 that extend between the levels 20, 40, 140 toward the first end 100 and the opposite second end 110 of the levels 20, 40, 140. Each of the levels 20, 40, 140 may have a different tilt angle such that the levels 20, 40, 140 are tilted according to the needs of the screening operation. The tilt angle can be selected based on the material velocity and overall screening efficiency and can be defined prior to use and fixed at that angle.

[0040] The respective columns among columns 60, 61, 62, 63 extend between all of the levels 20, 40, 140. Accordingly, the respective levels among the levels 20, 40, 140 can be connected and / or suspended by each of the columns 60, 61, 62, 63.

[0041] Columns 60, 61, 62, 63 extend in a substantially vertical direction. Columns 60, 61, 62, 63 extend in a direction that can be substantially transverse to the horizontal extension of the levels 20, 40, 140.

[0042] Two columns can be provided on each lateral side of the levels 20, 40, 140. With this configuration, the weight of the screen can be reduced.

[0043] In accordance with aspects described in detail herein, by providing respective unbalanced motors for the respective levels of levels 20, 40, 140, it helps to increase the screen area because the respective unbalanced motors among the plurality of unbalanced motors do not need to accelerate any structure other than the level to which they are associated (i.e., the level to which they are mounted).

[0044] In some embodiments, the levels 20, 40, 140 can be structurally different. For example, the first level 20 can include a feed box for receiving the material and thus is structurally different.

[0045] In some embodiments, each of the levels 20, 40, 140 is provided with a centrally located unbalanced motor 120, 130 on each sidewall 80, 90 of its frame 70, respectively, for independently vibrating the three levels 20, 40, 140 in a circular screening motion. Thus, the screening motion of each of the levels 20, 40, 70 can be independently controlled to obtain optimal screening performance. Each unbalanced motor 120, 130 can be equipped with a selected counterweight as needed, depending on the vibration characteristics required for the screen mesh.

[0046] The longitudinal direction of the screen mesh defines the machine direction x, the lateral direction z of the screen mesh is transverse to the machine direction x, and the vertical direction y of the screen mesh is orthogonal to the machine direction x and the lateral direction z. In some embodiments, the respective rotational axes of the unbalanced motors 120, 130 are arranged in the lateral direction z, i.e., orthogonal to the machine direction x and the vertical direction y.

[0047] In some embodiments, as shown, each unbalanced motor 120, 130 is mounted directly and centrally on the sidewalls 80, 90. Each unbalanced motor 120, 130 is provided with an associated encoder to provide feedback on the performance (such as output, shaft speed, etc.) of the unbalanced motors 120, 130. The encoder can be integrated in or included in the unbalanced motors 120, 130, and in one embodiment, the encoder is a rotary encoder mounted on the drive shaft of the unbalanced motors 120, 130. A suitable encoder is an absolute encoder, which provides accurate information about the position of the motor shaft and has a safety function in the event of a power failure.

[0048] Variable frequency drives (VFDs) 180, 181, 182 can also communicate with the unbalanced motors 120, 130 to control the speed of the unbalanced motors 201, 130 on each of the levels 20, 40, 140 and to assist in monitoring the screening motion. In the present embodiment, a single VFD 180 controls the two unbalanced motors 120, 130 of each of the levels 20, 40, 140, thus providing three VFDs 180, 181, 182, which communicate with the respective levels 20, 40, 140. The VFDs 180, 181, 182 can be housed in a cabinet 190 adjacent to the multi-level screen mesh 10. The typical maximum distance between the motors 120, 130 and the VFDs 180, 181, 182 in the cabinet 190 can be approximately 150 meters, but depends on the cable, fuse, and temperature.

[0049] As described above, the unbalanced motors 120, 130 are provided with encoders, and the VFDs 180, 181, 182 can be adjusted to, inter alia, synchronize the angular position and speed of the motor shafts, etc.

[0050] As will be understood by those skilled in the art, the exact types of encoders and VFDs 180, 181, 182 to be used with the multi - deck screen 10 of the present invention can be selected based on the functions required of the multi - deck screen 10 and the types of motors 120, 130 employed.

[0051] As shown, each deck 20, 40, 140 is provided with shock absorbers 150 that extend between the side walls 80, 90 and the columns 60, 61, 62, 63 to modulate the vibration of the decks 20, 40, 140. As needed, suitable shock absorbers 150 can be coil springs, rubber springs (Marsh Mellow), or air spring shock absorbers 160. The shock absorbers 150 allow movement of the screen 10 and the decks 20, 40, 140 and serve to reduce the dynamic forces on the structure of the screen 10 and the decks 20, 40, 140. The shock absorbers 160 can also stabilize the multi - deck screen 10 and the decks 20, 40, 140.

[0052] According to an embodiment herein, the respective decks in the decks 20, 40, 140 can be suspended by a set of such shock absorbers 150, such as at least four shock absorbers, wherein the respective shock absorbers in the set connect the respective columns among the columns 60, 61, 62, 63 to the respective decks.

[0053] The shock absorbers of the set can be directly attached to the respective columns and directly attached to the respective decks, such as directly attached to the side walls of the decks. Thus, the respective vibrations of the decks can be isolated from the columns and other decks.

[0054] In one embodiment of the present invention, the screen 10 is further provided with a curtain extending between the decks (20, 40, 140) to protect the side plates from material impact.

[0055] Figure 2 A top - down perspective view from above and one side of a second embodiment of the multi - deck screen 10 of the present invention is shown, the screen being substantially similar to Figure 1 the screen 10. Thus, the same numerals represent the same parts. However, in this embodiment, the screen 10 has three decks 20, 40, 140, and each deck 20, 40, 140 is provided with two centrally - mounted unbalanced motors 120, 130 on each side wall 80, 90 of its frame 70 to independently vibrate the decks 20, 40, 140 in a non - circular screening motion, such as a linear motion or an elliptical motion.

[0056] In this embodiment, each of the levels 20, 40, 140 requires two VFDs to control a pair of unbalanced motors 120, 130 on opposite sides 80, 90 of each of the levels 20, 40, 140. Accordingly, the cabinet 190 is provided with six VFDs 181, 182, 183, 184, 185, 186. The VFDs 181, 182, 183, 184, 185, 186 are adjustable to, inter alia, synchronize the angular positions and speeds of the motor shafts and control the shaft angular positions of the motors 120, 130 on the same side 80, 90 of each of the levels 20, 40, 140 to effect different stroke motions such as linear and elliptical motions.

[0057] In another embodiment of the present invention, if desired, any two of the levels 20, 40, 140 of the multi-level screen 10 may share the unbalanced motors 120, 130 on each side wall 80, 90 of the level frame 70.

[0058] In use, feed is conveyed to the screen 10, for example via a feed box (not shown), for screening. The screen 10 is operated such that the screening medium 30 of the first upper level 20 screens the material to produce a first screen oversize product. Typically, the size of the first level screening medium 30 is set to set the size of the first classified screen oversize product according to the desired size of the crushed product. The oversize product is discharged from the discharge end 115 of the first level 20. The throughput product from the first level 20 then extends through the screening media 50, 170 of the second and third levels 40, 140, respectively, in a similar manner.

[0059] Since at least one of the levels 20, 40, 140 is provided with at least one longitudinally centered unbalanced motor 120, 130 on each side wall 80, 90 of the level frame 70, the levels 20, 40, 140 can vibrate independently, whereby the desired vibration characteristics and screening performance of the levels 20, 40, 140 can be individually optimized as required. Encoders associated with each of the unbalanced motors 120, 130 permit coordination of the unbalanced motors 120, 130, whereby the operation of the unbalanced motors 121, 130 can be synchronized as required. In addition, variable frequency drives used with the unbalanced motors also assist in controlling the operating speeds of the unbalanced motors 120, 130. Accordingly, the levels 20, 40, 140 of the multi-level screen of the present invention can be controlled separately and independently in a coordinated manner according to the requirements of optimal screening. The overall operation of the screen 10 of the present invention, and in particular the individual levels 20, 40, 140, can be controlled by a central processing unit that communicates with the unbalanced motors 120, 130, the encoder, and the variable frequency drive.

[0060] In some embodiments, the central processing unit 191 may be configured to coordinate the operation of the unbalanced motors 120, 130 such that the unbalanced motors 120, 130 are synchronized.

[0061] The central processing unit may communicate with the unbalanced motors 120, 130, the encoder, and the frequency converter by means of a physical connection, such as a wired connection.

[0062] The central processing unit may be housed, for example, in the cabinet 190.

[0063] If desired, the screen 10 of the present invention may be provided with a feed box for receiving and discharging bulk materials. If desired, the levels 20, 40, 140 of the screen 10 may also be inclined as required.

[0064] Accordingly, the screen 10 of the present invention, particularly the respective levels 20, 40, 140, may be constructed according to the desired screening parameters to achieve efficient screening. Thus, the screen 10 may be used as a general-purpose screen and may be used to screen both coarse and fine materials simultaneously, while the stroke shape (circular, non-circular, linear, elliptical, etc.) of each level 20, 40, 140 may be adjusted as required. The combined use of the unbalanced motor and the encoder enables simple vibration and screening actions. Since the screen may be made of a lighter steel structure and a dedicated unbalanced motor is provided for each level 20, 40, 140, the screening area on the screening medium may also be increased. As a result, the first level 20 may have a larger opening in the screening medium 30, and the second level 40 and the third level 140 may have smaller openings, without compromising the screening efficiency and without the need to use multiple screens to obtain the final product. In short, optimal screening can be achieved regardless of the size of the bulk material fed and the desired separation parameters.

Claims

1. A multi-level sieve (10) for screening bulk materials, comprising: A first level (20, 40, 140), the first level (20, 40, 140) holding a first screening medium (30) A second level (20, 40, 140), the second level (20, 40, 140) being stacked below the first level (20, 40, 140) and holding a second screening medium (50), Wherein the stacked first and second levels (20, 40, 140) are supported and connected by columns (60, 61, 62, 63), the columns (60, 61, 62, 63) extending between the levels (20, 40, 40) towards a first end (100) and an opposite second end (110) of the levels (20, 40, 40) Each level (20, 40, 140) includes a frame (70), the frame (70) having a first side wall (80), an opposite second side wall (90), Wherein each of the first and second levels (20, 40, 140) includes at least one longitudinally centered unbalanced motor (120, 130) on each side wall (80, 90) of the frame (70) for independently vibrating the first and second levels (20, 40, 140).

2. The multi-layer sieve (10) according to claim 1, wherein, Each level (20, 40, 140) includes at least one longitudinally centered unbalanced motor (120, 130) on each side wall of the frame (70).

3. The multi-layer sieve (10) according to claim 1, comprising at least three layers (20, 40, 140), wherein, The first and second levels (20, 40, 140) share at least one longitudinally centered unbalanced motor (120, 130) on each side wall of the frames (70) of the first and second levels.

4. The multi-layer screen (10) according to any one of claims 1 to 3, wherein The unbalanced motors (120, 130) are centrally mounted on the side walls (80, 90).

5. The multi-layer sieve (10) according to any one of claims 1 to 4, wherein, Each level (20, 40, 140) including the at least one longitudinally centered unbalanced motor (120, 130) on each side wall (80, 90) includes two longitudinally centered unbalanced motors (120, 130) on each side wall (80, 90).

6. The multi-layer sieve (10) according to any one of claims 1 to 5, wherein, Each unbalanced motor (120, 130) includes an encoder for coordinating the unbalanced motors 120, 130 such that the operation of the unbalanced motors 120, 130 can be synchronized as required.

7. The multi-layer sieve (10) according to claim 6, wherein, The encoder is integrated with the unbalanced motor (120, 130).

8. The multi-layer sieve (10) according to claim 7, wherein, The encoder is a rotary encoder mounted on the shaft of the unbalanced motor (120, 130).

9. The multi-level sieve (10) according to any one of claims 1 to 8, further comprising a frequency converter capable of communicating with the unbalanced motors (120, 130) for controlling the unbalanced motors (120, 130).

10. The multi-level sieve (10) according to claim 9, further comprising a central processing unit (191), the central processing unit (191) communicating with the unbalanced motors 120, 130, the encoder, and the frequency converter, preferably, the central processing unit (191) being configured to coordinate the operation of the unbalanced motors 120, 130.

11. The multi-layer screen (10) according to any one of claims 1 to 10, wherein, The inclination angle of each level (20, 40, 140) is the same or different.

12. The multi-layer sieve (10) according to any one of claims 1 to 11, wherein, Each level (20, 40, 140) includes at least one shock absorber (150), the at least one shock absorber (150) extending between each side wall (80, 90) of the side walls and the corresponding column (60, 61, 62, 63) of the columns, for modulating the vibration of the level (20, 40, 170).

13. The multi-layer screen (10) according to claim 12, wherein, The shock absorber (150) includes a coil or a spring (160).

14. The multi-level sieve (10) according to any one of claims 1 to 13, further comprising a retaining curtain extending between the levels (20, 40, 140) to protect the side plates.

15. A crusher system, comprising the multi-level sieve (10) according to any one of claims 1 to 14.

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