Elastic sieving technique and corresponding large-sized elastic vibration screen

Abstract

An elastic sieving method and corresponding large-sized elastic vibration screen The present invention utilizes a screening surface and a separate sieving machine. A screen mat located on the sieve box is connected to multiple small rectangular screens. While the machine is vibrating, the resonation of screen rods located on the screen mat connected by small rectangular screens are initiated to screen the material and to cause the vibration of the whole vibration screen and realize the conveyance and lamination of materials. Because the screening surface is in a state of resonance, the vibration strength is strong enough to prevent the screen meshes from becoming plugged, allowing for high sieving efficiency. A bearing in the sieving mechanism is installed with a vibration damping ring, placing the bearing in a resonant state, allowing for a low dynamic stress level, which satisfies the process requirement for large-sized vibration screen excitation units with a screening surface as wide as 4800 mm. Thus, the production efficiency of vibration screen is high, the structure of the machine is simple and easy to repair and maintain, and energy consumption is reduced. Furthermore, the dynamic stress level of the sieving machine is low, the reliability is high, and the vibrations are stable. These properties allow the present invention to have a wide range of practical applications, including uses in the coal, metallurgic, chemical and environmental protection fields.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:

FIG. 1 is a front view of structure of the elastic vibration screen.

FIG. 2 is a top view of structure of the elastic vibration screen.

FIG. 3 is a structural drawing of small rectangular screens.

FIG. 4 is a sectional view along the line A-A view of FIG. 3.

FIG. 5 is a structural drawing of a vibration damping ring.

In these figures, 1—Sieve box; 2—Vibration exciter, 3—Back support; 4—Front support; 5—Small rectangular screens; 6—Vibration exciting beam; 5-1—Cross beam; 5-2—Baffle; 5-3—Elastomer, 5-4—Sieve rods; 5-5—Constrained rod.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is an elastic sieving technique that can realize the lamination of materials through integral motion of a sieving machine and complete screening through vibrations of a screen surface. The screen mat on the sieve box 1 is connected to multiple small rectangular screens 5, utilizing integral vibrations of the sieving machine. The resonance of screen rods on a screen mat connected by small rectangular screens is initiated to screen the materials completely. The integral vibration comprising primary vibration of a machine body and a secondary vibration of the screen mat connected by small rectangular screens can aid in the conveyance and lamination of materials. Namely, adopting the technique of separating the vibration of the sieving machine and the vibration of the screen surface, the screen mat is placed in the screen surface with sieve rods supported by elastomer. The screen surface may vibrate vertically against the sieving machine body, but the elastic screen surface prevents horizontal vibration. The sieve rods resonate during the vibration of the sieving machine. In theory, the vibration strength of the screen surface is infinite, but the vibration strength of the sieving machine body is relatively small. The sieve rods and sieve flame are cast into an integral body with special elastic material. The scleroscope hardness of the elastic material can range between 25˜40 A. The working rotation rate of the sieving machine is designed as the basic frequency of the screen surface, which may cause the resonance of the screen surface, so the screen surface will vibrate at a higher strength and the sieving machine body will vibrate at a lower strength and realize the sieving technique of high vibration amplitude and large vibration strength of the screen surface while guaranteeing the reliability of the sieving machine.

The elastic vibration screen used in this invention comprises a power driven system, a front elastic support 4, a back elastic support 3, a sieve box 1 fixed on both front and back elastic supports, a vibration exciter 2 mounted on the sieve box 1, and a screen mat on the sieve box 1. The screen mat comprises multiple small rectangular screens 5 where the number of rectangular screens 5 is determined by the length and width of the sieve box—the longer and wider the sieve box is, the larger the number is, and vice versa. If the screen surface is 7 m long and 4.8 m wide, the size of rectangular screen 5 is set as 1×0.6 m, and the number rectangular screens is 56. Single rectangular screens 5 comprise a flute form beam 5-1, a baffle 5-2, and a sieve rod 5-4 mounted in the flute form beam 5-1. There is a constrained rod 5-5 between every two sieve rods 5-4, and there is polyurethane elastomer 5-3 located inside the flute form beam 5-1. Sieve rods 5-4 are fixed along the longitudinal direction of screen surface, but they may vibrate along the vertical direction of screen surface against the flute form beam 5-1. As materials are vibrated along the longitudinal direction of the screen surface it can be difficult to screen materials at the front segment of screen surface because there may be too many materials accumulated there and there are fewer materials at the back segment of screen surface. As a result, the middle segment of the screen surface has the highest probability of successfully screening the materials. Therefore, the present invention sets the distance between every two sieve rods to be the largest at front segment of the screen surface and the smallest at back segment. Intermediate sized sieve rods are located in the middle segment, so the width between sieve rods changes along the longitudinal direction of the screen surface. That is to say, the distance between every two sieve rods at middle segment of screen surface of a screen mat that consists of rectangular screens 5 is shorter than that at the front segment of the screen surface but longer than that at the back segment of the screen surface. The distance between two sieve rods of different segments of screen surface may be arranged according to the actual demand, where the ratio of these distances at front, middle and back segments may be 1.1:1:0.9. The vibration exciter 2 located on the sieve box 1 is connected to the wall of sieve box 1 with the vibration excitation rod 6. There is a vibration damping ring located between a bearing and a shaft inside the bearing support of vibration exciter 2. Numerous of cantilevered vibration damping sheets are located along the internal loop of the vibration damping ring. The cantilevered beam of the vibration damping ring is variably rigid, capable of restraining various harmonious waves and placing the bearing at a lower level of vibration to effectively reduce the dynamic stress level of sieving machine. The dynamic parameter, the ratio of vibration amplitude between sieve rods and the sieving machine, is 5:1, so the vibration strength of the screen surface is at least five times that of conventional vibration screens. The elastic material can be filled and cast according to specific arrangements of screen surfaces.

Claims

1. An elastic screening technique comprising: providing a screen mat connected by multiple small rectangular screens to a sieve box,placing materials required to be screened on the surface of the screen mat, andutilizing vibrations from a vibrating machine to resonate screen rods located on the screen mat to allow for the screening of the materials.

2. The large-sized elastic vibration screen comprising: a power driven system;front elastic support;back elastic support;a sieve box fixed on the front and back elastic supports;a screen mat operably connected to the sieve box;a vibration exciter mounted on the sieve box within the screen mat, comprising multiple rectangular screens, sieve rods located on a front segment of the screening surface of the screen mat with rectangular screens having a longer distance between each rod, while sieve rods on the back segment of screening surface of the screen mat have shorter distance between each sieve rod;a vibration damping ring located between a bearing and a shaft inside the bearing support of vibration exciter.

3. The large-sized elastic vibration screen mentioned as described in claim 2, said rectangular screens comprising a flute form beam, a baffle, and sieve rods mounted in the flute form beam, where a constrained rod is located between every two sieve rods and polyurethane elastomer is located inside the flute form beam.

4. The large-sized elastic vibration screen as described in claim 2, where multiple cantilevered vibration damping sheets are installed in the inner loop of said vibration damping ring.