Composite screen and screening method

Abstract

The present invention discloses a composite screen and a screening method. The composite screen includes a circular screen piece, a ratchet, a drive shaft and a spring screen plate. The circular screen piece and the ratchet are alternately connected in series on the drive shaft. The spring screen plate and the circular screen piece are cross-arranged to form a composite screen surface. When materials enter the screening chamber, materials smaller than the primary screen gap fall onto the spring screen plate, and materials larger than the primary screen gap flow to the discharge port, thereby realizing primary screening. Materials smaller than the secondary screen gap on the spring screen plate fall below the composite screen surface, and materials larger than the secondary screen gap flow to the discharge port along the inclined screen surface formed by the spring screen plate. At the same time, as the ratchet rotates, the composite screen surface generates periodic vibrations, so that the materials obtain additional kinetic energy perpendicular to the screen surface. In the above manner, the present invention and the screening method can improve the loosening kinetic energy of the materials, make the wet and sticky materials loosen well, improve the kinetic energy of the fine materials through the screen, improve the screening efficiency, and have a good screening effect on coal, ore and fine wet and sticky materials.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine screening, in particular to a composite screen and a screening method. Background Art

[0002] With the increasing level of modernization of coal mine production, the important position of coal particle size classification in the coal production system has become increasingly prominent. Designing and manufacturing efficient screening equipment that meets production needs to improve the coal classification level and efficiency is a problem that needs to be solved in the development of fine particle size classification technology.

[0003] Dry screening is used for coal, ore and other materials, mainly for classifying materials with a particle size less than 6mm. In the existing technology, strong vibration screening technology or cross roller screening technology is mainly used.

[0004] The disadvantages of strong vibration screening technology are: large vibration load and high noise;

[0005] The disadvantage of the cross roller screening technology is that the screen surface structure of the cross roller screen is composed of a dome surface formed by circular screen pieces strung on the shaft and a trapezoidal screen cavity formed by the cross arrangement of upper and lower shaft screen pieces. Materials smaller than the width of the screen cavity fall into the screen cavity, and materials smaller than the screen gap fall under the screen to achieve the screening purpose; materials smaller than the width of the screen cavity and larger than the width of the screen gap are carried out of the screen cavity and transported to the discharge port by the friction of the screen pieces in the screen cavity.

[0006] Since the screen cavity has a trapezoidal cross-section, which is equivalent to a material drop pit, the remaining material is completely removed by the friction of the screen. Therefore, the efficiency of material discharge from the screen cavity is very low. The old material cannot be discharged in time, and the new material cannot enter the screen cavity, so effective screening cannot be performed. Especially when the material particle size composition is fine, the screening efficiency is significantly reduced. Summary of the invention

[0007] The main technical problem solved by the present invention is to provide a composite screen and a screening method, which can improve the loosening kinetic energy of the material, make the wet and sticky material loose well, improve the kinetic energy of fine material through screening, improve the screening efficiency, and have a good screening effect on fine wet and sticky materials of coal, ore and similar properties.

[0008] In order to solve the above technical problems, a technical solution adopted by the present invention is: providing a composite screen, which is located in a screening chamber, and has an inlet on one side of the screening chamber and an outlet on the other side.

[0009] An inclined composite screen is provided in the screening chamber. The composite screen comprises a circular screen piece, a ratchet, a driving shaft and a spring screen plate. The circular screen piece and the ratchet are alternately connected in series on the driving shaft. The spring screen plate and the circular screen piece are cross-arranged to form a composite screen surface.

[0010] In a preferred embodiment of the present invention, the circular screen and the ratchet wheel are driven by the driving shaft to perform circular motion along the rotation direction of the driving shaft.

[0011] In a preferred embodiment of the present invention, the spring screen plate includes spring rods on two sides and a middle connecting piece for fixing the spring rods on the two sides.

[0012] In a preferred embodiment of the present invention, the ratchet is composed of unidirectional arc surface teeth, a wheel belly, an axial hole and a keyway. The ratchet is installed on the drive shaft through the axial hole and the keyway. When the ratchet rotates, it performs unidirectional intermittent motion in the inclined direction of the unidirectional arc surface teeth.

[0013] In a preferred embodiment of the present invention, the spring rods of the spring screen plate are forked between the circular screen sheets, the spring screen plate is arranged obliquely, and the ends of the spring rods on both sides of the spring screen plate are tangent to the tooth center circle of the ratchet to form a cross arrangement.

[0014] In a preferred embodiment of the present invention, primary screen gaps of equal width are formed between adjacent circular screen plates on the drive shaft to achieve primary screening of materials.

[0015] In a preferred embodiment of the present invention, secondary screen gaps of equal width are formed between the spring rods and the circular screen plates on both sides of the composite screen surface, and the size of the secondary screen gaps is matched according to the screening particle size.

[0016] In a preferred embodiment of the present invention, the ratchet rotates with the driving shaft, and the gradually changing arc tooth surface of the one-way arc surface gear teeth lifts the spring rod, driving the spring screen plate as a whole to perform a cyclic reciprocating up and down displacement movement along the arc tooth surface.

[0017] In a preferred embodiment of the present invention, the material and the composite screen surface move relative to each other, and the movement direction of the material is perpendicular to the composite screen surface.

[0018] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a screening method for a composite screen, comprising the following steps:

[0019] a) Primary screening material:

[0020] The material enters the screening chamber from the feed port, and the circular screen and ratchet wheel move in a circular motion under the action of the drive shaft.

[0021] Driven by its own weight and the circular screen, materials smaller than the distance between adjacent circular screens, that is, materials smaller than the first-level screen gap, fall down onto the spring screen plate.

[0022] The material with a size larger than the first-level screen gap flows from the top surface of the circular screen piece to the discharge port along the inclination angle of the composite screen;

[0023] b) Secondary screening material:

[0024] Driven by the circular screen, the materials on the spring screen plate, which are smaller than the secondary screen gap, that is, smaller than the gap between the spring rod and the circular screen plates on both sides, fall under the composite screen surface, and the materials larger than the secondary screen gap flow to the discharge port along the inclined screen surface formed by the spring screen plate.

[0025] As the ratchet rotates, the gradually changing arc surface of the one-way arc gear teeth gradually lifts the spring rod and then drops it. The spring rod moves up and down based on the composite screen surface. Each time it passes through the arc tooth surface, it produces an up and down displacement effect. This cycle repeats itself, causing the composite screen surface to vibrate periodically. The vibration direction of the material is perpendicular to the plane where the composite screen surface is located.

[0026] The beneficial effects of the present invention are as follows: the composite screen and screening method of the present invention have good screening effect for fine wet and sticky materials of coal, ore and similar properties, and have low noise pollution and compact structure. They can solve the problems of easy clogging of the screen surface, low screening efficiency, large dynamic load, and high noise in the process of fine particle size classification of dry materials, so that the loosening kinetic energy of the material is improved, and the wet and sticky materials can be loosened well. At the same time, the kinetic energy of fine materials passing through the screen is also improved, so that the fine particle materials falling on the screen gap of the spring screen plate can pass through the screen more neatly, thereby improving the screening efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0028] Figure 1 It is a front view of a preferred embodiment of the composite screen of the present invention;

[0029] Figure 2 It is a left side view of a preferred embodiment of the composite screen of the present invention;

[0030] Figure 3 It is a structural schematic diagram of a preferred embodiment of a spring screen plate in a composite screen of the present invention;

[0031] Figure 4 It is a structural schematic diagram of a preferred embodiment of a ratchet wheel in a composite screen of the present invention;

[0032] Figure 5 yes Figure 1 A-direction view;

[0033] Figure 6 yes Figure 5 A partial enlarged view of B in the middle;

[0034] The markings of the components in the accompanying drawings are as follows: 1. Motor, 2. Drive shaft, 3. Circular screen, 4. Spring screen plate, 401. Spring rod, 402. Intermediate connecting piece, 5. Ratchet, 501. Arc gear teeth, 502. Wheel belly, 503. Shaft hole, 504. Keyway, 505. Tooth center circle, 6. Primary screen gap, 7. Secondary screen gap, 8. Feed inlet, 9. Discharge outlet, 10. Screening chamber. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] See also Figures 1 to 6 , the embodiment of the present invention includes:

[0037] A composite screen is located in a screening chamber 10. The screening chamber 10 has an inlet 8 on one side and a discharge port 9 on the other side. The screening chamber 10 is provided with an inclined composite screen.

[0038] In the present invention, the composite screen includes a circular screen plate 3, a ratchet 5, a drive shaft 2 and a spring screen plate 4. The circular screen plate 3 and the ratchet 5 are alternately connected in series on the drive shaft 2. The motor 1 drives the drive shaft 2 to operate. The circular screen plate 3 and the ratchet 5 are driven by the drive shaft 2 to perform circular motion along the rotation direction of the drive shaft 2.

[0039] The spring screen plate 4 comprises spring rods 401 on both sides and an intermediate connecting member 402 for fixing the spring rods 401 on both sides. The spring screen plate 4 is shaped like a double-sided comb as a whole.

[0040] The ratchet 5 is composed of a unidirectional arc surface gear tooth 501, a wheel belly 502, an axial hole 503 and a keyway 504. The ratchet 5 is installed on the driving shaft 2 through the axial hole 503 and the keyway 504. When the ratchet 5 rotates, it performs unidirectional intermittent motion in the inclined direction of the unidirectional arc surface gear tooth 501.

[0041] The spring screen plate 4 and the circular screen piece 3 are cross-arranged to form a composite screen surface. The cross-arrangement is that the spring rod 401 of the spring screen plate 4 is forked between the circular screen pieces 3, and the ends of the spring rod 401 on both sides of the spring screen plate 4 are tangent to the tooth center circle 505 of the ratchet 5.

[0042] In the present invention, a primary screen gap 6 of equal width is formed between adjacent circular screen plates 3 on the driving shaft 2. Materials smaller than the primary screen gap fall downward onto the spring screen plate 4, and materials larger than the primary screen gap 6 flow from the top surface of the circular screen plate 3 along the inclination angle of the composite screen to the discharge port, thereby realizing primary screening of the material.

[0043] Secondary screen gaps 7 of equal width are formed between the spring rods 401 on the composite screen surface and the circular screen plates 3 on both sides. The size of the secondary screen gaps 7 is matched according to the screening particle size.

[0044] The ratchet 5 rotates with the driving shaft 2, and the gradually changing circular arc tooth surface of the one-way arc gear tooth 501 lifts the spring rod 401, driving the spring screen plate 4 as a whole to perform a cyclical up and down displacement motion along the circular arc tooth surface. At this time, the material and the composite screen surface perform relative motion, and the movement direction of the material is perpendicular to the composite screen surface, so that the material obtains additional kinetic energy perpendicular to the composite screen surface.

[0045] In this way, as the composite screen surface vibrates, the loosening kinetic energy of the material is increased, so that the wet and sticky material can also be loosened well. At the same time, the kinetic energy of fine material passing through the screen is also increased, so that the fine particle material falling on the screen gap of the spring screen plate can pass through the screen more neatly, thereby improving the screening efficiency.

[0046] The composite screen of the present invention has a good screening effect for fine wet and sticky materials of coal, ore and similar properties, has low noise pollution and a compact structure, can solve the problems of easy clogging of the screen surface and low screening efficiency during the fine particle size classification of dry materials, overcomes the problems of large screen body, large dynamic load and high noise of the strong vibrating screen; and also overcomes the shortcomings of low discharge efficiency of residual materials in the screen cavity of the cross roller screen and incomplete discharge affecting the screening efficiency.

[0047] A method for screening materials with a composite screen, using the composite screen, comprises the following steps:

[0048] a) Primary screening material:

[0049] The material enters the screening chamber 10 from the feed port 8, and the circular screen 3 and the ratchet 5 perform circular motion under the action of the drive shaft 2.

[0050] Driven by its own weight and the circular screen, the material that is smaller than the distance between the adjacent circular screens 3, that is, smaller than the primary screen gap 6, falls down onto the spring screen plate 4.

[0051] The material larger than the primary screen gap 6 flows from the top surface of the circular screen plate 3 to the discharge port along the inclination angle of the composite screen;

[0052] b) Secondary screening material:

[0053] Driven by the circular screen plate 3, the materials on the spring screen plate 4 are smaller than the secondary screen gap 7, that is, the materials smaller than the interval between the spring rod 401 and the circular screen plates 3 on both sides fall under the composite screen surface, and the materials larger than the secondary screen gap 7 flow along the inclined screen surface formed by the spring screen plate 4 to the discharge port 9.

[0054] As the ratchet 5 rotates, the gradually changing arc surface of the one-way arc gear tooth 501 gradually lifts the spring rod 401 and then drops it. The spring rod 401 produces an up and down displacement movement based on the composite screen surface. Each time it passes through the arc tooth surface, an up and down displacement effect is generated. This cycle reciprocates to cause the composite screen surface to vibrate periodically. The vibration direction of the material is perpendicular to the plane where the composite screen surface is located, so that the material obtains additional kinetic energy perpendicular to the composite screen surface.

[0055] The beneficial effects of the composite screen and the screening method of the present invention are:

[0056] It has good screening effect for fine wet and sticky materials of coal, ore and similar properties, with low noise pollution and compact structure;

[0057] It can solve the problem of easy clogging of the screen surface and low screening efficiency during the fine particle size classification of dry materials. It inherits the advantages of the screen surface of the strong vibrating screen and the screen surface of the cross roller screen, overcomes the problems of large screen body, large dynamic load and high noise of the strong vibrating screen, and also overcomes the shortcomings of low discharge efficiency of residual materials in the screen cavity of the cross roller screen and incomplete discharge affecting the screening efficiency.

[0058] The material has additional kinetic energy perpendicular to the composite screen surface, the loosening kinetic energy of the material is improved, and the wet sticky material can be loosened well. At the same time, the kinetic energy of fine material passing through the screen is also improved, making the fine particle material falling on the screen gap of the spring screen plate pass through the screen more neatly, thereby improving the screening efficiency.

[0059] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A composite screen, located in a screening chamber, with an inlet on one side of the screening chamber and an outlet on the other side, characterized in that: The screening room is provided with an inclined composite screen, which includes a circular screen piece, a ratchet, a drive shaft and a spring screen plate. The circular screen piece and the ratchet are alternately connected in series on the drive shaft, and the spring screen plate and the circular screen piece are cross-arranged to form a composite screen surface. Driven by the drive shaft, the circular screen and the ratchet wheel move in a circular motion along the rotation direction of the drive shaft. The spring screen plate includes spring rods on both sides and an intermediate connecting piece for fixing the spring rods on both sides. The ratchet is composed of one-way arc-surface gear teeth, wheel belly, shaft hole and keyway. The ratchet is installed on the driving shaft through the shaft hole and keyway. When the ratchet rotates, it performs one-way intermittent motion in the inclined direction of the one-way arc-surface gear teeth. The spring rods of the spring screen plate are forked between the circular screen plates. The spring screen plate is arranged at an angle. The ends of the spring rods on both sides of the spring screen plate are tangent to the teeth center circle of the ratchet wheel to form a cross arrangement. The adjacent circular screens on the drive shaft form a primary screen gap of equal width to achieve primary screening of materials. The spring rods on the composite screen surface and the circular screen plates on both sides form a secondary screen gap of equal width. The size of the secondary screen gap is matched according to the screening particle size. The ratchet rotates with the driving shaft, and the gradually changing arc tooth surface of the one-way arc surface gear teeth lifts the spring rod, driving the spring screen plate as a whole to perform a cyclical up and down displacement movement along the arc tooth surface. The material and the composite screen surface move relative to each other, and the movement direction of the material is perpendicular to the composite screen surface.

2. A method for screening materials using a composite screen, characterized in that: The composite screen as claimed in claim 1 comprises the following steps: a) Primary screening material: The material enters the screening chamber from the feed port, and the circular screen and ratchet wheel move in a circular motion under the action of the drive shaft. Driven by its own weight and the circular screen, materials smaller than the distance between adjacent circular screens, that is, materials smaller than the first-level screen gap, fall down onto the spring screen plate. The material with a size larger than the first-level screen gap flows from the top surface of the circular screen piece to the discharge port along the inclination angle of the composite screen; b) Secondary screening material: Driven by the circular screen, the materials on the spring screen plate, which are smaller than the secondary screen gap, that is, smaller than the gap between the spring rod and the circular screen plates on both sides, fall under the composite screen surface, and the materials larger than the secondary screen gap flow to the discharge port along the inclined screen surface formed by the spring screen plate. As the ratchet rotates, the gradually changing arc surface of the one-way arc gear teeth gradually lifts the spring rod and then drops it. The spring rod moves up and down based on the composite screen surface. Each time it passes through the arc tooth surface, it produces an up and down displacement effect. This cycle repeats itself, causing the composite screen surface to vibrate periodically. The vibration direction of the material is perpendicular to the plane where the composite screen surface is located.

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