Carbon-glass mixed composite material magnetic separation cylinder, magnetic separator and preparation method

Abstract

The invention discloses a carbon-glass mixed composite material magnetic separation cylinder, a magnetic separator and a preparation method. The carbon-glass mixed composite material magnetic separation cylinder comprises a winding cylinder body and a metal lining, the winding cylinder is formed by alternately laying a carbon fiber layer and two glass fiber layers, the carbon fiber layer is formed by vertically and annularly winding carbon fibers, the glass fiber layers are formed by obliquely and annularly winding glass fibers, and the oblique and annular winding directions of the glass fibers of the two glass fiber layers are opposite; the metal lining is embedded in a connecting hole position at the end part of the winding cylinder body; by constructing the carbon fiber angle laying layers of the parallel magnetic induction lines and the glass fiber angle laying layers of the non-parallel magnetic induction lines, the overall rigidity of the magnetic separation cylinder is improved, and the cylinder body temperature rise caused by induction eddy current is avoided, so that the wall thickness of the magnetic separation cylinder is reduced, the magnetic gap is reduced, and the service life is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of improvement of components of magnetic separators, and particularly relates to a carbon and glass fiber composite magnetic separation cylinder, a magnetic separator and a preparation method thereof. Background Art

[0002] The statements herein only provide background art related to the present invention and do not necessarily constitute prior art.

[0003] Current magnetic separator equipment is gradually developing towards high power, strong magnetic field and high linear speed with the industrial demand. For its magnetic separation cylinder components, thinner wall thickness is required to reduce the magnetic gap, improve the magnetic attraction, and reduce the electrical conductivity of the material and the eddy current. The current magnetic separation cylinder is mainly made of non-magnetic stainless steel material, which has a relatively high cutting rate of magnetic field magnetic force lines, resulting in the generation of induced eddy current in the stainless steel magnetic separation cylinder, which will rapidly increase the temperature of the magnetic separation cylinder, affect the magnetic field strength, and reduce the service life of the equipment. The current stainless steel magnetic separation cylinder severely restricts the development of magnetic separator equipment towards strong magnetic and high efficiency.

[0004] In the prior art, in order to achieve a thinner wall thickness of the magnetic separation cylinder, it is proposed to use non-metallic composite materials to prepare the magnetic separation cylinder. For example, carbon fiber composite materials are used. The modulus and strength of carbon fiber are relatively high, and an ultra-thin wall thickness can be achieved, significantly reducing the magnetic gap. However, since carbon fiber is a good conductor, although its electrical conductivity is lower than that of stainless steel, it will still cut the magnetic induction lines to generate eddy current, and there is still a temperature rise problem during long-term operation. In addition, due to the significant anisotropy of carbon fiber, the axial modulus of the pure circumferential ply is insufficient, and diagonal plies need to be added. However, the diagonal carbon fiber will cut the magnetic induction lines, exacerbating the eddy current, and in the case of long-term high temperature, the magnetic material will gradually demagnetize, and ultimately the expected separation effect cannot be achieved. Summary of the Invention

[0005] The purpose of the present invention is to provide a carbon and glass fiber composite magnetic separation cylinder, a magnetic separator and a preparation method thereof. By constructing a carbon fiber angle ply parallel to the magnetic induction lines and a glass fiber angle ply non-parallel to the magnetic induction lines, the overall rigidity of the magnetic separation cylinder is improved, and the temperature rise of the cylinder body caused by the generation of induced eddy current is avoided, so as to achieve the reduction of the wall thickness of the magnetic separation cylinder, the reduction of the magnetic gap, and the improvement of the service life.

[0006] In order to achieve the above purpose, the present invention is realized through the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a carbon and glass fiber composite magnetic separation cylinder, including a winding cylinder and a metal bushing; the winding cylinder is composed of alternating layers of one layer of carbon fiber layer and two layers of glass fiber layer. The carbon fiber layer is wound vertically and circumferentially with carbon fiber, and the glass fiber layer is wound obliquely and annularly with glass fiber. The glass fiber oblique circumferential winding directions of the two glass fiber layers are opposite; the metal bushing is embedded in the connection hole positions at the ends of the winding cylinder.

[0008] As a further technical solution, the winding direction of the glass fiber forms an angle less than 45° with the axis of the winding cylinder.

[0009] As a further technical solution, the wall thickness of the winding cylinder is 2 - 4 mm, and the overall conductivity of the winding cylinder does not exceed 1 / 10000 of that of stainless steel.

[0010] As a further technical solution, the volume content of the carbon fiber layer accounts for 30% - 50% of the total of the winding cylinder, and the tensile modulus of the carbon fiber layer ≥ 120 Gpa.

[0011] As a further technical solution, the outermost layer of the winding cylinder is a glass fiber layer, and the innermost layer is a carbon fiber layer.

[0012] As a further technical solution, the winding directions of two adjacent glass fiber layers adjacent to the carbon fiber layer are the same.

[0013] As a further technical solution, the metal bushing is connected to the winding cylinder through an adhesive, and the material of the metal bushing is stainless steel.

[0014] In a second aspect, an embodiment of the present invention provides a magnetic separator, including the carbon - glass hybrid composite magnetic separation cylinder described in the first aspect.

[0015] In a third aspect, an embodiment of the present invention provides a method for preparing a carbon - glass hybrid composite magnetic separation cylinder, including the following steps:

[0016] Use carbon fiber prepreg to wind around the core mold in a vertical circumferential direction to form a carbon fiber layer;

[0017] Use glass fiber prepreg to wind around the carbon fiber layer in an inclined circumferential direction to form a first glass fiber layer, and use glass fiber prepreg to wind around the first glass fiber layer in an inclined circumferential direction to form a second glass fiber layer, and the winding inclination directions of the first glass fiber layer and the second glass fiber layer are opposite;

[0018] Repeat the above steps to alternately wind multiple layers of carbon fiber layers and multiple layers of glass fiber layers;

[0019] After curing and forming the wound winding cylinder, demold it to obtain an integral winding cylinder;

[0020] Open connection holes at the ends of the winding cylinder, and use an adhesive to bond the metal bushing at the connection hole positions.

[0021] As a further technical solution, the carbon fiber prepreg uses carbon fiber filaments impregnated with resin, and the glass fiber prepreg uses glass fiber filaments impregnated with resin.

[0022] The beneficial effects of the above - mentioned embodiments of the present invention are as follows:

[0023] The present invention adopts a composite material system reinforced by a mixture of carbon fiber and glass fiber, and achieves a breakthrough improvement in material properties through the synergistic effect of the two fibers. Carbon fiber has extremely high tensile modulus and strength, providing good circumferential rigidity for the magnetic separation drum; while glass fiber has relatively low modulus, but it has obvious cost advantages and excellent insulation performance. By precisely controlling the volume ratio of the two fibers, the overall modulus of the composite material is close to that of stainless steel. This combination of high-performance materials enables the wall thickness of the magnetic separation drum to be reduced from more than 4 mm of traditional stainless steel to 2 - 4 mm, achieving high rigidity, thin wall thickness and lightweight of the magnetic separation drum.

[0024] In the present invention, the carbon fiber layer adopts an accurate 90° circumferential laying. The circumferential arrangement makes the direction of the carbon fiber completely parallel to the magnetic field direction of the magnetic separator (entering and exiting the cylinder body at nearly 90° perpendicular), avoiding the generation of eddy currents caused by conductors cutting magnetic induction lines. The glass fiber layer adopts an alternating diagonal laying, which not only ensures the axial stiffness, but also completely eliminates the generation of eddy currents due to its insulation characteristics, solving the technical problem of overheating and demagnetization of traditional magnetic separation drums.

[0025] The material system of the present invention creates extremely low eddy current loss characteristics. The conductivity of the carbon fiber composite material is only 1 / 10000 of that of stainless steel; while glass fiber is completely insulated. Through the laying design of carbon fiber in the direction parallel to the magnetic field at 90°, it hardly cuts the magnetic induction lines; although the glass fiber cuts the magnetic induction lines when laid diagonally, no current is generated due to its insulation characteristics. This combination greatly reduces the equivalent conductivity of the overall structure, avoids the generation of eddy currents, and the characteristic of almost zero temperature rise enables the permanent magnet to avoid the risk of high-temperature demagnetization and improves the service life of the equipment.

[0026] The present invention adopts a fiber winding process to achieve the integral molding of the magnetic separation drum. The angle control is accurate, there are no metal welds, which improves the coherence of the structural mechanical properties and avoids welding stress and defects.

[0027] Through the collaborative innovation of materials and structures, the present invention achieves significant lightweight benefits. The overall weight is reduced by more than 40% compared with the existing metal magnetic separation drums, which can effectively reduce the overall operating cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0029] Figure 1 is the front view of the carbon - glass hybrid composite magnetic separation drum of the present invention;

[0030] Figure 2 is the side view of the carbon - glass hybrid composite magnetic separation drum of the present invention;

[0031] Figure 3 is Figure 1 a partial enlarged schematic view at position A in

[0032] Figure 4 a schematic diagram of the magnetic field strength distribution of an existing permanent magnet type magnetic separator.

[0033] The schematic diagram is only for illustration purposes;

[0034] wherein, 1, winding cylinder; 101, carbon fiber layer; 102, first fiberglass layer; 102, second fiberglass layer; 2, metal bushing. Specific embodiments

[0035] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0036] Example 1

[0037] As Figure 4 shown, the arc-shaped permanent magnets are coaxially installed in the magnetic separation cylinder. The magnetic field distribution of the arc-shaped permanent magnets is as shown by the arc-shaped lines in Figure 4 . When the magnetic separation cylinder rotates during the operation of the magnetic separator and the arc-shaped permanent magnets remain stationary, when the carbon fiber of the magnetic separation cylinder adopts a pure circumferential laying, the axial modulus of the magnetic separation cylinder is insufficient. If an oblique laying is adopted, the oblique carbon fiber will cut the magnetic induction lines, exacerbating the eddy current.

[0038] To solve the above problems, in a typical embodiment of the present invention, as Figures 1-3 shown, a carbon fiber and fiberglass composite magnetic separation cylinder is provided, including a winding cylinder 1 and a metal bushing 2; the winding cylinder is composed of an alternating laying of one layer of carbon fiber layer and two layers of fiberglass layers. The carbon fiber layer is formed by vertically circumferentially winding carbon fiber, and the fiberglass layer is formed by obliquely circumferentially winding fiberglass. The obliquely circumferential winding directions of the fiberglass of the two fiberglass layers are opposite; the metal bushing is embedded in the connection hole positions at the ends of the winding cylinder.

[0039] In this embodiment, a laminated structure with alternating carbon fiber and glass fiber is proposed. The fiber direction of the carbon fiber layer is circumferential (i.e., the angle with the axis of the wound cylinder is 90°), which improves the rigidity of the cylinder cross-section and is parallel to the magnetic field direction, avoiding the generation of eddy currents. The glass fiber layer is wound in an inclined circumferential direction, which can provide axial rigidity, and glass fiber is an insulator and will not generate eddy sense current. In addition, the carbon fiber bears the circumferential load to ensure the radial rigidity under thin walls; the glass fiber provides axial bending stiffness through laminations with opposite inclined directions to prevent barrel-shaped deformation during high-speed rotation. This alternating laminated structure makes the overall modulus close to that of stainless steel, but the weight is reduced by more than 60%.

[0040] In this embodiment, the angle between the winding direction of the glass fiber and the axis of the wound cylinder is less than 45°. The inclined lamination angle of the glass fiber can balance the axial and circumferential moduli and avoid the problem of insufficient axial rigidity of a pure circumferential lamination (90°). The glass fiber winding layer mainly provides axial stiffness. When the fiber angle is 45°, the force components of the fiber along the axial and radial directions are equal. The smaller the angle, the greater the axial component force, which is more advantageous for improving the axial stiffness.

[0041] In this embodiment, the wall thickness of the wound cylinder is 2 - 4 mm, and the overall conductivity of the wound cylinder does not exceed 1 / 10000 of that of stainless steel. The conductivity of the carbon fiber composite material is only 1 / 10000 of that of stainless steel, and the glass fiber composite material is an insulator, which can greatly reduce the eddy current intensity, avoid the resulting temperature rise, and effectively improve the service life. In addition, the overall weight of the wound cylinder is reduced by more than 40% compared with the existing metal magnetic separation cylinder, which can effectively reduce the comprehensive operation cost.

[0042] In this embodiment, the volume content of the carbon fiber layer accounts for 30% - 50% of the total of the wound cylinder, and the tensile modulus of the carbon fiber layer ≥ 120 GPa. When the carbon fiber content is less than 30%, the circumferential modulus is insufficient and cannot meet the requirements of high rigidity under thin walls. When the carbon fiber content is greater than 50%, the cost increases sharply, and the proportion of the inclined glass fiber layer is insufficient, resulting in a decrease in axial rigidity. Since the density of the composite material cylinder is only about 1 / 4 of the density of stainless steel, when the volume content of the carbon fiber layer is 30% - 50%, the radial deformation of the circumferential cylinder is close to that of the stainless steel cylinder. In addition, the single-layer thickness of the carbon fiber is 0.125 mm, and that of the glass fiber is 0.15 mm. Calculated by volume ratio, each 1 mm wall thickness contains 2 layers of carbon fiber + 3 layers of glass fiber to ensure uniform distribution of interlayer stress.

[0043] In this embodiment, the outermost layer of the wound cylinder is a glass fiber layer, and the innermost layer is a carbon fiber layer. The outer glass fiber layer can be coated with a wear-resistant coating (such as polyurethane) to avoid wear by the pulp; the inner carbon fiber layer is close to the permanent magnet roller to reduce hysteresis loss. During the winding process, the inner carbon fiber layer is wound first to ensure close fitting with the core mold; the outer glass fiber layer is wound later to avoid resin overflow.

[0044] In this embodiment, the winding directions of the two glass fiber layers adjacent to the carbon fiber layer are the same. If the winding inclination directions of the two glass fiber layers adjacent to the carbon fiber layer are opposite, shear cracks are likely to occur between the layers; the same-direction winding makes the interlayer stress coherent and can improve the fatigue life of the wound cylinder.

[0045] In this embodiment, the metal bushing is connected to the wound cylinder through an adhesive, and the material of the metal bushing is stainless steel. Alternatively, the metal bushing can also be embedded at the end of the wound cylinder in a pre-buried manner during the winding process of the cylinder. The metal bushing is an existing structure, such as a connecting flange.

[0046] The carbon-glass hybrid composite magnetic separator cylinder provided in this embodiment improves the overall rigidity of the magnetic separator cylinder by constructing a carbon fiber angle ply parallel to the magnetic induction lines and a glass fiber angle ply non-parallel to the magnetic induction lines, avoiding the temperature rise of the cylinder caused by the generation of induced eddy currents, thereby realizing the reduction of the wall thickness of the magnetic separator cylinder, the reduction of the magnetic gap, and the improvement of the service life. It solves the problem of frequent overheating of the equipment caused by the high speed of high-power magnetic separators and improves the power limit of the equipment. The present invention can effectively improve the service life and production efficiency of products and reduce costs.

[0047] In addition, fiber-reinforced composites have the characteristics of light weight and high strength, and can replace stainless steel materials as the materials of magnetic separator cylinders, reducing the wall thickness and the magnetic gap. The strength and modulus of carbon fiber composites are higher than those of glass fiber composites. Using carbon fiber composites can make the wall thickness of the magnetic separator cylinder thinner. However, since carbon fiber is a conductor, cutting the magnetic force lines will generate induced current, while glass fiber composites, as insulators, will not generate induced eddy currents when cutting the magnetic induction lines. The two fibers are mixed and used in a matching magnetic field angle, which can more efficiently reduce the wall thickness and avoid the generation of induced eddy currents.

[0048] Embodiment 2

[0049] In a typical implementation manner of the present invention, a magnetic separator is provided, including the carbon-glass hybrid composite magnetic separator cylinder described in Embodiment 1.

[0050] Embodiment 3

[0051] In a typical implementation manner of the present invention, a preparation method of a carbon-glass hybrid composite magnetic separator cylinder is provided, including the following steps:

[0052] Use carbon fiber prepreg to wind vertically circumferentially on the core mold to form a carbon fiber layer 101;

[0053] The glass fiber prepreg is wound along the inclined circumferential direction on the carbon fiber layer to form the first glass fiber layer 102. The glass fiber prepreg is wound along the inclined circumferential direction on the first glass fiber layer to form the second glass fiber layer 103. The winding inclined directions of the first glass fiber layer and the second glass fiber layer are opposite.

[0054] Repeat the above steps to alternately wind multiple layers of carbon fiber layers and multiple layers of glass fiber layers.

[0055] After the wound winding cylinder is cured and formed, it is demolded to obtain an integrated winding cylinder.

[0056] Connecting holes are opened at the ends of the winding cylinder, and metal bushings are bonded at the positions of the connecting holes by using adhesives.

[0057] Furthermore, the carbon fiber prepreg uses carbon fiber filaments impregnated with resin, and the glass fiber prepreg uses glass fiber filaments impregnated with resin.

[0058] Specifically, the magnetic field distribution of the permanent magnet roll type magnetic separator is as Figure 4 shown. The magnetic induction lines enter and exit the magnetic separation cylinder at an angle close to 90°. When the magnetic separation cylinder rotates, the conductor fibers that are not at 90° along the axial direction will cut the magnetic induction lines and generate induced eddy currents.

[0059] To improve the rigidity of the magnetic separation cylinder, reduce the magnetic gap, and solve the problem of induced eddy currents, the winding cylinder is formed by continuous winding. The layup is as Figures 1-3 shown. The first layer is wound with carbon fiber in the 90° direction to improve the radial modulus of the cylinder. At the same time, when the carbon fiber in the 90° direction rotates, it is parallel to the magnetic field direction and no induced eddy currents will be generated. The second and third layers are wound with glass fiber, and the winding angle directions are opposite, and the angle is less than 45 degrees to improve the axial modulus of the cylinder. Since the glass fiber is an insulator, no induced eddy currents will be generated. According to the mechanical property requirements, the subsequent layup is cycled and alternated according to the layup angles of the first three layers. Since almost no induced eddy currents are generated in the entire layup structure, the temperature rise rate of the cylinder can be ignored.

[0060] The winding cylinder is composed of a carbon and glass mixed fiber material as the reinforcement and a thermosetting resin as the matrix. The weight of the material per unit volume is 1 / 4 of that of stainless steel, the modulus is equivalent to that of stainless steel, and the strength is 3 times that of stainless steel. The wall thickness of the magnetic separation cylinder can be reduced by 1 / 2, and the minimum can reach a wall thickness of 2 mm. The magnetic gap can be reduced by half, and the magnetic field strength is increased by 1 / 4.

[0061] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A carbon-glass hybrid composite magnetic separation cylinder, characterized in that: It comprises a winding cylinder and a metal bushing; the winding cylinder is formed by alternating a layer of carbon fiber and two layers of glass fiber, the carbon fiber layer is formed by vertically circumferentially winding carbon fibers, the glass fiber layer is formed by obliquely annularly winding glass fibers, and the oblique annular winding directions of the glass fibers of the two glass fiber layers are opposite; the metal bushing is embedded in the connecting hole at the end of the winding cylinder.

2. The carbon-glass hybrid composite material magnetic separator according to claim 1, characterized in that: The angle between the winding direction of the glass fiber and the axis of the winding cylinder is less than 45°.

3. The carbon-glass hybrid composite magnetic separator according to claim 1, characterized in that: The wall thickness of the winding cylinder is 2-4 mm, and the overall electrical conductivity of the winding cylinder does not exceed 1 / 10000 of that of stainless steel.

4. The carbon-glass hybrid composite material magnetic separator according to claim 1, characterized in that: The volume content of the carbon fiber layer accounts for 30%-50% of the total winding cylinder, and the tensile modulus of the carbon fiber layer is ≥120Gpa.

5. The carbon-glass hybrid composite material magnetic separator according to claim 1, characterized in that: The outermost layer of the winding cylinder is a glass fiber layer, and the innermost layer is a carbon fiber layer.

6. The carbon-glass hybrid composite material magnetic separator according to claim 1, characterized in that: The winding directions of the two glass fiber layers adjacent to the carbon fiber layer are the same.

7. The carbon-glass hybrid composite material magnetic separator according to claim 1, characterized in that: The metal bushing is connected to the winding cylinder through an adhesive, and the material of the metal bushing is stainless steel.

8. A magnetic separator, characterized in that: It comprises a carbon-glass hybrid composite material magnetic separation cylinder as described in any one of claims 1 to 7.

9. A method for preparing a carbon-glass hybrid composite magnetic separation cylinder according to any one of claims 1 to 7, characterized in that: The following steps are involved: Carbon fiber prepreg is wound vertically on the core mold to form a carbon fiber layer; A glass fiber prepreg is wound on the carbon fiber layer in an inclined circumferential direction to form a first glass fiber layer, and a glass fiber prepreg is wound on the first glass fiber layer in an inclined circumferential direction to form a second glass fiber layer, wherein the winding inclination directions of the first glass fiber layer and the second glass fiber layer are opposite; Repeat the above steps, alternately winding multiple carbon fiber layers and multiple glass fiber layers; The wound winding cylinder is solidified and then demoulded to obtain an integrated winding cylinder; A connecting hole is opened at the end of the winding cylinder, and a metal bushing is bonded to the connecting hole with an adhesive.

10. The method for preparing the carbon-glass hybrid composite material magnetic separation cylinder according to claim 9, characterized in that: The carbon fiber prepreg is made of carbon fiber filaments impregnated with resin, and the glass fiber prepreg is made of glass fiber filaments impregnated with resin.

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