Adjustable screen gap device for sand mill

Abstract

This utility model relates to the field of sand mill screen technology, and in particular to an adjustable screen gap device for sand mills. It aims to solve the technical problems of fixed screen gaps, high replacement costs, and difficult cleaning after clogging in existing sand mills. The technical solution of this utility model includes: an internal support; a filter ring disposed on the internal support; an axial clamping assembly for applying a controllable axial clamping force to the filter ring; and multiple detachable gauge blocks. The gauge blocks are configured to be inserted between adjacent rings of the filter ring to limit and maintain a preset gap distance when the filter ring is axially clamped. This utility model allows for convenient adjustment of the screen gap to adapt to the grinding needs of materials of different specifications, reducing costs. Simultaneously, simply loosening the axial clamping assembly expands the gap of the filter ring, allowing clogged materials to be easily flushed out, greatly simplifying the cleaning process and improving the screen's reusability and equipment operating efficiency.

Description

Technical Field

[0001] This utility model relates to the field of sand mill screen technology, and in particular to an adjustable screen gap device for sand mills. Background Technology

[0002] A sand mill, also known as a bead mill, is a key piece of equipment for wet ultrafine grinding in industries such as chemicals, new energy, coatings, and inks. Its working principle involves using high-speed rotating grinding media (such as zirconia beads) to subject the material to intense impact, shearing, and friction, thereby achieving nanoscale particle refinement. During the grinding process, a screen device is needed to separate the ground slurry that meets the particle size requirements from the larger grinding media. Therefore, the performance of the screen directly affects the sand mill's output efficiency, product quality, and operational stability.

[0003] However, the conventional sand mill screens currently in widespread use have the following prominent problems:

[0004] First, the screen gap is fixed and lacks versatility. Conventional screens are usually made by welding or machining screen bars as a whole, and their screen gap is fixed at the factory and cannot be adjusted. In actual production, different products or different process stages of the same product may require different grinding fineness, which requires the use of screens with different gap sizes. For example, the screen gap required for coarse grinding and fine grinding stages may vary from 0.4mm to 0.2mm. To meet these needs, companies must purchase and stock a variety of screen components of different specifications. This not only increases the cost of equipment procurement and storage, but also requires downtime, disassembly, installation, and debugging every time a screen is replaced, which consumes a lot of time and affects production efficiency.

[0005] Secondly, the screen is prone to clogging and difficult to clean. During the high-intensity operation of the sand mill, some worn or broken zirconium beads, insufficiently dispersed material agglomerates, or impurities can easily wedge into and get stuck in the tiny gaps of the screen, causing clogging. Once clogging occurs, the slurry's throughput capacity drops sharply, leading to problems such as poor discharge and abnormally high pressure within the grinding chamber. Cleaning these blockages is quite difficult. Due to the very small screen gaps (e.g., 0.2mm), traditional cleaning methods, such as high-pressure water jet washing, ultrasonic cleaning machines, or even manual removal with fine needles, have very limited effectiveness, especially for extremely hard zirconium beads, where they are almost ineffective. Chemical methods such as acid soaking can corrode the screen material, affecting its service life. This cleaning challenge results in a significant amount of production time being wasted on ineffective maintenance, or causing severely clogged screens to fail prematurely, reducing screen reuse rates and further increasing operating costs.

[0006] To address the problem of screen clogging, several improvements have emerged in existing technologies. For example, Chinese utility model patent CN213700287U discloses a screen device for a sand mill that facilitates material discharge. This design employs a special wedge-shaped ring structure, characterized by the inner width of the ring being smaller than the outer width, resulting in a funnel-shaped filtration channel that is narrower inside and wider outside. The intention behind this design is that after the particulate material passes through the narrowest inner gap, the resistance encountered in subsequent channels is reduced, thereby decreasing the probability of particle adhesion and jamming, and ultimately improving discharge efficiency.

[0007] However, in-depth analysis of this existing technology reveals fundamental limitations in its solution. First, while the wedge structure may alleviate the tendency to clog to some extent, it cannot completely prevent clogging. Once a hard particle of just the right size or slightly larger enters the inlet, the screen will still become clogged. Second, and more critically, this solution does not address the two core pain points mentioned above: firstly, its screen gap remains fixed, determined by the size and assembly method of the wedge ring, lacking any adjustability, thus failing to meet the different screen precision requirements of various processes; secondly, once clogging occurs, the screen does not provide any effective active cleaning. Cleaning a clogged wedge ring screen is as difficult as cleaning a traditional screen because it does not offer a method to actively widen the screen gap to release the blockage.

[0008] Therefore, there is an urgent need in this field for a new sand mill screen technology that can not only enable convenient adjustment of the screen gap to adapt to diverse production needs, but also provide a simple and effective cleaning method to fundamentally solve the problem of cleaning after screen blockage, thereby comprehensively improving the operating efficiency of the sand mill and saving equipment costs. Utility Model Content

[0009] In order to solve the above-mentioned technical problems in the prior art, this utility model provides an adjustable screen gap device for sand mills.

[0010] To achieve the above objectives, the technical solution of this utility model is as follows:

[0011] The adjustable screen gap device for a sand mill includes: an internal support and a filter ring, wherein the filter ring is disposed on the outer peripheral surface of the internal support;

[0012] An axial clamping assembly configured to apply a controllable axial clamping force to the filter rings to tighten or loosen the ring spacing of the filter rings;

[0013] And a plurality of removable gauge blocks, wherein each of the gauge blocks is configured to be inserted between adjacent rings of the filter ring to define and maintain a preset screen gap when the filter ring is subjected to the axial clamping force.

[0014] Furthermore, the axial clamping assembly includes: an adjusting pressure plate, which is disposed at one end of the filter mesh ring and contacts the ring surface of the filter mesh ring;

[0015] And a gap adjusting plate, which is configured to apply an axial force to the adjusting pressure plate.

[0016] Furthermore, one end of the internal support is provided with a clearance adjustment external thread, and the clearance adjustment plate is a nut-shaped structure with an internal thread. The clearance adjustment plate is threadedly engaged with the clearance adjustment external thread through its internal thread.

[0017] Furthermore, the adjusting plate is disposed between the gap adjusting plate and the filter ring, and the adjusting plate is axially sliding relative to the internal support.

[0018] Furthermore, at least one gauge block positioning groove extending along its axial direction is provided on the outer peripheral surface of the internal support, and the gauge block positioning groove is distributed along the circumferential direction of the internal support.

[0019] Furthermore, the gauge block positioning groove contains multiple gauge blocks, the left and right sides of the gauge block positioning groove have a certain angle between them, the left and right sides of the gauge blocks have the same angle as the gauge block positioning groove, and the sidewall of the gauge block positioning groove restricts the gauge blocks from rotating circumferentially.

[0020] Furthermore, the device also includes at least one gauge block positioning pin, one end of which is tapered;

[0021] The gauge block positioning pin passes through a through hole on the gauge block along the axial direction to limit the radial displacement of the gauge block.

[0022] Furthermore, the device also includes a positioning pin pressure plate, which is detachably fixed to the internal support. The base of the internal support is provided with a tapered hole for engaging with the gauge block positioning pin in the axial direction to limit its movement and prevent it from coming out.

[0023] Furthermore, the filter ring is made of 316 stainless steel and is spirally wound around the outer circle of the inner support, which satisfies the following condition: when the axial clamping component is released, the axial clamping force applied to the filter ring is released, so that the gap between adjacent rings of the filter ring increases due to its own elasticity, thereby facilitating the removal of particles stuck in the gap.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The innovative feature of this utility model is the use of replaceable gauge blocks to set the screen gap in a sand mill. When the production process requires a change in screen precision, the operator does not need to replace the entire screen assembly; only a set of gauge blocks of different thicknesses needs to be replaced. This design greatly improves the versatility of the equipment, enabling a single sand mill to easily handle the grinding tasks of various materials, thereby reducing the investment costs for enterprises using screens of different specifications.

[0026] 2. The adjustable screen gap device for sand mills provided by this utility model cleverly utilizes the adjustability of the axial clamping component, making the screen easy to clean. When the screen becomes clogged, simply rotate and loosen the gap adjusting plate to release the axial clamping force on the filter rings. Under its own elasticity, the filter rings will automatically loosen, causing the screen gap to widen instantly. At this time, the previously stuck zirconium beads or material particles will loosen and can be cleaned by simple rinsing or blowing. The entire cleaning process is quick and convenient, fundamentally solving the problem of difficult traditional screen cleaning, shortening equipment maintenance downtime, and improving production efficiency and the repeated service life of the screen.

[0027] 3. The adjustable screen gap device for a sand mill provided by this utility model forms a stable and reliable support structure by placing gauge blocks in the positioning grooves of the internal support and locking them with positioning pins and pressure plates. This structure not only ensures the precise fixing of all gauge blocks but also provides radial support for the filter screen rings distributed along the axial direction. When the axial clamping assembly applies pressure, the filter screen rings are tightly pressed against these fixed gauge blocks, thereby ensuring that the entire screen has a highly consistent and precise gap in the length direction. This robust structure effectively resists the vibration and fluid impact force generated during the high-speed operation of the sand mill, prevents the screen bars from shaking and shifting, and ensures the stability of filtration accuracy and the durability of the screen. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the overall structure of the device.

[0030] Figure 2 This is a partial schematic diagram of the first method for installing gauge blocks for this device.

[0031] Figure 3 This is a partial schematic diagram of the second method for installing gauge blocks for this device.

[0032] Figure 4 This is a partial cross-sectional view of the device during installation.

[0033] The annotations in the attached figures are explained as follows:

[0034] 1-Filter mesh ring, 2-Adjusting pressure plate, 3-Internal support, 31-Gap adjustment external thread, 32-Gauge block positioning groove, 33-Positioning pin pressure plate internal thread, 34-Internal support base, 4-Gap adjustment plate, 5-Gauge block, 6-Gauge block positioning pin, 7-Positioning pin pressure plate. Detailed Implementation

[0035] The technical solution of this utility model will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of this utility model. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0036] It should be noted that, unless otherwise specifically stated, the relative arrangement and numerical expressions of the components and steps described in these embodiments should not be construed as limiting the scope of this utility model.

[0037] The following description of exemplary embodiments is merely illustrative and is not intended to limit the present invention or its application or use in any way. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail herein, but where applicable, such techniques, methods, and apparatus should be considered part of this specification.

[0038] This embodiment provides a device for adjusting the screen gap of a sand mill, such as... Figure 1 As shown, the device mainly consists of an internal support 3, a filter ring 1 wrapped around the outer periphery of the internal support 3, an axial clamping assembly for applying and adjusting axial pressure, and a set of gauge blocks 5 for setting the gap.

[0039] The internal support 3 is a cylindrical or tubular structure with an internal support base 34 at its lower end and an external thread 31 for gap adjustment at its upper end. A filter ring 1 is disposed on the outer circumferential surface of the internal support 3. The filter ring 1 is made of 316 stainless steel and is spirally wound around the outer circumference of the internal support 3. The overall shape of the filter ring is cylindrical or frustum-shaped. One end of the filter ring rests against the internal support base 34, while the other end contacts the axial clamping assembly.

[0040] In this embodiment, the axial clamping assembly specifically includes an adjusting pressure plate 2 and a gap adjusting plate 4. The adjusting pressure plate 2 is annular and detachably mounted on the internal support 3, located between the upper end face of the filter ring 1 and the gap adjusting plate 4. The adjusting pressure plate 2 can slide freely along the axial direction of the internal support 3. The gap adjusting plate 4 has an internal thread on its inner circle that mates with the gap adjusting external thread 31. By rotating the gap adjusting plate 4, it can move axially up and down on the gap adjusting external thread 31, thereby applying or releasing a controllable axial clamping force to the entire filter ring 1 through the adjusting pressure plate 2.

[0041] like Figures 1 to 4 As shown, a key feature of this invention is the use of different gauge blocks 5 to adjust the gap. Four gauge block positioning grooves 32 are evenly distributed along the axial circumference on the outer peripheral wall of the internal support 3. The gauge blocks 5 are block-shaped or sheet-shaped parts with precise thickness. During assembly, these gauge blocks 5 are sequentially inserted between adjacent rings of the filter mesh ring 1, embedding them into the gauge block positioning grooves 32. The sidewalls of the gauge block positioning grooves 32 effectively prevent the gauge blocks 5 from rotating or misaligning in the circumferential direction, ensuring accurate positioning.

[0042] To further secure gauge block 5 in place, this embodiment also includes a locking mechanism. For example... Figure 1 As shown, each gauge block 5 has a through-hole positioning hole. Gauge blocks 5 are sequentially inserted into the gaps of the filter ring 1 within the gauge block positioning groove 32 to set the gap of the filter ring 1. After all gauge blocks 5 are installed along a gauge block positioning groove 32, a long strip-shaped gauge block positioning pin 6 is passed through the positioning holes of all gauge blocks 5 from top to bottom. Finally, a positioning pin pressure plate 7 is threaded into the internal thread 33 of the positioning pin pressure plate at the top of the internal support 3 and fastened to the internal support 3. The positioning pin pressure plate 7 presses against the upper end of the gauge block positioning pin 6, thereby restricting the movement of the positioning pin 6 and reliably locking all gauge blocks 5 within the gauge block positioning groove 32. Finally, the gap adjusting plate 4 is tightened. The gap adjusting plate 4 pushes the adjusting pressure plate 2 downwards, and the adjusting pressure plate 2 presses against the filter ring 1. The filter ring 1 clamps the gauge blocks 5 to achieve the purpose of adjusting the gap. This locking system constructs a stable support system, ensuring that the screen maintains a uniform and stable gap even under severe working conditions.

[0043] The following is the operation process for adjusting the screen gap in this embodiment:

[0044] 1. First, remove the entire screen assembly from the sand mill.

[0045] 2. Rotate counterclockwise and remove the gap adjusting plate 4, then remove the adjusting pressure plate 2. At this time, the axial pressure on the filter ring 1 is completely released.

[0046] 3. Unscrew and remove the positioning pin pressure plate 7.

[0047] 4. Pull out all the gauge block positioning pins 6 from the top.

[0048] 5. At this point, gauge block 5 is no longer subject to any constraints and can be easily removed from the gaps in the filter ring 1 and the gauge block positioning groove 32.

[0049] 6. Based on the new process clearance requirements, select a new set of gauge blocks 5 with the target thickness. Insert these gauge blocks 5 one by one between adjacent rings of the filter screen ring 1, ensuring that they are all correctly seated in the gauge block positioning groove 32. Figure 2 and Figure 3 As shown, gauge blocks can be placed every few rings or between each ring, depending on design requirements, to achieve the necessary rigidity and accuracy. Specifically:

[0050] Option 1 (e.g.) Figure 2 For standard applications, a spaced arrangement can be used, for example, placing a gauge block 5 in the gap between every 5 filter coil layers. This method reduces the number of gauge blocks needed while ensuring basic support.

[0051] Option 2 (e.g.) Figure 3 To achieve a finer gap precision, gauge blocks 5 can be placed between adjacent layers of each filter ring 1.

[0052] 7. Insert the selected new gauge blocks 5 into the gauge block positioning slots 32, and ensure that they are all located in the gaps of the filter rings 1.

[0053] 8. Insert the gauge block positioning pin 6 back into the positioning hole of the gauge block 5, and tighten it with the positioning pin pressure plate 7.

[0054] 9. Finally, reinstall the adjusting pressure plate 2 and tighten the gap adjusting plate 4. During the tightening process, the gap adjusting plate 4 will push the adjusting pressure plate 2 downward, applying axial pressure to the entire filter ring 1, so that each ring is tightly clamped and pressed onto the measuring block 5, and the gap of the screen is adjusted.

[0055] Screen gap adjustment capability description:

[0056] To more clearly illustrate the adjustment capability of this utility model, a specific example is given below. Let the thickness of gauge block 5 be X, the thickness of a single turn of filter ring 1 be Y, the screen gap be Z, the effective height of the gap adjustment external thread 31 be M, the total number of turns of filter ring 1 be N, the thickness of gap adjustment plate 4 be Q, the thickness of adjustment pressure plate 2 be P, and the total height of filter ring 1 be H.

[0057] Assumptions: H = 500 mm, Y = 1 mm, M = 94 mm, Q = 8 mm.

[0058] When it is necessary to meet the market requirement that the screen gap Z in the fine grinding stage varies between 0.2mm and 0.4mm:

[0059] 1. Determine the number of turns: Based on the minimum gap Z = 0.2 mm, the required total number of turns N can be calculated.

[0060] From H = (N-1) × (Z+Y), we get 500 = (N-1) × (0.2+1). Solving for N, we get N ≈ 418 revolutions.

[0061] 2. Determine the adjustment stroke: The maximum adjustable stroke of the adjusting pressure plate 2 thickness P is equal to the effective thread height M minus the thickness Q of the clearance adjusting plate 4.

[0062] P = MQ = 94 - 8 = 86 mm.

[0063] 3. Maximum clearance: When the clearance adjusting plate 4 is at the highest point of the thread, the travel of the adjusting pressure plate 2 is at its maximum, and the maximum clearance Z that can be achieved is reached. max for:

[0064] From (H+P) / N=Z max +Y = (500 + 86) / 418 = Z max +1, solving for Z gives Z max ≈0.4mm.

[0065] Specifically, when the screen gap Z = 0.4 mm and the screen ring thickness Y = 1 mm,

[0066] Adjusting according to Option 1 yields a length X = 5.6 mm for gauge block 5.

[0067] Adjusting according to Option 2: the length of gauge block 5, X = 1.4 mm, can be obtained.

[0068] The calculations show that the device can achieve precise adjustment within the range of 0.2 mm to 0.4 mm.

[0069] The cleaning process for the screen is as follows:

[0070] 1. When it is found that the screen is clogged and the material is not flowing smoothly, remove the screen from the sand mill first.

[0071] 2. Without disassembling any other parts, simply rotate the gap adjusting plate 4 counterclockwise to move it upward along the thread 31, thereby releasing the pressure on the adjusting plate 2.

[0072] 3. Because the filter ring 1 is made of 316 stainless steel and is spirally wound around the outer circumference of the internal support, it inherently possesses a certain degree of plasticity and ductility. As the axial clamping force is released, the elastic filter ring 1 will automatically extend axially, significantly increasing the gap between the originally tightly contacting screen bars.

[0073] 4. In this state, the blockages such as broken zirconium beads and material agglomerates that were originally firmly stuck in the gap become loose due to the loss of the clamping force on both sides, and can be easily washed away by water flow and airflow.

[0074] 5. After cleaning, tighten the gap adjustment plate 4 clockwise to restore the pressure on the filter ring 1. The screen will then return to its precise working state and be ready for reuse.

[0075] In summary, this invention, through the ingenious combination of gauge block 5 and the axial clamping mechanism, successfully achieves two core functions: precisely adjustable screen spacing and quick and convenient cleaning. It fundamentally solves the pain points of existing technologies and provides an economical and reliable screen solution.

[0076] The above specific embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A device for adjusting the screen gap of a sand mill, characterized in that, include: An internal support (3) and a filter ring (1) are provided on the outer peripheral surface of the internal support (3); An axial clamping assembly is configured to apply a controllable axial clamping force to the filter ring (1) to tighten or loosen the ring spacing of the filter ring (1); And a plurality of removable gauge blocks (5), wherein each of the gauge blocks (5) is configured to be inserted between adjacent rings of the filter ring (1) to define and maintain a preset screen gap when the filter ring (1) is subjected to the axial clamping force.

2. The adjustable screen gap device for a sand mill according to claim 1, characterized in that: The axial clamping assembly includes: an adjusting pressure plate (2), which is disposed at one end of the filter mesh ring (1) and contacts the ring surface of the filter mesh ring (1); And a gap adjusting plate (4), which is configured to apply an axial force to the adjusting pressure plate (2).

3. The adjustable screen gap device for a sand mill according to claim 2, characterized in that: One end of the internal support (3) is provided with a gap adjustment external thread (31), and the gap adjustment plate (4) is a nut-shaped structure with an internal thread. The gap adjustment plate (4) is threadedly engaged with the gap adjustment external thread (31) through its internal thread.

4. The adjustable screen gap device for a sand mill according to claim 3, characterized in that: The adjusting plate (2) is disposed between the gap adjusting plate (4) and the filter ring (1), and the adjusting plate (2) can slide axially relative to the internal support (3).

5. The adjustable screen gap device for a sand mill according to claim 1, characterized in that: The outer peripheral surface of the internal support (3) is provided with at least one gauge block positioning groove (32) extending along its axial direction, and the gauge block positioning groove (32) is distributed along the circumferential direction of the internal support (3).

6. The adjustable screen gap device for a sand mill according to claim 5, characterized in that: The gauge block positioning groove (32) contains multiple gauge blocks (5). The left and right sides of the gauge block positioning groove (32) have a certain angle between them. The left and right sides of the gauge block (5) have the same angle as the gauge block positioning groove (32). The side wall of the gauge block positioning groove (32) restricts the circumferential rotation of the gauge block (5).

7. The adjustable screen gap device for a sand mill according to claim 6, characterized in that: The device also includes at least one gauge block positioning pin (6), one end of which is tapered; The gauge block positioning pin (6) passes through the through hole provided on the gauge block (5) along the axial direction to limit the radial displacement of the gauge block (5).

8. The adjustable screen gap device for a sand mill according to claim 7, characterized in that: The device also includes a positioning pin plate (7), which is detachably fixed on the internal bracket (3). The base of the internal bracket (3) is provided with a tapered hole for limiting the positioning pin (6) in the axial direction to prevent it from coming out.

9. The adjustable screen gap device for a sand mill according to claim 1, characterized in that: The filter mesh (1) is made of 316 stainless steel and is spirally wrapped around the outer circle of the inner support (3).

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