A slide plate type filter screen changing device with an external flexible sealing structure

Abstract

This invention discloses a slide-type filter screen changing device with an external flexible sealing structure, belonging to the field of polymer melt filtration. The invention features an external flexible sealing structure whose sealing principle is as follows: the elastic force generated by the compression of the disc spring by the sliding plate sealing force adjusting bolt serves as the sealing force between the slide plate and the sealing ring. The sealing force is automatically adjusted, achieving a gapless and natural fit between the sealing ring and the slide plate, ensuring a good sealing effect with zero material leakage and smooth, unobstructed movement of the slide plate during screen changing. The sealing force can be adjusted as needed to meet the filtration sealing requirements of various materials. Automatic sealing compensation is achieved after the sealing ring wears, greatly improving sealing durability and extending sealing time, maintaining a good sealing effect for a long time without leakage. The flow channel and sealing surface are always dynamically fitted without dead angles, preventing material melt from stagnating at the sealing interface and effectively avoiding contamination caused by long-term material retention in the stagnant area.

Description

Technical Field

[0001] This invention belongs to the technical field of material melt filtration before pelleting of virgin polymer raw materials, during the production of polymer products, and during recycling and reuse. More specifically, it is a slide-type filter screen replacement device with an external flexible sealing structure. Background Technology

[0002] Filtration and screen changing devices are required in large-scale polymer polymerization pelletizing equipment and in the production or recycling of certain polymer products, primarily to filter out impurities in a timely manner. One common type of filtration and screen changing device is the slide plate type. Current slide plate type filtration and screen changing devices generally employ two sealing structures: the first is a rigid seal with a gap, where a precise height difference is formed between the slide plate and the gasket, which is also the value at which the slide plate can slide back and forth. This is typically designed to be 0.03–0.05 mm—because the overflow value of polymer is ≤0.05 mm, if the gap is too small, the slide plate is easily damaged or jammed; if the gap is too large, polymer melt leakage will occur. Furthermore, even if the initial sealing gap is optimal, leakage will still occur due to wear over time. The second type is the built-in flexible sealing structure, which can effectively solve the leakage defects of rigid seals. It has been widely used in sliding plate filter screen changing devices. For example, two of our company's utility model patents—patent number ZL201921483151.1, entitled "A non-stop screen changing device for polystyrene carbon dioxide extrusion foaming," and patent number ZL202022690154.1, entitled "Ultra-large screen changing device integrating filtration and mixing"—include the use of a built-in flexible sealing structure as one of their core technologies. While the built-in flexible sealing structure demonstrates its unique advantages, it has also gradually revealed certain limitations during use—namely, the long-term retention of material. This is because the dynamic sealing ring in the built-in flexible sealing structure is floated by a cylindrical spring. The purpose is to allow the molten material to enter the space formed between the dynamic sealing ring and the inlet plate. The back pressure of the molten material pushes or squeezes the dynamic sealing ring to create a sealing force between it and the sliding plate. Therefore, long-term material retention occurs in the space between the dynamic sealing ring and the inlet plate, as well as in the cavity housing the spring. Although improvements were made in subsequent utility model patents (patent number 202220498585.4), this flexible sealing structure still has some side effects on certain special materials (such as corrosive, easily degraded or even carbonized materials, or materials with extremely poor flowability). These materials are difficult to displace and can cause serious effects such as corrosion or carbonization in the retention area, leading to the inability of the screen changing device to function properly. In summary, the sealing in the slide-type filter screen changing device, whether using a rigid seal with gaps or an internal flexible seal structure, has obvious shortcomings. Therefore, it is necessary to iteratively upgrade the sealing structure of the slide-type filter screen changing device to design a slide-type filter and screen changing device that can maintain a good sealing effect for a long time without leakage, and can also avoid the adverse effects of materials remaining in the retention area for a long time. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of the existing technology by providing a sliding plate filter screen changing device with an external flexible sealing structure. This invention enables automatic and on-demand adjustment of the sealing force, meeting the filtration and sealing requirements of various materials. It achieves a seamless, natural fit between the sealing ring and the sliding plate, ensuring a zero-leakage sealing effect while guaranteeing smooth sliding plate movement without jamming during screen changing. Furthermore, this invention enables automatic sealing compensation, significantly improving sealing durability and extending sealing effectiveness, maintaining a good sealing effect for extended periods without leakage. It also prevents molten material from accumulating at the sealing interface, effectively avoiding contamination caused by prolonged material retention in the retention area. Therefore, this invention offers advantages such as automatic sealing, adjustable sealing force, zero leakage, anti-jamming, automatic sealing compensation, good sealing durability, long sealing effectiveness, no material retention, no contamination, strong versatility, wide applicability, long service life, easy online screen changing, and convenient use.

[0004] The objective of this invention can be achieved through the following technical measures: This invention discloses a slide-type filter screen replacement device with an external flexible sealing structure, comprising a slide base and a hydraulic cylinder respectively fixed at the front and rear ends of a U-shaped frame (the U-shaped frame provides an installation and support foundation for the slide base and hydraulic cylinder; the hydraulic cylinder provides driving power for the slide; the slide base provides a guiding and support foundation for the slide, and also provides installation space for sealing components such as inlet sealing ring, outlet sealing ring, and slide sealing force adjusting bolts), a slide plate that runs through the slide base along its length and can slide back and forth under the drive of the hydraulic cylinder (when the filter screen needs to be replaced, it can be quickly pulled backward (Embodiment 1) or pushed forward (Embodiment 2) by the drive of the hydraulic cylinder to move the slide plate, so that the positions of the two filter units are interchanged and the dirty filter screen can be removed). One filter unit is simply fitted with a clean filter screen for later use, while the other filter unit is located at the filtration station for normal filtration operations. Two sets of filter units, each composed of a filter screen and a perforated plate, are installed at intervals along the longitudinal centerline of the slide plate (one filter unit is at the filtration station, and the other is at the screen replacement station). The slide plate base is a composite base formed by interlocking the inlet plate and outlet plate in the thickness direction and fastening them together with a slide plate sealing force adjusting bolt penetrating the thickness direction, along with matching nuts, nut check keys, and disc springs. (The sealing principle of this invention is—the elastic force generated by compressing the disc spring through the slide plate sealing force adjusting bolt serves as the sealing force between the slide plate and the inlet sealing ring, and between the slide plate and the outlet sealing ring; the sealing...) The sealing force can be automatically adjusted to achieve a gapless, natural fit between the sealing ring and the slide plate, ensuring both a leak-free seal and smooth, unobstructed sliding of the slide plate during screen changing. The sealing force can be adjusted as needed to meet the filtration sealing requirements of various materials. Automatic seal compensation is achieved after the sealing ring wears, greatly improving seal durability and extending sealing time, maintaining a good seal for a long time without leakage. The inlet plate has a symmetrical upper cavity surface with convex ends and a continuously stepped, recessed middle section, while the outlet plate has a symmetrical lower cavity surface with concave ends and a stepped groove with two convex and one concave middle section. The upper and lower cavity surfaces of the stepped groove interlock to form a three-part... The stepped cavity provides installation space for the inlet sealing ring, slide plate, and outlet sealing ring. The middle section of the three-step stepped cavity sequentially houses the inlet sealing ring, slide plate, and outlet sealing ring from top to bottom. The upper cavity of the two end sections of the three-step stepped cavity serves as an adjustment gap for the thickness of the inlet sealing ring (providing a reserved gap for automatic sealing compensation after the inlet sealing ring wears out). The lower cavity of the two end sections of the three-step stepped cavity serves as an adjustment gap for the thickness of the outlet sealing ring (providing a reserved gap for automatic sealing compensation after the outlet sealing ring wears out). A thickness adjustment guarantee gap is reserved between the protruding interlocking surface section at the end of the inlet plate and the recessed interlocking surface section at the end of the outlet plate (providing a reserved gap for automatic sealing compensation after the inlet and outlet sealing rings wear out).The left and right end faces of the slide plate are respectively in contact with the slide width adjusting bolts that protrude through the end of the inlet plate along the width direction (the slide width adjusting bolts are used to adjust the position of the slide plate in the width direction and serve as sliding guides).

[0005] In this invention, the narrowest gap of the inlet sealing ring thickness adjustment gap is greater than the maximum wear thickness of the inlet sealing ring (ensuring no motion interference occurs during automatic sealing compensation after the inlet sealing ring wears out); the narrowest gap of the outlet sealing ring thickness adjustment gap is greater than the maximum wear thickness of the outlet sealing ring (ensuring no motion interference occurs during automatic sealing compensation after the outlet sealing ring wears out); the thickness adjustment ensures that the gap is not less than the sum of the maximum wear thickness of the inlet sealing ring and the maximum wear thickness of the outlet sealing ring (ensuring no motion interference occurs during automatic sealing compensation after the inlet and outlet sealing rings wear out).

[0006] In this invention, the disc spring is embedded in the mounting groove opened on the outer surface of the inlet plate, and the elastic extension of the disc spring is greater than the sum of the maximum wear thickness of the inlet sealing ring and the maximum wear thickness of the outlet sealing ring (ensuring that the elastic force of the disc spring can provide the actual required sealing force).

[0007] In this invention, the nut is embedded in the mounting groove on the outer surface of the outlet plate; the sliding plate sealing force adjusting bolt passes through the disc spring, the inlet plate, and the outlet plate in sequence and is threaded into the nut; the sliding plate sealing force adjusting bolt and the matching disc spring and nut are the same in number, eight in total, with the eight nuts arranged in pairs and completely blocked and limited by four strip-shaped integral nut check keys (on the one hand, the nut check keys can prevent the nuts from loosening and ensure the durability of the sealing force; on the other hand, the integral nut check keys can completely block the nuts, preventing corrosive materials from spraying onto the nuts and extending the service life of the nuts).

[0008] The present invention uses four slide width adjusting bolts; each pair of slide width adjusting bolts are symmetrically distributed on the left and right, and the net spacing matches the width of the slide plate (the end faces of the four adjusting bolts form an accurate slide, ensuring that the slide plate can smoothly move back and forth along a straight line); each slide width adjusting bolt is arranged between two slide plate sealing force adjusting bolts in the length direction of the slide base and will not cause positional interference.

[0009] In this invention, the thickness of the outlet sealing ring is greater than that of the inlet sealing ring (because the outlet sealing ring has to withstand a greater pressure difference than the inlet sealing ring, and the outlet sealing ring will wear out faster than the inlet sealing ring, so the thickness of the outlet sealing ring needs to be designed to be greater than that of the inlet sealing ring).

[0010] In this invention, the filter screen is embedded in the groove of the feed end cavity of the perforated plate, and the perforated plate is installed in the stepped cavity of the slide plate and fastened by the perforated plate fixing screws installed in the width direction. (In this invention, the perforated plate with the largest contact area with the material is designed as a detachable structure and connected to the slide plate by the perforated plate fixing screws. In this way, the perforated plate can be replaced or cleaned in time, just like the inlet sealing ring and the outlet sealing ring, so as to meet the filtration needs of this invention for special materials with poor flowability or corrosiveness.)

[0011] The U-shaped frame described in this invention is a U-shaped support frame formed by two double-headed positioning rods vertically fixed to the same side of the support base plate (providing an installation base for the slide base and the hydraulic cylinder); the slide base is fixed to the other end of the two double-headed positioning rods; the hydraulic cylinder is fixed to the rear end face of the support base plate, and the front end of the hydraulic cylinder rod is connected to the rear end of the slide plate by a hinge (when the screen needs to be replaced, the hydraulic cylinder drives the slide plate to move backward or forward).

[0012] When the cylinder rod of the hydraulic cylinder in this invention retracts to perform online screen replacement, the filter unit located at the rear end of the slide plate is in the screen replacement position, and the filter unit located at the front end of the slide plate is in the filtration position (the usage state of Embodiment 1).

[0013] When the cylinder rod of the hydraulic cylinder in this invention pushes forward to perform online screen replacement, the filter unit located at the front end of the slide plate is in the screen replacement position, and the filter unit located at the rear end of the slide plate is in the filtration position (the usage state of Embodiment 2).

[0014] The design principle of this invention is as follows: This invention retains the main structure of the slide plate filter screen changing device, including the slide plate, filter unit, cylinder, and U-shaped frame. The main improvement is to the sealing structure – specifically, a new external flexible sealing structure is designed to replace the traditional rigid seal with gaps or the internal flexible seal structure. The sealing principle of the external flexible sealing structure is as follows: the elastic force generated by the compression of the disc spring by the slide plate sealing force adjusting bolt serves as the sealing force between the slide plate and the inlet sealing ring, and between the slide plate and the outlet sealing ring. The sealing force is automatically adjusted, achieving a gapless, natural fit between the sealing ring and the slide plate, ensuring a good sealing effect with zero material leakage and smooth, unobstructed movement of the slide plate during screen changing. The sealing force can be adjusted as needed to meet the filtration sealing requirements of various materials. Automatic sealing compensation is achieved after the sealing ring wears, greatly improving sealing durability and extending sealing time, maintaining a good sealing effect for a long time without leakage. The flow channel and sealing surface are always dynamically fitted without dead angles, preventing material melt from stagnating at the sealing interface and effectively avoiding contamination caused by long-term material retention in the stagnant area.

[0015] A more detailed analysis of the design of the external flexible sealing structure is as follows: First, because different materials have different flow resistances, the resulting back pressures are also different, leading to different sealing forces required for leakage. However, since the compression amplitude of the disc spring can be adjusted, and it is equipped with preset adjustment gaps for the thickness of the inlet sealing ring, the thickness of the outlet sealing ring, and the sealing force adjustment bolts of the slide plate, the corresponding elastic force and sealing force are adjustable. Thus, this invention can achieve automatic and on-demand adjustment of the sealing force, which can meet the filtration and sealing needs of various materials. It can achieve a gapless and natural fit between the sealing ring and the slide plate, ensuring a good sealing effect with zero material leakage, and ensuring smooth sliding of the slide plate without jamming during screen changing. It has the advantages of automatic sealing, adjustable sealing force, zero leakage, anti-jamming, and strong versatility. More specifically, traditional rigid seals are gap-fit ​​seals, which either leak if the gap is too large or get stuck if the gap is too small. In contrast, the external flexible seal of this invention is a gapless, naturally fitting seal. That is, although the slide plate in this invention is fitted without gap by the front and rear sealing rings, it is not squeezed shut. When the sliding plate's movement resistance is too high, the front and rear sealing rings, together with the corresponding inlet and outlet plates, have a slight outward displacement in the axial direction. This is because the disc spring will produce stepless elastic deformation, providing a slight micron-level clearance for the movement of the slide plate. In addition, the processing precision of the slide plate itself also requires a slight elastic self-adjusting displacement in the axial direction, consistent with the compensatory adjustment after the sealing rings wear.

[0016] Secondly, although the present invention may cause slight wear on the sealing surface during screen replacement, the inlet plate carrying the inlet sealing ring or the outlet plate carrying the outlet sealing ring will automatically adhere to the slide plate under the elastic force of the disc spring. This means the external flexible sealing structure has an automatic sealing compensation function, which can greatly improve sealing durability and extend sealing effectiveness, maintaining a good sealing effect for a long time without leakage. It has the advantages of automatic sealing compensation, good sealing durability, long sealing effectiveness, zero leakage, and long service life. Even if the inlet or outlet sealing ring is severely worn, and the sealing force generated by the disc spring decreases, the elastic force of the disc spring can be changed by readjusting the torque of the slide plate sealing force adjusting bolt using a torque wrench.

[0017] Third, the flow path of the filtered material melt in this invention—the material melt enters the slide base from the inlet plate, then enters the filter unit embedded in the slide plate and located at the filtration station through the inlet sealing ring for filtration, and flows out through the outlet sealing ring and outlet plate after filtration. Compared with the traditional built-in mechanical flexible sealing structure, since the built-in mechanical flexible sealing structure relies on the back pressure of the material melt, the mating area between the inlet sealing ring and the inlet plate is specially designed with a material melt receiving cavity to form the sealing force of the sealing ring. Therefore, a portion of the material melt will be displaced in the receiving cavity, but a large amount will remain, forming a dead zone. This is fatal for materials or catalysts that are susceptible to retention and corrosion, such as PSU, PVC, PVDF, and some catalysts. In addition, compared with traditional rigid seals with natural gaps, rigid seals with natural gaps are not absolutely sealed and have gaps. More or less, there will be material melt overflow. The surface of the rigid seal's slide plate or cylinder always has a layer of melt that acts as a lubricant. Otherwise, the slide plate or cylinder will easily get stuck during movement. Over time, the surface melt will age and degrade until it carbonizes. These degraded or carbonized materials cannot be completely removed. The residue will be carried back to the main channel when the screen is changed, thus contaminating the brand-new virgin material melt. Because this invention uses an external flexible sealing structure, the inlet or outlet sealing ring automatically adheres to the slide plate under the elastic force of the disc spring, preventing material leakage. All molten material flows and is filtered along the aforementioned flow path. In other words, there are no dead zones between the flow channel in contact with the molten material and the sealing structure in this invention. Unlike traditional built-in sealing structures, there is no stagnation at the sealing interface, and unlike traditional rigid seals with natural gaps, there is no layer of stagnant molten material remaining on the slide plate surface. Therefore, this invention can effectively avoid adverse effects such as contamination caused by long-term stagnation of material in the stagnation area, and has the advantages of no material stagnation and no contamination.

[0018] Fourth, this invention has the advantages of strong versatility, wide applicability, convenient online screen replacement, and ease of use. More specifically, this invention features a single-slide, dual-station structure, with two filter units embedded in the slide. One filter unit is in the filtration station, while the other is in the screen replacement station. When the filter needs to be replaced, the slide is quickly pulled backward (Example 1) or pushed forward (Example 2) by the hydraulic cylinder to move it horizontally, exchanging the positions of the two filter units. The dirty filter is removed, and a clean filter is installed for later use. The other filter unit remains in its filtration station, maintaining normal filtration operation. This process is repeated for each screen replacement, making online screen replacement very convenient. Furthermore, this invention is a slide-type filter screen replacement device with an external flexible sealing structure. Besides being suitable for filtering conventional materials, it is also suitable for materials with poor flowability or corrosiveness, offering advantages of strong versatility and wide applicability. More specifically, when this invention is used for materials with poor flowability or corrosiveness, it not only requires the ability to quickly switch workstations, but also requires that the materials of the slide base, inlet sealing ring, outlet sealing ring, perforated plate, and slide plate be wear-resistant and corrosion-resistant. In addition, this invention also designs the perforated plate, which has the largest contact area with the material, as a detachable structure—that is, it is connected to the slide plate by the perforated plate fixing screws. In this way, the perforated plate can also be replaced or cleaned in a timely manner, just like the inlet sealing ring and outlet sealing ring, to meet the filtration needs of this invention for special materials with poor flowability or corrosiveness. In addition, a nut check key is designed to seal and protect the nut to reduce corrosion and extend the service life of components such as the slide plate sealing force adjustment bolt.

[0019] The beneficial technical effects of the present invention are as follows: This invention enables automatic and on-demand adjustment of the sealing force, meeting the filtration sealing requirements of various materials. It achieves a seamless, natural fit between the sealing ring and the slide plate, ensuring both zero leakage and smooth, unobstructed sliding plate movement during screen replacement. Furthermore, it provides automatic seal compensation, significantly improving seal durability and extending sealing lifespan, maintaining a good seal for extended periods without leakage. This invention also prevents molten material from accumulating at the sealing interface, effectively avoiding contamination caused by prolonged material retention. Therefore, this invention offers advantages such as automatic sealing, adjustable sealing force, zero leakage, anti-jamming, automatic seal compensation, excellent seal durability, long sealing lifespan, no material retention, no contamination, strong versatility, wide applicability, long service life, easy online screen replacement, and convenient use. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the usage state of Embodiment 1 of the present invention (i.e., the network switching station is at the back end).

[0021] Figure 2 yes Figure 1A-A cross-section.

[0022] Figure 3 yes Figure 2 The C-direction view.

[0023] Figure 4 yes Figure 1 B-B cross-section view.

[0024] Figure 5 This is a schematic diagram of the usage state of Embodiment 2 of the present invention (i.e., the screen changing station is at the front end).

[0025] Part numbering in the diagram: 1. Inlet plate; 2. Inlet sealing ring thickness adjustment gap; 3. Inlet sealing ring; 4. Filter screen; 5. Three-step cavity; 6. Disc spring; 7. Slide width adjustment bolt; 8. Outlet plate; 9. Outlet sealing ring thickness adjustment gap; 10. Slide plate; 11. Outlet sealing ring; 12. Perforated plate; 13. Perforated plate fixing screw; 14. Nut check key; 15. Nut; 16. Slide plate sealing force adjustment bolt; 17. Hinge; 18. Hydraulic cylinder; 18-1. Hydraulic cylinder rod; 19. U-shaped frame; 19-1. Double-headed positioning support rod; 19-2. Support base plate; 20. Slide base; 21. Filter unit; 22. Thickness adjustment guarantee gap. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings: like Figures 1-5As shown, the present invention discloses a slide plate type filter replacement device with an external flexible sealing structure, comprising a slide base 20 and a hydraulic cylinder 18 respectively fixed at the front and rear ends of a U-shaped frame 19 (the U-shaped frame 19 provides an installation and support base for the slide base 20 and the hydraulic cylinder 18; the hydraulic cylinder 18 provides driving power for the slide plate 10; the slide base 20 provides a guiding and supporting base for the slide plate 10, and also provides installation space for sealing components such as the inlet sealing ring 3, the outlet sealing ring 11, and the slide plate sealing force adjusting bolt 16), and a slide plate 10 that extends through the slide base 20 along its length and can slide back and forth under the drive of the hydraulic cylinder 18 (when the filter needs to be replaced, it can be quickly pulled backward (Embodiment 1) or pushed forward (Embodiment 2) by the drive of the hydraulic cylinder 18). Example 2) The slide plate 10 is moved horizontally, causing the positions of the two filter units 21 to be interchanged. The dirty filter screen 4 is removed and a clean filter screen 4 is installed for later use, while the other filter unit 21 is located in the filter position for normal filtration. Two sets of filter units 21, composed of filter screens 4 and perforated plates 12, are embedded at intervals along the longitudinal center line of the slide plate 10 (one filter unit 21 is in the filter position, while the other filter unit 21 is in the screen replacement position). The slide base 20 is a combined base formed by the inlet plate 1 and the outlet plate 8 being interlocked in the thickness direction and fastened together by the slide plate sealing force adjusting bolt 16 penetrating the thickness direction and the matching nut 15, nut check key 14, and disc spring 6 (the sealing of the present invention). The principle is as follows: the elastic force generated by the compression of the disc spring 6 by the sliding plate sealing force adjusting bolt 16 serves as the sealing force between the sliding plate 10 and the inlet sealing ring 3, and between the sliding plate 10 and the outlet sealing ring 11. The sealing force can be automatically adjusted to achieve a gapless and natural fit between the sealing ring and the sliding plate, ensuring a good sealing effect with zero material leakage, and ensuring smooth sliding plate movement without jamming during screen changing. The sealing force can be adjusted as needed to meet the filtration sealing requirements of various materials. Automatic sealing compensation can be achieved after the sealing ring wears, greatly improving sealing durability and extending sealing time, maintaining a good sealing effect for a long time without leakage. The mating surface of the inlet plate 1 is symmetrical, with convex ends and a stepped groove with continuous stepped depressions in the middle section. The upper cavity surface of the outlet plate 8 has a symmetrical interlocking surface with concave ends and a stepped groove lower cavity surface with two convex and one concave sections in the middle. The upper cavity surface and the lower cavity surface of the stepped groove interlock to form a three-step cavity 5 (providing installation space for the inlet sealing ring 3, the sliding plate 10, and the outlet sealing ring 11). The middle cavity section of the three-step cavity 5 is fitted with the inlet sealing ring 3, the sliding plate 10, and the outlet sealing ring 11 in sequence from top to bottom. The upper cavity of the two end cavities in the three-step cavity 5 is the inlet sealing ring thickness adjustment gap 2 (providing a reserved gap for automatic sealing compensation after the inlet sealing ring 3 wears). The lower cavity of the two end cavities in the three-step cavity 5 is the outlet sealing ring thickness adjustment gap 9 (providing a reserved gap for automatic sealing compensation after the outlet sealing ring 11 wears).A thickness adjustment gap 22 is reserved between the protruding interlocking section at the end of the inlet plate 1 and the recessed interlocking section at the end of the outlet plate 8 (to provide a reserved gap for automatic sealing compensation after wear of the inlet sealing ring 3 and the outlet sealing ring 11); the left and right end faces of the slide plate 10 are respectively in contact with the slide width adjustment bolts 7 that penetrate the protrusion at the end of the inlet plate along the width direction (the slide width adjustment bolts 7 are used to adjust the position of the slide plate 10 in the width direction and serve as a sliding guide).

[0027] In this invention, the narrowest point of the inlet sealing ring thickness adjustment gap 2 is greater than the maximum wear thickness of the inlet sealing ring 3 (ensuring that no motion interference occurs during automatic sealing compensation after the inlet sealing ring 3 wears); the narrowest point of the outlet sealing ring thickness adjustment gap 9 is greater than the maximum wear thickness of the outlet sealing ring 11 (ensuring that no motion interference occurs during automatic sealing compensation after the outlet sealing ring 11 wears); the thickness adjustment ensures that the gap 22 is not less than the sum of the maximum wear thickness of the inlet sealing ring 3 and the maximum wear thickness of the outlet sealing ring 11 (ensuring that no motion interference occurs during automatic sealing compensation after the inlet sealing ring 3 and the outlet sealing ring 11 wear).

[0028] In this invention, the disc spring 6 is embedded in the mounting groove opened on the outer surface of the inlet plate 1, and the elastic extension of the disc spring 6 is greater than the sum of the maximum wear thickness of the inlet sealing ring 3 and the maximum wear thickness of the outlet sealing ring 11 (ensuring that the elastic force of the disc spring 6 can provide the actual required sealing force).

[0029] In this invention, the nut 15 is fitted into the mounting groove on the outer surface of the outlet plate 8; the sliding plate sealing force adjusting bolt 16 passes through the disc spring 6, the inlet plate 1, and the outlet plate 8 in sequence and is threaded into the nut 15; the sliding plate sealing force adjusting bolt 16 and the matching disc spring 6 and nut 15 are the same in number, eight in total, of which the eight nuts 15 are paired up and completely blocked and limited by four strip-shaped integral nut check keys 14 (on the one hand, the nut check keys 14 can prevent the nuts (15) from loosening and ensure the durability of the sealing force; on the other hand, the integral nut check keys 14 can completely block the nuts 15, which can prevent corrosive materials from spraying onto the nuts 15 and extend the service life of the nuts 15).

[0030] The present invention uses four slide width adjusting bolts 7; each pair of slide width adjusting bolts 7 are symmetrically distributed on the left and right, and the net spacing matches the width of the slide plate 10 (the end faces of the four adjusting bolts 7 form an accurate slide, ensuring that the slide plate 10 can smoothly move back and forth along a straight line); each slide width adjusting bolt 7 is arranged between two slide plate sealing force adjusting bolts 16 in the length direction of the slide base 20 and will not cause positional interference.

[0031] In this invention, the thickness of the outlet sealing ring 11 is greater than the thickness of the inlet sealing ring 3 (because the outlet sealing ring 11 has to withstand a greater pressure difference than the inlet sealing ring 3, and the outlet sealing ring 11 will wear out faster than the inlet sealing ring 3, so the thickness of the outlet sealing ring 11 needs to be designed to be greater than the thickness of the inlet sealing ring 3).

[0032] In this invention, the filter screen 4 is embedded in the groove of the feed end cavity of the perforated plate 12. The perforated plate 12 is embedded in the stepped cavity of the slide plate 10 and fastened by the perforated plate fixing screws 13 embedded in the width direction. (In this invention, the perforated plate 12 with the largest contact area with the material is designed as a detachable structure and connected to the slide plate 10 by the perforated plate fixing screws 13. In this way, the perforated plate can be replaced or cleaned in time, just like the inlet sealing ring 3 and the outlet sealing ring 11, so as to meet the filtration needs of this invention for special materials with poor flowability or corrosiveness.)

[0033] The U-shaped frame 19 described in this invention is a U-shaped support frame formed by two double-headed positioning rods 19-1 vertically fixed on the same side of the support base plate 19-2 (providing an installation base for the slide base 20 and the hydraulic cylinder 18); the slide base 20 is fixed to the other end of the two double-headed positioning rods 19-1; the hydraulic cylinder 18 is fixed to the rear end face of the support base plate 19-2, and the front end of the hydraulic cylinder rod 18-1 is connected to the rear end of the slide plate 10 through a hinge 17 (when the screen needs to be replaced, the hydraulic cylinder 18 drives the slide plate 10 to move backward or forward).

[0034] When the cylinder rod 18-1 of the hydraulic cylinder 18 in this invention retracts backward to perform online screen replacement, the filter unit 21 located at the rear end of the slide plate 10 is in the screen replacement position, and the filter unit 21 located at the front end of the slide plate 10 is in the filtration position (the usage state of Embodiment 1).

[0035] When the cylinder rod 18-1 of the cylinder 18 described in this invention is pushed forward to perform online screen replacement, the filter unit 21 located at the front end of the slide plate 10 is in the screen replacement position, and the filter unit 21 located at the rear end of the slide plate 10 is in the filtration position (the usage state of Embodiment 2).

[0036] The specific uses of this invention are as follows: Filtration Process: The molten material to be filtered enters the slide base 20 from the inlet plate 1 in this invention, and then enters the filter unit 21 embedded in the slide plate 10 and located at the filtration station for filtration—that is, it passes through the filter screen 4 and the porous plate 12 in sequence to remove impurities. The clean molten material after filtration flows out through the outlet sealing ring 11 and the outlet plate 8. In this process, the sealing force between the slide plate 10 and the inlet sealing ring 3, and between the slide plate 10 and the outlet sealing ring 11, is provided by the elastic force generated by the compression of the disc spring 6 by the slide plate sealing force adjusting bolt 16. Since the elastic force can be automatically adjusted, the sealing force can also be automatically adjusted, which can achieve a gapless natural fit and seal between the slide plate 10 and the inlet sealing ring 3, and between the slide plate 10 and the outlet sealing ring 11. This ensures a good sealing effect with zero material leakage and ensures smooth sliding of the slide plate without jamming during screen changing. At the same time, the sealing force can be adjusted as needed to meet the requirements of various materials. Filter sealing; when the inlet sealing ring 3 or the outlet sealing ring 11 wears, the inlet plate 1 will carry the inlet sealing ring 3 or the outlet plate 8 will carry the outlet sealing ring 11 and automatically stick to the slide plate 10 under the elastic force of the disc spring 6, which can realize automatic sealing compensation, greatly improve the sealing durability, extend the sealing time, and maintain a good sealing effect for a long time without leakage; in addition, since the flow channel and the sealing surface are always dynamically fitted without dead corners, the material melt will not be retained at the sealing joint surface, effectively avoiding the contamination caused by the material being retained in the retention area for a long time.

[0037] Screen changing process: Two filter units 21 are embedded in the slide plate 10 of this invention – one filter unit 21 is in the filtration position, and the other filter unit 21 is in the screen changing position. When the filter needs to be replaced, the slide plate 10 is quickly pulled backward (Embodiment 1) or pushed forward (Embodiment 2) by the drive of the hydraulic cylinder 18, so that the positions of the two filter units 21 are interchanged. The dirty filter 4 is removed and a clean filter 4 is installed for later use, while the other filter unit 21 is in the filtration position for normal filtration. The above operation is repeated each time the filter needs to be changed.

Claims

1. A slide-type filter screen changing device with an external flexible sealing structure, comprising a slide base (20) and a hydraulic cylinder (18) respectively fixed at the front and rear ends of a U-shaped frame (19), a slide plate (10) that runs through the slide base (20) along its length and can slide back and forth under the drive of the hydraulic cylinder (18), and two sets of filter units (21) composed of filter screens (4) and perforated plates (12) that are embedded at intervals along the longitudinal center line of the slide plate (10); characterized in that: The slide base (20) is a combined base formed by interlocking the inlet plate (1) and the outlet plate (8) in the thickness direction and fastening them together with the sliding plate sealing force adjusting bolt (16) that runs through the thickness direction and the matching nut (15), nut check key (14), and disc spring (6); the interlocking surface of the inlet plate (1) is symmetrical from left to right, with the end protruding and the middle section being a stepped groove upper cavity surface with continuous stepped depression; the interlocking surface of the outlet plate (8) is symmetrical from left to right, with the end concave and the middle section being a stepped groove lower cavity surface with two protrusions and one concavity; the stepped groove upper cavity surface and the stepped groove lower cavity surface interlock to form a three-step cavity (5); the three-step The middle section of the stepped cavity (5) is fitted with an inlet sealing ring (3), a sliding plate (10), and an outlet sealing ring (11) from top to bottom. The upper part of the two end sections of the three-step stepped cavity (5) is the thickness adjustment gap (2) of the inlet sealing ring, and the lower part of the two end sections of the three-step stepped cavity (5) is the thickness adjustment gap (9) of the outlet sealing ring. A thickness adjustment guarantee gap (22) is reserved between the protruding interlocking surface section at the end of the inlet plate (1) and the recessed interlocking surface section at the end of the outlet plate (8). The left and right end faces of the sliding plate (10) are respectively in contact with the slide width adjustment bolt (7) that runs through the protruding end of the inlet plate along the width direction.

2. The slide-type filter screen changing device with an external flexible sealing structure according to claim 1, characterized in that: The narrowest gap of the inlet sealing ring thickness adjustment gap (2) is greater than the maximum wear thickness of the inlet sealing ring (3); the narrowest gap of the outlet sealing ring thickness adjustment gap (9) is greater than the maximum wear thickness of the outlet sealing ring (11); the gap of the thickness adjustment guarantee gap (22) is not less than the sum of the maximum wear thickness of the inlet sealing ring (3) and the maximum wear thickness of the outlet sealing ring (11).

3. A slide-type filter screen changing device with an external flexible sealing structure according to claim 1, characterized in that: The disc spring (6) is embedded in the mounting groove opened on the outer surface of the inlet plate (1), and the elastic extension of the disc spring (6) is greater than the sum of the maximum wear thickness of the inlet sealing ring (3) and the maximum wear thickness of the outlet sealing ring (11).

4. A slide-type filter screen changing device with an external flexible sealing structure according to claim 1, characterized in that: The nut (15) is fitted into the mounting groove on the outer surface of the outlet plate (8); the sliding plate sealing force adjusting bolt (16) passes through the disc spring (6), the inlet plate (1), and the outlet plate (8) in sequence and is threaded into the nut (15); the sliding plate sealing force adjusting bolt (16) and the matching disc spring (6) and nut (15) are the same, all eight, of which the eight nuts (15) are paired up and completely blocked and limited by four strip-shaped nut check keys (14).

5. A slide-type filter screen changing device with an external flexible sealing structure according to claim 1, characterized in that: The number of the slide width adjusting bolts (7) is four; each pair of slide width adjusting bolts (7) are symmetrically distributed on the left and right, and the net spacing matches the width of the slide plate (10); each slide width adjusting bolt (7) is arranged between the two slide plate sealing force adjusting bolts (16) in the length direction of the slide base (20) and will not cause positional interference.

6. A slide-type filter screen changing device with an external flexible sealing structure according to claim 1, characterized in that: The thickness of the outlet sealing ring (11) is greater than the thickness of the inlet sealing ring (3).

7. A slide-type filter screen changing device with an external flexible sealing structure according to claim 1, characterized in that: The filter screen (4) is embedded in the groove of the feed end cavity of the perforated plate (12), and the perforated plate (12) is embedded in the stepped cavity of the slide plate (10) and fastened by the perforated plate fixing screw (13) embedded in the width direction.

8. A slide-type filter screen changing device with an external flexible sealing structure according to claim 1, characterized in that: The U-shaped frame (19) is a U-shaped support frame formed by two double-headed positioning rods (19-1) vertically fixed on the same side of the support base plate (19-2); the slide base (20) is fixed at the other end of the two double-headed positioning rods (19-1); the oil cylinder (18) is fixed on the rear end face of the support base plate (19-2), and the front end of the oil cylinder rod (18-1) is connected to the rear end of the slide plate (10) by a hinge (17).

9. A slide-type filter screen changing device with an external flexible sealing structure according to claim 7, characterized in that: When the cylinder rod (18-1) of the cylinder (18) retracts backward to perform online screen replacement, the filter unit (21) located at the rear end of the slide plate (10) is in the screen replacement position, and the filter unit (21) located at the front end of the slide plate (10) is in the filter position.

10. A slide-type filter screen changing device with an external flexible sealing structure according to claim 7, characterized in that: When the cylinder rod (18-1) of the cylinder (18) is pushed forward to perform online screen replacement, the filter unit (21) located at the front end of the slide plate (10) is in the screen replacement position, and the filter unit (21) located at the rear end of the slide plate (10) is in the filter position.

Images