Production device and process of micro-filtration PE sintered pipe with asymmetric structure

Abstract

The invention relates to the technical field of sintered pipe production, in particular to a production device and process for a microfiltration PE sintered pipe of an asymmetric structure, and the production device comprises a mold which is used for filling ultra-high molecular weight polyethylene powder with different particle sizes and putting the ultra-high molecular weight polyethylene powder into a sintering furnace for sintering molding to obtain the PE sintered pipe; the vibration assembly is connected with one end or two ends of the axis of the mold, and the vibration assembly is used for layering the ultra-high molecular weight polyethylene powder in the mold according to the particle size through high-frequency vibration; wherein the large-particle ultra-high molecular weight polyethylene powder moves in the axis direction to form an inner layer, the small-particle ultra-high molecular weight polyethylene powder moves away from the axis to form an outer layer, and after vibration is completed, the PE sintered pipe is obtained through sintering forming in a sintering furnace. According to the invention, the design limitation of uniform pore diameter of a traditional sintering tube is broken through, continuous distribution of gradient pore diameter is realized through vibration layering and precise sintering control, and the contradiction that a traditional product is low in flux if being high in filtering precision and insufficient in precision if being high in flux is structurally solved; an additional binder is not needed, only the PE particles are melted and bonded, the situation that the filter effect is affected by binder residues is avoided, and meanwhile the material compatibility and the structural stability are improved.

Description

Technical Field

[0001] This invention relates to the field of sintered tube production technology, and in particular to a production apparatus and process for an asymmetric structure microfiltration PE sintered tube. Background Technology

[0002] Ultra-high molecular weight polyethylene (UHMW-PE) sintered tubes are widely used in fluid filtration due to their strong chemical stability and resistance to contamination. However, most existing PE sintered tubes have symmetrical pore structures, making it difficult to balance filtration precision and throughput, resulting in an inherent contradiction: "high precision means low throughput, and high throughput means insufficient precision." A few attempts to prepare asymmetric structures either involve molding multiple layers of powder separately and then bonding and sintering them, which easily leads to weak interlayer adhesion, risk of detachment, and discontinuous pore size gradients; or using complex molds for partitioned feeding, which is cumbersome, costly, and difficult to achieve industrial mass production. Furthermore, existing technologies lack precise layering and sintering control, easily leading to uneven pore size distribution and unstable filtration performance, making it impossible to efficiently prepare an integrated asymmetric filtration structure with coarse inner pores and fine outer pores, thus limiting the application of PE sintered tubes in high-precision filtration scenarios. Therefore, we propose a production device and process for asymmetric structure microfiltration PE sintered tubes. Summary of the Invention

[0003] Based on the technical problems existing in the background technology, this invention proposes a production device and process for asymmetric structure microfiltration PE sintered tubes. Through vibration layering and precise sintering control, a continuous distribution of gradient pore size is achieved, which structurally solves the contradiction that traditional products have high filtration accuracy but low flux and high flux but insufficient accuracy. No additional binder is required, and the PE particles themselves melt and bond, avoiding the influence of binder residue on the filtration effect, while improving material compatibility and structural stability.

[0004] This invention provides the following technical solution: a production apparatus for asymmetric structure microfiltration PE sintered tubes, comprising:

[0005] A mold is used to fill ultra-high molecular weight polyethylene powder with different particle sizes and sinter it in a sintering furnace to obtain a PE sintered pipe.

[0006] A vibration assembly is connected to one or both ends of the mold axis. The vibration assembly is used to cause ultra-high molecular weight polyethylene powder in the mold to be layered according to particle size through high-frequency vibration.

[0007] In this process, large-particle ultra-high molecular weight polyethylene powder moves towards the axis to form the inner layer, while small-particle ultra-high molecular weight polyethylene powder moves away from the axis to form the outer layer. After vibration, the material is placed in a sintering furnace for sintering to obtain a PE sintered pipe.

[0008] Preferably, the mold includes:

[0009] The first mold, located away from the axis of the PE sintered tube, is used to support the outer wall of the PE sintered tube.

[0010] The second mold is located on the axis of the PE sintered tube and is used to support the inner wall of the PE sintered tube.

[0011] The axes of the first mold and the second mold coincide, and the first mold and the second mold cooperate to form a closed space, or a closed space is formed by combining sealing elements.

[0012] Preferably, the seal includes:

[0013] The first sealing element is used to seal one end of the first mold and the second mold.

[0014] Preferably, the seal further includes:

[0015] The second seal is used to seal the other end of the first mold and the second mold.

[0016] Preferred options also include:

[0017] A first fastener, which is formed in a first mold, a second mold, or a first seal, or is connected to a first mold, a second mold, or a first seal;

[0018] The first fastener is used to fix the first seal to the first mold and the second mold and form a sealed space.

[0019] Preferred options also include:

[0020] The second fastener is formed in the first mold, the second mold, or the second seal, or is connected to the first mold, the second mold, or the second seal;

[0021] The second fastener is located on the opposite side of the first fastener, and works with the first fastener to fix the second seal to the first mold and the second mold, and together with the first seal to form a sealed space.

[0022] Preferably, the vibration assembly includes:

[0023] A first vibration motor is connected to the axial end of the second mold.

[0024] The first vibration motor is used to drive the second mold to vibrate at high frequency, so that the ultra-high molecular weight polyethylene powder in the mold is layered according to the particle size.

[0025] Preferably, the vibration assembly further includes:

[0026] The second vibration motor is connected to the other end of the second mold in the axial direction;

[0027] The second vibration motor and the first vibration motor move at the same frequency through a control module, which drives the second mold to vibrate at high frequency, causing the ultra-high molecular weight polyethylene powder in the mold to be layered according to particle size.

[0028] Preferred options also include:

[0029] A coupling for connecting the mold and the vibration assembly, and for transmitting the high-frequency vibration of the vibration assembly to the mold;

[0030] A feed inlet, which is formed in or connected to the first mold;

[0031] The feed inlet is equipped with a matching sealing cap. The feed inlet is used to add ultra-high molecular weight polyethylene powder of different particle sizes into the mold, and the sealing cap is used to seal the feed inlet.

[0032] The sealing cap can be combined with either the first sealing element or the second sealing element;

[0033] A filler, the filler being used to level the ultra-high molecular weight polyethylene powder in the mold;

[0034] The filler is formed on the sealing cap, connected to the sealing cap, or coupled to the feed inlet.

[0035] A manufacturing process for an asymmetric structure microfiltration PE sintered tube includes the following steps:

[0036] S1. Material preparation: Fill the mold with ultra-high molecular weight polyethylene powder of different particle sizes;

[0037] S2. Vibration stratification: The mold includes an outer cylinder and a central core rod. The two ends of the core rod are connected to a high-frequency vibration motor. Through high-frequency vibration, the ultra-high molecular weight polyethylene powder in the mold is stratified according to the particle size. Large PE particles form the inner layer, and small PE particles form the outer layer.

[0038] S3. Sintering: The mold filled with PE powder is placed in a sintering furnace. At the set temperature, the surface of the PE particles begins to melt, and the melted parts between the PE particles form a connection. After cooling, the mold is demolded to form a sintered tube with a large inner channel and a dense small pore layer on the outside.

[0039] This invention provides a production device and process for asymmetric structure microfiltration PE sintered tubes. Dual vibration motors are driven in the same frequency and direction through a control module, which drives the second mold in the center to generate stable high-frequency vibration. With the help of the vibration sieving effect, the powder is naturally layered according to the particle size. Large particles gather towards the axis to form a coarse inner layer, while small particles diffuse outward to form a fine outer layer. Through the melting and bonding of the raw materials during the sintering process, a seamless combination of the inner and outer layers is achieved, which ensures both filtration accuracy (small pores on the surface) and throughput and dirt holding capacity (large pores in the inner layer). Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 ;

[0041] Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 ;

[0042] Figure 3 This is a schematic diagram of the structure of the present invention. Figure 3 ;

[0043] Figure 4 This is a process flow diagram of the present invention.

[0044] In the figure: 1. First mold; 2. Second mold; 3. First seal; 4. Second seal; 5. First fastener; 6. Second fastener; 7. First vibration motor; 8. Second vibration motor; 9. First coupling; 10. Second coupling; 11. Feed port; 12. Filler; 13. Sealing cover. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] like Figure 1 As shown, the present invention provides a technical solution: a production apparatus for an asymmetric structure microfiltration PE sintered tube, comprising:

[0047] A mold is used to fill ultra-high molecular weight polyethylene powder with different particle sizes and sinter it in a sintering furnace to obtain a PE sintered pipe.

[0048] The mold has a modular structure, with the core consisting of a first mold 1 and a second mold 2 arranged coaxially. Both are made of 304 / 316L stainless steel (corrosion-resistant, high-temperature resistant, and suitable for sintering conditions). The connection method is that the first mold 1 (round tube shape) is sleeved on the outside of the second mold 2 (solid rod shape or hollow shape), and the gap between the two forms a powder filling cavity. Optional options include forming a sealed space by the mold itself (high-precision fit), or by using a sealing element to assist in sealing. The advantage is that the structure is modular, and the mold specifications can be flexibly changed according to the size of the sintering tube. At the same time, it provides a stable forming carrier for vibration stratification and subsequent sintering, ensuring the consistency of product wall thickness and outer diameter.

[0049] Vibration assembly, which is connected to one or both ends of the mold axis, is used to cause ultra-high molecular weight polyethylene powder in the mold to be layered according to particle size through high-frequency vibration.

[0050] The vibration assembly is specifically a combination of high-frequency electromagnetic vibration motors, with the core consisting of 1-2 vibration motors (power 1.5-5.5kW, frequency adjustable from 200-500Hz). The connection method is to connect to the connecting shaft section at the axial end of the second mold 2 via a coupling. Options include connecting a single motor at one end (for small short molds) or connecting one motor at each end (for long molds). The advantage is that the connection method can be selected as needed. When two motors work together, they can achieve synchronous and unidirectional vibration through the control module, and the vibration energy is evenly transferred to the powder to ensure the stratification effect. A single motor simplifies the structure, reduces costs, and adapts to different mass production needs.

[0051] In this process, large-particle ultra-high molecular weight polyethylene powder moves towards the axis to form the inner layer, while small-particle ultra-high molecular weight polyethylene powder moves away from the axis to form the outer layer. After vibration, the material is placed in a sintering furnace for sintering to obtain a PE sintered pipe.

[0052] This process relies on the vibration sieving effect. Large particles (80-120 mesh) gather towards the second mold 2 (axis) due to strong inertial force, forming a coarse inner layer with a pore size of 50-100μm. Small particles (200-300 mesh) have weak inertial force and are constrained by the inner wall of the first mold 1, forming a fine outer layer with a pore size of 5-20μm. Optionally, the particle size ratio can be adjusted according to filtration requirements to change the pore size gradient between the inner and outer layers. The advantage is that it does not require multi-layer step-by-step molding. A continuous gradient structure can be formed with one vibration. There are no obvious boundaries between the layers. After subsequent sintering, they are seamlessly fused, avoiding layer detachment and balancing filtration accuracy (outer layer) and throughput (inner layer).

[0053] In some embodiments, the mold includes: a first mold 1.

[0054] The first mold 1 is located away from the axis of the PE sintering tube and is used to support the outer wall of the PE sintering tube. The first mold 1 is a cylindrical structure, and the material can be selected from 304 stainless steel (general working condition) or 316L stainless steel (corrosion resistant working condition). The length is adjustable from 1 to 3 meters, the inner diameter is 50-200 mm, and the inner wall is finely ground (roughness Ra≤0.8μm). The connection method is to fix it to the integrated vibration bracket by arc-shaped clamps, and the two ends are in contact with the sealing parts. Optionally, a wear-resistant coating (such as a ceramic coating) can be added to the inner wall to adapt to high-wear powder. The advantage is that the inner wall has high precision, which can ensure the regular forming of the outer wall of the sintering tube, and at the same time provide external limit for the powder, which helps to achieve radial layering.

[0055] The second mold 2 is located on the axis of the PE sintered tube and is used to support the inner wall of the PE sintered tube.

[0056] The second mold 2 is a solid rod-shaped or hollow structure, made of the same material as the first mold 1, with an outer diameter 10-40mm smaller than the inner wall of the first mold 1 (corresponding to a sintering tube wall thickness of 5-20mm). The surface is polished (roughness Ra≤0.4μm), and both ends extend outwards from the outer side of the seal to form a precision-machined connecting shaft section with a diameter of 20-30mm. The connection method is that both ends are positioned with the seal via deep groove ball bearings, and the ends are connected to the vibration motor via a coupling. Optionally, a keyway structure can be added to the shaft section to improve the connection stability with the coupling. The advantage is high vibration transmission efficiency, which can uniformly radiate high-frequency vibration to the powder while avoiding powder adhesion and ensuring a smooth inner wall of the sintering tube.

[0057] The axes of the first mold 1 and the second mold 2 coincide, and the first mold 1 and the second mold 2 cooperate to form a closed space, or form a closed space by combining sealing elements.

[0058] The axis alignment is calibrated by the positioning sleeve built into the seal (coaxiality error ≤ 0.1mm); there are two sealing methods: one is high-precision bonding (the inner wall of the first mold 1 is tightly bonded to the seal and the outer wall of the second mold 2, with a gap ≤ 0.02mm), and the other is to use a seal (fluororubber sealing ring + graphite gasket) for auxiliary sealing; the choice of sealing method is based on the sintering pressure requirements. In low-pressure conditions, bonding alone is sufficient, while in high-pressure / atmosphere protection conditions, a seal is required; the advantages are that it ensures no leakage after powder filling, isolates air during sintering to avoid oxidation of PE powder, and maintains the stability of the mold structure during vibration to prevent axis deviation.

[0059] In some embodiments, the seal includes: a first seal 3.

[0060] The first sealing element 3 is used to seal one end of the first mold 1 and the second mold 2. The first sealing element 3 is a disc-shaped detachable end cap made of stainless steel, with an annular positioning groove (embedded with a deep groove ball bearing, adapted to the shaft section of the second mold 2) and an annular sealing groove (filled with a fluororubber sealing ring) on ​​the inner side; the connection method is to fix it to the end face of the first mold 1 and the shaft section of the second mold 2 through the first fastener 5; optionally, the end cap can be integrated with the sealing cover 13 of the feed port 11 to simplify the structure; the advantage is that it has both sealing and positioning functions, which not only prevents powder leakage and air entry, but also ensures the coaxiality of the second mold 2 when it vibrates, and reduces friction loss.

[0061] In some embodiments, the seal further includes a second seal 4.

[0062] The second sealing element 4 is used to seal the other end of the first mold 1 and the second mold 2. The structure and material of the second sealing element 4 are completely the same as those of the first sealing element 3, except that the installation position is at the other end of the mold, and it is symmetrically arranged with the first sealing element 3. The connection method is to fix it with the second fastener 6, which together with the first sealing element 3 forms a fully enclosed space. Optionally, a pressure relief hole (with a miniature one-way valve) can be added to the second sealing element 4 to balance the pressure in the cavity during sintering. The advantages are that the symmetrical sealing makes the mold uniformly stressed, and there is no off-center load during vibration. At the same time, the fully enclosed design is suitable for atmosphere protection sintering, improving product consistency.

[0063] In some embodiments, it further includes: a first fastener 5.

[0064] The first fastener 5 is formed in the first mold 1, the second mold 2, or the first seal 3, or connected to the first mold 1, the second mold 2, or the first seal 3;

[0065] The first fastener 5 is specifically a bolt, clip, or pin, with three formation / connection options: one is integral molding (e.g., the end face of the first mold 1 is integrally cast into a bolt column), the second is detachable connection (e.g., the bolt passes through the seal and connects to the threaded hole of the mold), and the third is connected to the seal (e.g., the clip is fixed to the seal and engages with the mold groove). For high-frequency vibration conditions, anti-loosening bolts are preferred, while clips can be used for small molds. The advantages are a firm connection, no loosening during vibration, convenient disassembly and assembly, and suitability for rapid sealing and demolding during mass production.

[0066] The first fastener 5 is used to fix the first seal 3 to the first mold 1 and the second mold 2 to form a sealed space. The fixing method is as follows: when fastened with bolts, the inner sealing ring of the seal is deformed by squeezing and filling the gap; when fixed with snaps / pins, the seal is positioned by mechanical engagement and seals with the sealing ring; optional, a spring washer can be added to further improve the anti-loosening effect; the advantages are reliable sealing performance after fastening, resistance to high frequency vibration and high sintering temperature (the sealing ring temperature resistance is ≤250℃), while ensuring the structural rigidity of the mold assembly and avoiding vibration deformation.

[0067] In some embodiments, it further includes a second fastener 6.

[0068] The second fastener 6 is formed in the first mold 1, the second mold 2, or the second seal 4, or connected to the first mold 1, the second mold 2, or the second seal 4.

[0069] The second fastener 6 has the same structure and type as the first fastener 5, except that it is located on the opposite side of the first fastener 5 and is arranged symmetrically with the first fastener 5. The formation / connection is the same as the first fastener 5, and bolts, clips, and pins are optional. Alternatively, it can be of a different type than the first fastener 5 (such as bolts on one end and clips on the other end), which takes into account both stability and disassembly efficiency. Its advantage is that symmetrical fastening makes the force on both ends of the mold even, avoids leakage caused by the displacement of the seal, and is also compatible with different mold sizes, making it highly versatile.

[0070] The second fastener 6 is located on the opposite side of the first fastener 5, and works with the first fastener 5 to fix the second seal 4 to the first mold 1 and the second mold 2, and works with the first seal 3 to form a sealed space.

[0071] The fitting method is to simultaneously tighten the fasteners at both ends, so that the first and second sealing parts 4 press against both ends of the mold respectively, and squeeze the sealing ring to form a fully enclosed cavity; optional method is to use diagonal tightening to avoid uneven force on the sealing parts; the advantage is that the sealed space has strong integrity, and it can prevent powder leakage, air entry or protective gas loss during filling, vibration or sintering processes, while improving the overall vibration stability of the mold and ensuring the layering accuracy.

[0072] In some embodiments, the vibration assembly includes a first vibration motor 7.

[0073] The first vibration motor 7 is connected to the axial end of the second mold 2. The first vibration motor 7 is a high-frequency electromagnetic vibration motor with a power of 1.5-5.5kW, an adjustable frequency of 200-500Hz, and an amplitude of 0.1-0.5mm. The connection method is to connect it to the shaft section of the second mold 2 through a plum blossom-shaped flexible coupling, and the motor is fixed on the vibration bracket through an adjustable motor base. Optionally, the motor can be equipped with a frequency feedback module to monitor vibration parameters in real time. The advantage is that the vibration energy transmission loss is small, and it can accurately drive the second mold 2 to vibrate. At the same time, the motor is independently fixed to avoid the vibration spreading to surrounding equipment.

[0074] The first vibration motor 7 is used to drive the second mold 2 to vibrate at high frequency, causing the ultra-high molecular weight polyethylene powder inside the mold to separate into layers according to particle size. The working principle is that the motor outputs high-frequency vibration, which is transmitted to the second mold 2 through a coupling. The second mold 2 radiates the vibration to the powder, and the layering is achieved by utilizing the difference in inertial force of the particles. Optionally, the vibration frequency can be adjusted by the control module to adapt to powders of different particle sizes. The advantages are that the vibration is highly targeted, the energy is concentrated on the powder, the layering efficiency is high, the effect is uniform, and compared with driving the entire mold to vibrate, the energy consumption is lower and the wear is less.

[0075] In some embodiments, the vibration assembly further includes a second vibration motor 8.

[0076] The first vibration motor 7 is connected to the other end of the second mold 2 in the axial direction; the second vibration motor 8 has the same specifications and material as the first vibration motor 7 and is symmetrically installed on the other end of the second mold 2; the connection method is also to be connected by a plum blossom type flexible coupling, and the motor base and the first vibration motor 7 base are symmetrically fixed on the bracket; optionally, the motor power can be adjusted according to the mold length, and a high-power motor is selected for long molds (≥2 meters); the advantage is that the dual motor drive makes the vibration of the second mold 2 more uniform, without end vibration attenuation, ensuring the consistency of powder layering in the long mold.

[0077] The second vibration motor 8 and the first vibration motor 7 move at the same frequency through a control module, driving the second mold 2 to vibrate at high frequency, causing the ultra-high molecular weight polyethylene powder inside the mold to stratify according to particle size. The same frequency movement is achieved by synchronously adjusting the motor frequency and phase through the control module to ensure that the vibration direction and amplitude are completely consistent. Optional features include unidirectional or reverse vibration (unidirectional vibration is preferred to improve the stratification effect), and the ability to switch between single / dual motor modes according to stratification requirements. The advantage is a significant improvement in vibration stability, avoiding resonance or vibration cancellation caused by different frequencies of the two motors, ensuring precise stratification of the powder according to particle size, and adapting to the stratification requirements of different lengths and different powders, offering high flexibility.

[0078] like Figure 2As shown, in some embodiments, the coupling includes a first coupling 9 and a second coupling 10, used to connect the mold and the vibration assembly, and to transmit the high-frequency vibration of the vibration assembly to the mold. The coupling is a plum-shaped flexible coupling, the elastomer is made of polyurethane (Shore hardness 85-90D), and both ends are connected to the output shaft of the vibration motor and the shaft segment of the second mold 2 respectively through keyways or set screws; optional options include metal flexible couplings (suitable for high vibration intensity conditions) or nylon couplings (suitable for low noise conditions); the advantages are that it can compensate for the small coaxiality deviation (≤0.05mm) between the motor and the second mold 2, buffer vibration impact, avoid shaft wear and motor damage caused by rigid connection, and efficiently transmit high-frequency vibration with a loss ≤5%.

[0079] like Figure 3 As shown, in some embodiments, it also includes: a feed inlet 11.

[0080] The feed port 11 is formed in or connected to the first mold 1; the feed port 11 is a circular through hole with a diameter of 30-50mm, and is opened in the upper middle part of the side wall of the first mold 1; there are two ways to form it: one is integral molding (directly opened during mold processing), and the other is detachable connection (connected to the mold by flange welding or thread); multiple feed ports 11 (≤2) can be set as an option to adapt to rapid filling; the advantages are convenient feeding, which can be matched with various feeding methods such as spiral, gravity, and pressure; the integral molding structure has good sealing performance; the detachable type is easy to maintain and clean, and it is suitable for different mass production scenarios.

[0081] The feed inlet 11 is equipped with a matching sealing cap 13. The feed inlet 11 is used to add ultra-high molecular weight polyethylene powder of different particle sizes into the mold, and the sealing cap 13 is used to seal the feed inlet 11. The sealing cap 13 is a stainless steel disc with a sealing groove on the inner side (for installing fluororubber sealing rings or graphite gaskets). It is fixed to the flange of the feed inlet 11 by bolts or clips. The feed inlet 11 can be used to add mixed powder or to add powder in layers (mixed powder is preferred to simplify operation). The sealing method is to squeeze the sealing ring to fill the gap after the cap is closed. Optionally, the sealing cap 13 can be equipped with a transparent observation window for easy inspection of the filling status. The advantages are reliable sealing after feeding, preventing powder leakage or air entry during vibration or sintering, adaptability to different feeding methods, and easy disassembly and assembly of the sealing cap 13 without affecting the overall sealing performance.

[0082] In some embodiments, the sealing cap 13 can be combined with the first seal 3 or the second seal 4. There are two ways to combine them: one is to integrate it with the first seal 3 (the sealing cap 13 is integrated with the first end cap and fixed by a set of fasteners), and the other is to integrate it with the second seal 4. Optionally, in the case of an integrated design, a feeding channel can be integrated on the sealing cap 13 to simplify the structure. The advantages are to reduce the number of sealing points, reduce the risk of leakage, simplify the disassembly and assembly process, improve the efficiency of mass production, save mold space, and make the structure more compact.

[0083] In some embodiments, it further includes: a filler 12.

[0084] The filler 12 is used to level the ultra-high molecular weight polyethylene powder in the mold. The filler 12 is specifically a pusher type, scraper type, or spiral structure, and the material is nylon (for scratch-resistant molds). Its function is to scrape and compact the powder after filling, so that the powder height is level with the feed inlet 11, and the density is controlled at 0.8-1.0 g / cm³. The filler 12 type can be selected according to the feeding method (spiral feed with spiral filler 12, manual feed with pusher filler 12). The advantages are to avoid local accumulation or voids of powder, ensure uniform force on the powder during vibration stratification, improve the consistency of the sintering tube wall thickness, enhance the powder density, and reduce shrinkage deformation after sintering.

[0085] The filler 12 is formed on the sealing cap 13, connected to the sealing cap 13, or coupled to the inlet 11. There are three connection options: 1) integral molding (the filler 12 and the sealing cap 13 are integrated, and filling is completed simultaneously when the cap is closed); 2) detachable connection (the filler 12 is fixed to the sealing cap 13 by threads or snaps and can be replaced separately); 3) coupling to the inlet 11 (the filler 12 is embedded in the groove of the inlet 11 and positioned by the inlet 11). Optionally, the filler 12 can be equipped with a flexible end to avoid damaging the inner wall of the mold. The advantages are adaptability to different operational needs, simplification of the process with integral molding, ease of maintenance and replacement with detachable parts, precise positioning with coupled parts, good filling effect, and no impact on the sealing performance of the inlet 11, ensuring the integrity of the overall structure.

[0086] like Figure 4 As shown, a manufacturing process for an asymmetric structure microfiltration PE sintered tube includes the following steps:

[0087] S1. Material preparation: Fill the mold with ultra-high molecular weight polyethylene powder of different particle sizes;

[0088] S2. Vibration stratification: The mold includes an outer cylinder and a central core rod. The two ends of the core rod are connected to a high-frequency vibration motor. Through high-frequency vibration, the ultra-high molecular weight polyethylene powder in the mold is stratified according to the particle size. Large PE particles form the inner layer, and small PE particles form the outer layer.

[0089] S3. Sintering: The mold filled with PE powder is placed in a sintering furnace. At the set temperature, the surface of the PE particles begins to melt, and the melted parts between the PE particles form a connection. After cooling, the mold is demolded to form a sintered tube with a large inner channel and a dense small pore layer on the outside.

[0090] In step S1, ultra-high molecular weight polyethylene powder with a molecular weight of 3-5 million is selected and divided into two groups according to particle size: inner layer of large particles (80-120 mesh, particle size 125-180μm) and outer layer of small particles (200-300 mesh, particle size 50-75μm). The powder needs to be pretreated: dried at 80℃ for 2-4 hours to remove moisture (moisture content ≤0.1%) to avoid the formation of bubbles after sintering; after drying, 0.2-0.5% dispersant (zinc stearate) is added to prevent particle agglomeration.

[0091] In step S2, after the mold assembly is coaxially fixed, pre-treated powder is filled using any feeding method. During filling, a 100Hz low-frequency vibration is activated to assist in material distribution and prevent local accumulation. After filling is completed and the feed inlet 11 and both ends of the mold are sealed, dual high-frequency vibration motors are started, driving the second mold 2 to vibrate in the same direction and at the same frequency (300-400Hz, amplitude 0.2-0.3mm) for 20-40 minutes via a coupling. Utilizing the vibration sieving effect, large powder particles aggregate towards the axis due to strong inertial force, forming a coarse-pore inner layer, while small particles diffuse outwards, forming a fine-pore outer layer, creating a continuous gradient structure. This solves the problem of disordered layering in traditional methods and lays the foundation for seamless fusion during subsequent sintering.

[0092] In step S3, the sealed mold is placed into a protective atmosphere sintering furnace. After nitrogen is introduced to replace the air, the temperature is raised according to the process. Preheating is performed at 10℃ / min to 180℃ to remove residual moisture and air; holding at 180-190℃ for 1-2 hours allows the surface of the PE particles to melt and form a thin molten film, while the interior remains solid; holding at 200-210℃ strengthens the bonding, forming a strong bond bridge. Nitrogen is used for slight positive pressure protection throughout the process, with hot air circulation for temperature control. After sintering, gradient cooling is performed, first naturally cooling to 150℃, then forced cooling to room temperature with nitrogen to avoid internal stress and pore deformation, ultimately obtaining an asymmetric sintered tube with both precision and throughput.

[0093] This invention efficiently solves the problem of preparing asymmetric microfiltration PE sintered tubes by adapting the production equipment and processes, significantly improving overall performance and mass production feasibility. The device uses coaxial first mold 1 and second mold 2, along with sealing components and fasteners, to form a reliable sealed space. Driven by dual high-frequency vibration motors via couplings and precise vibration parameters, it achieves uniform stratification of powder according to particle size, solving the problems of disordered stratification and discontinuous gradients in traditional methods, ensuring seamless fusion between layers without the risk of detachment. Pre-treatment removes moisture and agglomeration, while nitrogen protection and gradient temperature control during sintering ensure that only the particle surface melts. The inner coarse pores guarantee throughput, while the outer fine pores improve precision. The overall structure is simple and easy to assemble and disassemble, with a standardized process flow, adaptable to various feeding methods. Compared to traditional technologies, the product's filtration efficiency is improved, dirt holding capacity is doubled, production efficiency is increased, costs are reduced, and the structure is stable with a long service life, meeting the high-precision filtration needs of various scenarios.

[0094] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An apparatus for producing asymmetrically structured microfiltration PE sintered tubes, characterized in that, The utility model relates to a kind of PE sintering tube and its manufacturing method, comprising: Mold, the mold is used to fill the powder of different particle sizes of ultra-high molecular weight polyethylene, and is put into sintering furnace and is sintered into PE sintering tube; Vibration assembly, one end or both ends of the mold axis is connected, the vibration assembly is used to make the ultra-high molecular weight polyethylene powder in the mold stratification by particle size by high-frequency vibration; Wherein, large particle ultra-high molecular weight polyethylene powder moves to the formation of inner layer along the axis, small particle ultra-high molecular weight polyethylene powder moves away from the axis and forms outer layer, and after vibration is completed, it is put into sintering furnace and is sintered into PE sintering tube.

2. The apparatus for producing asymmetrically structured microfiltration PE sintered tube according to claim 1, characterized in that, The mold comprises: First mold (1), the first mold (1) is away from the axis of PE sintering tube, for supporting the outer wall of PE sintering tube; Second mold (2), the second mold (2) is located at the axis position of PE sintering tube, for supporting the inner wall of PE sintering tube; The axis of the first mold (1) and the second mold (2) coincides, and the first mold (1) and the second mold (2) form a closed space in cooperation, or form a closed space by combining sealing element.

3. The apparatus for producing asymmetrically structured microfiltration PE sintered tube according to claim 2, characterized in that, The sealing element comprises: First sealing element (3), the first sealing element (3) is used to seal one end of the first mold (1) and the second mold (2).

4. The apparatus for producing asymmetrically structured microfiltration PE sintered tube according to claim 3, characterized in that, The sealing element further comprises: Second sealing element (4), the second sealing element (4) is used to seal the other end of the first mold (1) and the second mold (2).

5. The apparatus for producing asymmetrically structured microfiltration PE sintered tube according to claim 4, characterized in that, Further comprising: First fastener (5), the first fastener (5) is formed in the first mold (1), the second mold (2) or the first sealing element (3), or connected to the first mold (1), or connected to the second mold (2), or connected to the first sealing element (3); The first fastener (5) is used to fix the first sealing element (3) with the first mold (1), the second mold (2) and form a closed space.

6. The apparatus for producing asymmetrically structured microfiltration PE sintered tube according to claim 5, characterized in that, Further comprising: Second fastener (6), the second fastener (6) is formed in the first mold (1), the second mold (2) or the second sealing element (4), or connected to the first mold (1), or connected to the second mold (2), or connected to the second sealing element (4); The second fastener (6) is located on the opposite side of the first fastener (5), and cooperates with the first fastener (5) to fix the second sealing element (4) with the first mold (1), the second mold (2) and cooperate with the first sealing element (3) to form a closed space.

7. The apparatus for producing asymmetrically structured microfiltration PE sintered tube according to claim 2, characterized in that, The vibration assembly comprises: First vibration motor (7), the first vibration motor (7) is connected with the end of the second mold (2) in axial direction; The first vibration motor (7) is used to make the ultra-high molecular weight polyethylene powder in the mold stratification by particle size by driving the second mold (2) high-frequency vibration.

8. The apparatus for producing asymmetrically structured microfiltration PE sintered tube according to claim 7, characterized in that, The vibration assembly further comprises: Second vibration motor (8), the second vibration motor (8) is connected with the other end of the second mold (2) in axial direction; Wherein, the second vibration motor (8) and the first vibration motor (7) realize the same frequency motion through control module, and drive the second mold (2) high-frequency vibration, so that the ultra-high molecular weight polyethylene powder in the mold stratification by particle size.

9. The apparatus for producing asymmetrically structured microfiltration PE sintered tube according to claim 2, characterized in that, Further comprising: A coupling is used to connect the mold and the vibration assembly, and to transmit the high-frequency vibration of the vibration assembly to the mold. An inlet (11) is formed in or connected to the first mold (1); A sealing cover (13) is arranged on the inlet (11) to seal the inlet (11) and add the ultra-high molecular weight polyethylene powder with different particle sizes into the mold. The sealing cover (13) can be combined with the first sealing member (3) or the second sealing member (4). A filler (12) is used to make the ultra-high molecular weight polyethylene powder in the mold flush. The filler (12) is formed in the sealing cover (13), or connected to the sealing cover (13), or coupled with the inlet (11).

10. A process for the production of asymmetrically structured microfiltration PE sintered tubes, characterized by, The method comprises the following steps: S1, preparing materials: filling the ultra-high molecular weight polyethylene powder with different particle sizes into the mold; S2, vibration layering: the mold comprises a cylinder with an outer wall and a core rod in the center, the core rod is connected to the high-frequency vibration motor at both ends, the ultra-high molecular weight polyethylene powder in the mold is layered according to the particle size by high-frequency vibration, wherein the large particle PE material forms the inner layer and the small particle PE material forms the outer layer; S3, sintering: the mold filled with PE powder is put into a sintering furnace, the surface of PE particles starts to melt at a set temperature, the melted part between the PE particles forms a connection, and after cooling, the sintered tube with an inner layer of large pores and an outer layer of dense small pores is formed.

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