Cylindrical multifunctional filtering structure and production method thereof

Abstract

The invention discloses a cylindrical multifunctional filtering structure and a production method thereof, which can simplify the process and enrich the functions of a filter bag, and comprises two adjacent cylindrical filter bag sections and a connecting assembly for connecting the two filter bag sections, each filter bag section comprises a hole pipe, a catalytic membrane and a metal membrane which are arranged layer by layer from inside to outside, and a solid catalyst is attached to the catalytic membrane; the connecting assembly comprises a first end pipe joint and a second end pipe joint of which the ends are connected; a first reducing section is arranged at one end part of the first end pipe joint, and a second reducing section and a third reducing section are respectively arranged at two end parts of the second end pipe joint; the first reducing section and the third reducing section are respectively inserted into the end parts of the hole pipes of the two filter bag sections, and the second reducing section is inserted into the other end part of the first end pipe joint; the inner walls of the end parts of the metal films of the two filter bag sections are respectively welded with the circumferential surfaces of the first end pipe joint and the second end pipe joint; and the end surfaces of the hole pipes of the two filter bag sections are respectively welded with the reducing inclined surfaces of the first reducing section and the third reducing section.

Description

Technical Field

[0001] This invention relates to the field of metal filter bag technology, and in particular to a cylindrical multifunctional filter structure and its manufacturing method. Background Technology

[0002] Metal filter bags are a type of filter material used for dust removal in high-temperature flue gas. They are primarily made of metallic materials such as metal fibers or metal alloy powders, and are produced through pressing and sintering to form a porous intermetallic compound filter material. This material can replace non-metallic filter bags that are not heat-resistant, possessing characteristics such as high temperature resistance, resistance to strong acids and alkalis, high mechanical strength, and a certain degree of flexibility. It can solve the problem of high-precision interception of dust particles in high-temperature industrial flue gas. They are commonly used in industries such as metallurgy, coal combustion, alumina, steel, cement, glass, non-ferrous metallurgy, and waste incineration to achieve dust removal and gas-solid separation in high-temperature environments.

[0003] Metal filter bags generally consist of an inner perforated tube (a) and a metal membrane (2) covering the surface of the perforated tube (a). Because metal filter bags have a certain degree of flexibility, when the application requires a specific length, connectors are needed to join multiple sections of the metal filter bag into a complete filter bag product to avoid insufficient support strength. See also... Figure 1 In the prior art, a filter bag section is composed of a perforated tube 1 of a certain length and a metal membrane 2, and a first end pipe joint 3 and a second end pipe joint 4 made of metal are provided between adjacent filter bag sections. The first end pipe joint 3 and the second end pipe joint 4 are respectively fixedly connected to the corresponding filter bag sections, and the first end pipe joint 3 and the second end pipe joint 4 are fixedly connected by riveting or welding. Among them, the left end tube 1 and the first end tube connector 3, the first end tube connector 3 and the second end tube connector 4, and the second end tube connector 4 and the right end tube 1' are all connected by a stepped structure. The disadvantages are: (1) The first end tube connector 3 and the second end tube connector 4 are machined parts, which are relatively expensive; (2) The first end tube connector 3 and the second end tube connector 4 are difficult to connect with the tubes 1 and 1', and the insertion is troublesome. Moreover, since the thickness of the tubes 1 and 1' is only 0.65-0.70mm, after spiral welding, the roundness of the metal filter bag is greatly deformed and cannot maintain the original circular cross section; (3) The metal filter bag can only intercept dust in the flue gas and cannot purify specific harmful gases in the flue gas. Summary of the Invention

[0004] The purpose of this invention is to provide a cylindrical multifunctional filter structure and its manufacturing method, which solves the problems existing in the prior art, is suitable for flue gas dust removal and purification in high-temperature environments, and simplifies the connection process.

[0005] To achieve the above objectives, one solution of the present invention is: A cylindrical multifunctional filter structure includes two adjacent cylindrical filter bag sections and a connecting assembly for connecting the two filter bag sections. Each filter bag section includes a pore tube, a catalytic membrane, and a metal membrane arranged layer by layer from the inside out, with a solid catalyst attached to the catalytic membrane. The connecting assembly includes a first end connector and a second end connector connected at their ends. One end of the first end connector has a first reduced diameter section, and the two ends of the second end connector have a second reduced diameter section and a third reduced diameter section, respectively. The first and third reduced diameter sections are respectively inserted into the ends of the pore tubes of the two filter bag sections, and the second reduced diameter section is inserted into the other end of the first end connector. The inner walls of the metal membranes of the two filter bag sections are welded to the circumferential surfaces of the first and second end connectors, respectively, and the end faces of the pore tubes of the two filter bag sections are welded to the reduced diameter slopes of the first and third reduced diameter sections, respectively.

[0006] High-temperature resistant sealant is provided between the end face of the catalyst membrane and the peripheral surface of the pore tube.

[0007] The inner wall of the end of the metal film is attached to the circumferential surface of the first end pipe joint or the second end pipe joint, and welding is achieved by circumferential resistance roll welding process.

[0008] The end face of the tube abuts against the reduced diameter slope of the first reduced diameter section or the reduced diameter slope of the third reduced diameter section, and welding is achieved by circumferential laser welding process.

[0009] The end face of the other end of the first end pipe joint abuts against the reduced diameter slope of the second reduced diameter section, and welding is achieved by circumferential laser welding process.

[0010] The thickness of the catalytic membrane is greater than the thickness of the metal membrane, and the pore size of the catalytic membrane is greater than the pore size of the metal membrane.

[0011] The catalytic membrane is made of nickel foam, stainless steel foam, or metal felt.

[0012] The second solution of the present invention is: A method for producing a cylindrical multifunctional filter structure includes the following steps: Step 1: The catalyst membrane is subjected to a slurry-drawing process using a slurry-drawing machine, followed by drying. The catalyst membrane passes sequentially through a slurry-casting mold and a slurry tank of the slurry-drawing machine. The slurry-casting mold contains a slurry containing a solid catalyst. A peristaltic pump is installed between the slurry-casting mold and the slurry tank. The peristaltic pump draws slurry from the slurry tank and pumps it into the slurry-casting mold under high pressure. Step 2: According to the size requirements of the product design, roll up and cut the dried catalyst film with solid catalyst attached. Step 3: First, place the perforated tube onto the air expansion shaft of the roll welding machine; then, stack the catalyst membrane and stainless steel wire mesh sequentially on the worktable of the roll welding machine, leaving welding edges on both sides of the stainless steel wire mesh that extend beyond the sides of the catalyst membrane; start the roll welding machine, and the welding head welds one side of the stainless steel wire mesh onto the perforated tube. Then, the air expansion shaft rolls to make the catalyst membrane cover the perforated tube at least once, and the welding head welds the other side of the welding edge onto the surface of the stainless steel wire mesh. Step 4: Insert the first end pipe connector or the second end pipe connector into the end of the perforated pipe and perform rolling welding; Step 5: Roll the metal film into a cylindrical shape and weld it longitudinally, then fit it onto the circumference of the perforated tube and roll it with the corresponding end tube joint. Step 6: Insert the first end connector of the paired filter bag section into the second end connector and then perform rolling welding.

[0013] In step 1, several stirring rollers are installed in the slurry tank of the slurry pulling machine, and the axial direction of the stirring rollers is parallel to the width direction of the catalyst film.

[0014] In step 1, the grouting mold has a flared opening inside the channel for the catalytic membrane to enter and exit, and rubber sheets are provided on both sides of the flared opening. When the catalytic membrane enters and exits the grouting mold, a dynamic seal is formed between it and the rubber sheets.

[0015] In step 1, grout inlets are provided on both sides of the grouting mold, and both grout inlets are connected to the output end of the peristaltic pump; the grouting mold is provided with two flow-diverting cavities that are respectively connected to the two grout inlets, the two flow-diverting cavities are symmetrically arranged on both sides of the inside of the grouting mold, and each flow-diverting cavity is provided with several flow-diverting ports.

[0016] After adopting the above technical solution, the present invention has the following technical effects: (1) The present invention adopts a dual-membrane filter cartridge structure of metal membrane and catalytic membrane, which can filter particulate dust in flue gas and catalytically treat harmful gases in flue gas. In particular, the solid catalyst attached to the catalytic membrane 5 in high temperature environment can react with harmful gases in a very short time, transforming them into gases with lower or even harmless levels of harm, thus achieving simultaneous dust removal and purification of flue gas. It has rich functions and can save material and equipment costs compared with the method of using multiple devices for segmented processing in the prior art. (2) The catalytic membrane is located inside the metal membrane. The solid catalyst is not easy to fall off under the wrapping of the two membranes, and the catalytic effect is stable and the effective time is long. (3) Regarding the connection method of adjacent filter bag sections, the present invention adopts the narrowing insertion method. The narrowing section of the end tube joint can be formed by processes such as rolling, which makes the production process simple and low-cost. It also reduces the difficulty of insertion during assembly and ensures a gapless fit between the perforated tube and the narrowing section of the end tube joint, which can prevent flue gas dust and harmful gases from escaping from the gap. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the existing technology; Figure 2 This is a schematic diagram of a specific embodiment of the present invention; Figure 3 This is a schematic diagram of the slurry-drawing process for the catalytic membrane according to the present invention; Figure 4 This is an enlarged view of a portion of the structure of the pulverizing machine used in this invention; Figure 5 This is a schematic diagram illustrating the assembly of the catalytic membrane according to the present invention; Explanation of icon numbers: 1-Perforated tube; 2-Metal membrane; 3-First end pipe joint; 31-First diameter reduction section; 311-Diameter reduction slope; 4-Second end pipe joint; 41-Second diameter reduction section; 411-Diameter reduction slope; 42-Third diameter reduction section; 421-Diameter reduction slope; 5-Catalytic membrane; 6-High temperature resistant sealant; 7-Stainless steel wire mesh; 71-Welding edge; 10-Slurry pulling machine; 101-Grouting mold; 1011-Channel opening; 1012-Flanged opening; 1013-Rubber sheet; 1014-Slurry inlet; 1015-Diverter chamber; 1016-Diverter port; 102-Slurry tank; 103-Peristaltic pump; 104-Agitating roller; 20-Air expansion shaft; 30-Workbench; 40-Welding head. Detailed Implementation

[0018] To further explain the technical solution of the present invention, the present invention will be described in detail below through specific embodiments.

[0019] refer to Figure 2 As shown, the present invention discloses a cylindrical multifunctional filter structure, including two adjacent cylindrical filter bag sections and a connecting component for connecting the two filter bag sections. The filter bag section includes a porous tube 1, a catalytic membrane 5 and a metal membrane arranged layer by layer from the inside to the outside. The catalytic membrane 5 is coated with a solid catalyst. The connecting assembly includes a first end connector 3 and a second end connector 4 connected at their ends; one end of the first end connector 3 is provided with a first reduced diameter section 31, and the two ends of the second end connector 4 are respectively provided with a second reduced diameter section 41 and a third reduced diameter section 42; the first reduced diameter section 31 and the third reduced diameter section 42 are respectively inserted into the ends of the perforated tubes 1 of the two filter bag sections, and the second reduced diameter section 41 is inserted into the other end of the first end connector 3. The inner walls of the metal membranes 2 at the ends of the two filter bag sections are welded to the circumferential surfaces of the first end pipe joint 3 and the second end pipe joint 4, respectively. The end faces of the perforated tubes 1 of the two filter bag sections are welded to the diameter reduction slopes 311 and 421 of the first diameter reduction section 31 and the third diameter reduction section 42, respectively.

[0020] Through the above scheme, the present invention adopts a dual-membrane filter cartridge structure of metal membrane 2 and catalytic membrane 5, which can not only filter particulate dust in flue gas, but also catalytically treat harmful gases in flue gas. In particular, the solid catalyst attached to the catalytic membrane 5 in a high-temperature environment can react with harmful gases in a very short time, transforming them into gases with lower harmful levels or even harmless gases, thus achieving simultaneous dust removal and purification of flue gas. It has rich functions and can save material and equipment costs compared with the existing technology that uses multiple devices for segmented processing. The catalytic membrane 5 is located inside the metal membrane 2, and the solid catalyst is not easy to fall off under the wrapping of two membranes, resulting in stable catalytic effect and long effective time. In terms of the connection method of adjacent filter bag sections, the present invention adopts a narrow-mouth insertion type. The narrow-diameter section of the end tube joint can be formed by rolling and other processes, which simplifies the production process, reduces the difficulty of insertion during assembly, and ensures a gapless fit between the perforated tube 1 and the narrow-diameter section of the end tube joint, which can prevent flue gas dust and harmful gases from escaping from the gaps.

[0021] The following illustrates specific embodiments of the present invention.

[0022] The thickness of the catalytic membrane 5 is greater than that of the metal membrane 2, and the pore size of the catalytic membrane 5 is greater than that of the metal membrane 2, which can increase the catalytic time of the catalytic membrane 5 and improve the efficiency of purifying harmful gases.

[0023] High-temperature resistant sealant 6 is provided between the end face of the catalyst membrane 5 and the peripheral surface of the pore tube 1 to achieve end sealing of the catalyst membrane 5 and prevent harmful gases from escaping.

[0024] The inner wall of the end of the aforementioned metal film 2 is attached to the circumferential surface of the first end pipe joint 3 or the second end pipe joint 4, and welding is achieved by circumferential resistance roll welding process.

[0025] The end face of the aforementioned tube 1 abuts against the reduced diameter slope 311 of the first reduced diameter section 31 or the reduced diameter slope 421 of the third reduced diameter section 42, and is welded using a circumferential laser welding process.

[0026] The end face of the other end of the first end pipe joint 3 abuts against the reduced diameter inclined surface 411 of the second reduced diameter section 41, and welding is achieved by circumferential laser welding process.

[0027] The catalyst membrane 5 mentioned above is made of corrosion-resistant metal materials such as foamed nickel, foamed stainless steel, and metal felt, and has a three-dimensional honeycomb mesh structure to ensure sufficient air permeability and flexibility. The solid catalyst is more easily squeezed into the mesh structure and combined with the mesh structure. It is wrapped by the ribs of the mesh structure to improve the adhesion time of the solid catalyst and thus ensure the effective life of the product.

[0028] The solid catalyst attached to the aforementioned catalytic membrane 5 is a type of catalyst existing in the solid phase, which can be selected according to different application scenarios (for different flue gas compositions). Solid catalysts are classified according to the type of active material, including: ① Single-component metal oxides: These catalysts include oxides of alkali metals, alkaline earth metals, and rare metals, such as ThO2, ZrO2, ZnO2, TiO2, etc. ② Metal catalysts: Composed of a single metal or metal alloy, such as platinum, palladium and nickel. These catalysts are widely used in reactions such as hydrogenation, oxidation and dehydrogenation. ③ Metal oxide catalysts: composed of metal oxides or mixtures of metal oxides, such as alumina, silicon dioxide and titanium dioxide, which are often used in oxidation, reduction and decomposition reactions; ④ Zeolite catalysts: composed of microporous crystalline materials, such as ZSM-5 and Y-zeolite, which are widely used in cracking, isomerization and alkylation reactions; ⑤ Supported catalysts: These consist of metals or metal oxides deposited on high surface area support materials, such as platinum supported on alumina and palladium supported on carbon. These catalysts are used for a variety of reactions such as hydrogenation, oxidation, and reforming. ⑥ Bifunctional catalysts: Catalysts containing two or more active sites with different functions, such as metal acid catalysts and metal base catalysts, are used for reactions such as hydrocracking, hydroisomerization and hydrodesulfurization.

[0029] This invention also discloses a method for producing a cylindrical multifunctional filter structure, comprising the following steps: Step 1, see Figure 3For the catalyst membrane 5, a slurry pulling machine 10 is used to pull the slurry before drying. The catalyst membrane 5 passes sequentially through the slurry mold 101 and the slurry tank 102 of the slurry pulling machine 10. The slurry mold 101 contains a slurry containing a solid catalyst. A peristaltic pump 103 is installed between the slurry mold 101 and the slurry tank 102. The peristaltic pump 103 draws slurry from the slurry tank 102 and pumps it into the slurry mold 101 under high pressure, creating pressure within the slurry in the slurry mold 101. This pressure forces out air from the catalyst membrane 5 passing through the slurry mold 101 and forces the solid catalyst into the three-dimensional honeycomb structure of the catalyst membrane 5, improving the adhesion rate of the solid catalyst. It is understood that the larger the inner cavity of the slurry mold 101, the longer the pressurized slurry is pressed into the catalyst membrane 5, and the higher the adhesion rate of the solid catalyst will be. Step 2: According to the size requirements of the product design, roll up and cut the dried catalyst membrane 5 with the solid catalyst attached. Step 3: Because the catalyst membrane 5 itself is relatively soft and has low strength, and because solid catalysts are attached to its surface and interior, its welding performance is greatly affected. Therefore, traditional metal flexible membrane processing methods cannot be used to assemble the pore tube 1 and the catalyst membrane 5. For this reason, the present invention adopts a new approach, see [link to relevant documentation]. Figure 5 First, place the perforated tube 1 onto the air expansion shaft 20 of the roll welding machine; then, stack the catalyst membrane 5 and the stainless steel wire mesh 7 sequentially on the worktable 30 of the roll welding machine, with welding edges 71 extending beyond the sides of the catalyst membrane 5 on both sides of the stainless steel wire mesh 7; start the roll welding machine, and the welding head 40 welds the welding edge 71 on one side of the stainless steel wire mesh 7 onto the perforated tube 1. Then, the air expansion shaft 20 rolls so that the catalyst membrane 5 covers the perforated tube 1 at least once, and the welding head 40 welds the welding edge 71 on the other side onto the surface of the stainless steel wire mesh 7. Step 4: Insert the first end pipe connector 3 or the second end pipe connector 4 into the end of the bore pipe 1 and perform rolling welding; Step 5: Roll the metal film 2 into a cylindrical shape and weld it longitudinally, then fit it onto the circumference of the perforated tube 1 and roll it with the corresponding end tube joint. Step 6: Insert the first end connector 3 and the second end connector 4 of the paired filter bag sections and then perform rolling welding.

[0030] In step 1 above, several stirring rollers 104 are installed in the slurry tank 102 of the slurry puller 10, and the axial direction of the stirring rollers 104 is parallel to the width direction of the catalyst film 5. By setting the stirring rollers 104, the solid catalyst in the slurry tank 102 can be distributed more evenly in the slurry.

[0031] See Figure 4In step 1 above, the grouting mold 101 has a flared opening 1012 inside the channel 1011 for the catalytic membrane 5 to enter and exit, and rubber sheets 1013 are provided on both sides of the flared opening 1012. When the catalytic membrane 5 enters and exits the grouting mold 101, a dynamic seal is formed between it and the rubber sheets 1013. By setting the rubber sheets 1013, the following functions are achieved: ① The catalytic membrane can pass through effectively without damaging the product; ② The grout inside the grouting mold 101 can be effectively pressurized; ③ When the grout pressure inside the mold is too high, the rubber sheets 1013 will bend outward under pressure due to the clearance provided by the flared opening 1012, making the gap between the two rubber sheets 1013 larger, and the grout will be discharged more quickly to reduce pressure; ④ It acts like a scraper, effectively controlling the thickness of the grout at the outlet of the grouting mold 101.

[0032] Meanwhile, in step 1 above, grouting mold 101 has slurry inlets 1014 on both sides, and both slurry inlets 1014 are connected to the output end of peristaltic pump 103. Grouting mold 101 has two flow distribution chambers 1015, each connected to one of the two slurry inlets 1014. The two flow distribution chambers 1015 are symmetrically arranged on both sides of the interior of grouting mold 101, and each flow distribution chamber 1015 has several flow outlets 1016. By setting the flow distribution chambers 1015, the flow rate is distributed, ensuring that the pumped slurry is not directly sprayed onto the catalyst membrane 5, and that the slurry flows evenly in different directions within grouting mold 101, ensuring that high pressure is distributed at all locations within grouting mold 101.

[0033] The above embodiments and figures are not intended to limit the product form and style of the present invention. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of the present invention.

Claims

1. A cylindrical multifunctional filter structure, characterized in that: two adjacent cylindrical filter bag sections and a connecting assembly for connecting the two filter bag sections; the filter bag section comprises, from inside to outside, a hole tube, a catalytic membrane and a metal membrane, and the catalytic membrane is attached with solid catalyst; the connecting assembly comprises a first end tube joint and a second end tube joint connected at their ends; one end of the first end tube joint is provided with a first reduced diameter section, and the two ends of the second end tube joint are respectively provided with a second reduced diameter section and a third reduced diameter section; the first reduced diameter section and the third reduced diameter section are respectively inserted into the end of the hole tube of the two filter bag sections, and the second reduced diameter section is inserted into the other end of the first end tube joint; the inner wall of the end of the metal membrane of the two filter bag sections is respectively welded to the peripheral surface of the first end tube joint and the second end tube joint, and the end surface of the hole tube is respectively welded to the reduced diameter inclined surface of the first reduced diameter section and the third reduced diameter section. 2.The cylindrical multifunctional filter structure of claim 1, characterized in that: a high-temperature-resistant sealing glue is arranged between the end surface of the catalytic membrane and the peripheral surface of the hole tube. 3.The cylindrical multifunctional filter structure of claim 1, characterized in that: the end inner wall of the metal membrane is attached to the peripheral surface of the first end tube joint or the second end tube joint, and the welding is realized by using a circumferential resistance roll welding process. 4.The cylindrical multifunctional filter structure of claim 1, characterized in that: the end surface of the hole tube is abutted to the reduced diameter inclined surface of the first reduced diameter section or the reduced diameter inclined surface of the third reduced diameter section, and the welding is realized by using a circumferential laser welding process. 5.The cylindrical multifunctional filter structure of claim 1, characterized in that: the end surface of the other end of the first end tube joint is abutted to the reduced diameter inclined surface of the second reduced diameter section, and the welding is realized by using a circumferential laser welding process. 6.The cylindrical multifunctional filter structure of claim 1, characterized in that: the thickness of the catalytic membrane is greater than the thickness of the metal membrane, and the pore size of the catalytic membrane is greater than the pore size of the metal membrane. 7.The cylindrical multifunctional filter structure of claim 1, characterized in that: the catalytic membrane is selected from foamed nickel, foamed stainless steel or metal felt. comprising the following steps: Step 1, for the catalytic membrane, after using a pulper for pulping treatment and then drying treatment, the catalytic membrane sequentially passes through a grouting die and a slurry tank of the pulper, the grouting die contains slurry containing solid catalyst, a peristaltic pump is arranged between the grouting die and the slurry tank, and the peristaltic pump extracts slurry from the slurry tank and pumps it into the grouting die under high pressure; Step 2, according to the size requirements of product design, the catalytic membrane attached with solid catalyst after drying is wound and cut off. ​ ​ ​ ​ ​ ​ ​ 8. A method of producing the cylindrical multifunctional filter structure according to any one of claims 1 to 7, characterized by ​ ​ ​ Step 3, first, the hole pipe sleeve is placed on the air expansion shaft of the seam welder; then the catalytic membrane and the stainless steel wire mesh are stacked in sequence on the workbench of the seam welder, the two sides of the stainless steel wire mesh are reserved with welding edges beyond the side edges of the catalytic membrane; start the seam welder, the welding head welds the welding edge on one side of the stainless steel wire mesh on the hole pipe, then the air expansion shaft rolls to make the catalytic membrane cover the hole pipe at least one turn, and the welding head welds the welding edge on the other side on the surface of the stainless steel wire mesh; Step 4, the first end pipe joint or the second end pipe joint is inserted into the end of the hole pipe and is roll welded; Step 5, the metal film is rolled into a cylindrical shape and longitudinally welded, then is sleeved on the peripheral surface of the hole pipe and is roll welded with the corresponding end pipe joint; Step 6, the first end pipe joint and the second end pipe joint of the paired filter bag section are inserted and roll welded.

9. The production method of the cylindrical multifunctional filter structure according to claim 8, characterized in that: In step 1, a plurality of stirring rollers are installed in the pulp tank of the pulp drawing machine, and the axis direction of the stirring rollers is parallel to the width direction of the catalytic membrane.

10. The production method of the cylindrical multifunctional filter structure according to claim 8, characterized in that: In step 1, a trumpet mouth is arranged on the inner side of the channel opening of the grouting mold for the catalytic membrane to enter and exit, and rubber sheets are arranged on both sides of the trumpet mouth, and dynamic sealing is formed between the catalytic membrane and the rubber sheets when the catalytic membrane enters and exits the grouting mold.

11. The production method of the cylindrical multifunctional filter structure according to claim 8, characterized in that: In step 1, pulp inflow openings are arranged on both sides of the grouting mold, and the two pulp inflow openings are in communication with the output end of the peristaltic pump; two shunt cavities are arranged in the grouting mold and are in communication with the two pulp inflow openings respectively, the two shunt cavities are symmetrically arranged on the two sides of the inside of the grouting mold, and each shunt cavity is provided with a plurality of shunt openings.

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