A bottom-pouring casting device and method for large butterfly valve bodies made of ductile iron.

Abstract

This invention relates to a bottom-pouring casting device and method for large butterfly valve bodies made of ductile iron, belonging to the technical field of bottom-pouring casting equipment for ductile iron. It includes a casting mold and a lower sand box. The casting mold is composed of two symmetrically inserted workpiece molds. Each workpiece mold has a horizontal pouring module connected to its outer bottom end via several short rods. Several riser modules are installed on the top of the casting mold. A direct pouring mold column is fixedly installed on the top of each horizontal pouring module at the outer bottom end of the two workpiece molds. This invention, through the precise matching design of the horizontal pouring module, riser module, and direct pouring mold column, constructs a scientifically reasonable dedicated pouring channel, achieving a bottom-to-top sequential solidification effect for the casting. It can efficiently compensate for the thick cross-sections and hot spots of large butterfly valves, effectively eliminating internal defects such as shrinkage cavities and porosity, ensuring a dense and uniform casting structure, and significantly improving the overall forming quality of large butterfly valves.

Description

Technical Field

[0001] This invention relates to the technical field of bottom-pouring casting equipment for ductile iron, specifically to a bottom-pouring casting equipment and method for a large butterfly valve body made of ductile iron. Background Technology

[0002] The large butterfly valve body has a diameter of 4m, a width of 1m, and a wall thickness of 100mm. It is a large-size, heavy, and thick-section ductile iron casting with flanges at both ends, resulting in a complex solidification shrinkage process and highly concentrated heat points, making it extremely difficult to cast. Currently, traditional large valve body castings mostly use conventional sand casting processes, with top-middle pouring and risers often arranged in small numbers or evenly. In addition, the overall size of the parts is large, making it difficult to accurately control the cooling sequence of the casting. The size of the chills, the position and number of risers cannot be precisely matched, and the overall process design is relatively crude, leading to a series of casting defects that make it difficult to meet the stringent requirements of high-pressure sealing conditions and long-term stable operation of large butterfly valves.

[0003] The existing molding molds for butterfly valve castings are large in size and heavy in weight, making mold transportation, hoisting, and on-site relocation difficult, resulting in high equipment transportation costs and low turnover efficiency. Furthermore, to achieve a bottom-up sequential solidification process for the castings, the gating system, risers, chills, and cooling structures need to be meticulously designed and arranged to ensure sufficient feeding in the thick cross-sections and hot spots of the butterfly valve, effectively reducing shrinkage cavities and porosity defects. However, the arrangement of multiple molding auxiliary structures inside the sand box cavity creates a complex internal space with numerous concave and convex components. When workers compact the molding sand inside the sand box after filling, it is difficult to evenly fill all narrow gaps and dead corners of components, resulting in insufficient compaction in some areas. This significantly increases the difficulty of compaction operations, easily leading to problems such as loose sand molds and cavities. During pouring, this can easily cause sand erosion and collapse, increasing the probability of defects such as sand holes and deformation in the castings, thus restricting the finished product qualification rate and production efficiency. To address the aforementioned issues, innovative design based on existing methods is urgently needed. Summary of the Invention

[0004] The purpose of this invention is to provide a bottom-pouring casting device and method for large butterfly valve bodies made of ductile iron, in order to solve the problems mentioned in the background. The technical solution of this invention addresses the problem that the existing technical solutions are too simplistic and provides a solution that is significantly different from the existing technology.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a bottom-pouring casting device and method for a large butterfly valve body made of ductile iron, comprising a casting mold and a lower sand box. The casting mold is composed of two symmetrically inserted workpiece molds. The bottom of each workpiece mold is connected to a horizontal pouring module via several short rods. Several riser modules are installed on the top of the casting mold. A vertical pouring column is fixedly installed on the top of the horizontal pouring module at the bottom of each workpiece mold. Several inserts are installed around the top of the lower sand box. An upper sand box is inserted into the top of the lower sand box. An installation plate is installed in the cavity around the outside of the lower sand box. Vibration striking mechanisms are provided in the cavity around the outside of the lower sand box. Several locking mechanisms are provided in the cavity around the outside of the upper sand box. The vibration striking mechanism includes a limiting rod inside a limiting sliding mounting plate, with a striking plate installed at one end of the limiting rod and an abutting platform installed at the other end. It also includes a connecting plate installed in the cavity around the outside of the lower sand box. A moving rod is laterally limited and slidable on the surface of the connecting plate. A drive disk is installed on the surface of the connecting plate via a micro motor. A micro push rod is installed on the surface of the drive disk. An abutting block is installed at the extended end of the micro push rod. A pull rod is installed at the end of the moving rod.

[0006] Preferably, one set of workpiece molds has grooves on its symmetrical surfaces, and another set of workpiece molds has insert plates fixed on its symmetrical surfaces. Insert rods are vertically inserted into the grooves, and the insert plates have insertion holes corresponding to the insert rods.

[0007] Preferably, there are two direct casting mold columns, which are designed as cones from top to bottom, with an upper diameter of 120 mm and a lower diameter of 90 mm; there are two horizontal casting modules, arranged on both sides, with a single width of 112 mm and a height of 80 mm; a short insert rod is connected between each horizontal casting module and its corresponding workpiece mold, and the short rod is designed with a single width of 60 mm and a height of 12 mm; there are 12 riser modules at the top of the casting mold, and each riser module has a lower diameter of 90 mm, an upper diameter of 292 mm, and a total height of 450 mm.

[0008] Preferably, the striking plate abuts against the inner wall of the outer cavity of the lower sand box near the inner side of the lower sand box, a spring is installed on the back end of the striking plate, the other end of the spring is connected to the mounting plate, and a protrusion is installed on the side of the contact platform near the striking plate, the surface of the protrusion is designed to be inclined.

[0009] Preferably, the middle part of the moving rod has an inverted "U" shape design. When the drive disc rotates, the abutment block abuts against the middle part of the moving rod. A spring is sleeved on the surface of the moving rod near the abutment platform. One end of the spring is connected to the connecting plate, and the other end is connected to the pull rod. The pull rod has a "U" shape design. The vertical rod of the pull rod near the abutment platform abuts against the inclined surface of the protrusion on the surface of the abutment platform.

[0010] Preferably, a plurality of locking mechanisms correspond one-to-one with a plurality of insert blocks. The locking mechanism includes two sliding plates that are symmetrically limited and slide within the cavity of the upper sand box. A sliding rod is provided inside the sliding plate for limiting sliding. A locking plate is installed at the end of the sliding rod near the insert block. A connecting rod is installed on the side of the sliding plate near the insert block. The mechanism also includes a micro motor installed inside the cavity of the upper sand box. A turntable is installed at the output end of the micro motor.

[0011] Preferably, the insert block is provided with limiting teeth on both sides, and the locking plate is provided with limiting teeth on the side near the insert block, and the limiting teeth on the side of the locking plate correspond to the limiting teeth on the side of the insert block.

[0012] Preferably, a spring is fitted on the surface of the slide rod, one end of the spring is connected to the slide plate, and the other end of the spring is connected to the locking plate; two sets of arc-shaped inclined grooves are opened inside the turntable, and the two sets of arc-shaped inclined grooves are arranged opposite to each other inside the turntable, and the top protrusion of the connecting rod slides within the arc-shaped groove inside the turntable.

[0013] Preferably, the method includes the following steps: S1: Insert the mold plate into the corresponding groove, insert the rod into the insertion hole to complete the casting mold assembly; fill the sand box with sand and compact it, the micro motor drives the drive plate to rotate, and the spring reset drives the tapping plate to knock the sand box to assist in compaction. S2: As the amount of sand increases, the micro push rod drives the contact block to extend, amplifying the travel of the moving rod and the pull rod, further increasing the striking force of the patting plate and improving the compaction effect of the sand box filling. S3: After the lower sand box is filled with sand and leveled, the mold is placed in it and connected to the upper sand box. The insert block is inserted and locked. The micro motor drives the turntable, which drives the slide plate to slide, thus strengthening the locking and fastening effect of the upper and lower sand boxes.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention, through the precise matching design of the horizontal gating module, riser module, and direct gating mold column, constructs a scientifically sound and rationally designed dedicated pouring channel. This enables the casting to solidify sequentially from bottom to top, efficiently compensating for the thick cross-sections and hot spots of large butterfly valves. It effectively eliminates internal defects such as shrinkage cavities and porosity, ensuring a dense and uniform casting structure, significantly improving the overall molding quality of large butterfly valves, and meeting their requirements for high-pressure sealing and long-term stable operation. Furthermore, this pouring mold adopts a split assembly structure design, which offers significant advantages over integral molds, substantially reducing mold transportation costs.

[0015] This invention utilizes a micro-motor to drive a rotating drive disc, which, in conjunction with a spring-driven striking plate, reciprocates to strike the sidewalls of the sand box. This automatically assists in compacting the internal sand, compensating for the uneven compaction and loose sand at the edges caused by manual tamping. It reduces the labor intensity of manual compaction, shortens the sand filling and compaction time, and improves overall sand production efficiency. As the amount of sand inside the sand box increases, the micro-push rod can adaptively extend the extension length of the contact block, amplify the travel of the moving rod, and deepen the spring compression, simultaneously increasing the impact force of the striking plate. This provides stronger vibration compaction for thick and deep sand layers, effectively eliminating internal voids in the sand, improving the overall density of the sand mold, preventing sand mold collapse and leakage during casting, and ensuring a stable foundation for the casting. Furthermore, it can adapt to different sand filling heights, matching the corresponding vibration intensity throughout the process, resulting in higher consistency in sand production and molding.

[0016] 3. In this invention, when the upper and lower sand boxes are closed, a self-locking structure is formed by the insert block, limiting teeth, and sliding spring, which quickly completes the initial positioning and locking. When the equipment's vibration compaction mechanism increases the impact force and the sand inside the sand box expands and generates lateral extrusion force, the micro motor drives the turntable to tighten the sliding plates on both sides towards the insert block, and the compression of the sliding spring further strengthens the meshing locking force of the teeth, simultaneously improving the locking strength of the upper and lower sand boxes. This can counteract the tendency of sand box separation caused by sand expansion and high-frequency impact, prevent the gaps between the boxes from opening, and prevent sand leakage, ensuring the overall sealing of the sand box. The locking mechanism can adapt to high-intensity vibration compaction conditions, avoid misalignment and displacement of the upper and lower sand boxes, stabilize the dimensional accuracy of the sand mold cavity, reduce casting flash and dimensional deviation defects, and simultaneously take into account automatic vibration compaction and synchronous locking linkage adjustment, improving the mold casting and forming qualification rate. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the main structure of the present invention; Figure 2 This is a schematic diagram showing the disassembled structure of the casting mold of the present invention; Figure 3 This is a schematic diagram of the splicing structure of the lower sand box and the upper sand box of the present invention; Figure 4 This is a schematic diagram of the disassembled structure of the lower sand box and the upper sand box of the present invention; Figure 5 For the present invention Figure 4 Enlarged structural diagram at point A; Figure 6 This is a schematic diagram of the disassembled structure of the vibration striking mechanism of the present invention; Figure 7 This is a schematic diagram of the disassembled structure of the locking mechanism of the present invention.

[0018] In the diagram: 1. Casting mold; 2. Lower sand box; 3. Upper sand box; 4. Horizontal pouring module; 5. Riser module; 6. Direct pouring mold column; 7. Insert rod; 8. Insert block; 9. Mounting plate; 101. Impact plate; 102. Contact platform; 103. Connecting plate; 104. Moving rod; 105. Drive disc; 106. Miniature push rod; 107. Contact block; 108. Pull rod; 111. Slide plate; 113. Slide rod; 114. Connecting rod; 115. Turntable; 116. Locking plate. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0020] Please see Figures 1-7 This invention provides a technical solution: a bottom-pouring casting equipment and method for a large butterfly valve body made of ductile iron, including a casting mold 1 and a lower sand box 2. The casting mold 1 is composed of two symmetrically inserted workpiece molds. One set of workpiece molds has grooves on its symmetrical surface, and the other set of workpiece molds has insert plates fixed on its symmetrical surface. Insert rods 7 are vertically inserted in the grooves. Insert holes corresponding to the insert rods 7 are opened inside the insert plates. The bottom of the two workpiece molds are connected to horizontal pouring modules 4 by several short rods. Several riser modules 5 are installed on the top of the casting mold 1. Vertical pouring column 6 is fixedly installed on the top of the horizontal pouring modules 4 at the bottom of the two workpiece molds. Several insert blocks 8 are installed around the top of the lower sand box 2. The upper sand box 3 is inserted into the top of the lower sand box 2. An installation plate 9 is installed in the cavity around the outside of the lower sand box 2. Vibration striking mechanisms are set in the cavity around the outside of the lower sand box 2. Several locking mechanisms are set in the cavity around the outside of the upper sand box 3. There are two direct casting mold columns 6, and the whole is designed as a cone barrel from top to bottom, with an upper diameter of 120 mm and a lower diameter of 90 mm. There are two horizontal casting modules 4, which are arranged on both sides, with a single width of 112 mm and a height of 80 mm. There are 8 short rods connected between each horizontal casting module 4 and its corresponding workpiece mold. The short rods are designed with a single width of 60 mm and a height of 12 mm. There are 12 riser modules 5 at the top of the casting mold 1. The specifications of each riser module 5 are a bottom diameter of 90 mm, an upper diameter of 292 mm, and a total height of 450 mm. Through the precise matching and arrangement of the horizontal gating module 4, short rods, and direct gating column 6, an integrated pouring channel of direct gating, horizontal gating, and ingate is precisely constructed inside the sand box, and the cross-sectional ratio of the pouring system is limited to direct gating: horizontal gating: ingate = 1:1.41:0.9. This scientifically proportioned structure can effectively stabilize the flow rate and flow state of the molten metal filling the mold, avoid problems such as turbulence, air entrapment, and splashing, and achieve a smooth and sequential solidification of the casting from bottom to top. It can provide continuous and efficient feeding for the thick cross-section and hot spot enrichment areas of large butterfly valves, significantly eliminate typical casting defects such as shrinkage cavities and porosity inside the casting, ensure that the matrix structure of the casting is dense and uniform, greatly improve the overall forming accuracy and structural strength of large butterfly valves, and effectively meet the needs of high-pressure sealing conditions and long-term stable operation of products.

[0021] As one embodiment of the present invention, the vibration striking mechanism includes a limiting rod inside the limiting sliding mounting plate 9, a striking plate 101 installed at one end of the limiting rod, the striking plate 101 abutting against the inner wall of the outer cavity of the lower sand box 2 near the inner wall of the lower sand box 2, a spring installed at the back end of the striking plate 101, the other end of the spring being connected to the mounting plate 9, a protrusion installed on the side of the contact platform 102 near the striking plate 101, the surface of the protrusion being inclined, and the contact platform 102 installed at the other end, and also includes a connecting plate 103 installed in the outer periphery cavity of the lower sand box 2; A sliding rod 104 is laterally limited and slidable on the surface of the connecting plate 103. The middle part of the sliding rod 104 has an inverted "U" shape design. When the drive disk 105 rotates, the abutment block 107 abuts against the middle part of the sliding rod 104. A spring is sleeved on the surface of the sliding rod 104 near the abutment table 102. One end of the spring is connected to the connecting plate 103, and the other end is connected to the pull rod 108. The pull rod 108 has a "U" shape design. The vertical rod of the pull rod 108 near the abutment table 102 abuts against the inclined surface of the protrusion on the surface of the abutment table 102. The drive disk 105 is mounted on the surface of the connecting plate 103 through a micro motor. A micro push rod 106 is mounted on the surface of the drive disk 105. The abutment block 107 is mounted on the extended end of the micro push rod 106. The pull rod 108 is mounted on the end of the sliding rod 104. During operation, the insert plates on both sides of the mold are inserted into the corresponding grooves, and the insert rod 7 is inserted to complete the assembly of the casting mold. Then, sand is filled into the sand box below. The micro motor drives the drive plate 105 to rotate continuously. The contact block 107 intermittently pushes the moving rod 104 to compress the end spring, pulling the pull rod 108 outward. The vertical rod of the pull rod 108 presses against the inclined surface of the contact platform 102, pushes open the limit rod and compresses its outer spring. After the contact block 107 is separated from the moving rod 104, the two springs rebound synchronously, driving the striking plate 101 to quickly hit the inner wall of the sand box, automatically assisting in the compaction of the molding sand, making up for the problem of uneven strength and loose sand in corners caused by manual compaction, reducing manual labor consumption and speeding up the sand filling process. As the sand in the sand box continues to accumulate and thicken, the micro push rod 106 pushes the contact block 107 to extend its reach, extending the travel of the moving rod 104 and the pull rod 108, further compressing the stored energy of the spring, amplifying the impact force of the striking plate 101, fully compacting the thick layer of sand, eliminating voids inside the sand body, improving the overall density of the sand mold, and preventing the sand mold from collapsing and leaking during pouring; this mechanism can adaptively adjust the striking intensity according to the sand filling height, and different sand filling amounts can match the corresponding vibration effect, ensuring that the sand mold is formed uniformly and stably.

[0022] In one embodiment of the present invention, a plurality of locking mechanisms correspond one-to-one with a plurality of insert blocks 8. Each locking mechanism includes two sliding plates 111 symmetrically limited and slidable within the cavity of the upper sand box 3. A sliding rod 113 is slidably limited inside each sliding plate 111. A locking plate 116 is installed at one end of the sliding rod 113 near the insert block 8. A connecting rod 114 is installed on the side of the sliding plate 111 near the insert block 8. The system also includes a micro motor installed within the cavity of the upper sand box 3. A turntable 115 is installed at the output end of the micro motor. The insert blocks 8 are located on both sides... Limiting teeth are installed, and the locking plate 116 has limiting teeth on the side near the insert block 8. The limiting teeth on the side of the locking plate 116 correspond to the limiting teeth on the side of the insert block 8. A spring is sleeved on the surface of the slide rod 113. One end of the spring is connected to the slide plate 111, and the other end of the spring is connected to the locking plate 116. Two sets of arc-shaped inclined grooves are opened inside the turntable 115. The two sets of arc-shaped inclined grooves are arranged opposite to each other inside the turntable 115. The top protrusion of the connecting rod 114 is limited and slides within the arc-shaped groove inside the turntable 115. After filling the sand to the appropriate height and leveling it, place the assembled casting mold in the lower sand box 2, and then lower the upper sand box 3 to complete the docking. Insert the insert block 8 into the insertion hole of the upper sand box 3. During the descent, the limiting teeth on both sides of the insert block 8 squeeze the slide rod 113 to compress the spring. Relying on the spring rebound, the tooth surfaces bite each other, realizing the initial self-locking and fitting of the upper and lower sand boxes 2. The operation is simple and the box positioning is completed quickly. As the amount of molding sand filling the sand box increases, the impact vibration strength inside the sand box also increases. The expansion of the sand and continuous impact easily generate a force that can open up the sand box. At this time, the micro motor drives the turntable 115 to rotate, and with the help of the arc groove, pushes the two side slide plates 111 towards the insert block 8, further squeezing the spring of the slide rod 113 and strengthening the locking force of the limit teeth. This linkage locking structure can synchronously match the load changes of the vibration compaction condition, effectively offsetting the sand box separation stress caused by sand expansion and high-frequency impact, eliminating the problems of gaps in the box and sand leakage, ensuring the overall sealing of the sand box, preventing misalignment of the upper and lower sand boxes 2, stabilizing the dimensional accuracy of the cavity, reducing casting flash and dimensional defects, and realizing adaptive linkage between vibration compaction and locking force, significantly improving the casting forming qualification rate.

[0023] As one embodiment of the present invention, the method includes the following steps: S1: Insert the mold plate into the corresponding groove, insert the rod 7 into the insertion hole to complete the assembly of the casting mold 1; fill the sand box 2 with sand and compact it, the micro motor drives the drive plate 105 to rotate, and the spring reset drives the tapping plate 101 to tap the sand box to assist in compaction. S2: As the amount of sand increases, the micro push rod 106 drives the contact block 107 to extend, amplifying the travel of the moving rod 104 and the pull rod 108, further increasing the striking force of the striking plate 101, and improving the compaction effect of the sand box filling. S3: After the lower sand box 2 is filled with sand and leveled, it is placed into the mold and connected to the upper sand box 3. The insert block 8 is inserted and locked. The micro motor drives the turntable 115, which drives the slide plate 111 to slide, thereby strengthening the locking and fastening effect of the upper and lower sand boxes.

[0024] Working principle: First, insert plates are inserted into the symmetrical plane of one set of workpiece molds, and grooves are inserted into the symmetrical plane of another set of workpiece molds. Then, insert rod 7 is inserted into the groove and the insertion hole inside the insert plate to assemble the casting mold 1. Then, sand is put into the lower sand box 2 and manually compacted. At the same time, the drive disk 105 is driven to rotate by a micro motor. When the drive disk 105 rotates, the abutment block 107 abuts against the moving rod 104, causing it to drive the pull rod 108 to move away from the abutment platform 102. At this time, the spring at the end of the moving rod 104 is in a compressed state. When the abutment block 107 disengages from the moving rod 104, the compressed spring automatically resets, causing the pull rod 108 to instantly return to its original position. While the pull rod 108 is moving, the inner vertical rod abuts against the inclined surface of the protrusion at the back end of the abutment platform 102, causing it to drive the limiting rod to move away from the side wall of the inner cavity of the lower sand box 2, so that the striking plate 101 leaves the inner wall of the outer cavity of the lower sand box 2. At this time, the spring on the surface of the limiting rod is in a compressed state. In the retracted state, when the pull rod 108 returns to its original position, the rebound force of the compression spring on the surface of the limit rod drives the striking plate 101 to strike the inside of the lower sand box 2, assisting the workers in compacting the inside of the lower sand box 2 and the upper sand box 3. As the amount of sand inside gradually increases, the micro push rod 106 gradually drives the contact block 107 to extend. At this time, when the drive disc 105 rotates, the contact position of the moving rod 104 against the contact block 107 increases, making the moving rod 104 move further on the surface of the connecting plate 103, and the compression state of the spring at the end of the moving rod 104 further expands, causing the pull rod 108 to move a distance that also increases. As the moving distance of the pull rod 108 increases, the squeezing force of the internal vertical rod against the inclined surface of the protrusion at the back end of the contact platform 102 increases simultaneously, making the limit rod move a greater distance away from the side wall of the cavity inside the lower sand box 2. At this time, when the striking plate 101 is released, the striking force on the inside of the lower sand box 2 increases simultaneously, increasing the auxiliary filling effect inside the sand box. After filling the lower sand box 2 with sand to the appropriate position and leveling the sand, the assembled casting mold 1 is placed inside the lower sand box 2. The upper sand box 3 is then inserted into the top of the lower sand box 2. At this time, the insert block 8 is inserted into the bottom insertion hole of the upper sand box 3. When the upper sand box 3 descends, the limiting teeth on both sides of the insert block 8 press against the limiting teeth inside the micro push rod 106. At this time, the limiting teeth inside the locking plate 116 are compressed, causing the slide rod 113 to move towards the inside of the sliding plate 111. The rebound force generated by the spring on the surface of the slide rod 113 causes the limiting teeth on both sides of the insert block 8 to contact the limiting teeth inside the micro push rod 106. The positioning teeth remain locked until the top of the lower sand box 2 and the top of the upper sand box 3 are in close contact. As the amount of sand inside the lower sand box 2 and the upper sand box 3 gradually increases, the striking force inside the lower sand box 2 increases synchronously. This causes the turntable 115 to rotate via a micro motor. The inclined arc groove inside the turntable 115 causes the top protrusion of the connecting rod 114 to slide, which in turn causes the two sets of symmetrically sliding slide plates 111 to slide towards the insert block 8. This increases the reverse resistance of the slide plate 111 against the spring on the surface of the slide rod 113, thereby increasing the locking effect between the lower sand box 2 and the upper sand box 3.

[0025] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A bottom-pouring casting device for a large butterfly valve body made of ductile iron, comprising a casting mold (1) and a lower sand box (2), characterized in that: The casting mold (1) is composed of two symmetrically inserted workpiece molds. The bottom of the two workpiece molds is connected to a horizontal pouring module (4) by several short rods. The top of the casting mold (1) is equipped with several riser modules (5). The top of the horizontal pouring module (4) at the bottom of the two workpiece molds is fixedly installed with a straight pouring mold column (6). Several inserts (8) are installed around the top of the lower sand box (2). An upper sand box (3) is inserted into the top of the lower sand box (2). An installation plate (9) is installed in the cavity around the outside of the lower sand box (2). A vibration knocking mechanism is provided in the cavity around the outside of the lower sand box (2). Several locking mechanisms are provided in the cavity around the outside of the upper sand box (3). The vibration striking mechanism includes a limiting rod inside the limiting sliding mounting plate (9), with a striking plate (101) installed at one end of the limiting rod and a contact platform (102) installed at the other end. It also includes a connecting plate (103) installed in the cavity around the outside of the lower sand box (2). A moving rod (104) is laterally limited and slidable on the surface of the connecting plate (103). A drive disk (105) is installed on the surface of the connecting plate (103) via a micro motor. A micro push rod (106) is installed on the surface of the drive disk (105). A contact block (107) is installed at the extended end of the micro push rod (106). A pull rod (108) is installed at the end of the moving rod (104).

2. The bottom-pouring casting equipment for a large butterfly valve body made of ductile iron according to claim 1, characterized in that: A set of workpiece molds has grooves on its symmetrical surface, and another set of workpiece molds has insert plates fixed on its symmetrical surface. Insert rods (7) are vertically inserted into the grooves, and the insert plates have insertion holes corresponding to the insert rods (7).

3. The bottom-pouring casting equipment for a large butterfly valve body made of ductile iron according to claim 2, characterized in that: The number of direct casting mold columns (6) is two, and the whole is designed as a cone barrel from top to bottom, with an upper diameter of 120 mm and a lower diameter of 90 mm; the number of horizontal casting modules (4) is two, arranged on both sides, with a single width of 112 mm and a height of 80 mm; between each horizontal casting module (4) and its corresponding workpiece mold, there are 8 short rods connected by insert blocks, and the short rods are designed with a single width of 60 mm and a height of 12 mm; the number of riser modules (5) at the top of the casting mold (1) is 12, and the specifications of a single riser module (5) are a bottom diameter of 90 mm, an upper diameter of 292 mm, and a total height of 450 mm.

4. The bottom-pouring casting equipment for a large butterfly valve body made of ductile iron according to claim 3, characterized in that: The striking plate (101) abuts against the inner wall of the outer cavity of the lower sand box (2) near the inner side of the lower sand box (2). A spring is installed on the back end of the striking plate (101), and the other end of the spring is connected to the mounting plate (9). A protrusion is installed on the side of the contact platform (102) near the striking plate (101), and the surface of the protrusion is designed to be inclined.

5. The bottom-pouring casting equipment for a large butterfly valve body made of ductile iron according to claim 4, characterized in that: The middle part of the moving rod (104) is an inverted "U" shape. When the drive disk (105) rotates, the abutment block (107) abuts against the middle part of the moving rod (104). A spring is sleeved on the surface of the moving rod (104) near the abutment platform (102). One end of the spring is connected to the connecting plate (103), and the other end is connected to the pull rod (108). The pull rod (108) is a "U" shape. The vertical rod of the pull rod (108) near the abutment platform (102) abuts against the inclined surface of the protrusion on the surface of the abutment platform (102).

6. The bottom-pouring casting equipment for a large butterfly valve body made of ductile iron according to claim 5, characterized in that: Several locking mechanisms correspond one-to-one with several insert blocks (8). The locking mechanism includes two sliding plates (111) that are symmetrically limited and slidable in the cavity of the upper sand box (3). The sliding plates (111) are limited and slidable by sliding rods (113). A locking plate (116) is installed on one end of the sliding rods (113) near the insert block (8). A connecting rod (114) is installed on the side of the sliding plates (111) near the insert block (8). It also includes a micro motor installed in the cavity of the upper sand box (3). A turntable (115) is installed on the output end of the micro motor.

7. A bottom-pouring casting equipment for a large butterfly valve body made of ductile iron according to claim 6, characterized in that: Limiting teeth are installed on both sides of the insert (8), and the locking plate (116) has limiting teeth on the side near the insert (8). The limiting teeth on the side of the locking plate (116) correspond to the limiting teeth on the side of the insert (8).

8. The bottom-pouring casting equipment for a large butterfly valve body made of ductile iron according to claim 7, characterized in that: The slide bar (113) is fitted with a spring, one end of which is connected to the slide plate (111), and the other end of which is connected to the locking plate (116). The turntable (115) has two sets of arc-shaped inclined grooves inside, which are arranged opposite to each other inside the turntable (115). The top of the connecting rod (114) protrudes and slides within the arc-shaped groove inside the turntable (115).

9. A method of using a bottom-pouring casting equipment for a large butterfly valve body made of ductile iron, applicable to the bottom-pouring casting equipment for a large butterfly valve body made of ductile iron as described in any one of claims 1-8, characterized in that: The method includes the following steps: S1: Insert the mold insert plate into the corresponding groove, insert the rod (7) into the insertion hole to complete the assembly of the casting mold (1); fill the sand box (2) with sand and compact it, drive the drive plate (105) to rotate with the spring reset to drive the striking plate (101) to strike the sand box to assist in compaction; S2: As the amount of sand increases, the micro push rod (106) drives the contact block (107) to extend, amplifying the travel of the moving rod (104) and the pull rod (108), further increasing the striking force of the striking plate (101) and improving the compaction effect of the sand box filling. S3: After filling the lower sand box (2) with sand and leveling it, place it into the mold and connect it to the upper sand box (3). Insert the plug (8) and lock it in place. The micro motor drives the turntable (115) to drive the slide plate (111) to slide, thereby strengthening the locking and fastening effect of the upper and lower sand boxes.

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