Screening device of molding sand for butterfly valve casting

Abstract

The invention relates to the technical field of foundry sand treatment devices, in particular to a screening device for butterfly valve casting molding sand, which comprises a buffer tank and a base, the upper end of the base is fixedly connected with a filtering tank, the outer side of the filtering tank is provided with a first motor, and the inner side of the filtering tank is provided with a filtering mechanism for screening the molding sand. A conveying belt is installed at the upper end of the base, a discharging mechanism used for evenly discharging molding sand is installed at the upper end of the conveying belt, aiming at radioactive impurities of the nuclear power butterfly valve to the molding sand, through combination of visual recognition and magnetic separation, the content of metal impurities is reduced, and the casting standard of nuclear first-grade components is met; sintered sand blocks larger than 1.5 mm can be accurately removed, it is avoided that the sintered sand blocks block a follow-up screen or the strength of a sand mold is uneven, the 0.8 mm aperture of the woven mesh is matched with vibration of the arc-edge sleeve to prevent blocking, coarse sand grading of silica sand is achieved, and the problem that in traditional screening, fine powder agglomerates, and air permeability is insufficient is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of foundry sand treatment, and specifically to a screening device for molding sand used in butterfly valve casting. Background Art

[0002] As a core component for fluid control, the casting quality of butterfly valves directly affects the safe operation of key fields such as energy and chemical industries. In the fields of nuclear power, high temperature and high pressure, and environmental protection and regeneration, higher requirements are put forward for the screening of molding sand.

[0003] For nuclear grade 1 butterfly valves, the content of metallic impurities in the molding sand is required to be ≤0.05%. Traditional manual visual inspection cannot meet the accuracy requirements, and sintered sand blocks >1.5 mm are likely to block the screen mesh, resulting in uneven local strength of the sand mold and possibly causing serious accidents such as valve body leakage. Traditional vibrating screens can only screen out coarse blocks with a pore size >2 mm, and the leakage rate of sintered sand blocks with a size of 1.5 - 2 mm reaches 15%. Moreover, they cannot identify the morphological differences between radioactive metallic impurities and special aggregates. The removal of impurities in nuclear power grade molding sand relies on costly off-line detection, with low efficiency. High temperature butterfly valves resistant to over 1000 °C need to use special aggregates such as zircon sand and chromite sand, and the surface charge density of their particles is as high as 20 nC / g. Due to electrostatic agglomeration, the screening rate of traditional screen meshes drops by more than 30%. In addition, impurities such as titanium dioxide are similar in appearance to the aggregates, making it difficult for manual workers to distinguish them, which is likely to cause sand sticking and hot cracks in the castings. Therefore, we propose a screening device for molding sand used in butterfly valve casting. Summary of the Invention

[0004] In order to make up for the deficiencies of the prior art and solve at least one of the technical problems proposed in the background art, the present invention proposes a screening device for molding sand used in butterfly valve casting.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a screening device for molding sand used in butterfly valve casting, including a base. The upper end of the base is fixedly connected with a filtering tank. A first motor is installed on the outer side of the filtering tank. A filtering mechanism for screening molding sand is arranged inside the filtering tank. A conveyor belt is installed on the upper end of the base, and a feeding mechanism for evenly discharging molding sand is installed on the upper end of the conveyor belt.

[0006] Preferably, the filtering mechanism includes a block removing component for removing sintered sand blocks, and the filtering mechanism further includes a classification component for realizing coarse sand classification.

[0007] Preferably, the block removal component includes a second motor installed at the upper end of the filter tank. The output shaft of the second motor is fixedly connected with a first auger rod. A feeding sleeve is rotatably connected to the outside of the first auger rod. The lower end of the feeding sleeve is fixedly connected with a punching cone through a connecting rod. The punching cone is rotatably connected to the inside of the filter tank. The filter holes of the punching cone are 1.5 mm round holes, and the round holes are chamfered. The inner wall of the punching cone is provided with inclined surface diversion grooves.

[0008] Preferably, four discharge pipes are fixedly connected to the outside of the feeding sleeve. The inner wall of the discharge pipe is provided with a Teflon coating. The outside of the discharge pipe penetrates through the punching cone, and the other end of the discharge pipe is fixedly connected with a collection box. The inner wall of the collection box is fixedly connected with the punching cone.

[0009] Preferably, a first spur gear is fixedly connected to the outside of the output shaft of the second motor. A first chain is meshed with the outside of the first spur gear. A second spur gear is meshed with the inside of the first chain. The lower end of the second spur gear is fixedly connected with a third spur gear through a rotating shaft. An internal gear ring is meshed with the outside of the third spur gear. The lower end of the internal gear ring is fixedly connected with the punching cone.

[0010] Preferably, the classification component includes a connecting rod fixedly connected with the first auger rod. The lower end of the connecting rod is fixedly connected with a first bevel gear. Two symmetrically arranged second bevel gears are meshed with the outside of the first bevel gear. Air flow pipes are fixedly connected to the opposite ends of the two second bevel gears. The outside of the air flow pipes is rotatably connected to the filter tank. The other ends of the air flow pipes are rotatably connected to the input ports of an air pump. A plurality of linear array cameras are installed on the outside of the air flow pipes. Two symmetrically arranged electromagnetic exhaust heads are installed on the outside of the air flow pipes.

[0011] Preferably, an arc-edge sleeve is fixedly connected to the outside of the air flow pipe. A pressing block is rotatably connected to the outside of the arc-edge sleeve. The upper end of one of the two pressing blocks is concave, and the upper end of the other of the two pressing blocks is convex. A woven mesh is fixedly connected to the lower ends of the two pressing blocks together. The woven mesh is rotatably connected to the inside of the filter tank through a rotating shaft.

[0012] Preferably, the woven mesh is designed in a leaf shape. The woven mesh is made of stainless steel. The wire diameter of the stainless steel wire of the woven mesh is 0.4 mm. A second auger rod is rotatably connected to the upper end of the woven mesh. A spherical connection block is fixedly connected to one end of the second auger rod. The spherical connection block is rotatably connected to the inside of the filter tank. The outside of the spherical connection block is fixedly connected to the output shaft of a first motor. A conductive screen is fixedly connected to the inside of the filter tank. An ITO conductive film is plated on the surface of the conductive screen. A collection hopper is fixedly connected to the lower part of the conductive screen inside the filter tank.

[0013] Preferably, the blanking mechanism includes a fourth straight gear fixedly connected to the output shaft of the first motor. A second chain is meshed and connected to the outside of the fourth straight gear. A fifth straight gear is meshed and connected to the inside of the second chain. One end of the fifth straight gear is fixedly connected to a threaded rod. Both ends of the threaded rod are rotationally connected to a mounting bracket through a rotating shaft. The lower end of the mounting bracket is fixedly connected to the conveyor belt. An installation block is threadedly connected to the outside of the threaded rod. The installation block is designed in a convex shape. An electro-ceramic vibrator is installed inside the installation block. The upper end of the installation block is slidably connected to the mounting bracket. A blanking pipe is fixedly connected to the inside of the installation block. One end of the blanking pipe is fixedly connected to a collecting hopper. An adsorption hose is fixedly connected to the front end of the installation block. An adsorption tank is fixedly connected to the outside of the adsorption hose. A polyurethane screen is arranged inside the adsorption tank. The other end of the adsorption hose is fixedly connected to the input port of an air pump. A laser particle size analyzer is installed at the lower end of the installation block.

[0014] Preferably, the other end of the threaded rod is fixedly connected to a third bevel gear. A fourth bevel gear is meshed and connected to the outside of the third bevel gear. A binder tank is rotationally connected to the front end of the fourth bevel gear. The lower end of the binder tank is fixedly connected to the base. A heating and stirring rod is rotationally connected to the inside of the binder tank. The rear end of the heating and stirring rod is fixedly connected to the fourth bevel gear. An electromagnetic valve spray pipe is installed on one side of the binder tank.

[0015] Compared with the prior art, the present invention provides a screening device for the molding sand used in the casting of butterfly valves, and has the following beneficial effects:

[0016] 1. For the radioactive impurities in the molding sand of nuclear power butterfly valves, through visual recognition, the content of metal impurities is reduced to meet the casting standards of nuclear primary components. Through the 1.5 mm chamfered round holes and inclined surface diversion grooves of the punching cone, sintered sand blocks larger than 1.5 mm can be accurately removed to avoid blocking the subsequent screen or causing uneven sand mold strength. The 0.8 mm aperture of the woven mesh is combined with the arc-edge sleeve vibration anti-blocking to achieve the coarse sand classification of silica sand, solve the problem of insufficient air permeability caused by fine powder agglomeration in traditional screening, control the air permeability of the silica sand molding sand, and meet the strict requirements for the surface roughness of the sand mold in the sealing surface area of the butterfly valve body. By forming a shear force through the rotational speed difference between the auger rod and the cone rotating in opposite directions, the slightly caked molding sand is broken, the molding sand is forced to adhere to the cylinder wall, and the fine particles are accelerated to pass through the screen holes, realizing the efficient separation of ultra-large particles, and improving the proportion of effective particles in the subsequent screening.

[0017] 2. With the air flow assistance of the air flow pipe on the surface of the conductive screen mesh, the static electricity generated by the friction of zircon sand particles is eliminated, avoiding the decrease in the screen passing rate caused by agglomeration, greatly increasing the proportion of effective particles in the zircon sand molding sand. The linear array camera combines with the deep learning algorithm to identify impurities with similar appearances such as zircon sand and titanium dioxide in real time, and accurately remove abnormal particles through the electromagnetic exhaust head, solving the industry problem that traditional screening cannot distinguish special aggregates from impurities, ensuring the refractoriness and anti-adhesion properties of the molding sand for high-temperature butterfly valves, and avoiding casting defects such as sand adhesion and cracks caused by impurities entering the sand mold.

[0018] 3. The adsorption hose and the polyurethane screen mesh capture fine powder less than 0.2 mm and broken resin films. Combined with the constant temperature treatment of the binder by the heating stirring rod, the ignition loss of the recycled sand is ≤ 3%, the acid consumption value is ≤ 5 mL, and the recycling rate is improved. The laser particle size analyzer detects the specific surface area in real time, and the linkage solenoid valve spray pipe dynamically adjusts the resin addition amount, solving the problem of unbalanced binder ratio caused by the change of the particle morphology of the recycled sand, and significantly reducing the cracking rate and porosity defect rate of the butterfly valve sand core. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 is a schematic cross-sectional view of the overall structure of the present invention;

[0021] Figure 3 is a schematic cross-sectional view of the overall structure of the filtering mechanism of the present invention;

[0022] Figure 4 is a schematic diagram of the overall structure of the rejection block assembly of the present invention;

[0023] Figure 5 is a schematic cross-sectional view of the overall structure of the rejection block assembly of the present invention;

[0024] Figure 6 is a schematic diagram of a partial structure of the classification assembly of the present invention;

[0025] Figure 7 of the present invention Figure 6 is an enlarged schematic diagram of the structure of part A;

[0026] Figure 8 of the present invention Figure 6 is an enlarged schematic diagram of the structure of part B;

[0027] Figure 9 is a schematic cross-sectional view of the overall structure of the blanking mechanism of the present invention.

[0028] In the figure: 1. Base; 2. Filter tank; 3. First motor; 4. Filter mechanism; 41. Block removing assembly; 411. Second motor; 412. First auger rod; 413. Feeding sleeve; 414. Punching cone; 415. Discharge pipe; 416. Collection box; 417. First spur gear; 418. First chain; 419. Second spur gear; 4110. Third spur gear; 4111. Internal gear ring; 42. Classification assembly; 421. Connecting rod; 422. First bevel gear; 423. Second bevel gear; 424. Air flow pipe; 425. Arc-edge sleeve; 426. Pressing block; 427. Linear array camera; 428. Electromagnetic exhaust head; 429. Woven mesh; 4210. Second auger rod; 4211. Spherical connecting block; 4212. Conductive screen; 4213. Collection hopper; 5. Feeding mechanism; 51. Fourth spur gear; 52. Second chain; 53. Fifth spur gear; 54. Threaded rod; 55. Mounting block; 56. Feeding pipe; 57. Mounting frame; 58. Adsorption hose; 59. Third bevel gear; 510. Fourth bevel gear; 511. Binder tank; 512. Heating and stirring rod; 513. Solenoid valve spray pipe; 6. Conveyor belt. Detailed implementation mode

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention.

[0030] The following electrical components are all electrically connected through a peripheral PLC controller.

[0031] Please refer to Figures 1 - 9 , a screening device for molding sand used in butterfly valve casting, including a base 1, a filter tank 2 is fixedly connected to the upper end of the base 1, a first motor 3 is installed outside the filter tank 2, a filter mechanism 4 for screening molding sand is arranged inside the filter tank 2, a conveyor belt 6 is installed on the upper end of the base 1, and a feeding mechanism 5 for evenly discharging molding sand is installed on the upper end of the conveyor belt 6.

[0032] In this embodiment, the filter mechanism 4 includes a block removing assembly 41 for removing sintered sand blocks, and the filter mechanism 4 further includes a classification assembly 42 for realizing coarse sand grading.

[0033] Specifically, the block removing assembly 41 is responsible for removing sintered sand blocks larger than 1.5 mm to ensure subsequent grading accuracy. The classification assembly 42 realizes coarse sand grading with a particle size of 0.8 mm through air flow assisted screening and vibration anti-blocking, and performs electrostatic agglomeration treatment on qualified particles.

[0034] In this embodiment, the block removing component 41 includes a second motor 411 installed at the upper end of the filter tank 2. The output shaft of the second motor 411 is fixedly connected with a first auger rod 412. A feeding sleeve 413 is rotatably connected to the outside of the first auger rod 412. The lower end of the feeding sleeve 413 is fixedly connected with a punching cone 414 through a connecting rod. The punching cone 414 is rotatably connected to the inside of the filter tank 2. The filtering holes of the punching cone 414 are 1.5-mm round holes, and the round holes are chamfered. The inner wall of the punching cone 414 is provided with inclined plane diversion grooves.

[0035] Specifically, the second motor 411 drives the first auger rod 412 to rotate, and drives the punching cone 414 to rotate oppositely through a gear and chain drive to provide screening power. The first auger rod 412 rotates counterclockwise in the feeding sleeve 413, and spirally lifts the retained sintered sand blocks to the discharge pipeline 415. The feeding sleeve 413 supports the rotation of the first auger rod 412 and fixes the punching cone 414 to form a screening space. The inclined plane diversion grooves on the inner wall of the punching cone 414 guide the molding sand to slide spirally. The 1.5-mm chamfered round holes filter particles with a particle size ≤ 1.5 mm. When rotating, the fine particles pass through the sieve by centrifugal force acceleration.

[0036] In this embodiment, four groups of discharge pipelines 415 are fixedly connected to the outside of the feeding sleeve 413. The inner wall of the discharge pipeline 415 is provided with a Teflon coating. The outside of the discharge pipeline 415 penetrates through the punching cone 414. The other end of the discharge pipeline 415 is fixedly connected with a collection box 416. The inner wall of the collection box 416 is fixedly connected with the punching cone 414.

[0037] Specifically, the Teflon coating on the inner wall of the discharge pipeline 415 reduces the friction coefficient to ensure the smooth transportation of the sintered sand blocks, penetrates through the punching cone 414, and is docked with the lifting path of the first auger rod 412. The collection box 416 is fixed to the punching cone 414 to collect the sintered sand blocks transported by the discharge pipeline 415, realizing the centralized recovery of oversize particles.

[0038] In this embodiment, a first spur gear 417 is fixedly connected to the outside of the output shaft of the second motor 411. A first chain 418 is meshed with the outside of the first spur gear 417. A second spur gear 419 is meshed with the inside of the first chain 418. The lower end of the second spur gear 419 is fixedly connected with a third spur gear 4110 through a rotating shaft. A ring gear 4111 is meshed with the outside of the third spur gear 4110. The lower end of the ring gear 4111 is fixedly connected with the punching cone 414.

[0039] Specifically, the second motor 411 drives the second spur gear 419 through the first spur gear 417 and the first chain 418, thereby driving the internal gear ring 4111 through the third spur gear 4110 to drive the punching cone 414, and realizing the opposite rotation of the punching cone 414 and the first auger rod 412 through the gear-chain drive, and enhancing the centrifugal screening effect by using the speed difference.

[0040] In this embodiment, the classification component 42 includes a connecting rod 421 fixedly connected to the first auger rod 412. The lower end of the connecting rod 421 is fixedly connected with a first bevel gear 422. Two groups of symmetrically arranged second bevel gears 423 are meshed on the outer side of the first bevel gear 422. Air flow pipes 424 are fixedly connected to the far ends of the two groups of second bevel gears 423. The outer sides of the air flow pipes 424 are rotatably connected to the filter tank 2. The other ends of the air flow pipes 424 are rotatably connected to the input ports of the air pumps. Multiple groups of line array cameras 427 are installed on the outer sides of the air flow pipes 424. Two groups of symmetrically arranged electromagnetic exhaust heads 428 are installed on the outer sides of the air flow pipes 424.

[0041] Specifically, the connecting rod 421 drives the second bevel gear 423 through the first bevel gear 422 to transfer the rotational power of the first auger rod 412 to the air flow pipe 424, driving the air flow pipe 424 to rotate. The air flow pipe 424 is connected to an air pump, and outputs an up-and-down bidirectional air flow through the electromagnetic exhaust head 428, blowing the sieve holes of the punching cone 414 upward and aggregating sand downward to strengthen classification. The line array camera 427 scans the falling molding sand in real time to identify coarse sand and impurities with a particle size > 0.8 mm, and provides control data for the electromagnetic exhaust head 428.

[0042] In this embodiment, an arc-edge sleeve 425 is fixedly connected to the outer side of the air flow pipe 424. A pressing block 426 is rotatably connected to the outer side of the arc-edge sleeve 425. The upper end of one of the two groups of pressing blocks 426 is concave, and the upper end of the other group of pressing blocks 426 of the two groups of pressing blocks 426 is convex. A woven mesh 429 is fixedly connected to the lower ends of the two groups of pressing blocks 426 together. The woven mesh 429 is rotatably connected to the inner side of the filter tank 2 through a rotating shaft.

[0043] Specifically, the arc-edge sleeve 425 rotates with the air flow pipe 424, and drives the pressing block 426 to reciprocally squeeze the woven mesh 429 through the eccentric profile. The concave-convex surface design of the pressing block 426 causes the woven mesh 429 to generate a 2-5 mm lateral vibration, breaking the particle agglomeration and preventing the 0.8 mm sieve holes from being blocked. The woven mesh 429 is a stainless steel sieve mesh with a 0.8 mm aperture, and is inclined to install to realize coarse sand classification. When vibrating, it guides particles > 0.8 mm to slide towards the second auger rod 4210.

[0044] In this embodiment, the woven mesh 429 is designed in a leaf shape. The woven mesh 429 is made of stainless steel. The wire diameter of the stainless steel wire of the woven mesh 429 is 0.4 mm. The upper end of the woven mesh 429 is rotatably connected to a second auger rod 4210. One end of the second auger rod 4210 is fixedly connected to a spherical connection block 4211. The spherical connection block 4211 is rotatably connected to the inside of the filter tank 2. The outside of the spherical connection block 4211 is fixedly connected to the output shaft of the first motor 3. A conductive screen 4212 is fixedly connected to the inside of the filter tank 2. The surface of the conductive screen 4212 is coated with an ITO conductive film. A collecting hopper 4213 is fixedly connected below the conductive screen 4212 inside the filter tank 2.

[0045] Specifically, the leaf-shaped woven mesh 429 increases the particle contact area and improves the screening efficiency. The stainless steel material is wear-resistant and corrosion-resistant. The second auger rod 4210 is not horizontally installed, and its inclination angle is 15°. It is driven by the first motor 3 through the spherical connection block 4211 to discharge the coarse sand >0.8 mm from the filter tank 2. The conductive film on the surface of the conductive screen 4212 eliminates the electrostatic agglomeration of zircon sand, ensuring that particles below 0.8 mm pass through the screen. The collecting hopper 4213 receives the qualified molding sand filtered by the conductive screen 4212 and conveys it to the feeding mechanism 5.

[0046] In this embodiment, the feeding mechanism 5 includes a fourth spur gear 51 fixedly connected to the output shaft of the first motor 3. A second chain 52 is meshed with the outside of the fourth spur gear 51. A fifth spur gear 53 is meshed with the inside of the second chain 52. One end of the fifth spur gear 53 is fixedly connected to a threaded rod 54. Both ends of the threaded rod 54 are rotatably connected to a mounting bracket 57 through a rotating shaft. The lower end of the mounting bracket 57 is fixedly connected to a conveyor belt 6. A mounting block 55 is threadedly connected to the outside of the threaded rod 54. The mounting block 55 is designed in a convex shape. An electro-ceramic vibrator is installed inside the mounting block 55. The upper end of the mounting block 55 is slidably connected to the mounting bracket 57. A feeding pipe 56 is fixedly connected to the inside of the mounting block 55. One end of the feeding pipe 56 is fixedly connected to the collecting hopper 4213. An adsorption hose 58 is fixedly connected to the front end of the mounting block 55. An adsorption tank is fixedly connected to the outside of the adsorption hose 58. A polyurethane screen is arranged inside the adsorption tank. The other end of the adsorption hose 58 is fixedly connected to the input port of an air pump. A laser particle size analyzer is installed at the lower end of the mounting block 55.

[0047] Specifically, the first motor 3 drives the fourth spur gear 51, and then drives the fifth spur gear 53 through the second chain 52, thereby driving the threaded rod 54 and driving the mounting block 55 to reciprocate along the conveyor belt 6. The electro-ceramic vibrator built into the mounting block 55 vibrates the feeding pipe 56 to prevent blockage. The adsorption hose 58 at the front end is connected to an air pump to capture dust. The laser particle size analyzer real-time detects the specific surface area of the molding sand, providing data support for the addition of the binder. The feeding pipe 56 discharges the molding sand evenly as it moves with the mounting block 55. The conveyor belt 6 extends in an S-shaped path to increase the detection distance.

[0048] In this embodiment, the other end of the threaded rod 54 is fixedly connected with a third bevel gear 59. The outer side of the third bevel gear 59 is meshed and connected with a fourth bevel gear 510. The front end of the fourth bevel gear 510 is rotatably connected with an adhesive tank 511. The lower end of the adhesive tank 511 is fixedly connected with the base 1. The inner side of the adhesive tank 511 is rotatably connected with a heating and stirring rod 512. The rear end of the heating and stirring rod 512 is fixedly connected with the fourth bevel gear 510. One side of the adhesive tank 511 is provided with an electromagnetic valve spray pipe 513.

[0049] Specifically, the threaded rod 54 drives the fourth bevel gear 510 through the third bevel gear 59, thereby driving the heating and stirring rod 512 to constantly stir the resin in the adhesive tank 511. The electromagnetic valve spray pipe 513 automatically adjusts the spraying amount of the adhesive according to the detection data of the laser particle size analyzer to achieve dynamic balance of the ratio.

[0050] Working principle: During use, the molding sand is put into the filter tank 2 and first evenly laid on the punching conical cylinder 414. The inclined surface diversion grooves on the inner wall of the punching conical cylinder 414 guide the molding sand to slide spirally towards the center. During the sliding process, the particles with a particle size ≤ 1.5 mm pass through the chamfered round holes in the cylinder wall and quickly fall. The unfiltered sintered sand blocks stay on the surface of the conical cylinder and are concentrated at the lower end of the feeding sleeve 413, avoiding the hidden dangers of screen blockage and uneven sand mold strength from the source. Start the second motor 411, and its output shaft drives the first auger rod 412 to rotate in the feeding sleeve 413. The retained sintered sand blocks are spirally lifted by the auger rod to the discharge pipeline 415. The Teflon coating on the inner wall of the discharge pipeline 415 ensures low-friction transportation. The output shaft of the second motor 411 drives the first spur gear 417 to rotate. The first spur gear 417 drives the second spur gear 419 to rotate through the first chain 418. The second spur gear 419 drives the internal gear ring 4111 to rotate through the third spur gear 4110. The internal gear ring 4111 drives the punching conical cylinder 414 to rotate, so that the punching conical cylinder 414 and the first auger rod 412 rotate in opposite directions. The centrifugal force generated by the rotation of the punching conical cylinder 414 causes the molding sand to closely adhere to the cylinder wall, accelerating the passage of fine particles through the sieve holes. The sintered sand blocks in the discharge pipeline 415 finally fall into the collection box 416 through centrifugal force, realizing the efficient separation of super-large particles;

[0051] When the first auger rod 412 rotates, it drives the connecting rod 421 to rotate. The connecting rod 421 drives the first bevel gear 422 to rotate. The first bevel gear 422 drives the air flow pipe 424 to rotate through the second bevel gear 423. The air flow pipe 424 drives the linear array camera 427 to scan the falling molding sand particles above in real time, identify the coarse sand with a particle size > 0.8 mm and impurities with similar appearances such as zircon sand and titanium dioxide. The detection data is synchronously transmitted to the control system, automatically adjusting the opening degree of the electromagnetic exhaust head 428 to control the size of the air flow. The upward air flow blows the outer surface of the punching cone 414 to remove the particles that may block the sieve holes. The downward air flow gathers the molding sand above the woven mesh 429 towards the middle to strengthen the classification effect. The air flow pipe 424 drives the arc-edge sleeve 425 to rotate. The arc-edge sleeve 425 causes the woven mesh 429 to sway left and right through the protrusions and grooves of the pressing block 426, periodically squeezing the woven mesh 429 to make the woven mesh 429 sway left and right with an amplitude of 2 - 5 mm, solving the problem of insufficient air permeability caused by fine powder agglomeration, meeting the strict requirements for the surface roughness of the sand mold in the butterfly valve sealing surface area, breaking particle agglomeration and preventing sieve hole blockage, and enabling the coarse sand with a particle size > 0.8 mm to slide along the inclined surface of the woven mesh 429 to the second auger rod 4210. The first motor 3 drives the non - horizontally installed second auger rod 4210 to rotate through the spherical connection block 4211, discharging the coarse sand from the filter tank 2 for recycling. The particles with a size below 0.8 mm passing through the woven mesh 429 fall onto the conductive sieve mesh 4212, and through the internal air flow, the static electricity of the zircon sand particles is eliminated to avoid agglomeration. Finally, the qualified particles fall into the collection hopper 4213 to ensure the refractoriness and anti - burn - on performance of the molding sand for high - temperature butterfly valves;

[0052] The output shaft of the first motor 3 drives the fourth spur gear 51 to rotate. The fourth spur gear 51 drives the fifth spur gear 53 to rotate through the second chain 52. The fifth spur gear 53 drives the threaded rod 54 to rotate within the mounting frame 57. The threaded rod 54 drives the mounting block 55 to move through the thread. The mounting block 55 drives the feeding pipe 56 to discharge the molding sand in the collection hopper 4213 onto the conveyor belt 6. When the mounting block 55 moves, it prevents the feeding pipe 56 from being blocked through the electro - ceramic vibrator. The molding sand is conveyed in an S - shaped path at the upper end of the conveyor belt 6. The air pump adsorbs the dust generated during the fall through the adsorption hose 58, and then captures the fine powder < 0.2 mm through the polyurethane sieve mesh. The threaded rod 54 drives the third bevel gear 59 to rotate. The third bevel gear 59 drives the heating and stirring rod 512 to rotate inside the binder tank 511 to keep the resin at a constant temperature and ensure the spraying accuracy. When the mounting block 55 moves, it drives the laser particle size analyzer to move synchronously for on - line detection. According to the specific surface area of the screened sand grains, the control system automatically adjusts the spraying amount of the electromagnetic valve spray pipe 513 and automatically controls the resin addition amount, solving the problem of imbalance in the binder ratio caused by the change in the morphology of the recycled sand particles, and significantly reducing the cracking rate and porosity defect rate of the butterfly valve sand core.

[0053] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A screening device for molding sand used in butterfly valve casting, including a base (1), characterized in that: The upper end of the base (1) is fixedly connected with a filter tank (2). A first motor (3) is installed on the outer side of the filter tank (2). A filtering mechanism (4) for screening molding sand is arranged inside the filter tank (2). A conveyor belt (6) is installed on the upper end of the base (1). A feeding mechanism (5) for uniformly discharging molding sand is installed on the upper end of the conveyor belt (6). The filtering mechanism (4) includes a picking block assembly (41). The filtering mechanism (4) further includes a sorting assembly (42). The picking block assembly (41) includes a second motor (411) installed on the upper end of the filter tank (2). The output shaft of the second motor (411) is fixedly connected with a first auger rod (412). A feeding sleeve (413) is rotatably connected to the outer side of the first auger rod (412). The lower end of the feeding sleeve (413) is fixedly connected with a punching cone (414) through a connecting rod. The punching cone (414) is rotatably connected inside the filter tank (2). The sorting assembly (42) includes a connecting rod (421) fixedly connected with the first auger rod (412). The lower end of the connecting rod (421) is fixedly connected with a first bevel gear (422). Two groups of symmetrically arranged second bevel gears (423) are meshed with the outer side of the first bevel gear (422). Air flow pipes (424) are fixedly connected to the outer ends of the two groups of second bevel gears (423) away from each other.

2. The screening device for the molding sand used in butterfly valve casting according to claim 1, characterized in that: The filtering holes of the punching cone (414) are 1.5 mm round holes. The round holes are chamfered. An inclined surface diversion groove is arranged on the inner wall of the punching cone (414).

3. The screening device for the molding sand used in butterfly valve casting according to claim 1, wherein: Four discharging pipes (415) are fixedly connected to the outer side of the feeding sleeve (413). A Teflon coating is arranged on the inner wall of the discharging pipes (415). The outer sides of the discharging pipes (415) penetrate through the punching cone (414). The other ends of the discharging pipes (415) are fixedly connected with a collecting box (416). The inner wall of the collecting box (416) is fixedly connected with the punching cone (414).

4. The screening device for the molding sand used in butterfly valve casting according to claim 1, wherein: A first spur gear (417) is fixedly connected to the outer side of the output shaft of the second motor (411). A first chain (418) is meshed with the outer side of the first spur gear (417). A second spur gear (419) is meshed with the inner side of the first chain (418). A third spur gear (4110) is fixedly connected to the lower end of the second spur gear (419) through a rotating shaft. An internal gear ring (4111) is meshed with the outer side of the third spur gear (4110). The lower end of the internal gear ring (4111) is fixedly connected with the punching cone (414).

5. The screening device for the molding sand used in butterfly valve casting according to claim 1, wherein: The outer side of the air flow pipe (424) is rotatably connected with the filter tank (2). The other end of the air flow pipe (424) is rotatably connected with the input port of an air pump. A plurality of line array cameras (427) are installed on the outer side of the air flow pipe (424). Two groups of symmetrically arranged electromagnetic exhaust heads (428) are installed on the outer side of the air flow pipe (424).

6. The screening device for the molding sand used in the casting of a butterfly valve according to claim 1, wherein: An arc-edge sleeve (425) is fixedly connected to the outside of the air flow pipe (424). A pressing block (426) is rotatably connected to the outside of the arc-edge sleeve (425). The upper end of one of the two pressing blocks (426) is concave, and the upper end of the other pressing block (426) of the two pressing blocks (426) is convex. A woven mesh (429) is fixedly connected to the lower ends of the two pressing blocks (426). The woven mesh (429) is rotatably connected to the inside of the filter tank (2) through a rotating shaft.

7. The screening device for the molding sand used in butterfly valve casting according to claim 6, wherein: The woven mesh (429) is designed in a blade shape. The woven mesh (429) is made of stainless steel. The wire diameter of the stainless steel wire of the woven mesh (429) is 0.4 mm. A second auger rod (4210) is rotatably connected to the upper end of the woven mesh (429). One end of the second auger rod (4210) is fixedly connected to a spherical connection block (4211). The spherical connection block (4211) is rotatably connected to the inside of the filter tank (2). The outside of the spherical connection block (4211) is fixedly connected to the output shaft of the first motor (3). A conductive screen (4212) is fixedly connected to the inside of the filter tank (2). The surface of the conductive screen (4212) is coated with an ITO conductive film. A collecting hopper (4213) is fixedly connected to the lower part of the conductive screen (4212) inside the filter tank (2).

8. The screening device for the molding sand used in butterfly valve casting according to claim 1, wherein: The blanking mechanism (5) includes a fourth spur gear (51) fixedly connected to the output shaft of the first motor (3). A second chain (52) is meshed with the outside of the fourth spur gear (51). A fifth spur gear (53) is meshed with the inside of the second chain (52). One end of the fifth spur gear (53) is fixedly connected to a threaded rod (54). Both ends of the threaded rod (54) are rotatably connected to a mounting frame (57) through a rotating shaft. The lower end of the mounting frame (57) is fixedly connected to a conveyor belt (6). A mounting block (55) is threadedly connected to the outside of the threaded rod (54). The mounting block (55) is designed in a convex shape. An electro-ceramic vibrator is installed inside the mounting block (55). The upper end of the mounting block (55) is slidably connected to the mounting frame (57). A blanking pipe (56) is fixedly connected to the inside of the mounting block (55). One end of the blanking pipe (56) is fixedly connected to the collecting hopper (4213). An adsorption hose (58) is fixedly connected to the front end of the mounting block (55). An adsorption tank is fixedly connected to the outside of the adsorption hose (58). A polyurethane screen is arranged inside the adsorption tank. The other end of the adsorption hose (58) is fixedly connected to the input port of an air pump. A laser particle size analyzer is installed at the lower end of the mounting block (55).

9. The screening device for the molding sand used in butterfly valve casting according to claim 8, characterized in that: The other end of the threaded rod (54) is fixedly connected to a third bevel gear (59). The outside of the third bevel gear (59) is meshed with a fourth bevel gear (510). The front end of the fourth bevel gear (510) is rotatably connected to an adhesive tank (511). The lower end of the adhesive tank (511) is fixedly connected to the base (1). The inside of the adhesive tank (511) is rotatably connected to a heating and stirring rod (512). The rear end of the heating and stirring rod (512) is fixedly connected to the fourth bevel gear (510). One side of the adhesive tank (511) is provided with a solenoid valve spray pipe (513).

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