Vacuum maintaining transfer system and transfer method for V-method casting sand box

Abstract

The invention discloses a vacuum maintaining and transferring system and method for a V-method casting sand box, the device comprises a casting mold box and a maintaining assembly, the maintaining assembly comprises a mounting pipe and a three-way pipe rotationally sealed with the mounting pipe, a power part and two closing plates moving in a reciprocating mode in the A direction are arranged in the three-way pipe, and the moving directions of the two closing plates are opposite; a conduit assembly. Power is provided for the power piece through rotation of the three-way pipe, so that the two sealing plates move in the opposite directions, one sealing plate enters the position of a pipe opening of the three-way pipe connected with the filling vacuumizing pipe to seal the pipe opening, and the other sealing plate leaves the position of a pipe opening of the pouring vacuumizing pipe to open the pipe opening. Thus, the filling vacuumizing pipe and the pouring vacuumizing pipe are exchanged in position and changed in working state, the interior of the sand box can be kept in a vacuum state, the situation that the shape of a forming cavity is affected by loose molding sand is avoided, and then the production quality of castings is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of V-process casting, and particularly relates to a V-process casting sand box vacuum maintaining and transporting system and a V-process casting sand box vacuum maintaining and transporting method. Background Art

[0002] V-process casting, also known as vacuum sealed molding or negative pressure molding, uses a plastic film to seal the sand box, and the air inside the mold is pumped out by a vacuum pump to form a pressure difference inside and outside the mold, so that the molding sand is compacted to form the required cavity, and the vacuum pumping operation on the sand box is maintained during casting and cooling, which helps to reduce the dissolution of gas and porosity in the casting during casting, improve the density and uniformity of the casting, and promote the uniform cooling of the casting and reduce internal stress during cooling, reduce casting deformation and improve its structural strength.

[0003] When transporting the lower mold of the sand box or the lower mold of the sand box for mold closing operation, the pipeline for vacuum pumping during the compaction operation of the molding sand needs to be replaced with the pipeline for vacuum pumping during casting and cooling operations. During the period of pipeline replacement, the vacuum pumping operation cannot be maintained inside the sand box, resulting in a small part of the molding sand becoming loose and affecting the shape of the formed cavity, thus affecting the quality of the final casting. Summary of the Invention

[0004] In view of the problem that the vacuum pumping operation cannot be maintained inside the sand box during the pipeline replacement process in the prior art, which affects the shape of the formed cavity and leads to a decline in the quality of the casting, the present invention proposes the following technical solutions:

[0005] A V-process casting sand box vacuum maintaining and transporting system, comprising:

[0006] A mold box, the mold box being an upper mold of the sand box or a lower mold of the sand box, and a through exhaust pipe being provided on one side of the mold box;

[0007] A maintaining assembly, the maintaining assembly including a mounting pipe and a three-way pipe rotatably sealed with the mounting pipe, the mounting pipe being fixedly connected to the exhaust pipe, a power member and two closing plates reciprocating in the A direction being provided inside the three-way pipe, and the two closing plates moving in opposite directions;

[0008] A pipeline assembly, the pipeline assembly including a charging vacuum pipe and a casting vacuum pipe, one ends of the charging vacuum pipe and the casting vacuum pipe being respectively connected to two pipe orifices of the three-way pipe, and the other ends of the charging vacuum pipe and the casting vacuum pipe being both connected to an external vacuum pumping device;

[0009] After the mold box is transported, the pouring evacuation tube is inserted into the three-way pipe and the three-way pipe is rotated half a turn. The power component pushes the two closing plates to move in opposite directions. One of the closing plates enters the position of the nozzle of the three-way pipe connected to the filling evacuation tube to block it, and the other closing plate leaves the position of the nozzle of the three-way pipe of the pouring evacuation tube to open it, converting the filling evacuation tube into a pouring evacuation tube to maintain the vacuum inside the mold box.

[0010] As a preference of the above technical solution, the power component includes a fixed gear fixedly connected to the installation pipe. Auxiliary gears are meshed and connected on both sides of the fixed gear. A reciprocating lead screw is fixedly connected to the middle of the auxiliary gear. A moving slider fixedly connected to the corresponding closing plate is threadedly sleeved on the surface of the reciprocating lead screw.

[0011] As a preference of the above technical solution, one side of the moving slider is movably inserted into an installation frame fixedly connected to the inner wall of the three-way pipe. One section of the installation frame is sleeved on the surface of the reciprocating lead screw.

[0012] As a preference of the above technical solution, the maintaining component further includes a limiting component. The limiting component includes an installation block and two limiting blocks. The installation block is fixedly connected to the fixed gear. Limiting grooves corresponding to the limiting blocks are provided on both sides of the installation block. One end of the limiting block is provided with a rotating rod. One end of the rotating rod rotatably penetrates through the three-way pipe and extends to the outside. The rotating rod is threadedly sleeved at the insertion part with the three-way pipe. A knob is fixedly connected to the end of the rotating rod.

[0013] As a preference of the above technical solution, one end of the limiting block is rectangularly arranged, and the rectangular end of the limiting block is movably inserted into the rotating rod. A return spring is fixedly connected between the limiting block and the rotating rod. The other end of the limiting block is in a slope shape. Rotating rods matching the slope ends of the limiting blocks are provided on both sides of the limiting block in the limiting groove.

[0014] As a preference of the above technical solution, the preliminary evacuation tube is used for vacuum extraction and maintenance inside the mold box during the filling of the molding sand inside the mold box and the transportation of the mold box. The pouring evacuation tube is used for maintaining the vacuum inside the mold box during the product casting and cooling processes.

[0015] As a preference of the above technical solution, sealing films are provided at both the bottom and the top of the mold box. Molding sand is filled between the inner mold box and the two sealing films.

[0016] As a preference of the above technical solution, a transportation component is further included. The transportation component includes a lifting base connected to an external lifting device. A plurality of suspension ropes are provided at the bottom of the lifting base. The suspension ropes lift and transport the mold box through the lifting lugs on the surface of the mold box.

[0017] The transportation method for vacuum maintenance of the V-method casting sand box includes the following steps

[0018] S1. Install the pouring vacuum extraction pipe;

[0019] Fix the pouring vacuum extraction pipe at the pouring position to the nozzle of the three-way pipe, and start the external vacuum extraction device connected to the pouring vacuum extraction pipe;

[0020] S2. Adjust the position of the pouring vacuum extraction pipe;

[0021] Rotate the three-way pipe by half a turn, so that the pouring vacuum extraction pipe and the filling vacuum extraction pipe exchange positions, and the power component then pushes the two closing plates to move in opposite directions;

[0022] S3. Adjust the air extraction position of the nozzle of the three-way pipe;

[0023] One of the closing plates enters the position of the nozzle of the three-way pipe connected to the filling vacuum extraction pipe to block it, and the other closing plate leaves the position of the nozzle of the three-way pipe connected to the pouring vacuum extraction pipe to open it, and start to continuously perform vacuum extraction operation through the nozzle of the three-way pipe connected to the pouring vacuum extraction pipe;

[0024] S4. Remove the filling vacuum extraction pipe;

[0025] Remove the filling vacuum extraction pipe and close the corresponding external vacuum extraction device, and then return the filling vacuum extraction pipe to the molding sand filling position to wait for the next molding sand filling operation.

[0026] The beneficial effects of the present invention are as follows:

[0027] 1. Utilize the rotation of the three-way pipe to provide power for the power component to make the two closing plates move in opposite directions. One of the closing plates enters the position of the nozzle of the three-way pipe connected to the filling vacuum extraction pipe to block it, and the other closing plate leaves the position of the nozzle of the three-way pipe connected to the pouring vacuum extraction pipe to open it, so as to exchange the positions of the filling vacuum extraction pipe and the pouring vacuum extraction pipe and change their working states, and can keep the inside of the sand box in a vacuum state, avoid the molding sand from loosening and affecting the shape of the molding cavity, and thus ensure the production quality of the casting;

[0028] 2. Utilize the rotation of the three-way pipe to provide power for the power component to move the two closing plates in opposite directions, and no matter whether the three-way pipe rotates clockwise or counterclockwise, the closing plates all move along the required path, making the exchange of the pouring vacuum extraction pipe and the filling vacuum extraction pipe more convenient;

[0029] 3. Use the limiting part to limit the power component to fix the three-way pipe, avoid the internal vacuum state of the mold box from being damaged due to the rotation of the three-way pipe by external force during handling, and at the same time the limiting part can limit the rotation angle of the three-way pipe to make it rotate quantitatively by half a turn, avoid excessive or insufficient rotation of the three-way pipe affecting the blocking and opening degrees of the nozzles of the three-way pipe, and thus ensure the vacuum treatment of the mold box. Description of the Drawings

[0030] Figure 1 Shown is a schematic diagram of the overall structure of the embodiment;

[0031] Figure 2 Shown is the installation position diagram of the holding component in the embodiment;

[0032] Figure 3 Shown is the front view cross-sectional view of the holding component in the embodiment;

[0033] Figure 4 Shown is the installation position diagram of the power component in the embodiment;

[0034] Figure 5 Shown is the installation position diagram of the limiting component in the embodiment.

[0035] In the figure: 10, casting mold box; 11, exhaust pipe; 12, lifting lug; 13, sealing film; 20, holding component; 21, installation pipe; 22, tee pipe; 23, closing plate; 24, power component; 241, fixed gear; 242, auxiliary gear; 243, reciprocating lead screw; 244, moving slider; 245, mounting bracket; 25, limiting component; 251, mounting block; 252, limiting block; 253, limiting groove; 254, rotating rod; 255, knob; 256, return spring; 257, rotating rod; 31, filling and evacuation pipe; 32, pouring and evacuation pipe; 41, lifting base; 42, sling. Detailed implementation manners

[0036] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments and the accompanying drawings of the specification.

[0037] Embodiment

[0038] Figures 1-5 In the V-method casting sand box vacuum holding and transfer system, it is characterized by including:

[0039] A casting mold box 10, the casting mold box 10 being an upper sand box mold or a lower sand box mold, and a through exhaust pipe 11 being provided on one side of the casting mold box 10;

[0040] A holding component 20, the holding component 20 including an installation pipe 21 and a tee pipe 22 that is rotationally sealed with the installation pipe 21, the installation pipe 21 being fixedly connected to the exhaust pipe 11, a power component 24 and two closing plates 23 that reciprocate in the A direction being provided inside the tee pipe 22, and the two closing plates 23 moving in opposite directions;

[0041] Pipeline component, the pipeline component includes a charging vacuum tube 31 and a pouring vacuum tube 32. One end of the charging vacuum tube 31 and the pouring vacuum tube 32 are respectively connected to two pipe orifices of a tee 22, and the other ends of the charging vacuum tube 31 and the pouring vacuum tube 32 are both connected to an external vacuum pumping device;

[0042] After the mold box 10 is transported, the pouring vacuum tube 32 is inserted into the tee 22 and the tee 22 is rotated half a turn. The power member 24 pushes the two closing plates 23 to move in opposite directions. One of the closing plates 23 enters the position of the pipe orifice of the tee 22 connected to the charging vacuum tube 31 to block it, and the other closing plate 23 leaves the position of the pipe orifice of the tee 22 connected to the pouring vacuum tube 32 to open it, and the charging vacuum tube 31 is converted into a pouring vacuum tube 32 to maintain the vacuum inside the mold box 10.

[0043] When the mold box 10 is transported, the charging vacuum tube 31 moves along with the holding assembly 20 and the exhaust pipe 11. After the mold box 10 is transported, the pouring vacuum tube 32 is inserted into the pipe orifice of the tee 22 and the corresponding external vacuum pumping device is connected and opened. Subsequently, the tee 22 is rotated half a turn so that the pouring vacuum tube 32 and the charging vacuum tube 31 exchange positions, and the power member 24 pushes the two closing plates 23 to move in opposite directions. One of the closing plates 23 enters the position of the pipe orifice of the tee 22 connected to the charging vacuum tube 31 to block it, and the other closing plate 23 leaves the position of the pipe orifice of the tee 22 connected to the pouring vacuum tube 32 to open it. The vacuum pumping operation is continuously carried out through the pipe orifice of the tee 22 connected to the pouring vacuum tube 32. Subsequently, the charging vacuum tube 31 is removed and the corresponding external vacuum pumping device is closed, and the charging vacuum tube 31 can return to the molding sand charging position to wait for the next molding sand charging operation.

[0044] Using the rotation of the tee 22 to provide power for the power member 24 to make the two closing plates 23 move in opposite directions. One of the closing plates 23 enters the position of the pipe orifice of the tee 22 connected to the charging vacuum tube 31 to block it, and the other closing plate 23 leaves the position of the pipe orifice of the tee 22 connected to the pouring vacuum tube 32 to open it, so as to exchange the positions of the charging vacuum tube 31 and the pouring vacuum tube 32 and change their working states, and can keep the inside of the sand box in a vacuum state, avoid the molding sand from loosening and affecting the shape of the molding cavity, and further ensure the production quality of the casting.

[0045] A method for maintaining the vacuum during the transfer of a V-process casting sand box includes the following steps,

[0046] S1. Install the pouring vacuum tube 32;

[0047] Fix the pouring vacuum tube 32 at the pouring position to the pipe orifice of the tee 22 and start the external vacuum pumping device connected to the pouring vacuum tube 32;

[0048] S2. Adjust the position of the pouring and evacuation pipe 32;

[0049] Rotate the three-way pipe 22 by half a turn so that the pouring and evacuation pipe 32 and the filling and evacuation pipe 31 exchange positions, and the power member 24 then pushes the two closing plates 23 to move in opposite directions;

[0050] S3. Adjust the evacuation position at the nozzle of the three-way pipe 22;

[0051] One of the closing plates 23 enters the position at the nozzle of the three-way pipe 22 connected to the filling and evacuation pipe 31 to block it, and the other closing plate 23 leaves the position at the nozzle of the three-way pipe 22 connected to the pouring and evacuation pipe 32 to open it, and starts to continuously evacuate through the nozzle of the three-way pipe 22 connected to the pouring and evacuation pipe 32;

[0052] S4. Remove the filling and evacuation pipe 31;

[0053] Remove the filling and evacuation pipe 31 and close the corresponding external evacuation device, and then return the filling and evacuation pipe 31 to the molding sand filling position to wait for the next molding sand filling operation.

[0054] Figures 3-5 In, the power member 24 includes a fixed gear 241 fixedly connected to the installation pipe 21. Both sides of the fixed gear 241 are meshed with auxiliary gears 242. The middle of the auxiliary gear 242 is fixedly connected with a reciprocating lead screw 243. The surface of the reciprocating lead screw 243 is threadedly sleeved with a moving slider 244 fixedly connected to the corresponding closing plate 23.

[0055] One side of the moving slider 244 is movably inserted into an installation frame 245 fixedly connected to the inner wall of the three-way pipe 22, and one section of the installation frame 245 is sleeved on the surface of the reciprocating lead screw 243.

[0056] When the three-way pipe 22 is rotated, the fixed gear 241 connected to the installation pipe 21 remains stationary, and the auxiliary gears 242 then move on the surface of the fixed gear 241 and drive the reciprocating lead screw 243 to rotate. The two moving sliders 244 then move on the surface of the reciprocating lead screw 243 under the limitation of the installation frame 245. The two moving sliders 244 at different positions move the closing plates 23 in different moving directions, so as to block or open the two nozzles of the three-way pipe 22.

[0057] Utilize the rotation of the three-way pipe 22 to provide power for the power member 24 to move the two closing plates 23 in opposite directions, and no matter whether the three-way pipe 22 rotates clockwise or counterclockwise, the closing plates 23 all move along the required path, making the exchange of the pouring and evacuation pipe 32 and the filling and evacuation pipe 31 more convenient.

[0058] Figures 3-5Among them, the holding component 20 further includes a limiting member 25. The limiting member 25 includes a mounting block 251 and two limiting blocks 252. The mounting block 251 is fixedly connected to the fixed gear 241. Limiting grooves 253 corresponding to the limiting blocks 252 are formed on both sides of the mounting block 251. One end of the limiting block 252 is provided with a rotating rod 254. One end of the rotating rod 254 rotatably penetrates through the three-way pipe 22 and extends to the outside. The rotating rod 254 is threadedly sleeved at the insertion part with the three-way pipe 22. A knob 255 is fixedly connected to the end of the rotating rod 254.

[0059] One end of the limiting block 252 is rectangularly arranged, and the rectangular end of the limiting block 252 is movably inserted into the rotating rod 254. A return spring 256 is fixedly connected between the limiting block 252 and the rotating rod 254. The other end of the limiting block 252 is in a slope shape. Rotating rods 257 matching the slope ends of the limiting blocks 252 are arranged on both sides of the limiting block 252 where the limiting grooves 253 are located.

[0060] When the three-way pipe 22 is rotated clockwise or counterclockwise, rotate the corresponding knob 255 to drive the rotating rod 254 to rotate. The limiting block 252 rotates accordingly, changing the orientation of the slope end of the limiting block 252. Then the limiting member 25 no longer restricts the holding component 20. When the three-way pipe 22 is rotated, the two limiting blocks 252 are squeezed by the rotating rod 254 corresponding to their slope ends. The limiting blocks 252 contract back into the rotating rod 254 and compress the return spring 256. Then, rotate the rotating rod 254 and the limiting block 252 back through the knob 255. When the limiting block 252 moves to the position of another limiting groove 253, the return spring 256 in the compressed state pushes the limiting block 252 into the limiting groove 253. The two limiting blocks 252 block the clockwise and counterclockwise rotation trends of the three-way pipe 22 again, avoiding the destruction of the internal vacuum state of the mold box 10 due to the rotation of the three-way pipe 22 during handling.

[0061] The power component 24 is restricted by the limiting member 25 to fix the three-way pipe 22, avoiding the destruction of the internal vacuum state of the mold box 10 due to the rotation of the three-way pipe 22 by external force during handling. At the same time, the limiting member 25 can limit the rotation angle of the three-way pipe 22, making it rotate quantitatively by half a week, avoiding the excessive or insufficient rotation of the three-way pipe 22 from affecting the sealing and opening degree of the pipe orifice of the three-way pipe 22, so as to ensure the vacuum pumping treatment of the mold box 10.

[0062] Figures 1-3 Among them, the preliminary vacuum pumping pipe is used for the internal sand filling of the mold box 10 and the vacuum extraction and maintenance inside the mold box 10 during the handling of the mold box 10. The pouring vacuum pumping pipe 32 is used for maintaining the internal vacuum of the mold box 10 during the product casting and cooling processes.

[0063] A sealing film 13 is provided at both the bottom and the top of the mold box 10, and molding sand is filled between the inner mold box 10 and the two sealing films 13.

[0064] The preliminary evacuation tube is used for evacuating and maintaining the vacuum inside the mold box 10 during the filling of the molding sand inside the mold box 10 and the handling of the mold box 10, ensuring that the environment inside the sand box reaches a certain purification level to prevent impurities in the outside air from entering the casting metal, thereby affecting the quality of the final casting. The pouring evacuation tube 32 is used for maintaining the vacuum inside the mold box 10 during the casting and cooling of the product. Keeping the sand box evacuated during casting and cooling helps reduce the dissolution of gas and porosity in the casting, improve the density and uniformity of the casting, promote the uniform cooling of the casting and reduce internal stress during cooling, reduce the deformation of the casting and improve its structural strength.

[0065] Figure 1 It further includes a transfer assembly. The transfer assembly includes a lifting base 41 connected to an external lifting device. A plurality of slings 42 are provided at the bottom of the lifting base 41. The slings 42 lift and transfer the mold box 10 through the lifting lugs 12 on the surface of the mold box 10.

[0066] The plurality of slings 42 are respectively sleeved on the lifting lugs 12 on the surface of the mold box 10, and the external lifting device drives the mold box 10 to perform handling work through the lifting base 41.

[0067] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it.

Claims

1. V-method casting sand box vacuum holding transfer system, characterized in that: include: A casting mold box (10), wherein the casting mold box (10) is a sand box upper mold or a sand box lower mold, and a through exhaust pipe (11) is provided on one side of the casting mold box (10); A retaining assembly (20), the retaining assembly (20) comprising a mounting tube (21) and a three-way tube (22) rotatably sealed with the mounting tube (21), the mounting tube (21) being fixedly connected to the exhaust pipe (11), the three-way tube (22) being internally provided with a power member (24) and two closing plates (23) reciprocating in direction A, the two closing plates (23) moving in opposite directions; A pipeline assembly, the pipeline assembly comprising a loading vacuum tube (31) and a pouring vacuum tube (32), one end of the loading vacuum tube (31) and the pouring vacuum tube (32) are respectively connected to two pipe openings of a three-way pipe (22), and the other ends of the loading vacuum tube (31) and the pouring vacuum tube (32) are connected to an external vacuum device; After the transport of the casting mold box (10) is completed, the pouring vacuum tube (32) is loaded into the three-way tube (22) and the three-way tube (22) is rotated half a circle, and the power member (24) pushes the two closing plates (23) to move in the opposite direction, one of the closing plates (23) enters the pipe mouth of the three-way tube (22) connected to the loading vacuum tube (31) to block it, and the other closing plate (23) leaves the pipe mouth of the three-way tube (22) connected to the pouring vacuum tube (32) to open it, and the loading vacuum tube (31) is converted into the pouring vacuum tube (32) to maintain the vacuum inside the casting mold box (10).

2. The V-method casting sand box vacuum holding and transporting system according to claim 1 is characterized in that: The power member (24) comprises a fixed gear (241) fixedly connected to the mounting tube (21), auxiliary gears (242) are meshedly connected to both sides of the fixed gear (241), a reciprocating screw rod (243) is fixedly connected to the middle of the auxiliary gear (242), and a movable slider (244) fixedly connected to the corresponding closing plate (23) is threadedly sleeved on the surface of the reciprocating screw rod (243).

3. The V-method casting sand box vacuum holding and transporting system according to claim 2 is characterized in that: A mounting frame (245) fixedly connected to the inner wall of the three-way pipe (22) is movably inserted on one side of the movable slide block (244), and a section of the mounting frame (245) is sleeved on the surface of the reciprocating screw rod (243).

4. The V-method casting sand box vacuum holding and transporting system according to claim 2 is characterized in that: The retaining assembly (20) further comprises a limiting member (25), the limiting member (25) comprising a mounting block (251) and two limiting blocks (252), the mounting block (251) being fixedly connected to the fixed gear (241), limiting grooves (253) corresponding to the limiting blocks (252) being provided on both sides of the mounting block (251), a rotating rod (254) being provided at one end of the limiting block (252), one end of the rotating rod (254) being rotatably inserted through the three-way pipe (22) and extending to the outside, the rotating rod (254) being threadedly sleeved at the insertion point of the three-way pipe (22), and a knob (255) being fixedly connected to the end of the rotating rod (254).

5. The V-method casting sand box vacuum holding and transporting system according to claim 4 is characterized in that: One end of the limit block (252) is rectangular, and the rectangular end of the limit block (252) is movably inserted into the rotating rod (254). A return spring (256) is fixedly connected between the limit block (252) and the rotating rod (254). The other end of the limit block (252) is sloped, and the limit groove (253) is located on both sides of the limit block (252). Rotating rods (257) matching the slope end of the limit block (252) are provided.

6. The V-method casting sand box vacuum holding and transporting system according to claim 5 is characterized in that: The preliminary vacuuming pipe is used for extracting and maintaining the vacuum inside the mold box (10) during the filling of molding sand inside the mold box (10) and the transportation of the mold box (10), and the pouring vacuuming pipe (32) is used for maintaining the vacuum inside the mold box (10) during the product casting and cooling process.

7. The V-method casting sand box vacuum holding and transporting system according to claim 1 is characterized in that: The bottom and top of the casting mold box (10) are both provided with sealing films (13), and the space between the inner casting mold box (10) and the two sealing films (13) is filled with molding sand.

8. The V-method casting sand box vacuum holding and transporting system according to claim 1, characterized in that: It also includes a transfer component, which includes a lifting base (41) connected to an external lifting device, and a plurality of slings (42) are arranged at the bottom of the lifting base (41). The slings (42) lift and transfer the mold box (10) through the lifting ears (12) on the surface of the mold box (10).

9. The method for transporting a V-process casting sand box while maintaining vacuum according to any one of claims 1 to 8, characterized in that: The following steps are included: S1, installing the pouring vacuum pipe (32); The pouring vacuum pumping pipe (32) at the pouring position is fixedly connected to the pipe opening of the three-way pipe (22), and the external vacuum pumping device connected to the pouring vacuum pumping pipe (32) is started; S2, adjusting the position of the pouring vacuum pipe (32); The three-way pipe (22) is rotated to make it rotate half a circle, and the pouring vacuum pipe (32) and the filling vacuum pipe (31) are exchanged, and the power member (24) pushes the two closing plates (23) to move in the opposite direction; S3, adjusting the exhaust position of the three-way pipe (22); One of the sealing plates (23) enters the pipe opening of the three-way pipe (22) connected to the filling vacuum pumping pipe (31) to seal it, and the other sealing plate (23) leaves the pipe opening of the three-way pipe (22) connected to the pouring vacuum pumping pipe (32) to open it, and starts to continuously perform the vacuum pumping operation through the pipe opening of the three-way pipe (22) connected to the pouring vacuum pumping pipe (32); S4, dismantling and filling the vacuum tube (31); The filling vacuum pumping tube (31) is removed and the corresponding external vacuum pumping device is turned off, and then the filling vacuum pumping tube (31) is returned to the molding sand filling position to wait for the next molding sand filling work.

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