Auxiliary device for testing dehydration rate of VRH sodium silicate sand mold and molding equipment

Abstract

The utility model discloses an auxiliary device for testing the dehydration rate of a VRH sodium silicate sand mold and molding equipment, the auxiliary device comprises a sand storage cylinder, a cover body, a one-way valve mechanism and an air inlet mechanism, the cover body is used for sealing the sand storage cylinder, a valve plate is arranged on the cover body, and the one-way valve mechanism is connected with the valve plate and used for opening or closing the valve plate; the air inlet mechanism is connected with the sand storage cylinder and provided with an air inlet valve used for controlling air to enter the sand storage cylinder. As the one-way valve mechanism is arranged at the upper part of the sand storage cylinder in the appliance, when the appliance is arranged in the vacuum box and the exterior of the appliance is in a vacuum state, as the pressure in the sand storage cylinder is higher than that of the exterior, the one-way valve is opened, and molding sand in the cylinder is dehydrated in the vacuum state; when the vacuum dehydration procedure is finished and the vacuum box is filled with gas, the pressure outside the sand storage cylinder is higher than that inside the sand storage cylinder, the one-way valve is closed, and the dehydration rate data can be calculated by weighing the device and the molding sand together.

Description

Technical Field

[0001] The utility model relates to the technical field of sodium silicate casting sand molds, and particularly to an auxiliary device and a molding device for testing the dehydration rate of VRH sodium silicate sand molds. Background Technique

[0002] VRH (Vacuum Replace Hardening) is a special technology for sodium silicate casting sand molds. Sodium silicate is the common name of water-soluble sodium silicate solution, which is used as a binder in casting production and mixed into molding sand, and then cured by a certain method to obtain a sand mold with a certain strength. The hardening of sodium silicate sand was first carried out by blowing CO2, and later vacuum methods and ester hardening methods were developed.

[0003] When the amount of sodium silicate added to the molding sand is certain, the strength of the sand mold obtained by the vacuum method can be 5 to 10 times or more that of the CO2 blowing method; but to completely harden the sand mold of the same volume, the ordinary CO2 method takes less time while the vacuum method takes too long. Therefore, foundry technicians combine the two methods. When the amount of sodium silicate added to the sand mold is relatively small (generally 50% - 60% of the amount used in the CO2 blowing method), first evacuate to dehydrate the sodium silicate to a certain extent, and then blow CO2 to completely harden the sand mold, aiming to obtain a higher sand mold strength in a shorter time with less sodium silicate added. This hardening process of sodium silicate sand mold under vacuum conditions is simply called the VRH process. Advantages of the VRH process: ① Reduce the amount of sodium silicate added to the sand mold, and at the same time, the consumption of CO2 is significantly saved compared with the manual blowing method; ② The molding sand has good fluidity and is easy to mold and compact; ③ Improve the air permeability, collapsibility and collapsibility of the sand mold; ④ Improve the reusability of the used sand, and the recovery rate of the used sand reaches 85%

[0004] or more; ⑤ Improve the product quality. Therefore, the VRH process is an important technology in the casting industry.

[0005] During this process, the sand mold with sodium silicate (also known as water glass, mainly composed of sodium silicate) as the binder needs to be evacuated. The process is: the casting model and the sand box are placed on the front motorized roller table → the mixer fills the sand → the sand box enters the vacuum box → the vacuum pump evacuates to dehydrate the sand mold → CO2 is filled to finally cure the sand mold. When evacuating the sand mold in the vacuum box, when the pressure in the box reaches the water saturation vapor pressure at the current temperature, the water in the sand mold will vaporize and be pumped out, so as to dehydrate the sand mold. The dehydration rate of the sand mold is an important parameter in VRH. A suitable dehydration rate is beneficial to ensuring the strength and comprehensive quality of the sand mold, and also has a certain impact on the production economic benefits. In addition, the dehydration rate data is an important basis for the selection of vacuum pump equipment and the design of the equipment system.

[0006] However, in actual production, the volume of the vacuum box is relatively large, generally 10m3 As mentioned above, it is very difficult to obtain the dehydration rate because the dehydration process is completed in a large sealed box. Moreover, vacuum dehydration is only one step in the VRH process. After vacuum dehydration is completed, CO2 gas is immediately filled into the vacuum box, and then air is filled to completely release the vacuum before the vacuum box is opened to take out the sand mold. The entire process is completed inside the vacuum box. After vacuum dehydration, when CO2 gas and air are filled, the water glass in the molding sand will undergo complex chemical and physical reactions. The sand mold after dehydration will absorb the CO2 gas and moisture in the air, and its composition and weight will change significantly. Therefore, so far, there is no effective detection method for the VRH dehydration rate data in actual production. Summary of the Invention

[0007] The present invention provides an auxiliary device for testing the dehydration rate of VRH sodium silicate sand molds to solve the technical problem in the prior art that the dehydration rate of the molding sand cannot be accurately measured during the vacuum pumping process of the sand mold.

[0008] The present invention also provides a molding equipment, including a VRH vacuum box, and the auxiliary device for testing the dehydration rate of VRH sodium silicate sand molds is arranged inside the VRH vacuum box.

[0009] According to one aspect of the present invention, there is provided

[0010] An auxiliary device for testing the dehydration rate of VRH sodium silicate sand molds, which is used to be arranged inside a vacuum box to dehydrate the molding sand through the vacuum box. The auxiliary device includes a sand storage cylinder, a cover body, a one-way valve mechanism and an air inlet mechanism. The sand storage cylinder includes a receiving cavity for placing the molding sand, the cover body is used to seal the receiving cavity, and a valve plate is arranged on the cover body. The one-way valve mechanism is connected to the valve plate and is used to automatically open the valve plate from the inside out under the action of negative pressure when the vacuum box is evacuated, and the one-way valve mechanism is also used to automatically close the valve plate when the vacuum box stops evacuating; the air inlet mechanism is connected to the sand storage cylinder, and the air inlet mechanism is provided with an air inlet valve for controlling the air to enter the receiving cavity.

[0011] Preferably, the one-way valve mechanism includes a lead wire and a weight assembly. The valve plate is connected to the weight assembly through the lead wire. The valve plate is used to press on the cover body by its own weight to seal the receiving cavity, and the weight assembly is used to pull the valve plate along the opening direction of the valve plate. The pulling force of the weight assembly on the valve plate is less than the weight of the valve plate.

[0012] Preferably, the one-way valve mechanism further includes a linear bearing, and the linear bearing is installed in the sleeve of the cover body through a set screw and is connected to the valve plate.

[0013] Preferably, the counterweight assembly includes a first guide wheel, a second guide wheel and a counterweight. The first guide wheel is rotatably mounted directly above the valve plate. The second guide wheel is arranged on one side of the first guide wheel and avoids directly above the valve plate. The lead wire is sequentially wound around the first guide wheel and the second guide wheel. The valve plate is hung on the first end of the lead wire, and the second end of the lead wire is hung with the counterweight after being redirected through the first guide wheel and the second guide wheel respectively.

[0014] Preferably, the counterweight assembly further includes a counterweight retaining ring installed on the cover body. The counterweight retaining ring includes a limiting hole adapted to the outer shape of the counterweight. The counterweight is inserted into the limiting hole and is used to move along the guiding of the limiting hole.

[0015] Preferably, the auxiliary appliance further includes an upper plate, a bottom plate and a locking mechanism. The sand storage cylinder is arranged between the upper plate and the bottom plate, and the locking mechanism is used to lock the upper plate and the cover body to each other.

[0016] Preferably, the auxiliary appliance further includes a lifting base arranged below the bottom plate. A pull rod is also arranged between the upper plate and the bottom plate. The pull rod extends downward to below the bottom plate and is connected to the lifting base. The lifting base is used to adjust the support height of the pull rod.

[0017] Preferably, the pull rod extends upward to protrude from the surface of the upper plate facing the cover body, and a positioning hole corresponding to the pull rod is provided on the cover body.

[0018] Preferably, the intake valve is arranged on the bottom plate. An air passage connected to the intake valve is provided in the bottom plate, and the intake valve and the air passage are connected through an intake valve joint.

[0019] According to another aspect of the present invention, there is also provided a molding device, including a VRH vacuum box, and further including an auxiliary appliance for testing the dehydration rate of VRH sodium silicate sand mold. The auxiliary appliance is arranged in the VRH vacuum box.

[0020] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0022] Figure 1 It is a schematic external structure diagram of an auxiliary appliance for testing the dehydration rate of VRH sodium silicate sand mold.

[0023] Figure 2Schematic top view structure diagram of an auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold

[0024] Figure 3 Schematic A-A sectional structure diagram of an auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold

[0025] Figure 4 Schematic B-B sectional structure diagram of an auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold

[0026] 1. Sand storage cylinder; 2. Upper plate; 3. Bottom plate; 4. Adjustable base; 5. Tie rod; 6. Intake valve; 7. Buckle; 8. Upper plate buckle seat; 9. Cover body buckle seat; 10. Cover body; 11. Valve plate; 12. Setscrew; 13. Upper end cover of bearing; 14. First guide wheel; 15. Lead wire; 16. Fixing screw; 17. Weight retaining ring; 18. Guide wheel frame; 19. Second guide wheel; 20. Screws with holes; 21. Weight; 22. Linear bearing; 23. Sealing ring; 24. Air vent plug; 25. Intake valve joint Specific embodiments

[0027] The following will describe the embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention can be implemented in many different ways defined and covered by the following

[0028] According to one aspect of the present invention, referring to Figure 1 and Figure 2 , an auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold (hereinafter referred to as "auxiliary device") is provided, which is used to be arranged in a vacuum chamber to dehydrate molding sand through the vacuum chamber. The auxiliary device includes a sand storage cylinder 1, a cover body 10, a one-way valve mechanism and an air intake mechanism. The sand storage cylinder 1 includes a receiving cavity for placing molding sand. The cover body 10 is used to seal the receiving cavity. A valve plate 11 is provided on the cover body 10. The one-way valve mechanism is connected to the valve plate 11. The one-way valve mechanism is used to automatically open the valve plate 11 from the inside to the outside under the action of negative pressure when the vacuum chamber is evacuated. The one-way valve mechanism is also used to automatically close the valve plate 11 when the vacuum chamber stops evacuating; The air intake mechanism is connected to the sand storage cylinder 1, and the air intake mechanism is provided with an intake valve 6 for controlling the air to enter the sand storage cylinder 1

[0029] The total weight of the above-mentioned appliance is about 3 kg. The sand storage cylinder 1 is made of high-strength glass tube, and the main body of the appliance is made of hard aluminum alloy, meeting the usage conditions in a vacuum environment. The sand storage cylinder 1 is used to fill the casting sand for testing inside (this kind of sand is mixed with sodium silicate binder and is generally called molding sand). The cover 10 is used to seal the sand storage cylinder 1. A sealing ring is provided between the cover 10 and the sand storage cylinder 1 to make the connection between the cover 10 and the sand storage cylinder 1 tight and avoid air leakage. The one-way valve mechanism is used to make the valve plate 11 open unidirectionally from the inside to the outside when the appliance is placed in a vacuum chamber for dehydration of the molding sand, facilitating vacuum dehydration. After the vacuum dehydration is completed, the one-way valve mechanism closes the valve plate 11 under the action of air pressure, and then the casting sand in the sand storage cylinder 1 can be kept in a vacuum dehydration state. The air intake mechanism is used to open the intake valve 6 after vacuum dehydration to allow air to enter the sand storage cylinder 1 and open the valve plate 11. When in use, the appliance is placed in the vacuum chamber together with the casting sand box as a whole, and the VRH hardening process is carried out together with the sand box. The molding sand loaded into the sand storage cylinder 1 should be accurately weighed (generally 1000 grams by integer weight). The appliance filled with molding sand is weighed as a whole before being placed in the vacuum chamber and weighed as a whole again after being taken out of the vacuum chamber. In this way, the weight of the water removed from the molding sand under the action of vacuum can be calculated, and then the dehydration rate can be calculated.

[0030] For the appliance used in a vacuum environment as described above, since a one-way valve mechanism is provided at the upper part of the sand storage cylinder 1, when the appliance is placed in a vacuum chamber, when the outside of the appliance is in a vacuum state, due to the pressure inside the sand storage cylinder 1 being higher than the outside, the one-way valve opens, and the molding sand inside the cylinder is dehydrated in a vacuum state; when the vacuum dehydration program ends and gas is filled into the vacuum chamber, the pressure outside the sand storage cylinder 1 is higher than the inside, causing the one-way valve to close, and the dehydration rate data can be calculated by weighing the appliance and the molding sand together.

[0031] The utility model has the characteristics of simple operation, low manufacturing cost of the appliance, and good practicability.

[0032] Optionally, the one-way valve mechanism includes a lead wire 15 and a weight assembly, the valve plate 11 is connected to the weight assembly through the lead wire 15, the valve plate 11 is used to be pressed on the cover body 10 by its own weight to achieve the sealing of the receiving cavity, the weight assembly is used to pull the valve plate 11 along the opening direction of the valve plate 11, and the traction force of the weight assembly on the valve plate 11 is less than the weight of the valve plate 11. The one-way valve mechanism also includes a linear bearing 22, the linear bearing 22 is installed in the sleeve of the cover body 10 through the top screw 12, and the linear bearing 22 is connected to the valve plate 11. A retaining structure is provided on the top of the cover body 10, and a sleeve is provided in the center of the retaining structure. A linear bearing 22 is installed in the sleeve. The linear bearing 22 is connected to the valve plate 11, and the valve plate 11 is connected to the counterweight assembly through a lead 15. When the valve plate 11 is opened or closed under the action of external pressure, the valve plate 11 and the counterweight assembly form a lever principle through the lead 15, which facilitates the opening and closing of the valve plate 11. The valve plate 11 is installed on the linear bearing 22. The linear bearing 22 guides the movement of the valve plate 11 and can reduce the friction when the valve plate 11 moves. Optionally, see Figure 1 The counterweight assembly includes a first guide wheel 14, a second guide wheel 19 and a counterweight 21. The first guide wheel 14 is rotatably mounted directly above the valve plate. The second guide wheel 19 is arranged on one side of the first guide wheel 14 and avoids directly above the valve plate 11. The lead wire 15 is sequentially wound around the first guide wheel 14 and the second guide wheel 19. The valve plate 11 is hung on the first end of the lead wire 15. The second end of the lead wire 15 is hung on the counterweight 21 after switching through the first guide wheel 14 and the second guide wheel 19 respectively. The first guide wheel 14 is mounted on the bearing upper end cover 13 above the linear bearing 22 through the guide wheel frame 18, and the second guide wheel 19 is mounted on the cover body 10 through the guide wheel frame 18. Specifically, the second guide wheel 19 is mounted on the enclosure structure, one end of the lead wire 15 is fixed to the valve plate 11 through a hole screw 20, and the other end is fixed to the counterweight 21 through a hole screw 20. Through the arrangement of the first guide wheel 14 and the second guide wheel 19, the friction force can be reduced, and the valve plate 11 can be opened and closed quickly, thereby improving the detection accuracy.

[0033] Optionally, the counterweight assembly further includes a counterweight retaining ring 17 mounted on the cover 10. The counterweight retaining ring 17 includes a limiting hole adapted to the outer shape of the counterweight 21. The counterweight 21 is inserted into the limiting hole and is adapted to move along the guiding of the limiting hole. The counterweight retaining ring 17 is mounted on the surrounding structure of the cover 10 by fixing screws 16. In a preferred embodiment, the second guide wheel 19 can also be mounted on the counterweight retaining ring 17 through a guide wheel bracket 18, so that the second guide wheel 19 and the counterweight 21 are kept in a vertical line. When the appliance is in use, molding sand containing sodium silicate binder for casting is loaded into the sand storage cylinder 1, and then the sand storage cylinder 1 is placed into a vacuum chamber. In the VRH process, the vacuum is first pumped to a high vacuum level, then carbon dioxide is filled to a medium vacuum level, and finally the atmosphere is introduced to equalize the pressure inside and outside the vacuum chamber before opening the vacuum chamber. This process can harden the sand mold. However, since the casting sand absorbs carbon dioxide, its weight will increase, and the dehydration rate at high vacuum cannot be known. By adjusting the counterweight 21, a slight pressure difference inside and outside the sand storage cylinder 1 can open or close the valve cover. The sand in the sand storage cylinder 1 contains water, and at high vacuum, the water will vaporize, increasing the pressure inside the sand storage cylinder 1. When the pressure inside the sand storage cylinder 1 is greater than the external pressure, the valve cover is pushed open; when carbon dioxide is introduced into the vacuum chamber, the pressure outside the sand storage cylinder 1 rises rapidly, making the pressure outside the sand storage cylinder 1 greater than the pressure inside, and quickly closing the valve cover, so that the sand in the cylinder remains in the state after vacuum dehydration until the appliance is taken out of the vacuum chamber and weighed after the vacuum chamber is opened, and the dehydration rate data can be obtained. The significance of measuring the dehydration rate is that the size of the dehydration rate is closely related to the strength of the sand mold.

[0034] Optionally, referring to Figure 1 , the auxiliary appliance further includes an upper plate 2, a bottom plate 3 and a locking mechanism. The sand storage cylinder 1 is disposed between the upper plate 2 and the bottom plate 3, and the locking mechanism is used to lock the upper plate 2 and the cover 10 to each other. The sand storage cylinder 1 is disposed inside the upper plate 2, and a bottom plate 3 is provided at the bottom of the sand storage cylinder 1. The upper plate 2 and the cover 10 are provided with a locking mechanism that cooperates with each other. The upper plate 2 is used to support the sand storage cylinder 1 and is also convenient for covering the cover 10 through the locking mechanism. The locking mechanism includes a buckle 7 and an upper plate buckle seat 8 provided on the upper plate 2, and a cover body buckle seat 9 provided on the cover 10. The buckle 7 and the upper plate buckle seat 8 on the upper plate 2 are used to fasten and fix the cover 10 on the upper plate 2. When sand needs to be filled into the sand storage cylinder 1 or the sand in the sand storage cylinder 1 needs to be taken out, the buckle 7 can be opened. When the sand is loaded and needs to be sent into the vacuum chamber, the buckle 7 should be fastened.

[0035] Optionally, referring to Figure 1, the auxiliary appliance further includes a lifting base 4 disposed below the bottom plate 3. A pull rod 5 is further provided between the upper plate 2 and the bottom plate 3. The pull rod 5 extends downward to the lower side of the bottom plate 3 and is connected to the lifting base 4. The lifting base 4 is used to adjust the support height of the pull rod 5. The pull rod 5 is disposed between the upper plate 2 and the bottom plate 3 to play a supporting role. In addition, the pull rod 5 is connected to the lifting base 4, and the pull rod 5 is tightened by the lifting base 4 to press the rubber sealing rings 23 above and below the sand storage cylinder 1, playing a sealing role. In addition, referring to Figure 3 , rubber sealing rings 23 are provided between the valve plate 11 and the cover body 10, between the cover body 10 and the upper plate 2, and between the sand storage cylinder 1 and the bottom plate 3, playing a sealing role.

[0036] Optionally, the pull rod 5 extends upward to the upper plate 2 and protrudes from one side of the upper plate 2 facing the cover body 10. The cover body 10 is provided with positioning holes corresponding to the protruding part of the pull rod 5. The pull rod 5 cooperates with the four positioning holes of the cover body 10 through its upper protruding part, playing a positioning role for the upper cover.

[0037] Optionally, referring to Figure 4 , the air inlet valve 6 is disposed on the bottom plate 3. An air passage connected to the air inlet valve 6 is provided inside the bottom plate 3. The air inlet valve 6 and the air passage are connected through an air inlet valve joint 25. An air passage is provided inside the bottom plate 3. Correspondingly, a controllable air inlet valve 6 is installed on one side of the bottom plate 3. After the test molding sand in the sand storage cylinder 1 is dehydrated, due to the action of the one-way dehydration mechanism, when the entire appliance is taken out of the vacuum chamber, the inside of the sand storage cylinder 1 is in a vacuum state. At this time, weighing the entire appliance can know how much water the molding sand has lost. Then, the air inlet valve 6 is opened, and air enters the sand storage cylinder 1, so that the valve plate 11 can be opened.

[0038] Optionally, referring to Figure 4 , a breather plug 24 is provided at the connection between the air passage and the sand storage cylinder 1. The breather plug 24 plays a role in preventing sand from entering the air passage to protect the air passage.

[0039] An embodiment of the second aspect of the present invention provides a molding device, including a VRH vacuum chamber, and the auxiliary appliance for testing the dehydration rate of VRH sodium silicate sand mold is disposed in the VRH vacuum chamber. When the auxiliary appliance is placed in the vacuum chamber of the VRH molding device, when the outside of the appliance is in a vacuum state, since the pressure inside the sand storage cylinder 1 is higher than the outside, the one-way valve is opened, and the molding sand in the cylinder is dehydrated in a vacuum state; when the vacuum dehydration program ends and gas is filled into the vacuum chamber, the pressure outside the sand storage cylinder 1 is higher than the inside, so that the one-way valve is closed. When using this VRH molding device for sodium silicate casting sand molds, the dehydration rate of the sand mold can be accurately measured.

[0040] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An auxiliary device for testing the dehydration rate of VRH sodium silicate sand molds, which is used to be arranged in a vacuum chamber to dehydrate the molding sand through the vacuum chamber, and is characterized in that, The auxiliary device comprises a sand storage cylinder (1), a cover body (10), a one-way valve mechanism and an air intake mechanism. The sand storage cylinder (1) comprises a receiving chamber for placing molding sand. The cover body (10) is used to seal the receiving chamber. A valve plate (11) is provided on the cover body (10). The one-way valve mechanism is connected to the valve plate (11). The one-way valve mechanism is used to automatically open the valve plate (11) from the inside to the outside under the action of negative pressure when the vacuum box is evacuated. The one-way valve mechanism is also used to automatically close the valve plate (11) when the vacuum box stops evacuating. The air intake mechanism is connected to the sand storage cylinder (1). The air intake mechanism is provided with an air intake valve (6) for controlling the air to enter the receiving chamber.

2. The auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold according to claim 1, characterized in that, The one-way valve mechanism comprises a lead wire (15) and a counterweight assembly, the valve plate (11) is connected to the counterweight assembly via the lead wire (15), the valve plate (11) is used to be pressed onto the cover body (10) by its own weight to achieve sealing of the receiving cavity, the counterweight assembly is used to pull the valve plate (11) along the opening direction of the valve plate (11), and the traction force of the counterweight assembly on the valve plate (11) is less than the weight of the valve plate (11).

3. The auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold according to claim 2, characterized in that, The one-way valve mechanism further comprises a linear bearing (22), wherein the linear bearing (22) is installed in a sleeve of the cover body (10) via a top screw (12), and the linear bearing (22) is connected to the valve plate (11).

4. The auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold according to claim 2, wherein The counterweight assembly comprises a first guide wheel (14), a second guide wheel (19) and a counterweight (21); the first guide wheel (14) is rotatably mounted directly above the valve plate (11); the second guide wheel (19) is arranged on one side of the first guide wheel (14) and avoids directly above the valve plate (11); the lead wire (15) is sequentially wound around the first guide wheel (14) and the second guide wheel (19); the valve plate (11) is hung on the first end of the lead wire (15); and the second end of the lead wire (15) is hung on the counterweight (21) after being switched through the first guide wheel (14) and the second guide wheel (19).

5. The auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold according to claim 4, characterized in that, The counterweight assembly further comprises a counterweight retaining ring (17) mounted on the cover body (10), the counterweight retaining ring (17) comprising a limiting hole adapted to the outer shape of the counterweight (21), the counterweight (21) being inserted into the limiting hole and used for guiding movement along the limiting hole.

6. The auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold according to claim 1, wherein The auxiliary device further comprises an upper plate (2), a bottom plate (3) and a locking mechanism, wherein the sand storage cylinder (1) is arranged between the upper plate (2) and the bottom plate (3), and the locking mechanism is used to lock the upper plate (2) and the cover body (10) to each other.

7. The auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold according to claim 6, wherein The auxiliary device also includes a lifting base (4) arranged below the bottom plate (3), and a pull rod (5) is also provided between the upper plate (2) and the bottom plate (3). The pull rod (5) extends downward to the bottom of the bottom plate (3) and is connected to the lifting base (4). The lifting base (4) is used to lift and adjust the support height of the pull rod (5).

8. The auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold according to claim 7, characterized in that The pull rod (5) extends upward to protrude from a side of the upper plate (2) facing the cover body (10), and a positioning hole corresponding to the pull rod (5) is provided on the cover body (10).

9. The auxiliary device for testing the dehydration rate of VRH sodium silicate sand mold according to claim 1, wherein, The intake valve (6) is arranged on the bottom plate (3). An air passage connected to the intake valve (6) is provided inside the bottom plate (3). The intake valve (6) and the air passage are connected through an intake valve joint (25).

10. A shaping device, including a VRH vacuum chamber, characterized in that, It further includes an auxiliary appliance for testing the dehydration rate of VRH sodium silicate sand mold as described in any one of claims 1-9, and the auxiliary appliance is arranged inside the VRH vacuum chamber.

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