A large sand casting fast cooling sand box device

Abstract

The utility model relates to a kind of large sand casting quick cooling sand box device, including lower mould sand box and sealing upper mould sand box on lower mould sand box, the inner cavity of lower mould sand box and upper mould sand box is placed with mould sand, the bottom surface of lower mould sand box is equipped with negative pressure bin, the top surface of negative pressure bin is installed with the filter screen of rectangular shape, the outside of negative pressure bin is connected with the suction connection pipe that makes negative pressure form in negative pressure bin.The utility model is drawn by suction interface to the negative pressure bin and makes the negative pressure form in negative pressure bin, realize the sand mould in lower mould sand box and upper mould sand box and air rapid emptying, improve the movement speed of metal atom in casting and heat exchange effect in metal liquid flow process, accelerate the filling of molten iron and cooling speed, shorten the casting opening time, improve production efficiency;At the same time, the problem of air pollution formed by gas produced by binder decomposition directly discharged into atmosphere after mould sand heated in pouring process and solidification process is also effectively solved.

Description

Technical Field

[0001] This utility model relates to the field of sand casting technology, and in particular to a rapid cooling sand box device for large sand castings. Background Technology

[0002] When producing large sand castings using sand casting technology, a large amount of sand is often used to ensure that the sand mold has sufficient strength and to prevent the molding sand from falling off due to impact or high temperature during mold closing or pouring.

[0003] However, a larger sand intake will correspondingly slow down the cooling rate of the casting, hindering the release of air from the sand mold cavity during pouring and the gas generated by the decomposition of the binder in the molding sand during solidification. This makes the casting prone to casting defects such as porosity, sand adhesion, shrinkage cavities, and shrinkage porosity, affecting the internal quality of the casting. Moreover, during the pouring and solidification processes, the harmful gases generated by the thermal decomposition of the binder in the molding sand will be directly released into the atmosphere, easily causing air pollution, which is detrimental to the environment and harmful to the health of operators. Summary of the Invention

[0004] The technical problem to be solved by this utility model is: in order to overcome the shortcomings of the prior art, this utility model provides a rapid cooling sand box device for large sand castings, so as to realize the rapid venting of air in the sand mold in the lower and upper sand boxes, improve the heat exchange between metal atoms and molten metal during the flow process, accelerate the filling and cooling speed of molten iron, shorten the casting unpacking time, and improve production efficiency.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a rapid cooling sand box device for large sand castings, including a lower sand box and an upper sand box sealed and enclosed on the lower sand box. Molding sand is placed in the inner cavity of both the lower and upper sand boxes. A negative pressure chamber is provided on the bottom surface of the lower sand box. A rectangular filter screen is installed on the top surface of the negative pressure chamber. An air extraction pipe is connected to the outer side of the negative pressure chamber to form a negative pressure inside the negative pressure chamber.

[0006] Specifically, a lower sealing groove is provided on the parting surface at the upper end of the lower molding sand box, and an upper sealing groove is provided on the parting surface at the lower end of the upper molding sand box. The sealing strip used for sealing the box is located in the space enclosed by the lower sealing groove and the upper sealing groove.

[0007] Preferably, the lower sand box, upper sand box, and negative pressure chamber all have rectangular cross-sections.

[0008] Furthermore, to ensure that all the air contained in the sand molds in the lower and upper sand boxes passes through the filter screens and enters the negative pressure chamber, the bottom dimension of the lower sand box is larger than the size of the filter screen.

[0009] The beneficial effects of this invention are as follows: This invention creates negative pressure in the negative pressure chamber by evacuating air through the evacuation port, thereby enabling the rapid evacuation of air from the sand molds in the lower and upper sand mold boxes. This improves the rapid movement of metal atoms in the casting and the heat exchange effect during the flow of molten metal, accelerates the filling and cooling speed of molten iron, shortens the casting unpacking time, and improves production efficiency. At the same time, it can also effectively solve the problem of air pollution caused by the direct release of gases generated after the binder decomposes when the molding sand is heated during the pouring and solidification processes into the atmosphere. Attached Figure Description

[0010] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0011] Figure 1 This is a three-dimensional exploded view of the present invention.

[0012] Figure 2 This is an exploded structural cross-sectional view of this utility model.

[0013] Figure 3 This is a schematic diagram of the assembly structure of this utility model.

[0014] Figure 4 This is an assembly cross-sectional view of the present invention.

[0015] In the diagram: 1. Negative pressure chamber, 2. Lower molding sand box, 3. Upper molding sand box, 4. Sealing strip, 5. Filter screen, 6. Air extraction pipe, 7. Upper sealing groove, 8. Lower sealing groove, 9. Molding sand. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0017] like Figures 1-4 The large sand casting rapid cooling sand box device shown includes an upper sand box 3 and a lower sand box 2, both with rectangular cross sections and the same external dimensions. Molding sand 9 is placed in the inner cavity of both the lower sand box 2 and the upper sand box 3. A lower sealing groove 8 is opened on the parting surface at the upper end of the lower sand box 2, and an upper sealing groove 7 is opened on the parting surface at the lower end of the upper sand box 3. The sealing strip 4 used for sealing the box is located in the space enclosed by the lower sealing groove 8 and the upper sealing groove 7.

[0018] The bottom surface of the lower molding sand box 2 is provided with a negative pressure chamber 1 with a rectangular cross-section. The negative pressure chamber 1 is a closed chamber on all sides and bottom surface. A rectangular opening is opened on the top surface of the negative pressure chamber 1. The bottom surface of the lower molding sand box 2 communicates with the rectangular opening on the top surface of the negative pressure chamber 1. A rectangular filter screen 5 is installed on the rectangular opening. The filter screen 5 can play a role in air permeability, and the mesh size of the filter screen 5 is larger than the particle size of the molding sand 9 to prevent the molding sand 9 in the lower molding sand box 2 from entering the negative pressure chamber 1. An air extraction pipe 6 is connected to the outer side of the negative pressure chamber 1.

[0019] The bottom dimension of the lower molding sand box 2 is larger than the size of the filter screen 5, so as to ensure that all the air contained in the molding sand 9 in the lower molding sand box 2 and the upper molding sand box 3 can pass through the filter screen 5 and enter the negative pressure chamber 1.

[0020] When closing the boxes, place the lower sand box 2 with the sand mold prepared flat on the upper part of the negative pressure chamber 1. The perimeter of the lower sand box 2 completely covers the filter screen 5 at the top of the negative pressure chamber 1. Place the sealing strip 4 on the lower sealing groove 8 at the parting surface of the lower sand box 2. Place the upper sand box 3 with the sand mold prepared facing down on the lower sand box 2. Ensure that the upper sealing groove 7 at the horizontal surface of the upper sand box 3 is fully engaged with the sealing strip 4, thereby achieving an air seal and completing the box closing operation.

[0021] During the pouring and cooling of molten iron, air is evacuated from the negative pressure chamber 1 through the evacuation pipe 6, creating a negative pressure within the chamber. This accelerates the removal of air from the molding sand 9 in the lower and upper molding sand boxes 2 and 3, improving heat exchange during the molten metal flow, and speeding up the filling and cooling of the molten iron. Consequently, the casting unpacking time is shortened, increasing production efficiency. Simultaneously, the polluting and harmful gases generated after the binder in the molding sand 9 decomposes upon heating are collected and purified, significantly reducing the harmful gases produced during sand casting and contributing to environmental protection.

[0022] The sand box device effectively controls the sequential solidification of different parts of the casting by controlling the direction, pressure, and airflow rate of the negative pressure. It also achieves rapid cooling of the molten metal. The purpose is to improve the fluidity of the molten metal, accelerate the evacuation of air from the molding sand, and promote the formation of more crystal nuclei and refine the grains by changing the solidification sequence and flow rate of the molten metal. This reduces casting defects such as porosity, sand adhesion, shrinkage cavities, and shrinkage porosity that are prone to occur during the solidification process, thereby improving the internal quality of the casting.

[0023] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A rapid cooling sand box device for large sand castings, comprising a lower sand box (2) and an upper sand box (3) sealed and enclosed on the lower sand box (2), wherein molding sand (9) is placed in the inner cavity of both the lower sand box (2) and the upper sand box (3), characterized in that: The bottom surface of the lower sand box (2) is provided with a negative pressure chamber (1), and a rectangular filter screen (5) is installed on the top surface of the negative pressure chamber (1). An air extraction pipe (6) is connected to the outer side of the negative pressure chamber (1) to form a negative pressure inside the negative pressure chamber (1).

2. The rapid cooling sand box device for sand castings as described in claim 1, characterized in that: The lower sand box (2) has a lower sealing groove (8) on the parting surface at the upper end, and the upper sand box (3) has an upper sealing groove (7) on the parting surface at the lower end. The sealing strip (4) used for sealing the box is located in the space enclosed by the lower sealing groove (8) and the upper sealing groove (7).

3. The rapid cooling sand box device for sand castings as described in claim 1, characterized in that: The cross-sections of the lower sand box (2), the upper sand box (3), and the negative pressure chamber (1) are all rectangular.

4. The rapid cooling sand box device for sand castings as described in claim 3, characterized in that: The bottom dimension of the lower sand box (2) is larger than the dimension of the filter screen (5).

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