Core sand cooling device and core sand cooling system

Abstract

To provide a cooling device and a cooling system for core sand capable of recovering core sand without requiring a dust collector.SOLUTION: A cooling system 1 for core sand includes a cooling device 10 and a blower 20 disposed outside the cooling device 10 and blowing air to the cooling device 10. The cooling device 10 includes a cooling member 13 arranged at a predetermined angle with respect to the horizontal direction in a housing of the cooling device 10, and is a core sand using water glass as a binder to cool the core sand flowed from above. The cooling member 13 has an internal region 11 located in the internal space of the housing and an external region 12 projecting outside the housing.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a core sand cooling device and a core sand cooling system. [Background technology]

[0002] Patent Document 1 describes a technique for recovering core sand by blowing air onto the core sand that uses water glass as a binder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-015813 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology described in Patent Document 1, sand and air are mixed together and suspended in the air, so a dust collector may be required.

[0005] An object of the present invention is to provide a core sand cooling system capable of recovering core sand without requiring a dust collector. [Means for solving the problem]

[0006] In order to achieve the above object, one aspect of the present invention provides a core sand cooling device that is disposed in a housing of the cooling device at a predetermined angle to the horizontal and includes a cooling member that cools the core sand that uses water glass as a binder and is poured in from above, the cooling member having an internal region located in the internal space of the housing and an external region that protrudes outside the housing. According to this aspect, the cooling is performed by heat exchange via the cooling member, and since the core sand and air are not directly mixed, it is possible to prevent the core sand from flying around and there is no need to use a dust collector.

[0007] The cooling member may be a heat pipe, which can increase the heat exchange efficiency and improve the cooling effect.

[0008] The cooling device can also be configured to include a distribution plate that distributes the core sand that is dropped onto the upper surface of the cooling member, thereby allowing the core sand to flow in a dispersed manner rather than in a straight line on the cooling member, thereby improving the cooling effect.

[0009] The cooling member may be configured to be arranged in the housing as a pipe set having a plurality of cooling pipes arranged in parallel, thereby improving the cooling efficiency relative to the installation area of ​​the cooling device.

[0010] Furthermore, a plurality of the pipe sets can be arranged in the housing so that the flow path of the core sand when viewed from the horizontal direction is bellows-shaped. This allows the flow path for cooling the core sand to be longer relative to the installation area of ​​the cooling device, thereby improving the cooling effect relative to the installation area of ​​the cooling device.

[0011] A core sand cooling system according to another aspect of the present invention includes the cooling device and an air blower disposed outside the cooling device for blowing air to the cooling device, thereby improving the cooling effect of the core sand. Effect of the Invention

[0012] According to the present invention, it is possible to provide a core sand cooling device and a core sand cooling system that are capable of recovering core sand without the need for a dust collector. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a schematic diagram showing one configuration example of a cooling system for core sand according to an embodiment. [Diagram 2]2 is a perspective view showing an example of a pipe set provided in a cooling device in the cooling system of FIG. 1. [Diagram 3] 2 is a top view showing an example of a dispersion plate provided in the cooling device in the cooling system of FIG. 1. [Figure 4] FIG. 2 is a flow diagram for explaining an example of a method for reusing core sand using the cooling system of FIG. [Diagram 5] FIG. 2 is a graph showing a test example using the cooling system of FIG. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will be described below through embodiments of the invention, but the invention according to the claims is not limited to the following embodiments. Also, not all of the configurations described in the embodiments are necessarily essential as means for solving the problems. The embodiments will be described below with reference to the drawings.

[0015] <Embodiment Mode> FIG. 1 is a schematic diagram showing an example of the configuration of a core sand cooling system according to the present embodiment.

[0016] As shown in FIG. 1, a core sand cooling system 1 according to this embodiment includes a cooling device 10 and an air blower 20 that is disposed outside the cooling device 10 and blows air to the cooling device 10.

[0017] The cooling device 10 includes one or more cooling members 13. The cooling members 13 are disposed at a predetermined angle to the horizontal direction in the housing of the cooling device 10, and cool the core sand SA (core sand for casting) that uses water glass as a binder and that is poured from above.

[0018] Each cooling member 13 has an internal region 11 located in the internal space of the housing (that is, protruding inward), and an external region 12 protruding to the outside of the housing.

[0019] Furthermore, by setting the above-mentioned predetermined angle to be equal to or greater than the repose angle of the core sand SA to be cooled, it is possible to perform cooling while preventing the core sand from becoming stuck during cooling. Furthermore, the above-mentioned predetermined angle can be varied depending on the installation position of the cooling member 13 in the cooling device 10, for example, the lower the cooling member 13 is installed, the larger the angle can be. In particular, by changing such a predetermined angle depending on the vertical position, that is, by using a predetermined angle that is adapted to a repose angle depending on the level of cooling, it is possible to maintain the same flow regardless of the level of cooling.

[0020] The core sand to be cooled (core sand before cooling) SA is loaded from an inlet 14 located, for example, at the top of the cooling device 10, cooled along the way, and can be collected as cooled core sand SC in a collection mechanism such as a collection container 15 located near the bottom of the cooling device 10. Furthermore, the composition of the core sand SA to be cooled in the cooling system 1 does not matter as long as it is core sand made of water glass. However, since the angle of repose differs depending on the composition of the core sand SA to be cooled, it is advisable to vary the above-mentioned predetermined angle depending on the composition of the core sand SA to be cooled.

[0021] The blower 20 may be a fan or blower that blows cooling air, and the temperature of the blown air may be suitable for cooling. The blower 20 may blow air toward the external area 12. However, the blower 20 may be provided in a position where the air from the blower 20 hits the external area 12 directly, or may be provided in a position where the air hits the external area 12 indirectly. As shown by the solid white arrow in FIG. 1, the air from the blower 20 may hit the external area 12 directly or indirectly, and the air may escape as shown by the dotted white arrow in FIG. 1.

[0022] The cooling device 10 according to this embodiment has a configuration in which cooling is performed by heat exchange via the cooling member 13, and does not directly mix the core sand SB with the air during cooling, so that the core sand SB can be prevented from flying around and there is no need to use a dust collector. In addition, by using the cooling system 1 also equipped with the air blower 20, the cooling effect of the core sand can be improved.

[0023] In a configuration in which a plurality of cooling members 13 are provided, they can be arranged, for example, as follows, as shown in the schematic diagram of the inside of the cooling device 10 viewed from one side in Fig. 1. That is, for example, the cooling device 10 can be provided with its outer region 12 protruding from one side, and another cooling member 13 can be provided with its outer region 12 protruding from the side opposite to the first side.

[0024] 1, the inside of cooling device 10 is seen from only one side, but on the side perpendicular to that side, cooling member 13 can be arranged so that the inside of the housing of cooling device 10 comes into contact with cooling member 13. This makes it possible to prevent core sand SA, SB from falling without coming into contact with cooling member 13.

[0025] 1 is a schematic diagram showing the inside of the cooling device 10 viewed from one side, a plurality of cooling members 13 can be arranged in the housing so that the flow path for cooling the core sand SB viewed from the horizontal direction becomes bellows-shaped. This allows the flow path for cooling the core sand to be longer relative to the installation area of ​​the cooling device 10, thereby improving the cooling effect relative to the installation area of ​​the cooling device 10.

[0026] Also, the cooling member 13 can be a pipe-shaped cooling pipe having a hollow portion, which can increase the surface area in contact with the core sand SB and improve the cooling effect. However, the cooling member 13 is not limited to a cooling pipe, and a certain level of cooling effect can be obtained even if it is a rod-shaped or flat plate-shaped member that does not have a cavity. In particular, this cooling pipe can be a heat pipe. Below, an example will be described in which the cooling member 13 is a heat pipe 13, which is an example of a cooling pipe.

[0027] The heat pipe 13 may be, for example, a metal pipe made of iron or copper, using water as the working fluid, but the material and working fluid are not limited to these. The cross-sectional shape of the heat pipe 13 is also not limited. The heat pipe 13 dissipates heat to the outside of the cooling device 10 at a heat transfer rate equal to or faster than the material (metal, etc.). In other words, by using the heat pipe 13, the heat of the core sand SB can be transferred to the outside of the equipment and efficiently dissipated by the ambient temperature, and in particular, by providing the air blower 20, the heat can be efficiently dissipated by the cooling air. In this way, by using the heat pipe 13, it is possible to increase the heat exchange efficiency and improve the cooling effect. However, a certain level of cooling effect can be obtained even if the cooling pipe is not a heat pipe.

[0028] Next, an example of the arrangement of the heat pipes 13 will be described with reference to Fig. 2. Fig. 2 is a perspective view showing an example of a pipe set 13S provided in the cooling device 10 in the cooling system 1 of Fig. 1. Note that the following example of the arrangement can be similarly applied to cooling members other than heat pipes.

[0029] As shown in Figs. 1 and 2, the heat pipe 13 can be configured to be arranged in the housing of the cooling device 10 as a pipe set 13S, which is configured by arranging four heat pipes 13a to 13d in parallel. A working fluid HF is stored inside each of the heat pipes 13a to 13d. The working fluid HF can be, for example, water or naphthalene. The working fluid HF is heated by the heat from the outer surface corresponding to the inner region 11 and vaporized, and is cooled and liquefied by the outer surface corresponding to the outer region 12 and returns to the inner region 11 side. Therefore, when a heat pipe is used as the cooling member 13, the predetermined angle can be set to an angle such that the outer region 12 is higher than the inner region 11, as exemplified in Fig. 1.

[0030] Of course, the number of heat pipes arranged in parallel is not limited to four, and may be two or more. In particular, the four or more heat pipes 13a-13d included in the pipe set 13S can be connected to each other between adjacent heat pipes (for example, between the heat pipes 13a and 13b). This not only prevents the core sand SB from falling through the gaps between the heat pipes, reducing the cooling effect, but also spreads the area that can be cooled, improving the cooling efficiency relative to the installation area of ​​the cooling device 10.

[0031] The flow path for the core sand SB shown in FIG. 1 can also be formed by arranging multiple cooling elements having flat cross sections in a bellows-like shape. However, compared to this type of flow path formation, the flow path formed using the pipe set 13S has a greater number of pipes capable of heat exchange, and therefore has a greater cooling effect.

[0032] In addition, the cooling device 10 can be provided with a distribution plate 16 at a position between the core sand SA's feed port 14 and the first pipe set 13S, as illustrated in Fig. 1. An example of the distribution plate 16 will be described with reference to Fig. 3. Fig. 3 is a top view showing an example of the distribution plate 16 provided in the cooling device 10 in the cooling system 1 of Fig. 1.

[0033] The distribution plate 16 is a plate for dispersing the core sand dropped onto the upper surface of the pipe set 13S (or a cooling member 13 having another configuration), and can be made of, for example, a punched metal or a mesh. The distribution plate 16 is provided with a plurality of holes 16a having a diameter larger than that of the core sand SA. When the distribution plate 16 is made of a mesh, the holes 16a correspond to the mesh.

[0034] Here, the core sand SA has a diameter of, for example, 50 to 300 μm (average 150 μm), but the shape of the distribution plate 16 is not important as long as it allows the core sand SA to fall smoothly in a dispersed manner. In other words, as long as such dispersion and fall is possible, the diameter and shape of the holes 16a in the distribution plate 16 and the pitch between the holes 16a are not important, and although a staggered arrangement is given as an example of the arrangement of the holes 16a, the arrangement method and angle of the arrangement are also not important, and the proportion of the open areas of the distribution plate 16 to the total area (opening rate) is also not important.

[0035] By providing the distribution plate 16, the core sand SA, which is untreated (uncooled) sand, can be uniformly distributed within the cooling device 10 and can come into efficient contact with the exhaust air. In other words, by providing the distribution plate 16, the core sand SA can be uniformly distributed and made to fall and flow within the cooling device 10, rather than in a straight line, improving the contact efficiency with the heat pipes 13a to 13d, increasing the heat exchange efficiency, and improving the cooling effect.

[0036] Next, a method for reusing core sand using the cooling system 1 will be illustrated with reference to Fig. 4. Fig. 4 is a flow diagram for illustrating an example of a method for reusing core sand using the cooling system 1 of Fig. 1.

[0037] As shown by the steps within the dotted line in Fig. 4, the method for recycling core sand according to this embodiment can include a crushing step (step S1), a heating step (step S2), a cooling step (step S3), which is a characteristic part of this embodiment, a peeling step (step S4), and a separation and recovery step (step S5). In the crushing step shown in step S1, the cores used in casting are crushed until they become granular. In this recycling method, defective cores SD that cannot be used for casting (step S7) because of chipping or cracking of the cores when reused for core molding (step S6) are also crushed in the crushing step (step S1). Note that the steps other than step S3 are not important and detailed description thereof will be omitted, but corresponding steps described in Patent Document 1, for example, can be adopted.

[0038] In the heating step shown in step S2, the granules are heated at a temperature of, for example, 300°C to 550°C, and the amount of water-soluble water glass in the water glass 15 contained in the granules is made smaller than the amount of water-insoluble water glass. This makes it possible to prevent the hardening of the core sand from being hindered when it is reused.

[0039] After heating, in the cooling process shown in step S3, granular core sand SA is fed into the inlet 14 of the cooling system 1, and heat exchange takes place inside the cooling device 10 via the heat pipe 13, cooling the core sand to below the polishing processing temperature, resulting in cooled core sand SC.

[0040] Next, in the peeling process shown in step S4, the cooled granules are collided with each other to peel the water glass from the core sand SC. In the separation and recovery process shown in step S5, air is blown onto the mixture of the peeled water glass and core sand, and the core sand is separated and recovered from the mixture due to the difference in specific gravity between the water glass and the core sand.

[0041] In this way, used core sand can be reused for core molding (step S6) by processing it in the order of crushing step (step S1), heating step (step S2), cooling step (step S3), peeling step (step S4), and separation and recovery step (step S5). In core molding, core sand is placed in a mold and heated to harden it to form a core. The heating temperature is, for example, lower than that for casting. This allows it to be reused so that it has the same core strength as new sand.

[0042] Next, as shown in step S7, the molded core is used for casting. The casting is, for example, aluminum casting at a molten metal temperature of 650°C to 750°C. Next, as shown in step S8, post-processing is performed. In the post-processing, the used core is shaken off from the casting formed by casting. Then, in order to reuse the core sand, a crushing process in step S1 is performed. By adopting such a recycling method, it is possible to reuse even cores that use water glass as a binder, thereby reducing manufacturing costs.

[0043] Next, the effects of the cooling device 10 and the cooling system 1 according to the present embodiment will be described in detail with reference to test examples.

[0044] When general casting sand is reused, it is heated by a gas burner, etc., and then cooled by water spraying and air flow before being used as reused sand. However, water glass binder cannot be completely removed by heating, so if water is sprayed, the adhesive power of the binder is restored. For this reason, water is prohibited when cooling recycled sand for inorganic cores because the water glass binder remains. To cool heated sand, a method of heat exchange using air flow is usually adopted, but the sand and air are mixed, so dust is generated and a dust collector is required. Furthermore, problems such as dust accumulating in the dust collector duct occur, so regular cleaning is required. Specifically, when air is used, the dust collection duct becomes clogged, reducing the cooling capacity, and there is a risk of the sand rising and falling into the duct. For example, casting sand contains about 20% sand under 100μm and about 1% water glass fine powder (50μm or less), and this powder gets stirred up by the flowing air and accumulates in the duct. Also, when air is used, the water glass fine powder absorbs moisture from the air and becomes sticky, causing it to stick to the inside of the duct. For these reasons, when air is used, a dust collector is required, and the dust collector must be cleaned regularly.

[0045] In contrast, in the cooling device 10 and cooling system 1 of the present embodiment, the core sand SA is cooled without intentionally bringing the core sand SA into direct contact with the air in order to promote heat exchange with the air, thereby eliminating the need for a dust collector and the need to clean it.

[0046] A specific cooling effect will be described with reference to Fig. 5. Fig. 5 is a graph showing a test example using the cooling system 1 of Fig. 1.

[0047] Here, in the cooling system 1 of Fig. 1, the pipe set 13S in which the heat pipes are arranged is set at a predetermined angle of 45°, and alumina-based artificial sand (a mixture of AC Alumina Sand (registered trademark) manufactured by Hyohya Co., Ltd. and green beads manufactured by San-ei Silica Co., Ltd.) heated to 400°C is fed as the core sand SA at 80 kg / h to conduct the test. In this test, a heat pipe with an iron container and water as the working fluid is used as the heat pipe, and the air blower 20 blows 10 m from the outside of the cooling device 10. 3 The outside temperature during this test was approximately 30°C.

[0048] The results of this test are shown in Figure 5. As shown in Figure 5, core sand SA heated to 400°C was charged from charging port 14, and heat was exchanged by blowing air around the outer periphery of cooling device 10 with air blower 20, and it was discharged as core sand SC cooled to about 150°C. From these test results, it can be said that a sufficient cooling effect can be obtained in this embodiment. In Figure 5, the exhaust temperature refers to the temperature of the air blown from air blower 20 downstream of cooling device 10. In Figure 5, the period from 0 to 5 minutes is the lag from when core sand SA is charged until the temperature sensor can normally measure the temperature of the core sand at its installation position.

[0049] (Alternative example) The cooling system according to the above-described embodiment is not limited to the exemplified shapes and structures, and may be any as long as the functions of each component are fulfilled.

[0050] For example, the shape, configuration, and function of devices other than the cooling device and the air blower included in the core sand recovery device are not important. Air blowers 20 may be provided in multiple locations. Although the cooling system 1 has been described on the assumption that it includes air blowers 20 for the cooling member, a certain degree of cooling effect can be achieved even if the air blower 20 is not provided.

[0051] The cooling member does not have to be arranged as a pipe set, and may be arranged as one pipe per location. In that case, the cooling member should be configured to have a flat cross-sectional shape so that a large area of ​​the cooling member can come into contact with the core sand SB.

[0052] Furthermore, the cooling device and cooling system according to the embodiment can be suitably used for core sand that uses a water glass binder, but can be used for any type of core sand.

[0053] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0054] 1 Cooling system 10 Cooling device 11 Internal area 12 External area 13 Cooling components (cooling pipes, heat pipes) 13a, 13b, 13c, 13d Heat pipes 13S Pipe Set 14 Inlet 15 Collection container 16 Dispersion plate 16a hole 20 Blower HF Hydraulic Fluid SA Core sand before cooling SB Core sand during cooling SC Core sand after cooling SD defective core

Claims

1. A core sand cooling device comprising: a cooling member disposed in a housing of the cooling device at a predetermined angle to a horizontal direction and configured to cool the core sand using water glass as a binder and poured from above; The cooling member has an internal region located in the internal space of the housing and an external region protruding to the outside of the housing. Cooling device for core sand.

2. The cooling member is a heat pipe.

2. The core sand cooling device according to claim 1.

3. a distribution plate for dispersing the core sand that is dropped onto the upper surface of the cooling member; 3. The cooling device for core sand according to claim 1 or 2.

4. The cooling member is arranged in the housing as a pipe set having a plurality of cooling pipes arranged in parallel. The core sand cooling device according to any one of claims 1 to 3.

5. a plurality of the pipe sets are arranged in the housing so that a flow path of the core sand when viewed from a horizontal direction is bellows-shaped; 5. The core sand cooling device according to claim 4.

6. 6. A cooling system for core sand comprising: the cooling device according to claim 1; and an air blower arranged outside the cooling device and blowing air to the cooling device.

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