Precision casting slurry stirring device

Abstract

The present invention aims to provide a stirring device for precision casting, and more specifically, to provide a slurry stirring device for precision casting that generates a vertical circulation flow by rotating a tank, thereby preventing slurry sedimentation and extending the service life of each conventional device. [Solution] The present invention relates to a slurry stirring device for precision casting, which stirs a slurry that is a solid-liquid two-phase fluid consisting of a liquid phase and powdered particles. The device comprises a base, an arm fixed to the base, a rotary drive unit, a tank rotated by the rotary drive unit, a stirring blade fixed to the arm and positioned at the bottom of the tank, and a vertical shielding plate fixed to the arm and positioned at the side of the tank. The device employs a configuration that generates not only circumferential circulation flow but also vertical circulation flow to prevent slurry sedimentation.

Description

Technical Field

[0001] The present invention relates to a stirring device in precision casting. Specifically, in the stirring of viscous substances, a baffle plate is fixed to a base, and the stirring tank is rotated to increase the relative speed between the stirring blades and the liquid, generating turbulent flow and creating a circulating flow in the circumferential and vertical directions, thereby obtaining a good diffusion effect without stagnant areas. The present invention relates to the technology of a stirring device.

Background Art

[0002] As a casting method for precision castings, there is the "lost wax method". The feature of such a casting method is that it can manufacture products made of materials that are particularly difficult to machine and have complex shapes with high dimensional accuracy. In recent years, with the spotlight on the global warming issue, in order to improve the thermal efficiency of gas turbine combined cycle power generation, which is attracting attention worldwide as an effective countermeasure, this lost wax method is an essential technology for manufacturing turbine blades with excellent heat resistance required for this purpose.

[0003] In particular, in order to cool the turbine blade so that it can withstand the gas turbine inlet temperature of 1,650 °C, an advanced technology for creating cavities (holes) through which air or steam flows inside the blade is essential. At the same time, in precision casting by the lost wax method, the uniform mixing of the slurry greatly affects the quality of the final product. Therefore, it can be said that the slurry stirring device plays an important role in precision casting by the lost wax method.

[0004] The roles of a slurry agitator include uniform particle dispersion, bubble removal, and viscosity adjustment. Uniform particle dispersion ensures even distribution of ceramic particles and binders in the slurry, improving strength and dimensional accuracy during mold creation. Bubble removal effectively eliminates bubbles generated during mixing, reducing voids in the mold and increasing product density. Agitation adjusts the viscosity of the slurry, optimizing mold filling and surface finish. Furthermore, agitators significantly impact product quality, productivity, and cost reduction. Specifically, a uniform slurry ensures uniform mold shrinkage and improves product dimensional accuracy, while a slurry with fewer bubbles creates a smoother mold surface and improves product surface finish. Moreover, uniform particle dispersion improves mold strength and prevents product breakage.

[0005] Conventional agitators use rotating agitators to generate circulating flow in a suspension of dispersed fine solid particles. However, if the agitator's position is not moved vertically, layered stagnation occurs, preventing uniform agitation. Furthermore, when the suspension is viscous, a large torque is required to rotate the agitator, which can easily damage it. In addition, in precision casting methods such as the lost-wax method, it is difficult to install agitator blades in the tank because the part model is immersed in a slurry in the tank to manufacture the model that serves as the prototype for the casting. For this reason, commonly used tank structures involve rotating the agitator blades within a fixed tank, or placing flat baffles within a rotating tank, or rotating such baffles within a fixed tank. However, in all of these configurations, turbulence is generated, creating circulating flow not only in the circumferential direction but also vertically, resulting in problems such as the inability to achieve good diffusion without stagnation, and the occurrence of stagnation.

[0006] In light of this situation, various technical proposals have been made in the past. One invention is titled "Slurry Storage Tank," and the problem it aims to solve is "to provide a storage tank for slurry used in coating perishable models in investment storage methods." The solution is described as "a fixed-position tank body with an open top, a baffle plate positioned near the outer periphery of the tank body with its surface facing the direction of movement, and a driving means for moving the baffle plate along the inner wall surface of the tank body." However, this technology employs a driving means to move the baffle plate along the inner wall surface of the tank body, which does not solve the problem of the baffle plate being subjected to a large load and easily damaged. It can be said that this technology differs from the present invention in that it does not employ a driving means that rotates the tank body to solve the problem.

[0007] Furthermore, the invention is titled "Slurry Agitation Device," and the problem it aims to solve is "to provide a slurry agitation device that can efficiently utilize the fast flow generated near the inner wall of the tank to create a vertical circulation flow, thereby preventing slurry sedimentation and improving performance." The specific solution is described as "inserting and arranging an agitation means into the tank to generate a vertical circulation flow from the circumferential flow of slurry generated as the tank rotates, and configuring the agitation means as an L-shaped agitation member consisting of a hollow vertical agitation blade and a hollow horizontal agitation blade" (Patent Document 2). The technology described in Patent Document 2 and the present invention are similar in that the tank rotates and the vertical agitation part is fixed. However, in the technology described in Patent Document 2, the vertical agitation blade and the horizontal agitation blade are made of an integrated L-shaped member, and the horizontal agitation blade is also fixed to the rotating tank, whereas in the present invention, the agitation blades provided horizontally along with the tank rotate, and the load on these blades and the means for guiding the horizontal flow are different.

[0008] Furthermore, the invention is titled "Agitation Device for Mixed Matter," and the problem to be solved is "to prevent the accumulation of mixed matter and to promote turbulence." The specific solution is described as follows: "When the round can rotates, for a predetermined time, the stirring blades are in contact with the inner surface of the round can, so the movement of the mixed matter is prevented and it is stirred toward the center of the can. After a predetermined time has elapsed, the stirring blades move away from the inner surface, so the mixed matter in the accumulated areas before and after the stirring blades separates from the stirring blades. Next, the moving stirring blades become an obstacle to the mixed matter adhering to the inner surface of the can, and this stirring is effectively repeated." This technology is similar to the present invention in that a round can, which is the container for the mixed matter, rotates and is stirred by fixed stirring blades. However, the technology described in Patent Document 3 involves moving the position of the stirring blades at predetermined time intervals, so the technical means for solving the problem are different. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Utility Model Publication No. 61-63339 [Patent Document 2] Japanese Patent Publication No. 2005-270758 [Patent Document 3] Japanese Patent Application Publication No. 7-171369 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The present invention aims to provide a stirring device for precision casting, and more specifically, to provide a slurry stirring device that can extend the service life of conventional devices by generating a vertical circulating flow by rotating a tank, thereby preventing slurry sedimentation. More specifically, the invention aims to provide a stirring device that, in stirring viscous materials, fixes a baffle plate to a base and rotates the stirring tank to increase the relative velocity between the stirring blades and the liquid, thereby creating a circulating flow in the circumferential and vertical directions while generating turbulence, and achieving a good diffusion effect without stagnation. [Means for solving the problem]

[0011] The present invention relates to a slurry stirring device for precision casting, for stirring a slurry which is a solid-liquid two-phase fluid consisting of a liquid phase and powdered particles. The device comprises a base, an arm fixed to the base, a rotary drive unit, a tank rotated by the rotary drive unit, a stirring blade fixed to the bottom of the tank, and a vertical shielding plate fixed to the arm and positioned on the side of the tank. The stirring blade is formed to always ensure a predetermined scoop angle with respect to the tangential direction of the inner circumferential surface of the tank and the bottom surface, and employs a configuration that generates not only a circumferential circulation flow but also a vertical circulation flow to prevent the slurry from settling.

[0012] Furthermore, the present invention may also employ a configuration in which a plurality of the vertical shielding plates are provided.

[0013] Furthermore, the present invention may also employ a configuration in which vertical flow guide vanes are provided on the vertical shielding plate.

[0014] Furthermore, the present invention may also employ a configuration in which the inclination angle of the vertical flow guide vanes provided on the vertical shielding plate is within the range of 40 to 50 degrees. [Effects of the Invention]

[0015] In conventional systems where a stirring blade rotates in a fixed tank, only circulating flow occurs in the circumferential direction. However, the precision casting stirring device according to the present invention can generate circulating flow in the vertical direction, exhibiting the excellent effect of significantly improving the sedimentation of refractory materials constituting the slurry at the bottom of the tank.

[0016] Furthermore, the precision casting stirring device according to the present invention generates not only circulating flow in the circulating direction but also circulating flow in the vertical direction, resulting in sufficient stirring inside the tank and extending the period during which the slurry can be used, thus exhibiting excellent effects.

[0017] Further, according to the stirring device for precision casting according to the present invention, since the stirring blades do not rotate and the tank rotates, the stirring blades are not driven in the viscous slurry, so the load on the stirring blades is small and it is difficult to be damaged, exhibiting an excellent effect of high durability.

[0018] Also, in the slurry stirring device for precision casting according to the present invention, when adopting a configuration including a plurality of vertical shielding plates, a vertical circulation flow occurs for each of the arranged vertical shielding plates in the vertical direction, so the inside of the tank is sufficiently stirred, and an excellent effect of being able to obtain a homogeneous slurry is exhibited.

[0019] Also, in the slurry stirring device for precision casting according to the present invention, when adopting a configuration in which vertical flow guiding blades are provided on the vertical shielding plates, a larger vertical circulation flow occurs for each of the arranged vertical shielding plates in the vertical direction, so the inside of the tank is sufficiently stirred, and an excellent effect of being able to obtain a more homogeneous slurry is exhibited.

[0020] Also, in the slurry stirring device for precision casting according to the present invention, when adopting a configuration in which the inclination angle of the vertical flow guiding blades provided on the vertical shielding plates is within the range of 40 degrees to 50 degrees, a larger vertical circulation flow occurs for each of the arranged vertical shielding plates in the vertical direction, so the inside of the tank is sufficiently stirred, and an excellent effect of being able to obtain a more homogeneous slurry is exhibited.

Brief Description of the Drawings

[0021] [Figure 1] It is a perspective view of basic configuration explanation for explaining the basic configuration of the slurry stirring device for precision casting according to the present invention. [Figure 2] It is a plan view of basic configuration explanation for explaining the basic configuration of the slurry stirring device for precision casting according to the present invention. [Figure 3] It is a sectional view of explanation for explaining the arrangement configuration of the stirring blades and the vertical shielding plates in the slurry stirring device for precision casting according to the present invention. [Figure 4]It is a stirring state explanatory diagram for explaining the stirring state of slurry in the slurry stirring device for precision casting according to the present invention. [Figure 5] It is a vertical shielding plate explanatory diagram for explaining the vertical shielding plate and the vertical shielding plate with vertical flow guide vanes attached to the vertical shielding plate in the slurry stirring device for precision casting according to the present invention. [Figure 6] It is an experimental state explanatory diagram showing the experimental state of the slurry stirring device for precision casting according to the present invention. [Figure 7] It is an experimental device configuration explanatory diagram showing the configuration of the experimental device used in the experiment of the present invention.

Embodiments for Carrying out the Invention

[0022] The slurry stirring device for precision casting according to the present invention comprises a base, an arm portion fixed to the base, a rotational drive portion, a tank rotated by the rotational drive portion, stirring blades fixedly arranged at the bottom within the tank, and a vertical shielding plate fixed to the arm portion and arranged at the side within the tank. The stirring blades are formed to always ensure a predetermined scooping angle with respect to the tangential direction of the inner peripheral surface of the tank and the bottom surface, generating not only a circumferential circulation flow but also a vertical circulation flow to prevent precipitation of the slurry, which is the greatest feature. Hereinafter, it will be described based on the drawings. However, it is not limited to the shapes and configurations shown in such drawings, and can be changed within the range where the effects of the creative technical idea of the present invention can be obtained.

[0023] FIG. 1 is a basic configuration explanatory perspective view for explaining the basic configuration of the slurry stirring device for precision casting according to the present invention.

[0024] FIG. 2 is a basic configuration explanatory plan view for explaining the basic configuration of the slurry stirring device for precision casting according to the present invention. FIG. 2(a) shows a plan view in a state seen from above, and FIG. 2(b) shows a front view in a state seen from the horizontal direction.

[0025] The precision casting slurry stirring device 1 is a stirring device for stirring a slurry S, which is a solid-liquid two-phase fluid consisting of a liquid phase and powdered particles. It consists of a base 10, an arm 20 fixed to the base 10, a rotary drive unit 30, a tank 40 rotated by the rotary drive unit 30, a stirring blade 50 fixed to the bottom of the tank 40, and a vertical shielding plate 60 fixed to the arm 20 and positioned on the side of the tank 40. The stirring blade 50 is formed to always ensure a predetermined scoop angle 51 with respect to the tangential direction of the inner circumferential surface 42 of the tank 40 and the bottom surface 43. The basic configuration is to generate not only a circumferential circulating flow E but also a vertical circulating flow J to prevent the slurry S from settling. The following points should be considered when selecting a stirring device. It is necessary to select a stirring device that matches the characteristics of the slurry S, namely viscosity, particle size, and solid content concentration; to select a device that matches the desired stirring effect, such as homogenization, defoaming, and viscosity adjustment; and to select a device with appropriate processing capacity according to the production volume. Therefore, slurry stirring devices in precision casting are important devices that greatly contribute to improving product quality, increasing productivity, and reducing costs. By selecting an appropriate stirring device according to the characteristics of the slurry and manufacturing conditions, and by setting optimal stirring conditions, it is possible to stably manufacture high-quality products. The following describes each component.

[0026] A slurry S is a suspension or solid-liquid mixture in which fine solid particles are dispersed and suspended throughout a liquid; it is also called a mud. The viscosity coefficient tends to change depending on the proportion of fine solid particles. As the solid concentration increases, it often changes from a Newtonian fluid to a non-Newtonian fluid, and depending on how the viscosity coefficient changes, it can become Bingham fluid-like or, conversely, dilatant.

[0027] The base 10 is a base portion that holds the tank 40, which is rotated by a rotation drive unit 30. The base 10 is also provided with an arm portion 20 for fixing the vertical shielding plate 60 to the rotationally driven tank 40.

[0028] The arm portion 20 is fixed to the base 10 and is equipped with a vertical shielding plate 60 that is fixed against the rotation of the tank 40.

[0029] The rotary drive unit 30 is a device for rotating the tank 40 and is equipped with a motor M, a power supply unit, and an inverter control board I for rotational speed control on the base 10. It is desirable that the rotary drive unit 30 be covered with a housing or waterproof plate as shown in the drawing to prevent electrical leakage.

[0030] Tank 40 is a container for stirring the slurry S and is rotationally driven by the rotary drive unit 30.

[0031] The stirring blade 50 is fixed to the tank 40 and generates a circumferential circulating flow E in the slurry S. The drawings are merely examples, and the shape and number of blades are not particularly limited; the present invention includes configurations that exhibit similar effects.

[0032] The scoop angle 51 is the angle at which each blade of the stirring blade 50 rises relative to the horizontal direction. By providing this scoop angle, it becomes possible to smoothly stir even highly viscous slurry S without forming a stagnant area T above the stirring blade 50, and it also facilitates the creation of a vertical circulating flow J.

[0033] The vertical shielding plate 60 is a so-called baffle plate fixed to the arm portion 20 which is fixed to the base, and generates a vertical circulating flow J in the slurry S. The vertical shielding plate 60 shown in Figure 1 is an embodiment in which vertical flow guide vanes 70 are attached, and it is desirable to provide such vertical flow guide vanes 70.

[0034] The circumferential circulation flow E, as shown in Figures 4(a) and (b), indicates the direction in which the slurry S flows within the tank 40 and represents the circumferential flow within the tank 40.

[0035] The vertical circulation flow J, as shown in Figures 4(c) and (d), indicates the direction in which the slurry S flows within the tank 40, and represents a vertical flow perpendicular to the circumferential direction.

[0036] The vertical flow guide vanes 70 play a role in promoting vertical stirring provided in the vertical shielding plate 60, and also in generating turbulence by arranging small protrusions in the flow field, thereby improving the stirring condition.

[0037] The inclination angle 80 is the mounting angle at which the vertical flow guide vanes 70, which are provided on the vertical shielding plate 60, are attached, and experimental results indicate that an angle of approximately 45 degrees is desirable.

[0038] The splash guard 31 is a shielding plate that protects the electrical system of the rotary drive unit 30 from short circuits caused by slurry S splashing from the rotating tank. While the splash guard 31 is not an essential component, it is desirable to provide it.

[0039] The stagnant region T is an area within the agitated slurry S where the relative velocity between the stirring blades and the liquid is low, resulting in a state that cannot be considered good agitation.

[0040] The laminar flow region L is a region where the velocity in directions other than the direction of travel is zero, and the flow is regular. Like water flowing from a tap, the water coming out of the faucet falls straight down, and its flow is regular, so that during agitation, it moves in a regular manner, sticking to the agitator blades.

[0041] The turbulent region R is a region exhibiting irregular flow due to the presence of velocity components other than the direction of travel. This phenomenon occurs when the inertial force, which tends to maintain a constant state, is greater than the viscous force, which resists fluid movement. As a result, the fluid flows freely and irregularly away from the agitator blades.

[0042] Whether laminar or turbulent flow occurs depends on the conditions. As shown in Figure 4(a), laminar flow L is more likely to occur when the size (typical diameter) of the stirring blades 50 is small and the rotation speed is low, while turbulent flow R is more likely to occur when the size of the stirring blades 50 is large and the rotation speed is high, as shown in Figures 4(c) and (d).

[0043] Although the size and rotation speed of the stirring blade 50 vary depending on specifications such as the diameter of the tank 40, the manufacturer designs and develops the stirring blade 50 assuming normal use. Therefore, it is based on stirring that generates turbulence, and unless there are problems or errors in use, it can be said that the possibility of laminar flow occurring in the agitator is low.

[0044] Furthermore, as shown in Figure 4(b), the circumferential circulating flow E (horizontal rotation (tangential) flow) is a flow that circulates around the rotating stirring blade 50. This phenomenon occurs when the relative velocity between the stirring blade 50 and the liquid is small, and the positional relationship (distance) remains almost unchanged, making stirring impossible even if desired. Therefore, effective stirring cannot be expected with a circumferential circulating flow E (horizontal rotation (tangential) flow).

[0045] In contrast, vertical circulation flow J (axial flow / radial flow) occurs because the relative velocity between the stirring blades 50 and the liquid increases, causing a change in their positional relationship (distance), resulting in vertical circulation flow J relative to the stirring blades 50. Considering the purpose of mixing, axial flow / radial flow is the better agitation. Therefore, for efficient agitation, it is better to consider turbulence. In turbulent flow, the density is high and the viscosity is low. Conversely, laminar flow tends to result in a state of low density and high viscosity, so it is preferable to use a stirrer that can agitate while taking into account the fluid factors that cause turbulence.

[0046] Motor M is a prime mover positioned within the rotational drive unit 30 to rotate the tank 40, converting electrical energy into mechanical energy. Generally, it converts the force generated by the interaction of a magnetic field and electric current into rotational motion, and converts the flow of electricity into rotational motion, thereby rotating the tank 40 according to the present invention. There are many different types of motor M. For example, in a three-phase induction motor in AC motors, a rotating magnetic field is generated using current supplied sequentially in three phases to the coils of the stator, which induces an electric field in the form of a coil or cage, driving the rotor. On the other hand, brushed DC motors in DC motors are widely used in industrial and automotive applications such as robots. If only unidirectional rotation of the tank 40 is required, the speed of motor M can be controlled by changing the voltage applied to motor M using a single-switch topology with PWM (Pulse Width Modulation). On the other hand, if positioning or bidirectional rotation is required, a full H-bridge with PWM control can be used.

[0047] Pulley P is a disc-shaped component used for power transmission between pulleys to transmit rotational force generated by motor M to tank 40, and is used together with transmission belt V. While other power transmission mechanisms such as gears exist, a distinctive feature of the V-pulley is that, compared to gears, there is slippage between belt V and pulley P, which allows for some degree of absorption of the effects of problems that occur during the power transmission process. However, due to the slippage, the power transmission efficiency may be lower compared to other power transmission mechanisms. General-purpose V-pulleys are specified in "JIS B1854" and are used in combination with the transmission belt V according to the present invention. They have a V-shaped groove on the circumference of the disc, and because the contact area is large, there is less slippage, resulting in higher transmission efficiency compared to flat pulleys without grooves. V-pulleys can handle loads of various sizes and are therefore used in a wide range of products such as home appliances, machine tools, and transportation equipment.

[0048] The transmission belt V is a component used for power transmission between pulleys P to transmit the rotational force generated by the motor M to the tank 40. It is a ring made of a flexible material, and in addition to the common V-belt, there are also flat belts and toothed belts. A V-belt has a structure in which the outer circumference is wider and the inner circumference is narrower, forming a V-shape like an inverted trapezoid. Compared to a normal flat belt, it is characterized by its high frictional force, less slippage and greater transmission force, and is highly flexible for industrial machinery and is used in a variety of industrial machines. There are two types of V-belts, standard and red. Although the red type is more expensive, it is a high-performance product developed for high-electric applications with excellent resistance to high power, oil, heat, and durability, and is therefore preferable to use. Alternatively, it is also effective to use a V-ribbed belt, which combines the advantages of the flexibility of a flat belt and the strong frictional force of a V-belt, and the selection should correspond to the type of pulley P.

[0049] Figure 3 is an explanatory cross-sectional view illustrating the arrangement of the stirring blades and vertical shielding plate in the precision casting slurry stirring device according to the present invention. Figure 3(a) is an explanatory cross-sectional view AA illustrating the arrangement of the stirring blades and vertical shielding plate in relation to the rotating tank in the precision casting slurry stirring device according to the present invention. Figure 3(b) is an explanatory cross-sectional view BB illustrating the arrangement of the stirring blades and vertical shielding plate in the precision casting slurry stirring device according to the present invention.

[0050] As shown in Figure 3(a), the arm section 20 is fixed to the base 10 and the vertical flat plate 60 is fixed from above the tank 40. The tank 40, which is rotationally driven by the drive unit 30, is driven, for example, by a motor M whose rotational speed is limited by an inverter limiter I, via a belt V and pulley P. However, these drive methods are not particularly limited, and a servo motor controlled by PWM may also be used.

[0051] Furthermore, it is desirable to provide the rotating tank 40 with a splash-proof cover 41 fixed to the base 10 to prevent the slurry S from splashing.

[0052] Figure 4 is an explanatory diagram illustrating the stirring state of the slurry in the slurry stirring device for precision casting according to the present invention. Figure 4(a) is an explanatory diagram illustrating the stirring state in the slurry stirring device for precision casting according to the present invention. Figure 4(b) shows a state in which laminar flow occurs horizontally and local stagnation T occurs horizontally in the slurry stirring device 1 for precision casting according to the present invention. Figure 4(c) shows that a relatively good stirring state is achieved by the horizontal circulating flow E and the vertical circulating flow J. Figure 4(d) shows that when vertical flow guide vanes 70 are provided on the shielding plate 60, a good stirring state is achieved by the horizontal circulating flow E and the vertical circulating flow J.

[0053] Figure 5 is an explanatory diagram of a vertical shield plate in a precision casting slurry stirring apparatus according to the present invention, illustrating a vertical shield plate with vertical flow guide vanes attached to the vertical shield plate. Figure 5(a) is a plan view seen from above, Figure 5(b) is a front view seen from the side, Figure 5(c) is a side view seen from the side, and Figure 5(d) is a perspective view.

[0054] The vertical shielding plate 60 shown in Figure 5 is also called a baffle plate, and as the name suggests, it is a plate that "obstructs" the flow. By installing it in a fluid flow field, it generates vertical circulating flow J (turbulence), changing the direction and speed of the flow to separate suspended particles. Note that what is called a baffle plate is the same thing.

[0055] Conventionally, it has been possible to create turbulence by eccentrically mounting the stirring blades without using baffles. However, the problem of stress on the shaft remained. Therefore, in the precision casting slurry stirring device 1 according to the present invention, by adopting a flat plate shape for the vertical shielding plate 60, it is possible to generate turbulence without placing a large load on the vertical shielding plate 60. Furthermore, by providing vertical flow guide blades 70 as shown in Figure 5, it is possible to adopt a configuration that allows for further changes in the direction and speed of the flow to separate and mix suspended particles, and further to homogenize the temperature and concentration.

[0056] Figure 6 is an explanatory diagram of the experimental state of the precision casting slurry stirring apparatus according to the present invention. Scaled-down Figure 6(a) shows the state when two vertical shielding plates 60 are installed, illustrating an experimental state where the solid material dispersed throughout the tank is well dispersed with the liquid. Figure 6(b) shows the stirring state when the tank is rotated using only the stirring blades, illustrating an experimental state where a layered laminar flow section L is formed horizontally at the bottom of the tank. The illustrated experiment involved a solid material with a specific gravity of 1.01 to 1.03 g / cm³. 3 The experiment was conducted using the WAX, with three types of liquids: water, viscometer calibration standard solution JS 1000 LOT No. 159: 25°C 606.6 mPa·s, and viscometer calibration standard solution JS 500 LOT No. 170: 25°C 309.2 mPa·s. The diameter of tank 40 was 120 mm, the depth of tank 40 was 112.7 mm, the motor rotation speed was 55 rpm, and the peripheral speed was 0.35 m / s. In addition, tests were also conducted using a mass production tank, with a tank diameter of 790 mm, a depth of 690 mm, a motor rotation speed of 29 rpm, and a peripheral speed of 1.2 m / s, achieving a similarly good stirring state to the three viscosity conditions mentioned above.

[0057] Figure 7 is an explanatory diagram of the experimental apparatus used in the experiment shown in Figure 6. Figure 7(a) shows a front view of the experimental apparatus, and Figure 7(b) shows a side view. The stirring device shown in Figure 6 is a 1 / 10 scale model made for the experiment, and the details are as shown in Figure 7. In order to rotate the tank 40, a fixing device K is provided to fix the tank 40 to a rotary table, and the rotational force is transmitted by a coupling N that joins the rotating shaft that supports the rotation of the tank 40 with the output shaft of the motor M which is arranged in a substantially linear manner. Note that the motor M shown in Figure 7(b) has a geared head (reduction gear) incorporated into it, so the output shaft is positioned eccentrically. Explanations of similar components such as the stirring blades 50 and vertical shielding plates 60 are omitted. [Industrial applicability]

[0058] One casting method for precision castings is the "lost-wax method." The characteristic of this "lost-wax method" is that it can produce products with high dimensional accuracy, especially those made of materials that are difficult to machine and those with complex shapes. In the midst of the growing concern over global warming, this method is indispensable for producing heat-resistant turbine blades necessary for improving the thermal efficiency of gas turbine combined cycle power generation, which is attracting attention worldwide as an effective countermeasure. In particular, in the production of high-precision castings that utilize advanced technology to create cavities (holes) through which air or steam flows to cool the blades so that they can withstand the high temperatures at the gas turbine inlet, the presence of a stirring device that enables uniform particle dispersion and bubble removal is extremely important, and is considered to have high industrial applicability. [Explanation of symbols]

[0059] 1. Slurry stirring device for precision casting 10 bases 20 Arm section 30 Rotary drive unit 31 Shatter prevention plate 40 tanks 41. Shatterproof cover 42 Inner surface 43 Bottom 50 stirring blades 51. Rake angle 60 Vertical shielding plate 70 Vertical flow guide vanes 80 degrees of inclination E Circumferential circulation flow J Vertical circulation flow S Slurry T stagnation part L laminar flow section R Turbulence section M Motor P Pulley V-type transmission belt I. Inverter control N coupling K fixation device

Claims

1. A slurry stirring device (1) for precision casting, which stirs a slurry (S) that is a solid-liquid two-phase fluid consisting of a liquid phase and powdered particles, A base (10), an arm portion (20) fixed to the base (10), Rotary drive unit (30) and A tank (40) that is rotated by the rotary drive unit (30), A stirring blade (50) is fixedly positioned at the bottom of the tank (40), It consists of a vertical shielding plate (60) fixed to the arm portion (20) and positioned on the side inside the tank (40), The stirring blade (50) is formed such that a predetermined scoop angle (51) is always maintained with respect to the tangential direction of the inner circumferential surface (42) of the tank (40) and the bottom surface (43). A slurry stirring device (1) for precision casting, characterized by generating not only a circulating flow (E) in the circulating direction but also a circulating flow (J) in the vertical direction to prevent the slurry (S) from settling.

2. The precision casting slurry stirring device (1) according to claim 1, characterized in that a plurality of the vertical shielding plates (60) are provided.

3. The precision casting slurry stirring device (1) according to claim 1 or 2, characterized in that the vertical shielding plate (60) is provided with vertical flow guide vanes (70).

4. The precision casting slurry stirring apparatus (1) according to claim 3, characterized in that the inclination angle (80) of the vertical flow guide vanes (70) provided on the vertical shielding plate (60) is within the range of 40 to 50 degrees.

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