Precision casting slurry mixing equipment

Abstract

The present invention provides an agitation device for precision casting, and more specifically, an agitation device for precision casting slurry that generates a vertical circulating flow by rotating a tank, prevents slurry settling, and extends the service life of conventional devices. [Solution] The present invention is a precision casting slurry stirring device for stirring slurry, which is a solid-liquid two-phase fluid consisting of a liquid phase and powdered particles, and comprises a base, an arm unit fixed to the base, a rotary drive unit, a tank rotated by the rotary drive unit, a stirring blade fixed to the arm unit and positioned at the bottom of the tank, and a vertical shielding plate fixed to the arm unit and positioned at the side of the tank, and is configured to generate not only a circumferential circulating flow but also an up-down circulating flow to prevent the slurry from settling.

Description

[Technical Field]

[0001] The present invention relates to a stirring device for precision casting, and more specifically to a stirring device technology that, when stirring a viscous material, increases the relative velocity between the stirring blades and the liquid by fixing a baffle plate to a base and rotating a stirring tank, thereby generating turbulence and creating a circulating flow in the circumferential direction and in the vertical direction, thereby achieving a good diffusion effect without stagnation. [Background technology]

[0002] The "lost wax" method is a casting method for precision casting. The feature of this casting method is that it can produce products with high dimensional accuracy, especially those made of materials that are difficult to machine and with complex shapes. As the issue of global warming has come into the spotlight in recent years, the lost wax method is an essential technology for producing turbine blades with excellent heat resistance, which are necessary to improve the thermal efficiency of gas turbine combined cycle power generation, which is attracting attention worldwide as an effective countermeasure.

[0003] In particular, in order to cool the turbine blades so that they can withstand the gas turbine inlet temperature of 1,650°C, advanced technology is required to create cavities (holes) within the blades that allow air and steam to flow.At the same time, in precision casting using the lost-wax method, the uniform mixing of the slurry has a significant impact on the quality of the final product, so the slurry mixing device can be said to be a device that plays an important role in precision casting using the lost-wax method.

[0004] The roles of a slurry mixer are to achieve uniform particle dispersion, remove air bubbles, and adjust viscosity. Uniform particle dispersion allows the ceramic particles and binder in the slurry to be evenly dispersed, improving the strength and dimensional accuracy when creating a mold. Air bubble removal effectively removes air bubbles that occur during mixing, reducing voids in the mold and increasing the density of the product. Mixing adjusts the viscosity of the slurry, optimizing its ability to fill the mold and its surface finish. Mixing equipment also has a significant impact on contributing to product quality, productivity, and cost reduction. In other words, a uniform slurry evens out mold shrinkage and improves the dimensional accuracy of the product, while a slurry with fewer air bubbles smooths the surface of the mold and improves the surface finish of the product. Uniform particle dispersion also improves mold strength and prevents product damage.

[0005] Conventional agitators use a rotating impeller inserted into a suspension containing dispersed, suspended fine solid particles to generate a circumferential circulating flow. However, unless the impeller's position is moved vertically, layered stagnation occurs, preventing uniform agitation. Furthermore, when the suspension is viscous, a large torque is required to rotate the impeller in the suspension, potentially damaging the impeller. Furthermore, in precision casting processes such as the lost-wax casting process, a part model is immersed in a slurry in a tank to produce a model mold that serves as the prototype for the casting mold, making it difficult to install an impeller inside the tank. For this reason, commonly used tank structures include one in which the impeller rotates within a fixed tank, one in which a flat baffle plate is placed within a rotating tank, or one in which the baffle plate rotates within a fixed tank. However, all of these configurations create turbulent flow while also generating circulating flow in both the vertical and circumferential directions, resulting in problems such as poor diffusion without stagnation and the formation of stagnation.

[0006] In light of this current situation, various technical proposals have been made in the past. The title of the invention is "Slurry Storage Tank," the problem to be solved is "To provide a storage tank for slurry used to coat fugitive patterns in an investment storage method," and the solution is "comprised of a tank body with an open top and fixed in position, a baffle plate disposed within the tank body with its surface near the outer periphery facing the direction of movement, and a drive means for moving the baffle plate along the inner wall surface of the tank body." However, because this technology employs a drive means for moving the baffle plate along the inner wall surface of the tank body, it does not solve the problem of the large load on the baffle plate, making it prone to breakage. Furthermore, it can be said that the technical means for solving the problem is different in that it does not employ a drive means for rotating the tank body as in the present application.

[0007] The invention is titled "Slurry Agitator," and the problem to be solved is "to provide a slurry agitator capable of efficiently utilizing the fast flow generated near the tank inner wall to generate a vertical circulating flow, preventing the slurry from settling and improving performance." The specific solution is described as "inserting agitation means into the tank to generate a vertical circulating flow from the circumferential flow of the slurry generated as the tank rotates, and the agitation means is configured as an L-shaped agitation member consisting of a hollow vertical agitation blade portion and a hollow horizontal agitation blade portion" (Patent Document 2). The technology described in Patent Document 2 and the present invention share the common feature of a rotating tank and a fixed vertical agitation blade. However, while the technology described in Patent Document 2 uses an L-shaped member in which the vertical agitation blade portion and the horizontal agitation blade portion are integrated, and the horizontal agitation blade portion is also fixed relative to the rotating tank, the present invention uses an agitation blade installed horizontally along with the tank, and the load on the blade and the means for directing the horizontal flow are different.

[0008] The title of the invention is "Agitation Device for Kneaded Material," and the problem to be solved is "To prevent the formation of accumulation areas of the kneaded material and promote turbulence." The specific solution is as follows: "When the round can is rotating, the agitator blade contacts the inner circumferential surface of the round can for a predetermined period of time, preventing the kneaded material from moving and directing it toward the center of the can for agitation. After a predetermined time has passed, the agitator blade moves away from the inner circumferential surface, causing the kneaded material in the accumulation areas before and after the agitator blade to separate from the agitator blade. Next, the moving agitator blade obstructs the kneaded material adhering to the inner circumferential surface of the can, and this agitation is effectively repeated." This technology is similar to the present invention in that the round can, which contains the kneaded material, rotates and agitates the material with a fixed agitator blade. However, the technology described in Patent Document 3 moves the agitator blade's position at predetermined time intervals, and the technical means for solving the problem is different. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Practical Application No. 61-63339 [Patent Document 2] Patent Publication No. 2005-270758 [Patent Document 3] Japanese Patent Application Publication No. 7-171369 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide an agitation device for precision casting, and more specifically, to provide a slurry agitation device that generates a circulating flow in an up and down direction by rotating a tank, prevents settling of the slurry, and can extend the service life of each conventional device. More specifically, an object of the present invention is to provide a technology for an agitation device that, when agitating a viscous material, increases the relative speed between the agitating blades and the liquid by rotating the agitation tank, generates turbulence while creating a circulating flow in the circumferential direction and up and down, and achieves good diffusion without stagnation. [Means for solving the problem]

[0011] The present invention is a precision casting slurry stirring device for stirring slurry, which is a solid-liquid two-phase fluid consisting of a liquid phase and powdered particles, and comprises a base, an arm portion fixed to the base, a rotary drive portion, a tank rotated by the rotary drive portion, a stirring blade fixed to the bottom of the tank, and a vertical shielding plate fixed to the arm portion and placed on the side of the tank, and the stirring blade is formed so as to always maintain a predetermined rake angle with respect to the tangential direction of the inner surface of the tank and the bottom surface, and a structural means is adopted which generates not only a circumferential circulating flow but also an up-and-down circulating flow to prevent the slurry from settling.

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

[0013] The present invention may also employ a configuration in which the vertical shielding plate is provided with vertical flow guide vanes.

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

[0015] In conventional fixed tanks with rotating stirring blades, only a circumferential flow is generated, but the stirring device for precision casting of the present invention can generate a vertical circumferential flow, which has the excellent effect of significantly reducing the settling of the refractory material that makes up the slurry at the bottom of the tank.

[0016] Furthermore, the stirring device for precision casting according to the present invention generates not only a circumferential circulation flow but also an up-and-down circulation flow, thereby providing the excellent effect of sufficiently stirring the interior of the tank and extending the period during which the slurry can be used.

[0017] Furthermore, with the stirring device for precision casting according to the present invention, the stirring blades do not rotate, but the tank rotates, and therefore the stirring blades are not driven in the viscous slurry, which means that the load on the stirring blades is reduced and they are less likely to break, demonstrating excellent durability.

[0018] Furthermore, when the precision casting slurry stirring device according to the present invention is configured to include multiple vertical shielding plates, a vertical circulating flow is generated for each vertical shielding plate, thereby providing the excellent effect of sufficiently stirring the interior of the tank and making it possible to obtain a homogeneous slurry.

[0019] Furthermore, in the precision casting slurry stirring device according to the present invention, when a configuration is adopted in which vertical flow guide blades are provided on the vertical shielding plates, a larger vertical circulation flow is generated for each vertical shielding plate that is placed, thereby achieving the excellent effect of sufficiently stirring the inside of the tank and making it possible to obtain a more homogeneous slurry.

[0020] Furthermore, in the precision casting slurry stirring device according to the present invention, when a configuration is adopted in which the inclination angle of the vertical flow guide blades provided on the vertical shielding plates is within the range of 40 to 50 degrees, a larger vertical circulation flow is generated for each vertical shielding plate arranged, thereby achieving the excellent effect of sufficiently stirring the inside of the tank and making it possible to obtain a more homogeneous slurry. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view illustrating the basic configuration of a precision casting slurry stirring device according to the present invention; [Figure 2] 1 is a plan view illustrating the basic configuration of a precision casting slurry stirring device according to the present invention; [Figure 3] 1 is an explanatory cross-sectional view illustrating the arrangement of stirring blades and vertical shielding plates in a slurry stirring device for precision casting according to the present invention. FIG. [Figure 4]1 is a diagram illustrating the stirring state of a slurry in a precision casting slurry stirring device according to the present invention; FIG. [Figure 5] 1 is a vertical shielding plate explanatory diagram illustrating a vertical shielding plate in a precision casting slurry stirring device according to the present invention and a vertical shielding plate having a configuration in which vertical flow guide blades are attached to the vertical shielding plate. FIG. [Figure 6] FIG. 2 is an explanatory diagram showing an experimental state of the precision casting slurry stirring device according to the present invention. [Figure 7] FIG. 1 is an explanatory diagram showing the configuration of an experimental device used in an experiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention relates to a precision casting slurry stirring device comprising a base, an arm fixed to the base, a rotary drive, a tank rotated by the rotary drive, a stirring blade fixed to the bottom of the tank, and a vertical shield plate fixed to the arm and positioned on one side of the tank. The stirring blade is formed to always maintain a predetermined rake angle with respect to the tangential direction of the inner circumferential surface of the tank and the bottom, thereby generating not only a circumferential circulating flow but also a vertical circulating flow to prevent the slurry from settling. The following description is based on the drawings. However, the shape and configuration of the device are not limited to those shown in the drawings, and modifications may be made within the scope of the invention's technical concept.

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

[0024] Figure 2 is a plan view illustrating the basic configuration of a slurry stirring device for precision casting according to the present invention, where Figure 2(a) shows a plan view as viewed from above and Figure 2(b) shows a front view as viewed from a horizontal direction.

[0025] The precision casting slurry mixing device 1 is a mixing device for mixing slurry S, a solid-liquid two-phase fluid consisting of a liquid phase and powder particles. It comprises a base 10, an arm 20 fixed to the base 10, a rotary drive 30, a tank 40 rotated by the rotary drive 30, a mixing blade 50 fixed to the bottom of the tank 40, and a vertical shielding plate 60 fixed to the arm 20 and positioned on one side of the tank 40. The mixing blade 50 is formed to always maintain a predetermined rake angle 51 with respect to the tangential direction of the inner circumferential surface 42 of the tank 40 and the bottom surface 43. This generates not only a circumferential circulating flow E but also a vertical circulating flow J to prevent the slurry S from settling. When selecting a mixing device, the following points should be taken into consideration. It is necessary to select a mixing device that matches the characteristics of the slurry S, such as viscosity, particle size, and solids concentration; to select a device that matches the desired mixing effect, such as homogenization, degassing, or viscosity adjustment; and to select a device with an appropriate processing capacity based on the production volume. Therefore, slurry mixing devices in precision casting are important devices that greatly contribute to improving product quality, productivity, and cost reduction. By selecting the appropriate mixing device based on the slurry characteristics and manufacturing conditions and setting optimal mixing conditions, it is possible to consistently manufacture high-quality products. Each component will be explained below.

[0026] Slurry S is a suspension or solid-liquid mixture in which minute solid particles are dispersed and suspended throughout a liquid, and is also called a mud. The viscosity coefficient tends to change depending on the proportion of minute solid particles mixed in. In many cases, a Newtonian fluid changes to a non-Newtonian fluid as the solid concentration increases, and depending on how the viscosity coefficient changes, some become like a Bingham fluid, while others become dilatant.

[0027] The base 10 is a base unit that holds the tank 40, which is rotated and driven by the rotation drive unit 30. The base 10 also includes an arm unit 20 for installing the vertical shielding plate 60 in a fixed state relative to the tank 40, which is rotated.

[0028] The arm portion 20 is fixed to the base 10 and holds the vertical shielding plate 60 in a fixed manner relative to the rotation of the tank 40 .

[0029] The rotary drive unit 30 is a device for rotating the tank 40, and is provided with a motor M, a power supply, an inverter control board for controlling the rotation speed, etc., mounted on the base 10. Note that the rotary drive unit 30 is preferably covered with a housing or waterproof plate as shown in the drawings to prevent electrical leakage.

[0030] The tank 40 is a container for stirring the slurry S, and is rotated by the rotation drive unit 30.

[0031] The stirring blade 50 is fixed to the tank 40 and generates a circumferential circulating flow E for the slurry S. Note that what is shown in the drawings is merely an example, and the shape and number of propellers are not particularly limited, and include those that exhibit the same effects as the effects of the present invention.

[0032] The rake angle 51 is the angle at which each blade of the agitator blade 50 rises relative to the horizontal. By setting such a rake angle, it becomes possible to smoothly agitate even highly viscous slurry S without forming a stagnation area T above the agitator blade 50, and it also makes it easier to create a vertical circulation flow J.

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

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

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

[0036] The vertical flow guide blades 70 are provided on the vertical shielding plate 60 and serve to promote vertical mixing, and by placing small protrusions in the flow field, they generate turbulence and improve the mixing condition.

[0037] The inclination angle 80 is the angle at which the vertical flow guide vanes 70 are attached to the vertical shielding plate 60, and experimental results have shown that it is preferably about 45 degrees.

[0038] The anti-scattering plate 31 is a shielding plate for preventing the slurry S from scattering from the rotating tank and causing a short circuit or the like in the electrical system of the rotary drive unit 30. The anti-scattering plate 31 is not an essential component, but it is desirable to provide it.

[0039] The stagnation portion T indicates an area inside the slurry S being stirred where the relative speed between the stirring blades and the liquid is low and the stirring state cannot be said to be good.

[0040] The laminar flow region L is a region where the velocity is zero in any direction other than the direction of travel and where the flow is regular. Like water flowing from a tap, water that comes out of a faucet falls straight down, and its flow is regular, and when stirred, it moves in a regular manner, adhering to the stirring blades.

[0041] The turbulent flow region R is an area that exhibits irregular flow due to the presence of components related to speed other than the direction of travel. This phenomenon occurs when the inertial force, which tends to maintain the same state, is greater than the viscous force, which indicates the difficulty of fluid movement, and the fluid flows freely and irregularly away from the stirring blades.

[0042] Whether laminar or turbulent flow occurs depends on the conditions. As shown in Figure 4(a), laminar flow region L is likely to occur when the size (representative diameter) of the agitator blade 50 is small and the rotation speed is low, while turbulent flow region R is likely to occur when the size of the agitator blade 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 agitator blade 50 differ depending on the diameter of the tank 40 and other specifications, the manufacturer designs and develops the agitator blade 50 assuming normal use, and therefore it is made based on agitation that creates turbulence, so it can be said that there is little chance of laminar flow occurring in the agitator unless there is a problem or an error in usage.

[0044] Furthermore, as shown in Figure 4(b), the circumferential circulating flow E (horizontal rotational (tangential) flow) is a flow that circulates around the rotating agitator blade 50, and is a phenomenon that occurs when the relative speed between the agitator blade 50 and the liquid is small, in which case the positional relationship (distance) remains almost unchanged, and agitation is not possible even if desired. Therefore, effective agitation cannot be expected with the circumferential circulating flow E (horizontal rotational (tangential) flow).

[0045] In contrast, vertical circulating flow J (axial flow / radial flow) occurs when the relative speed between the impeller 50 and the liquid increases, causing the positional relationship (distance) to fluctuate, resulting in vertical circulating flow J relative to the impeller 50. Considering the goal of mixing, this state is better for mixing with axial / radial flow. Therefore, for efficient mixing, it is better to be aware of turbulence. Turbulent flow results in a state of high density and low viscosity. Conversely, laminar flow tends to result in a state of low density and high viscosity, so it is best to choose a mixer that can mix while taking into account the fluid factors that cause turbulence.

[0046] The motor M is a prime mover that converts electrical energy into mechanical energy and is located within the rotary drive unit 30 to rotate the tank 40. A motor that converts the force generated by the interaction of a magnetic field and an electric current into rotary motion typically converts electrical power into rotational motion, and it drives the tank 40 of the present invention. There are many different types of motors M. For example, a three-phase induction motor, which is an AC motor, generates a rotating magnetic field by supplying three phases of current sequentially to the stator coil, which then induces a coil-shaped or cage-shaped electric field to drive the rotor. On the other hand, brushed DC motors, which are DC motors, are widely used in industrial and automotive applications such as robots. When only unidirectional rotation of the tank 40 is required, a single-switch topology using pulse width modulation (PWM) can be used to vary the voltage applied to the motor M and control the speed of the motor M. On the other hand, when positioning or bidirectional rotation is required, a full H-bridge with PWM control can be used.

[0047] Pulleys P are disk-shaped components used to transmit power between pulleys P, transmitting the rotational force generated by motor M to tank 40, and are used together with transmission belt V. While other power transmission mechanisms, such as gears, exist in addition to pulleys P, slippage between belt V and pulley P, unlike gears, allows for some degree of absorption of the impact of any problems that may occur during the power transmission process. However, due to slippage, power transmission efficiency may be lower than with other power transmission mechanisms. General-purpose V-pulleys are specified in JIS B1854 and are used in combination with the transmission belt V of the present invention. They feature V-shaped grooves on the circumference of the disk, which reduces slippage due to a large contact area, resulting in higher transmission efficiency compared to flat pulleys without grooves. V-pulleys can accommodate a wide range of loads, making them popular in a wide range of products, including home appliances, machine tools, and transportation equipment.

[0048] The transmission belt V is a component used to transmit power between pulleys P, transmitting the torque generated by motor M to tank 40. It is a ring made of a flexible material, and can be a standard V-belt, a flat belt, or a toothed belt. V-belts are wider on the outer periphery and narrower on the inner periphery, forming an inverted trapezoidal V-shape. Compared to standard flat belts, they offer higher friction, less slippage, and greater transmission power. They are also highly flexible and used in a variety of industrial machinery. V-belts come in two types: standard and red. While more expensive, red belts are developed as high-performance belts with excellent power, oil resistance, heat resistance, and durability. They are therefore suitable for use with high-power applications. Alternatively, V-ribbed belts, which combine the flexibility of flat belts with the high friction of V-belts, can be used, depending on the type of pulley P.

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

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

[0051] It is desirable that the rotating tank 40 be provided with a scattering prevention cover 41 fixed to the base 10 in order to prevent the slurry S from scattering.

[0052] Figure 4 is an explanatory diagram of 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 of the stirring state of the slurry in the slurry stirring device for precision casting according to the present invention, Figure 4(b) shows a state in which a laminar flow occurs in the horizontal direction in the slurry stirring device for precision casting 1 according to the present invention, and a local stagnation area T occurs in the horizontal direction, Figure 4(c) shows that a relatively good stirring state is achieved by the horizontal circulating flow E and the vertical circulating flow J, and Figure 4(d) shows that when vertical flow guide blades 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 shielding plate in a precision casting slurry stirring device according to the present invention, illustrating a vertical shielding plate and a vertical shielding plate having an up-and-down flow guide blade attached to the vertical shielding plate, where Figure 5(a) is a plan view from above, Figure 5(b) is a front view from the side, Figure 5(c) is a side view from the side, and Figure 5(d) is an oblique view.

[0054] The vertical shielding plate 60 shown in Fig. 5 is also called a baffle plate, and as the name suggests, it is a plate that "interferes" with the flow. When installed in the flow field of a fluid, it generates a vertical circulating flow J (turbulent flow) and changes the direction and speed of the flow to separate suspended particles. Note that this is the same as what is called a baffle plate.

[0055] Conventionally, it has been possible to generate turbulence by eccentrically mounting the stirring blades without using baffles. However, the problem of strain on the shaft remained. Therefore, in the precision casting slurry stirring device 1 according to the present invention, a flat vertical shielding plate 60 is used, which allows turbulence to be generated without placing a large strain on the vertical shielding plate 60. Furthermore, by providing vertical flow guide blades 70 as shown in FIG. 5, a configuration can be adopted in which the direction and speed of the flow can be changed to separate and mix suspended particles, and further temperature and concentration can be homogenized.

[0056] 6A and 6B are explanatory diagrams showing experimental conditions of an apparatus for stirring slurry for precision casting according to the present invention. Scaled-down Fig. 6A shows the state when two vertical shielding plates 60 are attached, showing the experimental condition in which solids dispersed throughout the tank are well dispersed with the liquid, and Fig. 6B shows the stirring condition when the tank is rotated only by the stirring blades, showing the experimental condition in which a laminar flow section L is formed in the horizontal direction at the bottom of the tank. The illustrated experiment was carried out using solids with a specific gravity of 1.01 to 1.03 g / cm3. 3 The experiment was conducted using three types of wax: water, JS 1000 LOT No. 159 (25°C, 606.6 mPa·s), and JS 500 LOT No. 170 (25°C, 309.2 mPa·s). The tank 40 diameter was 120 mm, the tank 40 depth was 112.7 mm, the motor rotation speed was 55 rpm, and the peripheral speed was 0.35 m / s. Tests were also conducted using a mass-produced tank, with a tank 40 diameter of 790 mm, a tank 40 depth of 690 mm, a motor rotation speed of 29 rpm, and a peripheral speed of 1.2 m / s. Similar good mixing results were obtained under the three viscosity conditions.

[0057] FIG. 7 is an explanatory diagram of the experimental apparatus used in the experiment shown in FIG. 6 , with FIG. 7(a) showing a front view and FIG. 7(b) showing a side view. The mixing apparatus shown in FIG. 6 is a 1 / 10 scale mixer manufactured for the experiment, and is shown in detail in FIG. 7 . To rotate the tank 40, a fixing device K is provided to fix the tank 40 to a rotary table. The rotational force is transmitted via a coupling N, which connects the rotating shaft supporting the tank 40 to the output shaft of a motor M, which is arranged in a substantially linear fashion. Note that the motor M shown in FIG. 7(b) incorporates a geared head (reduction gear), so the output shaft is positioned eccentrically. Explanations of similar components, such as the mixing blade 50 and vertical shielding plate 60, are omitted. [Industrial Applicability]

[0058] The "lost-wax" casting method is a casting method for precision castings. The "lost-wax" method is characterized by its ability to produce products with high dimensional accuracy, particularly for materials and complex shapes that are difficult to machine. This method is essential for producing turbine blades with excellent heat resistance, which are essential for improving the thermal efficiency of gas turbine combined-cycle power generation, which is attracting worldwide attention as an effective countermeasure to global warming. In particular, the production of high-precision precision castings requires advanced technology to create cavities (holes) within the blades that allow air or steam to flow through them in order to cool the blades so that they can withstand the high inlet temperatures of gas turbines. A stirring device that enables uniform particle dispersion and air bubble removal is extremely important, and the lost-wax method is believed to have great industrial applicability. [Explanation of symbols]

[0059] 1. Precision casting slurry mixing device 10 Foundations 20 Arm section 30 Rotation drive unit 31 Shatter prevention plate 40 Tank 41 Anti-scattering cover 42 Inner surface 43 bottom 50 stirring blade 51 Rake angle 60 Vertical shielding plate 70 Vertical flow guide vane 80 tilt angle E Circumferential circumferential flow J Vertical circulation flow S Slurry T stagnation part L laminar flow section R Turbulence section Medium motor P pulley V Transmission Belt I Inverter control N Coupling K fixation device

Claims

1. A precision casting slurry stirring device (1) for stirring a slurry (S) that is a solid-liquid two-phase fluid of a liquid phase and powder particles, a base (10), an arm portion (20) fixed to the base (10), A rotary drive unit (30); a tank (40) rotated by the rotary drive unit (30); an agitating blade (50) fixed to the bottom of the tank (40); a vertical shielding plate (60) fixed to the arm portion (20) and arranged on the side of the tank (40); The stirring blade (50) is formed so as to always maintain a predetermined rake angle (51) with respect to the tangential direction of the inner peripheral surface (42) of the tank (40) and the bottom surface (43), A precision casting slurry stirring device (1) that generates not only a circumferential circulating flow (E) but also a vertical circulating flow (J) to prevent the slurry (S) from settling.

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

4. 4. A precision casting slurry stirring device (1) as described in 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 degrees to 50 degrees.

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