JPH09253790A - Pluidized vessel for coating powdery and granular material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluidized vessel which can accurately stick powdery and granular materials to a material to be treated. SOLUTION: A venting bed 2 at the lower part of the vessel 1 and a gas supplying means 4 for supplying the gas from the lower part of the venting bed 2 are provided and the powdery and granular materials 9 to stick and coat the surface of the material 6 to be treated by the supplied gas are fluidized. A venting body 3 uniformly arranging disordered through-holes 3a over the whole surface, is provided on the venting bed 2 of the fluidized vessel for coating treatment to the powdery and granular materials, sticking the powdery and granular materials 9 on the material 6 to be treated by dipping the material 6 to be treated into the fluidized powdery and granular materials. Gas-tight pressure chamber 7A is formed at the lower part of the venting body 3 is formed and also, the gas supplying means 4 is arranged in the pressure chamber 7A so as to form a pressure space at the lower part of the venting bed 2 by supplied gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid tank for coating powder or granular material, and more specifically, it comprises a vented bed below the container and a gas supply means for supplying gas from below the vented bed.
The powder to be adhered to the surface of the object to be treated is fluidized by the supplied gas, and the object to be treated is immersed in the fluidized granular material to the object to be treated. The present invention relates to a fluid tank for coating a powder or granular material to which powder or granular material is attached.

[0002]

2. Description of the Related Art Conventionally, for example, in the technical field of precision casting, sand particles of a mold material, which is a stucco material for shell mold, are fluidized in a container of a fluidized tank, and the fluidized stucco material floats. The model for precision casting is immersed in a layer to be coated, and the particles of the stucco material are adhered to the surface of the model to be coated, and a fluid tank for powdery granule coating treatment as a precision casting mold fluidizing tank for molding. In this fluidized vessel, as shown in FIG. 4 (a), the vessel 1 of the fluidized vessel F is provided with a vented floor 2 that divides the vessel 1 into upper and lower parts.
A fluidized portion 10 is formed above the ventilated floor 2, and gas supply means 4 is provided below the ventilated floor 2 to form an air supply portion 7. As the ventilation floor 2, particles of the stucco material 9 are prevented from passing through the ventilation floor 2 and falling into the air supply portion 7 below, and at the same time, are formed in the upper fluidized portion 10 through the ventilation floor 2. In order to disperse the gas (hereinafter referred to as air supply) to be supplied to the fluidized bed 17 of 9 particles of the stucco material,
A combination of a fine wire mesh 12a and a coarse wire mesh 12b that supports the wire mesh from below is used. Then, in order to supply the air supply, as the gas supply means 4, the air supply portion 7 is laterally and airtightly inserted below the aeration floor 2, as shown in FIG. Is provided with a plurality of air supply holes 5a, and a plurality of gas supply pipes 5 for supplying gas upward are arranged so that the supply air is supplied upward.

[0003]

In the above-described conventional precision casting mold fluidizing tank, as described above, the ventilation floor 2 is composed of the wire nets 12a and 12b.
Air supply hole 5 of the gas supply pipe 5 provided in the air supply unit 7 below
Since the supply air is blown toward the ventilation floor 2 from a, the wire nets 12a and 12b have a high air permeability and hardly affect the direction of the gas flow passing through the wire nets. The supply air passes in the direction in which the air is blown, and the dynamic pressure and static pressure of the air flow of the supply air are simultaneously applied to the lower surface of the wire net 12b, so that the supply air jetted from the supply hole 5a directly arrives. However, since the dynamic pressure of the supply air does not act uniformly, the supply air for fluidizing the stucco material 9 particles on the ventilation floor 2 is not uniformly supplied to the ventilation floor 2, The airflow passing through the portion of the ventilated floor 2 having a large dynamic pressure of the supply air in the direction of the pores 5a is a stucco material 9 of the fluidized bed 11 on the ventilated floor 2.
The particles are strongly pushed up, and the airflow is dispersed from this portion and passes through the other portion where the dynamic pressure of the air supply is small, and pushes up the stucco material 9 particles of the fluidized bed 11 on the aerated floor 2. The strength is weaker than the former part, and as a result,
In addition to the unevenness of the flow velocity of the air supply, the ventilation resistance of the fluidized bed 11 is locally uneven, and the stucco material 9 particles are fluidized in the fluidized bed 11 formed on the aerated bed 2. There was a problem that the rising flow velocity of the supplied air was not uniform and the fluidized state of the fluidized bed 11 formed was not uniform.
In particular, when the stucco material is zircon sand, the density of the particles is large, so the ventilation flow is locally biased in the conventional structure, and the ventilation pressure is insufficient at the pressure conventionally used, and powder If the particles cannot be pushed up and the pressure is increased, the pressure is locally applied, and the positional change of the supply pressure becomes large, and the above-mentioned problem becomes remarkable. As a result, the grain size of the stucco material 9 is biased in the direction of the surface of the ventilation floor 2, and at the same time,
Since the stucco material 9 particles cannot be sufficiently suspended, it becomes difficult to immerse the stucco material 9 in the fluidized bed 11, and the stucco material 9 particles that are close to the surface of the model 6 that can be further immersed. As a result, it is difficult to deposit the stucco material 9 particles on the surface with high accuracy, and a shell mold having desired accuracy cannot be formed. Therefore, the object of the present invention is to solve the above problems, for example, in the case of molding a shell mold for precision casting, without causing a deviation in the particle size of the stucco material particles forming the fluidized portion, the stucco A fluidized bed that uniformly suspends material particles can be easily formed, and it is possible to accurately attach stucco material particles to a model when molding a precision casting mold. The present invention is to provide a fluidized tank for coating powder particles that can be adhered.

[0004]

[Means for Solving the Problems]

[First Characteristic Structure] The first characteristic structure of the fluid tank for coating powder and granular material of the present invention for the above-mentioned purpose is to form a fluidized bed of the powder and granular material for coating processing above it. The ventilation bed for supporting the powdery particles and at the same time distributing and supplying the supply air to form the fluidized bed is provided with a ventilation body having perforations in random directions uniformly over the entire surface thereof. An airtight pressurizing chamber is formed below the gas, and the gas supply means is provided in the pressurizing chamber so that the pressurizing space is formed below the aeration floor by the supplied gas. (Corresponding to 1) point. [Operation and Effect of First Characteristic Configuration] Therefore, according to the first characteristic structure, an airtight pressurizing chamber is formed below the ventilation body, and a gas supply unit is provided in the pressurizing chamber to supply gas ( (Hereinafter referred to as air supply), a pressure space is formed below the aeration bed, and the pressure space is pressurized by the static pressure of the air supply. Therefore, unlike the conventional case, a portion where the pressure from below is increased due to the dynamic pressure of the supply air is not locally generated in the aerated bed, and the air flow passing through this portion causes the flow on the aerated bed. It is possible to prevent the powder and granules in the layer from being strongly pushed up locally, and furthermore, since the ventilation body is made to have the disordered through-holes evenly over its entire surface, the disordered through-holes allow the passing air supply to pass through. The direction of is guided by the through hole If the ventilation body has a sufficient thickness, the pressure loss of the supply air flow passing through the ventilation body increases, and even if there is a portion where the flow direction of the supply air is different, The passing gas is guided by the through holes to disperse the flow direction, so that the flow direction after passing is not affected by the direction of the air flow below the aeration bed, and is uniform in the lower part of the layer of the granular material. As a result, it is possible to prevent the powder and granules from being locally lifted upward, and the supply air is dispersed to raise the powder and granules layer upward with a uniform pressure. Since it tends to permeate toward the surface, a good fluidized bed can be formed, and the particles of the granular material can be suspended without being biased in the surface direction of the aerated bed. The disordered through-holes mean that a large number of through-holes are not directional, and preferably the through-holes have branches and communicate with each other. As a result, it is possible to easily form a fluidized bed in which the powder and granular material formed in the fluidized portion of the powder and granular material coating treatment tank is uniformly suspended without causing deviation of the particle diameter in the surface direction of the aerated bed. Therefore, when the powder or granular material is attached to the surface of the object to be processed to cover the surface of the object to be processed, it is possible to evenly adhere the particle to the object to be processed. The air permeability of the aeration body is 5 to 1
It is about 0 Nm ³ / m ³ / s, and the through hole has a diameter of 60-
It is preferably 100 μm. Furthermore, it is even better if the ventilator has a thickness of 0.5 to 3 mm. [Second Characteristic Configuration and Operation and Effect] As a second characteristic configuration of the fluid tank for coating powder and granular material of the present invention, the powder and granular material in the first characteristic configuration is stucco which is refractory particles for forming a precision mold. When the material to be processed in the first characteristic configuration is used as a model for forming a precision mold in precision mold making (corresponding to claim 2), sand having a high particle density such as zircon sand is used as a material. Even when used as stucco material, powder particles (zircon sand) can be suspended evenly, and the model is inserted into the suspended powder particles to accurately measure the stucco particles that adhere to the surface of the model. It becomes possible to adhere well. As a result, by immersing the model in the fluidized bed of stucco material, a layer of stucco particles can be accurately formed on the model surface, and a good shell mold can be formed. [Third Characteristic Configuration and Action and Effect] As a third characteristic configuration of the fluid tank for coating particles according to the present invention, a felt is used as a vent in the second characteristic configuration (corresponding to claim 3). If so, the felt is formed by compressing wool or the like, and thus the felt is a porous body,
The through holes are randomly formed, and the felt is appropriately compacted, and the air permeability thereof is appropriately low.
If the thickness is sufficient, it has good characteristics as a fluid bed ventilator. That is, the through hole has a path that draws a complicated curve, branches, and communicates with another through hole. Therefore, when the pressure of the charge air is applied below the felt, the charge air flow passing through the felt is induced by the through holes in the felt, resulting in effective pressure loss, diffusion in the felt, and the lower charge. At the same time as suppressing the influence of the direction of the air flow, the air supply after passing through the felt is dispersed and uniformly supplied to the fluidized bed of the upper stucco material. As a result, the static pressure is applied while avoiding the effect of the dynamic pressure below the aeration bed, so that the fluidized bed is supplied with the supply air that generates a uniform pressure from the upper surface of the aeration bed. Therefore, in the fluidized bed, the stucco particles are well dispersed while floating, and the stucco particles can be evenly and accurately adhered to the surface of the model to be dipped. It should be noted that the felt preferably has a bulk density of about 0.25 to 0.4 g / cm ^3, although it depends on the degree of compaction, for example, if the air permeability is about 15 to ³⁰ Nm ³ / m ³ / s. The thickness is preferably 1 to 10 mm, and more preferably 3 to 5 mm. When the bulk density is less than 0.25 g / cm ³ , the opening diameter of the through hole becomes large, and the air permeability is inevitably large, so that the dynamic pressure or the pressure distribution below the aeration bed exerts the action above the aeration bed. If the bulk density is larger than 0.4 g / cm ³ , the opening of the through holes will be excessively large because the felt thickness required to prevent it will be extremely large, and the structure of the aerated floor tends to be complicated. As a result of the smaller diameter, lower air permeability, and higher pressure loss, the pressure in the pressure chamber must be increased, and it becomes necessary to increase the pressure resistance of the pressure chamber and the aeration bed. Both of them are not preferable because they result in complicated results. Its thickness can be determined in relation to the bulk specific gravity. [Fourth Characteristic Configuration and Operation and Effect] As the fourth characteristic configuration of the fluid tank for coating powder and granular material of the present invention, the gas supply means in the second characteristic configuration or the third characteristic configuration is provided below the aeration bed. It is further preferable that the gas supply pipe is arranged in a direction along the lower surface of the ventilation floor and has a plurality of air supply holes that open downward (corresponding to claim 4). With this configuration, the dynamic pressure of the air supply from the gas supply means acts only on the floor surface of the pressurizing chamber, and does not act on the lower surface of the ventilating floor. Therefore, since only the static pressure of uniform air supply acts on the lower surface of the ventilation floor, it passes along the through holes of the ventilation floor from the lower surface to the upper surface of the ventilation floor. Therefore, the air supply from the upper surface of the ventilated floor creates uniform pressure. It will be supplied to the fluidized bed of stucco material formed above the ventilation floor. As a result, the effects of the second characteristic configuration or the third characteristic configuration can be ensured.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As an embodiment of the fluidized bed for coating powder and granular material of the present invention, an example of a precision casting mold fluidizing tank will be described below with reference to the drawings. FIG.
(A) shows a precision casting mold forming fluidizing tank used for adhering stucco grains 9A to the model 6A to form a shell mold by using the fluidizing container for coating powder particles according to the present invention.
The fluid tank F is provided with an air supply unit 7 at the lower portion of a cylindrical container 1 having an open upper end, and the air supply unit 7 is provided at the upper end of the air supply unit 7.
A ventilation floor 2 for partitioning the above and the upper fluidized section 10 is provided, and the air supply section 7 is provided with a gas supply means 4 and is formed in an airtight pressurizing chamber 7A. The gas supply means 4 is equipped with a gas supply pipe 5 which is airtightly inserted from the side wall of the pressurizing chamber 7 </ b> A and arranged along the ventilation floor 2.
The gas is supplied into the pressurizing chamber 7A from a plurality of air supply holes 5a provided below. The air supply hole 5a is provided so as to be directed obliquely downward to the left and right in a sectional view, as shown in the axial cut surface in FIG. 1B, and the gas supplied from the air supply hole 5a (hereinafter, referred to as air supply) is left and right. Then, the airflow collides with the bottom of the pressurizing chamber 7A, the kinetic energy is absorbed, and the interior of the pressurizing chamber 7A is pressurized by static pressure. The ventilation floor 2 includes a porous ventilation body 3 and the ventilation body 3
Lower support 2b consisting of a coarse wire mesh 13 for supporting the lower part
In order to prevent the ventilation body 3 from rising due to air supply from below, and to prevent the particles of the stucco material 9A, which is the powdery or granular material 9 charged upward, from falling onto the ventilation body 3,
The upper support 2a is composed of a fine wire mesh 12. The ventilation body 3 is formed of one sheet of felt.
This felt 3 has a thickness of 3 mm and a bulk density of 0.3 g / c.
intended m ^3, the air permeability is 20Nm ³ / m ³ / s. The felt has through-holes 3a uniformly throughout, and the through-holes 3a are formed randomly because of the gaps between the fibers filled with the felt 3. That is, the through hole 3a communicates with the upper and lower surfaces of the felt 3, forms a meandering path in the felt 3, and further communicates with other through holes 3a communicating with the upper and lower surfaces of the felt 3. Therefore, the supply air flowing from the lower surface of the felt 3 into the felt 3 through the through holes 3a rises while changing the direction along the through holes 3a, at the same time, diffuses and flows into the flow section 10 from the upper surface of the felt 3. become. Therefore, the supply air passing through the felt 3 is
The pressure is equalized while passing through the felt 3. Furthermore, since the opening of the through hole 3a on the upper surface of the felt 3 is enlarged, the outflowing air diffuses out. As it changes direction and rises as above, the flow resistance increases and therefore
The pressure loss of the supply air passing through the felt 3 increases. As a result, the supply air passing through the felt 3 by the pressure of the supply air applied to the lower surface of the felt 3 flows from the upper surface of the felt 3 to the flow part 10
It is sufficiently dispersed and diffusely supplied.

The fluidized tank F shown in FIG.
A stucco material 9A made of zircon sand is charged in the fluidized portion 10 above the. And the inserted stucco material 9
The layer A is fluidized by the air flow passing through the aerated bed 2 and rising to form the fluidized bed 11. As mentioned above, since the air supply is diffusely supplied from the felt 3,
A uniform pressure is generated below the lower surface of the layer of stucco material 9A so that the supply air uniformly rises through the gaps between the grains of stucco material 9A to float the stucco material 9A and form the fluidized bed 11.

A system using the above-described precision mold forming fluid tank F
The method for forming the mold is shown in Fig. 2.
Then, the zircon sand 9A is charged into the fluidizing portion 10 of the fluidizing tank F.
Aside from the gas supply pipe 5 of the lower air supply unit 7, the pressure is 5 to 1
Supplying 0 MPa air to fluidize the zircon sand 9A
The fluidized bed 11 is formed. From the gas supply pipe 5
The supply pressure was set to 5 to 10 MPa because the thickness was 3 mm,
Bulk density 0.3g / cm ^ThreeAnd the air permeability is 20 Nm^Three/ M^Three/
It corresponds to the use of felt 3 of s
The pressure applied from below the layer 11 is 7 to 15 MPa,
Air supply is well dispersed, and 9 stucco materials are in good floating condition.
A favorable fluidized bed is formed. Preformed in a thermostatic chamber
Dip the wax model 6A into the investment slurry,
The investment slurry is dried on the wax model 6A.
In the meantime, as shown in FIG. 2 (a) → (b), the fluidized bed 1
1 into the fluidized bed 11 from the surface. The inserted b
3) On the surface of the model 6A, as shown in FIG.
Zircon sand 9A particles floating in the surrounding space are wax model 6A
It adheres to the investment slurry film on the surface of. Jill
When the Kon sand 9A adheres, as shown in FIG.
The model 6A is pulled up from the fluidized bed 11. One-time insert operation
Then, since the 9A layer of zircon sand does not have a sufficient thickness,
The wax model 6A after the 9A particles of zircon sand were adhered again to the fluidized bed 1
Insert zircon sand 9A by repeating insertion operation in 1
The wax coated with the adhesion layer 8 as shown in FIG.
Obtain the model 6A. In addition, the above stucco material such as zircon sand
The operation of attaching to the wax model is called sanding.
Stucco wood in the early stages of repeated sanding
The particle size of is preferably small, 100-300 μm
It is preferable that the size is about the same, and skin sand with this size is used.
By doing so, the casting surface can be improved, so a wax model
Cover the part in contact with a fine refractory, and then sand
The stucco material used for is a coarse refractory and a fine refractory
Reinforce layers of objects. This coarse refractory will pass through in a precision mold.
It also improves the temper and is 300-1000 μm.
Something is preferable. In this way, the wax model
It is covered with taco material to form a precision mold.
After drying the slurry, dewaxing and precision casting
To serve.

Next, another embodiment of the present invention will be described. <1> In the above-described embodiment, an example in which the object 6 to be processed is the wax model 6A used for precision casting and the stucco material 9A is attached as the powder 9 has been described. The fluidized tank is not limited to this application, but can be suitably used for a treatment for adhering powdery or granular material onto a solid surface such as powder coating. For example, Teflon powder, which is a kind of heat-sealing paint, is loaded on the aeration bed 2 as the granular material 9 to form the fluidized bed 11, and the appropriately heated object 6 is suspended in Teflon powder. By dipping, it becomes easy to fuse Teflon to the surface of the object 6 to be processed. <2> In addition to the above, the fluidized tank of the present invention can also be used for classification of powder and granules. That is, as described above, since the air supply is non-directionally distributed from the fine holes and supplied to the fluidized bed 11, the air supply rises in the fluidized bed 11 in a uniform and dispersed state, so that the buoyancy causes the powder to flow. It is also possible to classify the granules. That is, the granular material having a wide particle size distribution is loaded on the aeration bed 2, and the air supply amount is gradually increased, and the upper layer portion of the fluidized bed is taken out at each increase of the air supply amount. The particle size corresponding to the rising linear velocity of the air supply (narrow particle size range)
Can be separated into powder and granules. This is because, as described above, the uneven distribution of the supply air is small, and the powdery particles can be suspended by the upward airflow of the supply air that rises at a uniform linear velocity over the entire upper surface of the fluidized bed 11. Is. <3> In the above-described embodiment, the gas supply pipe 5 is provided as the gas supply means 4 along the aerated floor 2, and the gas supply pipe 5 is provided.
Although an example in which a plurality of air supply holes 5a opening downward are provided in the above, the gas supply means 4 may be any one as long as it does not generate an air flow that exerts a dynamic pressure on the lower surface of the ventilation body 3,
Therefore, the position and opening direction of the air supply hole 5a are not limited to those described in the above embodiment. Further, even if a gas-permeable partition wall that divides the air supply unit 7 into upper and lower parts is provided and an air supply pipe is provided below the partition wall, the air supply pipe may be indirectly arranged with respect to the ventilation floor 2. Well, the gas supply pipe 5 is opened in the wall of the air supply part, and a porous body is provided in the opening so that the air supply is dispersed and the air flow distributes the total pressure on the lower surface of the ventilation body 3. It does not have to occur. <4> The upper and lower supports 2a and 2b of the ventilation floor do not have to be the wire nets 12 and 13, and the upper support 2a moves upwards of the ventilation body 3 against the pressure of air supply from below. Any material can be used as long as it can prevent floating, and does not require strength as compared with the lower support body 2b, and the lower support body 2b has a weight relative to the weight of the granular material 9 filled above the aeration floor 2. , And the back pressure generated above the aeration floor 2 due to the ventilation resistance of the fluidized bed 11 formed by the filled powder and granules 9, both the upper and lower supports 2a and 2b are in a grid shape. It may be a body or a parallel body as long as it has the strength satisfying the above requirements. <5> In the above embodiment, the ventilation member 3 has a thickness of 3
mm, bulk density 0.3 g / cm ³ , air permeability 20 Nm ³ /
The one composed of one felt of m ³ / s is shown,
The number of felts is not limited to one, and the thickness, bulk specific gravity, and air permeability are not limited to the above specifications, and if the flow resistance to the required air supply and the diffusion of the air supply can be achieved. Of course, the material of the ventilation body 3 is not limited to felt, but may be synthetic resin, sintered metal, or the like as long as it is a porous body and satisfies the above requirements. <6> In the above-described embodiment, an example of using zircon sand as the stucco material 9A forming the shell mold is shown, but casting sand such as olivine sand and silica sand, ceramic powder, and the like can also be used. Further, it is applicable not only to the shell mold but also to the solid mold. <7> In the above embodiment, the pressure of the gas supplied from the gas supply pipe 5 is set to 5 to 10 MPa, but this pressure affects the ventilation characteristics of the ventilation body 3 and the fluidized bed 11 and the fluidization characteristics of the fluidized bed 11. However, it is not limited to 5 to 10 MPa. <8> In the above embodiment, it is preferable that the grain size of the stucco material in the initial stage is about 100 to 300 μm and the grain size of the stucco material used for the subsequent stucco is about 300 to 1000 μm. It is preferable to change it appropriately according to the metal, and the particle size of the stucco material is not limited to the above range.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view showing an example of a fluid tank for coating powder and granules of the present invention.

FIG. 2 is an explanatory view of the use of a precision casting mold flow tank as an application example of the present invention.

FIG. 3 is an explanatory view of the coating operation of the fluid tank for coating powder and granular material of the present invention.

FIG. 4 is an explanatory view of a conventional precision casting mold flow tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Aeration floor 3 Aeration body 3a Through hole inside a ventilation body 4 Gas supply means 5 Gas supply pipe 5a Air supply hole 6 Object to be treated 6A Model 7A Pressurization chamber 9 Powder granules 9A Stucco material

Claims (4)

[Claims] 1. An aeration bed (2) below a container (1), and a gas supply means (4) for supplying a gas from below the aeration bed (2), the object to be treated by the supplied gas. (6) The granular material (9) to be adhered to the surface to be coated is fluidized, and the article to be treated (6) is immersed in the fluidized granular material to form the article to be treated (6). A fluid tank for coating a powder or granules to which the powder or granules (9) are attached to, wherein the ventilating bed (2) has random through holes (3a) uniformly over its entire surface ( 3), an airtight pressurizing chamber (7A) is formed below the ventilation body (3), and the gas supply means (4) is provided in the pressurizing chamber (7A) to supply the gas. A fluid tank for coating powder and granules, wherein a pressurized space is formed below the aerated floor (2). 2. A method for use in precision mold making, wherein the granular material (9) is used as a stucco material (9A) for forming a precision mold, and the object (6) is used as a model (6A) for forming a precision mold. Item 2. A fluidized tank for coating powder or granules according to item 1. 3. The fluid tank for coating powder particles according to claim 2, wherein a felt is used as the ventilation body (3). 4. A plurality of air supply holes arranged in the gas supply means (4) below the ventilation floor (2) in a direction along the lower surface of the ventilation floor (2) and opening downward. (5
The fluid tank for powder-particle coating treatment according to claim 2 or 3, wherein a gas supply pipe (5) having a) is provided.