JP2574918Y2 - Sprayer of centrifugal sprayer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray plate of a centrifugal sprayer in a spray drying apparatus for ceramic slurry.

[0002]

2. Description of the Related Art As a conventional spraying pan, an annular wall 13 is formed on the peripheral portion of a lower disk 11 and an upper disk 12 as shown in FIG.
There was something with.

As shown in FIG. 4, a centrifugal spraying device using this spraying disc drives a rotary shaft 42 on which the spraying disc 1 is attached by 3000 to 200 by a motor 41 installed above.
The stock solution supplied to the spray board 1 from the stock solution supply pipe 43 is rotated by a centrifugal force at a high speed of 00 rpm.
5 is sprayed as droplets. The droplets sprayed at this time are instantaneously dried by the hot air sent from the hot air inlet 44 to the spray drying chamber 45, fall into spherical powders and fall, and are taken out from the product take-out port 46. Here, the size of the droplet to be sprayed is determined by the diameter of the spraying board 1, the number of rotations, the slurry concentration, the sending flow rate, and the like. On the other hand, the exhaust gas passes through an exhaust pipe 48, and the powder and granules are separated and collected by a cyclone 47 and discharged. Thus, a granulated body of the ceramic raw material can be obtained.

[0004]

However, in the case of spraying with the conventional spraying board 10 shown in FIG. 5, the stock solution injected from the inlet 16 flows on the plane of the lower disk 11 and, as shown in FIG. When the flow reaches the spray hole 15 formed in the vertical direction, the flow changes in the vertical direction rather than the horizontal flow, and the passing distance E of the undiluted liquid film G is long above the spray hole 15 and the passing distance D is short below the spray hole 15. become. For this reason, the undiluted liquid film G is thicker under the spray hole 15, and the undiluted liquid film G is extended and thinned toward the upper side of the spray hole 15. The droplets sprayed from the upper side have a large particle diameter, and the particle diameters of the droplets sprayed from the upper side are small.

[0005] In addition, coarse particles having a particle size larger than the finally required particle size of the dried powder particles are cut by a mesh and become useless. Reduce the stock solution throughput or spray
However, as a result of these methods, when the amount of the undiluted solution is reduced, coarse particles are slightly reduced, but productivity is remarkably reduced. When the number of rotations is increased, some of the sprayed droplets adhere to the inner wall of the spray-drying chamber 45 before being dried. Will decrease the performance.

During the rotation of the spray disk 10, a part of the undiluted liquid film G flowing on the lower disk 11 scatters toward the upper disk 12 and adheres to the inner wall surface 12a of the upper disk 12. There is a possibility that the weight balance of the board 10 may be lost and the rotation balance may be disturbed, which in turn promotes wear of the bearing portion. Therefore, there is a problem that the wear of the sprayer is accelerated, and the particle size distribution of the product taken out is unnecessarily biased.

[0007]

In view of the above problems, in the present invention, the upper disk is formed in an inverted cup shape, the lower disk is formed in a hollow shape, and an annular wall is formed on the peripheral portion formed by the upper disk and the lower disk. A spray plate of a centrifugal sprayer provided with a spray hole having an outlet portion inclined downward in the annular wall.

[0008]

The undiluted solution injected into the spray disk of the present invention flows down as a liquid film on the inner wall surface of the upper disk in the shape of an inverted cup, and the liquid film is formed by the inclination of the upper disk and the rotation of the spray disk. Is extended, so that when reaching the annular wall, a liquid film having a uniform thickness can be obtained. Further, the liquid film reaching the annular wall is supplied to the spray hole, and atomized into the spray drying chamber through the side wall of the spray hole and sprayed, but the spray hole outlet of the annular wall is inclined. Therefore, the passage distance of the liquid film passing through the spray hole can be made substantially the same. For this reason, the particle size variation of the sprayed droplets can be considerably reduced, and the particle size distribution of the dried powder can be narrowed. The product obtained as described above becomes a fine powder and granules which can be easily subjected to pressure molding.

In addition, since the lower disk has a hollow shape, the spray disk can be easily cleaned.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the illustrated embodiments, but the present invention is not limited to these embodiments.

FIG. 1 is a partially cutaway side view of the spray pan 1 of the present invention. The spraying disc 1 has an inverted cup-shaped upper disc 2 having an injection port 6 for undiluted solution at the upper part, and a hollow disc-shaped lower disc 4 on the peripheral edge thereof and an annular wall provided on the peripheral edge of the lower disc 4. 3 is formed. Further, a plurality of oblong spray holes 5 are provided in the annular wall 3, and as shown in FIG.
Inclination downward outlet portion 5a with respect to the rotation axis direction of the theta ₁
Is inclined at 2 ° to 45 °, preferably 2 ° to 30 °.

The length L of the spray holes 5 at the peripheral edge of the lower disk 4 may be 5 mm or more, and the height H of the spray holes 5 is 10 to 50% of the radius R of the spray plate 1. desirable. The shape of the spray hole 5 is such that the upper and lower portions have a radius of curvature r of 3 to 10.
It is desirable to have a long hole shape configured in a curved portion of mm,
The height H and the length L of the spray hole 5 are formed with a mutual correlation.

Next, the operation of the centrifugal spray-drying apparatus using the spray board 1 of the present invention will be described. As shown in FIG.
First, the stock solution supplied from the stock solution supply pipe 43 to the spray board 1 of the present invention is sprayed as droplets from the spray holes 5 of the spray board 1 into the spray drying chamber 45 via the liquid distributor, and spray-dried from the hot air inlet 44. It is instantaneously dried by the hot air sent to the chamber 45, falls into a spherical powder and granules, and falls into a product outlet 46.
Taken out of On the other hand, the exhaust gas passes through an exhaust pipe 48 to separate and collect the powder and granules by a cyclone 47, and is discharged.

At this time, the undiluted solution supplied from the upper injection port 6 flows on the inner wall surface 2a of the upper disk 2 as a liquid film. However, due to the rotational force of the spray disk 1 and the inclination of the upper disk 2, When the fluid flows down while being stretched and reaches the annular wall 3, a liquid film having a uniform thickness is obtained. That is, since a liquid film having a uniform thickness can be supplied into the spray hole 5, the particle diameter of the sprayed droplet can be made uniform.
Further, the undiluted liquid film G reaching the annular wall 3 changes in the vertical direction only after reaching the annular wall 3 as shown in FIG. That is, the undiluted liquid film G reaching the annular wall 3 is further extended and sprayed through the side wall of the spray hole 5, so that the sprayed droplets are atomized. In addition, since the degree of variation in the particle diameter of the sprayed droplet is greatly affected by the passing distance in the spray hole 5, the outlet portion 5a of the spray hole 5 is directed downward by 2 ° to 45 ° with respect to the rotation axis direction, By providing the inclination angle θ ₁ of preferably 2 ° to 30 °, the passing distance (A, B, C) of the liquid film from the inlet 5b to the outlet 5a of the spray hole 5 can be made substantially the same. it can. Therefore, the droplets sprayed along the upper side of the spray hole 5 and the droplets flowing downward and sprayed can be made substantially the same in size, and the particle size variation of the sprayed droplets can be reduced. The dry powder obtained as described above is a granulated product having a small particle size distribution.

In the case where the rotation speed is lowered to stop, the spray disk of the present invention is provided with the lower disk 4, so that the droplets above the spray holes 5 drop due to the reduction of the rotation speed. At the same time, it is possible to prevent adhesion to the obtained dried powder and granules, and at the same time, in the sprayer of the present invention, the injected stock solution film G flows along the inner wall surface 2a of the upper disk 2, The liquid film does not adhere to the inner wall surface 2a. As a result, there is no fear of disturbing the rotational balance of the spray board 1, and wear of the bearing portion can be prevented. Also, it is possible to prevent the particle size distribution from being biased due to the variation in rotation. Since the lower disk 4 has a hollow shape, cleaning after use can be easily performed.

In the spray pan 1 of the present invention, the outlet 5a of the spray hole 5 of the annular wall 3 is inclined downward with respect to the rotation direction, but the outlet 5a of the spray hole 5 has a certain radius of curvature. May be formed into a curved surface.
Any shape may be used as long as the passage distance from b to the outlet 5a can be made equal. Further, as shown in FIG. 3, the inclination angle θ ₂ of the annular wall 3 with respect to the horizontal direction is 2 ° with respect to the horizontal direction.
The same effect can be obtained by inclining downward at an angle of up to 45 °, preferably 2 ° to 30 °.

Although the spray disk 1 of the present invention is formed integrally, the upper disk, the lower disk, and the annular wall are formed separately.
An assembled type may be used, and in that case, it may be performed with screws or bolts.

Further, the spray plate 1 of the present invention can be used not only as a slurry for ceramics but also as a spray plate for a spray-drying device for a stock solution such as a medicine or food.

EXPERIMENTAL EXAMPLE As stock solution G, specific gravity 1.6 containing alumina at 60% by weight,
A spray experiment was performed using a slurry having a viscosity of 30 centipoise. As a spray machine 1 of the present invention, 100mm diameter in the shape shown in FIG. 1, the inclination angle theta ₁ of the outlet portion 5a of the spray hole 5 10
The liquid film of the slurry was spray-dried under the same conditions using a conventional spraying board shown in FIG. 5 as a comparative example, and the particle size distribution of the dried granules was compared. As shown in Table 1 and FIG. 7, by using the sprayer 1 of the present invention, it is possible to obtain a powder having a narrow particle size distribution, that is, a uniform particle size.

The particle size in Table 1 was measured with a sieve shaker.
This is a value obtained by setting the values to 45, 76, 94, and 130 μm.

[0021]

[Table 1]

In the same manner as above, an experiment was conducted by changing the inclination angle θ ₁ of the outlet 5a of the spray hole 5 to 2 °, 10 °, and 30 °. The results are shown in Table 2 and FIG.

[0023]

[Table 2]

It can be understood from the above that the inclination angle θ ₁ of the outlet 5 a of the spray hole 5 depends on the state of the slurry.
Is smaller than 2 °, the passage distance in the spray hole 5 shown in FIG. 2 is A <B <C, and the effect of narrowing the particle size distribution of the dried powder is poor. If the inclination angle θ ₁ is set to be larger than 45 °, the passing distance of the stock solution G in the spray hole 5 becomes A> B
> C, and conversely, the particle size distribution of the dried powder became wide.
Therefore, the inclination angle theta ₁ of the outlet portion 5a 2 ° to 45 °, preferably it can be seen that it is sufficient with 2 ° to 30 °.

The maximum value of the inclination angle θ ₁ is determined by the relationship between the length L, the height H, etc. of the spray hole 5. For normal use, θ ₁ is set within the above range. It should be left.

[0026]

As described above, the spray disk according to the present invention has an upper disk formed in an inverted cup shape, and an annular wall having a plurality of elongated hole-shaped spray holes is provided on a peripheral portion of the inverted disk-shaped upper disk. In addition, since the spray hole outlet of the annular wall is inclined downward, the variation in the particle diameter of the spray droplets can be reduced, so that the particle size distribution of the spray-dried powder can be narrowed. Therefore,
Reduce the amount of coarse particles contained in the dried stock solution, reduce waste of the stock solution, and obtain powders and granules that can be easily pressed, and obtain high-quality granules with uniform particle size. Can be. In addition, since the upper disk has an inverted cup shape, it is possible to prevent the liquid film from sticking, so that there is no danger of disturbing the rotation balance of the spray disk, it is possible to prevent wear of the bearing portion, and a particle size distribution due to rotation variations. It can also prevent bias. And
Since the lower disk is hollow, cleaning after use can be easily performed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing a spray board of a centrifugal spray apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a portion X in FIG. 1;

FIG. 3 is a partially cutaway side view showing another embodiment of the present invention.

FIG. 4 is a schematic diagram showing a centrifugal spray device.

FIG. 5 is a partially cutaway side view showing a spray plate of a conventional centrifugal spray device.

FIG. 6 is a sectional view showing a Y part in FIG. 5;

FIG. 7 is a graph comparing the particle size distributions of the granules after spray drying in the spray board of the present invention and the conventional spray board.

FIG. 8 is a graph showing the particle size distribution of the powder after spray drying when the inclination angle of the spray board of the embodiment of the present invention is changed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Spraying board 2 ... Upper disk 3 ... Annular wall 4 ... Lower disk 5 ... Spray hole 5a ... Outlet 6 ... Stock solution inlet 41 ... Motor 42 ... Rotating shaft 43 ... Stock solution supply pipe 44 ... Hot air inlet 45 ... Spray drying chamber 46: Product outlet 47: Cyclone 48: Exhaust pipe

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B05B 3/00-3/18 B01D 1/18-1/20

Claims (1)

(57) [Scope of request for utility model registration] 1. A spray disk of a centrifugal sprayer in a spray-drying apparatus, comprising an inverted cup-shaped upper disk and a hollow lower disk, and a ring formed between the upper disk and the lower disk. A spray plate for a centrifugal sprayer, wherein a spray hole is provided on a wall, the outlet portion of which is inclined downward.