JP2579312Y2 - Sprayer for centrifugal spray equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sprayer for a centrifugal sprayer in a spray-drying apparatus for slurry of a stock solution of a drug, foodstuffs, and ceramics.

[0002]

2. Description of the Related Art FIG. 8 is a schematic view of an embodiment of a centrifugal spray-drying apparatus. As shown in FIG. 8, a stock solution G such as a ceramic slurry supplied from a stock solution supply pipe 8 is rotated by a rotating shaft 4 at a high speed. And sprayed into the spray drying chamber 10 as fine particles from the spray board 9, dried by hot air sent from the hot air inlet 11 to the spray drying chamber 10, dropped into powder and granules, and taken out of the product It is taken out of the mouth 12. On the other hand, the exhaust gas passes through an exhaust pipe 13 to separate and collect the powder and granules by a cyclone 14, and is discharged.

[0003] Conventionally, as this kind of spraying board 9, it is generally known that an annular wall 3 is provided on the periphery of upper and lower disks 1, 2 as shown in FIG. I have. In addition, a Kessner type sprayer 9 'having a structure as shown in FIG. 7 is also known (see Japanese Utility Model Publication No. 61-10767, Japanese Utility Model Application Laid-Open No. 62-179052, etc.).

[0004]

2. Description of the Related Art A conventional spray plate 9 as shown in FIG.
In the case of centrifugal spraying, the undiluted solution G flows outward in the form of a liquid film on the plane of the lower disk 2, spreads vertically from the plane when reaching the spray hole 5, and is sprayed from the tip. Become.

However, since the shape of the spray holes 5 in the conventional spray board 9 is rectangular as shown in FIG. 6, the liquid film of the raw material G does not easily spread in the vertical direction during spraying. For this reason, the state of the liquid film of the stock solution G at the time of spraying becomes thinner as the lower side becomes thicker and upper, and the droplets sprayed from the lower side are large and the droplets sprayed from the upper side are small. As a result, there has been a problem that the dispersion of the particle diameter after drying the sprayed droplets by a dryer such as a spray dryer becomes large.

[0006] Among the obtained dry particles, coarse particles having a particle diameter larger than the finally required particle diameter are cut by a sieve mesh, resulting in a raw material loss. Therefore, as means for reducing the coarse particles, there are means such as reducing the stock solution processing amount or increasing the number of revolutions of the spraying plate 9. As a result, although the coarse particles are slightly reduced, the productivity is remarkably reduced. However, there has been a problem that the spraying device is deteriorated, and the spraying device is quickly worn out, and the particle distribution is increased more than necessary.

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a spray disk having a plurality of spray holes along the periphery of an upper and lower disk. It has a long hole shape consisting of short sides at both ends,
At least one of the short sides has an arc shape, the radius of curvature is 3 to 10 mm, and the length of the spray hole is 10 to 50% of the radius of the spray plate.

In the present invention, it is not necessary that all of the short sides forming the spray holes have a circular arc shape with the long sides, and at least one of the long sides has a smooth boundary. The shape may be a continuous arc.

[0009]

[Function] The undiluted solution introduced from the undiluted liquid supply port of the spraying disk flows as a liquid film along the lower disk by the rotation of the spraying disk, and reaches a vertical spray hole provided on the periphery of the lower disk to reach from the flat surface. It becomes a vertical change. At this time, in the spraying board of the present invention, at least one of the short sides of the spray holes has an arc shape that is continuous with the long side, so that a uniform liquid film is supplied to the entire surface of the vertical spray holes, Sprayed outward. Therefore, variation in the particle size of the sprayed fine droplets is small, and the particle size distribution of the dried particles can be narrowed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below based on the illustrated embodiment (the same parts as in the prior art are denoted by the same reference numerals).
However, the present invention is not limited to these embodiments.

FIG. 8 shows a schematic diagram of one embodiment of a centrifugal spray drying apparatus. As shown in FIG.
Is sent to a spraying plate 9 which rotates at high speed by the rotating shaft 4, is sprayed as fine particles from the spraying plate 9 into the spray drying chamber 10, and is dried by hot air sent from the hot air inlet 11 to the spray drying chamber 10. The powder falls as powder and is taken out from the product take-out port 12. On the other hand, the exhaust pipe 13
The powder is separated by the cyclone 14 and collected and discharged.

As shown in FIG. 1, the spray disk 9 comprises an upper disk 1, a lower disk 2 and an annular wall 3 at the peripheral edge thereof. A plurality of spray holes 5 are formed in the annular wall 3. When spraying is performed using the spray disk 9, the undiluted solution G supplied from the upper part flows outward in the form of a liquid film on the flat surface of the lower disk 2, and when it reaches the spray hole 5, the liquid does not move vertically. Spread in the direction
It will be sprayed from the tip.

FIG. 2 is an enlarged view of the spray hole 5, as shown in FIG. 2. The spray hole 5 is a long hole formed by two short upper and lower short sides 5a and an intermediate long side 5b. is there. According to the spray board 9 of the present invention, the short side portion 5 of the spray hole 5 is formed.
Since a is a guide shape continuing to the long side portion 5b, FIG.
As shown in (1), the raw material G is easily transmitted from the short side portion 5a to the long side portion 5b at the time of spraying, and the spread in the vertical direction can be increased to perform uniform spraying.

The radius of curvature R of the arc-shaped short side portion 5a starting from the center line of the spray hole 5 is 3 to 10 m.
m and １ ／ or less of the length H of the spray hole 5. This is because, when the radius of curvature R is smaller than 3 mm, the undiluted solution G does not flow to the upper side of the spray hole 5 as shown in FIG. 3 showing the spray hole 5 having the arc-shaped short sides 5a having various curvature radii R. Cannot be sprayed uniformly, while the radius of curvature R is 10 m
If it is larger than m, the liquid film of the raw material G will reach the upper arc portion, and uniform spraying will no longer be possible.

In this embodiment, the undiluted solution G is the lower disc 2
Although the case of flowing above is shown, since it may flow below the upper disk 2 depending on the shape of the spray disk 9, the short side portion 5a on the upper side of the spray hole 5 also has the same radius of curvature R. It is desirable to make it into an arc shape. Further, in this embodiment, since the spray holes 5 have a symmetrical shape, the rotation direction of the spray board 9 may be any direction.

Next, another embodiment of the shape of the spray hole 5 will be described. In FIG. 4, the short side portion 5a on the lower end side of the spray hole 5 has an arc-shaped guide shape that is continuous only with one long side portion 5b. That is, when the rotation direction of the spray disk 9 is determined and the undiluted solution G flows only on the lower disk 2, only one portion may be formed in an arc shape.

Further, in these embodiments, the sectional shape of the annular wall 3 at the peripheral portion of the lower disk 2 is not particularly limited, and may be rectangular or trapezoidal as shown in FIG. The width W of the annular wall 3 may be at least 5 mm. Further, the length H of the spray hole 5 is preferably 10 to 50% with respect to the radius of the spray board 9.

Experimental Example A spray plate 9 of the present invention shown in FIG. 1 was experimentally manufactured, and a spray test of ceramic raw material powder was performed by changing the radius of curvature R of the short side portion 5a of the spray hole 5 in various ways.

As a stock solution, a slurry containing 60% by weight of alumina and having a specific gravity of 1.6 and a viscosity of 30 centipoise was used.
Further, as the spraying board 9, a thing having a diameter of 100 mm is prepared, and the slurry is spray-dried under the same conditions using the spraying boards 9 having different curvature radii R of the short side portions 5 a of the spray holes 5, and the dried particles are dried. The particle size distribution was compared.

As shown in FIG. 9, when the radius of curvature R of the short side portion 5a is smaller than 3 mm, the state of the liquid film flowing through the spray hole 5 becomes thinner as the upper side becomes thicker while the lower side becomes thicker. The effect of narrowing the particle size distribution of the dried particles was poor. Conversely, when the radius of curvature R is larger than 10 mm, the state of the liquid film flowing through the spray holes 5 becomes thicker on the upper side, and the particle size distribution of the dried particles tends to be broader. On the other hand, when the radius of curvature R of the short side portion 5a was 3 to 10 mm, the particle size distribution of the dry particles was narrow, and it was found that dry particles having a uniform particle size could be obtained.

[0021]

As described above, according to the present invention, according to the present invention, in a sprayer having a plurality of spray holes along the periphery of the upper and lower disks, the shape of each spray hole is changed to a long side extending vertically and a short side at both ends thereof. It has a long hole shape composed of sides, and at least one of the short sides has an arc shape, and has a radius of curvature of 3 to 10 mm.
And the length of the spray hole is 1 to the radius of the spray board.
By setting it in the range of 0 to 50%, it is possible to reduce the variation in the particle size of the droplets to be sprayed, and to narrow the particle size distribution of the particles after spray drying. Therefore, it is possible to reduce the coarse diameter contained in the dried raw material, reduce waste of the raw material, and obtain a high-quality granulated material having a uniform particle diameter, particularly when used for spray drying of ceramic slurry. it can.
In addition, since the spray plate of the present invention can supply the undiluted solution as a thin liquid film, it is possible to reduce the number of rotations of the spray plate to obtain the same dry particle diameter by about 6% under the same amount of slurry treatment. Becomes

[Brief description of the drawings]

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

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a diagram illustrating a spray state of a liquid film from a spray hole by the spray board of the present invention.

FIG. 4 is a view showing another embodiment of the spray hole of the present invention.

FIGS. 5A and 5B are cross-sectional views showing various examples of a portion B in FIG. 1;

FIG. 6 is a partially broken side view showing a spray board of a conventional centrifugal spray apparatus.

FIG. 7 is a partially broken side view showing a spray plate of a conventional centrifugal spray device.

FIG. 8 is a schematic view of an embodiment of a centrifugal spray drying apparatus.

FIG. 9 is a graph showing the particle size distribution of dry particles after centrifugal spraying.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Upper disk 2 ... Lower disk 3 ... Annular wall 4 ... Rotary axis 5 ... Spray hole 5a ... Short side part 5b ... Long side part R ... Short side part Curvature radius 8 ・ ・ ・ raw liquid supply pipe 9 ・ ・ ・ sprayer 10 ・ ・ spray drying room 11 ・ ・ hot air inlet 12 ・ ・ product outlet 13 ・ ・ exhaust pipe 14 ・ ・ cyclone

Continuation of the front page (56) References JP-A-46-6686 (JP, A) JP-A-4-227081 (JP, A) JP-A-48-59410 (JP, U) JP-A-59-7756 (JP, A) , U) Actually open 50-52160 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B05B 3/00-3/18 B01D 1/20

Claims (1)

(57) [Scope of request for utility model registration] 1. A along the periphery of the upper and lower disks have a plurality of spray holes
In the spray machine that, long hole-like ungated consisting shorter sides of both ends with the long side portion extending shape above and below each spray hole, small
Both of the short sides are arc-shaped and the radius of curvature is 3 to
10 mm , and the length of the spray hole is
Spray Release of centrifugal spray device, characterized in that there in the range of 10-50% with respect to the radius.