JP2688836B2 - Filtration dryer - Google Patents

Description

The present invention relates to a filtration / drying apparatus, and more particularly to a nutsche type for filtering and drying a raw material slurry to extract solid particles in the raw material slurry in a dry powder state. Filter drying apparatus.

[Conventional technology]

The Nutsche-type filter dryer can perform many functions such as filtration, washing and drying with a single device and in a closed system, and safe handling of toxic substances, flammable substances, odorous substances, etc. It is widely used in the fields of food industry, pharmaceutical industry, chemical industry and the like because it has a feature that it can be carried out and its mechanism is relatively simple.

In addition, in these conventional filter drying devices, usually, in order to accelerate the drying, a function of stirring the filter cake, and the powdered solid product after drying is scraped to the discharge port provided in the lower bottom part. , Which has the function of discharging the rotor inside.

Then, regarding the configuration of these rotary blades and the discharge port,
In order to improve the processing efficiency, studies have been added from various aspects from the past, for example, the placement position, angle, and shape of each of the plurality of blades provided below the rotating arm have been devised to improve the stirring efficiency, Improving the transfer efficiency of solid products to the outlet provided in the center of the filtration surface (Japanese Patent Publication No. 57-5284)
No. 7, JP-A-57-56006, 61-21708), and an improved opening / closing mechanism of the discharge port provided in the central portion of the filtration surface (JP-A-58-10291, 60-102910), Many proposals have been made such as one in which a discharge port is provided from almost the center to the periphery of the filtration surface to increase the discharge speed of solid products (Japanese Patent Laid-Open No. 59-109215).

[Problems to be solved by the invention]

However, in the above-described conventional filter-drying device having a discharge port provided at the center of the filtering surface, the dry powder product can be taken out even if the structure of the rotary blade is improved. It is inherently unreasonable to centrifugely transfer powder that is subjected to centrifugal force by the rotation of the rotor blades to the central discharge port, so the time required for the discharge becomes longer and the residual amount after discharge There is a problem in that

Further, a filtration / drying device having a discharge port extending from substantially the central portion of the filtration surface to the peripheral portion (Japanese Patent Laid-Open No. 59-109215).
In the above, although it is effective in increasing the discharge speed, since the discharge port becomes a flat opening having a long side in the radial direction,
In order to make the discharge port and the closing valve difficult to process, and to close the discharge port having a flat opening tightly so that there is no fear of deterioration of filtration accuracy, an opening / closing means having a complicated structure is provided. It has the drawback of being necessary.

In view of the above problems, the present invention can surely stir the filter cake, yet the discharge of the dry powder is easy, and the remaining amount after discharge can be small, and the opening of the powder discharge port can be reduced. It is an object of the present invention to provide a filtration / drying device that does not have a restriction on the shape.

[Means for solving the problem]

In order to achieve the above-mentioned object, the filtration / drying apparatus of the present invention is formed in a bell-shaped housing and has a main body having a slurry supply port at the upper part, and a filter material and a filter plate which are supported in multiple layers and are provided at the lower opening of the main body. And, a lower lid having a filtrate discharge port and a powder discharge port, a rotary shaft vertically installed in the center of the main body for forward and reverse rotation, and a rotation for stirring and scraping attached to the lower end of the rotary shaft. In a filtration drying device equipped with wings,
The powder discharge port is provided with its inner opening located at the outer peripheral portion of the filter plate near the inner wall of the main body, and one blade surface with respect to the rotation direction of the rotary blade is a tilted flat surface whose lower end edge is the front. And the other blade surface is formed by a curved surface that draws a logarithmic spiral curve on the polar coordinates with the center of the rotation axis as a fixed point in its horizontal cross section or its approximate curved surface.

[Operation] In the present invention, a rotary blade for stirring and scraping is attached to the lower end of a rotary shaft that is vertically rotatably rotatable, and by this rotary blade, a filtering surface is provided in a drying step after the filtering step is completed. The powder layer deposited like a cake on top is agitated to accelerate its drying, and the dried powder is transferred to the powder discharge port and discharged. Since the blade surface of the blade has an inclined plane with the lower edge being forward, by rotating the rotary blade in the direction with this blade surface forward, the powder deposited on the filter surface by the inclined plane is formed. The layers can be scraped upwards and agitated.

The other blade surface with respect to the rotation direction has a curved surface that draws a logarithmic spiral curve on a polar coordinate whose fixed point is the center of the rotation axis in its horizontal cross section, or an approximate curved surface thereof, while the inner opening of the powder discharge port is a filter plate. Since it is provided at the outer peripheral portion, the powder after drying can be transferred to the outer peripheral portion where the powder discharge port is located by reversely rotating the rotary blade in the direction in which this blade surface is in the front direction. . At this time, the powder is not forced to perform an irrational movement against the centrifugal force received by the rotation of the rotary blade, but is also assisted by this centrifugal force, and the powder discharge port is efficiently moved along the curved surface of the rotary blade. Be transferred to.

Further, the powder discharge port may be provided by arranging the inner opening thereof on the outer peripheral portion of the filter plate near the inner wall of the main body, and the shape of the opening is not restricted. The opening shape most suitable for the closing and opening can be selected.

The above-mentioned logarithmic spiral curve is a curve obtained by the following formula on the plane polar coordinates with the center of the rotation axis as a fixed point.

r = a × exp (bθ) [where r is the distance from the fixed point,
θ is the argument, a is the initial value of the curve, and b is a constant. ] Also, the constant b in the above equation is determined so that μb <1 in relation to the static friction coefficient (μ) between the powder and the blade surface, and thus the logarithmic spiral obtained by the above equation is obtained. A curved surface that prevents the blade surface from adhering and co-rotating with the powder, and that the powder transfer amount at each radial position is constant, enabling smooth and rapid powder discharge. Can be

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. The configuration of the filtration / drying apparatus of the embodiments described below is an example, and the present invention is not limited to this.

FIG. 1 is a front sectional view showing a filtration drying apparatus of this embodiment, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is taken along line AA of FIG.
It is sectional drawing.

In FIG. 1 and FIG. 2, (1) is a main body, and the main body (1) is formed in a bell-shaped housing shape,
The lower lid (2) attached to the lower opening constitutes a closed pressure vessel. A slurry supply port (3), a pressurizing conduit (10) and an inspection hatch (11) are provided on the upper part of the main body (1), and a heating jacket (12) is provided on the outer peripheral portion thereof. .

Further, a rotary shaft (4) is vertically provided in the vertical direction at the center of the inside of the main body (1). The rotating shaft (4) is designed to be rotationally driven by a drive means (13) provided above the main body (1) in any forward and reverse directions, and a lower end portion thereof is provided with a pair of stirring members. -Rotating blades (5) for scraping are mounted symmetrically about the axis of rotation.

On the other hand, the lower lid (2) is configured to support the porous filter plate (6) and the filter cloth (7) in multiple layers with a predetermined gap therebetween, and also serves as a filtrate receiver. A filtrate discharge port (8) is provided, and a powder which is provided near the outer periphery of the lower portion and has an inner opening penetrating the outer periphery of the porous filter plate (6) and the coating (7) to communicate the inside and the outside. A body outlet (9) is provided.

In addition, the powder discharge port (9) has an inner opening that is a perfect circle, and inside thereof is provided with a closing valve (14) whose upper surface is located substantially flush with the upper surface of the coating (10) when closed. is there.

On the other hand, the rotor (5) is shown in FIG. 2 and A- in FIG.
As shown in FIG. 3 which is a sectional view taken along the line A, one blade surface S in the rotation direction is formed into a straight line in the radial direction and is formed into an inclined surface with its lower front edge facing forward, and Wing surface D
Is formed into a curved surface which is perpendicular to the vertical direction and which bulges forward by drawing a logarithmic spiral curve on the plane polar coordinates with the center of the rotation axis as the fixed point in the radial direction, and the upper and lower surfaces of which are parallel surfaces. It is supposed to have a shape.

And the logarithmic spiral curve of the blade surface D of the rotary blade (5) is
Each point on the curve on the plane polar coordinates with the center of the rotation axis as a fixed point is a curve obtained by the formula of r = a × exp (bθ) and occupying the angular coordinate position.

However, in the above equation, r is the distance from the fixed point, θ is the declination angle, a is the initial value of the curve, b is the relationship between the static friction coefficient (μ) between the powder and the blade surface, and μb <1. Is a constant determined as follows. In this logarithmic spiral curve, the tangent line at each point is
Since it has a constant angle with respect to the straight line connecting each point and the center of rotation, the blade surface d formed by this curve is
The contacting powder is always pushed in the outer peripheral direction at a constant angle and is transferred in the outer peripheral direction at a constant speed without causing adhesion or co-rotation. Since a part of the powder transferred in the outer peripheral direction is easily pressed against the inner wall of the main body (1) and adheres thereto, in the present embodiment, the powder adhered to the inner wall of the main body (1) is scraped off. The return blade (15) was attached to the outermost end of the blade surface D side.

With the filtration and drying apparatus of this embodiment having the above configuration,
The step of extracting the solid particles in the raw material slurry in a dry powder state will be described below.

First, after feeding and filling the raw material slurry into the main body (1) through the upper slurry supply port (3), pressure is applied by the pressure conduit (10) and the filtrate discharge system is depressurized to perform filtration. At this time, the filtrate that has passed through the filter cloth (7) on the porous filter plate (6) is collected at the filtrate discharge port (8) provided in the lower central portion of the lower lid (2) which also serves as a filtrate receiver, It is recovered outside the system through the filtrate outlet (8). On the other hand, the solid content in the raw material slurry is deposited as a wet cake layer on the surface of the filter cloth (7).

Then, from the upper pressure conduit (10) into the main body (1),
While sending the drying gas under pressure, the filtrate discharge system is depressurized,
While ventilating the drying gas, a heating jacket (12)
The solid content filtered by heating with is dried, but in this drying and filtering step, the rotary blade (5) is rotated clockwise as indicated by an arrow a in FIG. At this time, the solid content deposited in the form of a wet cake layer was collected by the rotor blade (5).
The blade is scraped up along the slope of the blade surface S, then falls at the rear end, is loosened into powder in the process of repetition, and the contact with the drying gas is increased to accelerate the drying. .

When the powder reaches a predetermined dry state, the feeding and heating of the drying gas are stopped and the rotary blade (5)
After stopping the rotation of the rotor, the closing valve (14) is lowered downward to open the powder discharge port (9), and the rotary blade (5) is rotated counterclockwise as shown by the arrow B in FIG. By rotating the blade surface D, the dried powder is transferred in the outer peripheral direction, sequentially dropped into the powder discharge port (9), and collected outside the system through the powder discharge port (9). .

In the filtration / drying apparatus of this embodiment, the powder can be transferred in the outer peripheral direction at a constant speed without adhering to the blade surface D or co-rotating, so that the powder can be transferred to a specific portion. The powder was not accumulated excessively, and it was possible to smoothly and quickly discharge the powder from the powder discharge port provided on the outer peripheral portion, and the remaining amount after the discharge could be made very small. On the other hand, it suffices if the powder discharge port is located at the outer peripheral portion and opened, and the shape of the opening can be selected to be suitable for ensuring the closing accuracy, and specifically, a perfect circular shape can be selected. It was possible to easily process both the opening portion and the closing valve, and the fitting accuracy of these could be easily increased to a level where there was no need to worry about deterioration of filtration accuracy.

In this embodiment, the blade surface D of the rotary blade (5) is
Was made a logarithmic spiral curve in the radial direction and was vertical to the vertical direction. This is as long as each horizontal section of the blade surface D has the above-mentioned predetermined logarithmic spiral curve, if necessary. It may be inclined in the vertical direction. Also, two rotor blades (5) were provided symmetrically about the rotation axis in consideration of the rotation balun, but one or three or more rotor blades (5) were provided depending on the scale and application of the filter dryer to be applied. You may be taken.

〔The invention's effect〕

As described above, according to the filter / dryer of the present invention, the wet filter cake layer after filtration can be easily stirred,
The efficiency of contact with the aerated dry gas may be increased to facilitate its drying. The filtered and dried powder can be discharged smoothly and with a small residual amount. The stirring function and the discharging function can be achieved by one type of rotary blade. The accuracy of closing the powder discharge port can be easily ensured. Outstanding effects such as etc. can be achieved.

[Brief description of the drawings]

1 is a front sectional view showing a filter-drying apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is a sectional view taken along the line AA of FIG. (1) …… Main body, (2) …… Lower lid, (3) …… Slurry supply port, (4) …… Rotary shaft, (5) …… Rotary blade, (6) …… Porous filter plate, (7) ... filter cloth, (8) ... filtrate outlet,
(9) ... Powder discharge port.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location B01D 29/04 530A 29/38 550D (56) Reference JP-A-61-21708 (JP, A) JP-A-62-1416 (JP, A) JP-A-1-184008 (JP, A) JP-A-51-76070 (JP, U) JP-B-57-52847 (JP-B2) JP-B-60-4574 (JP, Y2)

Claims (1)

(57) [Claims] 1. A body formed in a bell-shaped housing and having a slurry supply port on the upper part, and a filter material and a filter plate which are layered and supported at the lower opening of the main body, and a filtrate discharge port and a powder discharge port are provided. A filtration / drying apparatus comprising: a lower lid having; a rotary shaft vertically rotatably provided in an inner center of a main body; and a stirring / scraping rotary blade attached to a lower end of the rotary shaft, The powder outlet is provided with its inner opening located at the outer peripheral portion of the filter plate near the inner wall of the main body, and one blade surface with respect to the rotation direction of the rotary blade is an inclined flat surface whose front end is the front edge. A filtration drying apparatus, wherein the other blade surface is formed by a curved surface that draws a logarithmic spiral curve on a polar coordinate whose fixed point is the center of the rotation axis in its horizontal section, or an approximate curved surface thereof.