JPH1147571A - Apparatus for dissolving and suspending powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for dissolving and suspending powder wherein a dissolved suspension is prepared in a batch type, and the dissolved suspension is continuously drawn, and countermeasures are conducted enough for behavior inherent in powder. SOLUTION: The apparatus for dissolving and suspending powder is provided with a closed vertical cylindrical tank 12 as a dissolving and suspending tank. The tank 12 is divided into a left and right, a large and small, cross sectional area of two divisions communicating with each other at lower parts by a barrier plate 12d extending from a lower edge located a specified distance away from and above the bottom plate to the top part of the tank. Powder is allowed to be dissolved and/or to be suspended into liquid in a first division 14 with the large cross sectional area. The first division 14 is provided with an agitator 18 having an agitating blade 18a at a position lower than the lower edge of the barrier plate 12d. A powder-introducing port 20, an air-communication pipe 22 provided with a filter 22a, and a liquid-injecting pipe 24 are provided on the top part of the tank. An injection nozzle 24a is provided on the edge of the liquid-injecting pipe 24. A second division 16 with the small cross sectional area is provided with an electrode liquid level detector 28 and a penetrating hole 30 communicating with the open air and penetrating the side wall of the tank at a position higher than a higher liquid level (HWL).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for dissolving and suspending a powder, and more particularly, to a method of dissolving and suspending a powder in a liquid batchwise and continuously dissolving a powder of a predetermined concentration. And a device for dissolving and suspending powder.

[0002]

2. Description of the Related Art In the chemical industry, particularly in the field of water treatment, a suspension in which powder is suspended in a liquid or a solution in which powder is dissolved in a liquid are often prepared. For example, limestone powder is suspended in water to prepare a limestone slurry, activated carbon powder is suspended in water to prepare an activated carbon slurry, or slaked lime powder is dissolved in water to prepare a slaked lime aqueous solution. . By the way, powder is inherently
Poor liquid wettability, making it difficult to dissolve or suspend in liquid. In addition, the powder is poor in fluidity, and exhibits characteristics specific to the powder, such as floating in the air, scattering, adhesion to a wall surface, aggregation in a liquid, sedimentation, and the like.

[0003] The operation of dissolving and suspending powders can be performed in various ways depending on the physicochemical properties of the powder, the manner in which the powder is supplied, the properties of the liquid in which the powder is dissolved and suspended, and the manner in which the liquid is supplied. Although it is performed, the conventional powder dissolution and suspension apparatus has a relatively simple configuration in consideration of the difficulty of handling the powder, and basically includes a tank equipped with a stirrer, When preparing a solution of body slurry or powder, it is a batch-type apparatus that first puts a liquid in a tank, then puts the powder into the liquid and stirs to prepare a dissolved suspension. Then, the prepared dissolved suspension is withdrawn from the tank, and when the tank is almost empty, the dissolved suspension is prepared again.

[0004]

However, the conventional powder dissolution / suspension apparatus has the following problems. First, if the preparation of the dissolution suspension was a batch system, the dissolution suspension was also extracted in a batch system, and very few dissolution suspensions could be continuously extracted. That is, in a conventional powder dissolution suspension apparatus, a predetermined amount of liquid is put into a suspension dissolution tank, a predetermined amount of powder is suspended and dissolved in the liquid, and a suspension of powder having a predetermined concentration is dissolved. Is prepared. The dissolution suspension is then withdrawn. Then, when the dissolved suspension is almost exhausted, the extraction is stopped, and the dissolved suspension is prepared. For this reason, it was practically impossible to continuously extract the dissolved suspension. Second, there are insufficient measures against the behavior peculiar to powder. That is, in order to dissolve and suspend the powder in the liquid, a certain amount of strong stirring is necessary. However, if the liquid in the tank is strongly stirred, the liquid level detector may malfunction due to the stirring flow of the stirrer. In particular, when using an electrode type liquid level detector, the electrodes fluctuate due to the agitated flow, causing many malfunctions, and furthermore, the electrodes may come into contact with each other and be damaged. . In addition, the powder scattered from the tank to the outside sometimes caused a hygiene problem.

[0005] An object of the present invention is to prepare a dissolved suspension in a batch system, and to continuously withdraw a dissolved suspension having a predetermined concentration over a period of withdrawing the dissolved suspension. It is an object of the present invention to provide an apparatus for dissolving and suspending powder, which takes sufficient measures against the problem.

[0006]

Means for Solving the Problems To achieve the above object, a powder dissolution and suspension apparatus according to the present invention is an apparatus for dissolving and / or suspending a powder in a liquid, which is a closed type. Formed as a vertical cylindrical tank, partitioned by a partition extending from the lower edge located a predetermined distance above the bottom plate to the tank top, while communicating with the lower part, two large and small left and right cross-sectional areas,
A first section having a large cross-sectional area for dissolving and / or suspending the powder in the liquid contained in the tank; and a first section having a stirring blade at a position below the lower end of the partition wall. A stirrer is provided at the top of the tank in the first section, and a powder inlet for introducing powder, a liquid inlet for injecting liquid, and an air communication pipe with a filter are provided, respectively. In the second section having a small cross-sectional area, a liquid level detector for detecting the liquid level in the tank is provided, and a through-hole communicating with the outside air is provided.
It is characterized in that it is provided through the tank side wall at a position higher than the high liquid level set by the liquid level detector.

In the present invention, the term "dissolve and / or suspend" means to dissolve powder, suspend powder, partially dissolve powder, and suspend the rest of powder. And hereinafter simply referred to as “dissolve and suspend”. In this specification, a liquid in which powder is dissolved and suspended is referred to as a dissolved suspension.
The shape of the partition is not particularly limited as long as it is not of a complicated shape to which the powder easily adheres. Preferably, the partition is a flat plate, but it is not necessary to be a flat plate. For example, the partition may be a cylindrical plate curved outward or inward from the center line of the tank, or an elliptic cylindrical plate. The distance between the lower edge of the partition and the bottom plate is in the range of 10 to 70% of the height of the lower liquid level (LWL). For example, when the partition is a flat plate, the partition is arranged so as to divide the diameter into 2: 1 to 5: 1. The type of the stirrer is not limited as long as the powder and the liquid can be efficiently mixed so that the powder concentration in the tank becomes uniform, but is preferably a turbine blade. The position of the stirrer may be in the first area, but from the viewpoint of stirring efficiency, the stirrer is positioned such that the axis of the stirrer is located near the center axis of the tank. The position of the stirring blade of the stirrer is such that the distance between the top and bottom surfaces of the stirring blade is 1/5 to 1/2 of the distance between the lower edge of the partition and the bottom plate. The liquid level detector is not limited in type as long as it can detect the liquid level, but in practice,
An electrode type liquid level detector used for detecting the liquid level of the dissolved suspension is preferred.

In the present invention, one of the functions of the liquid to be injected is to capture the powder floating in the tank and wash away the powder attached to the tank wall and the like by the liquid injected from the injection port. I have one. Therefore, the type of the injection port is not only capable of injecting the liquid into the tank, the injected liquid can capture the powder floating in the tank, and wash away the powder attached to the tank wall and the like. Make it possible. In addition, as long as the pouring port can capture the powder floating in the tank by the injection liquid and wash away the powder attached to the tank wall, etc., even in the ceiling of the closed vertical cylindrical tank, The upper tank wall located above the high liquid level may be used. Therefore, preferably, the injection port has an ejection nozzle for ejecting the liquid downward in a conical shape with a wide apex at a lower end, and the ejection nozzle is located above a high liquid level set by the liquid level detector. So that it is located at In addition, the powder inlet, when the liquid injected from the inlet is wet over the inlet, the powder adheres to the inlet, gradually thickens, and eventually becomes clogged. In order to prevent this, the powder inlet may be covered with a cover. That is, preferably, the powder introduction port includes a shielding plate that shields the powder introduction port from the liquid injected into the tank from the injection port. As long as the powder introduction port can be shielded from the liquid injected from the injection port, the shape of the shielding plate is arbitrary, and may be a simple plate-shaped shielding plate or a cylindrical shielding plate surrounding the introduction port.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Embodiment This embodiment is one of embodiments of the powder dissolving and suspending apparatus according to the present invention, in which the present invention is applied to an apparatus for dissolving and suspending slaked lime powder in a liquid. FIG. 1 is a schematic longitudinal sectional view showing the configuration of a powder dissolving and suspending apparatus, and FIG. 2 is an arrangement view showing the arrangement of partitions and a stirrer shaft when the powder dissolving and suspending apparatus of FIG. 1 is viewed from above. It is. Powder dissolving and suspending apparatus 10 of the present embodiment
The device (hereinafter abbreviated as device 10) includes a closed vertical cylindrical tank 12 as a tank for dissolving and suspending powder in a liquid. As shown in FIG. 1, the tank 12 includes a tank body 12a, a flat plate-like upper lid 12b that can be attached to and detached from an upper flange of the tank body 12a, and a lower edge positioned a predetermined distance above the bottom plate 12c of the tank body 12a. And a flat partition wall 12d extending from the upper lid 12b to the outer lid 12b while extending the cylindrical center line of the tank main body 12a. The tank 12 has two large and small cross-sectional areas communicating with each other at a communication portion 12e at the lower part of the tank by a partition wall 12d, that is, a first section 14 having a large cross-sectional area and a second section 16 having a small cross-sectional area. In addition, as shown in FIG. In this embodiment, the partition 12d is provided at a position where the diameter is divided into two to one.

At the center of the tank main body 12a in the first section 14, a stirrer 18 is provided so as to penetrate the upper lid 12b.
As the stirring blade 18a is each other are provided as close as possible to the bottom plate 12c of the tank body 12a, and the distance D ₁ of the the upper edge of the stirring blade 18a to the bottom plate 12c, distance from the lower edge of the partition wall 12d to the bottom plate 12c in the range of 1 / 5-1 / 3 of D _2.

In the first section 14 of the upper lid 12b, a powder introduction nozzle 20 for introducing the powder conveyed by the air conveying system together with the conveying air, and an external air for discharging the conveying air carrying the powder to the outside air. Supply pipe 2 for supplying a liquid such as water for dissolving and suspending a powder.
4 are provided. At the tip of the powder nozzle 20,
In order to prevent liquid ejected from a liquid ejecting nozzle 24a to be described later from catching on the opening of the powder introducing nozzle 20, a conical cover 20a is provided as a shielding plate for the liquid. A filter 22a for capturing the powder so that the powder does not escape to the outside air is attached to the upper end of the communication pipe 22. In addition, when the powder is introduced, the smaller the amount of the entrained air, the smaller the amount of the entrained air as much as the introduced powder is separated from the air without flowing in the tank 12 and gently settles on the liquid surface. Is preferred. If the entrained air is reduced, the load on the filter 22a is reduced, and
2a can have a simple structure. As a powder transfer system with a small amount of entrained air, a system using a Monopump (trade name) for transferring fine powder manufactured by Hyoshin Equipment Co., Ltd. is preferable. A known measuring device (not shown) capable of measuring the amount of introduced powder is provided outside the tank 12. The liquid supply nozzle 24 is provided at the tip thereof with an injection nozzle 24a for injecting a liquid in a spray form, and the injection nozzle 24a is located above a higher liquid level set by an electrode type liquid level detector 28 described later. Thus, it is arranged on the upper lid 12b. The spray nozzle 24a is a nozzle that radially sprays the liquid in all directions, and is configured to wash the air layer on the liquid surface in the tank 12, the upper lid 12b, the side wall of the tank body 12a, the partition wall 12d, and the surface of the stirring shaft 18. , A nozzle for ejecting liquid. The spray nozzle 24a is preferably located at the center of the first section 14 of the upper lid 12b in order to wash away the powder adhering to various places in the tank 12. A drain nozzle 26 is provided on the lower tank wall of the tank body 12a in the first section 14. In the above-described example, the liquid supply nozzle 24 is
4, the liquid supply nozzle is connected to the tank main body 24a, for example.
May be provided on the side wall above the high liquid level (HWL) of
Further, the number of nozzles is not limited to one, and a plurality of nozzles may be provided.

On the other hand, in the second section 16, an electrode type liquid level detector 28 is mounted through the upper lid 12b. The electrode type liquid level detector 28 includes a plurality of electrode rods 28a extending to the liquid level to be detected, and detects that the electrode rod and the liquid level have come into contact with each other, and the liquid level is at a contact position with the electrode rod. Detect that. When the liquid level reaches the high liquid level (HWL) and the low liquid level (LWL), an electrode rod for outputting a signal to that effect is also provided. In the second section 16, a communication hole 30 communicating with the outside air is provided with a high liquid level (HWL).
It is provided at a higher position through the tank wall of the tank body 12a. Through the communication pipe 22 of the first section 14 and the communication hole 30 of the second section 16, the air layer on the liquid level of the first section 14 and the air layer on the liquid level of the second section 14 are substantially equal to the atmospheric pressure. Pressure. Further, the communication hole 30 also functions as an overflow hole that overflows the liquid to the outside when the liquid level rises above the HWL. Further, an extraction nozzle 32 for extracting the dissolved suspension is provided on the lower tank wall of the tank body 12a in the second section 16. The dissolved suspension is adjusted to have a uniform powder concentration in the first section 14, enters the second section 16 through the lower communication portion 12 e, and further has a uniform powder concentration, and is sent from the extraction nozzle 32. Liquid.

[0013] Powder introduction nozzle 20, liquid supply nozzle 2
4. The drain nozzle 26 and the dispensing nozzle 32 for the dissolved suspension are respectively connected to a powder transport pipe, a liquid supply pipe, a drain pipe, and a liquid feed pipe (not shown).

Next, a method for preparing a dissolved suspension using the apparatus 10 will be described with reference to FIG. First, the first preparation step of preparing a dissolved suspension with the tank 12 empty is performed.
While monitoring the liquid level in the tank, a first predetermined amount of liquid (for example, an amount such that the liquid level reaches the lower liquid level LWL) is supplied from the liquid supply nozzle 24 to the tank 12. Next, a predetermined amount of powder is introduced from the powder introduction nozzle 20. After the introduction of the powder is finished, the movement of the powder in the air on the liquid is calmed, and the time for the powder to fall on the liquid surface is measured, and after that time, the liquid is further supplied from the liquid supply nozzle 24. I do. When the liquid is supplied, the liquid is injected from the injection nozzle 24a so as to flush the air layer on the liquid surface in the tank 12, the upper lid 12b, the side wall of the tank body 12a, the partition 12d, and the surface of the stirring shaft 18.
As the liquid is introduced, the liquid level in the tank 12 rises.
Until the liquid level detector 28 detects the high liquid level (HWL),
The liquid is introduced, and when the liquid reaches the high liquid level, the introduction of the liquid is stopped. The liquid ejected from the ejection nozzle 24a joins the liquid in the tank 12 while catching the scattered powder. Next, the mixture is stirred by the stirrer 18 to prepare a powder suspension having a predetermined concentration. In addition, the stirrer 18
Except when the operation of the apparatus 10 is stopped, the apparatus is always operating and stirring the liquid in the tank. At the time of preparing the dissolved suspension, the carrier air is released to the atmosphere via the communication tube 22, and the powder accompanying the carrier air is captured by the filter 22 a at the tip of the communication tube 22. Does not scatter powder.

When the first step of preparing the dissolved suspension is completed, the process proceeds to the step of extracting the dissolved suspension. The dissolved suspension adjusted to a predetermined concentration is extracted via the extraction nozzle 32 and a liquid sending pipe (not shown). As the dissolved suspension is withdrawn, the liquid level in the tank 12 gradually decreases and reaches the lower limit of operation LWL. When the liquid level detector 28 detects that the liquid level has dropped to LWL, the process proceeds to the second step of preparing the dissolved suspension.

In the second step of preparing a dissolved suspension, a dissolved suspension is prepared while the extraction of the dissolved suspension is continued.
First, a predetermined amount of powder is supplied from the powder supply nozzle 20. After finishing the supply of the powder, as in the first preparation step, the movement of the powder in the air on the liquid calms down, and the time for the powder to drop to the liquid surface is measured. A liquid such as water is supplied from the supply nozzle 24. When supplying the liquid, the liquid is supplied from the injection nozzle 24a to the air layer on the liquid surface in the tank 12, the upper lid 12b, the side wall of the tank body 12a, the partition 1
2d, spraying is performed so that the surface of the stirring shaft 18 is washed away. As the liquid is introduced, the liquid level in the tank 12 rises. The liquid is introduced until the liquid level detector 28 detects the high liquid level (HWL), and the introduction of the liquid is stopped at the high liquid level. At the bottom of the tank including the communicating portion 12e, sedimentation of the powder is prevented by the strong swirling flow of the stirring blade 18a, and a dissolved suspension having a uniform concentration is obtained.
2 does not become blocked by the sedimentary sediment of the powder. Thereafter, while repeating the second adjustment step, the dissolved suspension is continuously extracted from the extraction nozzle 32.

In this embodiment, the partition 12d of the first section 14
The liquid in the vicinity is stirred with a high mixing effect causing a turbulent flow due to the baffle effect of the partition wall 12d, and the powder supplied from the powder introduction nozzle 20 is rapidly dissolved and suspended.

On the other hand, the liquid in the second area 16 is
Thus, the liquid is substantially partitioned from the liquid in the first area 14, and the volume is small, so that the liquid is in a gentle stirring state.
As a result, the liquid level in the second area forms a gentle surface without movement, and the movement of the liquid is slow, so that the electrode rod of the liquid level detector 28 is swung like a conventional powder dissolution and suspension apparatus. There is no malfunction caused by moving. Also, the partition 12d
As a result, the movement of the powder is interrupted, so that the powder is not scattered at all in the second area 16 and does not adhere to the electrode rod of the liquid level detector 28, the side wall of the tank body 12 a and the upper lid 12. Therefore, the powder does not scatter from the through holes 30 provided on the tank side wall of the second section 16.

[0019]

According to the structure of the present invention, in the first zone, a dissolved suspension having a uniform powder concentration in the tank is prepared in a batch manner by the stirring effect of the stirrer and the baffle plate effect of the partition walls. ,
A dissolved suspension having a predetermined powder concentration can be continuously extracted. In addition, poor wettability and fluidity, scattering, adhesion,
Equipped with sufficient countermeasures for powder-specific properties and behavior such as easy sedimentation, the powder does not scatter outside the device, the liquid level detector does not malfunction, and the tank wall, The amount of powder adhering to the tank bottom plate and the like is also small, and operations such as cleaning the inside of the tank can be reduced. Further, by shielding the powder inlet from the liquid injected from the injection port with the shielding plate, it is possible to prevent the liquid from the injection port from hanging on the introduction port. It is possible to prevent the powder from adhering to the inlet and blocking the powder inlet due to the adhesion.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing a configuration of a powder dissolution suspension apparatus.

FIG. 2 is an arrangement view showing the arrangement of the partition walls and the shaft of the stirrer when the apparatus for dissolving and suspending the powder of FIG.

[Explanation of symbols]

 10 Example of powder dissolution and suspension apparatus according to the present invention 12 Vertical cylindrical tank 12a Tank body 12b Top lid 12c Bottom plate 12d Partition wall 14 First section 16 Second section 18 Stirrer 18a Stirrer blade 20 Powder introduction nozzle 20a Cover 22 Communication pipe 22a Filter 24 Liquid supply nozzle 24a Injection nozzle 26 Drain nozzle 28 Electrode type liquid level detector 28a Electrode rod 30 Communication hole 32 Extraction nozzle

Continued on the front page (72) Inventor Hiroo Yoshida 5-5-16-1 Hongo, Bunkyo-ku, Tokyo Organo Corporation

Claims (3)

[Claims] An apparatus for dissolving and / or suspending a powder in a liquid, which is formed as a closed vertical cylindrical tank, and extends from a lower edge located a predetermined distance above a bottom plate to a tank top. The partition wall is divided into two large and small cross-sectional areas on the left and right while communicating with each other at the lower part, and a tank is provided for dissolving and / or suspending the powder in the liquid contained in the tank in the first section having a large cross-sectional area. A stirrer is provided in the first section so as to have a stirring blade below the lower end of the partition, and a powder inlet for introducing powder and a liquid are provided in the upper part of the tank in the first section. A liquid inlet for liquid supply, and an air communication pipe with a filter are provided respectively, and a liquid level detector for detecting the liquid level in the tank is provided in the other second section having a small cross-sectional area, and The through-hole communicating with the outside air is higher than the high liquid level set by the liquid level detector. A powder dissolution / suspension device, which is provided at a position that penetrates the tank side wall. 2. The liquid injection port has an ejection nozzle for ejecting liquid radially in all directions at a lower end thereof, and is arranged such that the ejection nozzle is located above a higher liquid level set by the liquid level detector. The apparatus for dissolving and suspending powder according to claim 1, wherein the apparatus is used. 3. The powder introduction port according to claim 1, wherein the powder introduction port includes a shielding plate that shields the powder introduction port from liquid injected into the tank from the liquid injection port. Dissolution suspension equipment for powder.