JP3135218B2 - Powder supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder supply apparatus capable of supplying fine particles in minute amounts.
In particular, the present invention relates to a powder supply device that supplies a polymer flocculant for coagulating dissolved substances and the like in wastewater treatment.

[0002]

2. Description of the Related Art In wastewater treatment, as a method of removing suspended and dissolved substances in wastewater to obtain clear water having a predetermined reference water quality, and treating and disposing of the removed and separated sludge in a harmless form. In general, a coagulation method using a drug is widely used. A polymer flocculant is used as an agent for promoting the separation (solid-liquid separation) of this sludge and clear water.

[0003]

However, this polymer flocculant has a problem of poor solubility. That is, when this polymer flocculant is directly introduced into water, the respective particles adhere to each other before being dispersed and dissolved in water, resulting in so-called joint powder (mamako). Once the polymer flocculant has been turned into powder, it is difficult to dissolve it even if it is stirred for a long time,
The undissolved polymer flocculant does not contribute to the promotion of solid-liquid separation, resulting in wasted chemicals.

[0004] For this reason, conventionally, in order to prevent the generation of re-powdering, a screw feeder of a rotary extrusion system, an air using compressed air, and the like are used so that a small amount of the polymer flocculant is continuously supplied when it is put into water. Examples include a suction air dispersed supply method using an ejector, and a structure in which a polymer flocculant is dropped from a hopper onto a water film straightening plate and dissolved therein.

However, the polymer flocculant is not always supplied continuously, but is supplied intermittently according to an instruction from a timer or the like. For this reason, when the polymer flocculant is not operating, the moisture generated from the dissolution tank flows into the polymer flocculant supply pipe, causing blockage of the supply pipe, bridge phenomenon in the hopper, and dew condensation inside the ejector. There is a possibility that troubles such as adhesion of undissolved components on the current plate may occur.

In order to prevent this, in the conventional apparatus, it has been necessary to add secondary technology and functions such as supply of dry air or installation of a heater.

SUMMARY OF THE INVENTION The present invention provides a powder supply apparatus which can eliminate the flour with a simple configuration, and prevents the inflow of moisture and the like even when the supply is stopped to solve the problems such as the bridge of the powder. With the goal.

[0008]

[0009]

According to a first aspect of the present invention, there is provided a hopper for accumulating and storing powder, and a mixing chamber adjacent to the hopper, and a wall surface of the hopper on the mixing chamber side. At the same time, a slit is formed at the lower end of the hopper, and the bottom surface of the hopper is inclined to the slit side at an angle equal to or greater than the angle of repose of the powder , and further, an atmosphere is formed in which a low-pressure air flow is discharged into the mixing chamber toward the slit. Rutotomoni provided <br/> the use airflow discharge means, and wherein from the mixing chamber to the provision of the spray nozzle which opens towards the liquid bath to dissolve the powder.

[0010] According to a second aspect of the invention of this application, the spraying and moisture air flow discharge means for discharging a low pressure air stream into the nozzle toward the liquid bath, wherein the atmosphere forming air flow discharge means and the moisture characterized by providing a switching means for operating switching the airflow discharge means.

According to the present invention, an atmosphere in which the powder is scattered in the form of particles is formed in the mixing chamber. Since the air is agitated in a substantially closed room, a powder scattering atmosphere can be formed with a low-pressure air flow, and an atmosphere in which particles are uniformly distributed can be formed. Here, the air in the present invention is a concept including various stable gases such as nitrogen gas. By guiding the atmosphere containing the particulate powder to the liquid tank (dissolution tank), the powder can be supplied in units of particles, enabling efficient dissolution, and preventing the occurrence of repeated powder. it can. Also, if the low-pressure air flow is kept constant, the concentration of the powder scattered in the mixing chamber can be kept almost constant, so that the supply amount can be controlled by the supply time and accurate quantitative control can be performed. .

According to the first aspect of the present invention, a slit is provided at the lower end of the wall surface of the hopper for depositing and storing the powder, and the low-pressure air flow is blown from the slit to scrape the powder. here,
"Scraping" by the low-pressure air flow is performed by the following operation. When a low pressure air stream is blown into the hopper, the air stream flows between the powder particles, weakening the bond between the powders. And this air flow is recirculated into the mixing chamber due to collision with the powder. The lower end portion of the powder separated (disintegrated) for each particle in this manner is flowed to the reflux of the air flow and carried to the mixing chamber. The powder scraped out by such an action is scattered in the form of particles in the mixing chamber to form an atmosphere, and is guided to the liquid tank through the spray nozzle by this low-pressure air flow. Since the bottom surface of the hopper is inclined at an angle equal to or greater than the angle of repose of the powder, when the powder is scraped, the powder does not fall from above and form a bridge. Further, the bridge can be prevented by taking out the lower end portion while loosening the powder by the air flow as described above, instead of the natural fall. This makes it possible to supply a stable powder with a simple configuration.

According to the second aspect of the present invention, the spray nozzle is provided with an airflow discharging means for preventing moisture, and is operated so as to be switched with the airflow discharging means for forming an atmosphere for scraping powder from the slit. This switching operation can be performed with a simple configuration, for example, by forming an airflow with the same pump and switching the path by a valve. Due to this, even while the supply of the powder is suspended, the air flow is flowing through the spray nozzle, and the air pressure in the spray nozzle is slightly higher than the external pressure, so the moisture rises from the liquid tank Can be prevented, and adhesion and clogging of powder due to moisture can be prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A polymer coagulant supply device according to an embodiment of the present invention will be described with reference to the drawings. FIG.
1 is a treatment system diagram of a wastewater treatment facility to which a polymer flocculant supply device according to an embodiment of the present invention is applied. The wastewater is pumped from a raw water tank by a raw water pump, and the pH is adjusted in the reaction tank by adding an acid or an alkali. Due to this pH adjustment, metal components and the like dissolved in the raw water are precipitated as hydroxide of fine particles. However, since these are extremely fine particles, it takes a long time to perform precipitation separation, that is, solid-liquid separation as it is. Then, this waste water is transferred to a coagulation tank, and an aqueous polymer coagulant solution is added. By adding this polymer flocculant, the dissolved matter of the fine particles aggregates to become large particles and precipitates quickly. This liquid is transferred to a sedimentation separation tank, and solid-liquid separation is performed by gravity. The settled sludge is scraped to the center bottom of the settling tank by gentle rotation of the sludge scraping arm. The sludge is dewatered, shaped into a solid by a filter press, and disposed of. Then, the supernatant of the sedimentation separation tank is separated as water separated from the sludge suspension, subjected to a treatment such as a re-neutralization treatment, and then discharged as clear water.

In this treatment system diagram, a polymer flocculant aqueous solution to be added to the flocculation tank is prepared in a polymer flocculant dissolution tank, and is supplied to the flocculation tank in a fixed amount. The polymer flocculant dissolving tank is automatically supplied with water when the liquid level of the aqueous solution falls below a certain value, and supplies the polymer flocculant whose concentration has been reduced by the water supply from the polymer flocculant supply device. The polymer flocculant supply device according to the embodiment of the present invention is installed on the upper part of the polymer flocculant dissolving tank,
A small amount of the polymer coagulant is intermittently supplied to the polymer coagulant dissolution tank in accordance with an instruction from the control unit that performs the liquid level detection and the water supply control.

FIG. 2 is a structural view of a polymer flocculant supply apparatus according to an embodiment of the present invention, FIG. 2 is a plan view of the vicinity of a hopper 1 and a mixing chamber 3, and FIG. 5 is an enlarged view of a portion B in FIG. The hopper 1 in which the polymer flocculant 2 is stored is formed in a square column shape in which the bottom surface 1a is inclined at an inclination angle θ. This bottom surface 1a is adjacent to the mixing chamber 3
A slit 1b is formed at the lower end of the inclination, that is, at the lower end of the wall surface 1c that separates the mixing chamber 3 from the hopper 1, and the slit 1b forms the slit 1b.
And the hopper 1 are communicated. The inclination angle θ is set to 60 degrees, which is an angle exceeding the angle (angle of repose) at which the polymer flocculant 2 as a powder becomes a bridge. The lower end of the wall surface 1c is also cut out at the same angle of 60 degrees, and the interval between the slits 1b is 6 mm.

The mixing chamber 3 has a substantially cubic space, and a cylindrical powder spray nozzle 7 is connected to the opposite side of the hopper 1. The powder dispersing nozzle 7 is bent in an L shape, and the opposite side of the connecting portion of the mixing chamber 3 opens downward to the polymer flocculant dissolving tank.

The low pressure pump 5 has a pressure of 0.12 kg / c.
m ² G. This pump supplies a low-pressure air flow having a flow rate of about 72 to 74 (liter / minute) at a pressure of about 72 to 74. The low-pressure air flow is supplied to the atmosphere forming pipe 6 or the moisture-proof purge line 8 via the three-way solenoid valve 4. are doing. The atmosphere forming pipe 6 is fitted into the mixing chamber 3 from above, and is bent at a bottom surface of the mixing chamber 3 so as to be perpendicular to the hopper 1 (slit 1b). The distance between the tip of the atmosphere forming pipe 6 and the wall surface 1c is about 10 mm. The moisture-proof purge line 8 joins the bent portion of the powder spray nozzle 7 downward, that is, toward the melting tank.

The low-pressure pump 5 is constantly operating, and the three-way solenoid valve 4 is controlled to be switched by a control unit (not shown). In a standby state where it is not necessary to supply the polymer flocculant to the dissolving tank, the three-way solenoid valve 4 is switched to the moisture-proof purge line 8 side, and the flow of low-pressure air through the powder spray nozzle 7 prevents the inflow of moisture. are doing. When the water level in the dissolving tank drops and water is supplied and the polymer coagulant is replenished, the three-way solenoid valve 4 is switched to the atmosphere forming pipe 6 side, and low-pressure air is discharged from the tip of the atmosphere forming pipe 6. The polymer flocculant 2 in the hopper 1 from the slit 1b
A scattering atmosphere of the polymer flocculant is formed in the mixing chamber 3.

The operation of the polymer flocculant supply device having the above configuration will be described in detail. When the three-way solenoid valve 4 is switched to the atmosphere forming pipe 6 side in accordance with the instruction to supply the polymer flocculant, the low-pressure air flow formed by the low-pressure pump 5 is discharged from the atmosphere forming pipe 6. A part of the air flow passes through the slit 1b, flows into the hopper 1, collides with the polymer flocculant 2 accumulated in the hopper 1, and scrapes the lower end thereof. The scraped polymer flocculant 2 is blown into the mixing chamber 3. At this time, since the bottom surface 1a of the hopper 1 is inclined at an angle θ equal to or larger than the angle of repose, an amount corresponding to the blown-out polymer flocculant is always filled by the own weight of the polymer flocculant in the hopper, and air A blow-by is prevented. On the other hand, other air flows that did not flow into the hopper 1
And the mixture is refluxed to stir the inside of the mixing chamber 3. The blown-out polymer flocculant is mixed with the refluxed air to form a powder scattering atmosphere containing a certain amount of the polymer flocculant in the mixing chamber 3. The powder scattering atmosphere flows toward the powder spraying nozzle 7 by the low-pressure air flow and is supplied to the melting tank.

The inventor combined a mixing chamber air supply timer and a liquid level controller as a control device and supplied a polymer flocculant from the powder spraying nozzle 7 to perform a melting operation. Due to the scattered atmosphere, generation of sprinkled powder (mamako) did not occur at all.

On the other hand, when the three-way solenoid valve 4 is switched to the moisture-proof purge line 8 by an instruction to stop the supply of the polymer flocculant, the low-pressure air flow flows into the powder spray nozzle 7 through the moisture-proof purge line 8. Spills out of its tip. Thereby, the tip of the powder spraying nozzle 7 is always filled with the same air as when the polymer coagulant is supplied, so that the inflow of moisture from the melting tank can be prevented.

Here, according to the experiment, it was confirmed that the formation of the powder scattering atmosphere was generated at an air flow of a certain value or more, and there was always a correlation between the air flow and the supply amount of the polymer flocculant. . By the establishment of this correlation, it was confirmed that the mixing chamber 3 had reached a state of complete mixing.

Further, the hopper 1 is supplied by supplying a polymer flocculant.
Although the level of the polymer flocculant 2 deposited inside gradually decreases, as a result of experiments conducted by the inventors at various levels,
The H level around the deposition height of 330 mm and the L level around the deposition height of 220 mm vary only by about 20%, and ± 1 when the deposition level is around 270 mm as the standard level.
It has been found that it is possible to suppress the fluctuation range within the range of 0%, and it is possible to supply a substantially constant amount of the polymer flocculant by appropriately replenishing the polymer flocculant.

Therefore, it was found that the supply amount was hardly affected by the deposition height of the polymer flocculant 2 in the hopper 1 and could be adjusted by the supply time and the air volume. In addition, the supplied polymer flocculant becomes completely particulate and falls into the liquid, so that it is completely dissolved without becoming a flour, and the supply amount and the aqueous solution concentration are completely proportional, so that control is achieved. Become easy and accurate.

In this embodiment, a supply apparatus of a polymer flocculant for wastewater treatment has been described, but any apparatus may be used as long as it supplies minute fine powders similar to the polymer flocculant. It can also be applied to

The dimensions and angles shown in the above embodiment are merely examples, and the present invention is not limited to these dimensions and angles. The gas flow supplied from the low-pressure pump 5 is not limited to air, but may be another gas such as nitrogen.

[0028]

According to the present invention, since the powder scattering atmosphere is formed in the mixing chamber, it is not necessary to use a strong air flow, and the structure is simplified, and the powder is scattered in the form of particles. It can be supplied to a solvent that dissolves in a mixed state. Further, since it is easy to keep the powder concentration in the powder scattering atmosphere constant, there is an advantage that accurate quantitative supply control can be performed.

According to the first aspect of the present invention, the powder is sequentially supplied from the hopper, and the bridge does not occur because the powder is larger than the angle of repose of the powder. In addition, instead of dropping naturally, the lower end is scraped out while loosening the powder with airflow,
Bridges can be better prevented. In addition, since the air flow for scraping and the air flow for forming the atmosphere can be used in common, it is possible to supply uniform particulate powder with a simple configuration.

According to the second aspect of the present invention, even when the powder is not supplied, the low-pressure air flow flows out of the spray nozzle, so that steam or moisture from the melting tank flows into the supply device. without, it is never caused clogging and adhesion of the device.

[Brief description of the drawings]

FIG. 1 is a system diagram of a wastewater treatment facility to which the present invention is applied.

FIG. 2 is a configuration diagram of a polymer flocculant supply device according to an embodiment of the present invention.

FIG. 3 is a configuration diagram near a mixing chamber of the polymer flocculant supply device.

FIG. 4 is a sectional view taken along line AA in FIG. 3;

FIG. 5 is an enlarged view of the vicinity of a slit of the polymer flocculant supply device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hopper, 2 ... Polymer flocculant, 3 ... Mixing chamber, 4 ... Three-way solenoid valve, 5 ... Low pressure pump, 6 ... Atmosphere forming pipe, 7
... powder spray nozzle, 8 ... moisture-proof purge line

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-78632 (JP, A) JP-A-62-286532 (JP, A) JP-A-62-21632 (JP, A) JP-A-57-1986 195402 (JP, A) JP-A-9-327602 (JP, A) JP-A 54-74742 (JP, U) JP-A 52-15538 (JP, U) (58) Fields investigated (Int. ⁷ , DB name) C02F 1/52-1/56 B01D 21/01 B01J 4/00

Claims (2)

(57) [Claims] 1. A hopper for accumulating and storing powder, and a mixing chamber adjacent to the hopper, wherein a slit is formed at a lower end of a wall of the hopper on the mixing chamber side, and a bottom surface of the hopper is formed. On the slit side more than the angle of repose of the powder
Of is the angle tilted, further wherein the mixing chamber, Ru provided an airflow discharge means for atmosphere creation to discharge low pressure air flow toward the slit
And a spray nozzle that opens from the mixing chamber to a liquid tank that dissolves the powder. 2. A switching operation is performed between a moisture-proof air flow discharging means for discharging a low-pressure air flow into the spraying nozzle toward the liquid tank, and the atmosphere-forming air flow discharging means and the moisture-proof air flow discharging means. powder supplying device according to claim 1, characterized in that provided a switching means.