JPH0141470Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an air bubbling type slurry stirring device. More specifically, the present invention relates to an air bubbling slurry stirring device suitable for stirring a slurry in which deposits and crystallized substances tend to settle on the stirring air outlet during stirring.

[Conventional technology]

As a slurry stirring device, a method of mechanically stirring the slurry in a storage tank using a rotating stirring arm, an impeller, or the like is widely used. However, when stirring a slurry in which deposits or crystal precipitates are easily deposited during stirring, the rotating stirring arm or impeller gradually becomes swollen due to the deposits or crystal precipitates, making stirring difficult. Troublesome maintenance and repair work is required to remove particles and crystal deposits.
In addition, the materials that make up the rotating stirring arm, impeller, etc. need to have wear resistance so that they will not be worn away by the solids in the slurry, and in addition, if the slurry contains chemicals such as acids, In some cases, it is also necessary to have chemical resistance, and the material is limited. Air bubbling type slurry stirring equipment eliminates the above-mentioned difficulties, but if it continues to operate for a long period of time, deposits and crystal precipitates may stick to the nozzle, which is the air outlet, and the air for stirring may be ejected. It becomes increasingly difficult.

In addition, in order to prevent salt from precipitating at the air bubbling nozzle port provided in the salt-containing aqueous solution and clogging the nozzle port, it is necessary to continuously add water vapor to the air sent to the nozzle. It is known from the publication No.-47938. However, this known technique requires complicated water heating means and steam supply means, and may not be sufficiently effective depending on the type of deposit.

[Problem that the invention attempts to solve]

This invention uses an air bubbling method to ensure that even if the operation continues for a long time, the nozzle, which is the air outlet, will not be blocked by deposits or crystal precipitates, and the slurry, which is prone to deposits or crystal precipitates, will be removed. The purpose is to stir.

[Means for solving problems]

The device of the present invention will be explained using the example shown in FIG.

The present invention consists of a nozzle 1 which is an air outlet for stirring the slurry, a header 2 which is a pipe for supplying air or water to the nozzle 1, a water supply pipe 4, and an air outlet provided at the bottom of a slurry storage tank 10. This slurry agitation device includes a supply pipe 5 and a switching valve 6 for connecting the header 2 to either the water supply pipe 4 or the air supply pipe 5. In the device of the present invention, the switching valve 6 is
The timer causes the flow to flow through header 2 and into nozzle 1.
The fluid ejected from the header 2 is set to be switched from air to water and then back to air on a predetermined schedule, or the air pressure is set to a predetermined setting by the detection end 8 that detects the air pressure inside the header 2. It is preferable that the fluid flowing through the header 2 and spouted from the nozzle 1 be switched to water for a predetermined set time when the pressure exceeds the pressure.

[Effect]

The operation of the present invention will be explained with reference to FIG. FIG. 1A is a conceptual diagram of the apparatus while stirring the slurry. Air passes through the switching valve 6 and the header 2 from the air supply pipe 5, and is ejected into the slurry 7 from the nozzle 1 disposed at the bottom of the slurry storage tank 10. The slurry 7 is homogeneously stirred by air bubbles created by the ejected air. However, if a slurry in which deposits and crystal precipitates are easily deposited is stirred in this state for a long time, deposits and crystal precipitates will adhere to the nozzle 1.
As this deposit increases and solidifies, it gradually spreads to nozzle 1.
This may cause the air outlet to be restricted or even blocked.
FIG. 1B is a conceptual diagram illustrating the state of the switching valve 6 when removing deposits from the nozzle 1 by jetting water while continuing stirring. As shown in FIG. 1B, when removing deposits, the header 2 is connected to the water supply pipe 4, and water flows from the water supply pipe 4 through the switching valve 6 and the header 2 from the nozzle 1 into the slurry. At this time, the deposits on the nozzle 1 are removed by collision with the water stream or dissolution in the water stream. After removing the deposits, the switching valve 6 switches to the first
The state shown in FIG. A is returned, and air is again supplied to the nozzle 1 from the air supply pipe to perform air bubbling. In FIG. 1, a three-way rotary switching valve is illustrated as an example of the switching valve, but other commonly used switching devices can be used.

The switching valve 6 may be operated by the operator as needed by reading the pointer at the detection end 8 to detect changes in the back pressure within the header, but the detection end 8 is not essential. A schedule is determined in advance based on the time for the deposits on the nozzle 1 to increase during air bubbling and the time for the deposits to be removed by water jetting, and air bubbling and water jetting are performed as shown in Figure 2A. By setting the switching of the switching valve 6 to be performed alternately using a timer, continuous operation can be automatically performed without detecting the air pressure in the header 2 and without clogging the nozzle 1. When the detection end 8 is used, the detection end 8 detects an increase in the air pressure inside the header 2 due to an increase in the amount of deposits on the nozzle 1 during air bubbling.
By setting the switching valve 6 to inject water for a predetermined set time when the air pressure inside the header reaches a predetermined set pressure or higher, the nozzle 1 can be prevented from being blocked. Can operate automatically and continuously.

The device of the present invention is particularly effective when the slurry to be stirred contains sludge generated in the pickling solution when a steel material such as stainless steel is pickled with an aqueous nitric-fluoric acid solution. When iron fluoride crystallizes in the pickling tank and sludge is generated, when stirring the sludge when discharging it outside the tank, or when discharging waste liquid slurry containing a large amount of sludge discharged outside the tank. When stirring during processing, etc., iron fluoride that is firmly deposited on the air outlet of the air bubbling nozzle is dissolved by switching the air supply to water supply and jetting water from the air outlet, preventing the nozzle from clogging. This prevents troubles caused by

〔Example〕

Figure 3 shows the device of the present invention, with a stainless steel strip 11
This is an example of a sludge storage tank connected to one end of a pickling tank. 9 is a pickling tank for a nitric-fluoric acid aqueous solution, and 10 is a sludge storage tank connected to the pickling tank. Sludge mainly composed of iron fluoride that settled at the bottom of the pickling tank13
is collected in a sludge storage tank by a scraper 12. In the sludge storage tank 10, the nitric-fluoric acid aqueous solution becomes slurry 7 containing a large amount of sludge, and the header 2
After being stirred by air bubbling of air supplied from the nozzle 1, the liquid is sent to the next step, a solid-liquid separator (not shown). Sludge storage tank 1
Slurry 7 in Nozzle 0 tends to crystallize iron fluoride even during stirring, and also crystallizes at the air outlet of Nozzle 1.
However, since iron fluoride easily dissolves in water, a timer was used to set the switching valve to spray water for 10 seconds after air bubbling for 30 minutes, and the valve was activated automatically. , the nozzle was no longer blocked or blocked.

[Effects of the invention] The present invention is a slurry stirring device having the above-mentioned configuration, and the air bubbling type slurry stirring device of the present invention eliminates the need for the rotating stirring arm and impeller of the conventional mechanical stirring method. It eliminates the need for troublesome maintenance and repair work such as removing deposits on the top or replacing worn ones, and prevents the nozzle of conventional air bubbling systems from becoming constricted or blocked by deposits or crystallization. It becomes possible to stably stir a slurry in which precipitates and crystal precipitates are likely to be deposited during stirring without causing any trouble.

[Brief explanation of drawings]

Figure 1 is a conceptual diagram of the operation of the device related to the present invention, Figure 2 is a diagram showing the switching status of the switching valve drive device, and Figure 3 is a diagram showing the switching status of the switching valve drive device.
The figure shows an example of treatment of pickling sludge of stainless steel. DESCRIPTION OF SYMBOLS 1... Nozzle, 2... Header, 4... Water supply pipe, 5... Air supply pipe, 6... Switching valve, 7... Slurry, 8... Detection end, 9... Pickling tank, 10... …
Sludge storage tank, 11...Stainless steel strip, 12...
...Scraper, 13... Pickling sludge.

Claims (1)

[Claims for Utility Model Registration] (1) A nozzle 1, which is an air outlet for stirring slurry, disposed at the bottom of the slurry storage tank 10;
A slurry consisting of a header 2, which is a pipe that supplies air or water to a nozzle 1, a water supply pipe 4, an air supply pipe 5, and a switching valve 6 for connecting the header 2 to either the water supply pipe 4 or the air supply pipe 5. Stirring device. (2) A utility model registration request in which the switching valve 6 is set to switch the fluid flowing through the header 2 and spouted from the nozzle 1 from air to water and back from water to air on a predetermined schedule using a timer. The slurry stirring device according to item 1. (3) When the switching valve 6 detects the air pressure inside the header 2 at the detection end 8, when the air pressure reaches a predetermined set pressure or higher, the air flows through the header 2 and from the nozzle 1 for a predetermined set time. The slurry stirring device according to claim 1, which is configured to switch the ejected fluid to water.