JPH0679683B2 - Air diffuser - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is directed to a diffuser plate installed inside an aeration tank of a sewage treatment plant and used for aerating air and supplying oxygen to wastewater. It is about improvement.

(Prior art) A diffuser plate used in an aeration tank, etc. has uniform foamability and mechanical strength and durability that can be used in water for a long period of time. It also has bubbles of appropriate size suitable for aeration. It is required to be able to be uniformly discharged from each part of the diffuser plate, to be less likely to be clogged with a small pressure loss, and to be easily regenerated by backwashing even if it is clogged. As a conventional air diffusing plate, it is generally used that aggregates such as irregularly shaped cerben or silica sand, which are crushed and sized by porcelain, etc., are bonded by vitreous flux such as water glass and glaze. It was

However, since the air diffuser using such a conventional aggregate has an irregular shape of the aggregate, the pressure loss is large and the flux existing between the irregular aggregate particles is large when trying to secure a predetermined air flow amount. However, since the mechanical strength of the diffuser plate is inevitably reduced, there has been a problem that it cannot be thinned. In addition, since the voids that generate air bubbles by circulating air consist of irregularly shaped large voids formed between the irregularly shaped aggregate particles,
There is also a problem in that the size of the air bubbles to be diffused is not uniform, and the effect of regeneration by backwashing etc. when it is clogged due to long-term use is not always sufficient. Further, in the conventional air diffuser plate, the air flow rate is mainly adjusted by adjusting the particle size of the aggregate particles, so that there is a problem that the manufacturing process is complicated.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems of the related art, and it is possible to increase the bulk specific gravity and the strength while ensuring a predetermined air flow rate with less pressure loss, and moreover, uniform Air bubbles of various sizes can be generated uniformly from each part of the air diffuser, clogging is less likely to occur, pressure loss is also small, and regeneration processing such as backwashing when clogging is extremely easy, Completed to provide a diffuser plate that has good regeneration efficiency and that can be easily adjusted in the manufacturing process by changing the molding pressure, the amount of vitreous binder, etc. in addition to adjusting the particle size. Is.

(Means for Solving the Problems) The present invention made to solve the above problems is a spherical surface having a smooth surface obtained by combining spherical ceramic particles obtained by granulating a ceramic raw material powder with a vitreous binder. It is characterized by having a bending strength of 90 kg / cm ² or more and an air permeability of 1300 ml / cm ² · min · 120 mmAq or more.

As described above, the air diffuser of the present invention uses spherical ceramic particles obtained by granulating the ceramic raw material powder, instead of the conventional amorphous aggregate particles, so that the air flow rate is uniform and clogging occurs. It is difficult to use, and even if it becomes clogged even if it is used for a long period of time, the clogging can be easily regenerated with high pressure air, water or the like. Spherical ceramic particles have better packing properties than irregularly shaped aggregate particles, and the voids formed between spherical ceramic particles have a uniform size and distribution, and air bubbles of uniform size are diffused on the diffuser plate. Can be generated more uniformly from each part. It should be noted that the particle size of the spherical ceramic particles obtained by granulating the ceramic raw material powder is optimally about 0.5 to 3.0 mm. The aggregate may be mixed and used.

Such spherical ceramic particles are mixed with about 10 to 20% of a vitreous binder, and after being subjected to steps of press molding and firing, a diffuser plate is formed. The diffuser plate obtained consists of spherical ceramic particles whose surface is smoothly coated with a glassy binder.

As shown in the graphs of FIGS. 1 and 2, the air diffusing plate of the present invention is based on the shape difference of the aggregates, and has a higher bending strength and ventilation than the air diffusing plate using the conventional irregular shaped aggregate. There is a large difference in the relationship with the amount and the relationship between the wind pressure and the air flow rate. As shown in FIG. 1, the diffuser plate of the present invention has a bending strength of 90 kg / cm ² or more and an air flow rate of 1300 ml / cm ² · min · 120 mm.
It is a diffuser plate with Aq or more, which has extremely high mechanical strength and a large amount of ventilation. Further, since the air diffuser of the present invention has a small pressure loss as shown in FIG. 2, the air pressure may be half that of the conventional product in order to obtain the same ventilation amount. Further, even if the pressure increases, the rate of decrease in the air flow rate does not increase as much as the conventional product. Further, the air diffuser of the present invention can change the packing density of spherical ceramic particles by changing the pressure for press molding, and the air flow rate can be controlled quite freely.

Further, since the air diffuser plate of the present invention is the one in which the spherical ceramic particles obtained by granulating the ceramic powder are bonded by the vitreous binder, the surface of the aggregate is extremely smooth,
Therefore, the surface of the void formed inside is also smooth,
Compared with conventional amorphous particles, clogging is less likely to occur even after long-term use. Moreover, even if a clogging occurs, the clogging material can be easily removed as shown in Fig. 3 by backwashing with high pressure air, water, etc. because the surface of the aggregate and the void is smooth. There is an advantage that the clogging can be recovered and the diffuser plate can be easily regenerated.

Further, since the air diffuser of the present invention uses the granulated spherical aggregate, it is easy to control the particle size, and therefore the pore size becomes uniform, and as shown in FIG. It also has an advantage that the variation is extremely smaller than that using the conventional amorphous aggregate. The reason for limiting the numerical value of the air diffuser of the present invention is that the bending strength is less than 90 kg / cm ^2, which is almost the same as the conventional product and is significantly deteriorated by long-term use. 1300 ml / cm ²・ min ・ 120
If it is less than mmAq, it is not superior to a conventional product using an irregularly shaped aggregate, and a large capacity blower must be used. The present invention is an excellent diffuser plate having these synergistic effects.

Next, examples of the present invention will be described.

(Examples) Spherical ceramic particles having three kinds of particle size distributions shown as No. 1 to No. 3 in Table 1 were mixed with respective amounts of flux shown in the table, and molded into 10 Kg / cm ² . 30 cm by pressure
The air diffuser plates No. 1 to No. 3 of the present invention were obtained by press molding into a size of cm × 3 cm and firing at 1280 ° C. for 2 hours.

In addition, for comparison, an amorphous aggregate made of conventional cerben showing the same particle size distribution as No. 1 to No. 3 was used, and the same amount of flux was used in the same manner as the conventional product No. 1 to No. 3. Three types of comparative diffuser plates were obtained. Bending strength of the obtained 6 kinds of diffuser plates,
The air flow rate, product bulk specific gravity, porosity, etc. were measured. First result
Described in the table.

As is clear from the results of Table 1, the one using the spherical aggregate obtained by granulating the ceramic powder of the present invention has a higher bending strength and ventilation than the one using the conventional irregular-shaped aggregate. It was confirmed that both amounts were excellent. It was also confirmed that an air diffuser having a large bulk specific gravity can be obtained because it has excellent filling properties.

(Effects of the Invention) As described above, the present invention replaces aggregate particles such as irregular shaped sembel or silica sand obtained by crushing and sizing conventional ceramics, and has excellent filling properties and a smooth surface. Bending strength 90 Kg / cm ² or more with air-flow rate 1300 ml / cm ² min 120
Since it has a characteristic of mmAq or more, it is possible to increase the bulk specific gravity and strength while ensuring a predetermined ventilation volume, to generate bubbles of uniform size, and to prevent clogging and pressure. Loss is small, and even if it becomes clogged, it can be easily regenerated by backwashing, and the aeration rate can be changed by adjusting the molding pressure.
It has many advantages such as easy adjustment of the air flow rate in the manufacturing process.

Therefore, the present invention, as a diffuser plate that solves the conventional problems,
The areas that contribute to the development of industry are extremely large.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the bending strength of the product and the air flow rate, FIG. 2 is a graph showing the relationship between the air pressure and the air flow rate of the product, and FIG. 3 is the relationship between the product use time and the clogging recovery rate. FIG. 4 is a graph showing the relationship, and FIG. 4 is a graph showing the relationship between the average particle diameter of the aggregate of the product and the average pore diameter.

Claims (1)

[Claims] 1. A spherical ceramic particle obtained by granulating a ceramic raw material powder, which is bonded by a vitreous binder, and has a smooth surface. The bending strength is 90 kg.
/ cm ² or more and diffuser plate characterized by having an aeration rate 1300ml / cm ² · min · 120mmAq or more properties.