Bubble generating device

Abstract

To provide a bubble generating device which makes bubbles and oil contents finer, and can be adapted to various purposes.SOLUTION: A bubble generating device 1 is structured by stacking a plurality of cylindrical bodies 7 formed of a cylindrical frame 5 and a plurality of protrusions 6 protruding from the frame 5 to a center in a cylindrical axis direction. A radial groove 12 in a radial direction which has an U-shape and opens upward in a circumferential cross section (a cross section A-A in Fig.2) is formed on an upper surface (an opening to a downstream side in a direction R of an air flow and water flow) of the plurality of protrusions 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an air bubble generating device for use in sewage purification equipment that utilizes aerobic bacteria to purify water contaminated with mineral oil, vegetable oil, etc., or sludge water when it is discharged. [Background technology]

[0002] In a factory or the like that uses water, a method is generally used to purify water contaminated with mineral oil, vegetable oil, etc. by treating the contaminated water with aerobic bacteria, etc., and purifying the contaminated components by propagating the aerobic bacteria, etc. In such a wastewater purification device, in order to propagate the aerobic bacteria, etc., it is necessary to mix fine air bubbles into the wastewater to promote oxygen respiration and create a living environment for the aerobic bacteria, etc. Such a device for mixing and generating fine air bubbles in wastewater has been conventionally used in a structure that is placed in the wastewater to be purified, discharges air from an air outlet provided at the bottom end of a pipe such as a cylinder, and arranges an air bubble finer means with many protrusions in the upward water flow generated by this air flow to finely refine the air bubbles and promote purification of the wastewater (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4749961 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional bubble mixers, cavitation or the like is generated in the wastewater, and the bubbles are broken down by changes in water pressure, thereby purifying the wastewater, etc., more effectively. However, in recent years, it has been known that the decomposition of oil by bacteria, etc., is promoted by making the oil and bubbles, which are the main components of dirt, finer, and there has been a demand for bubble generators that can make bubbles and oil finer. In addition, the applications of bubble generators are not limited to wastewater purification, but are diversifying to include emulsification, gas-liquid reaction, deoxidation, and pulverization, and existing bubble mixers are insufficient in making bubbles and oil finer, so there has been a demand for bubble generators that can fully meet these applications.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide an air bubble generating device having a structure capable of further finely breaking down air bubbles and oil by generating powerful Karman vortices within the device. [Means for solving the problem]

[0006] The air bubble generating device of the present invention, which solves such problems, is a bubble generating device for use in liquid and is positioned above an air outlet connected to an air supply source, and is configured as follows: a cylinder consisting of a cylindrical frame and a number of protrusions protruding from the frame toward the center, stacked in the axial direction, the protrusions of the cylinders being set to a predetermined length so that their tips face each other at the center to form an opening for generating cavitation, the multiple cylinders are positioned at an upper position where the air ejected from the air outlet rises, with the center of the opening and the center of the air outlet aligned in the axial direction of the cylinders, and at least one of the multiple protrusions has a radial groove formed on its upper surface which is U-shaped in circumferential cross section and opens upward.

[0007] It is desirable that at least one of the plurality of protrusions has a plurality of stepped collision surfaces on its underside that face and intersect at right angles with the airflow ejected from the air ejection port.

[0008] It is also preferable that at least one of the plurality of protrusions has the U-shaped groove and the plurality of collision surfaces on the same protrusion.

[0009] It is more preferable that the groove that is U-shaped in the circumferential cross section and opens upward has a structure in which a deeper groove is provided at the groove bottom. Effect of the Invention

[0010] According to the present invention, at least one of the protrusions of the cylinder has a structure in which a groove that is U-shaped in circumferential cross section and opens upward is formed on the upper surface. This causes Kármán vortices to be generated in the U-shaped portion, and the air bubbles and oil are further broken down into finer particles, thereby enabling the decomposition of the oil by bacteria, etc. to be carried out more efficiently. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a side cross-sectional view of an air bubble generating device according to a first embodiment of the present invention. [Diagram 2] A plan view of the cylindrical body of the device. [Diagram 3] Side view of the cylinder [Figure 4] Bottom view of the cylinder [Diagram 5] FIG. 3 is an enlarged cross-sectional view of the protrusion of the cylindrical body. [Figure 6] FIG. 2 is a perspective view of the cylindrical body as seen from below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an air bubble generator according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side cross-sectional view of an air bubble generator according to an embodiment of the present invention. The air bubble generator 1 is disposed above an air outlet 2 connected to a known air supply source (not shown) such as a blower. The air bubble generator 1 is fixed and supported by a fixture 4 in a septic tank 3 for storing liquid such as sewage, and is used in the liquid such as sewage. The air bubble generator 1 is constructed by stacking a plurality of cylinders 7 in the axial direction, each of which is made up of a cylindrical frame 5 (see FIG. 2) and a plurality of protrusions 6 (see FIG. 2) protruding from the frame 5 toward the center. The cylinders 7 are made of resin and fixed to each other by ultrasonic welding. The air bubble generator 1 is fixed and supported by bolts 10 using an annular support 9 inside a normal cylindrical outer cylinder 8.

[0013] Next, the cylindrical body 7 will be described with reference to Figs. 2 to 6. The cylindrical body 7 is composed of a cylindrical frame 5 and a plurality of protrusions 6 protruding from the frame 5 toward the center. The protrusions 6 of the cylindrical body 7 are set to a predetermined length so that they face each other in the center and form an opening 11 for generating cavitation. The tip 6a is formed in an acutely pointed shape, and the opening 11 is formed so as to be star-shaped in a cross section (radial cross section) perpendicular to the arrow R (see Fig. 1), so that it is designed to generate stronger cavitation. Depending on the application, hair or the like may get clogged, so the acutely pointed shape of the tip can be modified to a flat end face shape perpendicular to the length direction (radial direction of the cylinder). In this case, the opening 11 is changed from a star-shaped cross section (cross section perpendicular to the axial direction) to an opening 11 having a substantially circular cross section. In the multiple protrusions 6, radial grooves 12 that are U-shaped and open upward in a circumferential cross section (cross section AA in Figure 2) are formed on the upper surface (downstream side in the air flow / water flow direction R) (i.e., the grooves 12 are formed in the length direction of the protrusions 6).

[0014] Furthermore, groove 12, which is U-shaped in circumferential cross section and opens upward, has an additional deep groove 13 at the bottom of the groove. Groove 12 and deep groove 13 are formed to open toward the downstream side in the relative direction of the air current and water current (arrow R), and are shaped to form Karman vortices (shown by arrow K in FIG. 5). The formation of Karman vortices K applies shear force to the oil and gas bubbles in the wastewater, further breaking them down into finer particles (experiments have confirmed that the particle size becomes 3 to 7 microns).

[0015] As described above, the air bubble generator 1 is arranged with the center of the opening 11 aligned with the center of the air outlet 2 in the axial direction of the cylinders 7 in the direction of arrow R in which air rises above the air outlet 2, and is fixed and supported by the fixtures 4 in a septic tank 3 that stores liquid such as sewage. Adjacent cylinders 7 are arranged at a 22.5° offset in the rotational direction so that the protrusions 6 do not overlap when viewed in the axial direction of the cylinders 7 (direction of arrow R). Alignment protrusions 14 and positioning holes 15 are appropriately provided to arrange the cylinders 7 at a 22.5° offset from each other, and the cylinders 7 are positioned in the rotational direction and fixed in the axial direction. The cylinders can be fixed by ultrasonic welding or adhesive.

[0016] Furthermore, the multiple protrusions 6 have a pair of step-like collision surfaces 16 on the left and right sides in the length direction of the protrusions 6, which are perpendicular to the airflow (arrow R) ejected from the air ejection port 2 and are centered on the step end 17. The multiple step-like collision surfaces 16 are provided in a pair on the left and right sides on the bottom surface of the protrusions 6, centered on the step end 17, and each of the step-like collision surfaces 16 has three collision surfaces 18. In this embodiment, the groove 12 with a U-shaped cross section and the multiple collision surfaces 18 are provided on the top and bottom surfaces of the same protrusion 6, but a selective arrangement in which the groove 12 is provided only on the top surface of any of the multiple protrusions 6 or only the multiple step-like collision surfaces 16 are provided on the bottom surface can also be made by appropriate design, and can be changed according to the required ability to refine grease and air bubbles. [Industrial Applicability]

[0017] By utilizing the powerful Karman vortex, the present invention can be used not only for wastewater purification but also for a wide variety of other applications, such as emulsification, gas-liquid reactions, deoxidization, and pulverization. [Explanation of symbols]

[0018] 1. Air bubble generator 2 Air outlet 3. Septic tank 5 slots 6 Protrusion 7 Cylinder 8 Outer cylinder 11 Aperture 12 grooves 13 deep groove 16 Collision surface

Claims

1. A bubble generating device for use in liquid, the bubble generating device being disposed above an air outlet connected to an air supply source, The cylinder is configured by stacking a plurality of cylindrical bodies in the axial direction, the cylindrical bodies being each formed of a cylindrical frame and a plurality of protrusions protruding from the frame toward the center, the projections of the cylindrical body are set to a predetermined length so that their tips face each other at the center to form an opening for generating cavitation; the plurality of cylinders are disposed at an upper position where air ejected from the air ejection port rises, with the center of the opening and the center of the air ejection port being aligned in the axial direction of the cylinders; A bubble generating device, wherein at least one of the plurality of protrusions has radial grooves formed on its upper surface, the radial grooves being U-shaped in circumferential cross section and opening upward.

2. 2. The air bubble generation device according to claim 1, wherein at least one of said plurality of protrusions has a plurality of stepped collision surfaces on its underside, said collision surfaces being opposed to and perpendicular to the air flow ejected from said air ejection port.

3. The bubble generation device according to claim 1 , wherein at least one of the plurality of protrusions has the U-shaped groove and the plurality of collision surfaces on the same protrusion.

4. 4. The air bubble generating device according to claim 1, wherein the groove, which is U-shaped in circumferential cross section and opens upward, has an additional deep groove at its bottom.

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