Impeller

Abstract

To provide an impeller which can reduce power required for rotation by improving supply efficiency of oxygen to water to be treated.SOLUTION: An impeller, which aerates and / or stirs water to be treated, comprises an aeration blade that aerates the water to be treated, and a stirring blade that stirs the water to be treated. The aeration blade and the stirring blade are respectively formed radially outward in a radial direction, and the stirring blade is inclined or curved toward rearward in a rotation direction of the impeller by the aeration blade.SELECTED DRAWING: Figure 3A

Description

Technical Field

[0001] The present invention relates to an impeller for a vertical-axis aeration and agitation device for biological water treatment equipment.

Background Art

[0002] As a biological treatment facility for biologically treating treated water such as sewage and wastewater, a method using an oxidation ditch tank in which an endless circulation water channel is formed is known. As an aeration and agitation device in this oxidation ditch tank, three types, namely, a vertical-axis type, a horizontal-axis type, and an inclined-axis type, are known. Patent Document 1 describes an impeller that is disposed in an oxidation ditch tank and rotates with the axial direction being a direction substantially perpendicular to the liquid surface of the drainage, that is, a direction intersecting the liquid surface, to perform aeration and agitation of the drainage.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to aerate and agitate the treated water in the oxidation ditch tank, it is necessary to keep the aeration and agitation device running for a long time. Therefore, it is desired that the impeller, which is always in contact with the treated water, improves the oxygen supply efficiency to the treated water without increasing the power of the aeration and agitation device.

[0005] Therefore, an object of the present invention is to provide an impeller that can reduce the power required for rotation by improving the oxygen supply efficiency to the treated water.

Means for Solving the Problems

[0006] As a result of diligent research into the above-mentioned problems, the inventors of the present invention have found that in an impeller comprising an aeration blade for aerating the water to be treated and a stirring blade for stirring the water to be treated, the stirring blade is inclined or curved toward the rear in the direction of rotation of the impeller relative to the aeration blade, thereby reducing the required power while maintaining the efficiency of oxygen supply to the water to be treated, and have completed the present invention. That is, the present invention is the following impeller.

[0007] The present invention, which solves the above problems, is an impeller that aerates and / or stirs water to be treated, comprising an aeration blade for aerating the water to be treated and a stirring blade for stirring the water to be treated, wherein the aeration blade and the stirring blade are each formed radially outward in the radial direction, and the stirring blade is inclined or curved toward the rear in the rotational direction of the impeller relative to the aeration blade.

[0008] According to the impeller of the present invention, the stirring blades are inclined or curved toward the rear in the direction of rotation of the impeller compared to the aeration blades, thereby reducing the resistance of the treated water to the operation of the stirring blades. This allows for aeration and stirring of the treated water with low power while maintaining a predetermined aeration performance by the aeration blades. As a result, it is possible to provide an impeller that can effectively increase oxygen supply efficiency with energy savings. In other words, by using this impeller, it is possible to provide a water treatment device that can effectively increase oxygen supply efficiency with energy savings.

[0009] Furthermore, in one embodiment of the impeller of the present invention, the stirring blade is characterized in that it is inclined toward the rear in the rotational direction of the impeller compared to the aeration blade by bending a planar plate at multiple points. This feature allows for the manufacturing of impeller blades with fewer steps compared to forming curved blades by continuously bending a flat plate. This significantly reduces the manufacturing cost and time of the impeller. In other words, it can drastically reduce the manufacturing cost and time of aeration and stirring equipment using this impeller.

[0010] Furthermore, in one embodiment of the impeller of the present invention, the upper end of the aeration blade is characterized by being bent or curved toward the direction of rotation. This feature allows the upper end of the aeration blade to bend or curve toward the direction of rotation, thereby efficiently accelerating the water to be treated on the impeller and improving aeration efficiency.

[0011] Furthermore, the stirring device using the impeller of the present invention provides a water treatment device that can effectively increase oxygen supply efficiency while saving energy.

[0012] Furthermore, the water treatment method using the stirring device of the present invention makes it possible to save energy and effectively increase oxygen supply efficiency. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an impeller that can reduce the power required for rotation by improving the efficiency of oxygen supply to the water to be treated. [Brief explanation of the drawing]

[0014] [Figure 1A] This is a schematic diagram illustrating the configuration of the biological treatment facility of the present invention when the endless waterway is viewed from above. [Figure 1B] This is a schematic diagram illustrating the configuration of the biological treatment facility of the present invention when the endless waterway is viewed from above. [Figure 2] This is a schematic diagram illustrating the structure of the vertical-axis type aeration and stirring device of the present invention in a cross-section of an endless waterway. [Figure 3A] This is a schematic perspective view showing an impeller in a first embodiment of the present invention. [Figure 3B] This is a schematic plan view showing an impeller in the first embodiment of the present invention. [Figure 3C] This is a schematic plan view showing an impeller in the first embodiment of the present invention. [Figure 3D]It is a schematic bottom view showing an impeller in the first embodiment of the present invention. [Figure 3E] It is a schematic bottom view showing an impeller in the first embodiment of the present invention. [Figure 3F] It is a schematic bottom view showing an impeller in the first embodiment of the present invention. [Figure 3G] It is a schematic cross-sectional view in the V-V direction of FIG. 3B showing an impeller in the first embodiment of the present invention. [Figure 3H] It is a schematic cross-sectional view in the V-V direction of FIG. 3B showing an impeller in the first embodiment of the present invention. [Figure 3I] It is a schematic cross-sectional view in the V-V direction of FIG. 3G showing an impeller in the first embodiment of the present invention. [Figure 3J] It is a schematic cross-sectional view in the V-V direction of FIG. 3G showing an impeller in the first embodiment of the present invention. [Figure 4A] It is a schematic perspective view showing an impeller in the second embodiment of the present invention. [Figure 4B] It is a schematic cross-sectional view in the V-V direction of FIG. 4A showing an impeller in the second embodiment of the present invention. [Figure 5A] It is a schematic perspective view showing an impeller in the third embodiment of the present invention. [Figure 5B] It is a schematic plan view showing an impeller in the third embodiment of the present invention. [Figure 6A] It is a plan view showing the appearance of an impeller in the fourth embodiment of the present invention. [Figure 6B] It is a bottom view showing the appearance of an impeller in the fourth embodiment of the present invention. [Figure 6C] It is a front view showing the appearance of an impeller in the fourth embodiment of the present invention. [Figure 6D] It is a rear view showing the appearance of an impeller in the fourth embodiment of the present invention. [Figure 6E] It is a left side view showing the appearance of an impeller in the fourth embodiment of the present invention. [Figure 6F] It is a right side view showing the appearance of an impeller in the fourth embodiment of the present invention. [Figure 6G] This is a perspective view showing the appearance of an impeller according to a fourth embodiment of the present invention. [Figure 7A] This is a plan view showing the external appearance of an impeller according to the fifth embodiment of the present invention. [Figure 7B] This is a bottom view showing the external appearance of an impeller according to the fifth embodiment of the present invention. [Figure 7C] This is a front view showing the external appearance of an impeller according to the fifth embodiment of the present invention. [Figure 7D] This is a rear view showing the external appearance of an impeller according to the fifth embodiment of the present invention. [Figure 7E] This is a left side view showing the external appearance of an impeller according to the fifth embodiment of the present invention. [Figure 7F] This is a right side view showing the external appearance of an impeller according to the fifth embodiment of the present invention. [Figure 7G] This is a perspective view showing the appearance of an impeller according to the fifth embodiment of the present invention. [Modes for carrying out the invention]

[0015] The impeller, agitator, and water treatment method of the present invention are primarily intended for use in vertical-axis aeration and agitation devices for biological water treatment facilities and in biological water treatment methods. Furthermore, the following explanations of the impeller and agitator also serve as explanations of the water treatment method.

[0016] [First Embodiment] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Figure 1A is a schematic diagram illustrating the configuration of the biological treatment facility 1 as viewed from above through the endless channel 2 in the first embodiment. The arrows in the figure represent the circulating flow through the endless channel 2.

[0017] (Biological treatment facility) The biological treatment equipment 1 in this invention is used in the oxidation ditch method, which performs biological treatment while circulating the water to be treated in an endless waterway 2. The water to be treated is not particularly limited, but examples include organic wastewater such as sewage, livestock wastewater, and factory wastewater. As shown in Figure 1A, the biological treatment facility 1 includes an endless channel 2 formed by a surrounding wall 21 and a partition wall 22, a vertical-axis aeration and stirring device 3 and a guide plate 7 installed in the endless channel 2.

[0018] The endless waterway 2 consists of two parallel straight waterways 2a and a circulating waterway 2b that connects the two straight waterways 2a at both ends to form a circulating flow of the treated material. In the first embodiment of the biological treatment facility 1, a vertical-axis type aeration and stirring device 3 is installed near the partition wall 22 of the straight waterway 2a, as shown in Figure 1A. Furthermore, as shown in Figure 1B, the vertical-axis aeration and stirring device 3 may be placed in the circulation channel 2b of the terminal channel 2.

[0019] The vertical-axis aeration and stirring device 3 performs surface aeration on the water to be treated in the flow path, supplying oxygen to the water. Furthermore, the vertical-axis aeration and stirring device 3, together with the nearby guide plate 7, forms a circulating flow in the endless channel 2. Specifically, the vertical-axis aeration and stirring device 3 generates an agitated flow within the water to be treated, and the nearby guide plate 7 guides this agitated flow, thereby forming a circulating flow in the endless channel 2.

[0020] (Vertical axis type aeration and stirring device) Figure 2 is a schematic diagram illustrating the structure of the vertical-axis aeration and stirring device 3 in this embodiment. As shown in Figure 2, the vertical-axis aeration and stirring device 3 includes an impeller 31 for aerating and stirring the water to be treated, and a drive unit 33 that supplies power to rotate the impeller 31. Furthermore, the impeller 31 in this embodiment includes a shaft 31C connected to the drive unit 33, a plurality of aeration blades 31A radially attached to the shaft 31C, and connecting plates 31B that connect the plurality of aeration blades 31A.

[0021] Furthermore, Figure 3A shows a perspective view of the impeller 31 of the first embodiment of the present invention, Figure 3B shows a plan view of the impeller 31 of the first embodiment of the present invention viewed from the axial direction, and Figure 3C shows a bottom view of the impeller 31 of the first embodiment of the present invention viewed from the axial direction. As shown in Figures 3A, 3B, and 3C, the connecting plate 31B is installed between it and the shaft 31C with a gap in between, and this gap forms a water passage hole 31D for pumping the water to be treated.

[0022] Next, we will explain the operation of the vertical-axis aeration and stirring device 3. As shown in Figure 2, the vertical-axis aeration and stirring device 3 is positioned with the water passage holes 31D in the water to be treated, and the tips of the aeration blades 31A are positioned above the water surface. When the impeller 31 is rotated in this position, the water to be treated, which is drawn in by the aeration blades 31A, is scattered into the surroundings as droplets from the tips of the aeration blades 31A due to centrifugal force. The guide plate 7, positioned near the vertical-axis aeration and stirring device 3, is positioned so that its upper end is near the water surface, allowing the droplets of the water to be treated to be scattered over the guide plate 7 and to a distant location. As the droplets of the water to be treated are scattered through the atmosphere, they take in air and land on the water to be treated while containing air. This allows oxygen to be supplied to the water to be treated.

[0023] When the water to be treated is scattered from the aeration blade 31A, the water to be treated flows in through the water passage hole 31D formed between the connecting plate 31B and the shaft 31C, allowing the water to be treated to be continuously scattered around the impeller 31.

[0024] Furthermore, multiple stirring blades 31E are installed radially on the shaft 31C in the water to be treated. The stirring blades 31E form an agitated flow in the water to be treated. The agitated flow is guided downstream by the guide plate 7, forming a circulating flow in the endless channel 2.

[0025] Next, we will describe the various parts of the impeller 31 in detail. <axis> As shown in Figure 2, shaft 31C is connected to the drive unit 33, and its purpose is to rotate the impeller 31 using power from the drive unit 33. The shape of the shaft 31C is not particularly limited, as long as it can rotate the impeller 31 using power from the drive unit 33. For example, it can be cylindrical or polygonal. The shaft 31C may also have a hollow structure with a hollow interior. In this case, the overall weight of the impeller 31 can be reduced while maintaining the strength of the shaft 31C, so that the water to be treated can be aerated and stirred with low power.

[0026] The material of the shaft is not particularly limited, but examples include metals such as iron or stainless steel, or resins such as hard plastics. From the viewpoint of strength and corrosion resistance, corrosion-resistant metals such as stainless steel are preferred.

[0027] As shown in Figure 2, the shaft 31C consists of multiple shafts and is equipped with a connecting section 31F that connects the multiple shafts. By making the shaft 31C divisible into multiple shafts, the position of the impeller 31 relative to the water depth of the water to be treated can be adjusted. For example, when installing the impeller 31 near the bottom of the water to be treated, the connecting section 31F can be divided and an extension shaft (not shown) can be added to extend the length of the shaft 31C.

[0028] Furthermore, as shown in Figure 2, a lifting device 31G may be provided. The lifting device 31G is a device for raising and lowering the impeller 31, and by providing the lifting device 31F, it becomes possible to finely adjust the height position of the impeller 31. By finely adjusting the height of the impeller 31, the amount of droplets formed by the impeller 31 and the scattering distance can be adjusted, thereby improving the oxygen supply efficiency to the water to be treated and further demonstrating the effects of the present invention, which reduces the power required for rotation.

[0029] <Aeration Wings> As shown in Figure 3A, the aeration blades 31A are formed above the connecting plate 31B for the purpose of scattering and aerating the water to be treated. The aeration blades 31A are also formed to extend radially outward from the shaft 31C, and their upper ends are bent in the direction of rotation of the impeller 31, with the curved portion O301 (described later) as the pivot point. Multiple aeration blades 31A are attached radially to the shaft 31C. The aeration blade 31A of the first embodiment is composed of blades 310A and 310B that are installed substantially parallel to the axial direction (substantially vertical direction) of the shaft 31C. The blade 310A guides the water to be treated, which has been scooped up by the blade 310A, radially outward along the blade 310A. Furthermore, by providing the blade 310B, the amount of water to be treated is scattered increases, which can further improve the oxygen supply efficiency. Furthermore, as shown in Figure 3B, the blades 310A (up to the dashed line) are fixed radially from the axis of the shaft 31C. Fixing the blades 310A radially from the axis makes it easier to balance the impeller 31 when it rotates.

[0030] As shown in Figures 3A and 3B, the blade 310B is bent with its upper end facing forward in the rotational direction of the impeller 31, using the curved portion O301 (described later) as a pivot point. As a result, the blade 310B is inclined upward toward the outside in the radial direction of the impeller from the axis 31C. Therefore, the treated water can be scattered over a long distance, thereby increasing the oxygen supply efficiency. The angle between the blade 310B and the water surface of the treated water is, for example, 10 to 80°, preferably 20 to 60°.

[0031] Furthermore, as shown in Figure 3C, the blade 310B may be bent at the tip portion on the outer side in the radial direction of the impeller, with the upper end of the blade 310A facing forward in the rotational direction of the impeller 31, using the curved portion O301 as a pivot point. According to this method, an aeration blade 31A with high aeration efficiency can be created with minimal processing, thereby significantly reducing the manufacturing cost and time of the impeller.

[0032] The number of aeration blades 31A is not particularly limited. Preferably, the number of aeration blades 31A is about 2 to 12, spaced equally apart when the impeller 31 is viewed from above. In this case, the water to be treated can be effectively stirred and dispersed into the atmosphere. More preferably, the number of aeration blades 31A is 6 to 8, spaced equally apart when the impeller 31 is viewed from above. In this case, the strength of the generated stirring flow and the amount of water to be treated dispersed into the atmosphere are optimized, so the water to be treated can be efficiently aerated and stirred.

[0033] Furthermore, as shown in Figures 3A and 3B, connecting plates 31B are connected between adjacent aeration blades 31A in the circumferential direction. Also, as shown in Figure 3G, the connecting plates 31B are fixed to the middle of the blade plate 310A and the stirring blade 31E, which will be described later. The blade plate 310B has the function of scattering the treated water, which is pumped up from the water passage holes 31D by the rotation of the impeller 31, around the impeller 31.

[0034] The material of the aeration blade 31A and the stirring blade 31E is not particularly limited, but examples include metals such as iron or stainless steel, or resins such as hard plastics. From the viewpoint of strength and corrosion resistance, corrosion-resistant metals such as stainless steel are preferred. Furthermore, the materials of the aeration blade 31A and the stirring blade 31E may be the same or different.

[0035] The shape of the aeration blade 31A is not particularly limited. For example, in the first embodiment, the plate surface of the blade 310A is installed approximately parallel to the axial direction (approximately vertical direction) of the shaft 31C, but the plate surface of the blade 310A may be fixed at an inclination with respect to the water surface.

[0036] <Song part O> As shown in Figure 3I(a), the curved portion O is the tip portion on the radially outer side, which acts as a pivot point that tilts the upper end of each aeration blade 31A toward the forward direction in the rotational direction of the impeller 31. The curved section O is only present at one location, O301, on the aeration blade 31A. This allows for a significant reduction in manufacturing costs and time for the impeller by performing minimal bending. Furthermore, it enables efficient dispersion of the treated water passing along the upper or lower surface of the connecting plate 31B into the atmosphere, and increases the amount of treated water dispersed, further improving oxygen supply efficiency. The angle between the blade 310B and the blade 310A at the curved section O301 is preferably 100 to 170°, and more preferably 110 to 160°. Furthermore, as shown in Figure 3I(b), instead of providing a specific curved section O, the upper end of the blade 310A may be inclined to curve gently overall toward the forward direction of rotation of the impeller 31. This allows the treated water passing along the upper or lower surface of the connecting plate 31B to be dispersed into the atmosphere more stably, and further improves the oxygen supply efficiency.

[0037] <Agitator blade> As shown in Figure 2, the stirring blades 31E are formed below the connecting plate 31B so as to be submerged in the water to be treated. Multiple stirring blades 31E are attached radially to the shaft 31C, forming an agitated flow in the water to be treated. Furthermore, as shown in Figure 2, the shape of the stirring blade 31E is such that its width increases from the outer end in the radial direction of the impeller toward the axis 31C. As a result, the stirring blade 31E becomes larger near the axis 31C, which is located inside the water to be treated, thus enabling the formation of a strong stirring flow in the water to be treated.

[0038] Figures 3D, E, and F show examples of the shape of the stirring blade 31E in this embodiment. As shown in Figures 3D, E, and F, the stirring blade 31E is formed radially outward from the radially outer side of the impeller 31. Furthermore, the stirring blade 31E is characterized in that, as shown in Figures 3D, E, and F, it is inclined or curved toward the rearward direction in the rotational direction of the impeller 31 compared to the aeration blade 31A. This feature allows for the aeration and stirring of the treated water with low power while maintaining the predetermined aeration performance of the aeration blades, thereby providing an impeller that effectively increases oxygen supply efficiency while saving energy. In other words, by using this impeller, it is possible to provide a water treatment device that effectively increases oxygen supply efficiency while saving energy.

[0039] In this invention, "inclined or curved toward the rear in the direction of rotation" means that, assuming that the starting points on the axial side of the stirring blade and the aeration blade (whose shape is compared) are at the same position, the radially outer endpoint of the stirring blade is located further rear in the direction of rotation than the radially outer endpoint of the aeration blade. Specific examples will be explained below with reference to Figures 3D, 3E, and 3F. Figure 3D shows a stirring blade 31E1 in which multiple straight plate materials are arranged so as to be inclined toward the rear in the direction of rotation of the impeller 31.

[0040] Here, in Figure 3D, we assume that the starting point P1 is the starting point of the aeration blade 31A on the axis 31C side, and the ending point P2 is the point on the radially outer side of the impeller where the aeration blade 31A contacts the connecting plate 31B. Furthermore, if the starting point on the axis 31C side of the stirring blade 31E1, which is adjacent to the aeration blade 31A in the rear direction of the impeller rotation, is set to the same position as the starting point P1 of the aeration blade 31A (shown by a dashed line in Figure 3D), then the ending point P3 of the stirring blade 31E1 is located further rearward than the ending point P2 of the aeration blade 31A in the direction of rotation of the impeller 31. In other words, Figure 3D shows that the stirring blade 31E1 is inclined such that its endpoint P3 is further rearward than the endpoint P2 of the aeration blade 31A relative to the rotational direction of the impeller 31.

[0041] According to the above features, by creating an impeller by arranging multiple straight plate materials, the manufacturing cost and time of the impeller can be significantly reduced compared to manufacturing an impeller by bending or curving the plate material. Furthermore, it becomes possible to efficiently agitate the water to be treated with low power while maintaining the predetermined aeration efficiency of the aeration blade.

[0042] Furthermore, as another example of the shape of the stirring blade 31E in this embodiment, Figure 3E shows a stirring blade 31E2 that is bent by a plurality of curved sections K301 to K303, which will be described later, and is arranged to tilt toward the rear in the rotational direction of the impeller 31. Here, in Figure 3E, we assume that the starting point P1 is the starting point of the aeration blade 31A on the axis 31C side, and the ending point P2 is the point on the radially outer side of the impeller where the aeration blade 31A contacts the connecting plate 31B. Furthermore, if the starting point on the axis 31C side of the stirring blade 31E2, which is adjacent to the aeration blade 31A at the rear in the direction of impeller rotation, is at the same position as the starting point P1 of the aeration blade 31A, then the endpoint P3 of the radially outer end of the stirring blade 31E2 on the impeller 31 is located further rearward in the direction of rotation of the impeller 31 than the endpoint P2 of the aeration blade 31A. Therefore, Figure 3E shows that the stirring blade is inclined such that the endpoint P3 of the stirring blade 31E2 is further rearward in the direction of rotation of the impeller 31 than the endpoint P2 of the aeration blade 31A.

[0043] <Music section K> As shown in Figure 3E, the curved section K is the pivot point that causes the stirring blade 31E2 to tilt in a specific direction. The curved sections K are multiple parts that incline the stirring blade 31E2 toward the rear in the rotational direction of the impeller 31. In Figure 3E, there are three curved sections, K301 to K303, but there are multiple curved sections and are not limited to these. For example, the number of curved sections K can range from two to ten per stirring blade 31E2. This significantly reduces the manufacturing cost and time of the impeller compared to manufacturing the stirring blade by bending a plate member to create a continuously curved shape, and allows for efficient stirring of the treated water with low power while maintaining the predetermined aeration efficiency of the aeration blade. Preferably, the number of curved sections K can range from three to five per blade 310A. This further significantly reduces the manufacturing cost and time of the impeller by performing minimal bending, and allows for efficient stirring of the treated water. The inclination angle of the blade portion 310A in each curved portion K301 to K303 is preferably 100 to 170°, and more preferably 110 to 160°.

[0044] Furthermore, as another example of the shape of the stirring blade 31E in this embodiment, Figure 3F shows a stirring blade 31E3 that does not have a specific curved section K and is curved overall toward the rear in the direction of rotation of the impeller 31. Here, in Figure 3F, we assume that the starting point P1 is the starting point of the aeration blade 31A on the axis 31C side, and the ending point P2 is the point on the radially outer side of the impeller where the aeration blade 31A contacts the connecting plate 31B. Furthermore, if the starting point on the axis 31C side of the stirring blade 31E3, which is adjacent to the aeration blade 31A at the rear in the direction of impeller rotation, is at the same position as the starting point P1 of the aeration blade 31A, then the endpoint P3 of the radially outer end of the stirring blade 31E3 on the impeller 31 is located further rearward in the direction of rotation of the impeller 31 than the endpoint P2 of the aeration blade 31A. Therefore, Figure 3F shows that the stirring blade is curved such that the endpoint P3 of the stirring blade 31E3 is located further rearward in the direction of rotation of the impeller 31 than the endpoint P2 of the aeration blade 31A.

[0045] As exemplified by the impeller blades 31E1 to 31E3, in this invention, "inclined or curved toward the rear in the direction of rotation" means that the impeller blade is inclined or curved such that the endpoint P3 of the impeller blade is located further rearward than the endpoint P2 of the aeration blade with respect to the direction of rotation of the impeller 31.

[0046] <Connecting plate> As shown in Figure 3A, the connecting plate 31B is fixed to the aeration blade 31A with a gap between it and the shaft 31C, and this gap forms a water passage hole 31D through which the water to be treated passes.

[0047] As shown in Figure 3G, the connecting plate 31B is installed at an angle in the VV direction of Figure 3B, following the shape of the aeration blades 31A and stirring blades 31E, from the water passage hole 31D toward the outer diameter of the impeller. This allows the treated water passing along the upper or lower surface of the connecting plate 31B to be efficiently dispersed into the atmosphere.

[0048] Furthermore, in another configuration of the connecting plate 31B, the connecting plate 31B may be installed such that the angle of inclination from the outer circumference toward the water passage hole 31D increases toward the adjacent aeration blade 31A in the direction of rotation forward from the blade portion 31A. That is, the position indicated by the star in Figure 3B is the lowest position. This makes it possible to efficiently draw the water to be treated from the water passage hole 31D to the aeration blade 31A by scooping it up from the position indicated by the star in Figure 3B. The flow of the scooped-up water to be treated is shown by the arrow.

[0049] Furthermore, as another embodiment of the connecting plate 31B, as shown in Figure 3H, in the VV direction of Figure 3B, the connecting plate 31B may be further inclined upward from the water passage hole 31D toward the outer diameter of the impeller. This makes it possible to efficiently guide the water to be treated, drawn up from the water passage hole 31D, toward the upper end of the upper part 311 of the blade, and to disperse the water to be treated into the atmosphere even more efficiently.

[0050] As shown in Figure 3I(a), the connecting plate 31B connects the blades 310A of adjacent aeration blades 31A in the VV direction in Figure 3G in a flat manner. Furthermore, as another embodiment of the connecting plate 31B, as shown in Figure 3I(b), the connecting plate 31B may be connected such that adjacent aeration blades 31A in the VV direction of Figure 3G are inclined downwards in Figure 3I(b) toward the direction of rotation of the impeller. This makes it possible to efficiently draw the water to be treated from the water passage hole 31D to the aeration blades 31A.

[0051] The connecting plate 31B is formed from a plate member, and its material is not particularly limited, but examples include metal such as iron or stainless steel, or resin such as hard plastic. From the viewpoint of strength and corrosion resistance, corrosion-resistant metals such as stainless steel are preferred.

[0052] The shaft 31C, aeration blade 31A, connecting plate 31B, and stirring blade 31E may be connected as separate components or formed as a single unit.

[0053] (Guide board) As shown in Figure 1A, the guide plate 7 is intended to rectify the agitated flow generated by the impeller 31 of the vertical-axis aeration and stirring device 3 when the vertical-axis aeration and stirring device 3 is positioned in the straight channel 2a, thereby agitating and circulating the water to be treated in the terminal channel 2. It is fixed to the partition wall 22 so as to cover the upstream side of the vertical-axis aeration and stirring device 3. As shown in Figure 2, the guide plate is installed with its upper end approximately at the water surface to be treated and its lower end at the same height as, or slightly above, the lower end of the vertical-axis aeration and stirring device. By positioning the upper end of the guide plate approximately at the water surface, the spray scattered by the rotation of the impeller 31 lands on the surrounding water, thereby improving oxygen supply efficiency. It also excels at eliminating floating scum. Furthermore, by positioning the lower end of the guide plate at the same level as the lower end of the vertical-axis aeration and stirring device, the agitated flow generated by the rotation of the impeller 31 can be guided to a predetermined position. Furthermore, as shown in Figure 1B, when the vertical-axis aeration and stirring device 3 is placed in the circulating water channel 2b, the surrounding wall 21 near the circulating water channel 2b functions similarly to the guide plate 7, so it is not necessary to provide the guide plate 7.

[0054] [Second Embodiment] Figures 4A and 4B are perspective and cross-sectional views, respectively, showing the structure of the impeller 41 in the second embodiment. The following will provide a detailed explanation using the drawings. Note that the shaft 41C, connecting plate 41B, and water passage hole 41D are the same as the shaft 31C, connecting plate 31B, and water passage hole 31D in the first embodiment, so their explanation will be omitted.

[0055] <Wing section> The impeller 41 in the second embodiment differs from the various impellers 31 in the first embodiment in that, as shown in the shaded area of ​​Figure 4A, the radial tip portion of each blade 410A in each aeration blade 41A extends downward from the connecting plate 41B. The other blades 410B, stirring blades 41E, and curved sections K401 to K403 are the same as those in the first embodiment, so their description is omitted.

[0056] In the second embodiment, the blade 410A is formed by extending the radial tip portion of each blade 410A of each aeration blade 41A downward from the connecting plate 41B, as shown in the shaded areas of Figures 4A and 4B. According to this, even if the rotation speed of the impeller is increased, it becomes possible to further increase the amount of treated water scattered in a more stable manner, thereby further improving the oxygen supply efficiency. Furthermore, the blade 410A may be joined to the end of the stirring blade 41E, as shown in Figure 4B. In this configuration, the extended portion of the blade 410A receives the water to be treated, which is stirred by the stirring blade 41E and moves radially along the lower surface of the connecting plate 41B. This allows a strong centrifugal force to be applied to the water to be treated, enabling efficient dispersion of the water and further improving aeration efficiency.

[0057] [Third Embodiment] Figures 5A and 5B are perspective and cross-sectional views, respectively, showing the structure of the impeller 51 in the third embodiment. The following will provide a detailed explanation using the drawings. Note that the shaft 51C, connecting plate 51B, and water passage hole 51D are identical to the shaft 31C, connecting plate 31B, and water passage hole 31D in the first embodiment and the shaft 41C, connecting plate 41B, and water passage hole 41D in the second embodiment, so their explanation will be omitted.

[0058] <Wing section> The impeller 51 in the third embodiment differs from the various impellers 31 and 41 in the first and second embodiments in that, as shown in Figure 5A, the radial tip portion (shaded portion) of each blade 510A in each aeration blade 51A extends downward from the connecting plate 51B, and is inclined toward the rear in the rotational direction of the impeller 51 at the curved portion 502, which will be described later. The other blades 510B, stirring blades 51E (not shown), and curved portions K501 to K503 (not shown) are the same as the blades 310B, stirring blades 31E, and curved portions K301 to K303 in the first embodiment, and the blades 410B, stirring blades 41E, and curved portions K401 to K403 in the second embodiment, so their description is omitted.

[0059] <Song part O> As shown in Figure 5B, the curved portion O502 is the tip portion on the radially outer side, which acts as a pivot point that tilts the tip of each aeration blade 51A toward the rear in the rotational direction of the impeller 31. The angle between the inclined tip portion and the straight portion of the aeration blade 51A in the curved portion O501 is, for example, preferably 100 to 170°, and more preferably 110 to 160°. Alternatively, instead of providing a specific curved section O502, the tips of each aeration blade 51A may be inclined to curve gently towards the rear in the direction of rotation of the impeller 31.

[0060] In the third embodiment, as shown in the shaded area of ​​Figure 5A, the impeller blade 510A has the radial tip portion of each blade 510A of each aeration blade 51A extended downward from the connecting plate 51B, and the curved portion 502 is inclined toward the rear in the rotational direction of the impeller 51. This increases the amount of treated water scattered while suppressing the resistance from the treated water to the rotation of the impeller, thus providing an impeller that is energy-saving and has high oxygen supply efficiency.

[0061] [Fourth Embodiment] Figures 6A to 6G are plan views, bottom views, front views, rear views, left side views, right side views, and perspective views, respectively, showing the shape of the impeller in the fourth embodiment. In Figures 6A to 6G, the dashed lines represent the shape of the shaft portion of the impeller in this embodiment. The solid lines represent the shape of the blade portion and connecting plate of the impeller in this embodiment, excluding the shaft portion. The shape of the shaft portion of the impeller in this embodiment may be anything. For example, cylindrical or polygonal prism shapes are possible.

[0062] In the fourth embodiment, the impeller is placed inside the water treatment tank and rotates with an axial direction substantially perpendicular to the surface of the water to be treated, that is, a direction intersecting the surface of the water, to aerate and stir the water to be treated.

[0063] [Fifth Embodiment] Figures 7A to 7G are plan views, bottom views, front views, rear views, left side views, right side views, and perspective views, respectively, showing the shape of the impeller in the fifth embodiment. In Figures 7A to 7G, the dashed lines represent the shape of the shaft portion of the impeller in this embodiment. The solid lines represent the shape of the blade portion and connecting plate of the impeller in this embodiment, excluding the shaft portion. The shape of the shaft portion of the impeller in this embodiment may be anything. For example, cylindrical or polygonal prism shapes are possible.

[0064] In the fifth embodiment, the impeller is placed inside the water treatment tank and rotates with an axial direction substantially perpendicular to the surface of the water to be treated, that is, a direction intersecting the surface of the water, to aerate and stir the water to be treated.

[0065] The embodiments described above are examples of impellers for aeration and stirring devices. The impeller according to the present invention is not limited to the embodiments described above, and the impeller according to the embodiments described above may be modified without changing the gist of the present invention.

[0066] For example, two aeration blades, stirring blades, and connecting plates may be installed vertically on the same axis. This allows the impeller located at the bottom to be completely submerged in the water to be treated, thereby agitating the water, while the impeller located at the top can disperse the water into the atmosphere. As a result, the agitation force can be improved while maintaining aeration efficiency.

[0067] Furthermore, the structure may be designed so that the angle of the aeration blade or stirring blade with respect to the axis, and the angle of the aeration blade, stirring blade and connecting plate with respect to the axis, can be easily changed after the impeller is installed. In this case, the shape of the impeller can be easily changed on-site to achieve the optimal aeration and stirring capacity in response to the viscosity of the water to be treated. [Industrial applicability]

[0068] The impeller of the present invention can be suitably used in vertical-axis aeration and stirring devices for biological water treatment facilities. [Explanation of symbols]

[0069] 1 Biological treatment equipment, 2 Endless waterway, 2a Straight waterway, 2b Circulating waterway, 21 Surrounding wall, 22 Compartment wall, 3 Vertical axis aeration and stirring device, 31 Impeller, 31A, 41A, 51A Aeration blade, 31B, 41B, 51B Connecting plate, 31C, 41C, 51C Shaft, 31D, 41D, 51D Water passage hole, 310A, 310B, 410A, 410B, 510A, 510B Blade, 31E, 41E Stirring blade, 31F Connecting section, 31G Lifting device, 33 Drive unit, 7 Guide plate, 301~303, 401~403 Curved section K, 301, 401, 501, 502 Curved section O, P1 Starting point, P2, P3 Ending point

Claims

1. An impeller that aerates and / or stirs the water to be treated, The axis and A plurality of aeration blades for aerating the water to be treated, A stirring blade for stirring the water to be treated, The system comprises a connecting plate spaced apart from the shaft and positioned between the plurality of aeration blades, The aeration blade and the stirring blade are each formed radially outward, The aeration blade is positioned on one side of the connecting plate, and the stirring blade is positioned on the opposite side of the connecting plate. An impeller characterized in that the stirring blades are inclined or curved toward the rear in the direction of rotation of the impeller compared to the aeration blades.

2. The impeller according to claim 1, characterized in that the stirring blade is inclined toward the rear in the direction of rotation of the impeller from the aeration blade by bending a planar plate at multiple locations.

3. The impeller according to claim 1, characterized in that the upper end of the aeration wing is bent or curved toward the direction of rotation.

4. The impeller according to claim 2, characterized in that the upper end of the aeration blade is bent or curved toward the direction of rotation.

5. An impeller attached to a stirring device for aerating and / or stirring water to be treated, The axis and An aeration blade for aerating the water to be treated is positioned axially above the aforementioned shaft, The system includes a stirring blade positioned axially below the shaft for agitating the water to be treated, The aeration blade and the stirring blade are each formed radially outward, The impeller is characterized in that the stirring blades are inclined or curved toward the rear in the direction of rotation of the impeller compared to the aeration blades.

6. A stirring device characterized by comprising an impeller according to any one of claims 1 to 5.

7. A water treatment method using the stirring device described in claim 6.

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