Mixing device for mixing liquids in a mixing tank

Inside a driven cylindrical housing 23 that is a cylindrical rotation member 13, a liquid to be mixed 4 is caused to become an inner circulation current f by extruded plate portions 24A-24D. Discharge ports 22A-22D formed in the cylindrical housing 21 discharge a portion of the inner circulation current f outward as outer discharge current d1-d4 by centrifugal force. At the same time, the outer portion of the liquid to be mixed 4 is sucked into suction ports 23, 30 as suction current e1-e3, h1-h4, thus mixing the liquid to be mixed 4 in the mixing tank 3.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to JP 2012-280988, filed on Dec. 25, 2012, entitled “Mixing Device”, which are herein incorporated by reference for all purposes.

TECHNICAL FIELD

The present invention relates to a mixing device and more particularly to a mixing device that can enhance mixing capabilities for mixing liquids in a mixing tank.

BACKGROUND

Conventional mixing devices were structured such that an impeller-type mixing member was attached to a shaft (See patent documents 1 and 2).

In contrast, certain mixing devices do not have the configuration of impeller blades being attached to a mixing member. A cross-section of a circular shaped mixer body, as described in Patent Document 3, proposes a structure in which flow passages link inlet ports and outlet ports so as to blend two or more fluids, uniformly disperse powder added to a fluid, and to avoid damage and fluid contaminants associated with impeller blade mixing operation.

PRIOR ART DOCUMENTS

Patent Document

SUMMARY

Problems to be Solved by the Invention

In consideration of the above points, the present invention proposes a non-impeller-type mixing device with an improved mixing function so that dangers associated with operating an impeller blade-type mixer and the disadvantage of hazardous objects entering into the fluid being mixed can be overcome.

Means for Solving the Problem

In order to solve the problem, the present invention provides a mixer body5that rotates around the center axis line L1of a cylindrical housing21which is a cylindrical rotating member13via a rotating drive shaft11connected to a top plate13A that encloses the upper end of the cylindrical housing21. The cylindrical rotating member13has a plurality of discharge ports22A-22D formed in the peripheral surface of the cylindrical housing21. Provided at the inner peripheral surface of the cylindrical housing21are a plurality of inwardly, projecting extruded plate portions24A-24D. Provided at the bottom end of the cylindrical housing21is a suction port23,30. When the cylindrical rotating member13rotates, the extruded plate portions24A-24D cause an inner circulation current fin which the liquid to be mixed4circulates around the center axis line L1. A portion of the liquid to be mixed4, that forms the inner circulation current f, is discharged outwardly, as outer discharge current d1-d4, by centrifugal force through discharge ports22A-22D. At the same time, the liquid to be mixed4that is outside the cylindrical rotating member13is sucked into the cylindrical rotating member13as suction current e1-e3, h1-h4via suction ports23,30.

Effects of the Invention

According to the present invention, inside the cylindrical housing, which acts as a cylindrical rotating member, are extruded plate portions that cause an inner circulation current of the liquid to be mixed when the cylindrical housing is rotated. Centrifugal force discharges a portion of the inner circulation current outwardly via discharge ports provided in the cylindrical housing. At the same time, liquid to be mixed that is outside the cylindrical housing is drawn therein as suction current via suction ports thus mixing the liquid in the mixing tank.

DETAILED DESCRIPTION

(1) First Embodiment

InFIG. 1, a mixing device1as a whole is illustrated in which a mixer body5having a cylindrical shape, is inserted vertically from the top of the liquid mixing portion2having a quadrate configuration, into the liquid mixing reservoir3that is filled with liquid to be mixed4.

The mixer body5extends vertically from a rotation drive portion10and is attached to a lower end of a rotating drive shaft11. The rotating drive shaft11extends vertically and is driven by rotation drive portion10around a center axis line L1.

As shown inFIG. 2, the mixer body5has a cylindrical rotating member13in which the upper and lower surfaces of the respective top plate13A and bottom plate13B block the cylindrical rotating member13. As shown by arrow a, when the rotation drive shaft11, the lower end of which is integrally fixed to the top plate13A, is rotated counter-clockwise, the cylindrical rotating member13rotates counter-clockwise as shown by arrow b.

The rotating member13, to which the upper surface and lower surface of the respective top plate13A and bottom plate13B are attached, has a cylindrical housing21made of a thin sheet of metal. In the outer surface of the cylindrical housing21, as shown inFIG. 3, 4 discharge ports22A-22D are formed at 90 degree angles around the center of the center axis line L1. At the same time, a suction tube23, which communicates with the cylindrical housing21and has the function of being a suction port, protrudes downward from the center of the bottom plate13B.

In this embodiment, the arrangement of the discharge ports22A-22D is that they are formed vertically at intermediate positions in two levels in the cylindrical housing21. Accordingly, there are 8 discharge ports formed in the cylindrical outer peripheral surface of the cylindrical rotating member13at 90 degree intervals.

At the end edges of the discharge ports22A,22B,22C and22D of the cylindrical housing21at the rotation direction b side, extruded plate portions24A,24B,24C and24D are formed in the direction toward the central axis line L1side. Accordingly, when the cylindrical housing21containing the liquid to be mixed4is rotated in the rotation direction b, the liquid to be mixed4is forced out by the extruded plate portions24A,24B,24C and24D through discharge ports22A,22B,22C and22D to which said extruded plate portions24A,24B,24C and24D are adjacent thereto.

According to the above configuration, when the mixer body5has been inserted into the liquid to be mixed4and rotated by the rotation drive portion10in the direction of arrow a, the space between the extruded plate portion24A of the discharge port22A and the extruded plate portion24B of discharge port22B, the space between the extruded plate portion24B of discharge port22B and the extruded plate portion24C of discharge port22C, the space between the extruded plate portion24C of discharge port22C and the extruded plate portion24D of discharge port22D and the space between the extruded plate portion24D of discharge port22D and the extruded plate portion24A of discharge port22A at the circumferential surface of the cylindrical housing5, moves in the same direction as arrow a as is illustrated by arrows c1, c2, c3and c4.

At this time, as the above mentioned portions each move in the direction of c1, c2, c3and c4, a portion of the liquid to be mixed4inside the cylindrical housing21comes in contact with the center portion of the cylindrical housing21and is drawn along by the movement.

From this, after the cylindrical rotation member13starts rotating and a stable rotation state is attained, the rotation operation draws along the liquid to be mixed4at the extruded plate portions24A-24D. The rotation speed of the liquid to be mixed4around the center axis line L1is the same rotation speed of the rotation drive shaft11(This is called inner circulation current f.).

The outer side of the liquid to be mixed4, that forms the inner circulation current f, is drawn along by the rotation. The liquid to be mixed4centered around then central axis line L1is dispersed outward by centrifugal force.

In due course, a portion of the inner circulation current f of the liquid to be mixed4that has been acted upon by centrifugal force, is discharged, as shown by arrows d1-d4inFIG. 3, as an outer discharge current from discharge ports22A-22D of the cylindrical housing21to the outer parts of the mixing tank3.

With this embodiment, when discharge ports22A-22D are punched in the outer circumference of the metal sheet portion of the cylindrical housing21, plate members are positioned at the outer circumferential edge of the discharge ports22A-22D forming a gap. These plate members are folded inward after machining to form extruded plate portions24A-24D.

In that case, if the fold angle33F relative to the inner side surface of the cylindrical housing21is, for example 45 degrees and if the cylindrical rotation m ember13is rotated, the extruded plate portions24A-24D push the liquid to be mixed4in direction of the center axis line L1. In this way, the inner circulation current f forming operation can be easily carried out by the extruded plate portions24A-24D.

At this time, only the portion of the liquid to be mixed4inside the cylindrical housing21that was dispersed as an outer discharge current d1-d4is subject to negative pressure. As a result and as shown inFIG. 2, of the liquid to be mixed4that is inside the mixing tank3, and the liquid to be mixed4around the suction tube23, which serves as a suction port, is drawn there-through as illustrated by arrow e1into the cylindrical housing21as suction current. Accordingly, as shown by arrows e2and e3, liquid to be mixed4that is near the bottom plate3A of the mixing tank3is gathered at the lower end of the suction tube23and drawn there-though as suction current e1.

At the time of this flow of the liquid to be mixed4that is inside the cylindrical housing21, the outer discharge current d1-d4is discharged from the discharge ports22A-22D at the same time that suction current e1-e3occurs from the suction tube23. As a result, the liquid to be mixed4that is drawn into the suction tube23and after the inner circulation current f centers around the central axis line L1of the cylindrical housing21, a portion of the inner circulation current f is discharged outward as an outer discharge current d1-d4to become a mixing current of the liquid to be mixed4.

With the above configuration, the rotation of the cylindrical member13causes the occurrence of inner circulation current f therein. At the same time, centrifugal force causes a portion of the liquid to be mixed4, as outer discharge current d1-d4, to go against the current. In addition, negative pressure is used to draw liquid4in the mixing tank3into the cylindrical housing and around the cylindrical rotating member13, as indicated by the suction current e1-e3. The cylindrical rotating member13stirs and mixes the liquid. This produces a homogenized liquid in the mixing tank.

As the liquid to be mixed4as a whole can be engulfed in the mixing current, even if the mixing tank3is cylindrical or a quadrate or other shape, a uniform mixture can be made.

Actually, the discharge power of the outer discharge current d1-d4and the suction power of the suction current e1-e3can be controlled by appropriately determining the RPM of the cylindrical rotation member13thus enhancing the mixing function. In this way, the type of mix needed for the mixing tank3, for example a gentle mix when a liquid to be mixed4is of low viscosity or a strong mix when a liquid to be mixed has a high specific gravity ratio or viscosity, can be determined.

In addition, in order to clean the mixer body5, one simply needs to replace the liquid to be mixed4in the mixing tank, with a cleaning liquid (e.g. clean washing water, methanol, etc.) and perform the foregoing mixing operation. Thereafter, the spent mixing liquid is discarded thus obtaining a practical, sufficient cleaning.

(2) Second Embodiment

AsFIG. 4illustrates a second embodiment of the mixing device1, the same symbols as shown inFIG. 2for corresponding elements will be used.

In the case ofFIG. 4, intake ports25A,25B,25C and25D are formed in the upper plate13A of the cylindrical rotation member13at 90 degree angles at equal intervals around the central axis line L1so that liquid to be mixed4that is above the cylindrical rotation member13is drawn into the cylindrical rotation member13through the above mentioned intake ports25A-25D.

Regarding the configuration inFIG. 4, the same symbols as shown inFIG. 1for corresponding elements inFIG. 5will be used. When the mixer body5that is inserted into the liquid to be mixed4in the mixing tank3is rotated by the rotation drive portion10, as indicated inFIG. 2andFIG. 3above, an inner circulation current f is formed around the center of the center axis line L1by the function of the extruded plate portions24A-24D of the cylindrical rotation member13of the housing21. At the same time, an outer discharge current d1-d4is formed from the above mentioned inner circulation current f passing through the discharge ports22A-22D. From this, suction current e1-e3occurs at the lower end of the suction tube23.

At this time, an inner circulation current f is generated inside the cylindrical housing21by the occurrence of a discharge current d1-d4causing a negative pressure to the liquid to be mixed4that is above the discharge ports22A-22D of the cylindrical housing21. As a result, the liquid to be mixed4above the upper plate13A is drawn into the cylindrical rotation member13, as indicated by arrows g1-g4, as a suction current.

At the same time that a suction current e1-e3is being formed at the lower portion of the cylindrical rotation member13that is inside the mixing tank3, an intake current g1-g4is formed at the upper part of the cylindrical rotation member13via intake ports25A-25D.

In this case, because the intake current g1-g4occurs in the vicinity of the surface of the liquid to be mixed4and serves as a water surface interface, the mixer body5is able to intermix air into the liquid to be mixed4thus forming bubbles at the liquid surface because the mixing function draws air therein. (This is called aerobic mixing.)

In relation to this, in the cases of the above-mentionedFIGS. 1 to 3, bubbles are not formed on the liquid surface as the mixing function does not draw air therein. (This is called anaerobic mixing.)

AsFIG. 6illustrates a third embodiment, the same symbols as shown inFIG. 2for corresponding elements will be used.

The configuration of the mixing device1according to this embodiment, is that the suction tube23and the lower plate13B of the cylindrical rotation device13ofFIG. 2, have been omitted.

As a result, the bottom of the cylindrical rotation member13is a cylindrical shaped communication hole30, the diameter of which corresponds to the diameter of the cylindrical housing21. The same symbols as shown inFIG. 1for corresponding elements will be used forFIG. 7. Regarding this wide communication hole30, the liquid to be mixed4in the area between the communication hole30and the bottom plate3A of the mixing tank3is circulated by the sucking in of a large amount of liquid to be mixed4from around the communication hole30as suction current h1-h4and then as outer discharge current d1-d4. In particular, a thorough mixing of the liquid to be mixed4at the bottom of the mixing tank can be performed.

In this case, if the cylindrical rotation member13is set so that the space between the bottom plate3A of the mixing tank3and the bottom edge of the cylindrical rotation member13of the mixer body5is narrow, a strong suction strength of the mixing device1, with respect to the liquid to be mixed4around the periphery of the bottom plate3A of the mixing tank3, can be obtained.

(4) Other Embodiments

(4-1) The anaerobic mixing embodiments such as inFIGS. 1-3andFIGS. 6-7have numerous applications. While not limited in scope to this particular application, the mixing device1is ideal to use in a mixing tank when high precision is required such as that of an elution testing device for drugs.

In particular, when aerobic mixing inFIG. 4-FIG. 5is included, the inner circulation current f formed inside the cylindrical rotation member13is acted upon by centrifugal force causing the outer discharge current d1-d4to split forming a relatively simple flow passage. From this, thorough mixing can be made even if the liquid to be mixed4is of high viscosity or contains particles such as a liquid to be mixed at a sewage treatment facility.

(4-2) Regarding the above embodiments, the case was discussed where the cylindrical rotation member13has discharge ports22A-22D, each having an extruded plate24A-24D, formed vertically therein at two levels. However, the number of vertical levels formed is not limited to 2. There can be more than two levels and there can be more than 2 discharge ports in one level. The point is that these configurations obtain the same effect as above since an inner circulation current f is formed at the central axis line and centrifugal force creates a plurality of outer discharge currents via discharge ports.

(4-3) Regarding the embodiments discussed above, the cylindrical housing21is made of a thin sheet of metal into which discharge ports22A22D are cut in the outer surface forming a gap. The plate portions are folded inward at 45 degrees to form extruded plate portions24A-24D. However, the fold angle33F may be other than 45 degrees and the shape of the extruded plate portions24A-24D may be adjusted to more easily form an inner circulation current.

(4-4) In addition, the vertical positioning relationship of the discharge ports22A-22D and the extruded plate portions24A-24D may be changed from one in which the heights are the same to one in which they are mutually shifted. In other words, it is sufficient as long as an inner circulation current f is formed inside the cylindrical rotation member13by the movement of the extruded plate portions24A-24D and a portion of the inner circulation current f is discharged via discharge ports22A-22D by centrifugal force.

(4-5) Regarding the embodiments ofFIGS. 1-3andFIGS. 6-7, the rotation drive shaft11was of a rod-like shape. However, a pipe shaped rotation drive shaft11may be applied in which air bubbles may be introduced into the mixing tank3via the hollow portion of the rotation drive shaft11, thereby providing an aerobic mix.

In this case, the pipe shaped rotation drive shaft11is configured so that the upper end is above the liquid to be mixed4so as to discharge air. This causes a negative pressure to occur inside the cylindrical housing21when a portion of the inner circulation current f is discharged outward as an outer discharge current d1-d4. Air is thus mixed into the liquid to be mixed4that is inside the cylindrical housing21via the hollow portion of the rotation drive shaft11.

Thus, a mixing device that enables aerobic mixing can be achieved.

In this way, when the rotation drive shaft11is in the shape of a pipe, the length of the pipe does not have to stop at the upper plate13A but can pass through the upper plate13A and into the cylindrical housing21.

When applied to the embodiments inFIG. 6-FIG. 7, this pipe shaped rotation drive shaft11can pass through the length of the cylindrical housing21.

INDUSTRIAL APPLICABILITY

The present invention can be used for mixing a liquid to be mixed in a mixing tank.

EXPLANATION OF CODES