JP2009279529A - Agitation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agitation apparatus which agitates the content of a treatment tank with a smaller agitation device than the conventional efficiently while controlling the agitation power to the same degree as the usual and which has a high maintenance mechanism capable of conducting the continuous operation as usual while controlling the manufacturing cost. <P>SOLUTION: An agitation unit 40 is provided with: a rotation driving part 42 held by a retention unit 20; a drive shaft 44 rotating by the drive of the rotation driving part 42 extended to the inside of the treatment tank TK from the rotation driving part 42; an axial flow impeller 45 located in a draft tube 30 fitted to the leading edge of the drive shaft; and a supporting tube 50 through which the drive shaft 44 is penetrated. A first bearing 51 and a second bearing 52 to hold the drive shaft 44 respectively so that it is rotatable are fitted to the base 41 side of the supporting tube 50 and the leading edge side. Among these, the second bearing 52 is held to the horizontal direction in the treatment tank by the retention unit 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an agitation device used for purification treatment of liquids to be treated such as sewage such as sewage and human waste and sludge.

  As a method of stirring a liquid to be treated such as sewage stored in a treatment tank, a method of stirring using a pump and a stirring method using a machine that performs stirring by rotating an impeller are known. Here, FIG. 17 shows an example of a conventional mechanical stirring device shown in Patent Documents 1-4, for example. In FIG. 17, the mechanical stirring device 1 includes a holding unit 1 </ b> A, a draft tube 10 that is a cylindrical housing held by the holding unit 1 </ b> A in the treatment tank TK, and a liquid to be treated in the draft tube 10. And a stirring unit 1B that is detachably held by a holding unit 1A that forms a counterflow.

  The holding unit 1 </ b> A includes a gantry 7 and a support column 8. The stirring unit 1 </ b> B is coaxially mounted in a motor 2, a drive shaft 5 rotated by the motor 2, and a draft tube 10 attached to the tip of the drive shaft 5. And an axial flow impeller 6 disposed at the same position. Further, the draft tube 10 is provided with guide vanes 11 arranged coaxially below the axial flow impeller 6. When the axial flow impeller 6 rotates and a downward flow is formed in the draft tube 10, the liquid to be processed is transferred from the surface layer to the bottom, forming a large circulating flow in the processing tank TK, The whole liquid to be treated is stirred.

  Here, the drive shaft 5 of the stirring unit 1B is cantilevered only by the bearing 4 on the gantry 7. For this reason, a turbulent flow is generated at the stagnation mouth portion of the draft tube 10 as the axial flow impeller 6 rotates, and the load fluctuation that the axial flow impeller 6 receives from the liquid to be treated increases, and the axial flow impeller 6 vibrates in the radial direction. It becomes easy to do.

Therefore, in Patent Document 1, as shown in FIG. 18, an annular groove 32 is provided around the axial flow impeller 6 to prevent the axial flow impeller 6 from coming into contact with the draft tube 10 when it vibrates in the lateral direction. is doing. The depth of the annular groove 32 in the radial direction is usually about 0.05D (D: impeller diameter). Further, the annular groove 32 has an axial flow due to a swing of the axial flow impeller 6 due to the eccentricity of the shaft warpage, a lateral shake due to the natural vibration of the rotating body axial flow impeller 6 and the drive shaft, and a roll due to the natural vibration of the holding unit 1A. It also has a role of avoiding contact between the impeller 6 and the draft tube 10. Moreover, the axial-flow impeller 6 of the stirring aeration apparatus which aerobically treats the wastewater etc. which are disclosed by patent documents 2-4 with activated sludge is used for the axial-flow impeller 6 used for the above-mentioned stirring system.
Japanese Patent Publication No.53-10281 Japanese Patent No. 3239170 Patent No. 3239171 Patent No. 3239172

  By the way, in the mechanical stirrer 1 described above, the axial flow impeller 6 is required to be downsized in order to reduce manufacturing cost and vibration / noise. In order to reduce the size of the axial flow impeller 6 while maintaining the amount of water flow for proper stirring, it is necessary to increase the rotational speed of the axial flow impeller 6 to increase the water flow rate.

  However, in the case of a stirring device that cantilever-drives the drive shaft 5 as shown in Patent Documents 1-4, the impeller 6 swings around and the impeller 6 drives the drive shaft as the shaft bends due to eccentricity of the shaft or rotating centrifugal force. It is necessary to avoid vibration caused by resonance between the natural vibration of the column and the natural vibration of the column 8 -draft tube 10 and the turbulent flow of the suction flow. For this reason, it is necessary to operate at a specific rotational speed or less, and there is a problem that it is difficult to operate at the rotational speed necessary for downsizing.

  Therefore, an object of the present invention is to provide a stirring device that can reduce vibration of an axial impeller and reduce the size of the device.

  The stirring device of the present invention includes a holding unit attached to an upper part of a processing tank containing a processing liquid, a stirring unit for stirring the processing liquid in the processing tank held by the holding unit, In the agitation device provided with the draft tube held by the holding unit so as to be positioned at the position, the agitation unit includes a base that is held by the holding unit, a rotation drive unit provided on the base, and a rotation drive unit A drive shaft that is rotated by driving a rotary drive unit that extends into the processing tank, a support cylinder that is fixed to the base and through which the drive shaft passes, and a draft attached to the tip of the drive shaft that protrudes from the support cylinder An axial flow impeller located in the tube, a first bearing rotatably holding a drive shaft attached to the base side of the support cylinder, and a drive shaft attached to the distal end side of the support cylinder are rotatably held. , Is characterized in that the holding unit in which a second bearing which is supported with respect to the horizontal direction in the sense tank.

  The stirring unit may be any unit that is held by the holding unit, and may be fixed to the holding unit, but is preferably detachably attached.

  Further, the holding unit is not limited in its configuration as long as it holds the stirring unit and the draft tube. For example, the holding unit is attached to the upper part of the processing tank and has an opening into which the stirring unit is inserted. There may be provided a support member that supports the draft tube at the tip that extends inward, and a bearing support portion that supports the second bearing fixed to the support member in the horizontal direction.

  Further, if the second bearing is supported in the horizontal direction by the holding unit, regardless of the support method, the second bearing is accommodated in an annular member attached to the tip of the support cylinder, for example. The bearing support portion may have an annular frame body into which the annular member is fitted, or when the second bearing is accommodated in the support cylinder, the second bearing is indirectly held by holding the support cylinder. It may also be one that is retained.

  In particular, the annular member has a conical shape in which the diameter decreases from the upper part to the lower part, and the bearing support part protrudes from the annular frame toward the center of the annular frame, and is an inclined surface that contacts the side surface of the annular member It may have a protruding member on which is formed.

  The support member includes an upper support column that is not submerged in the liquid to be processed in which a bearing support portion is provided near the water surface, and a lower support column that is submerged in the process liquid connected to the upper column. Also good. At this time, the upper support column may be composed of a rod-shaped support column or a column column formed in a cylindrical shape.

  Furthermore, the arrangement height of the draft tube in the treatment tank is appropriately set, but the distance between the upper end of the draft tube and the maximum water level position of the liquid to be treated in the treatment tank is the rotational speed of the axial impeller. It is preferable that the draft tube is disposed in the liquid to be treated so that the distance increases as the height increases. The length of the drive shaft and the support cylinder and the position of the second bearing are appropriately set according to the position of the draft tube.

  The draft tube communicates with the first conical portion whose diameter decreases from the upper end toward the lower end and the lower end of the first conical portion, for example, as long as it accommodates the axial impeller inside. A first cylindrical portion that is formed in a substantially cylindrical shape that accommodates the axial impeller, a second conical portion that increases in diameter from the upper end communicating with the lower end of the first cylindrical portion toward the lower end, and a lower end of the second conical portion And a second cylindrical portion formed in a substantially cylindrical shape that communicates with the second cylindrical portion.

  According to the stirring apparatus of the present invention, the holding unit attached to the upper part of the processing tank containing the processing liquid, the stirring unit for stirring the processing liquid in the processing tank held by the holding unit, and the processing liquid In a stirring device including a draft tube held by a holding unit so as to be positioned inside, the stirring unit includes a base that is held by the holding unit, a rotation drive unit provided on the base, and a rotation drive Attached to the tip of the drive shaft that protrudes from the support cylinder, the support shaft that is fixed to the base and penetrates the drive shaft inside, An axial-flow impeller located in the draft tube, a first bearing that rotatably holds a drive shaft attached to the base side of the support cylinder, and a drive shaft attached to the distal end side of the support cylinder are rotatably held. You By having the second bearing supported in the horizontal direction by the holding unit in the processing tank, the holding unit can pass through the first bearing and the second bearing even when the rotational speed of the axial impeller is increased. Since the drive shaft is held and the second bearing is supported in the vertical direction and the horizontal direction by the support cylinder and the holding unit, it is possible to suppress the rolling of the rotating axial flow impeller, and the number of rotations is higher than before. Therefore, it is possible to reduce the size of the stirring device and the axial flow impeller.

  When the stirring unit is detachably attached to the holding unit, the stirring unit can be easily maintained.

  In addition, the holding unit is attached to the upper part of the processing tank and has a base having an opening into which the stirring unit is inserted, a support member that supports the draft tube at a tip extending from the base into the processing tank, and a support If the holding unit is provided with a bearing support portion that supports the second bearing fixed to the member in the horizontal direction, the holding unit restricts the movement of the second bearing in the horizontal direction and reliably vibrates the axial impeller. Can be suppressed.

  Further, the second bearing is disposed in an annular member attached to the tip of the support cylinder, and the bearing support portion has an annular frame body into which the annular member is fitted. A projecting member having a conical shape with a diameter decreasing toward the lower part, and having a bearing support portion projecting from the annular frame toward the center of the annular frame and formed with an inclined surface contacting the side surface of the annular member. When the stirrer unit is inserted from the opening of the gantry, the annular member and the protruding member can be firmly fixed by the wedge action.

  Further, if the support member includes an upper support column that is not submerged in the liquid to be processed in which a bearing support unit is provided near the water surface, and a lower support column that is submerged in the liquid to be processed connected to the upper column. The second bearing can be prevented from being immersed in the liquid to be treated and corroded.

  In particular, when the upper support column is formed of a support column formed in a cylindrical shape, the productivity of the holding unit can be improved.

  Furthermore, the draft tube is disposed in the liquid to be treated so that the distance between the upper end of the draft tube and the maximum water level position of the liquid to be treated in the treatment tank increases as the operating speed of the axial impeller increases. If it is a thing, generation | occurrence | production of a vortex can be minimized in the upper end of a draft tube, and efficient stirring can be performed.

  The draft tube has a first conical portion whose diameter decreases from the upper end toward the lower end, and a first cylindrical portion formed in a substantially cylindrical shape that accommodates an axial impeller communicating with the lower end of the first conical portion; When having a second conical portion whose diameter increases from the upper end communicating with the lower end of the first cylindrical portion toward the lower end, and a second cylindrical portion formed in a substantially cylindrical shape communicating with the lower end of the second conical portion, It is not necessary to provide a groove for preventing contact due to vibration of the axial impeller as in the prior art, and fluid loss due to the groove can be prevented.

  Furthermore, when the drive shaft has a first shaft member that extends from the rotary drive unit to the second bearing, and a second shaft member that has an axial impeller at the tip that is detachably connected to the first drive shaft. The first bearing, the second bearing, and the axial flow impeller can be easily repaired and replaced, and the maintainability can be improved.

  FIG. 1 is a schematic view showing a preferred embodiment of the stirring device of the present invention. The stirring device 100 in FIG. 1 is for stirring a liquid to be processed which is arranged on a so-called processing tank TK and accommodated in the processing tank TK, and includes a holding unit 20, a stirring unit 40, and a draft tube 30. Yes. The holding unit 20 holds the stirring unit 40 and the draft tube 30, and when the stirring unit 40 operates, a downward flow in the draft tube 30 is formed, and the liquid to be processed in the processing tank TK circulates.

  FIG. 2 is a schematic diagram illustrating an example of the holding unit 20. The holding unit 20 includes a gantry 21, a support member 22, and the like. The gantry 21 is fixed on the treatment tank TK and has an opening 21a into which the stirring unit 40 is inserted as shown in FIG. A support member 22 for holding the draft tube 30 is fixed to the gantry 21. The support member 22 includes four support columns arranged in a substantially square cross section, and the four support columns are arranged in the processing tank TK so as to have a substantially square cross section.

  The support member 22 includes an upper column 22a and a lower column 22b, and the upper column 22a and the lower column 22b are connected using a flange joint or the like above the water level Wmax of the liquid to be treated. Therefore, the upper column 22a is positioned in the atmosphere of the processing tank TK, and the lower column 22b is positioned in the liquid to be processed. Further, the upper struts 22a are connected to each other by a reinforcing member 22X such as a brace. The reinforcing member 22X increases the rigidity of the entire support member 22 and can improve the vibration damping performance. On the other hand, the lower support 22b is not reinforced by a brace so as not to disturb the suction flow around the upper end of the draft tube 30.

  As will be described later, a bearing support portion 25 for supporting the second bearing 53 is attached to the upper support column 22a (see FIG. 10). Further, a rectifying plate 23 for rectifying the suction flow around the stagnation mouth at the upper end of the draft tube 30 is disposed on the side surface of the lower support column 22b. The rectifying plate 23 extends in the vertical direction (arrow Z direction) and is formed radially toward the diagonal lines of the four columns 22. The rectifying plate 23 also acts as a flow resistor when the draft tube 30 vibrates on a horizontal plane, and can attenuate the vibration of the column member 22.

  FIG. 4 is a schematic view of the draft tube 30 as viewed from above, and FIG. 5 is a schematic view showing the peripheral portion of the draft tube 30. The draft tube 30 will be described with reference to FIGS. The draft tube 30 forms a downward (arrow Z1 direction) flow in the liquid to be treated, and is attached to the lower support 22b. In addition, the holding unit 20 described above is positioned at the center of the processing tank TK so that the draft tube 30 is disposed at the center of the processing tank TK.

  The draft tube 30 has a first conical portion 30a, a first cylindrical portion 30b, a second conical portion 30c, and a second cylindrical portion 30d. Among these, the axial flow impeller 45 is located in the first cylindrical portion 30b. . Then, due to the rotation of the axial flow impeller 45, the liquid to be processed flows into the draft tube 30 from the upper end of the first conical portion 30a and is discharged from the lower end of the cylindrical portion 30b.

  The first conical portion 30a has a substantially conical shape from the upper end toward the lower end, for example, with a gradually expanding angle of about 60 ° and a diameter decreasing. Accordingly, when the liquid to be processed flows into the draft tube 30 from the upper part of the first conical portion 30a, the inlet loss can be reduced and the suction flow can be efficiently guided to the axial flow impeller 45. The first cylindrical portion 30b has a substantially constant diameter, and an axial flow impeller 45 is accommodated therein. The gap between the side wall of the first cylindrical portion 30b and the axial impeller 45 is about 0.0125D on one side (D: impeller diameter), and an annular groove for preventing contact on the draft tube 30 side (see FIGS. 17 and 18). ) Is not provided.

  The second conical portion 30c communicates with the first cylindrical portion 30b and has, for example, a substantially conical shape with a gradually increasing angle of about 10 ° and a diameter increasing from the upper end to the lower end. The second conical portion 30c functions as a diffuser portion, and by reducing a part of the downward flow velocity energy to pressure energy to increase the water flow velocity, the increase in friction loss is alleviated and the flow separation And the expansion loss can be reduced. The second cylindrical portion 30d has a substantially constant diameter, and has an opening for discharging the liquid to be processed in the draft tube 30 toward the bottom of the processing tank TK.

  Here, in the draft tube 30, the distance from the upper end of the first conical portion 30a to the maximum water level position Wmax (referred to as water fog) is, for example, in the range of 1.0D to 1.5D (D: impeller diameter). The positioning is performed by the holding unit 20. In addition, it is not restricted to the range of the said 1.0D-1.5D, You may make it enlarge distance as driving | running rotation speed is high. Thereby, the generation of vortices generated in the suction portion of the draft tube 30 can be reduced, and this distance can reduce the generation of vortices in the suction portion of the draft tube 30, an increase in power, and the suction of surface water. It is appropriately set in consideration of the rotational speed and the like. The draft tube 30 is arranged such that the distance between the bottom of the processing tank TK and the lower end of the cylindrical portion 30c is about 5D to 7D (D: impeller diameter).

  Further, the draft tube 30 has an insertion hole 31 into which the tip of the drive shaft 44 is inserted and a plurality of guide vanes 32 in the first cylindrical portion 30b. The insertion hole 31 has a bullet-like tip and has a diameter that is substantially the same as the boss diameter of the axial flow impeller 45. Then, the boss of the axial flow impeller 45 is inserted into the insertion hole 31.

  The plurality of guide vanes 32 are attached in the draft tube 30 at intervals of about 90 ° in the circumferential direction. The guide vane 32 has a length in the flow direction (arrow Z direction) of about 0.4D (D: diameter of the axial flow impeller 45), and a range of about 40% of the upstream length is the axial flow impeller 45. It is inclined in an arc shape in the direction opposite to the inclination of. The arc has a radius of, for example, about 0.25D (D: the diameter of the axial flow impeller 45), and the radius of the arc is formed to be substantially constant with respect to the radial direction of the draft tube 30. For example, the draft tube 30 and the agitation unit 40 are positioned so that the clearance between the axial flow impeller 45 and the guide vane 32 is about 0.04D (D: impeller diameter). The smaller these gaps are, the smaller the fluid loss can be reduced. Therefore, it is preferable to make them as small as possible in production and practically.

  FIG. 5 is a schematic diagram showing an example of the stirring unit 40. The stirring unit 40 will be described with reference to FIG. The stirring unit 40 includes a base 41, a rotation drive unit 42, a drive shaft 44, and an axial impeller 45. The base 41 has a substantially rectangular flat surface larger than the opening 21 a of the gantry 21, and the stirring unit 40 is held by the holding unit 20 by the base 41 as shown in FIG. 7. The rotation drive unit 42 includes a motor 42a and a speed reducer 42b fixed to the base 41, and the start / stop of rotation and the number of rotations are controlled in the motor 42a and the speed reducer 42b. The drive shaft 44 extends from the rotation drive unit 42 into the processing tank TK and rotates by driving the rotation drive unit 42.

  The axial flow impeller 45 is attached to the tip of the drive shaft 44 and is disposed in the draft tube 30. The axial flow impeller 45 forms a downward flow (in the direction of the arrow Z1) with respect to the liquid to be processed in the draft tube 30 by rotating integrally with the drive shaft 44. The axial flow impeller 45 has a plurality of blades, and the blades are formed with a pitch ratio of 1.4 or 1.2, for example. Here, the pitch means the distance traveled when the spiral surface extended by the axial flow impeller 45 with the geometric blade angle makes one rotation 360 °, and the pitch ratio is obtained by dividing the pitch by the diameter D of the impeller. Means. As this axial flow impeller 45, for example, the impeller disclosed in Japanese Patent Nos. 3239170, 3239171, and 3239172 and other known axial flow impellers can be used.

  Furthermore, the stirring unit 40 includes a support cylinder 50, a first bearing 51, and a second bearing 52. One end side of the support cylinder 50 is fixed to the base 41, and the drive shaft 44 penetrates inside and protrudes from the tip of the support cylinder 50 as shown in FIG. 8. The first bearing 51 rotatably holds the rotation drive unit 42 side of the drive shaft 44 and is accommodated inside the support cylinder 50 and on the base 41 side. The second bearing 52 is attached to the tip of the support cylinder 50 and holds the middle of the drive shaft 44 rotatably.

  The second bearing 52 is supported in the horizontal direction by the holding unit 20 in the processing tank TK. Specifically, as shown in FIG. 9, the second bearing 52 is accommodated in an annular member 53 that is fixed to the outer end of the support tube 50. The annular member 53 has a conical shape whose diameter decreases downward, and an inclined surface is formed on a side surface (see FIG. 6).

  On the other hand, the bearing holder 25 shown in FIG. 10 supports the second bearing 53 in the horizontal direction (arrow XY direction), and is attached below the upper column 22a. The bearing holder 25 includes an annular frame 25a and a protruding member 25b. The annular frame 25a is formed with a diameter slightly larger than the diameter of the axial flow impeller 45 so that the axial flow impeller 45 passes through the inside thereof, and is supported by a member 22Y protruding from each column of the upper column 22a. ing. Three to four protruding members 25b are attached to the inner surface of the annular frame 25a toward the center of the ring. As the projecting member 25b goes vertically downward (in the direction of the arrow Z1), an inclination is formed to contact the side surface of the annular member 53 so that the overhang length becomes longer.

  Here, FIG. 11A shows a top view and a cross-sectional view showing a state in which the second bearing is supported by the bearing holder. When the stirring unit 40 is inserted into the holding unit 20, the annular member 53 is fitted and fixed to the annular frame 25a. At this time, a wedge action acts on the side surface of the annular member 53 and the inclination of the protruding member 25 b, and the second bearing 52 is firmly fixed to the bearing holding portion 25.

  Here, since the bearing holding portion 25 described above is attached to the upper column 22a side that is not submerged, the second bearing 52 is also not submerged. Therefore, the second bearing 52 can be easily lubricated and a commercially available rolling standard bearing can be adopted, and continuous operation can be performed without using a complicated mechanism. That is, it is conceivable to suppress vibrations by adopting a structure in which a bearing is provided in the liquid to be processed near the axial impeller 45 and the drive shaft is supported at both ends. However, when the bearing is immersed in the liquid to be treated, a bearing lubrication device is required, the structure becomes complicated, and the manufacturing cost increases. Furthermore, there is a drawback that the stirring unit 40 cannot be detached from the holding unit 20 and cannot be easily lifted to the land, resulting in inconvenient maintenance. On the other hand, in the stirring device 100 described above, since the second bearing 52 is attached to the upper support column 22a side that is not submerged, continuous operation is possible without using a complicated mechanism.

  In addition, since it is more effective to suppress vibration when the second bearing 52 is installed as low as possible, the second bearing 52 is arranged so as not to get wet with the liquid to be treated and to be located near the maximum water level position Wmax. The height of the bearing support portion 25 and the height of the bearing holding portion 25 are adjusted and installed so as to be about 10 cm higher.

  FIG. 12 is a schematic view showing a state where the stirring unit 40 is installed in the holding unit 20, and a method for installing the stirring unit 40 will be described with reference to FIG. First, the agitating unit 40 is inserted into the opening 21a of the gantry 21 from vertically above with the axial flow impeller 45 facing downward. Thereafter, the agitating unit 40 moves vertically downward (in the direction of the arrow Z1), and the seat surface around the opening 21a of the gantry 21 and the bottom surface of the gantry 21 of the agitating unit 40 come into contact as shown in FIG. (See FIG. 7). At the same time, the annular member 53 on the stirring unit 40 side is fitted into the annular frame 25a on the holding unit 20 side (see FIG. 11). And the base 21 and the base 21 are fixed using fixing members, such as a volt | bolt.

  As described above, since the drive shaft 44 and the first bearing 51 hold the second bearing 53 in the horizontal direction by the holding unit 20, the rolling of the axial flow impeller 45 is effectively suppressed, compared to the conventional case. Operation at a high rotational speed can be performed. Furthermore, the water supply flow velocity can be increased by increasing the operation rotational speed, and even in this case, the same stirring ability as that of the prior art can be obtained by using a smaller axial flow impeller.

  That is, as in the conventional example shown in FIGS. 17 and 18, instead of suppressing the rolling of the axial flow impeller 6, the draft tube is provided with a groove 32, thereby making contact between the axial flow impeller 6 and the draft tube. In the case of prevention, there is a problem that fluid loss in the groove 32 increases, and efficient stirring cannot be performed, and the rotation speed cannot be increased in order to prevent the roll from increasing.

  Furthermore, when the groove | channel 32 is provided in the draft tube 10, the fluid loss in the groove | channel 32 becomes large in proportion to the square of the water supply flow velocity. For this reason, when the apparatus is downsized to increase the water supply flow velocity, it is necessary to reduce the axial width and the impeller radial depth of the groove 32 in order to reduce fluid loss. However, there is a problem that the manufacturing with the conventional welded structure becomes difficult because the processed part becomes small.

  Further, in a treatment tank using this type of stirring device, the distance from the upper part where the drive is installed to the liquid level where the impeller is arranged may reach 1.7 m. At that time, the length of the drive shaft 44 is 2 m or more, which is very long. Even when the device is downsized, the required length of the drive shaft 44 is substantially the same. However, when an appropriate drive shaft diameter is selected in consideration of fluid loss, the size of the conventional shaft is reduced with the downsizing of the axial impeller 45. The drive shaft is thinner than the drive shaft diameter. Therefore, there is a problem that the rigidity of the drive shaft is lowered and vibration is likely to occur.

  On the other hand, since the drive shaft 44 and the first bearing 51 hold the second bearing 53 in the horizontal direction by the holding unit 20, the roll of the axial impeller 45 is effectively suppressed and the rotation is higher than that of the prior art. You can drive in numbers. Furthermore, since the entire stirring apparatus 100 can be reduced in size, the size of the opening provided in the processing tank TK for installing the stirring apparatus 100 can be reduced, and the weight of the apparatus can be reduced, so that the weight of the apparatus can be reduced. The load burden can also be reduced.

  FIG. 14 is a schematic view showing a second embodiment of the stirring device of the present invention, and the stirring unit 240 will be described with reference to FIG. In addition, in the stirring unit 240 of FIG. 14, the part which has the same structure as the stirring unit 40 of FIG. 6 is attached | subjected, and the description is abbreviate | omitted. 14 is different from the stirring unit 40 in FIG. 6 in the structure of the drive shaft.

  In FIG. 14, the drive shaft 244 includes a first shaft member 244 a and a second shaft member 244 b, and the first shaft member 244 a and the second shaft member 244 b are slightly below the second bearing 53 and have a flange 241. Connected by. Thereby, the total length of the stirring unit 40 can be shortened by removing the second shaft member 244b from the first shaft member 244a during maintenance and inspection. That is, when the distance from the upper surface of the processing tank TK to the processing liquid surface is large, the drive shaft 44 becomes very long, and the total length of the stirring unit 40 may exceed 3 m. When the processing tank TK is indoors at a general ceiling height, there is a possibility that the agitating unit 40 cannot be pulled up in the vertical direction (arrow Z direction) with a crane or the like during maintenance and inspection. At this time, as shown in FIG. 14, if the second shaft member 244b has a configuration that can be attached to and detached from the first shaft member 244a, the maintenance of the stirring unit 40 can be performed by pulling up to the height of the first shaft member 244a. Therefore, maintenance and inspection can be performed efficiently even with a special treatment tank TK.

  FIGS. 15 and 16 are schematic views showing a second embodiment of the stirring device of the present invention. The stirring device 300 will be described with reference to FIGS. 15 and 16. 15 and FIG. 16, parts having the same configuration as that of the stirring apparatus 100 of FIG. 1 are denoted by the same reference numerals and description thereof is omitted. The stirrer 200 in FIGS. 15 and 16 differs from the stirrer 100 in FIG. 1 in the shape and structure of the upper support column.

  The upper support column 322 a shown in FIGS. 15 and 16 is formed of a cylindrical support column and is flange-bonded to the gantry 21. The upper support column 322a includes a straight pipe portion 322X having a diameter slightly larger than the diameter of the axial flow impeller 45, and a conical portion 322Y that is positioned below and gradually increases in diameter downward. A flange for fixing the lower support 22b is provided at the lower end of the conical portion 322Y. Reinforcing ribs 322Z are attached to the outer surface of the conical portion 322Y at several locations, and bearing holding portions 25 are provided on the inner surface.

  Thus, by making the upper support column 322a cylindrical, the number of parts of the holding unit 20 can be reduced and assembly can be facilitated, and the manufacturability can be improved.

  Examples of the minimum power that satisfies the required performance of the stirring treatment confirmed in the water tank test in fresh water are shown as Example 1 and Example 2. The required performance in the stirring treatment means that the time average flow velocity at the bottom of the treatment tank is maintained at 0.1 m / s or more so that the sludge does not settle or decay. In addition, in the following Examples 1 and 2, the data of the conventional impeller diameter φ800 mm are also shown for comparison. The stirring power input density is one of the indexes representing the stirring characteristics, and is obtained by dividing the required power by the stirring volume.

<Example 1>
A 7 m × 7 m × 6 m test water tank (treatment tank TK) is used to fill fresh water (liquid to be treated) up to 5.9 m (stir volume: 289 m ³ ), and the axial impeller diameter D and rotation speed of the stirrer 100 in FIG. The stirring results (stirring power input density) when the water supply flow rate is set as shown in Table 1 below are shown. In Table 1 below, an axial flow impeller having a pitch ratio of 1.4 in the first embodiment and a pitch ratio of 0.9 in the conventional type is used, and the pitch ratio is made larger than that of the conventional one and at the same rotational speed. The generated differential pressure lift is large, so that the highest efficiency can be obtained at a larger water supply. Moreover, the bottom average flow velocity shows a value at a position away from the center of the tank (center of the stirring device) 10 cm above the bottom of the tank at a distance in parentheses.

  In Table 1, in Example 1, the axial impeller diameter is reduced by half compared to the conventional type, while the rotational speed is increased approximately three times, and the stirring power input density is made substantially the same value. In other words, even when the device is downsized and the number of revolutions is increased, vibration of the drive shaft and axial impeller is suppressed compared to the conventional example, and it is no longer necessary to form an annular groove in the draft tube. Means reduced.

<Example 2>
An 8 m × 8 m × 10 m test water tank (treatment tank TK) is filled with fresh water (liquid to be treated) up to 10 m (stir volume: 640 m ³ ), and the axial impeller diameter D, rotation speed, and water supply flow rate of the stirrer 100 in FIG. Shows the stirring results (stirring power input density) when is set as shown in Table 2 below. In Table 2 below, the pitch ratio is 1.4 in Example 2, while the conventional type uses an axial impeller with a pitch ratio of 0.9, and the generated differential pressure head at the same rotational speed is large and larger. The highest efficiency was achieved for the amount of water delivered. The bottom average flow velocity indicates a value at a position away from the center of the tank (center of the stirring device) 10 cm above the bottom of the tank at a distance in parentheses.

  In Table 2, in Example 2, the axial flow impeller diameter was reduced to half that of the conventional type, and the stirring power input density was substantially the same even when the rotational speed was increased approximately three times. Value. This is because even if the axial flow impeller is downsized and the rotational speed is increased, the vibration of the drive shaft and the axial flow impeller is suppressed, and the annular groove is no longer required in the draft tube, thereby reducing the flow loss of the liquid to be treated. Means that

  According to each of the above embodiments, the holding unit 20 attached to the upper part of the processing tank TK containing the liquid to be processed, and the stirring unit 40 for stirring the liquid to be processed in the processing tank TK held by the holding unit 20. And a stirrer 100 provided with a draft tube 30 held by the holding unit 20 so as to be located in the liquid to be treated. The rotation drive unit 42 provided on the upper side, the drive shaft 44 that rotates by driving the rotation drive unit 42 extending from the rotation drive unit 42 into the processing tank TK, and the drive shaft 44 that is fixed to the base 41 and penetrates inside. A support cylinder 50, an axial impeller 45 positioned in the draft tube 30 attached to the tip of the drive shaft 44 protruding from the support cylinder 50, and a base 41 side of the support cylinder 50. The first bearing 51 that rotatably holds the attached drive shaft 44 and the drive shaft 44 that is rotatably attached to the distal end side of the support cylinder 50 are horizontally held by the holding unit 20 in the processing tank TK. The holding unit 20 holds the drive shaft via the first bearing 51 and the second bearing 52 even when the rotational speed of the axial flow impeller 45 is increased by having the second bearing 52 supported. Further, since the second bearing 52 is supported in the vertical direction and the horizontal direction by the support cylinder 50 and the holding unit 20, the rolling of the rotating axial flow impeller can be suppressed, and at a higher rotational speed than before. Since the operation becomes possible, the stirrer and the axial flow impeller can be downsized.

  In addition, as shown in FIG. 12, when the stirring unit 40 is detachably attached to the holding unit 20, the maintenance of the stirring unit 40 can be easily performed.

  Moreover, as shown in FIG. 2, the holding unit 20 is attached to the upper part of the processing tank TK and has a base 12 having an opening 21a into which the stirring unit 40 is inserted, and from the base 21 into the processing tank TK. If the holding unit 20 includes a support member 22 that supports the draft tube 30 at the extended tip and a bearing support portion 25 that supports the second bearing 52 fixed to the support member 22 in the horizontal direction, the holding unit 20 is provided. The movement of the second bearing 52 in the horizontal direction can be restricted, and the vibration of the axial impeller 45 can be reliably suppressed.

  Further, as shown in FIG. 11, the second bearing 52 is disposed in an annular member 53 attached to the tip of the support cylinder 50, and the bearing support portion 25 is an annular frame 25 a into which the annular member 53 is fitted. In particular, the annular member 53 has a conical shape whose diameter decreases from the upper part toward the lower part, and the bearing support portion 25 protrudes from the annular frame body 25a toward the center of the annular frame body 25a. When the stirrer unit 40 is inserted from the opening 21a of the gantry 21 when the projecting member 25b is formed with an inclined surface that contacts the side surface of the annular member 53, the annular member 53 and the projecting member 25b It can be firmly fixed by the wedge action.

  In addition, as shown in FIG. 2, the support member 22 is immersed in the liquid to be treated which is not submerged in the liquid to be treated in which the bearing support portion 25 is provided near the water surface, and in the liquid to be treated connected to the upper strut 22a. If the lower support 22b is provided, the second bearing 52 can be prevented from being immersed in the liquid to be treated and corroded.

  In particular, as shown in FIGS. 15 and 16, when the upper column 322 a is a column cylinder formed in a cylindrical shape, the manufacturability of the holding unit 20 can be improved.

  Furthermore, the draft tube is arranged in the liquid to be treated so that the distance between the upper end of the draft tube 30 and the maximum water level position of the liquid to be treated in the treatment tank increases as the operating speed of the axial impeller increases. If it is a thing, generation | occurrence | production of a vortex in the upper end of the draft tube 30 can be minimized, and efficient stirring can be performed.

  As shown in FIG. 4, the draft tube 30 has a first conical portion 30a having a diameter that decreases from the upper end toward the lower end, and a substantially cylindrical housing that accommodates an axial flow impeller 45 that communicates with the lower end of the first conical portion 30a. A first cylindrical portion 30b formed in a shape, a second conical portion 30c having a diameter that increases from the upper end communicating with the lower end of the first cylindrical portion 30b toward the lower end, and an approximately communicated with the lower end of the second conical portion 30c. When having the second cylindrical portion 30d formed in a cylindrical shape, it is not necessary to provide the draft tube 30 with a groove for preventing contact due to vibration of the axial flow impeller as in the prior art, and fluid loss due to the groove can be prevented. it can.

  Further, as shown in FIG. 14, the drive shaft 44 has a first shaft member 244a extending from the rotation drive unit to the second bearing, and an axial flow impeller 45 at the tip detachably connected to the first shaft member 244a. When the second shaft member 244b is provided, the first bearing 51, the second bearing 52, and the axial flow impeller 45 can be easily repaired and replaced, and the maintainability can be improved.

  The embodiment of the present invention is not limited to the above embodiment. For example, the case where four support columns are used as the supporting member of the holding unit 20 in FIG. 1 (see FIG. 1) and the case where a support column is used (see FIG. 15) are illustrated. You may make it arrange | position a support | pillar symmetrically with respect to the arrow Z direction.

  Moreover, in each said embodiment, although the case where the 2nd bearing 52 was attached to the front-end | tip of the support cylinder 50 was illustrated, it has the structure accommodated in the support cylinder 50 near the front-end | tip. Also good. At this time, the holding unit 20 can hold the support cylinder 50 to indirectly hold the second bearing 53 and suppress the roll of the axial impeller 45. At this time, if an inclined surface is formed on the side surface of the support tube 50, a wedge action can be obtained as described above.

  Furthermore, in each said embodiment, although the draft tube 30 has illustrated about the case where it has the 1st cone part 30a, the 1st cylinder part 30b, the 2nd cone part 30c, and the 2nd cylinder part 30d, it is 2nd cone part. Instead of 30c, the first cylindrical portion 30b may be configured to extend to the lower end. Even in this case, it is not necessary to provide a groove in the draft tube 30 as in the prior art (see FIG. 5), and an increase in flow resistance due to the groove 32 can be prevented.

  Further, the draft tube 30 may have a curved shape like a bell mouth instead of the first conical portion 30a. Thereby, the entrance loss when the liquid to be processed flows from the upper part of the draft tube 30 can be further reduced.

  Further, in each of the above embodiments, the case where the drive shaft is rotated and held by the first bearing 51 and the second bearing 53 is illustrated, but the first bearing 51 and the second bearing 53 are supported in the support cylinder 50. You may make it arrange | position a bearing further in between.

The longitudinal cross-sectional view which shows preferable embodiment of the stirring apparatus of this invention The schematic diagram which shows an example of the holding | maintenance unit in the stirring apparatus of FIG. The upper men's example of a stand in the holding unit of FIG. Schematic diagram showing an example of the draft tube of FIG. Schematic showing the periphery of the first conical portion of the draft tube of FIG. The schematic diagram which shows an example of the stirring unit in the stirring apparatus of FIG. The schematic diagram which shows a mode that the base of the stirring unit of FIG. 6 was installed in the mount frame Sectional drawing which shows a mode that the drive shaft was accommodated in the support cylinder of the stirring unit of FIG. Sectional drawing which shows the structure of the 2nd bearing in the stirring unit of FIG. The schematic diagram which shows the structure of the bearing holding part in the holding unit of FIG. Schematic showing how the second bearing is supported by the bearing holder Sectional drawing which shows a mode that a 2nd bearing is supported by a bearing holding part. Schematic diagram showing how the agitation unit is detached from the holding unit Schematic diagram showing how the agitation unit is attached to the holding unit Sectional drawing which shows 2nd Embodiment of the stirring unit in the stirring apparatus of this invention. Sectional drawing which shows 3rd Embodiment of the holding | maintenance unit in the stirring apparatus of this invention. Top view showing an example of the upper column in FIG. A longitudinal sectional view showing an example of a conventional stirring device 15 is a longitudinal sectional view showing an example of an axial flow impeller and a draft tube groove of the stirring device in FIG.

Explanation of symbols

20 Holding unit 21 Base 21a Opening 22 Support member 22a, 322a Upper support 22b Lower support 23 Current plate 25 Bearing support 25a Annular frame 25b Projection member 30 Draft tube 30a First conical part 30b First cylindrical part 30c Second cone Part 30d Second cylindrical part 32 Guide vane 40 Stirring unit 41 Base 42 Rotation drive part 44, 244 Drive shaft 45 Axial flow impeller 50 Support cylinder 53 Annular member 100, 200, 300 Stirrer 244a First shaft member 244b Second shaft Material TK treatment tank

Claims (10)

A holding unit attached to the upper part of the processing tank containing the processing liquid, a stirring unit for stirring the processing liquid in the processing tank held by the holding unit, and a position within the processing liquid In a stirring device provided with a draft tube held by the holding unit
The stirring unit is
A base held by the holding unit;
A rotation driving unit provided on the base;
A drive shaft that rotates by driving the rotation drive unit extending from the rotation drive unit into the processing tank;
A support cylinder fixed to the base and having the drive shaft penetrated therein;
An axial impeller located in the draft tube attached to the tip of the drive shaft protruding from the support cylinder;
A first bearing for rotatably holding the drive shaft attached to the base side of the support cylinder;
And a second bearing supported in the horizontal direction by the holding unit in the processing tank for rotatably holding the drive shaft attached to the front end side of the support cylinder. Stirring device.   The stirring device according to claim 1, wherein the stirring unit is detachably attached to the holding unit.   The holding unit is attached to the upper part of the processing tank and has a gantry having an opening into which the stirring unit is inserted, and a support that supports the draft tube at a tip extending from the gantry into the processing tank. The stirring device according to claim 1, further comprising a member and a bearing support portion that supports the second bearing fixed to the support member in a horizontal direction.   The second bearing is housed in an annular member attached to the tip of the support cylinder, and the bearing support portion has an annular frame for fitting the annular member. The stirring device according to claim 3.   The annular member has a conical shape in which the diameter decreases from the upper part to the lower part, and the bearing support portion contacts the side surface of the annular member protruding from the annular frame toward the center of the annular frame. The stirring device according to claim 4, wherein the stirring device has a protruding member formed with an inclined surface in contact therewith.   The support member includes an upper support column that is not submerged in the liquid to be processed in which the bearing support portion is provided near the water surface, and a lower support column that is submerged in the liquid to be processed connected to the upper support column. The stirring device according to claim 4 or 5, wherein   The stirring device according to claim 6, wherein the upper support column is a support column formed in a cylindrical shape.   The draft tube is disposed in the liquid to be treated so that the distance between the upper end of the draft tube and the maximum water level position of the liquid to be treated in the treatment tank increases as the operating speed of the axial impeller increases. The agitator according to any one of claims 1 to 7, wherein the agitator is disposed in the position.   The draft tube has a first conical portion whose diameter decreases from the upper end toward the lower end, and a first cylindrical portion formed in a substantially cylindrical shape that houses the axial flow impeller communicating with the lower end of the first conical portion; A second conical portion whose diameter increases from the upper end communicating with the lower end of the first cylindrical portion toward the lower end, and a second cylindrical portion formed in a substantially cylindrical shape communicating with the lower end of the second conical portion. The stirrer according to any one of claims 1 to 8, wherein the stirrer is provided.   The drive shaft includes a first shaft member that extends from the rotary drive unit to the second bearing, and a second shaft member that has the axial flow impeller at a tip that is detachably connected to the first shaft member. The stirring device according to any one of claims 1 to 9, wherein

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