JP6650221B2 - Stirrer - Google Patents

Description

  The present invention provides a stirring device, for example, a digestion tank for treating raw sludge, surplus sludge, and garbage by methane fermentation, a stirring tank for stirring a liquid in which a liquid and a slurry are mixed, a flat tank, and the like. The present invention relates to a stirrer applicable to various kinds of stirring such as stirring and gas-liquid stirring.

  For example, stirring in a digestion tank is one of the performances in which it is necessary to keep the inside of the tank uniform and maintain a digestibility (organic matter decomposition rate). In addition, the sludge to be put in contains inorganic solids and the like, and has high sedimentation. As these solids settle and accumulate at the bottom, the effective volume in the digester decreases, which adversely affects digestibility.

  In addition, the generation of sediment at the bottom of the tank hinders inspection work at the time of inspection inside the tank, increasing the time and effort for removing the sediment (dredge) as necessary, or depending on the situation, waste disposal There is a problem that costs increase, such as necessity.

  Therefore, it is required to stir without generating sediment at the bottom of the tank, but increasing the stirring intensity leads to an increase in stirring power.

  FIG. 10 shows a stirrer a applied to a conventional biological treatment which has solved the above-mentioned problems. The stirrer a is a cylindrical stirrer b and a radial stirrer provided at the bottom of the stirrer b. A plurality of stationary blades c, and a rotating blade d, which is provided above the stationary blades c and near the liquid level and extends radially and includes, for example, four blades e. Consists of a straight rectangular band-shaped flat paddle blade having a plane perpendicular to the rotation direction of the rotary blade d.

  The conventional stirring device a can be operated with low shear and low power without damaging the carrier in the tank b, and can stir the inside of the stirring tank b extremely uniformly and easily. 1).

JP-A-7-60093

  The above-mentioned conventional stirring device can be operated with low power, but in recent years, further low power and the same stirring performance as the conventional one are required.

  An object of the present invention is to further improve the above-described conventional stirring device, and to provide a stirring device which can lower the power and stir the inside of the stirring tank very uniformly.

  The stirring device of the present invention includes a stirring tank, a rotating blade provided in the stirring tank, and a radially extending stationary blade provided at the bottom of the stirring tank, wherein the rotating blade has one or more flat taper. It is characterized by consisting of wings.

  Further, the flat taper blade is characterized in that the outer shape is such that the area gradually decreases outward from the rotation axis of the stirring blade.

  In the flat taper blade, the outer shape of the flat taper blade may be such that an upper side extending in a horizontal direction, an outer side extending in a vertical direction, an inner side extending in a vertical direction, and a slant in a straight line outward. It is characterized by comprising a lower side extending upward.

  Further, the apparatus further comprises a rotation control device for controlling the rotation of the rotor.

  Further, the rotation control device is a control device that changes a rotation speed of the rotary wing.

  Further, the rotation control device is a control device that rotates the rotation of the rotary wing in forward and reverse directions.

  Further, the flat taper blade is provided so as to be tiltable with respect to the rotation axis of the rotary blade.

The stirrer according to the present invention includes a stirrer provided with an opening in a ceiling portion, and one or a plurality of flat plates provided to be tiltable in a vertical direction with respect to a rotation axis provided in the stirrer. a tapered wing or Ranaru rotor blades, become more and vanes extending radially provided on the bottom of the agitation tank, wherein the rotor blades, the specific gravity of the rotary blade, the specific gravity of the liquid to be treated which is placed into the agitation tank When the rotating blade is not inserted into the liquid to be treated, the rotating blade hangs down due to gravity, so that the diameter of the rotating blade is smaller than the opening diameter of the opening of the ceiling portion. When it is inserted into the liquid to be treated in a small folded state, it is configured to be tilted upward by buoyancy to open at a desired angle. Further, the stirring device of the present invention includes a stirring tank provided with an opening in a ceiling, and one or more stirring tanks provided to be vertically tiltable with respect to a rotation shaft provided in the stirring tank. a flat tapered wing or Ranaru rotor blades, and more become the vanes extending radially provided on the bottom of the agitation tank, wherein the rotor blades, wherein, when not rotating about the rotational axis downwardly by gravity Hanging down, it becomes a folded state smaller than the opening diameter of the opening of the ceiling portion, and when rotating around the rotation axis, it is tilted upward by centrifugal force and opened at a desired angle. It is characterized by comprising.

  According to the present invention, the inside of the stirring tank can be stirred very uniformly and easily, and the operation can be performed with lower power.

  Further, according to the present invention, since the wing body (flat taper wing) can be made smaller than the conventional wing body, the opening of the stirring tank can be made smaller, or the invention can be applied to a stirring tank having a smaller opening. Or, it becomes easy to put in and out of the opening of the stirring tank, and maintenance becomes easy.

  Further, according to the present invention, as compared with the conventional wing body, the rising flow in the central portion in the tank can be more effectively discharged outward by the wing body (flat tapered wing). The amount can be increased, and the flow velocity at the tank bottom can be increased. Further, according to the present invention, even when a wing body smaller than the conventional wing body is used, the same discharge rate or the same flow velocity at the bottom of the layer as the conventional wing body can be achieved with low power.

  Further, by controlling the rotation of the rotor, the average power can be reduced to below the conventional power.

  In addition, since the rotating blades can be folded, the opening of the stirring tank can be reduced, or the stirring blade can be applied to a stirring tank having a small opening, or the stirring tank can be easily taken in and out of the opening. , Making maintenance easier.

It is a vertical front view of the stirring device of Example 1 of this invention. FIG. 2 is a plan view cut along the line II of FIG. 1. It is an explanatory enlarged front view of a wing. It is a vertical section front view for explanation of the conventional flat paddle wing. It is a longitudinal section front view for explanation of the flat turper wing of the present invention. It is a graph which shows the relationship between Reynolds number and power number. It is a vertical front view of the stirring apparatus of the other Example of Example 1 of this invention. It is an explanatory enlarged front view of the rotor of Example 2 of this invention. It is an explanatory enlarged front view of the rotor of Example 2 of this invention. It is a vertical front view of the conventional stirring device.

  An embodiment of the mode for carrying out the present invention will be described below.

  First Embodiment A first embodiment of the present invention will be described with reference to FIGS.

  Reference numeral 1 denotes a stirrer of Example 1 of the present invention, 2 denotes a stirrer of the stirrer 1, and the stirrer 2 is, for example, a vertical cylinder, an elliptical cylinder, or a rectangle having a diameter of 20 m. An opening 3 and a lid 4 of the opening 3 are provided in the center of the ceiling 2 a of the stirring tank 2.

  Reference numeral 5 denotes a rotating blade, which is, for example, four blades 6 fixed radially outward to a lower end of a rotating shaft 5a via a boss 5b, and is composed of four blades 6; 5 a is suspended coaxially with the center axis of the stirring tank 2 and penetrates the lid 4, and the rotating blade 5 is inserted into the stirring tank 2.

  The wing plate 6 is formed of a trapezoidal plate-shaped flat taper wing having a surface perpendicular to the rotation direction of the rotation shaft 5a, and the outer shape of the wing plate 6 extends outward from the rotation shaft 5a. For example, the shape gradually decreases in area toward the outside. For example, an upper side 6a extending in the horizontal direction, an outer side 6b extending in the vertical direction, an inner side 6c extending in the vertical direction, and an oblique line extending outward are linearly inclined. The lower side 6d extends upward.

  The rotating blade 5 is configured to rotate in the vicinity of the liquid surface of the liquid to be treated in the stirring tank 2 via the rotating shaft 5 a by the driving of a motor 7 provided above the stirring tank 2. .

  Reference numeral 8 denotes a stationary blade, and the stationary blade 8 is formed of, for example, a linear band-shaped plate, and the band-shaped plate is radially fixed, for example, four at the center of the bottom 2b in the stirring tank 2. In addition, a gap is formed at the center of the bottom corresponding to the intersection of these strips.

  Next, the operation and effect of the stirring device of the present invention will be described.

  For example, in the stirring tank 2 used as a digestion tank containing a wastewater containing raw sludge, surplus sludge, garbage, and the like and a liquid to be treated containing microorganisms that process the wastewater and perform methane fermentation, When the nozzle 5 is rotated, the liquid to be treated generates a downward swirling flow along the inner peripheral surface of the stirring tank 2 as shown in FIG. 1 and rises at the center by the stationary blades 8 of the bottom 2b. A stream is generated, and the liquid to be treated circulates in the stirring tank.

  By the way, the blade plate 6 including the flat tapered blade of the present application can lower the power number (Np) of the blade body as compared with the conventional flat paddle blade e.

Here, in general, the motor output (P) for rotating the rotor can be expressed by the number of powers (Np) × the number of rotations (N) ³ × the blade diameter (d) ^5. In this case, the number of revolutions (N) can be increased by decreasing the number of powers (Np).

  In addition, in order to stir the inside of the stirring tank so that sediment does not accumulate on the bottom of the stirring tank, the flow velocity at the bottom of the stirring tank is important. When the tip speed (VTip = N × d × π) is constant, the blade diameter (d) can be reduced by increasing the rotation speed (N).

  From the above, the motor output (P) is proportional to the cube of the rotation speed (N) and proportional to the fifth power of the blade diameter (d), so that the blade tips of the conventional flat paddle blade and the flat taper blade of the present application are obtained. When the speed (VRip) is the same, the effect of lowering the power (P) by reducing the blade diameter (d) is greater than the effect of increasing the power (P) by increasing the rotation speed (N). .

  Therefore, instead of using the conventional flat paddle blade e, by using the blade 6 made of the flat tapered blade of the present invention, the blade 6 having a smaller blade diameter than the blade diameter of the conventional flat tapered blade is used. Therefore, the motor output (power) can be effectively reduced while maintaining the stirring effect of the conventional flat paddle blade e.

  Further, in the agitating device of the present invention, the updraft is generated at the center of the bottom of the tank by using the stationary blades 8, so that the base portion of the blade plate 6 composed of the flat taper blades has a large area. In response to the upward flow, the liquid to be stirred can be more effectively discharged in the radial direction.

  Therefore, compared to the case where stirring is performed using only the flat taper blade without using the stationary blade 8, the case where the stirring is performed using both the stationary blade 8 and the flat taper blade in the radial direction under the same condition is performed. The discharge amount can be increased, and the flow velocity at the bottom of the layer can be increased. Therefore, when comparing the case where only the flat taper blade is used and the case where both the stationary blade 8 and the flat taper blade are used under the condition that the flow velocity at the bottom of the layer is the same, the flat taper blade is better. Since the blade diameter can be reduced, the power can be more effectively reduced by the effect of reducing the blade diameter.

  According to the present invention, it is possible to use a blade body having a small blade diameter while maintaining the same stirring performance as that of a conventional flat paddle blade stirring device. Become.

  Hereinafter, an example of the conventional flat paddle blade and an example of the flat taper blade of the present invention will be described with reference to FIGS.

  In the digestion tank or the like applied in the present invention, in order to stir the inside of the stirring tank so that sediment does not accumulate on the bottom of the stirring tank, the flow velocity at the bottom of the stirring tank is important, and the flow velocity is low power, In addition, a flow rate at which no deposit is deposited on the bottom of the stirring tank is the optimum flow rate. The flow velocity is approximately proportional to the area of the blade.

  Therefore, in order to investigate the shape of the flat paddle blade with the smallest power number in the area of the blade at which the optimum flow velocity is obtained, the shape of the flat paddle blade is changed so that the area of the flat paddle blade is constant. The relationship between power characteristics and flow action was obtained by experiment and numerical simulation.

  As a result, an example of an optimal conventional flat paddle blade is shown in FIG.

  The flat paddle blade has a flat paddle with a diameter D of the stirring tank of 12 m, a distance h from the water surface to the flat paddle blade of 1.5 m, a blade diameter of the stationary blade of 3.4 m, and a blade width of 0.8 m. The blade diameter d of the blade is 4.2 m, and the blade width b is 1.1 m. The peripheral speed of the tip of the blade required to obtain a flow velocity of 10 cm / s or more as a reference for fluidizing the bottom of the tank was Vyip ≧ 1.05 m / s.

  Next, an example of the flat taper blade of the present invention is shown in FIG.

When the diameter D of the stirring tank is 12 m, the distance h from the water surface to the flat paddle blade is 1.1 m, the blade diameter of the stationary blade is 3.4 m, and the blade width is 0.8 m, the flat taper blade has a blade diameter. Is 4.0 m, the blade width b ₂ (inner side 6 c) is 1.4 m, and the blade width b ₁ (outer side 6 b) is 0.6 m. The peripheral speed of the tip of the blade required to obtain a flow velocity of 10 cm / s or more as a reference for fluidization of the tank bottom was Vyip ≧ 1.10 m / s.

  FIG. 6 shows the results obtained by experiments on the power number (Np) of the conventional flat paddle blade and the power number of the flat taper blade of the present invention in Reynolds number (Re) in a flat digester. Show.

  From this experimental result, it is found that the power number (Np) of the blade diameter (4.0 m) of the flat taper blade of the present invention is lower than the blade diameter (4.2 m) of the conventional flat paddle blade.

As described above, the flat taper blade of the present invention has the same flow velocity as the reference for fluidization of the tank bottom, despite the smaller blade diameter, blade area, and blade weight compared to the conventional flat paddle blade. In this case, as described above, the power of the flat tapered blade can be reduced as compared with the flat paddle blade, and the blade diameter can be reduced although the tip peripheral speed is increased. × motor speed (N) ³ × blade diameter (d) The motor output (P) represented by ⁵ can be reduced.
Thus, it can be said that the flat taper blade is superior in both the initial cost of the product and the running cost of power consumption.

  In addition, when the lateral diameter of the conventional flat paddle blade e is, for example, 9 m, even if the lateral diameter of the blade body 6 of the flat tapered blade of the present invention is 6 m, substantially the same stirring performance can be exhibited.

  Further, in the present invention, the blade diameter of the blade plate 6 can be reduced, so that the diameter of the opening 3 of the stirring tank 2 can be designed to be smaller than that in the related art. Further, the stirring tank 2 having a small opening 3 can be used. Further, it is easy to take out the rotary blade 5 from the opening 3 of the stirring tank 2.

  As shown in FIG. 7, a rotation control device 9 having an inverter device, a variable transmission, and the like is separately provided in the motor 7, and the rotation speed of the rotor 5 is periodically changed by the rotation control device 9. Or, the rotation of the rotary wing can be rotated forward and reverse.

  Specifically, using the rotation control device 9, normally, a first desired amount of deposit such as slurry is generated on the bottom 2 b in the tank within a range that does not affect the digestibility. The rotating blade 5 is rotated at a stirring rotation speed for a first desired time. After the elapse of the first desired time, the rotary blade 5 is rotated at a second agitation speed increased from the first agitation speed for a second desired time, so that The accumulated sediment is raised and the inside of the tank is made uniform.

  Then, if necessary, after the second desired time has elapsed, the stirring blade 5 is rotated at the first stirring speed in the normal state for the first desired time, and After the elapse of the first desired time, the rotor 5 is rotated at the second desired agitation speed for the second desired time, and the sediment accumulated in the tank bottom 2b is raised, The inside of the tank is made uniform, and this is repeated as necessary.

  Then, the operation time at the first desired time in the normal time is lengthened, and the low-speed operation at the long time and the speed-up operation at the second desired time are shortened and the operation time at the second desired time is short. By doing so, the average power can be reduced to below the conventional power.

  In addition, depending on the equipment operation method, in the case of equipment that performs the operation of intermittently extracting the liquid to be treated in the tank, speed-up operation is performed before extracting the liquid to be treated in the tank, and during other periods, Alternatively, the vehicle may be driven at a low speed.

  The rotation control device 9 may periodically rotate the stirring blade 5 in the reverse direction.

  By such control, a flow in the opposite direction is generated, and it becomes possible to remove a fiber component in the input sludge called scum, which is entangled with the piping, the rotating blades and the like in the tank.

In the second embodiment of the present invention, as shown in FIGS. 8 and 9, the base of each blade plate 6 of the rotary wing 5 in the first embodiment is provided on a boss 5 b of the rotary shaft 5 a. in the vertical direction via the 10 (in Ri shaft circumference in the radial direction) as well as tiltably connected, the material of each vane 6, it is assumed in the specific gravity less than the specific gravity of the liquid to be treated.

  Further, there is provided a tilt preventing portion 11 for preventing the blade 6 from tilting more than a desired tilt angle.

  In the second embodiment of the present invention, when the rotor 5 is not inserted into the liquid to be treated, the rotor 5 is moved downward by gravity, as shown in FIG. And fold down.

  Then, when the folded rotary blade 5 is inserted into the liquid to be treated in the stirring tank 2, as shown in FIG. 5, the respective blades 6 move upward due to buoyancy. To tilt.

  When the wings 5 are tilted to a desired inclination angle when rotating the rotary wings 5, for example, when the wings are opened horizontally, the upper end of the wings 6 is moved to the tilt preventing portion 11. , The inclination thereof is prevented, and the respective wing bodies 6 can be opened at a desired inclination angle when the respective wing bodies 6 are used for rotation.

  In addition, in order to prevent the wing body 6 from tilting (rotating) in the opposite direction when it floats, a regulating means (not shown) for regulating the rotation direction of the wing plate 6 as necessary. May be provided.

  By rotating the rotor 5 in the above state, the inside of the stirring tank 2 can be stirred.

  According to the second embodiment of the present invention, even when the blade diameter of the rotary blade 5 at the time of rotating use is larger than the opening diameter of the opening 3 of the stirring tank 2, the rotary blade 5 is folded. Thereby, the rotating blade 5 can be inserted into the tank.

  Further, since the rotary wing 5 is extended to a usable state by utilizing buoyancy using a specific gravity difference, a complicated mechanism is not required.

  Instead of making the specific gravity of the blade 6 smaller than the specific gravity of the liquid to be treated, the centrifugal force causes the blade 6 to open at a desired inclination angle by rotating the rotary blade 5. Is also good.

  In addition, a weight (not shown) may be provided on each of the blades 6 in order to easily open the blades 6 by centrifugal force generated by the rotation of the rotary blades 5.

  In the second embodiment, the present invention can be applied to a conventional flat paddle blade.

REFERENCE SIGNS LIST 1 stirrer 2 stirring tank 2 a ceiling 2 b bottom 3 opening 4 lid 5 rotating blade 5 a rotating shaft 5 b boss 6 wing plate 6 a upper side 6 b outer side 6 c inner side 6 d lower side 7 motor 8 stationary blade 9 rotation control Device 10 Pivot point 11 Tilt prevention unit

Claims (2)

A stirred tank having an opening provided in the ceiling portion, with respect to the rotation shaft provided by hanging into the stirring tank, one or more flat tapered wing or Ranaru rotor blades arranged tiltably in the vertical direction And a radially extending stationary blade provided at the bottom of the stirring tank,
The rotating blade is formed such that the specific gravity of the rotating blade is smaller than the specific gravity of the liquid to be treated contained in the stirring tank,
When the rotor is not inserted into the liquid to be treated, the rotor hangs down due to gravity and is in a folded state smaller than the opening diameter of the opening of the ceiling,
A stirrer characterized in that, when inserted into the liquid to be treated, it is tilted upward by buoyancy to open at a desired angle. A stirred tank having an opening provided in the ceiling portion, with respect to the rotation shaft provided by hanging into the stirring tank, one or more flat tapered wing or Ranaru rotor blades arranged tiltably in the vertical direction And a radially extending stationary blade provided at the bottom of the stirring tank,
When the rotor is not rotating around the rotation axis, the rotor hangs down due to gravity to be in a folded state smaller than the opening diameter of the opening of the ceiling,
The agitating device is configured to be tilted upward by centrifugal force and open at a desired angle when rotating around the rotation axis.

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