JP4093272B2 - Microbubble and micromist generator - Google Patents

Description

  The present invention relates to a microbubble and a micromist generator that efficiently and in large quantities generate small-diameter microbubbles and micromist.

  Fine bubbles having a particle size of about 60 μm or less are called microbubbles, and it has been elucidated that microbubbles having a particle size of 10 tens μm or less have a bioactive effect. Microbubbles of 10 tens μm or less are easily dissolved and dispersed in a liquid and exhibit a bioactive action on living organisms. The smaller the particle size of the microbubbles, the better the bioactive action. Since microbubbles are just bubbles, they are naturally friendly and are expected to be used in many fields including water purification and aquaculture, and various microbubble generators have been developed.

  In the microbubble generator of Patent Document 1, a plate is installed in a pipe, the flow velocity of flowing water is changed to create a negative pressure in the pipe, gas is self-primed from the gas supply pipe into the pipe, and gas is mixed By colliding the liquid with the plate in the pipe, the gas mass is pulverized using a shearing action, and microbubbles are generated from the opening formed in the pipe and / or the flow path behind the plate.

In Patent Document 2, the flow direction is switched at the same time by synchronizing the ejection direction of a plurality of fluids at regular intervals without using any direction switching device using a plurality of intersecting flow paths, thereby generating a cross flow. An apparatus is disclosed (hereinafter, such a cross flow of fluid is called a flip-flop flow).
JP 2005-334869 A Japanese Patent No. 2841173

  FIG. 10 is a particle size distribution diagram of microbubbles generated by the microbubble generator described in Patent Document 1. As is apparent from FIG. 10, the microbubble generating device of Patent Document 1 generates many bubbles having a peak value of 40 to 60 μm, and hardly generates microbubbles of 10 or less μm that are useful for physiological activity. There is a problem.

  In addition, in order to suck and shear gas, a pump capable of generating a strong water pressure is necessary, and there is a problem that the apparatus becomes complicated.

  Furthermore, since microbubbles are generated only in a certain direction, there is a problem that the diffusion effect is small.

  The device of Patent Document 2 is a self-excited vibration device in a fluid ejection direction, and only describes that the flow is switched at regular intervals by self-excited vibration, and does not describe any generation of microbubbles.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to use a flip-flop flow and use a micro-bubble of 10 tens μm or less without using another device such as a gas-liquid dissolving device or a pump. An object of the present invention is to provide an apparatus capable of generating a large amount of bubbles and diffusing microbubbles over a wide range.

The present invention is a network flow path that generates a flip-flop flow by joining and shunting a group of parallel flow paths and another group of parallel flow paths on the same plane via a number of shunt walls. A plurality of gas suction holes are arranged side by side on the side where the adjacent flow dividing wall is closest and a side surface of the flow dividing wall body, and a plurality of the gas suction holes are made to be close to a place having a high negative pressure effect. A gas is sucked from the gas suction hole to increase the amount of microbubbles generated .

  The diameter of the gas suction hole is 0.1 mm to 1 mm.

Furthermore, the present invention is a network flow path that generates a flip-flop flow by joining and diverting a group of parallel flow paths and another group of parallel flow paths on the same plane via a number of flow dividing walls. A plurality of liquid suction holes arranged side by side on the side surface of the flow dividing wall body closest to each other, and a plurality of the liquid suction holes are placed close to a portion having a high negative pressure effect. The liquid is sucked from the liquid suction hole to increase the amount of generated droplets.

  According to the microbubble generator of the present invention, a large amount of microbubbles having a particle size of 13 μm or less can be generated. The reason for this is that the gas is naturally aspirated by the ram effect generated in the flow path, so that the gas does not enter the flow path suddenly but is sucked out gradually. Moreover, it is because it shears so that it may be caught in the edge part of a gas suction hole. Furthermore, the sucked gas is sheared to be small and constant by the liquid in which the flow velocity in the vicinity of each gas suction hole is almost constant.

  In addition, because the ram effect generated by the flip-flop flow naturally inhales gas to generate microbubbles, a pump, a gas-liquid dissolving device, and the like are not necessary, and a simple device can be realized.

  Furthermore, for the reasons described above, there is an advantage that energy efficiency is high because electric power for directly generating microbubbles is not required.

  Furthermore, since a plurality of gas suction holes can be provided in each branch wall and a large amount of gas can be sucked, a large amount of microbubbles can be generated.

  Furthermore, according to the microbubble generator of the present invention, since the microbubble discharge direction is automatically switched periodically by the flip-flop flow, there is an advantage that the microbubbles can be diffused over a wide range without using a separate diffusion device. .

  According to the micromist generator of the present invention, it is possible to generate and diffuse a large amount of micromist having a small particle diameter. This is because the liquid is naturally aspirated by the ram effect generated in the flow path, so that the liquid does not suddenly enter the flow path but is sucked out in a gradually drawn manner. Moreover, it is because it is sheared so that it may catch on the edge part of a liquid suction hole. Furthermore, the sucked liquid is sheared to be small and constant by the gas flowing at a substantially constant flow velocity near each liquid suction hole.

  FIG. 1 is a perspective view schematically showing a microbubble generator according to the present invention. FIG. 2 is a perspective view showing a cross section of the merging / dividing branch channel. FIG. 3 is a top view showing a place where the ram effect is generated in the network flow path. FIG. 4 is a measurement diagram of water head pressure at the cross section of the merge / split branch channel. FIG. 5 is a flow velocity distribution diagram showing the average flow velocity of the liquid behind the branch wall bodies in the third and fifth rows from the upstream. FIG. 6 is a perspective view of a flow dividing wall body provided with a plurality of gas suction holes. FIG. 7 is a photograph showing switching of the discharge direction of microbubbles in the discharge unit. FIG. 8 is a top view showing a flip-flop flow when the network channel crossing angle is 30 degrees. FIG. 9 is a particle size distribution diagram of microbubbles generated by this apparatus.

  An outline of a microbubble generator according to the present invention will be described with reference to FIG.

  The microbubble generator of the present invention includes a large number of flow dividing wall bodies 12 and a network flow path 11 in which a group of parallel flow paths and another group of parallel flow paths intersect on the same plane via the large number of flow dividing wall bodies 12. And an inflow portion 13 and a discharge portion 14.

  Twenty-seven shunt wall bodies 12 are arranged in a staggered manner, and six rows are provided from the inflow portion 13 to the discharge portion 14. Each of the flow dividing wall bodies 12 is provided with a gas suction hole 21 in the closest portion between the adjacent flow dividing wall bodies 12 facing each other. Each branch wall 12 has one gas suction hole 21 on each side surface, and 54 gas suction holes 21 as a whole are provided. The rear part of the branch wall 12 in the sixth row from the inflow part 13 is cut out so as not to prevent the liquid and microbubbles from being discharged.

  The liquid that has entered from the inflow portion 13 enters the network flow path 11, and is repeatedly diverted and merged by the diversion wall body 12 and is discharged from the discharge portion 14. When a certain flow velocity is exceeded, a flip-flop flow is generated, gas is sucked and sheared from the gas suction hole 21 into the flow path, and microbubbles are discharged from the discharge portion 14 together with the liquid while the discharge direction is periodically switched. The

  The flip-flop flow will be described. Due to the fluid flow in the network flow path 11, a separation vortex is generated on the rear side surface of the branch wall 12. When a separation vortex is generated on one rear side, a pressure change is generated, and a separation vortex is also generated on the other rear side. Separation vortices are alternately generated on both rear side surfaces of the flow dividing wall body 12, and Karman vortex train vibration is generated in which the separation vortices alternately flow backward. Since the network flow paths 11 intersect, the separation vortices flow while alternately intersecting. When the crossing angle of the network channel 11 is 20 to 60 degrees, it is presumed that the upstream and downstream Karman vortex street vibrations are synchronized and a crossing flow called a flip-flop flow is generated.

  Between the inflow part 13 and the discharge part 14, it is preferable to provide the flow dividing wall bodies 12 in four or more rows. When the shunt wall bodies 12 are in two rows, a flip-flop flow does not appear, and the flow remains in a state where the flow veins are offset in either direction. If there are 3 or more rows, a divergent flip-flop flow may appear, but it is unstable, and if it is 4 or more rows, a flip-flop flow clearly appears.

  Moreover, it is preferable that the front ends of the flow dividing wall bodies 21 in each row are arranged so as to be linearly aligned in parallel with the inflow portion 13 and the discharge portion 14. The expression of the flip-flop flow is stabilized.

  Next, generation of microbubbles according to the present invention will be described with reference to FIGS.

  FIG. 2 is a perspective view showing a merging / dividing branch channel cross section 31 (a merging / diverging branch channel cross section that is the closest point between the adjacent and adjacent diverting wall bodies 12). FIG. 2 is an enlarged view of a pair of opposing flow dividing wall bodies in the apparatus shown in FIG. 1. The gas suction hole 21 is provided at a location in contact with the merging / dividing branch passage cross section 31 of the dividing wall body 12.

  In addition, it is preferable that the confluence / diversion branch passage section 31 is square. When the cross section 31 of the merging / dividing branch channel is square, a flip-flop flow is stably generated, but when the aspect ratio is large like a rectangle, the expression of the flip-flop flow becomes unstable.

  FIG. 3 shows the ram effect appearing portion generated between the pair of opposing flow dividing wall bodies 12 shown in FIG. 2 from above. A ram effect that generates a negative pressure appears in the vicinity of the branch wall of the cross-section 31 of the merge / split branch channel, where the flow velocity is the highest and the pressure is the smallest in the network channel 11. The gas suction hole 21 is close to a place where the ram effect is manifested.

  A pressure change due to the ram effect in the cross section 31 of the merging / dividing branch channel will be described with reference to FIG. The water head pressure in the case where the average flow velocity at the confluence / diversion branch passage section 31 is measured at 2.5 m / s using a network passage in which the confluence / diversion branch passage section 31 is a square having a side of 2 cm is shown. The water head pressure at the central portion of the cross-section 31 of the merged / divided branch flow path is 15 cm, whereas it is −10 cm near the branch wall 12. It can be confirmed that negative pressure is generated at the place where the ram effect is manifested. Since the gas suction hole 21 is provided close to the location where the ram effect appears, the gas is naturally sucked into the network flow path 11.

  As described above, by providing the gas suction hole 21 on the side surface of the branch wall body 12 close to the location where the ram effect is generated in the network flow path 11, the gas outside the flow path is naturally sucked into the flow path. The sucked gas is sheared by the liquid flowing in the flow path 11. In the vicinity of the gas suction hole 21, the maximum flow velocity in the network flow path 11 is generated, so that the sucked gas is instantaneously sheared and microbubbles having a small particle diameter are generated.

  The flow rate in the network channel 11 is slower than that of the conventional microbubble generator. However, the gas is effectively sucked by the ram effect generated in the merge / branch branch flow path. The suction of the gas by the ram effect does not force the gas suction hole 21 from the outside, so that the gas is sucked so as to be gradually drawn out, and the gas is not sucked rapidly. Further, the sucked gas is sheared so as to be caught by the edge portion of the gas suction hole. For this reason, microbubbles smaller than the diameter of the gas suction hole are generated.

  In the flow path, the dissolved gas in the fluid is separated from the fluid along with the separation vortex, and bubbles are generated. Bubbles generated by the separation vortex are larger as the flow rate is higher. In the present invention, since the flow velocity is lower than that of a conventional microbubble generator, bubbles generated with the separation vortex are also reduced.

  FIG. 5 is a flow velocity distribution diagram showing the average flow velocity of the liquid behind the branch wall 12 in the third and fifth rows from the upstream side. FIG. 4A is a flow velocity distribution diagram behind the flow dividing wall bodies in the third row from the upstream, and FIG. 4B is a flow velocity distribution diagram behind the flow dividing wall bodies in the fifth row from the upstream. In the flip-flop flow, the flow velocity becomes maximum in the vicinity of the branch wall body 12 of the merge / split branch channel. Further, the average flow velocity is substantially equal on both sides behind the branch wall 12. Furthermore, the flow velocity distributions behind the branch wall bodies 12 in the third row and the fifth row are substantially equal. For this reason, the gas is sucked from the gas suction holes 21 provided in each row substantially uniformly and is sheared constantly. Therefore, the particle size distribution of the microbubbles generated from each gas suction hole 21 is adjusted.

  Moreover, it is possible to generate more microbubbles by providing one or more gas suction holes 21 in each branch wall 12. Since the gas can be sucked from the plurality of gas suction holes 21, it is possible to increase the proportion of microbubbles in the discharged liquid.

  FIG. 6 is a perspective view in which a plurality of gas suction holes 21 are arranged side by side in one shunt wall body 12. By providing all the gas suction holes 12 so as to be close to a portion having a high negative pressure effect, it is possible to efficiently suck a large amount of gas and supply a large amount of microbubbles.

  The diameter of the gas suction hole 21 is preferably about 0.1 mm to 1 mm.

  FIG. 7 is a photograph showing switching of the discharge direction of the microbubbles in the discharge unit 14.

  The generated microbubbles flow through the network flow path 11 and are discharged while the discharge direction is automatically switched periodically from FIG. 5A to FIG. 5B or in the reverse direction. Since the discharge direction is automatically switched, the microbubbles can be diffused over a wide range without using any diffusion device or the like. In addition, when the flow rate of the fluid is increased, switching of the discharge direction of the microbubbles at the discharge unit 14 is accelerated, and the diffusion of the microbubbles can be further promoted.

  The shunt wall body 12 may be any shape that generates a flip-flop flow, such as an oval shape, but a rhombus prism is particularly preferable. Separation vortices are likely to occur, and the flip-flop flow is stably expressed, so that generation and diffusion of microbubbles can be promoted.

  FIG. 8 is a top view showing a flip-flop flow when the crossing angle of the network flow path 11 is 30 degrees.

  The crossing angle between one group of parallel flow paths and the other group of parallel flow paths is preferably approximately 30 degrees. When the crossing angle of the parallel flow paths is 30 degrees, the aspect ratio a / b in the arrangement interval of the rhomboid prisms is 0.286. When Karman vortex street vibration is regularly appearing behind a single cylinder, it is known that the longitudinal / horizontal spacing ratio of the vortex street is 0.281, but when the crossing angle of parallel flow paths is 30 degrees a / B takes a very close value.

  Further, the next vortex generation position is at the downstream side by La / Lb, which substantially coincides with the arrangement interval of the flow dividing wall bodies 12 here. Along with this, coupled oscillation of the vortex appears, which propagates downstream, and the flip-flop flow also appears stably and regularly, so that the generation and diffusion of microbubbles are promoted.

  Next, the micro mist generator will be described.

  The micro mist generating device is the same device as the above-described micro bubble generating device, and thus illustration is omitted. The gas suction hole in the above-described microbubble generator is used as a liquid suction hole, and gas is used as a distribution medium.

  The generation method is the same as that of the above-described microbubble generator. Gas flows into the network channel from the inflow portion, and the liquid is naturally sucked into the negative pressure portion generated by the ram effect by the flip-flop flow. The sucked liquid is sheared by the flowing gas, and micromist is generated. The generated micro mist is repeatedly diverted and merged by the diverting wall, and is discharged from the discharge portion while the discharge direction is periodically switched.

  A network flow path through a branch wall was used so that the crossing angle of one group of parallel flow paths and another group of parallel flow paths was 30 degrees. Twenty-seven flow dividing wall bodies were arranged in a staggered pattern, and arranged in six rows from the inflow portion to the discharge portion. The rear part of the branching wall bodies in the sixth row from the inflow part was used after being cut so as not to prevent the liquid and microbubbles from being discharged. One gas suction hole having a diameter of 0.5 mm was provided only on one side surface at a location in contact with the joining / dividing branch flow path of one of the diverting wall bodies belonging to the 2nd to 6th rows from the upstream. The thickness of the flow path was 6 mm, and the cross section of the merged / divided branch flow path was a square with a side of 6 mm. Water was allowed to flow at an average flow velocity of 1 m / s at the cross section of the merged / divided branch channel, and the number of bubbles generated and the particle size were measured.

  The gas suction holes were opened in only one row, the other gas suction holes were closed, and the amount of bubbles generated from the gas suction holes in each row was measured. Further, the amount of bubbles generated was measured with the gas suction holes of all rows opened.

  Table 1 shows the amount of bubbles generated in each row.

When the gas suction holes are provided in the fourth row, the amount of generated bubbles is the largest, and as many as 69,400 bubbles / second are generated. When all the gas suction holes are opened, about 130,000 bubbles / second are generated. It is possible to generate bubbles in a superimposed manner by providing gas suction holes in another flow dividing wall body and / or providing a plurality of gas suction holes in one flow dividing wall body.

  FIG. 9 shows the particle size distribution of bubbles generated when the gas suction holes are provided in the fourth row, and Table 2 shows the particle size ratio of the bubbles generated when the gas suction holes are provided in the fourth row. Indicates.

From the particle size distribution, almost all of the generated bubbles are 22 μm or less, and it can be confirmed that they are so-called microbubbles. In addition, it can be seen that bubbles of 13 μm or less account for 50% or more, and the generation rate of microbubbles effective for the physiological activity is high. Furthermore, the peak value is 10 to 20 μm, and it can be confirmed that the bubbles are small in size as a whole and bubbles having a uniform particle size.

  A drop in the peak value is observed at a particle size of several tens of μm. It is known that the dissolved gas contained in the water flowing through the flow path is separated along with the separation vortex to generate bubbles, but the particle size of the bubbles generated along with the separation vortex varies depending on the flow velocity and the like. When the flow path is large, bubbles generated along with the separation vortex increase, so that bubbles having a diameter smaller than the peak value of the drop are microbubbles generated from the gas suction hole, and most of them are microbubbles having a diameter of 10 tens μm or less It can be confirmed that

  The microbubble generator according to the present invention is a device that can generate a large amount of microbubbles having a particle size of 10 μm or less by using a flip-flop flow, and can diffuse microbubbles over a wide range. And can be used in many fields including aquaculture.

  In addition, the micromist generator according to the present invention can be applied to various fields such as supply of negative ions because micromist can be diffused and discharged in a large amount.

It is a perspective view of the microbubble generator of the present invention. It is a perspective view which shows a cross section of a confluence / diversion branch flow path. It is a top view which shows the generation | occurrence | production location of the ram effect in a network flow path. It is a water head pressure measurement figure in the cross section of a merging / dividing branch flow path. It is a flow-velocity distribution map which shows the average flow velocity of the liquid in the back of the branch wall body of the 3rd row | line and 5th row | line from an apparatus upstream. It is a perspective view of a flow dividing wall body provided with a plurality of gas suction holes. It is a photograph which shows switching of the discharge direction of the microbubble in a discharge part. It is a top view which shows the flip-flop flow with a network flow path crossing angle of 30 degrees. It is a particle size distribution map of the microbubble generated by this device. 6 is a particle size distribution diagram of microbubbles generated by the microbubble generator described in Patent Document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microbubble generator 11 Network flow path 12 Divided wall body 13 Liquid inflow part 14 Liquid discharge part 21 Gas suction hole 31 Merge / diversion branch flow path

Claims (3)

A network flow path that generates a flip-flop flow by joining and diverting a group of parallel flow paths and another group of parallel flow paths on the same plane via a number of diversion wall bodies, and facing the adjacent diversion flow A plurality of gas suction holes are arranged side by side on the side wall of the flow dividing wall body at a position closest to the wall body, and a plurality of the gas suction holes are placed close to a place having a high negative pressure effect. A microbubble generator characterized in that the amount of microbubbles generated is increased by inhaling gas.   The microbubble generator according to claim 1, wherein the diameter of the gas suction hole is 0.1 mm to 1 mm. A network flow path that generates a flip-flop flow by joining and diverting a group of parallel flow paths and another group of parallel flow paths on the same plane via a number of diversion wall bodies, and facing the adjacent diversion flow A plurality of liquid suction holes are arranged side by side on the side wall of the flow dividing wall body at the closest position, and a plurality of the liquid suction holes are placed in close proximity to a portion having a high negative pressure effect. A micro mist generator characterized by increasing the amount of droplets generated by sucking liquid from