JP2972093B2 - Gas-liquid dissolving and mixing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-liquid dissolving / mixing apparatus for mixing and dispersing a gas as a gas bubble in a liquid and for efficiently dissolving the gas in the liquid.

[0002]

2. Description of the Related Art Heretofore, Japanese Patent Application No. Hei.
As shown in FIGS. 8 and 9, the gas-liquid dissolving and mixing apparatus shown in No. 73 and the like has a mixer 81 for flowing a gas into a liquid and mixing it. Inlet 8 of this mixer 81
4 is provided with a distal end of a pipe 12 for supplying a liquid, and an outlet 94 of the mixer 81 is connected to a pipe 20 which also serves as a pressurized mixing section for pressurizing and mixing the gas and the liquid.
A nozzle 22 is connected to the tip of the pipe 20.
Further, the mixer 81 is formed with a gas inlet 82 for sucking and flowing gas.

As shown in FIG. 9, a venturi-shaped flow path 86 having a throat 88 at the center thereof is formed concentrically inside a mixer 81. Downstream of the throat portion 88, a gas inflow portion 90 having a slightly larger inner diameter than the throat portion 88 and having a predetermined length and a constant cross-sectional area is provided. The gas inflow portion 90 is provided subsequent to the gas inflow portion 90 and flows downstream. A widening portion 92 that widens the road is formed. In the gas inflow portion 90, a gas inflow hole 96 connected to the gas inlet portion 82 is opened.

[0004]

In the case of the above prior art, as the flow rate of the liquid increases, the proportion of the gas sucked from the gas inlet 82 for sucking the gas decreases.
The flow rate capable of maintaining the ratio of the gas capable of efficiently dissolving and mixing the gas and liquid was such that the liquid flow rate was 12 m ³ / h or less, and the maximum throughput of the liquid in one channel 86 was small. This is because, in order to increase the liquid flow rate, the flow path 86 may be enlarged as a whole. However, the liquid flow rate increases in proportion to the cross-sectional area of the flow path, and the gas flowing into the flow path 86 has a certain thickness. This is because the flow path has a positive correlation with the length of the outer peripheral edge of the flow path, and the larger the flow path, the lower the proportion of the gas mixed into the liquid.

In the above-mentioned conventional technique, when two or more kinds of gases are to be sucked into a liquid, the gases interfere with each other at a gas inlet portion 82, and the flow rates of the two kinds of sucked gases and Adjusting the pressure was very difficult.
In particular, when one gas supply source is air under atmospheric pressure and the other supply source is from a cylinder, etc., it is necessary to attach a regulator to make the pressure equal to the atmospheric pressure in the cylinder. Became. Further, since the atmospheric pressure changes due to a change in weather, it is necessary to adjust the flow rate and the pressure of the liquid according to the change in the atmospheric pressure.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has a simple structure, a high gas mixing efficiency, and a gas-liquid dissolving / mixing apparatus capable of easily inflow of a plurality of gases. The purpose is to provide.

[0007]

According to the present invention, at least a part of the plurality of parallel flow paths is formed by forming a branch point in which a plurality of flow paths are branched in parallel in the middle of the flow path through which the liquid flows. In the flow path, a throttle portion such as a venturi tube or an orifice is provided, and a gas inflow portion provided in a downstream side of the flow channel and having an equal cross-sectional area in a fluid flow direction direction is provided following the throttle portion. A gas inflow hole for allowing gas to flow in from the outside is formed, and a divergent portion in which a flow path is gradually widened is provided downstream of the gas inflow portion. Forming a merging point to be merged, provided with a pressurized mixing unit for pressurizing and mixing the liquid in the flow path and the gas flowing from the gas inflow hole downstream of the merging point,
This is a gas-liquid dissolving and mixing apparatus provided with a nozzle on the outlet side of the pressurized mixing section.

[0008] Further, the invention is characterized in that the throttle portion downstream from the branch point, the gas inflow portion, the gas inflow hole,
A gas-liquid dissolving and mixing device in which the expanding portion and the junction are formed in an integrated suction device. Further, the suction device and the nozzle portion are connected by a pipe also serving as the pressure mixing portion. Furthermore, the above-mentioned between the above- mentioned suction device and the above-mentioned nozzle part
In the middle of the pipe, a flow path having a shape that flows down stepwise from the top is provided, and in the middle of the pipe before the nozzle portion, a branch flow path that protrudes upward and removes excess gas is provided. Further, each of the throttle section, the gas inflow section, and the gas
An inflow hole and the widening portion are provided, and the size of the throttle portion and the gas inflow portion is made different for each flow path, and a different gas is supplied to each of the gas inflow holes downstream of the branch point. Things.

[0009]

In the gas-liquid dissolving and mixing apparatus of the present invention, a plurality of flow paths are branched in parallel, and the static pressure of the liquid in the flow paths is reduced by a throttle provided in the middle of the branched flow paths. The gas is introduced from a slightly downstream gas inlet to form a gas-liquid mixed flow. Then, in the pressurized mixing section downstream thereof, the flow is slowed and the static pressure is increased, so that the inflowing gas is dissolved in the liquid.
Furthermore, the nozzle at the outlet of the pressurized mixing section accelerates the gas-liquid mixed flow to lower the static pressure again, precipitates dissolved gas from the liquid as microbubbles, and flows when passing through the nozzle. Due to the turbulence, bubbles that have not been completely dissolved are sheared and subdivided to generate microbubbles.

In addition, a gas and a liquid can be dissolved with high efficiency by a flow path which flows down in a stepwise manner, and a surplus gas can be exhausted to obtain a liquid foamed only by microbubbles in which the dissolved gas is deposited. it can. Furthermore, different types of gases are sucked from the gas inlets connected to different gas inlets of the gas-liquid dissolving and mixing device, and the gas inlets are independent of each other, so that the flow rate of the sucked different types of gas or The pressures can be easily controlled without interfering with each other.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a gas-liquid dissolving and mixing apparatus according to the present invention will be described below with reference to the drawings. 1, 2, and 3
FIG. 1 shows a gas-liquid dissolving and mixing apparatus according to a first embodiment of the present invention, in which a water tank 10 serving as a water or other liquid supply unit and a pump 14 for pressure-feeding the liquid are connected by a pipe 12.
A pipe 16 is also connected to the discharge side of the pump 14,
Is connected to a liquid inlet 34 of the suction device 18 that allows gas such as air to flow into the liquid flow. The outlet 20 of the aspirator 18 is connected to a pipe 20 which also serves as a pressurizing and mixing unit for pressurizing and mixing the gas and the liquid, and a nozzle 22 is attached to a tip of the pipe 20. The pipe 20 may be a flexible pipe or a hard pipe such as a steel pipe. The nozzle 22 is connected below a foaming liquid tank 24 that stores the foamed liquid.

The suction device 18 is provided with gas inlets 28 at two places on its side surface, and flow control valves 32 are connected to the gas inlets 28 via pipes 30, respectively. The upstream side of the flow control valve 32 is connected to a gas supply source such as a cylinder or the atmosphere (not shown) via a pipe (not shown). In this embodiment, there are two flow control valves 32, but they may be connected to the same gas supply or to different gas supplies. In the case of sucking air, the piping on the upstream side of the flow control valve 32 may be released to the atmospheric pressure. If the gas flow does not need to be adjusted, the flow control valve 32 may be omitted.

FIG. 2A shows a suction device 18 of this embodiment.
As shown in (B), the suction device 18 is formed integrally, and the liquid flow path branches in parallel at a branch point 36 inside the inlet portion 34. Here, in the drawing of this embodiment, the branch point 3
In 6, the flow path is branched into two flow paths, but may be branched into three or more flow paths. A venturi tube 38 is formed in each of the flow paths after branching, the flow path having a throat 40 forming a throttle at the center. Downstream of the throat portion 40, there is provided a gas inflow portion 42 having a slightly larger inner diameter than the throat portion 40 and having a cylindrical shape having a constant cross-sectional area by a predetermined length in the fluid flow direction. A gas inflow hole 50 into which gas flows is provided at a position slightly downstream of the throat 40 of 42. Then, each of the branched flow paths joins at the junction 46 after the gas inflow section 42 and the expansion section 44.

FIG. 3 shows a nozzle 22 of this embodiment.
As shown in (A) and (B), a plurality of nozzle holes 54 are provided on the end face and side face of the nozzle 22. Although a plurality of nozzle holes 54 are shown in the drawing, a single hole may be used.
In the drawing, the nozzle hole 54 has a fixed throttle shape.
A variable throttle such as a valve may be used.

Next, the operation of the gas-liquid dissolving and mixing apparatus of this embodiment will be described below. The liquid in the water tank 10 is pumped to the suction device 18 by the pump 14. The liquid that has flowed into the liquid inlet 34 of the suction device 18 branches into two flow paths at a branch point 36, and is accelerated in each flow path by the throat 40 of the venturi tube 38, and once the static pressure decreases, the gas The static pressure increases again through the inflow section 42 and the expansion section 44. After the spreading part 44,
The branched channels merge again at the junction 46.
Here, when the liquid flows through the venturi tube 38,
Gas flows into the liquid stream from the gas inlet 50 slightly downstream of the throat 40 where the static pressure is relatively low. Since the gas inflow portion 42 is only slightly wider than the throat portion 40, the static pressure in this portion is also relatively low, and the gas flows through the flow control valve 32, the pipe 30, the gas inlet portion 28, and the gas inflow hole. 5
After that, it flows into the flow path of the suction device 18 through 0. Here, the reason why the gas inlet hole 50 is not provided in the throat portion 40 is a portion where the throat portion 40 has the lowest static pressure. However, if the gas inlet hole 50 is provided in the throat portion 40, gas suction is good. Because there is no.

The gas flowing into the liquid flow from the gas inlet 50 becomes bubbles and the liquid in the flow path together with the suction device 18.
Flows into the outlet section 48, and the flows branched at the joining point 46 join and flow into the pipe 20 also serving as the pressurizing and mixing section. Piping 20
Inside, the static pressure of the flow becomes relatively high, so that the gas that has become bubbles dissolves in the liquid. Then, the liquid is ejected from the pipe 20 through the nozzle hole 54 of the nozzle 22 into the foaming liquid 26 together with the bubbles. When passing through the nozzle hole 54, the liquid is accelerated again, so that its static pressure is reduced,
The gas dissolved in the liquid precipitates as microbubbles.
Further, the bubbles that have not been completely dissolved are also subdivided by the shearing force due to the turbulence of the flow when accelerated by the nozzle holes 54, and are released together with the liquid as small-diameter bubbles.

The total sum of the cross-sectional area of the throat 40, the cross-sectional area of the gas inflow section 42, the cross-sectional area of the nozzle hole 22, and the cross The relationship of the sum of the areas may be any as long as the following expression is satisfied. PAn <PGn (1) PGn (n is a natural number and corresponds to each gas inflow section 42)
Is the pressure of the gas flowing from each gas inlet hole 50. PAn is a static pressure of each gas inflow portion 42 given by the following equation according to a fluid dynamics continuous equation and Bernoulli's theorem. PAn = ｛1- (SAn ² SC ² ) / (SA ² SB
n ² ) {P1 + (δP + PB)} (SAn ² SC ² ) /
(SA ² SBn ² )｝ (2) where SA
Is the sum of the cross-sectional areas of the throats 40, SAn is the cross-sectional area of each throat 40, SBn is the cross-sectional area of each gas inlet 42, SC is the sum of the cross-sectional areas of the nozzle holes 54, and P1 is the total of the gas inlets 42. Pressure,
δP is the pressure loss from the suction device 18 to the nozzle 22, PB
Is the static pressure at the outlet of the nozzle hole 54.

Therefore, by setting the size of each of the gas inflow section 42 and the nozzle hole 54 so as to satisfy the above equations (1) and (2), optimum conditions for efficiently mixing and dissolving in the liquid are obtained. Is obtained. Further, the pipe 20 also serving as the mixing section is more preferably provided that a gas-liquid contact time until gas is dissolved and saturated in a liquid under pressure is obtained, and the gas-liquid contact time depends on the volume of the pipe. Therefore, the longer the length of the pipe is, the more the gas will be dissolved to the saturation point. If it is not necessary to dissolve the gas to the saturation point, the pipe 20 may be short.

When the gas-liquid dissolving and mixing apparatus of this embodiment is used, the maximum processing amount is experimentally about 25 m ³ / h or more,
About twice as much processing as the conventional one is possible. When the number of flow paths such as the venturi tube 38 is increased, the processing flow rate is increased in proportion to the number. Further, air supplied from under atmospheric pressure and carbon dioxide supplied from a cylinder were sucked into the different gas inlets 28 of the gas-liquid dissolving and mixing apparatus of this embodiment at a ratio of 1: 2. With simple adjustments, this ratio could be maintained continuously.

According to the gas-liquid dissolving and mixing apparatus of this embodiment,
A liquid having an optimal flow rate for dissolving and mixing gas-liquid can be flown for each flow path, and air and other gases can be efficiently mixed in the liquid. In addition, since a plurality of flow paths are formed in the integrated suction device 18, the structure is simple, and handling and installation are easy.

The suction device 18 shown in FIG.
4, a junction 46 is provided.
A junction 46 may be provided directly downstream of the gas inflow section 42. Further, the amount of gas flowing from the gas inflow section 42 can be adjusted by the gas flow rate control valve 32.
In particular, since the gas inlet 42 in the suction device 18 is independent, in the gas-liquid dissolving and mixing apparatus of this embodiment,
The gas flow flowing from the gas inlet 28, which plurality of can be adjusted independently by using a gas flow rate control valve 32.

Next, a second embodiment of the present invention will be described with reference to FIG. The same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, a gas inflow hole 50 is formed in a gas inflow portion 42 slightly downstream of a throat portion 40 which is one of the two flow paths formed in the suction device 18. In the other flow path 55, a portion into which gas flows is not formed.

According to this embodiment, only the minimum necessary gas can be efficiently dissolved and mixed in the liquid, and the waste of the gas can be reduced. However, even in this case, the throat 40 and the gas inlet 42 must be formed in at least one flow path.

Next, a third embodiment of the present invention will be described with reference to FIG. The same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, the flow path 38 of the suction device 18 has a different inner diameter as shown in FIG. In this case, in the large flow path 56 having a large inner diameter, a large amount of gas is sucked from the gas inlet 28,
In the flow path 58 having a small inner diameter, a small amount of gas is sucked from the gas inlet 28.

According to the gas-liquid dissolving and mixing apparatus of this embodiment,
When the amount of gas to be sucked from each gas inlet portion 28 is largely different, the gas and liquid can be mixed with optimum efficiency by changing the size of the liquid flow path, and the gas and liquid can be used without waste. Can be.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, a gas-liquid mixing tank 60 having a flow path 62 in which a fluid flows repeatedly and gradually in a stepwise manner and flows down is provided between the pipes 20 also serving as the mixing section of the first embodiment. Therefore, the suction device 18 is attached to the upstream side of the mixing tank 60 via a pipe 68, and the nozzle 22 is attached to the downstream side of the mixing tank 60 via a pipe 69.

In this embodiment, the gas-liquid mixing tank 60 has a flow path 62 that flows down repeatedly and gradually in a stepwise manner. When a gas-liquid mixed flow is passed through this flow path 62, the gas Then, the liquid flows into the lower portion, and a flow having a large gas-liquid contact area can be obtained. Further, since the position of the outlet portion 66 is lower than the inlet portion 64 into which the gas-liquid mixed flow flows,
The low-density gas is stagnated in the flow channel 62, and the ratio of the gas inside the mixing tank 60 is high even when the ratio of the gas is relatively low at the stage of flowing into the gas-liquid mixing tank 60. For this reason, highly efficient gas dissolution is performed inside the gas-liquid mixing tank 60.

Next, a fifth embodiment of the present invention will be described with reference to FIG. The same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, an excess gas venting section 70 for evacuating excess gas is provided between the pipes 71 and 75 in front of the nozzle 22 of the first embodiment. Inside the surplus gas vent 70, a branch flow path 74 is formed between the inlet 72 and the outlet 76 and protrudes upward. At the end of the branch flow path 74, a valve 78 for adjusting the flow rate of the surplus gas to be discharged and an exhaust pipe 80 are attached. In this embodiment, the valve 78 is used. However, when the surplus gas to be discharged is caused to flow through the branch flow path 74 at a constant pressure, a fixed throttle having an appropriate size or a pipe having a pipe resistance equivalent to that of the valve 78 is used. You may.

The function of the surplus gas vent 70 in this embodiment is as follows. In the gas-liquid mixed flow flowing from the inlet 72 of the surplus gas vent 70, the gas floats upward from the branch passage 74 projecting upward. . After that, the gas is
The air is exhausted from the exhaust pipe 80 through the exhaust pipe 8. Here, by appropriately adjusting the throttle of the valve, the exhaust can be performed without changing the internal pressure. By providing the surplus gas vent 70, the air bubbles mixed in the liquid can be made only air bubbles having a diameter of several μm to several tens μm.

[0030]

According to the gas-liquid dissolving and mixing apparatus of the present invention,
A liquid at an optimal flow rate for gas-liquid dissolution and mixing is caused to flow through each flow path, so that air and other gases can be efficiently mixed in the liquid. Further, since the suction device is formed integrally and a plurality of flow paths are formed in the suction device, the structure is simple, the strength is high, and the handling and installation are easy.
Furthermore, since the gas is caused to flow into the different liquid flow paths, the flow rate or the pressure of the gas can be easily controlled without interfering with each other.

Further, by providing a flow path that flows down in a stepwise manner, gas can be dissolved in liquid with high efficiency, and a small amount of gas can be dissolved in liquid without waste. Further, by evacuating the surplus gas, a foaming liquid of fine bubbles can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a gas-liquid dissolving apparatus according to a first embodiment of the present invention.

FIG. 2 is a side view of the suction device according to the first embodiment of the present invention (A).
(B) of FIG.

FIG. 3 is a side view (A) showing a nozzle according to a first embodiment of the present invention, and a sectional view 1 (B) in a flow channel direction.

FIG. 4 is a side view (A) showing a suction device of a gas-liquid dissolving apparatus according to a second embodiment of the present invention, and a cross-sectional view (B) in a flow channel direction.

FIG. 5 is a side view (A) and a cross-sectional view (B) showing another type of suction device according to the third embodiment of the present invention.

FIG. 6 is a configuration diagram including a cross-sectional view of a gas-liquid mixing tank according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view of a fifth embodiment of the present invention in which excess gas is vented.

FIG. 8 is a configuration diagram of a conventional gas-liquid dissolving and mixing apparatus.

FIG. 9 is a side view (A) of a mixer of a conventional gas-liquid dissolving and mixing apparatus and a cross-sectional view (B) in a flow channel direction.

[Explanation of symbols]

 12, 20, 30 Piping 18 Suction device 22 Nozzle 36 Branch point 38 Venturi tube (flow path) 40 Throat (throat portion) 42 Gas inflow portion 44 Expanding portion 46 Junction point 50 Gas inflow hole 54 Nozzle hole

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-328402 (JP, A) JP-A-7-308556 (JP, A) JP-A-7-60088 (JP, A) JP-A-6-208 63371 (JP, A) JP-A-6-285345 (JP, A) JP-A-6-285344 (JP, A) JP-A-6-269651 (JP, A) JP-A-62-1151939 (JP, U) (58) Field surveyed (Int.Cl. ⁶ , DB name) B01F 1/00-5/26

Claims (7)

(57) [Claims] 1. A flow path in which a liquid flows, forms a branch point where the flow paths are branched in parallel, and a throttle portion is provided in at least a part of the flow paths that are branched in parallel. Subsequent to the throttle portion, a gas inflow portion having a slightly larger inner diameter than the throttle portion and having a predetermined length and a constant cross-sectional area in the flow direction of the fluid is provided downstream of the flow channel. Providing a gas inflow hole for inflowing gas from the outside,
Downstream of the gas inflow section is provided a widening portion in which the flow path is gradually widened, and at the widening section or downstream thereof, a merging point is formed to merge the plurality of parallelly branched flow paths again, and downstream of this merging point. A gas-liquid dissolving / mixing apparatus comprising: a pressurizing / mixing unit for pressurizing and mixing a liquid in a flow path and a gas flowing from the gas inflow hole, and a nozzle at an outlet side of the pressurizing / mixing unit. 2. The throttle section downstream from the branch point,
2. The gas-liquid dissolving and mixing apparatus according to claim 1, wherein the gas inflow portion, the gas inflow hole, the expanding portion, and the confluence point are formed as an integrated suction device. 3. The gas-liquid dissolving and mixing apparatus according to claim 2, wherein the suction unit and the nozzle are connected by a pipe also serving as the pressurizing and mixing unit. 4. The arrangement between the suction device and the nozzle portion.
4. The gas-liquid dissolving and mixing apparatus according to claim 3, wherein a flow path having a shape that flows down stepwise from above is provided in the middle of the pipe . 5. The gas-liquid dissolving / mixing apparatus according to claim 3, wherein a branch flow path for projecting upward and extracting excess gas is provided in the middle of the pipe on the upstream side of the nozzle section. 6. The throttle section, the gas inflow section, and the gas flow section in each of the plurality of parallel flow paths of the suction device.
3. The gas-liquid dissolving and mixing apparatus according to claim 2, wherein a body inflow hole and the widening portion are provided, and the size of each of the constricted portions and the gas inflow portion is different for each flow path. 7. A gas inlet section is provided in each of the plurality of parallel flow paths of the suction device, and a different gas is supplied to each of the flow paths to the gas inlet section connected to each of the flow paths. Item 3. A gas-liquid dissolving and mixing apparatus according to Item 2.