JP2554608B2 - Gas-liquid dissolution mixing method and gas-liquid dissolution mixing device - 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 method and a gas-liquid dissolving / mixing apparatus for mixing and dispersing bubbles in a liquid or efficiently dissolving a gas in the liquid.

[0002]

2. Description of the Related Art Conventionally, as a device for dispersing and dissolving a large amount of gas in a liquid, there is a so-called ejector type bubble generating device. This is the liquid jet ejected from the nozzle,
Once passing through the gas to be mixed, the gas mixing jet flow is jetted into the water tank from the throttle provided coaxially with the nozzle and having a diameter substantially equal to the jet flow to mix micro bubbles in the liquid. In addition, a gas in which micro bubbles are dispersed by the same method is injected into the lower part of the bubble column, a large amount of gas is dissolved in the liquid while the micro bubbles rise in the liquid, and the liquid in which the desired gas is dissolved is It was manufactured. On the other hand, there is also one in which gas and liquid are fed into a pressure pump to pressurize the liquid in the pressure pump and dissolve gas from bubbles in the liquid into the liquid.

[0003]

In the case of the ejector-type bubble generating device of the above-mentioned prior art, the center of the liquid jet nozzle and the center of the diaphragm must be coincident with each other, the structure of the device is complicated and the manufacture is difficult, The mixing ratio of gases and improvement in usage were not sufficient. Further, the gas dissolving device using the bubble column has a long rise time until a liquid in which the gas is sufficiently dissolved is obtained, and the manufacturing efficiency is not good. Furthermore, in the case of using the above-mentioned conventional pressure pump,
Since gas and liquid are sent into the pressurizing pump together, there is a problem that cavitation is likely to occur in the pump and the material and structure of the pump are limited.

The present invention has been made in view of the above-mentioned problems of the prior art. It is possible to efficiently obtain fine bubbles with a simple structure and to mix and dissolve a large amount of gas in a liquid. An object of the present invention is to provide a gas-liquid dissolving and mixing method and a gas-liquid dissolving and mixing apparatus that can perform the above.

[0005]

According to the present invention, a part of a liquid flow path is throttled by a Venturi tube, an orifice or the like, the pipe path is gradually widened on the downstream side of the throttle part, and slightly downstream of the throttle part. Gas is introduced at the side, and the gas and the liquid are melted and mixed under pressure at the downstream side of the expanded portion, and a gas-liquid mixed flow is jetted from a nozzle portion provided at the outlet and the gas dissolved in the liquid is discharged. This is a gas-liquid dissolution mixing method for precipitation. In addition, a venturi tube or an orifice provided in the liquid flow path
A narrowed portion such as a fiss, a widened portion that gradually widens the pipe line following the narrowed portion, a gas inlet provided in the widened portion slightly downstream of the narrowed portion, and a downstream portion of the widened portion. The liquid in the channel provided and the gas flowing in from the gas inlet are under a pressure higher than the pressure of the gas at the gas inlet.
In comprising a mixing unit for dissolving and mixing, and a nozzle portion precipitating the gas dissolved in the liquid with shear the bubbles ejected gas-liquid mixed flow provided at the outlet of the mixing section, the gas flow
The pressure of the gas flowing in from the inlet is the static pressure at the outlet of the nozzle.
If the pressure is less than or equal to the pressure,
From the cross-sectional area of the widened part, disconnect the nozzle port of the nozzle part.
While setting so that the total area is larger,
Static at the widened part at the connection part of the gas inlet
From the pressure, the spread at the connection point of the gas inlet
So that the static pressure of the liquid in the
It is a gas-liquid dissolution mixing device in which the total cross-sectional area of the above is set .

Further, according to the present invention, the static pressure P _A at the widened portion at the connecting portion of the gas inflow port given by the following equation by the continuity of fluid dynamics and Bernoulli's theorem is S _A is gas The cross-sectional area of the above-mentioned widened portion at the connection portion of the inflow port, S _B is the total cross-sectional area of the nozzle port, P
₁ is the total pressure of the expanded portion at the connection portion of the gas inlet, δP is the pressure loss from the expanded portion to the nozzle portion at the connection portion of the gas inlet, P _B is the static pressure at the outlet of the nozzle portion Then, P _A = (1−S ² _B / S ² _A ) P ₁ + (δP + P _B ) S ² _B / S ² _A , and the pressure P _{G of} the gas flowing in from this P _A and the gas inlet. And P satisfy P _A <P _G. Further, the above-mentioned slip portion has a plurality of nozzle openings formed therein, and the throttle portion and the nozzle portion are connected by a pipe line which also serves as a mixing portion.

[0007]

The gas-liquid dissolving and mixing method and the gas-liquid dissolving and mixing device of the present invention allow gas to flow into a flow from a negative pressure portion slightly downstream of a throttle portion such as a throat portion of a Venturi tube, and the flow becomes slow. The gas flowing in the mixing section with increased static pressure is pressurized and dissolved, and further, the gas-liquid mixed flow is accelerated by the nozzle section at the outlet, and due to the turbulence of the flow at this time, the mixed bubbles are sheared and fragmented. At the same time, bubbles are generated by precipitating dissolved gas from the liquid as fine bubbles.

[0008]

Embodiments of the gas-liquid dissolving and mixing method and the gas-liquid dissolving and mixing apparatus of the present invention will be described below with reference to the drawings.
1 and 2 show a first embodiment of the present invention.
As shown in (1), the mixer 10 for mixing gas into a liquid is provided with a Venturi tube 14 having a throat portion 12 as a throttle portion provided in the central portion. This venturi tube 14
In the widened portion 16 on the downstream side of the throat portion, a gas inlet port 18 for mixing gas in the flow path is provided on the slightly downstream side of the throat portion 12.
Are formed.

On the downstream side of the expanded portion 16, the gas inlet 1
A mixing portion 20 for mixing the gas flowing in from 8 and the liquid in the flow path is formed. The outer diameter of the mixing portion 20 can be arbitrarily set in accordance with the degree of pressurization, and here, the mixing portion 20 is formed in a shape extending from the maximum diameter of the widening portion 16, and a plurality of tips are formed at the tip of the mixing portion 20. A nozzle portion 24 having a nozzle opening 22 is attached.

The operation of the gas-liquid dissolving and mixing apparatus of this embodiment will be described below. First, the liquid that has flowed into the inlet portion 26 of the mixer 10 is accelerated in the throat portion 12 of the Venturi tube 14, and the static pressure is once reduced, and then the flow velocity is slowed through the widening portion 16 and the static pressure is increased again. At this time, the gas inlet 18
Is slightly downstream of the throat portion 12, and the static pressure in this portion is relatively negative, so that gas flows into the flow path. The gas inlet port 18 is not arranged in the throat portion 12 where the throat portion 12 has the lowest static pressure. However, when the gas inlet port 18 is provided in the throat portion 12, the gas suction is not good and the throat portion 12 does not flow. This is because gas can flow in more easily where the passage begins to expand.

The gas flowing from the gas inflow port 18 flows as bubbles into the mixing section 20 together with the liquid in the flow path, and the bubbles become liquid because the static pressure of the mixing section 20 is higher than that of the throat section 12. Dissolves in. Then, the liquid is ejected from the mixing unit 20 through the nozzle port 22 together with the bubbles. When passing through the nozzle port 22, the liquid is accelerated again, so that the static pressure becomes low and the gas dissolved in the liquid is deposited as fine bubbles. Further, the bubbles that are not completely dissolved are also subdivided due to turbulence of the flow when accelerated at the nozzle port 22 and become bubbles with a small diameter and are ejected together with the liquid.

In the gas-liquid dissolving and mixing apparatus of this embodiment, the widened portion 16 at the connecting portion of the gas inflow port 18 and the nozzle port 2
The relationship with the sum of the cross-sectional areas of 2 may satisfy the following formula. P _A <P _G (1) P _G is the pressure of the gas flowing in from the gas inlet 18. P _A is the static pressure of the liquid at the widened portion 16 at the connection site of the gas inlet 18 given by the following equation according to the equation of continuity in hydrodynamics and Bernoulli's theorem.

P _A = (1-S ² _B / S ² _A ) P ₁ + (δ
P + P _B ) S ² _B / S ² _A (2) Here, S _A is a cross-sectional area of the expanded portion 16 at the connection portion of the gas inlet port 18,
S _B is the total cross-sectional area of the nozzle port 22, P ₁ is the total pressure of the expansion part 16 at the connection part of the gas inlet 18, δP is the pressure from the expansion part 16 at the connection part of the gas inlet 18 to the nozzle port 22. The loss, P _B, is the static pressure at the outlet of the nozzle port 22.

Therefore, by setting the sizes of the widening portion 16 and the nozzle opening 22 at the connecting portion of the gas inlet 18 so as to satisfy the above equations (1) and (2), the gas can be efficiently introduced into the liquid. The optimum conditions for mixing and dissolving are obtained. Specifically, the equation (2) is inserted into the equation (1),
Further, if P _G = kP _B (k> 0), the following equation
(3) can be derived. 0> δP · S ² _B / S ² _A + (S ² _B / S ² _A −k) P
^{_{B + (1-S 2 B}} / S 2 A) P 1 = δP · S 2 B / S 2 A + (1-k) P B + (1-S 2 B / S 2 A) · (P 1 - P _B ) ... (3) In this equation (3), the pressure loss δP is a positive value and
The first term is a positive value. Also, normally, from the gas inlet 18
The pressure P _G of the inflowing gas is the static pressure at the outlet of the nozzle port 22.
It is a value less than or equal to P _B , in which case k is 0 <k ≦ 1.
is there. Then, the second term of the above formula (3) is also 0 or more.
Therefore, the third term of equation (3) must be negative,
In that case, the widened portion at the connection portion of the gas inlet port 18
The total pressure P _{1 of} 16 is naturally the outlet of the nozzle port 22 on the downstream side.
Is larger than the static pressure P _{B of}
(3) the third term of ^{_{(1-S 2 B / S}} 2 A) sounds a negative value
I have to. From the above, S ² _B / S ² _A > 1
Of the expanded portion 16 at the connection portion of the gas inlet 18
The cross-sectional area S _A is the sum of cross-sectional areas S _B of the nozzle openings 22
Must be set large. Also, the gas inlet 1
The pressure P _{G of} the gas flowing in from 8 is the outlet of the nozzle port 22.
If the static pressure is larger than P _B (k> 1), the above pressure loss
Considering δP etc., gas as appropriate so as to satisfy equation (3)
Cross-sectional area S of the widened portion 16 at the connection portion of the inflow port 18
Than _A, decreases towards the sum S _B of the cross-sectional area of the nozzle opening 22
Or vice versa. For the setting of the nozzle port 22, a plurality of types of nozzle portions 24 having a fixed diameter of the nozzle port 22 are prepared and appropriately selected from those, or the nozzle port 22 is processed and formed each time. Alternatively, it goes without saying that a nozzle unit 24 having a variable nozzle port 22 may be used. Further, the mixing section 20 is more preferable as long as it can obtain a gas-liquid contact time until the gas is dissolved and saturated in the liquid under pressure, and the gas-liquid contact time depends on the volume of the mixing section. The gas dissolves up to the saturation point when the length of the mixing part is longer to some extent. Further, when it is not necessary to dissolve the mixture to the saturated state, the mixing section 20 may be short.

Using the gas-liquid dissolution mixing apparatus of this embodiment,
The gas-dissolved water production apparatus will be described with reference to FIG.
The apparatus for producing gas-dissolved water according to this embodiment is provided with a water tank 30 and a pump 32 for pumping a liquid connected by a pipe line 34, and the mixer 10 is connected to the output side of the pump 32 through a pipe line 36.
Is attached. The mixer 10 is attached to the bottom of a water tank 38 for accumulating a liquid in which a gas is dissolved, with a nozzle portion 24 opened, and a gas tank 44 at a gas inlet 18 thereof via a pipe 40 and a flow rate adjusting valve 42. It is connected. Further, a pipeline 48 connected to the water tank 30 via a relief valve 46 is connected to the pipeline 36.

In this apparatus for producing gas-dissolved water, the liquid in the water tank 30 is pumped to the mixer 10 by the pump 32, and the gas sent from the gas tank 44 in the mixer 10 is in the mixer 10 as described above. Is mixed with the liquid, and a large amount of gas is dissolved in the liquid, and the gas is ejected from the nozzle 22 together with the bubbles. Here, the relief valve 46 is for making the pressure of the liquid to be pumped constant, and the flow rate adjusting valve 42 is for adjusting the gas flow rate so that minute bubbles are efficiently formed in the liquid. It is a thing. Experimentally, when the gas flow rate was 10 to 30% of the liquid flow rate, a large amount of small-sized bubbles were efficiently obtained in the liquid. The bubbles jetted from the mixer 10 are dispersed in the liquid in the water tank 38 by the jet flow, and are fine bubbles, so that they are suspended in the liquid for a long time. In this gas-dissolved water production apparatus, when it is desired to always disperse air bubbles in the liquid, the water tank 30 and the water tank 38 may be connected in the same manner as the conduits 34, 36.

Using the gas-liquid dissolving and mixing apparatus of this embodiment,
Table 1 shows the experimental results obtained by dissolving ozone in water. Here, the ozone generation amount is 10,000 ppm, and a 0.7 m long stainless steel pipe is used for the mixing portion 20 of the mixer 10.

[0018]

[Table 1]

In Table 1, the starting time is the rising time until the ozone water having a predetermined concentration can be continuously produced after the start of the apparatus, and when the conventional bubble column is used. Compared with the rise time of about 30 minutes, the gas-liquid dissolving and mixing apparatus of this example can efficiently produce gas-dissolved water in an extremely short time.

Next, a second embodiment of the present invention will be described with reference to FIG. Here, the same members as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. In the mixer 50 of this embodiment, a main body portion 52 in which the venturi pipe 14 that is a throttle portion is formed and a nozzle portion 54 in which a nozzle port is formed are separated, and a pipe line 56 that connects them is a mixing portion. It is what

The pipe 56 may be a steel pipe or a flexible pipe, and the gas and the liquid are mixed more efficiently when the flow becomes a turbulent flow. The Reynolds number of 56 may be set to a value equal to or higher than a value that causes turbulence.

According to the gas-liquid dissolving and mixing apparatus of this embodiment,
The position of the nozzle portion 54 can be freely set, and only the nozzle portion 54 can be freely moved, so that the degree of freedom is increased.

Next, a third embodiment of the present invention will be described with reference to FIG. Here, the same members as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. The mixer 60 of this embodiment includes a throat portion 12 of the Venturi tube 14 which is a throttle portion.
The expanded portion 62 continued from is formed as if concentric cylinders were superposed in stages. This allows the mixer 6
0 is easy to manufacture.

The gas-liquid dissolving / mixing apparatus of the present invention can be used not only for generating bubbles but also for dissolving gas in a liquid. Further, the narrowed portion may be formed by a Venturi tube or sharply narrowed into an orifice shape, and the shape thereof does not matter. Further, the shape of the nozzle portion and the number of nozzle openings can be appropriately set according to predetermined conditions.

[0025]

The gas-liquid dissolving and mixing method and the gas-liquid dissolving and mixing apparatus according to the present invention allow gas to flow in slightly downstream of the throttle portion provided in the liquid flow path and to the downstream of the widening portion continuing from the throttle portion. Since a gas and a liquid are mixed with each other and a gas-liquid mixed flow is ejected from a nozzle provided at an outlet, a small device can efficiently mix a large amount of gas into a liquid and generate bubbles. is there. Further, as compared with the case of using the conventional bubble column, a large amount of gas is dissolved in the liquid before it comes out of the nozzle portion, so that the time for dissolving the gas can be greatly shortened.

Further, in the gas-liquid dissolving and mixing apparatus of the present invention, the number and position of the nozzle portions can be freely set, the structure is simple and the manufacturing is easy, and the nozzle portion is separated from the mixer main body portion. With the shape, the position of the nozzle portion can be set more freely.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a mixer according to a first embodiment of a gas-liquid dissolution mixing device of the present invention.

FIG. 2 is a pipeline diagram of a gas-dissolved water producing apparatus using the gas-liquid dissolving and mixing apparatus of this embodiment.

FIG. 3 is a schematic front view of a mixer of a second embodiment of the gas-liquid dissolution mixing device of the present invention.

FIG. 4 is a partial vertical cross-sectional view of the mixer of the third embodiment of the gas-liquid dissolution mixing device of the present invention.

[Explanation of symbols]

 10 Mixer 12 Throat part 14 Venturi tube 16 Spread part 18 Gas inlet 20 Mixing part 22 Nozzle port 24 Nozzle part

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Masakazu Kashiwa, Inventor Masakazu Kashiwa 1-10-40 Mikuni Honcho, Yodogawa-ku, Osaka City, Izumi Electric Co., Ltd. (72) Takayuki Kinoshita 1 Mikuni-honcho, Yodogawa-ku, Osaka, Osaka 10-40 No. Izumi Electric Co., Ltd. (56) Reference Japanese Unexamined Patent Publication No. 2-280822 (JP, A) Actual Development Sho 49-122461 (JP, U) Actual Development Sho 55-130735 (JP, U)

Claims (5)

(57) [Claims] 1. A part of a liquid flow path is throttled, and the throttle part (1
2) The pipe is gradually expanded on the downstream side, and the gas is caused to flow slightly on the downstream side of the narrowed portion (12), and the gas and the liquid are pressurized on the downstream side of the expanded portion (16). A gas-liquid dissolving and mixing method, which comprises dissolving and mixing, jetting a gas-liquid mixed flow from a nozzle portion (24) provided at an outlet, and precipitating a gas dissolved in the liquid. 2. A throttle portion (12) provided in a liquid flow path.
And a widening portion (16) in which the pipe is gradually widened following the narrowing portion (12), and a gas inlet () provided in the widening portion (16) slightly downstream of the narrowing portion (12). 1
8), the liquid in the flow path provided downstream of the expanded portion (16) and the gas flowing in from the gas inlet (18).
At a pressure higher than the pressure of the gas at the gas inlet (18)
And a mixing section (20) for dissolving and mixing in
Nozzle part (2) that is provided at the outlet of the nozzle to eject a gas-liquid mixed flow to shear the bubbles and to precipitate the gas dissolved in the liquid
4) and the gas flowing in from the gas inlet (18)
The body pressure is not more than the static pressure at the outlet of the nozzle portion (24).
In case of the above, at the connection part of the gas inlet (18) above
From the cross-sectional area of the spread portion (16), the nozzle portion (24)
The sum of the cross-sectional areas of the nozzle opening (22) of
And set the flow rate from the gas inlet (18).
Depending on the pressure of the entering gas,
In order to reduce the static pressure of the liquid in the spread area
The gas-liquid dissolving and mixing apparatus is characterized in that the sum of the cross-sectional areas of the nozzle ports is set in the above . 3. A throttle portion (12) provided in a liquid flow path.
Then, the pipe line was gradually widened following this throttle (12).
The spreading part (16) and the slightly lower part of the throttle part (12)
Gas inlet (1) provided in the widening part (16) on the flow side
8) and in the flow path provided downstream of the widened portion (16)
And the gas flowing in from the gas inlet (18)
A mixing section (20) for dissolving and mixing under pressure, and this mixing section
A nozzle part (22) provided at the outlet of (20) is provided.
Well, according to the continuity equation in fluid mechanics and Bernoulli's theorem
The connection of the gas inlet (18) given by the following equation
At the widened part (16) in the sequelOf the above liquidStillness
Pressure P_AIs S_AAt the connection of the gas inlet (18)
The cross-sectional area of the widened portion (16), S_BIs the nozzle mouth (2
2) Sum of cross-sectional areas, P₁Of the gas inlet (18)
The total pressure, δP, of the expanded portion (16) at the connection site is
The spread at the connection of the gas inlet (18)
Pressure loss from the part (16) to the nozzle part (24),
P_BIs the static pressure at the outlet of the nozzle section (24), P_A= (1-S² _B/ S² _A) P₁+ (ΔP + P_B) S² _B/ S² _A And this P_AAnd from the gas inlet (18)
Gas pressure P_GAnd P_A<P_G  A gas-liquid dissolving and mixing device characterized by satisfying: 4. The gas-liquid dissolving / mixing device according to claim 2, wherein the nozzle portion (24) is provided with a plurality of nozzle openings (22). 5. The throttle section (12) and nozzle section (54)
The gas-liquid dissolving and mixing apparatus according to claim 2 or 3, characterized in that said and said are connected by a pipe line (56) which also serves as a mixing section (20).