JP2020015018A - Gas-liquid mixer - Google Patents

Abstract

To provide a gas-liquid mixer which can generate uniform fine air bubbles.SOLUTION: A gas-liquid mixer A having such a venturi structure that a diaphragm part 6 and a conical part 10 are provided on a main passage 5 through which a liquid passes includes a gas mixing path 9 for taking in gas from a tangential direction with respect to the main flow passage having a circular cross section, and a projection part 11 which is provided on the downstream side of the gas mixing path of an inner wall forming the main passage and extends in a central axis direction of the main passage. Preferably, the projection part is provided on the inner wall forming the conical part, and is formed so that the projection height from the inner wall is higher toward the downstream side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas-liquid mixing device, and more particularly, to a gas-liquid mixing device that generates fine bubbles.

  Fine bubbles can increase the amount of dissolved oxygen with high efficiency by increasing the gas-liquid interface, and have characteristics such as crushing phenomenon that decomposes chemical substances and generation of negative ions, culture, purification, washing, etc. And a venturi-structured gas-liquid mixing apparatus that generates uniform and fine bubbles are often used.

  As a gas-liquid mixing device with a Venturi structure that generates fine bubbles, a narrow portion of the main passage where the inside of the main passage is in a negative pressure state is formed by connecting a plurality of members, and a gas having a fine groove shape is formed on each joint surface. Provide an introduction point to mix fine gas and form a crushing groove downstream of the gas introduction part to increase the contact area between the gas and the flowing liquid, and crush bubbles by colliding with the water flow A technique for generating fine bubbles has been proposed (Patent Document 1).

  Further, a helical propeller-type cascade at the center of the main passage and a helical cascade around the main passage center opposite to the cascade of the main passage are provided downstream of the throttle portion of the gas-liquid mixed main passage. There has been proposed a technique in which a liquid flow in a liquid main passage is divided into two layers, swirled, and crushed to generate fine bubbles (Patent Document 2).

JP 2008-23513 A JP 2007-21343 A

  The amount of gas that can be mixed by the venturi structure is governed by the amount of change in the pressure of the main passage of the flowing liquid and the pressure of the throttle. Therefore, the amount of gas that can be mixed is determined by the pressure difference. Further, since a gas which is merely mixed does not become fine bubbles, various techniques for generating fine bubbles have been proposed.

  In Patent Literature 1, a plurality of stages of air introduction nozzles are connected to a nozzle member, and a small amount of gas to be sucked into a liquid flowing through a flowing water passage is mixed. A shallow groove for air suction is provided, and a groove for crushing bubbles connected to the groove for air suction is provided in the flow direction to increase the contact area between the gas and the flowing liquid, thereby colliding with the water flow. By doing so, fine bubbles are generated. However, the energy of the water flow sheared by the crushing groove is before the swirling flow is accelerated, and the amount of fine gas that can be sucked as fine bubbles at one joining surface where the groove is shallowly cut is limited. , It is necessary to provide a plurality of members, and the number of parts increases.

  Further, in Patent Document 2, by providing blade rows in different rotational directions in a cylindrical casing, liquid is suppressed and swirled by the blade rows. Therefore, the pressure loss of the pressurized liquid passing through the cascade increases, and the amount of air that can be mixed decreases. Fine air bubbles cannot be generated with a small flow rate, and the manufacture of a propeller-type cascade is complicated and expensive.

  An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a gas-liquid mixing device that can be manufactured at low cost and can generate uniform fine bubbles.

  In order to solve the above problem, the invention according to claim 1 is provided with a constricted portion and a conical portion connected to the downstream side of the constricted portion and having a diameter increasing toward the downstream side in the main passage through which the liquid passes. In the gas-liquid mixing device having a Venturi structure, a gas mixing path for taking in gas from the tangential direction to the main path having a circular cross section, and a gas mixing path provided on an inner wall forming the main path downstream of the gas mixing path. And a protruding portion extending in the central axis direction of the main passage.

  According to a second aspect of the present invention, in the first aspect of the invention, the projecting portion is provided on an inner wall forming the conical portion, and a protruding height from the inner wall increases toward the downstream side. The gist is that it is formed to be higher.

  According to a third aspect of the present invention, in the first or second aspect, the projecting portion is provided downstream of the conical portion of an inner wall forming the main passage. .

  According to a fourth aspect of the present invention, in the first aspect of the present invention, the main passage is formed over a first member and a second member joined to the first member. The gas mixing path is formed in a groove shape on the side of the joining surface of the first member to the second member, and at the joining surface of the first member and the second member, The gist is that the inner diameter of the main passage is larger than the inner diameter of the main passage of the first member on the upstream side.

  The gist of the invention described in claim 5 is that, in the invention described in any one of claims 1 to 4, a long hole-shaped discharge port is provided along the circumference of the central axis of the main passage. .

  According to the gas-liquid mixing device of the present invention, a gas mixing passage for taking in gas from a tangential direction to a main passage having a circular cross section, and a main passage provided downstream of the gas mixing passage of an inner wall forming the main passage. And a protruding portion extending in the central axis direction. Thus, in a component configuration based on the venturi structure, by mixing gas from the tangential direction to the main passage, the liquid flowing in the main passage can be made into a swirling flow in which gas-liquid is mixed. The main swirling flow in which the gas-liquid is mixed is accelerated by centrifugal force along the inner wall of the conical portion as it proceeds in the flow direction. The accelerated main swirling flow collides with the protruding portion to cause bubble crushing, and further generates a sub-swirling flow from the main swirling flow and collides with the main swirling flow to further violently break bubbles. As a result, uniform fine bubbles can be generated.

  Further, when the protruding portion is provided on the inner wall forming the conical portion, and is formed so that the protruding height from the inner wall increases toward the downstream side, the upstream side of the conical portion is provided. By setting the protruding portion low, the main swirling flow can be received downstream without resistance and accelerated effectively. Further, by setting the protruding portion high on the downstream side of the conical portion, bubble crushing due to collision is effectively performed.

  Further, when the protruding portion is provided downstream of the conical portion of the inner wall forming the main passage, the main swirling flow sufficiently accelerated by the conical portion collides with the protruding portion to generate bubbles. The crushing is performed effectively.

Further, the main passage is formed over a first member and a second member, the gas mixing passage is formed in a groove shape on a joint surface side of the first member, and the first member and the first member are formed in a groove shape. In the joining surface of the second member, when the inner diameter of the main passage of the second member is larger than the inner diameter of the main passage of the first member on the upstream side, the inner passage is larger than the main passage on the end surface of the first member. It is possible to form a gas mixing path connected to the tangent position of the maximum diameter of the circular main passage on the end face of the formed second member.
As described above, if the position of the mixed gas is the tangent position of the maximum diameter at which the gas swirls in the main passage, the energy of the swirl flow increases, and fine bubbles using the energy of the swirl flow can be uniformly generated.
Further, the gas can be mixed into a flow area where the liquid flowing through the main passage is difficult to flow when the liquid is released from the throttle section, and from the direction most suitable for the turning direction. For this reason, when being sucked into the liquid flowing through the main passage, it is possible to mix gas from a direction in which the liquid traveling direction and the tangential direction to the main passage are combined, and the gas is generated when mixed with the flowing liquid. Liquid energy loss can be reduced.

  Furthermore, in the case of providing a long hole-shaped discharge port along the circumference of the central axis of the main passage, the central flow, which is the flow around the central axis of the main passage that does not become a swirling flow, flows along the inner wall of the conical portion. By colliding with the accelerated swirling flow, finer and uniform gas bubbles of fine bubbles can be discharged from the discharge port.

The invention will be further described in the following detailed description, given by way of non-limiting example of an exemplary embodiment according to the invention and with reference to the referenced figures, wherein like reference numerals are used to refer to the figures. Similar parts are shown throughout the several figures.
It is a longitudinal section of the gas-liquid mixing device concerning an example. FIG. 2 is an enlarged cross-sectional view taken along line II-II of FIG. 1. FIG. 3 is an enlarged cross-sectional view taken along line III-III of FIG. 1. It is a principal part enlarged view of FIG. It is a longitudinal section of the 2nd member which constitutes the above-mentioned gas-liquid mixing device. FIG. 6 is an enlarged cross-sectional view taken along line VI-VI of FIG. 1. It is an explanatory view for explaining a projection part concerning other forms. It is explanatory drawing for demonstrating the protrusion part which concerns on another another form. FIG. 2 is an enlarged view taken along arrow IX in FIG. 1. It is the perspective view which fractured | ruptured a part of the downstream end side of the said gas-liquid mixing apparatus. It is explanatory drawing for demonstrating the gas-liquid mixing apparatus of another form, (a) shows the longitudinal section of a gas-liquid mixing apparatus, (b) shows the bb line cross section.

  The matters shown here are for the purpose of exemplifying the exemplary embodiments and the embodiments of the present invention, and should be described so that the principles and conceptual features of the present invention can be most effectively and easily understood. It is intended to provide what seems to be possible. In this respect, it is not intended to show the structural details of the invention beyond that which is necessary for a fundamental understanding of the invention, and that some forms of the invention will be It will be clear to those skilled in the art how it is actually embodied.

  In the gas-liquid mixing device according to the present embodiment, the main passage (5) through which the liquid passes includes a constricted portion (6) and a conical portion (10) connected to the downstream side of the constricted portion and increasing in diameter toward the downstream side. In a gas-liquid mixing device (A) having a venturi structure provided with a gas, a gas mixing passage (9) for taking in gas from a tangential direction to a main passage (5) having a circular cross section, and an inner wall forming the main passage (5) A protruding portion (11) provided downstream of the gas mixing passage (9) and extending in the direction of the central axis of the main passage (5) (see, for example, FIGS. 1 and 11). Thereby, the swirling flow (6a) is generated in the liquid flowing through the main passage (5) by the mixed gas (9a) mixed from the gas mixing path (9) (for example, see FIG. 2 and the like). As the swirling flow (6a) advances in the flow direction, a main swirling flow (10a) accelerated by centrifugal force along the inner wall of the conical portion (10) and a sub-swirl by providing a protruding portion (11). A flow (11a) is generated (see, for example, FIG. 6).

  The shape, size, location, number and the like of the gas mixing path (9) are appropriately selected according to the flow rate of the liquid and the like. The shape, size, location, number, and the like of the protrusions (11) are appropriately selected according to the flow rate of the liquid and the like.

  In the gas-liquid mixing device according to the present embodiment, the protruding portion (11) is provided on the inner wall forming the conical portion (10), and the protruding height from the inner wall increases toward the downstream side. (See, for example, FIGS. 5 and 7).

  In the case of the above embodiment, for example, the protruding portion (11) is formed so that the protruding height from the inner wall of the conical portion (10) gradually increases toward the downstream side in the longitudinal direction. (See, for example, FIG. 5). Further, for example, the protruding portion (11) includes a gradually changing portion (18a) in which the protruding height of the conical portion (10) from the inner wall gradually increases toward the downstream side, and a gradually changing portion (18a). ) And a constant height portion (18b) having the same protruding height on the downstream side (see, for example, FIG. 7).

  In the gas-liquid mixing device according to the present embodiment, for example, the projection (11) is provided downstream of the conical portion (10) of the inner wall forming the main passage (5) (for example, 11 and the like).

  In the gas-liquid mixing device according to the present embodiment, for example, the main passage (5) is formed over a first member (1) and a second member (2) joined to the first member (1). In addition, the gas mixing path (9) is formed in a groove shape on the joint surface side of the first member (1) with the second member (2), and is formed by the first member (1) and the second member (2). In the joining surface, the inner diameter of the main passage (5) of the second member (2) is larger than the inner diameter of the main passage (5) of the first member (1) on the upstream side (for example, see FIG. 4 and the like). Is mentioned. Thereby, the gas from the gas mixing passage (9) can be mixed into the tangential position of the main passage (5) of the second member (2), and can also proceed in the liquid flow direction.

  As the gas-liquid mixing device according to the present embodiment, for example, a form including a long hole-shaped discharge port (14) along the circumference of the central axis of the main passage (5) (for example, FIGS. 9 and 10 and the like) Reference). Thus, the flow (13a) around the central axis of the main passage (5) that does not become a swirl flow can collide with the accelerated swirl flow (10a). The size, number, location, and the like of the discharge ports (14) are appropriately selected according to the discharge amount and the like.

  It should be noted that reference numerals in parentheses of each configuration described in the above-described embodiment indicate a correspondence relationship with a specific configuration described in Examples described later.

  Hereinafter, the present invention will be described specifically with reference to the drawings.

  As shown in FIG. 1, the gas-liquid mixing device A according to the present embodiment includes a main body 16 in which a main passage 5 through which a liquid passes is formed. The main body 16 includes a first member 1, a second member 2, and a third member 3 connected by the same shaft. Each of the first to third members 1 to 3 is formed in a cylindrical shape from a material such as metal or resin. The first member 1 is joined to one shaft end side of the second member 2 by screwing or the like. Further, the third member 3 is joined to the other shaft end side of the second member 2 by screwing or the like. Further, the main passage 5 is provided with a constricted portion 6 and a conical portion 10 which is connected to the downstream side of the constricted portion 6 and whose diameter increases toward the downstream side. Therefore, the gas-liquid mixing device A has a venturi structure.

  The first member 1 is provided with a main passage inlet 4 and a throttle portion 6 connected to the downstream side of the main passage inlet 4. Further, the first member 1 has a gas inlet 7, a gas suction chamber 8, and a gas mixing passage 9 for mixing gas into the main passage 5 (specifically, a connection portion between the throttle portion 6 and the conical portion 10). Are formed. The gas mixing passage 9 is connected in a tangential direction on the circumference of the central axis of the main passage 5 so as to mix gas from the main passage 5 in a tangential direction.

  In the first member 1, the cross-sectional area of the throttle portion 6 is formed smaller than the cross-sectional area of the main passage inlet 4. The liquid flowing from the main passage inlet 4 passes through the throttle unit 6. At this time, due to the venturi structure, the liquid inside the throttle unit 6 flows at a high speed and is in a negative pressure state. A gas mixing passage 9 is formed downstream of the throttle section 6 in the negative pressure state. When the gas mixing passage 9 passes through the gas mixing passage 9 in the negative pressure state, the gas passing through the gas suction chamber 8 connected to the outside air is formed. Is mixed from the gas mixing path 9.

  Here, as shown in FIG. 2, by mixing the mixed gas 9 a through a gas mixing passage 9 formed tangentially to the central axis of the main passage 5, the rectifying liquid is mixed in the central axis direction of the main passage 5. Accordingly, the swirling flow 6a of the central axis of the main passage 5 in which the gas and the liquid are mixed can be obtained. The gas is sheared by this swirling, but at this stage, bubbles having a large particle size remain and are not uniform.

  Further, by forming the gas suction chamber 8 on the outer ring of the main passage 5, the gas mixing passage 9 formed tangentially to the central axis of the main passage 5 can be connected to the main passage 5 from any direction. The gas inlet 7 connecting the gas suction chamber 8 and the outside air can be formed at one place.

  As shown in FIG. 3 and FIG. 4, the gas mixing passage 9 is formed in a groove shape on the joining surface of the first member 1 to the second member 2, and the main passage 5 on the end surface of the second member 2 is formed on the end surface of the first member 1 Is formed to be larger than the main passage 5 so that the gas mixing passage 9 provided tangentially to the central axis of the main passage 5 is connected to the tangent position of the maximum diameter of the circular main passage 5 on the end face of the second member 2. can do. Further, the connection end side of the gas mixing path 9 with respect to the throttle section 6 is open to the conical section 10.

  When the liquid flowing through the main passage 5 passes through the joint surface between the first member 1 and the second member 2, the liquid changes from a cross section of the constricted portion 6 to a cross section upstream of the conical portion 10 that is larger than the cross section of the constricted portion 6. At this time, in the inside of the main passage 5, a basin R in which the liquid does not easily flow is formed around the circumference of the end surface of the conical portion 10, that is, in the vicinity of the tangential portion connecting the gas mixing passage 9 on the end surface of the second member 2 ( (See FIG. 4). By allowing the gas to flow into the basin R, the gas can be mixed with the liquid along the flow of the liquid flowing through the main passage 5.

  In this way, gas can be mixed from the direction in which the tangential direction with respect to the central axis of the main passage 5 and the direction along the flow of the liquid flowing through the main passage 5 are mixed, and the rectifying liquid is The swirling flow 6a of the central axis of the main passage 5 in which gas-liquid mixing is efficiently performed can be obtained.

  Further, by forming the gas mixing passage 9 in a groove shape on the joint surface of the first member 1, processing from the liquid flow axis direction at the time of manufacturing the member becomes possible. Therefore, the annular gas suction chamber 8 formed outside the main passage 5 and the gas mixing passage 9 can be manufactured by an integral member, so that the cost is reduced.

  As shown in FIGS. 5 and 6, the second member 2 is formed with a conical portion 10 and a plurality (four in FIG. 6) of protruding portions 11 protruding from the inner wall forming the conical portion 10. ing. In the second member 2, the conical portion 10 is formed at a conical angle 101 with respect to the central axis of the main passage 5 so that the cross section of the main passage 5 becomes larger as it proceeds in the flow direction. Therefore, the gas-liquid mixed swirling flow 6a from the constricted portion 8 is accelerated by centrifugal force as the flow proceeds along the inner wall of the conical portion 10 into the swirling flow 10a (see FIG. 6). In this embodiment, a conical portion 10 and a protruding portion 11 formed by wire electric discharge machining are exemplified.

  The plurality of protrusions 11 are formed in a plate shape extending in the central axis direction of the main passage 5. Each of the projecting portions 11 extends over substantially the entire length of the conical portion 10 in the longitudinal section along the central axis of the main passage 5 of the second member 2. Further, the inclination angle of the protruding end edge of each projection 11 with respect to the central axis of the main passage 5 is smaller than the inclination angle of the inner wall of the conical portion 10 with respect to the central axis of the main passage 5. In addition, each protruding portion 11 is formed such that the protruding height from the inner wall of the conical portion 10 gradually increases in the longitudinal direction toward the downstream side.

  The plurality of protrusions 11 are arranged at equal pitch angular intervals around the central axis of the conical part 10. The angle 102 formed by the protruding edges of the pair of opposing protrusions 11 among the plurality of protrusions 11 is smaller than the cone angle 101 formed by the cone 10. Since the protruding portion 11 is low at the upstream portion of the conical portion 10 before acceleration, the main swirling flow 6a is received downstream without resistance and accelerated, and the protruding portion is formed at the downstream portion of the conical portion 10 of the further accelerated swirling flow 10a. Since the portion 11 is high, the bubble crushing due to a violent collision and the secondary swirling flow 11a are generated, and the bubble crushing is performed more violently by colliding with the main swirling flow 10a.

  Here, in the present embodiment, the protruding portion 11 in which the protruding height of the conical portion 10 from the inner wall gradually increases toward the downstream side is illustrated, but the present invention is not limited to this. For example, FIG. As shown, the protruding portion 11 has a gradually changing portion 18a in which the protruding height from the inner wall of the conical portion 10 gradually increases toward the downstream side, and a protruding height connected to the downstream side of the gradually changing portion 18a. And the same constant height portion 18b. In this case, the starting point (upstream end) of the constant height portion 18b is different from the starting point (upstream end) of the inner wall of the conical portion 10. Note that the angle and the starting point for forming the projecting portion 11 and the number of projecting portions can be set according to the liquid flow rate and the air amount.

  Further, in the present embodiment, since the projection 11 has a corner on the protruding end side, gas bubbles passing through the corner can generate fine bubbles by cavitation. However, for example, as shown in FIG. 8, the protruding portion 11 may have an arc shape having no corner on the protruding end side. In this case, the collision sound between the protruding portion 11 and the swirling flow 10a is suppressed.

  The third member 3 is formed in a bottomed cylindrical shape as shown in FIGS. 9 and 10. The third member 3 forms a discharge chamber 13 with the second member 2. On the bottom surface side of the third member 3, a long hole-shaped discharge port 14 is formed along the circumference of the central axis of the main passage 5. The plurality of discharge ports 14 (three in FIG. 9) are arranged around the center axis of the main passage 5 at equal pitch angular intervals. In this way, by providing the discharge port 14 in the shape of a long hole along the circumference of the central axis of the main path 5 without providing the discharge port on the center side of the main path 5, the main path 5 that does not become the swirling flow 10a is provided. The central flow 13a, which is a flow around the central axis of the nozzle, collides with the main swirl flow 10a accelerated along the inner wall of the conical portion 10 in the discharge chamber 13, thereby discharging more uniform gas and liquid of fine bubbles. Can be discharged.

Next, a gas-liquid mixing test according to an experimental example and a comparative example will be described.
In the gas-liquid mixing test of the experimental example, the gas-liquid mixing device A according to the example was adopted, and the discharge flow discharged from the discharge port 14 was observed. On the other hand, in the gas-liquid mixing test of the comparative example, the gas-liquid mixing device A according to the example without the projection 11 was employed, and the discharge flow discharged from the discharge port 14 was observed. As a result, in the gas-liquid mixing test of the experimental example, it was confirmed that the discharge flow contained uniform fine bubbles of 0.1 mm or less. On the other hand, in the gas-liquid mixing test of the comparative example, it was confirmed that in addition to fine bubbles of 0.1 mm or less, bubbles of about 1 mm were included in the discharge flow.

  It should be noted that the present invention is not limited to the above-described embodiment, but may be variously modified within the scope of the present invention according to the purpose and application. That is, in the above-described embodiment, the form in which the protruding portion 11 is raised on the inner wall of the conical portion 10 is exemplified. However, the present invention is not limited to this. For example, as shown in FIG. The protruding portion 11 may be provided on the downstream side of the portion 10 (specifically, on the inner wall forming the discharge chamber 13). In this case, for example, the protrusion 11 may be provided on the inner wall of the main passage 5 over the conical portion 10 and the downstream side of the conical portion 10.

  Further, in the above-described embodiment, the protruding portion 11 having the linear protruding end edge in which the protruding height of the conical portion 10 from the inner wall increases toward the downstream side is exemplified, but is not limited thereto. The protruding portion 11 may have a stepped or curved protruding edge in which the protruding height of the conical portion 10 from the inner wall increases toward the downstream side. Further, for example, the protrusion 11 may have a constant height from the inner wall of the conical portion 10.

  Further, in the above-described embodiment, the protruding portion 11 extending over the entire length of the inner wall of the conical portion 10 in the longitudinal section along the central axis of the main passage 5 is illustrated, but is not limited thereto. May be a protruding portion 11 extending along a part of the entire length of the inner wall of the conical portion 10 in a vertical cross section along the line.

  The gas-liquid mixing device of the present invention is not limited to the configuration of the above-described embodiment, and the configuration may be changed as appropriate without departing from the essence of the claimed invention.

  INDUSTRIAL APPLICABILITY The present invention is widely used as a technique relating to gas-liquid mixing used in various fields such as aquaculture, purification, and washing.

  1; first member, 2; second member, 3; third member, 4; main passage inlet, 5; main passage, 6; throttle section, 6a; swirling flow, 7; gas inlet, 8; 9; gas mixing path, 9a; mixed gas, 10; conical portion, 10a; main swirling flow, 11; projecting portion, 11a; sub-swirl flow, 13; discharge chamber, 13a; center flow, 14; Body; 101; cone angle; 102; angle;

Claims (5)

In a gas-liquid mixing device having a venturi structure, a main passage through which a liquid passes is provided with a constricted portion and a conical portion connected to the downstream side of the constricted portion and increasing in diameter toward the downstream side.
A gas mixing path for taking in gas from the tangential direction to the main passage having a circular cross section,
A gas-liquid mixing device, comprising: a protruding portion provided on an inner wall of the main passage downstream of the gas mixing passage and extending in a central axis direction of the main passage.   The gas-liquid mixing device according to claim 1, wherein the protruding portion is provided on an inner wall forming the conical portion, and is formed such that a protruding height from the inner wall increases toward a downstream side.   3. The gas-liquid mixing device according to claim 1, wherein the protruding portion is provided downstream of the conical portion of an inner wall forming the main passage. 4. The main passage is formed over a first member and a second member joined to the first member,
The gas mixing path is formed in a groove shape on the joining surface side of the first member to the second member,
4. The joint surface between the first member and the second member, wherein the inner diameter of the main passage of the second member is larger than the inner diameter of the main passage of the first member on the upstream side. The gas-liquid mixing device according to claim 1.   5. The gas-liquid mixing device according to claim 1, further comprising a discharge port having a long hole shape along a circumference of a center axis of the main passage. 6.

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