JP2010082533A - Mixer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact mixer allowing uniform mixing with no unevenness in concentration distribution and temperature distribution in the fluid flow direction, and easy in piping work. <P>SOLUTION: The mixer includes a fluid inlet, a first flow path communicated with the fluid inlet, a liquid chamber communicated with the first flow path, a plurality of branch flow paths communicated with the liquid chamber via respective first communication holes, a joint part where the branch flow paths joint, a second flow path communicated with the joint part, and a fluid outlet communicated with the second flow path. The plurality of the branch flow paths are formed with different inner diameters from each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mixer used for fluid transportation piping in various industries such as chemical factories, semiconductor manufacturing fields, food fields, medical fields, and bio fields, and in particular, uneven concentration distribution and temperature distribution in the fluid flow direction. The present invention relates to a mixer that can be uniformly mixed without mixing.

  Conventionally, as a method for uniformly mixing a fluid flowing in a pipe after being mounted in a pipe, a method using a twisted blade-shaped static mixer element 81 as shown in FIG. 8 has been generally used (for example, Patent Document 1). reference). Usually, the static mixer element 81 has a rectangular plate twisted 180 degrees around its longitudinal axis as a minimum unit member, and a plurality of minimum unit members are integrally connected in series so that twist directions are alternately different. It has a combined structure. The static mixer element 81 is disposed in the pipe 82, the mail connector 83 is attached to both ends of the pipe 82, the flare 85 is attached, and the fastening nut 84 is fastened to form a static mixer. At this time, the outer diameter of the static mixer element 81 is designed to be substantially equal to the inner diameter of the pipe 82 so that the fluid is effectively stirred.

  However, since the fluid mixing method using the conventional static mixer is configured to stir the flowing fluid along the flow, the concentration distribution in the radial direction of the pipe is uniform as shown in FIG. Although it can be made uniform, the concentration distribution in the axial direction (flow direction) cannot be made uniform as shown in FIG. 9B. For this reason, for example, when water and chemicals are mixed and flowed upstream of the static mixer, if the mixing ratio of the chemicals temporarily increases, it passes through the static mixer with the concentration partially increased in the flow path. To do. At this time, even if the water and the chemical solution were homogenized in the radial direction and the water and the chemical solution were stirred, the portion where the concentration was partially increased in the flow path in the axial direction (flow direction) became almost undiluted. It flows to the downstream side in the state (see FIG. 9B). As a result, when connected to a semiconductor cleaning device, especially a device that directly applies chemicals to the surface of a semiconductor wafer and performs various treatments, chemicals with different concentrations are applied to the surface of the semiconductor wafer, causing a defective product. There was a problem.

  As a method of avoiding this uneven concentration distribution in the axial direction (flow direction), a tank is installed in the middle of the flow path, the fluid is temporarily stored in the tank, and the concentration in the tank is made uniform. The method of flowing (not shown) etc. are mentioned. However, the installation of the tank requires a large space and the equipment becomes large, and the transport of the fluid from the tank again requires a pump, piping, etc. There was a problem that the cost for constructing the piping line occurred. In this method, fluid stays in the tank. When the fluid stays, bacteria are generated, and the bacteria generated in the tank flow into the piping line, and in the semiconductor manufacturing line, there is a problem that adheres to the semiconductor wafer and causes defective products.

  As another method for avoiding unevenness in the concentration distribution in the axial direction (flow direction), there is a branch dilution apparatus that dilutes a fluid by branching a flow path as shown in FIG. 10 (see, for example, Patent Document 2). ). This apparatus is an apparatus for analyzing a sample solution flowing through a narrow tube 91 at a constant speed, and a sample solution is provided by providing a branch portion 92 for branching the flowing sample into a plurality of channels in the middle of the channel. , The inner diameters and lengths of the narrow tubes 93 and 94 of each branch flow path are changed, and merged again at the merge section 96 in front of the detector 95, and diluted using the time difference at which the sample solution is detected. Met.

JP 2001-205062 A JP-A-8-146008

  However, when the technique of the conventional branch dilution apparatus shown in FIG. 10 is used for the fluid transportation pipe, it is necessary to provide a pipe line that is provided in the middle of the pipe and has a different length and is joined again. For this reason, in order to make the concentration distribution in the axial direction (flow direction) uniform in the flow path without unevenness, it is necessary to provide many branched flow paths, and in that case, a large space is required for providing branched piping lines. There was a problem of becoming. Moreover, in order to construct such a piping line, there is a problem that a large number of parts are required, which is complicated and takes time.

  The object of the present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to mix the concentration distribution and temperature distribution in the flow direction of the fluid uniformly and evenly, and it is compact and easy to install piping. Is to provide a vessel.

  The structure of the present invention for solving the above-described problem will be described. The mixer includes a fluid inlet, a first flow path communicating with the fluid inlet, a liquid chamber communicating with the first flow path, and a liquid chamber connected to the liquid chamber. A plurality of branch flow paths communicating with each other through each of the series of through holes, a merge section where the branch flow paths merge, a second flow path communicating with the merge section, and a second flow path communicating with the second flow path The first feature is that the plurality of branch channels have different inner diameters.

  A concave portion is provided on one side surface, and a plurality of bottomed cylindrical branch channels having different inner diameters are provided on the other side surface, and the first series of holes communicating the bottom surface of the recess and the bottom surface of the branch channel are respectively provided. A first channel that has a main body portion, a first flow channel, and a tapered portion that gradually decreases in diameter from one side surface toward the inner peripheral surface of the first flow channel, and the tapered portion forms a liquid chamber together with the concave portion of the main body portion. A joint portion, a second flow path, and a joining portion having a tapered portion that gradually decreases in diameter from one side surface toward the inner peripheral surface of the second flow channel, and the tapered portion communicates with the branch flow channel of the main body portion The second feature is that a second joint portion is formed.

  A third feature is that the apparatus further comprises an intermediate joint portion that is interposed between the main body portion and the second joint portion and has second communication holes that respectively communicate with the junction portion from the branch flow path.

  A fourth feature is that the first communication hole or the second communication hole is provided at a position eccentric with respect to a central axis of each of the branch flow paths.

  The diameter of each of the main body portion and the second joint hole of each of the intermediate joint portions is gradually increased from the communication hole toward the inner peripheral surface of the branch flow path. A fifth feature is that a tapered portion is provided.

  The sixth feature is that the opening areas of the first series of through holes are formed substantially the same.

  The material of each part such as the main body portion 1, the first joint portion 5, the second joint portion 11 and the intermediate joint portion 26 of the mixer of the present invention may be any of polyvinyl chloride, polypropylene, polyethylene, etc. as long as it is made of resin. . Particularly when a corrosive fluid is used as the fluid, it is preferably a fluororesin such as polytetrafluoroethylene (hereinafter referred to as PTFE), polyvinylidene fluoride, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin, If it is made of resin, it can be used for a corrosive fluid, and even if a corrosive gas permeates, there is no need to worry about corrosion of the piping member, which is preferable.

The present invention has the structure as described above, and the following excellent effects can be obtained.
(1) Even when the concentration of the chemical solution is temporarily increased or decreased in the flow path, the concentration distribution in the flow direction of the fluid can be uniformly and evenly mixed, and the chemical solution with a stable concentration can be supplied. Yes, it is possible to prevent the occurrence of defects due to changes in chemical concentration in various fields.
(2) Even when the temperature of the fluid temporarily rises or falls within the flow path, the temperature distribution in the fluid flow direction can be evenly and evenly mixed, and fluid with a stable temperature can be supplied. Yes, it can stabilize the temperature in a water heater or the like and prevent burns.
(3) The mixer can be miniaturized and its installation space can be minimized.
(4) Pipe construction is easy and can be done in a short time.

  Hereinafter, embodiments of the present invention will be described with reference to examples shown in the drawings. However, it is needless to say that the present invention is not limited to the examples. FIG. 1 is a schematic diagram of a piping channel showing a mixer according to a first embodiment of the present invention. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a schematic diagram showing an apparatus for measuring the concentration of fluid using the mixer of FIG. FIG. 4 is a graph obtained by measuring the concentration on the upstream side of the mixer of FIG. FIG. 5 is a graph obtained by measuring the concentration on the downstream side of the mixer of FIG. FIG. 6 is a longitudinal sectional view showing a mixer according to the second embodiment of the present invention. FIG. 7 is a longitudinal sectional view showing another variation of the second communication hole of the second embodiment.

  Hereinafter, with reference to FIG. 1 and FIG. 2, the mixer which is 1st embodiment of this invention is demonstrated.

  The main body 1 is made of PTFE and has a cylindrical shape. A concave portion 2 is provided on one side surface of the main body 1, and ten bottomed cylindrical branch channels 3 having different inner diameters are provided on the other side surface so that the axes are parallel to each other. From FIG. 2, the inner diameters of the branch channels 3 a to 3 j are formed so as to increase stepwise from the branch channel 3 a having the smallest inner diameter at a substantially constant ratio. The inner diameter is 3a <3b <3c <3d <3e <3f <3g <3h <3i <3j. The main body 1 is also provided with first through holes 4a to 4j that respectively connect the bottom surface of the recess 2 and the bottom surfaces of the branch channels 3a to 3j. The inner diameters of the first through holes 4a to 4j are the same.

  The first joint portion 5 is made of PTFE, and is provided with a fluid inlet 6 on one side, and gradually contracts toward the inner peripheral surface of the first channel 7 on the other side and the first channel 7 communicating with the fluid inlet 6. A taper portion 8 having a diameter is provided. A female screw portion 9 is provided at the inner peripheral surface end of the first joint portion 5 on the side having the taper portion 8, and is screwed and fixed to the outer peripheral surface of the main body portion 1. A liquid chamber 10 is formed by the tapered portion 8 and the concave portion 2 of the main body portion 1.

  The second joint portion 11 is made of PTFE, and is provided with a fluid outlet 12 on one side surface, a second flow path 13 communicating with the fluid outlet 12, and the other side face toward the inner peripheral surface of the second flow path 13. A tapered portion 14 that gradually decreases in diameter is provided. A female threaded portion 15 is provided at an end portion of the inner peripheral surface of the second joint portion 11 on the side having the tapered portion 14, and is screwed and fixed to the outer peripheral surface of the main body portion 1. The inner periphery of the taper portion 14 and the other side surface of the main body portion 1 form a merging portion 16 of the fluid flowing in from the branch flow paths 3a to 3j of the main body portion 1.

  Next, the operation of the mixer according to the first embodiment of the present invention will be described.

  When water and a chemical solution are mixed on the upstream side of the mixer and flowed in a state where the concentration of the chemical solution is temporarily high, the chemical solution that is partially concentrated in the flow path is flown into the fluid inlet 6. Then, it flows into the first flow path 7 and flows into the liquid chamber 10. And the part of the chemical | medical solution with which the density | concentration became deep is branched by the ten 1st through-holes 4a-4j connected to the liquid chamber 10 from the liquid chamber 10, and flows into each branch flow path 3a-3j. The portion of the concentrated chemical solution that has flowed into the branch flow path 3a through the first through-hole 4a flows into the branch flow path 3a, fills it, and then flows through the junction 16 after being filled. It flows to the outlet 12. Next, the portion of the concentrated chemical solution that has flowed into the branch flow path 3b through the first through-hole 4b flows into the branch flow path 3b, fills it, and then flows through the junction 16 Flows through to the fluid outlet 12. At this time, since the inner diameter of the branch flow path 3b is set to be slightly larger than the inner diameter of the branch flow path 3a, the portion of the drug solution having a high concentration has a time difference to fill each branch flow path 3a, 3b. And a portion of the chemical liquid having a high concentration from the branch flow path 3b flows to the fluid outlet 12 through the merging portion 16 with a slight delay from the branch flow path 3a. Next, the portion of the concentrated chemical solution that has flowed into the branch flow path 3c through the first through-hole 4c flows into the branch flow path 3c, fills it, and then flows through the junction 16 Flows through to the fluid outlet 12. At this time, since the inner diameter of the branch flow path 3c is set to be slightly larger than the inner diameter of the branch flow path 3b, the portion of the chemical solution having a high concentration has a time difference to fill each branch flow path 3b, 3c. And a portion of the chemical liquid having a high concentration from the branch flow path 3c flows through the junction 16 to the fluid outlet 12 with a slight delay from the branch flow path 3b. Thereafter, as in 3a, 3b, and 3c, the remaining portion of the chemical solution having a high concentration flows through 3d to 3j and then flows to the fluid outlet 12 through the second flow path 13.

  At this time, a part of the chemical liquid having a high concentration flowing through the branch flow path 3a flows out from the fluid outlet 12 earlier than the chemical liquid having a high concentration flowing through the other branch flow paths, and the branch flow path 3b, A part of the chemical solution whose concentration is increased in order of the branch channel 3c and the branch channels 3d to 3j flows out from the fluid outlet 12. In other words, the chemical liquid that is partially concentrated in the flow path flows in 10 portions by the time difference by the mixer, and flows by being mixed with the chemical liquid that is not concentrated in concentration. The density distribution in the direction can be evenly mixed without any unevenness. At this time, if the inner diameter of each of the first through holes 4a to 4j is substantially the same, the portion of the concentrated chemical solution is divided into approximately 10 equal parts, so that the concentration distribution in the fluid flow direction is more uniform. Can be homogenized and mixed.

  In the present embodiment of FIG. 1, the branch flow paths 3a to 3j are provided so that the inner diameter gradually increases at a constant ratio. However, the branch flow paths 3a to 3j are applied to the fluid flowing through the branch flow paths 3a to 3j. The ratio of the inner diameter may be set freely to adjust the time difference. Further, the number of branch flow paths 3a to 3j is not particularly limited. If the number of the branch flow paths 3a to 3j is increased, the concentration distribution in the fluid flow direction can be made more uniform and uniform.

  Further, the mixer of the present embodiment is relatively easy to process for the complexity of the flow path, and can be easily manufactured and assembled with a small number of parts. Moreover, since the flow channel structure is small, the mixer can be miniaturized and can be installed without taking up piping space. If each of the branch flow paths 3a to 3j of the main body 1 is provided so that the inner diameter is increased stepwise, that is, the volume of each of the branch flow paths 3a to 3j is increased stepwise, The space between the mixers can be freely changed as desired, and the shape of the mixer can be changed in accordance with the situation of the equipment to be installed. In addition, when the mixer is connected to the piping line, the construction is completed simply by connecting the fluid inlet 6 and the fluid outlet 12 with a joint or the like, so that the piping construction is easy and can be performed in a short time.

  Here, the operation of dividing the concentration of the chemical solution having a high concentration by the mixer and uniformizing the concentration distribution in the fluid flow direction without unevenness will be described. As shown in FIG. 3, concentration meters 100 and 101 are installed on the upstream side and the downstream side of the mixer 102 in FIG. 1 to create a device for mixing and flowing pure water and chemicals from the upstream side. The concentration of the chemical solution is increased instantaneously (while increasing the ratio of the chemical solution with respect to pure water) in the middle of flowing the chemical solution at a constant ratio, and then the concentration distribution by flowing at the original constant ratio. 4 and 5 are measured when the concentrations on the upstream side and the downstream side when the unevenness is generated are measured.

  FIG. 4 shows a graph of the densitometer 100 installed on the upstream side of the mixer. Here, the horizontal axis is the elapsed time, the vertical axis is the concentration, and in the case where the concentration increases at a certain time, Such a peak (h1) will appear. FIG. 5 shows a graph of the densitometer 101 installed on the downstream side of the mixer. The concentration peak is dispersed into ten, and the height of the peak (h2) is about 1/10. The interval t1 between the concentration peaks corresponds to the time difference between the time when the fluid flows through the branch flow path 3a and the time when the fluid flows through the branch flow path 3b. Similarly, t2 The time difference between the times flowing through the channel 3c, t3 is the time difference between the times flowing through the branch channel 3c and the branch channel 3d, t4 is the time difference between the times flowing through the branch channel 3d and the branch channel 3e, and t5 is branched from the branch channel 3e. The time difference of the time flowing through the flow path 3f, t6 is the time difference of the time flowing through the branch flow path 3f and the branch flow path 3g, t7 is the time difference between the time flowing through the branch flow path 3g and the branch flow path 3h, and t8 is the flow path where the fluid is branched. 3h corresponds to the time difference between the time for flowing through the branch channel 3i, and t9 corresponds to the time difference between the time for the fluid to flow through the branch channel 3i and the branch channel 3j. At this time, the intervals t1 to t9 at which the peak (h2) appears can be changed by changing the inner diameter of each of the branch channels 3a to 3j, and the peak (h2) when the number of the branch channels 3a to 3j is further increased. ) Can be suppressed to a height that is divided by the number of branch channels with respect to the upstream peak (h1). If the mixer is not installed, the concentration peak shown in FIG. 5 may slightly decrease depending on the fluid flow, but the peak (h1) flows almost unchanged.

  In the present embodiment, the unevenness of the concentration distribution is described. However, the same effect can be obtained for the uniform flow direction of the temperature distribution when hot water and cold water are mixed. For the purpose of uniforming the temperature distribution, it can also be used in hot water heaters, etc., and by making the flow direction of the fluid partially heated in the flow path uniform, the temperature becomes more stable, It is possible to prevent burns caused by flowing. In the case of waste liquid treatment, etc., if there is a trouble in treatment if there is a sudden change in concentration, or if a problem occurs if the concentration exceeds a certain level, the spiral fluid mixer of the present invention is applied to this piping line. By using it, the concentration in the flow direction can be made uniform, and a stable drainage treatment can be performed. Also, the flowing fluid may be a gas.For example, in the purification of automobile exhaust gas, if the exhaust gas concentration suddenly increases when the engine starts or accelerates, the load of the catalyst for purification becomes large and the purification capacity decreases. Though conceivable, by using the spiral fluid mixer of the present invention in the exhaust gas piping line, the concentration in the flow direction can be made uniform, and stable exhaust gas purification can always be performed.

  Next, the mixer which is 2nd embodiment of this invention is demonstrated with reference to FIG. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals.

  The main body 21 is made of PTFE and is formed in a columnar shape. A concave portion 22 is provided on one side surface of the main body 21, and ten bottomed cylindrical branch channels 23 having different inner diameters are provided on the other side surface so that the axes are parallel to each other. The inner diameter of the branch channel 23 is formed to increase stepwise from the branch channel having the smallest inner diameter at a substantially constant rate. The main body 21 is provided with a first series of through holes 24 for communicating the bottom surface of the recess 22 and the bottom surface of the branch channel 23. Further, a tapered portion 25 having a diameter gradually increased from the first series of through holes 24 toward the inner peripheral surface of the branch channel 23 is provided on the inner periphery of the branch channel 23.

  The intermediate joint portion 26 is made of PTFE, and is provided with second communication holes 27 that communicate with the branch flow paths 23 of the main body portion 21, respectively, from the second communication holes 27 toward the inner peripheral surface of each branch flow path 23. A tapered portion 28 having a gradually increased diameter is provided. The intermediate joint part 26 is sandwiched and fixed between the main body part 21 and the second joint part 11, and the second communication hole 27 is connected from the branch flow path 23 between the intermediate joint part 26 and the tapered part 14 of the second joint part 11. A merging portion 16 of the fluid flowing in through is formed. Since the other structure of 2nd Embodiment is the same as that of 1st Embodiment, description is abbreviate | omitted.

  Next, the operation of the mixer according to the second embodiment of the present invention will be described.

  When water and a chemical solution are mixed on the upstream side of the mixer and flowed in a state where the concentration of the chemical solution is temporarily high, the chemical solution that is partially concentrated in the flow path is flown into the fluid inlet 6. Then, it flows into the first flow path 7 and flows into the liquid chamber. The portion of the chemical solution having a high concentration is branched by the ten first through holes 24 communicating with the liquid chamber 10 and flows into the respective branch flow paths 23. The portion of the chemical liquid having a high concentration flowing into the branch flow path 23 fills the branch flow path 23 and then flows to the fluid outlet 12 through the junction. At this time, the chemical liquid flows along the taper portion 25 when flowing into the branch flow path 23 from the first through hole 24. Therefore, when the branch flow path 23 is filled, the chemical liquid can flow smoothly without causing a stay. Further, since the fluid flows along the tapered portion 28 when it flows into the second communication hole 27 from the branch flow path 23, the liquid stays smoothly without flowing, and the chemical liquid flows smoothly when moving from the branch flow path 23 to the junction portion. it can. The other actions of the second embodiment such as the action of the chemical liquid flowing through the branch flow passages 23 having different inner diameters are the same as those of the first embodiment, and thus the description thereof is omitted.

  Here, as for the 1st through-hole 24, it is desirable that each channel | path cross-sectional area is formed substantially the same. This is because the flow rate of the fluid divided by each of the first through holes 24 is constant, so that the fluid flowing into the mixer is divided approximately equally by the number of the first through holes 24 and each has a time difference. Since it flows by merging, it is preferable because the concentration distribution can be made uniform without unevenness. Similarly, it is desirable that the passage cross-sectional areas of the second communication holes 27 are substantially the same. This is because the fluid to be divided is joined at the joining portion 16 at a constant flow rate in the second communication hole 27, so that the concentration distribution of the fluid that flows by joining each other with a time difference can be made more uniform. Is preferred. Further, in the second embodiment, the first and second communication holes 24 and 27 branch into both the first continuous holes 24 of the main body 21 and the second communication holes 27 of the intermediate joint part 26. 23, taper portions 25 and 28 that gradually increase in diameter toward the inner peripheral surface are provided, but may be provided only on one of them as necessary.

  Further, as shown in FIG. 7, the second communication hole 32 may be provided at a position eccentric with respect to the central axis of each branch flow path 33. This is because the flow of the fluid in the branch channel 33 is changed by shifting the position where the second communication hole 32 communicates with the central axis of the first series hole 31 of the branch channel 33, It is preferable because the flow of the fluid at a position away from the central axis of the flow path 33 is prevented from being slower than the flow of the central axis, and the fluid can flow in the branch flow path 33 without any unevenness. The second communication hole 31 may be provided at a position eccentric with respect to the central axis of the branch flow path 33.

It is a schematic diagram of the piping flow path which shows the mixer of 1st embodiment of this invention. It is AA sectional drawing of FIG. It is a schematic diagram which shows the apparatus which measures the density | concentration of the fluid using the mixer of FIG. It is the graph which measured the density | concentration of the upstream of the mixer of FIG. It is the graph which measured the density | concentration of the downstream of the mixer of FIG. It is a longitudinal cross-sectional view which shows the mixer of 2nd embodiment of this invention. It is a longitudinal cross-sectional view which shows the other variation of the 2nd communicating hole of 2nd embodiment. It is a longitudinal cross-sectional view which shows the conventional static mixer. It is a schematic diagram which shows the stirring state of the fluid of the static mixer of FIG. It is a longitudinal cross-sectional view which shows the conventional branch dilution apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main-body part 2 Concave part 3, 3a-3j Branch flow path 4 1st through-hole 5 1st joint part 6 Fluid inlet 7 1st flow path 8 Tapered part 9 Female thread part 10 Liquid chamber 11 Second joint part 12 Fluid outlet 13 Second flow path 14 Tapered portion 15 Female thread portion 16 Merged portion 21 Body portion 22 Recessed portion 23 Branch flow channel 24 First continuous hole 25 Tapered portion 26 Intermediate joint portion 27 Second communication hole 28 Tapered portion 31 First continuous hole 32 Second communication hole 33 Branch flow path

Claims (6)

A fluid inlet;
A first flow path communicating with the fluid inlet;
A liquid chamber communicating with the first flow path;
A plurality of branch passages communicating with the liquid chamber via each of the first series of through holes;
A merging section where the branch flow paths merge;
A second flow path communicating with the merge portion;
A fluid outlet communicating with the second flow path,
The mixer characterized in that the plurality of branch flow paths are formed with different inner diameters. A concave portion is provided on one side surface, and a plurality of bottomed cylindrical branch channels having different inner diameters are provided on the other side surface, and the first series of holes communicating the bottom surface of the recess and the bottom surface of the branch channel are respectively provided. A main body having,
A first flow path, and a first joint portion having a tapered portion that gradually decreases in diameter from one side surface toward the inner peripheral surface of the first flow channel, and the tapered portion forms a liquid chamber together with the concave portion of the main body portion;
A second flow path and a taper portion that gradually decreases in diameter from one side surface toward the inner peripheral surface of the second flow path, and the taper portion forms a merge portion that communicates with the branch flow path of the main body portion. The mixer according to claim 1, further comprising two joint portions.   The intermediate joint part which has between the said main-body part and the said 2nd joint part, and has a 2nd communicating hole respectively connected from the said branch flow path to the said junction part is further provided. Item 3. The mixer according to Item 2.   The mixer according to claim 3, wherein the first communication hole or the second communication hole is provided at a position eccentric with respect to a central axis of each of the branch flow paths.   The diameter of each of the main body portion and the second joint hole of each of the intermediate joint portions is gradually increased from the communication hole toward the inner peripheral surface of the branch flow path. The mixer according to claim 3 or 4, wherein a tapered portion is provided.   The mixer according to any one of claims 1 to 5, wherein the opening areas of the first through holes are formed to be substantially the same.

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