JP2022189209A - Different kind of liquid mixing device and water treatment facility - Google Patents

Abstract

To provide a different kind of liquid mixing device capable of mixing a second liquid injected from an injection port into a flow course with a first liquid by sufficiently agitating the second liquid within the flow course.SOLUTION: In a different kind of a liquid mixing device 4 for injecting a second liquid 16 into a flow course 20 with a first liquid 2 flowing to mix them, a plurality of line mixers 9, 10 are connected in series, the respective line mixers 9, 10 sequentially have a second straight pipe part 32, an enlarged diameter part 33 with an inner diameter becoming larger as it goes downstream, and a third straight pipe part 34 having an inner diameter larger than the inner diameter of the second straight pipe part 32 from an upstream side of the flow course 20, an injection port 38 of an injection course 37 for injecting the second liquid 16 into the first liquid 2 is plunged into the line mixer 9 at an uppermost upstream end to be open, and the injection port 38 is opened at a position corresponding to the inside of the third straight pipe part 34 in an axial direction L of the flow course 20 and at a middle vicinity position between an inner surface of the second straight pipe 32 and an inner surface of the third straight pipe part 34 in the radial direction R of the flow course 20.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to a dissimilar liquid mixing device for injecting and mixing a second liquid into a flow path through which a first liquid flows, and to a water treatment facility provided with the dissimilar liquid mixing device.

Conventionally, as this type of liquid mixing device, there is a cleaning liquid generator 101 that mixes a detergent 111 with water 110 to generate a cleaning liquid 112, as shown in FIG. The cleaning liquid generator 101 includes a container body 102, a first channel 105 formed in the container body 102 from an inlet 103 to an outlet 104, and a channel cross-sectional area , an injection port 108 formed in a peripheral wall portion 107 of the venturi portion 106, and a second flow path 109 communicating with the injection port 108.

The injection port 108 is formed in a projecting portion 107a projecting radially inwardly from the peripheral wall portion 107 of the venturi portion 106. As shown in FIG.

Water 110 flows into the vessel 102 from the inlet 103 and flows through the first channel 105 . Also, the detergent 111 is injected into the first channel 105 from the inlet 108 through the second channel 109 . As a result, the water 110 and the detergent 111 are mixed in the first channel 105 to generate the cleaning liquid 112 , and the cleaning liquid 112 flows out of the container body 102 through the outlet 104 .

At this time, since the flow of the water 110 is accelerated in the venturi section 106 , a high-velocity flow is generated downstream of the venturi section 106 .

Incidentally, the cleaning liquid generator 101 as described above is described in Patent Document 1 below, for example.

JP 2019-136648

However, in the above-described conventional type, since the injection port 108 is provided in the venturi portion 106 , the detergent 111 injected from the injection port 108 into the first flow path 105 rides on the flow of the water 110 accelerated by the venturi portion 106 . Therefore, there is a problem that the detergent 111 cannot be sufficiently agitated in the first flow path 105 because the detergent 111 flows to the downstream side in a short period of time.

For example, when the cleaning liquid generator 101 as described above is used as a device for mixing different types of liquids, and a coagulant is injected into and mixed with raw water containing suspended solids, the raw water flows into the vessel 102 from the inlet 103. , flows through the first channel 105 . Also, the coagulant is injected into the first channel 105 from the inlet 108 through the second channel 109 .

However, even in this case, similarly to the above, the flocculant injected from the injection port 108 into the first flow path 105 rides on the flow of the raw water accelerated by the venturi section 106 and flows downstream at once in a short period of time. Therefore, there is a problem that the coagulant cannot be sufficiently stirred in the first channel 105 . In addition, the protrusion 107a formed on the peripheral wall portion 107 of the venturi portion 106 creates a retention area of the raw water downstream of the inlet 108, and the flocculant injected from the inlet 108 faces the retention area. or the injection port 108.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dissimilar liquid mixing apparatus and water treatment equipment capable of sufficiently agitating a second liquid injected into a flow path from an inlet into the flow path to mix it with the first liquid. and

In order to achieve the above object, the first invention is a heterogeneous liquid mixing apparatus for injecting and mixing a second liquid into a flow path through which a first liquid flows, comprising:
Multiple line mixers are connected in series,
Each line mixer has, from the upstream side of the flow path, a second straight pipe portion, an enlarged diameter portion whose inner diameter increases toward the downstream side, and a third straight pipe portion whose inner diameter is larger than that of the second straight pipe portion. have sequentially,
the inlet at the tip of the injection path for injecting the second liquid into the first liquid projects into at least the line mixer at the most upstream end and opens;
The injection port is opened at a position corresponding to the inside of the third straight pipe portion in the axial direction of the flow path and at a position near the middle between the inner surface of the second straight pipe portion and the inner surface of the third straight pipe portion in the radial direction of the flow path. It is what we are doing.

According to this, when the first liquid flows through each line mixer, the first liquid passes through the second straight pipe portion of each line mixer and the flow path is expanded at the enlarged diameter portion. Therefore, in the area downstream from the upstream end of the enlarged diameter portion of each line mixer, the flow of the first liquid separates from the inner surface of the flow path, the velocity gradient increases, and the inner surface of the enlarged diameter portion and the third straight pipe A vortex is generated along the inner surface of the part.

In this state, by injecting the second liquid from the inlet of the injection path into the third straight pipe portion of the line mixer at the most upstream end, the second liquid is generated throughout the enlarged diameter portion and the third straight pipe portion. Injected into a vortex and stirred by the vortex. As a result, when the second liquid flows through the line mixer at the most upstream end, the second liquid quickly diffuses widely in the third straight pipe portion from inside the expanded diameter portion of the line mixer at the most upstream end.

After that, when the mixed liquid of the first liquid and the second liquid flows through the line mixer connected to the downstream side of the line mixer at the most upstream end, the mixed liquid is It is further agitated by the eddy currents generated inside and across. Thereby, when the second liquid flows through the line mixer on the downstream side, the second liquid is quickly dispersed in a wide range from the inside of the expanded diameter portion of the line mixer on the downstream side to the inside of the third straight pipe portion.

Therefore, the first liquid and the second liquid can be sufficiently and uniformly mixed as compared with the case where only one line mixer is used to mix the first liquid and the second liquid.

A second aspect of the present invention is a heterogeneous liquid mixing device for injecting and mixing a second liquid into a flow path in which a first liquid flows,
Multiple line mixers are connected in series,
Each line mixer has, from the upstream side of the flow path, a second straight pipe portion, an enlarged diameter portion whose inner diameter increases toward the downstream side, and a third straight pipe portion whose inner diameter is larger than that of the second straight pipe portion. have sequentially,
the inlet at the tip of the injection path for injecting the second liquid into the first liquid projects into at least the line mixer at the most upstream end and opens;
The inlet is opened at a position corresponding to the inside of the enlarged diameter portion in the axial direction of the flow path, and at a position near the middle between the inner surface of the second straight pipe portion and the inner surface of the enlarged diameter portion in the radial direction of the flow path. and
The predetermined portion of the inner surface of the enlarged diameter portion is a portion facing outward in the radial direction of the flow path from the inlet.

According to this, when the first liquid flows through each line mixer, the first liquid passes through the second straight pipe portion of each line mixer and the flow path is expanded at the enlarged diameter portion. Therefore, in the area downstream from the upstream end of the enlarged diameter portion of each line mixer, the flow of the first liquid separates from the inner surface of the flow path, the velocity gradient increases, and the inner surface of the enlarged diameter portion and the third straight pipe A vortex is generated along the inner surface of the part.

In this state, by injecting the second liquid from the injection port of the injection path into the expanded diameter portion of the line mixer at the most upstream end, the second liquid flows into the vortex generated in the expanded diameter portion and the third straight pipe portion. is injected into and agitated by the vortex. As a result, when the second liquid flows through the line mixer at the most upstream end, the second liquid quickly diffuses widely in the third straight pipe portion from inside the expanded diameter portion of the line mixer at the most upstream end.

After that, when the mixed liquid of the first liquid and the second liquid flows through the line mixer connected to the downstream side of the line mixer at the most upstream end, the mixed liquid is It is further agitated by the eddy currents generated inside and across. Thereby, when the second liquid flows through the line mixer on the downstream side, the second liquid is quickly dispersed in a wide range from the inside of the expanded diameter portion of the line mixer on the downstream side to the inside of the third straight pipe portion.

Therefore, the first liquid and the second liquid can be sufficiently and uniformly mixed as compared with the case where only one line mixer is used to mix the first liquid and the second liquid.

In the apparatus for mixing different types of liquids according to the third aspect of the present invention, each line mixer has a first straight pipe section upstream of the second straight pipe section and a reduced diameter section whose inner diameter decreases toward the downstream side in sequence,
The inner diameter of the first straight pipe portion is larger than the inner diameter of the second straight pipe portion.

According to this, when the first liquid flows through each line mixer, it flows through the first straight pipe portion, passes through the diameter-reduced portion, and is accelerated when flowing through the second straight pipe portion, and the flow path is expanded at the diameter-enlarged portion. be. Thus, by making the inner diameter of the first straight pipe portion larger than the inner diameter of the second straight pipe portion, it is possible to suppress the pressure loss when the first liquid flows through the flow path of each line mixer.

In the device for mixing different liquids in the fourth aspect of the present invention, the first straight pipe portion and the third straight pipe portion have the same diameter,
The third straight pipe portion of the line mixer on the upstream side and the first straight pipe portion of the line mixer on the downstream side are connected via connecting pipes having the same diameter.

According to this, in the region downstream from the upstream end of the enlarged diameter portion of each line mixer, the flow of the first liquid separates from the inner surface of the flow path, the velocity gradient increases, and the inner surface of the enlarged diameter portion and the third A vortex is generated along the inner surface of the straight pipe portion and further along the inner surface of the connecting pipe.

As a result, it is preferable to connect the third straight pipe portion of the upstream line mixer and the first straight pipe portion of the downstream line mixer via the connecting pipe, without using the connecting pipe. A longer vortex generation region can be ensured in the flow direction than in the case where the third straight pipe portion of the line mixer is directly connected to the first straight pipe portion of the line mixer on the downstream side. Therefore, the first liquid and the second liquid can be sufficiently and uniformly mixed.

In the apparatus for mixing different types of liquids according to the fifth aspect of the present invention, the distance from the injection port of the line mixer at the most upstream end to the upstream end of the expanded diameter portion of the line mixer on the downstream side is within 1000 mm.

According to this, the velocity gradient is maximized at the enlarged diameter portion of each line mixer, and becomes smaller with increasing distance from the enlarged diameter portion toward the downstream side. For this reason, the stirring force is attenuated as the distance from the enlarged diameter portion of each line mixer increases toward the downstream side.

Therefore, before the stirring force of the line mixer at the most upstream end is significantly attenuated, the stirring force of the line mixer on the downstream side becomes maximum at the enlarged diameter portion, so the stirring force continues for a long time. The first liquid and the second liquid can be sufficiently and uniformly mixed.

A sixth invention is a water treatment facility comprising the device for mixing different liquids according to any one of the first to fifth inventions,
the second liquid is a liquid flocculant;
the first liquid is water containing a substance to be agglomerated by the aggregating agent;
A flocculating and mixing device is connected to the downstream side of the line mixer at the most downstream end,
The aggregating and mixing device has at least one mixing vessel in which an upward flow path is formed between a lower inlet and an upper outlet.

According to this, in the heterogeneous liquid mixing device, the coagulant is injected into water and sufficiently stirred and mixed, the mixed liquid of water and coagulant is supplied from the heterogeneous liquid mixing device to the mixing tank, and the upward flow of the mixing tank Agglomerated flocs formed in the mixture grow and coarsen due to slow stirring in the passage.

At this time, since the flocculant and water are sufficiently and uniformly stirred and mixed in the device for mixing different types of liquids, sufficiently coarse flocs can be obtained with a small number of mixing tanks.

As described above, according to the present invention, the second liquid injected from the inlet into the flow path can be sufficiently stirred in the flow path and mixed with the first liquid.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram of the water-treatment facility provided with the heterogeneous liquid mixing apparatus in the 1st Embodiment of this invention. It is a figure of a dissimilar liquid mixing apparatus and an agglomeration mixing apparatus of a water treatment facility same. It is a cross-sectional view of the device for mixing different types of liquids. Fig. 3 is a partially enlarged cross-sectional view of a line mixer on the most upstream side of the device for mixing different kinds of liquids; It is sectional drawing which shows the flow inside the line mixer of the most upstream side of a heterogeneous liquid mixing apparatus same, and shows the case where test sample S2 is used. It is sectional drawing which shows the flow inside the line mixer of the most upstream side of a heterogeneous liquid mixing apparatus same, and shows the case where test sample S1 is used. It is sectional drawing which shows the flow inside the line mixer of the most upstream side of a heterogeneous liquid mixing apparatus same, and shows the case where test sample S3 is used. It is sectional drawing which shows the flow inside the line mixer of the most upstream side of a heterogeneous liquid mixing apparatus same, and shows the case where test sample S4 is used. FIG. 6 is a partially enlarged cross-sectional view of a line mixer on the most upstream side of the device for mixing different types of liquids according to the second embodiment of the present invention; It is a partially enlarged cross-sectional view showing the flow inside the line mixer on the most upstream side of the device for mixing different kinds of liquids. It is a cross-sectional view of a dissimilar liquid mixing device according to a third embodiment of the present invention. It is a figure of a dissimilar liquid mixing apparatus and an aggregation mixing apparatus same. FIG. 4 is a graph showing the distribution of velocity gradients of a line mixer; FIG. It is a graph which shows distribution of the velocity gradient in a heterogeneous liquid mixing apparatus, and shows the case where only one line mixer is used independently. It is a graph which shows distribution of the velocity gradient in a heterogeneous liquid mixing apparatus, and shows the case where two line mixers are directly connected and used. It is a graph which shows distribution of the velocity gradient in a heterogeneous liquid mixing apparatus, and shows the case where two line mixers were connected through a connecting pipe. It is a cross-sectional view of a dissimilar liquid mixing device according to a fourth embodiment of the present invention. 1 is a cross-sectional view of a conventional line mixer; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
In the first embodiment, as shown in FIG. 1, 1 is a water treatment facility such as water purification, and a raw water storage tank 3 for storing raw water 2 (an example of a first liquid) from the upstream side to the downstream side , a heterogeneous liquid mixing device 4, an aggregation and mixing device 5, a membrane separation device 6 (an example of a solid-liquid separation device), and a treatment obtained by solid-liquid separation of the raw water 2 by membrane filtration in the membrane separation device 6 and a treated water tank 8 for collecting water 7 .

The raw water storage tank 3, the dissimilar liquid mixing device 4, the aggregation and mixing device 5, the membrane separation device 6, and the treated water tank 8 are connected via pipe lines 11 to 14, respectively.

As shown in FIGS. 2 and 3, the dissimilar liquid mixing apparatus 4 injects and mixes a liquid coagulant 16 (an example of a second liquid) into a flow path 20 through which the raw water 2 flows. The raw water 2 contains suspended matter (an example of the matter to be agglomerated) that is agglomerated by the flocculant 16 . Also, the aggregating agent 16 is a liquid in which, for example, polyaluminum chloride or the like is dissolved.

The dissimilar liquid mixing device 4 has two (a plurality of) line mixers 9 and 10 connected in series. Each line mixer 9, 10 has a tubular body 21 and flanges 22, 23 provided at opposite ends of the body 21, respectively.

Of these, the inlet-side flange 22 of the line mixer 9 on the most upstream side is joined to the flange 17 provided in the pipeline 11, and the outlet-side flange 23 of the line mixer 10 connected downstream is connected to the pipeline 12. It is joined to a flange 18 provided. Further, the outlet-side flange 23 of the most upstream line mixer 9 and the inlet-side flange 22 of the downstream line mixer 10 are joined.

A flow path 20 is formed in each body 21 of each line mixer 9, 10 and has an inlet 25 at its upstream end and an outlet 26 at its downstream end.

The body 21 of each of the line mixers 9 and 10 includes, from the upstream side of the flow path 20, a first straight tube portion 30 and a reduced diameter portion 31 whose inner diameter gradually decreases toward the downstream side of the first straight tube portion 30. a second straight pipe portion 32 having an inner diameter equal to the inner diameter of the downstream end portion of the diameter-reduced portion 31; and a third straight tube section 34 having an inner diameter equal to the inner diameter of the downstream end of section 33 .

The inner diameter D of the third straight pipe portion 34 is larger than the inner diameter d of the second straight pipe portion 32, and the ratio between the inner diameter D and the inner diameter d is set in the range of about 1.5:1 to 3:1. The inner diameter D′ of the first straight pipe portion 30 is larger than the inner diameter d of the second straight pipe portion 32 and the same as the inner diameter D of the third straight pipe portion 34 .

Further, the enlarged diameter portion 33 expands along a gentle slope from the downstream end of the second straight pipe portion 32, and the inclination angle α of the enlarged diameter portion 33 with respect to the axis 50 of the flow path 20 is 30° to 50°. ° range.

An injection pipe 37 (an example of an injection route) for injecting the coagulant 16 into the raw water 2 is connected to the main body 21 of the line mixer 9 on the most upstream side. An injection port 38 formed at the tip of the injection pipe 37 is located facing the inside of the third straight pipe portion 34 in the axial direction L of the flow path 20 and is located in the second straight pipe portion 34 in the radial direction R of the flow path 20. It is open at a position near the middle between the inner surface of the portion 32 and the inner surface of the third straight pipe portion 34 .

The direction of injection of the flocculant 16 from the injection port 38 into the third straight pipe portion 34 is perpendicular to the axis 50 of the flow path 20 .

As shown in FIG. 4, the dimension from the injection port 38 of the injection pipe 37 to the inner surface of the third straight pipe portion 34 in the radial direction R is defined as B, and the dimension from the injection port 38 of the injection pipe 37 in the radial direction R to the second Assuming that the dimension to the inner surface of the straight pipe portion 32 is C, the position near the middle between the inner surface of the second straight pipe portion 32 and the inner surface of the third straight pipe portion 34 is determined by the following relational expressions [1] and [2]. It is a position that satisfies at the same time.
0.1×(D−d)≦B Relational expression [1]
0.15×(D−d)≦C Relational expression [2]
An injection port 38 of the injection pipe 37 is opened at a position immediately after the enlarged diameter portion 33 . Here, assuming that the downstream side of the length corresponding to the inner diameter D of the third straight pipe portion 34 from the upstream end portion 34a of the third straight pipe portion 34 in the axial direction L is the downstream limit position E, The immediately following position is defined as a position within a region F from the upstream end 34a of the third straight pipe portion 34 to the downstream limit position E in the axial direction L. As shown in FIG.

As shown in FIGS. 1 and 2, the aggregation and mixing device 5 is provided downstream of the heterogeneous liquid mixing device 4, and a mixture 40 of the raw water 2 mixed by the heterogeneous liquid mixing device 4 and the flocculant 16 is mixed. It is a type of slow stirring device for growing and coarsening the agglomerated flocs formed inside.

The aggregation and mixing device 5 has two (a plurality of) mixing tanks 51 and 52, a connecting conduit 53 connected between the mixing tanks 51 and 52, and a meandering channel 54 meandering in the vertical direction. ing. Each of the mixing tanks 51 and 52 is a vertically long cylindrical tank closed at both upper and lower ends, and has an inlet 55 at the bottom and an outlet 56 at the top.
The upper end of the connecting pipe line 53 is connected to the outlet port 56 of the mixing tank 51 on the upstream side, and the lower end of the connecting pipe line 53 is connected to the inlet port 55 of the mixing tank 52 on the downstream side. The meandering flow path 54 also has an upward flow path 58 formed in the mixing tanks 51 and 52 and a downward flow path 59 formed in the connecting pipe line 53 . An upward flow path 58 is formed between the inflow port 55 and the outflow port 56 . The inner diameter of each of the mixing tanks 51 and 52 is larger than the inner diameter of the connecting pipe 53 , so that the cross-sectional area of the upward channel 58 is larger than the cross-sectional area of the downward channel 59 .

Further, the line mixer 10 on the downstream side is connected to the inlet 55 of the mixing tank 51 on the upstream side through the pipe line 12 .

As shown in FIG. 1, the membrane separation device 6 performs solid-liquid separation by membrane filtration of a mixed liquid 40 of the raw water 2 and the coagulant 16 mixed by the heterogeneous liquid mixing device 4 .

The operation of the above configuration will be described below.

As shown in FIG. 1, the raw water 2 is sequentially supplied from the raw water storage tank 3 to the line mixer 9 on the upstream side and the line mixer 10 on the downstream side of the heterogeneous liquid mixing device 4. , the raw water 2 and the flocculant 16 are mixed to form a mixture 40 . After that, the mixed liquid 40 is supplied to the mixing tank 51 on the upstream side of the aggregation and mixing device 5, and further supplied from the mixing tank 51 on the upstream side to the mixing tank 52 on the downstream side through the connecting pipe line 53. Aggregated flocs formed in the mixture 40 grow and coarsen. After that, the mixed liquid 40 is supplied from the mixing tank 52 to the membrane separator 6 for solid-liquid separation, and the treated water 7 obtained in the membrane separator 6 is collected in the treated water tank 8 .

In such a series of water treatments, the raw water 2 and the flocculant 16 are mixed and stirred in the line mixer 9 on the upstream side as follows.

As shown in FIG. 3, the raw water 2 supplied from the raw water storage tank 3 to the line mixer 9 on the upstream side flows into the flow path 20 from the inlet 25 of the line mixer 9, flows through the flow path 20, and exits at the outlet 26. flow out from At this time, after flowing through the first straight pipe portion 30 , the raw water 2 is accelerated while flowing through the second straight pipe portion 32 via the reduced diameter portion 31 , and is gradually expanded in the enlarged diameter portion 33 . Therefore, as shown in FIG. 5 , the flow of the raw water 2 separates from the inner surface of the flow path 20 in the area downstream from the upstream end of the enlarged diameter portion 33 , the velocity gradient increases, and the enlarged diameter portion 33 A vortex 45 is generated along the inner surface and the inner surface of the third straight pipe portion 34 .

A point 46 indicates a separation point where the flow of the raw water 2 separates at the upstream end of the enlarged diameter portion 33 . A main stream 47 is formed in the central portion of the downstream side of the second straight pipe portion 32 , in which the raw water 2 flows from the upstream side to the downstream side at a high flow velocity, and a vortex 45 is generated around the main stream 47 .

In this state, by injecting the flocculant 16 from the injection port 38 of the injection pipe 37 into the third straight pipe section 34 of the line mixer 9 on the upstream side, the flocculant 16 is caused to flow in the vortex in the third straight pipe section 34. 45 and is also reversed upstream of inlet 38 by swirl 45 . As a result, the flocculant 16 is dispersed and supplied from the enlarged diameter portion 33 to the entire third straight pipe portion 34, and the agitation is further promoted. is sufficiently and uniformly mixed, the suspended matter (to-be-agglomerated matter) contained in the raw water 2 reacts quickly with the flocculant 16 to initiate aggregation, and on the downstream side of the line mixer 9 on the upstream side, flocculation is formed.

As a result, it is possible to prevent the flocculant 16 from precipitating in the third straight pipe portion 34 on the downstream side of the injection port 38, resulting in the problem that the third straight pipe portion 34 is clogged with the precipitated flocculant 16. can prevent the occurrence of

In addition, the injection port 38 of the injection pipe 37 is opened at a position immediately after the enlarged diameter portion 33 in the axial direction L of the flow path 20, and is located in the radial direction R of the flow path 20 at the second straight pipe portion 32. and the inner surface of the third straight pipe portion 34, i.e., at a position satisfying the above-mentioned relational expressions [1] and [2] at the same time. It can be reliably injected into the vortex 45 generated in the tube portion 34 .

For example, assuming that the inner diameter D of the third straight pipe portion 34 is 25 mm and the inner diameter d of the second straight pipe portion 32 is 13 mm, the injection port 38 of the injection pipe 37 will flow into the third straight pipe portion based on the above relational expression [1]. The dimension B to the inner surface of 34 is set to 1.2 mm or more, and the dimension C from the injection port 38 to the inner surface of the second straight pipe portion 32 is set to 1.8 mm or more based on the above relational expression [2]. It is

Table 1 below shows the mixture flowing out to the downstream side of the upstream line mixer 9 when the inner diameter D is 25 mm, the inner diameter d is 13 mm, and the dimension B is set in four stages of 1 mm, 3 mm, 6 mm, and 12.5 mm. It shows the experimental results of examining the total number of particles in the liquid 40 and the presence or absence of precipitation of the coagulant 16 in the third straight pipe section 34 of the line mixer 9 on the upstream side.

The total number of particles is the total number of fine particles (particles of 0.1 to 0.4 μm) contained in the mixed liquid 40 of the raw water 2 and the flocculant 16, and is a standard total number of particles. are denoted as N. When the raw water 2 and the flocculant 16 are sufficiently and uniformly mixed in the line mixer 9 on the upstream side, a large number of fine particles in the liquid mixture 40 aggregate and become coarse on the downstream side of the line mixer 9. Therefore, the total number of microparticles contained in the mixed liquid 40 is reduced. Therefore, it means that the smaller the total number of particles, the more the aggregating agent 16 is sufficiently stirred and mixed, and the higher the aggregating effect.

According to Table 1 above, in the case of the test sample S2 in which the dimension B is set to 3 mm, the dimension C is 3 mm, and the relational expressions [1] [2] (that is, 1.2 mm ≤ B and 1.8 mm ≤ Since C) is satisfied at the same time, the total number of particles is small, the aggregating agent 16 does not precipitate, and the aggregating effect is high. In this case, as shown in FIG. 5 , the flocculant 16 is injected from the injection port 38 into the central portion of the vortex 45 , so that the vortex 45 quickly diffuses the coagulant 16 upstream and downstream of the injection port 38 . As a result, the raw water 2 and the flocculant 16 are sufficiently and uniformly mixed. In addition, in the case of the test sample S1 in which the dimension B is set to 1 mm, the dimension C is 5 mm, and the above relational expressions [1] [2] ( That is, since 1.2 mm ≤ B and 1.8 mm ≤ C) are not satisfied at the same time, the injected coagulant 16 is not sufficiently stirred and mixed with the raw water 2, and a large number of total particles are detected. , it can be seen that the aggregation effect is low. Furthermore, a phenomenon in which the unreacted flocculant 16 precipitates in the downstream region of the injection port 38 was also confirmed. In this case, as shown in FIG. 6, the flocculant 16 is injected from the injection port 38 into the vicinity of the inner surface of the third straight pipe portion 34 (near), but the flow velocity of the raw water 2 in the vicinity of the inner surface of the third straight pipe portion 34 is is very slow, much of the flocculant 16 stays around the inlet 38 and is difficult to diffuse.

In addition, in the case of the test sample S3 in which the dimension B is set to 6 mm, the dimension C is 0 mm, and the above relational expressions [1] [2] (that is, 1.2 mm ≤ B and 1.8 mm ≤ C) are simultaneously satisfied. Since it is not satisfied, the injected coagulant 16 is not sufficiently stirred and mixed with the raw water 2, and a large number of total particles are detected, indicating that the coagulation effect is low. Furthermore, a phenomenon in which the unreacted flocculant 16 precipitates in the downstream region of the injection port 38 was also confirmed. In this case, as shown in FIG. 7, since the flocculant 16 is injected into the flow from the upstream side to the downstream side of the vortex flow 45, most of the flocculant 16 joins the main stream 47 of the raw water 2 immediately after injection. As a result, it flows downstream of the injection port 38 and is difficult to diffuse upstream of the injection port 38 .

Furthermore, in the case of the test sample S4 in which the dimension B is set to 12.5 mm, the dimension C is -6.5 mm, and the above relational expressions [1] [2] (that is, 1.2 mm ≤ B and 1.8 mm Since ≦C) is not satisfied at the same time, the injected coagulant 16 is not sufficiently stirred and mixed with the raw water 2, and a large number of total particles are detected, indicating that the coagulation effect is low. Furthermore, a phenomenon in which the unreacted flocculant 16 precipitates in the downstream region of the injection port 38 was also confirmed. In this case, as shown in FIG. 8, most of the flocculant 16 injected into the third straight pipe portion 34 from the injection port 38 is mainly not caused by the eddy current 45 inside the third straight pipe portion 34, but by the flow velocity Since it is injected into the fast main flow 47, it does not have time to be sufficiently stirred in the third straight pipe portion 34, and is flowed downstream at once on the main flow 47 in a short period of time. As a result, the number of aggregated flocs formed in the mixed liquid 40 on the downstream side of the line mixer 9 on the upstream side is reduced, and many fine particles remain in the mixed liquid 40, so the total number of particles is reduced. become extremely numerous.

After that, when the mixed liquid 40 flows from the upstream line mixer 9 through the downstream line mixer 10, it flows along the inner surface of the enlarged diameter portion 33 and the inner surface of the third straight pipe portion 34 of the downstream line mixer 10. It is further agitated by the eddies 45 that are generated. As a result, when the flocculant 16 flows through the line mixer 10 on the downstream side, the flocculant 16 is quickly dispersed over a wide area from the enlarged diameter portion 33 of the line mixer 10 on the downstream side to the third straight pipe portion 34 .

Therefore, the use of two line mixers 9 and 10 sufficiently mixes the raw water 2 and the flocculant 16 compared to the case where only one line mixer is used to mix the raw water 2 and flocculant 16. It can be mixed evenly.

Thereafter, as shown in FIG. 2, when the mixture 40 of the raw water 2 and the flocculant 16 flows through the mixing tanks 51 and 52, the average flow velocity of the mixture 40 decreases. is slowly agitated, particles in the liquid mixture 40 tend to associate with each other, and aggregated flocs grow and coarsen. As a result, as shown in FIG. 1, when the liquid mixture 40 is subjected to solid-liquid separation in the membrane separation device 6, even if flocculated flocs adhere to the membrane surface of the filtration membrane of the membrane separation device 6, the filtration membrane is removed by backwashing. can be thoroughly washed to restore filtration performance.

Table 2 below shows the results of examining the evaluation of the state of aggregation. Of these, the condition (1) is a form in which only one line mixer 9 is used alone, and two mixing tanks 51 and 52 are connected downstream of the line mixer 9 . The condition (2) is that the two line mixers 9 and 10 are directly connected as in the first embodiment, and two mixing tanks 51 and 52 (see FIG. 2) are connected.

The numerical value described in the column of water sampling (1) indicates the amount [mg/liter] of residual aluminum contained in the mixed liquid 40 sampled from the upper part of the mixing tank 51 on the upstream side. The numerical value described in the column of water sampling (2) indicates the amount [mg/liter] of residual aluminum contained in the mixed liquid 40 sampled from the upper part of the mixing tank 52 on the downstream side.

Incidentally, the residual aluminum is the unreacted aluminum extracted from the aluminum derived from the aggregating agent 16 .

It is judged that the larger the amount of residual aluminum, the larger the amount of unreacted coagulant 16 and the worse the state of aggregation. Conversely, the smaller the amount of residual aluminum, the less the unreacted flocculant 16 and the better the agglomeration state.

According to Table 2 above, the difference between the amount of residual aluminum under condition (1) and the amount of residual aluminum under condition (2) is 0% in water sampling (1), but the difference is 0% in water sampling (2). is -9.8%. These numerical values are calculated as follows.
(0.0252−0.0252)×100/0.0252=0 [%]
(0.0193−0.0214)×100/0.0214=−9.8[%]
As a result, since the amount of residual aluminum in the mixing tank 52 on the downstream side is greatly reduced, it can be seen that the agglomeration reaction is well carried out in the mixing tank 52 on the downstream side. Since the two line mixers 9 and 10 are directly connected on the upstream side of the mixing tanks 51 and 52, compared to the case where one line mixer is used alone, both line mixers 9 and 10 2 and the flocculant 16 are sufficiently and uniformly mixed.

In the first embodiment, the position of the injection port 38 in the radial direction R is set to a position that satisfies the above relational expressions [1] and [2]. You may set it to the position where it becomes equal.

(Second embodiment)
In the above-described first embodiment, as shown in FIG. 4, the injection port 38 of the injection pipe 37 is located inside the third straight pipe portion 34. However, in the second embodiment described below, as shown in FIG. , FIG. 10, the inlet 38 is located within the enlarged diameter portion 33 . That is, the injection port 38 is located at a position facing the inside of the enlarged diameter portion 33 in the axial direction L of the flow path 20, and the inner surface of the second straight pipe portion 32 and the enlarged diameter portion 33 in the radial direction R of the flow path 20. is opened at a position near the middle of the inner surface of the .

The predetermined point G is a point facing outward in the radial direction R of the flow path 20 from the injection port 38 .

The direction of injection of the flocculant 16 from the inlet 38 into the enlarged diameter portion 33 is perpendicular to the axis 50 of the flow path 20 .

Let B be the dimension from the injection port 38 in the radial direction R to a predetermined point G on the inner surface of the enlarged diameter portion 33, and let C be the dimension from the injection port 38 to the inner surface of the second straight pipe portion 32 in the radial direction R. , the position near the middle between the inner surface of the second straight pipe portion 32 and the predetermined point G on the inner surface of the enlarged diameter portion 33 is a position that simultaneously satisfies the following relational expressions [1] and [2].
0.1×(D−d)≦B Relational expression [1]
0.15×(D−d)≦C Relational expression [2]
The operation of the above configuration will be described below.

As shown in FIG. 10, by injecting the flocculant 16 into the enlarged diameter portion 33 of the line mixer 9 on the upstream side from the injection port 38, the flocculant 16 is injected into the enlarged diameter portion 33 of the line mixer 9 on the upstream side. and the inside of the third straight pipe portion 34 and is sufficiently stirred by the vortex 45 . As a result, the flocculant 16 is rapidly diffused over a wide area from the enlarged diameter portion 33 to the third straight pipe portion 34, so that the raw water 2 and the flocculant 16 are sufficiently and uniformly distributed in the third straight pipe portion 34. Suspended matter mixed and contained in the raw water 2 quickly reacts with the flocculant 16 to initiate flocculation, forming flocs on the downstream side of the line mixer 9 on the upstream side.

In addition, the injection port 38 is positioned near the middle between the inner surface of the second straight tube portion 32 and the inner surface of the enlarged diameter portion 33 in the radial direction R of the flow path 20, that is, the relational expression [1] [2] described above. ] at the same time, the coagulant 16 can be reliably injected from the inlet 38 into the vortex 45 generated in the enlarged diameter portion 33 of the line mixer 9 on the upstream side.

After that, when the mixed liquid 40 of the raw water 2 and the flocculant 16 flows from the upstream line mixer 9 through the downstream line mixer 10, the inner surface of the enlarged diameter portion 33 of the downstream line mixer 10 and the third straight line. It is further agitated by the vortex 45 generated along the inner surface of the tube portion 34 . As a result, when the flocculant 16 flows through the line mixer 10 on the downstream side, the flocculant 16 is quickly dispersed over a wide area from the enlarged diameter portion 33 of the line mixer 10 on the downstream side to the third straight pipe portion 34 .

Although the two line mixers 9 and 10 are connected in series in the first and second embodiments, three or more line mixers may be connected in series.

(Third Embodiment)
In the above-described first embodiment, as shown in FIG. 3, the line mixer 9 on the upstream side and the line mixer 10 on the downstream side are directly connected, but in the third embodiment described below, As shown in FIGS. 11 and 12, the line mixer 9 on the upstream side and the line mixer 10 on the downstream side are connected via a connecting pipe 65 with a predetermined spacing.

The connection pipe 65 has a straight pipe portion 66 and connection flanges 67 and 68 provided at both ends of the straight pipe portion 66 . The inner diameter Da of the straight pipe portion 66 is the same as the inner diameter D′ of the first straight pipe portion 30 and the inner diameter D of the third straight pipe portion 34 of both line mixers 9 and 10 .

The outlet side flange 23 of the upstream line mixer 9 and one connection flange 67 of the connection pipe 65 are joined, and the inlet side flange 22 of the downstream line mixer 10 and the other connection flange 68 of the connection pipe 65 are connected. is joined.

The distance A from the injection port 38 of the line mixer 9 at the most upstream end to the upstream end portion 33a of the expanded diameter portion 33 of the line mixer 10 at the downstream side is set within 1000 mm. It should be noted that the distance A is preferably 520 mm to 700 mm.

In addition, the aggregation and mixing device 5 has only one mixing tank 51 .

The operation of the above configuration will be described below.

In the area downstream from the upstream end 33a of the enlarged diameter portion 33 of each line mixer 9, 10, the flow of the raw water 2 separates from the inner surface of the flow path 20, the velocity gradient increases, and the inner surface of the enlarged diameter portion 33 and the A vortex 45 is generated along the inner surface of the third straight pipe portion 34 and the inner surface of the straight pipe portion 66 of the connecting pipe 65 .

As a result, it is better to connect the upstream line mixer 9 and the downstream line mixer 10 via the connecting pipe 65 without connecting the connecting pipe 65 as shown in the first embodiment. Compared to the case where the line mixer 9 and the line mixer 10 on the downstream side are directly connected, a longer region in which the vortex 45 is generated can be ensured in the axial direction L (flow direction). Therefore, the raw water 2 and the flocculant 16 can be sufficiently and uniformly mixed.

FIG. 13 is a graph showing the velocity gradient distribution of the line mixer 9 having an entrance diameter of 50A, the horizontal axis representing the distance [m] from the injection port 38 of the line mixer 9 to the downstream side, and the vertical axis representing the flow rate. The average velocity gradient [1/sec] for each cross-section of path 20 is shown. The point "0" on the horizontal axis is the position of the injection port 38. As shown in FIG.

According to this, the velocity gradient is maximized at the diameter-enlarged portion 33 and gradually decreases with increasing distance from the diameter-enlarged portion 33 toward the downstream side. The velocity gradient is synonymous with stirring power, and there is a correlation that the greater the velocity gradient, the greater the stirring power, and the smaller the velocity gradient, the less the stirring power. For this reason, the stirring force is attenuated as the distance from the expanded diameter portion 33 of the line mixer 9 increases downstream, as is the case with the velocity gradient.

Therefore, in the third embodiment, the stirring force of the line mixer 10 on the downstream side becomes maximum at the enlarged diameter portion 33 before the stirring force of the line mixer 9 on the most upstream end is significantly attenuated. Stirring power lasts for a long time, so that the raw water 2 and the flocculant 16 can be sufficiently and uniformly mixed.

14 to 16 are graphs showing the distribution of velocity gradients in the line mixers 9 and 10. The horizontal axis represents the upstream end portion 33a of the enlarged diameter portion 33 of the line mixer 9 at the most upstream end (Figs. 11) to the downstream side [mm], and the vertical axis indicates the velocity gradient [1/sec] of each section of the flow path 20 . Among them, the graph G1 in FIG. 14 shows the case where only one line mixer 9 is used alone, the area of W1 on the horizontal axis corresponds to the position of the enlarged diameter portion 33 of the line mixer 9, and the arrow P It corresponds to the position of the injection port 38 of the line mixer 9 . According to this, it can be seen that the velocity gradient is maximized at the diameter-enlarged portion 33 and gradually decreases with distance from the diameter-enlarged portion 33 to the downstream side.

Graph G2 in FIG. 15 shows a case where two line mixers 9 and 10 are directly connected as in the first embodiment described above (see FIG. 3). The indicated area corresponds to the position of the enlarged diameter portion 33 of the line mixer 9 on the upstream side, the arrow P corresponds to the position of the inlet 38 of the line mixer 9 on the upstream side, and the area indicated by W2 corresponds to the line on the downstream side. It corresponds to the position of the enlarged diameter portion 33 of the mixer 10 .

Graph G3 in FIG. 16 shows a case where two line mixers 9 and 10 are connected via a connecting pipe 65 as in the third embodiment (see FIG. 11). A region indicated by W3 on the horizontal axis corresponds to the position of the connecting pipe 65 .

According to this, the stirring force of the downstream line mixer 10 becomes maximum at the enlarged diameter portion 33 before the stirring force (synonymous with the velocity gradient) of the line mixer 9 on the upstream side is significantly attenuated. It can be seen that the power lasts for a long time.

Table 3 below shows the results of examining the evaluation of the aggregation state. Among them, the condition (1) has the same form as the condition (1) in Table 2 described above. Further, the condition (3) is that the two line mixers 9 and 10 are connected via the connecting pipe 65 as in the third embodiment, and the two mixers are connected downstream of the downstream line mixer 10. It connects tanks 51 and 52 (see FIG. 2). Also, the columns of water sampling (1) and water sampling (2) are the same as in Table 2.

According to Table 3 above, the difference between the amount of residual aluminum under condition (1) and the amount of residual aluminum under condition (3) is −8.3% in water sampling (1), and the water sampling ( 2) is -10.6%. These numerical values are calculated as follows.
(0.0255−0.0278)×100/0.0278=−8.3[%]
(0.0219−0.0245)×100/0.0245=−10.6[%]
As a result, the amounts of residual aluminum in both the mixing tanks 51 and 52 are greatly reduced, so it can be seen that the agglomeration reactions are carried out well in both the mixing tanks 51 and 52, respectively. This is because the two line mixers 9 and 10 are connected via the connection pipe 65 on the upstream side of the mixing tanks 51 and 52, so that the raw water 2 and the flocculant 16 are mixed in the line mixers 9 and 10 and the connection pipe 65. is sufficiently and uniformly mixed.

Moreover, the difference between the amount of residual aluminum in the water sample (2) under the condition (1) and the residual aluminum amount in the water sample (1) under the condition (3) is 4.1%. This numerical value is calculated as follows.
(0.0255−0.0245)×100/0.0245=4.1[%]
According to this, the amount of residual aluminum in water (1) under condition (3) is almost the same as the amount of residual aluminum in water (2) under condition (1). Even if the two mixing tanks 51 and 52 are reduced to one, the amount of residual aluminum can be reduced to a value substantially equivalent to condition (1).

As a result, as shown in FIGS. 11 and 12, the upstream line mixer 9 and the downstream line mixer 10 are connected via the connecting pipe 65 with a predetermined gap, thereby coagulating the raw water 2. Since the agent 16 is sufficiently and uniformly stirred and mixed in the dissimilar liquid mixing device 4, sufficiently grown and coarsened aggregated flocs can be obtained with only one mixing tank 51, and the number of mixing tanks can be reduced. can be reduced.

In the third embodiment, as shown in FIG. 11, the connecting pipe 65 has a straight pipe portion 66 and connection flanges 67 and 68, but instead of the straight pipe portion 66, it has a curved pipe portion. You may have For example, by connecting the upstream line mixer 9 and the downstream line mixer 10 via a connecting pipe 65 having a bent pipe portion bent at 90°, the direction of the upstream line mixer 9 and the downstream side The orientation of the line mixer 10 may be orthogonal.

In the first to third embodiments, the upstream line mixer 9 and the downstream line mixer 10 have the same shape, but they may have different shapes and sizes.

(Fourth embodiment)
In the above-described third embodiment, as shown in FIG. 11, both line mixers 9 and 10 are connected using a connection pipe 65 having a straight pipe portion 66 and connection flanges 67 and 68. In the fourth embodiment described below, as shown in FIG. 17, the connection pipe 65 does not have connection flanges 67 and 68, and has only a straight pipe portion 66. As shown in FIG.

Also, the upstream line mixer 9 does not have the outlet flange 23 and the downstream line mixer 10 does not have the inlet flange 22 .

The straight pipe portion 66 of the connecting pipe 65 is integrated with the outlet side end portion of the third straight pipe portion 34 of the line mixer 9 on the upstream side and the inlet side end portion of the first straight pipe portion 30 of the line mixer 10 on the downstream side. is provided

According to this, it is possible to obtain the same actions and effects as those of the third embodiment.

In the third and fourth embodiments, as shown in FIGS. 11 and 17, two line mixers 9 and 10 are connected in series via one connecting pipe 65 with a gap therebetween. However, three or more line mixers may be connected in series via a plurality of connecting pipes 65 at intervals.

In each of the above embodiments, as shown in FIGS. 3, 11, and 17, the injection pipe 37 is connected only to the line mixer 9 on the most upstream side, and the coagulant 16 is injected only to the line mixer 9 on the most upstream side. However, the coagulant 16 may be injected by connecting the injection pipes 37 to the line mixer 9 on the most upstream side and the line mixers 10 other than the line mixer 9 respectively.

1 Water treatment facility 2 Raw water (first liquid)
4 Dissimilar liquid mixing device 5 Aggregating and mixing device 9, 10 Line mixer 16 Aggregating agent (second liquid)
20 Flow path 30 First straight pipe portion 31 Reduced diameter portion 32 Second straight pipe portion 33 Expanded diameter portion 33a Upstream end portion of expanded diameter portion 34 Third straight pipe portion 37 Injection pipe (injection route)
38 Inlet ports 51, 52 Mixing tank 65 Connection pipe A Distance from the inlet of the line mixer at the most upstream end to the upstream end of the enlarged diameter portion of the line mixer on the downstream side D Internal diameter of the third straight pipe portion d Second straight pipe Inner Diameter D' of Pipe Portion Inner Diameter Da of First Straight Pipe Portion Inner Diameter G of Straight Pipe Portion Predetermined Location L Axial Direction R Radial Direction

In order to achieve the above object, the first invention is a heterogeneous liquid mixing apparatus for injecting and mixing a second liquid into a flow path through which a first liquid flows, comprising:
Multiple line mixers are connected in series,
Each line mixer has, from the upstream side of the flow path, a second straight pipe portion, an enlarged diameter portion whose inner diameter increases toward the downstream side, and a third straight pipe portion whose inner diameter is larger than that of the second straight pipe portion. have sequentially,
the inlet at the tip of the injection path for injecting the second liquid into the first liquid projects into at least the line mixer at the most upstream end and opens;
The injection port is opened at a position corresponding to the inside of the third straight pipe portion in the axial direction of the flow path and at a position near the middle between the inner surface of the second straight pipe portion and the inner surface of the third straight pipe portion in the radial direction of the flow path. and
The inner diameter of the second straight pipe portion is d, the inner diameter of the third straight pipe portion is D, the dimension from the inlet to the inner surface of the third straight pipe portion in the radial direction of the flow path is B, and the radial direction of the flow path is Assuming that the dimension from the inlet to the inner surface of the second straight pipe portion is C,
The near-middle position is a position that satisfies 0.1×(D−d)≦B and 0.15×(D−d)≦C .

A second aspect of the present invention is a heterogeneous liquid mixing device for injecting and mixing a second liquid into a flow path in which a first liquid flows,
Multiple line mixers are connected in series,
Each line mixer has, from the upstream side of the flow path, a second straight pipe portion, an enlarged diameter portion whose inner diameter increases toward the downstream side, and a third straight pipe portion whose inner diameter is larger than that of the second straight pipe portion. have sequentially,
the inlet at the tip of the injection path for injecting the second liquid into the first liquid projects into at least the line mixer at the most upstream end and opens;
The inlet is opened at a position corresponding to the inside of the enlarged diameter portion in the axial direction of the flow path, and at a position near the middle between the inner surface of the second straight pipe portion and the inner surface of the enlarged diameter portion in the radial direction of the flow path. and
The predetermined portion of the inner surface of the enlarged diameter portion is a portion facing outward in the radial direction of the flow path from the inlet ,
Let d be the inner diameter of the second straight pipe portion, D be the inner diameter of the third straight pipe portion, and B be the dimension from the inlet in the radial direction of the flow path to a predetermined point on the inner surface of the enlarged diameter portion, and the diameter of the flow path Assuming that the dimension from the inlet in the direction to the inner surface of the second straight pipe portion is C,
The near-middle position is a position that satisfies 0.1×(D−d)≦B and 0.15×(D−d)≦C .

Claims (6)

A heterogeneous liquid mixing device for injecting and mixing a second liquid into a flow path through which a first liquid flows,
Multiple line mixers are connected in series,
Each line mixer has, from the upstream side of the flow path, a second straight pipe portion, an enlarged diameter portion whose inner diameter increases toward the downstream side, and a third straight pipe portion whose inner diameter is larger than that of the second straight pipe portion. have sequentially,
the inlet at the tip of the injection path for injecting the second liquid into the first liquid projects into at least the line mixer at the most upstream end and opens;
The injection port is opened at a position corresponding to the inside of the third straight pipe portion in the axial direction of the flow path and at a position near the middle between the inner surface of the second straight pipe portion and the inner surface of the third straight pipe portion in the radial direction of the flow path. A device for mixing different types of liquids, characterized in that: A heterogeneous liquid mixing device for injecting and mixing a second liquid into a flow path through which a first liquid flows,
Multiple line mixers are connected in series,
Each line mixer has, from the upstream side of the flow path, a second straight pipe portion, an enlarged diameter portion whose inner diameter increases toward the downstream side, and a third straight pipe portion whose inner diameter is larger than that of the second straight pipe portion. have sequentially,
the inlet at the tip of the injection path for injecting the second liquid into the first liquid projects into at least the line mixer at the most upstream end and opens;
The inlet is opened at a position corresponding to the inside of the enlarged diameter portion in the axial direction of the flow path, and at a position near the middle between the inner surface of the second straight pipe portion and the inner surface of the enlarged diameter portion in the radial direction of the flow path. and
A device for mixing different liquids, wherein the predetermined portion of the inner surface of the expanded diameter portion is a portion facing outward in the radial direction of the flow path from the injection port. Each line mixer has a first straight pipe section on the upstream side of the second straight pipe section and a reduced diameter section whose inner diameter decreases toward the downstream side in sequence,
3. The device for mixing different liquids according to claim 1, wherein the inner diameter of the first straight pipe portion is larger than the inner diameter of the second straight pipe portion. The first straight pipe portion and the third straight pipe portion have the same diameter,
4. The heterogeneous liquids according to claim 3, wherein the third straight pipe portion of the line mixer on the upstream side and the first straight pipe portion of the line mixer on the downstream side are connected via connecting pipes having the same diameter. Mixing device. 5. A line mixer according to any one of claims 1 to 4, wherein the distance from the injection port of the line mixer at the most upstream end to the upstream end of the expanded diameter portion of the line mixer on the downstream side is within 1000 mm. heterogeneous liquid mixing device. A water treatment facility comprising the device for mixing different liquids according to any one of claims 1 to 5,
the second liquid is a liquid flocculant;
the first liquid is water containing a substance to be agglomerated by the aggregating agent;
A flocculating and mixing device is connected to the downstream side of the line mixer at the most downstream end,
A water treatment facility, wherein the aggregating and mixing device has at least one mixing tank in which an upward flow path is formed between a lower inlet and an upper outlet.

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