JP7396141B2 - mixer - Google Patents

Description

The present invention relates to a mixer for mixing fluids such as liquids.

In water treatment such as wastewater and industrial water, water treatment chemicals are added to raw water, the raw water and water treatment chemicals are mixed, and then subjected to coagulation-sedimentation treatment, pressure flotation treatment, membrane filtration treatment, and treatment of equipment and piping with chemicals. It is common practice to suppress scale formation and corrosion.

Water treatment chemicals include, for example, flocculants, pH adjusters (acids, alkalis, etc.), scale inhibitors, corrosion inhibitors, and the like.

Examples of operations for mixing raw water and water treatment chemicals include a stirring tank equipped with a power unit and stirring blades, and a stationary mixer installed in piping. When injecting water treatment chemicals into raw water flowing through a pipe, it is generally injected into the side of the pipe to make processing easier and to prevent precipitates and solids from obstructing the flow and adhering to the chemical injection port. A water treatment chemical addition port will be installed in the tank.

As disclosed in Patent Documents 1 to 3, a conventional static mixer includes a cylindrical member and a twisted blade member (element) disposed within the cylindrical member.

Japanese Patent Application Publication No. 2009-106817 Japanese Patent Application Publication No. 2001-120973 Patent No. 6229185

In Patent Document 1, a plurality of units are alternately twisted 180° to the right or 180° to the left in the flow direction (the ratio of the unit length to the piping diameter is about 1.5 times), and a plurality of units are connected to divide the liquid flow. A long flow path is required for mixing. Furthermore, since a plurality of disk-shaped units with opposite twisting directions are stacked and the liquid is mixed by dividing and gathering, the structure of the disk-shaped unit is complicated. Therefore, it is unsuitable for mixing fluids with solids or precipitates. In addition, the liquid to be added to the raw water must be added to the center of the pipe, and the liquid must be added horizontally in the flow direction.

Also in Patent Documents 2 and 3, the length of the element disposed within the cylindrical member is large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a mixer that has a small size and simple structure, and does not require special measures for the position of adding liquid.

The mixer of the present invention is a mixer in which a spiral flow forming means is provided on the one end side of a cylindrical body in which fluid flows from one end to the other end (terminus), and the spiral flow forming means flows from the spiral flow forming means to the end of the cylindrical body. The ratio L/D of the length L to the inner diameter D of the cylindrical body is 3 to 5.

In one aspect of the present invention, a straight line connecting a point A on the outer periphery on the inflow side of the spiral flow forming means and a point B on the opposite side to point A on the outer periphery on the outflow side, and an axial center line of the cylindrical body. The intersection angle (helix angle) θ with the vertical plane is 1 to 30°.

In one aspect of the present invention, a ratio H/D between the length H of the spiral flow forming means in the axial direction of the cylindrical body and the diameter (inner diameter) D of the cylindrical body is 1/32 to 1/8. .

In one aspect of the present invention, the spiral flow forming means includes a plate having a spiral surface.

In one aspect of the invention, the spiral flow forming means has a two-lobed spiral surface with a central angle of 180°. Further, in one aspect of the present invention, the spiral flow forming means includes a rectangular plate, or a plate whose left side and right side of the rectangle are shaped like outwardly convex arcs, around an axis perpendicular to the upper side and the lower side. It has a twisted shape.

The mixer of the present invention generates a spiral flow within a cylindrical body using a spiral flow forming means, and mixes liquids by the generated spiral flow.

In the present invention, mixing efficiency can be improved by shallowing the helical angle θ of the helical flow forming means. As a result, liquids can be mixed with a simple and compact structure without the need for special liquid injection techniques, and the length of piping can be shortened. Moreover, since the structure of the liquid injection part can be simplified, a space-saving and simple piping mixing system is provided.

FIG. 2 is a perspective view of one end side of the mixer according to the embodiment. It is a perspective view of a mixing plate. FIG. 2 is a perspective view showing an example of a method for manufacturing a mixing plate. FIG. 2 is a cross-sectional view in the axial direction of the mixer according to the embodiment.

Hereinafter, a mixer 1 according to an embodiment will be described with reference to the drawings.

As shown in FIGS. 1 and 4, this mixer 1 includes a cylindrical body 2, a mixing plate 3 as a spiral flow forming means disposed near one end of the cylindrical body 2 in the axial direction, and In the side circumferential surface of 2, it has an inlet 4 for a mixture to be mixed, which is provided closer to the one end than the mixing plate 3. In addition, in FIG. 4, the cylindrical body 2 is shown as a cross section, and the mixing plate 3 is shown as a side view.

As shown in FIG. 3, the mixing plate 3 is constructed by chucking one side 3a and the opposite side 3b of a rectangular plate 3A, fixing the side 3a, and twisting the opposite side 3b by 180 degrees. It was formed. Note that the plate material 3A is twisted 180° around a line segment connecting the midpoints of the sides 3a and 3b. The mixing plate 3 is a spiral plate having two spiral surfaces 3f, 3f extending over a central angle of 180 degrees.

The mixing plate 3 is arranged within the cylindrical body 2 such that the axis of the spiral is coaxial with the axis of the cylindrical body 2. The outer peripheral edge of the mixing plate 3 and the inner peripheral surface of the cylindrical body 2 are fixed together by welding, brazing, adhesion, or the like.

In FIG. 4, the fluid flows from the upper end (one end) to the lower end (the other end (end)) of the cylindrical body 2, and the mixture is supplied into the cylindrical body 2 from the injection port 4. The fluid may be a liquid, gas, or slurry. The mixture may be a liquid, gas, slurry, or powder.

In FIG. 4, the length from the lower end of the mixing plate 3 to the lower end of the cylindrical body 2 is L, the axial dimension (height) of the mixing plate 3 is H, and the inner diameter of the cylindrical body 2 (mixing plate If D is the diameter of The L/D ratio is preferably 3 to 5.

In addition, in FIG. 4, a point A on the outer periphery of the inflow side (upper end side) of the mixing plate 3 and a point A on the outer periphery on the outflow side (lower end side) and on the opposite side to point A (opposite side across the axis line). The intersection angle (helix angle) θ between the straight line connecting B and the plane perpendicular to the axis of the mixing plate 3 is preferably 1 to 30 degrees, particularly 2 to 20 degrees.

In FIG. 4, the axis of the cylindrical body 2 is straight, but the axis of the cylindrical body may be curved downstream of the mixing plate 3.

Further, in the above embodiment, the mixing plate 3 is formed by twisting the plate material 3A by 180 degrees, but the twisting angle is not limited to exactly 180 degrees, and it is possible to generate a spiral flow. It is sufficient that the angle is at least 120°, preferably 150° or more. On the other hand, if the angle is too large, the burden of processing will become heavy, so the angle is set to 240° or less, preferably about 210° or less.
Further, in the above embodiment, the shape of the plate material 3A is a rectangle, but the shape is not limited to a rectangle, and the left side and right side of the rectangle may be shaped like an arc with an outward convexity, or other approximately rectangular shapes may be used. It may also be in the form of
In the present invention, a spiral flow forming means other than the mixing plate 3 may be used. For example, a rectifying member having a female screw structure and having a cylindrical outer shape may be used as the spiral flow forming means. A spiral flow can be formed by installing this rectifier in the inner circumferential wall of the pipe and passing water through it.

[Example 1]
<Experimental conditions>
In the mixer shown in Figs. 1 to 4, the inner diameter of the cylinder (mixing plate diameter) D = 150 mm, H = 18.85 mm, L = 450 mm, the thickness of the plate constituting the mixing plate 3 is 1 mm, and mixing starts from the upper end of the cylinder 2. The distance to the upper side of the plate 3 was 50 mm, the diameter of the injection port 4 was 5 mm, and the distance from the upper end of the cylindrical body 2 to the upper end of the injection port 4 was 56.925 mm.

Water at a temperature of 20°C was flowed from top to bottom at a rate of 130 m ³ /hr, and an aqueous dye solution (temperature 20°C, dye concentration 2 × 10 ^-4 g/L) was injected from the injection port 4 at a volume of 0.04 m ³ /hr. Infused at hr.

<Results/Discussion>
As a result of a computer simulation of the dye (injected liquid) distribution and the streamline distribution within the pipe under these conditions, it was found that water swirled in the cylinder 2 in a spiral manner. Furthermore, it was observed that the concentration distribution of the dye in the horizontal section at the outlet of the cylinder was extremely uniform.

[Comparative example 1]
<Experimental conditions>
A first mixing plate with a 180° right twist, where D = 150 mm and H = 225 mm, and a second mixing plate with a 180° left twist, with D = 150 mm and H = 225 mm (the twist direction in Fig. 3 is the first mixing plate). (in the opposite direction) were arranged in this order within the cylindrical body 2, one stage each. The distance from the upper end of the cylinder to the upper end of the first mixing plate was 50 mm. The experiment was conducted using the same conditions as in Example 1, such as the amount of water and the amount of aqueous dye solution injected.
As a result, the flow within the cylindrical body 2 hardly formed a spiral flow. Furthermore, it was observed that the distribution of dye concentration in the horizontal section at the exit of the cylinder was significantly non-uniform.

1 Mixer 2 Cylindrical body 3 Mixing plate 3f Spiral surface 4 Inlet

Claims (1)

A mixer in which a spiral flow forming means is provided on one end side of a cylindrical body in which fluid flows from one end to the other end (terminus),
The ratio L/D of the length L from the spiral flow forming means to the end of the cylindrical body and the inner diameter D of the cylindrical body is 3 to 5,
An intersection angle θ between a straight line connecting a point A on the outer peripheral edge on the inflow side of the spiral flow forming means and a point B on the opposite side to point A on the outer peripheral edge on the outflow side and a plane perpendicular to the axis of the cylindrical body. is 1 to 30°,
The ratio H/D of the length H of the spiral flow forming means in the axial direction of the cylindrical body and the diameter (inner diameter) D of the cylindrical body is 1/32 to 1/8,
The spiral flow forming means is composed of a plate having a spiral surface,
The spiral flow forming means has a shape in which a rectangular plate or a plate with the left and right sides of the rectangle in an outwardly convex arc shape is twisted by 120 to 240 degrees around an axis perpendicular to the upper and lower sides,
A fluid inlet is provided between the one end side of the side peripheral surface of the cylindrical body and the spiral flow forming means.
mixer.

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