Gas mixer

Abstract

To provide a gas mixer that can reduce occurrence of resistance and mix two kinds of fluid with each other appropriately.SOLUTION: A gas mixer 100 comprises: a supply pipe 110 connected to a side surface of main piping 200; the main piping 200 which comprises a cylindrical main body part 121 having a diameter smaller than a diameter of the main piping 200 and a plurality of toric wall parts 123 and 124 protruding from an outer surface of the main body part 121 to contact an inner surface of the main piping 200, where the plurality of wall parts 123 and 124 respectively comprises notches 125 and 126 at positions different from each other; a dispersion part 120 fitted to inside of the main piping 200 so that at least a portion thereof overlaps with a connection part at which the main piping is connected to the supply pipe 110; a supply ring 130, arranged at a downstream side of the dispersion part 120, which is a cylindrical member having a diameter smaller than a diameter of the main piping 200 comprising a plurality of through-holes 131 formed to extend in a radial direction; and a sealing ring 140 arranged at a downstream side of the supply ring 130 and fitted to inside of the main piping 200.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas mixer.

Background Art

[0002] Patent Document 1 describes a stationary gas mixer for mixing components of exhaust gas of an internal combustion engine with a reducing agent. Specifically, the stationary gas mixer described in Patent Document 1 includes at least two baffle plates disposed one behind the other in the direction of the flow of the components of the mixture within a housing. Further, the holes of the preceding baffle plate are located in one half on one side of the baffle plate, while the holes of the subsequent baffle plate are located in the other half on the other side of the baffle plate. Thereby, a turbulent flow is generated in the mixture flowing inside the housing, and it is intended that the mixture is preferably mixed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, there is a problem that a large resistance occurs because the mixture collides with the baffle plate.

[0005] The present invention has been made to solve such a problem, and an object thereof is to provide a gas mixer that can reduce the generation of resistance and preferably mix two fluids.

Means for Solving the Problems

[0006] A gas mixer according to a first aspect of the present invention is a gas mixer for mixing a main fluid and a fluid to be mixed in a main pipe, comprising: a supply pipe connected to the side surface of the main pipe; a cylindrical body having a diameter smaller than the diameter of the main pipe; a plurality of annular wall portions protruding from the outer surface of the body portion and contacting the inner surface of the main pipe; a distribution portion fitted inside the main pipe such that at least a portion overlaps with a connecting portion connecting the main pipe and the supply pipe, wherein the plurality of wall portions have notches at different positions from each other; a supply ring, a cylindrical member having a diameter smaller than the diameter of the main pipe and having a plurality of through holes extending in the radial direction, disposed inside the main pipe downstream of the distribution portion; and a sealing ring disposed downstream of the supply ring and fitted inside the main pipe. [Effects of the Invention]

[0007] According to the first aspect of the present invention, the fluid to be mixed supplied from the supply pipe is dispersed in the space between the dispersion section and the main pipe, and the dispersed fluid to be mixed is supplied into the interior of the supply ring through a plurality of through holes in the supply ring and mixed with the main fluid. The fluid to be mixed flows into the main fluid from a plurality of directions along the direction intersecting the direction in which the main body flows, through the plurality of through holes in the supply ring. Therefore, the main fluid and the fluid to be mixed can be suitably mixed without arranging a baffle plate inside the main pipe. Thus, it is possible to provide a gas mixer that reduces the generation of resistance and can suitably mix the two fluids. [Brief explanation of the drawing]

[0008] [Figure 1] This is a partial cross-sectional view showing an example of a gas mixer according to Embodiment 1 of the present invention. [Figure 2] This is a perspective view showing an example of a gas mixer according to Embodiment 1 of the present invention. [Figure 3] This is a cross-sectional view along the line III-III in Figure 2. [Modes for carrying out the invention]

[0009] Embodiment 1 of the present invention will be described below with reference to the drawings. However, the present invention is not limited to Embodiment 1 below. Also, for clarity of explanation, the following description and drawings have been simplified as appropriate.

[0010] (First embodiment) The gas mixer 100 according to the first embodiment will be described below with reference to Figure 1. Figure 1 is a partial cross-sectional view of the gas mixer 100. Specifically, in Figure 1, the main piping 200 and the supply pipe 110 are shown in cross-sectional views, and the rest of the gas mixer 100 is shown in a side view. In Figure 1, the flow of the main fluid flowing through the main piping 200 is indicated by hatched arrows, and the flow of the fluid to be mixed is indicated by white arrows. The right-handed XYZ Cartesian coordinate system shown in Figure 1 and other drawings is for convenience in explaining the positional relationships of the components. The Z-axis+ direction is vertically upward, the XY plane is the horizontal plane, and the X-axis+ direction is the axial direction of the main piping 200, moving from upstream to downstream, and this is common to all drawings. Figure 2 is a perspective view of the gas mixer 100. In Figure 2, the main piping 200 and the supply pipe 110 are shown by dashed lines, and the rest of the gas mixer 100 is shown by solid lines. In Figure 2, the flow of the fluid to be mixed is indicated by black arrows. Figure 3 is a cross-sectional view along the line III-III in Figure 2.

[0011] As shown in Figures 1 to 3, the gas mixer 100 comprises a supply pipe 110, a dispersion section 120, a supply ring 130, and a sealing ring 140. The supply pipe 110, dispersion section 120, supply ring 130, and sealing ring 140 are formed using, for example, stainless used steel (SUS). However, the material of the supply pipe 110, dispersion section 120, supply ring 130, and sealing ring 140 may be changed depending on the chemical properties of the main fluid and the fluid to be mixed by the gas mixer 100.

[0012] The supply pipe 110 is connected to the side of the main pipe 200. Specifically, the supply pipe 110 is connected to the side of the main pipe 200 such that the axial direction (X-axis direction) of the main pipe 200 intersects with the axial direction of the supply pipe 110. The main pipe 200 is the pipe through which the main fluid flows. The supply pipe 110 is the pipe that supplies the fluid to be mixed, with a flow rate lower than that of the main fluid. For example, the main fluid is a fluid containing components of exhaust gas from an internal combustion engine, and the fluid to be mixed is a fluid containing a reducing agent.

[0013] As shown in Figures 1 and 2, the distribution section 120 is fitted inside the main pipe 200 such that, in the X-axis direction, at least a portion of it overlaps with the connecting section where the main pipe 200 and the supply pipe 110 are connected. The distribution section 120 also comprises a main body section 121, a first wall section 122, a second wall section 123, and a third wall section 124.

[0014] The main body 121 is a cylindrical member having a diameter smaller than the diameter of the main pipe 200. The inside of the cylinder of the main body 121 is in communication with the inside of the main pipe 200, and the main body flowing through the main pipe 200 flows into the inside of the main body 121.

[0015] The first wall portion 122 is an annular wall that protrudes radially from the upstream end of the outer surface of the main body portion 121 and abuts against the inner surface of the main pipe 200. The first wall portion 122 is located upstream of the connection portion where the main pipe 200 and the supply pipe 110 are connected. The first wall portion 122 prevents the main body from flowing into the space between the connection portion where the main pipe 200 and the supply pipe 110 are connected and the outer surface of the main body portion 121. The main body that is blocked by the first wall portion 122 flows into the interior of the main body portion 121. The inner surface of the main body portion 121 corresponding to the first wall portion 122 may be inclined so that the diameter gradually decreases from upstream to downstream (towards the X-axis + direction), as shown by the dashed line in Figure 1. This reduces the resistance caused by the main body being blocked by the first wall portion 122.

[0016] The second wall portion 123 is a substantially annular wall that protrudes radially from the downstream side of the first wall portion 122 on the outer surface of the main body portion 121 and abuts against the inner surface of the main pipe. The second wall portion 123 is located downstream of the connection portion where the main pipe 200 and the supply pipe 110 are connected. The second wall portion 123 also has a plurality of notches 125 cut out in the X-axis direction. In the example shown in Figures 1 and 2, two notches 125 are formed at a position 90° circumferentially away from the connection portion between the main pipe 200 and the supply pipe 110. The number, width, and position of the notches 125 may be changed depending on the viscosity, density, flow rate, etc. of the fluid to be mixed.

[0017] The third wall portion 124 is an annular wall that protrudes radially from the downstream end of the main body portion 121 and abuts against the inner surface of the main pipe 200. The third wall portion 124 also has a plurality of notches 126 cut out in the X-axis direction. In the example shown in Figures 1 to 3, six notches 126 are formed at 60° intervals in the circumferential direction, with the position of the connection between the main pipe 200 and the supply pipe 110 being 0°. The number, width, and position of the notches 126 may be changed depending on the viscosity, density, flow rate, etc. of the fluid to be mixed.

[0018] Furthermore, the circumferential position where the notch 125 is provided in the second wall portion 123 is different from the circumferential position where the notch 126 is provided in the third wall portion 124. As a result, the fluid to be mixed that flows from the supply pipe 110 into the space between the inner surface of the main pipe 200 and the outer surface of the main body portion 121 flows along the outer surface of the main body portion 121, passes through the notch 125, then flows further along the outer surface of the main body portion 121, passes through the notch 126, and moves to the downstream side of the distribution portion 120. Therefore, the fluid to be mixed supplied from the supply pipe 110 is distributed throughout the main pipe 200, along the inner surface of the main pipe 200.

[0019] In the examples shown in FIGS. 1 and 2, an example is shown in which the dispersion part 120 includes two wall parts 123 and 124 having cutouts 125 and 126. However, the number of wall parts 123 and 124 included in the dispersion part 120 is not limited as long as it is two or more. The number of wall parts 123 and 124 included in the dispersion part 120 may be changed according to the viscosity, density, and flow rate of the fluid to be mixed.

[0020] The supply ring 130 is disposed inside the main pipe 200 and on the downstream side of the dispersion part 120. The supply ring 130 is a cylindrical member having a diameter smaller than the diameter of the main pipe 200. The inside of the supply ring 130 communicates with the inside of the cylinder of the dispersion part 120, and the main fluid flowing through the inside of the dispersion part 120 flows into the inside of the supply ring 130. In the examples shown in FIGS. 1 to 3, the supply ring 130 is a cylindrical member having an octagonal outer shape and a circular inner shape in a cross section parallel to the Y-Z plane (see FIG. 3). The supply ring 130 includes a plurality of through holes 131 provided to extend in the radial direction. In the examples shown in FIGS. 1 to 3, a total of eight through holes 131 are provided one by one from each side of the octagon toward the inside in the radial direction. Thereby, the fluid to be mixed that has flowed into the space between the inner surface of the main pipe 200 and the outer surface of the supply ring 130 through the cutout 126 of the third wall part 124 flows into the inside of the supply ring 130 through the through holes 131 and is mixed with the main fluid. The fluid to be mixed flows into the main fluid from a plurality of directions along a direction intersecting the direction in which the main fluid flows through the plurality of through holes 131 of the supply ring 130. Therefore, the main fluid and the fluid to be mixed can be suitably mixed without arranging a baffle plate inside the main pipe 200. Thereby, the distance of the flow path of the main pipe 200 required for mixing the main fluid and the fluid to be mixed can be shortened, and the main pipe 200 can be made compact. Note that the number and diameter size of the through holes 131 may be changed according to the ratio between the flow rate of the main fluid and the flow rate of the fluid to be mixed. Also, the outer shape of the supply ring 130 is not limited to an octagon.

[0021] In the example shown in FIGS. 1 to 3, the through hole 131 is provided at a position displaced (separated) in the circumferential direction from a radial axis (indicated by a dashed-dotted line in FIG. 3) that intersects the axis of the main pipe 200 (an axis parallel to the X axis). As a result, an eddy current is formed in the direction indicated by the solid arrow in FIG. 3 by the fluid to be mixed that has flowed into the inside of the supply ring 130 through the through hole 131. Therefore, due to the eddy current, the interface between the main fluid and the fluid to be mixed is easily disturbed, and furthermore, the distance of the flow path of the main pipe 200 required to mix the main fluid and the fluid to be mixed can be shortened.

[0022] The sealing ring 140 is disposed inside the main pipe 200 on the downstream side of the supply ring 130 and is fitted inside the main pipe 200. The sealing ring 140 seals the space between the inner surface of the main pipe 200 and the outer surface of the supply ring 130. Thereby, the sealing ring 140 prevents the fluid to be mixed from being mixed into the main fluid without passing through the through hole 131. Further, the inside of the sealing ring 140 communicates with the inside of the supply ring 130, and the main fluid in which the fluid to be mixed flowing through the inside of the supply ring 130 is mixed flows into the inside of the sealing ring 140.

[0023] Next, the assembly of the gas mixer 100 will be described. First, the dispersion part 120, the supply ring 130, and the sealing ring 140 are joined by welding or the like. Next, a through hole for communicating with the supply pipe 110 is provided on the side surface of the main pipe 200 cut to a length that can enclose the joined dispersion part 120, supply ring 130, and sealing ring 140, and the supply pipe 110 is joined by welding or the like at the position of the through hole. Next, the joined dispersion part 120, supply ring 130, and sealing ring 140 are fitted inside the main pipe 200 and fixed by welding or the like. Next, the main pipe 200 in which the dispersion part 120, supply ring 130, and sealing ring 140 are fitted is joined to another main pipe 200 by welding or the like. In addition, when the main pipe 200 is provided with a flange, the joining of the main pipe 200 in which the dispersion part 120, supply ring 130, and sealing ring 140 are fitted and another main pipe 200 may be realized by joining the flanges of the two main pipes using bolts or the like.

[0024] As described above, in the gas mixer 100 according to the first embodiment, the fluid to be mixed supplied from the supply pipe 110 is dispersed in the space between the dispersion section 120 and the main pipe 200, and the dispersed fluid to be mixed is supplied into the inside of the supply ring 130 through a plurality of through holes 131 of the supply ring 130 and mixed with the main fluid. The fluid to be mixed flows into the main fluid from a plurality of directions along the direction intersecting the direction in which the main body flows, through the plurality of through holes 131 of the supply ring 130. Therefore, the main fluid and the fluid to be mixed can be suitably mixed without arranging a baffle plate inside the main pipe 200. Thus, a gas mixer 100 can be provided that reduces the generation of resistance and can suitably mix the two fluids.

[0025] Specifically, the greater the difference between the flow rate of the main fluid and the flow rate of the fluid to be mixed, the less likely it is that simply supplying the fluid to be mixed from the supply pipe 110 connected to the main pipe 200 into the main pipe 200 will create turbulence at the interface between the main fluid and the fluid to be mixed, resulting in uneven and uniform mixing. Furthermore, if a baffle plate is placed inside the main pipe 200, resistance will be generated as the fluid collides with the baffle plate. Another possible method is to create vortices in the fluid flowing inside the main pipe 200 by installing blades inside the main pipe 200. However, in this case, since both the main fluid and the fluid to be mixed form vortices, the interface between the main fluid and the fluid to be mixed remains intact while the vortices are formed. Therefore, a long flow path is required to completely mix the main fluid and the fluid to be mixed. Moreover, the fabrication of the blades requires complex processing techniques, and special welding techniques are needed to attach the blades inside the main pipe 200.

[0026] In contrast, in the gas mixer 100 according to this embodiment 1, the fluid to be mixed, dispersed in the space between the dispersion unit 120 and the main pipe 200, flows into the main fluid from multiple directions along the direction intersecting the direction in which the main body flows, through multiple through holes 131 in the supply ring 130. Therefore, the main fluid and the fluid to be mixed can be suitably mixed without arranging baffle plates or blades inside the main pipe 200. Furthermore, the dispersion unit 120, the supply ring 130 and the sealing ring 140 can be manufactured by machining using a lathe, and the gas mixer 100 can be installed in the main pipe 200 by the simple assembly process described above. Therefore, the gas mixer 100 can be installed in the main pipe 200 without requiring special processing or welding techniques.

[0027] Furthermore, the through-hole 131 is positioned circumferentially offset (spaced) from the radial axis (shown as a dashed line in Figure 3) that intersects the axis of the main pipe 200 (the axis parallel to the X-axis). This makes the interface between the main fluid and the fluid to be mixed more turbulent due to the vortex flow formed by the fluid to be mixed that flows into the inside of the supply ring 130 through the through-hole 131, and further shortens the distance of the flow path in the main pipe 200 required to mix the main fluid and the fluid to be mixed. In fact, when mixing a fluid to be mixed with a flow rate of 24 liters / min into a main body with a flow rate of 1700 liters / min using the gas mixer 100, CAE analysis of the distribution of the fluid to be mixed at a position 150 mm downstream from the supply pipe 110 confirmed that the fluid to be mixed was uniformly distributed relative to the main fluid.

[0028] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, the gas mixer 100 can also be used when mixing hydrogen gas with air in a hydrogen engine. [Explanation of symbols]

[0029] 100 Gas Mixer 110 Supply pipe 120 Dispersion section 121 Main body 122 First wall section 123 Second Wall Section 124 Third Wall 125,126 notches 130 supply rings 131 Through hole 140 sealing rings

Claims

[Claim 1] A gas mixer that mixes a main fluid and a fluid to be mixed in the main pipe, A supply pipe connected to the side of the main piping, A distribution part fitted inside the main pipe, comprising a cylindrical body having a diameter smaller than the diameter of the main pipe, and a plurality of annular wall portions protruding from the outer surface of the body and contacting the inner surface of the main pipe, wherein the plurality of wall portions have notches at different positions from each other, and the distribution part overlaps at least a portion with the connecting part to which the main pipe and the supply pipe are connected, A supply ring is provided, which is a cylindrical member located inside the main pipe and downstream of the distribution section, having a diameter smaller than the diameter of the main pipe, and having a plurality of through holes extending in the radial direction, A sealing ring is positioned downstream of the supply ring and fitted inside the main piping, Equipped with, Gas mixer.

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