Fluidic mixer

Abstract

The invention relates to a fluidic mixer comprising: an outer supply pipe; an inner supply pipe inserted into the outer supply pipe and extending downstream in overlap with the outer supply pipe to an inner supply pipe outlet, the outer supply pipe having a pipe diameter constriction downstream of the insertion position of the inner supply pipe, the outer supply pipe smoothly transitioning from upstream and downstream to the pipe diameter constriction, a radial gap existing between the inner supply pipe and the outer supply pipe throughout the region of overlap due to the difference in pipe diameter; a section of the inner supply pipe upstream from the inner supply pipe outlet having a number of radial inward recesses, the radial inner edges of each radial inward recess extending to the inner supply pipe outlet and tapering in the direction towards the inner supply pipe outlet but still not contacting each other at the inner supply pipe outlet.

Description

Technical Field

[0001] This invention relates to a jet mixer. Background Technology

[0002] In the waste paper pulping industry, it is usually necessary to dilute the pulp with white water. Generally, this dilution can be carried out pre-pump by thorough mixing on the inlet line of the pulp supply pump. The rotor of the pulp supply pump is capable of thoroughly mixing two or more streams of fluid; in this case, the pulp supply pump is, for example, the flushing pump of the paper machine flow rate system. Taking a low-consistency desander as an example, the thick pulp line is inserted between the white water tank and the pulp supply pump. After the thick pulp is mixed with the white water, the concentration at all points on the cross-section of the pipe is uniform after the pump outlet due to the stirring action of the pump impeller.

[0003] Alternatively, in pipeline dilution where thorough mixing is not required: the slurry flows from the outlet of equipment A to the inlet of equipment B. If dilution is needed before entering equipment B, dilution water can be added directly to the pipeline between the two equipments. Water suspensions containing different concentrations or different media components will be uniformly mixed in the subsequent equipment B (such as a slurry screener) which has a stirring function. If one outlet of equipment A flows into equipment B, another outlet into equipment C, or into more equipment, and it is necessary to ensure that the proportion of dilution water added before entering these equipments is the same, ensuring the same concentration in multiple equipments such as B / C, flow control is typically used to control the dilution water flow rate to each equipment and the ratio of the flow rate from the outlet of equipment A to each equipment.

[0004] In this type of pipeline dilution process, if the outlet pressure of equipment A flows to equipment B, due to the friction between the fluid itself or the pipe wall, a certain amount of energy will inevitably be lost, which is usually manifested as pressure attenuation. If the pressure is not attenuated or is increased to meet the minimum working pressure requirement of equipment B, it is usually done according to the principle of a jet pump. That is, high-pressure dilution water is used to form a high-velocity dilution water flow, which flows in (injects) at a high velocity along the direction of the diluted slurry. The high-velocity dilution water brings more kinetic energy. When it encounters the diluted slurry with a lower velocity, the velocity of the dilution water decreases, and the velocity energy is converted into pressure energy (that is, according to Bernoulli's equation, white water first converts pressure energy into velocity energy, and after flowing into the concentrated slurry, the velocity energy is converted back into pressure energy).

[0005] In other words, the existing jet pump uses a motive fluid with a high flow rate or jet velocity to accelerate a slow-flowing or stationary transported fluid. As the accelerated fluid gradually decreases in velocity within a pipeline with an increasing diameter, the decrease in fluid velocity head also causes the pressure head to rise.

[0006] However, when the slurry and water meet in the pipeline, it cannot be guaranteed that the concentration is uniform at all points across the cross-section of the pipeline; only that the water-to-slurry ratio is stable over time. Therefore, existing jet pumps are only used for dilution and not as a means to achieve thorough mixing.

[0007] Here, "thorough mixing" means that the concentration difference at various points on the cross-section of the pipeline is ±5%, and at most no more than ±10%.

[0008] If the B equipment following the outlet of equipment A is a low-concentration desander or a light-weight slag remover, then the B equipment's desander typically consists of dozens or even hundreds of suspension separation units. The slurry enters from the main pipe, then flows through the branch pipes of the desander unit. If the concentrated slurry and dilution water from equipment A are not sufficiently mixed in the main pipe, resulting in uneven concentration along the pipe diameter, the concentration entering the downstream parallel equipment will vary after passing through the branch pipes. For example, if the downstream equipment is a desander, and the slurry concentration reaching these parallel desander units is uneven, even if only a few desander units have excessively high inlet concentrations and fail to separate, the overall efficiency of the desander will be significantly reduced.

[0009] It is important to clarify that when the slurry pipeline is connected between the white water tank and the slurry supply pump using a simple tee connection, the pressure of the slurry does not act on the slurry supply pump; it is essentially released. The slurry supply pump then draws in almost static white water and slurry for repressurization. When adding dilution water to the slurry using a jet pump, the problem of poor online dilution and mixing uniformity arises, as mentioned above. Furthermore, using resistance elements such as orifice plates or baffles in the flow channel to achieve better mixing results in a significant pressure drop, i.e., liquid energy consumption.

[0010] Therefore, it is desirable to provide a jet mixer that can achieve smooth mixing while diluting the slurry with dilution water. Summary of the Invention

[0011] To address the above technical problems, the present invention provides a jet mixer comprising: an outer supply pipe; and an inner supply pipe, wherein the inner supply pipe is inserted into the outer supply pipe and extends downstream overlapping with the outer supply pipe to the outlet of the inner supply pipe, the outer supply pipe having a diameter narrowing section downstream of the insertion position of the inner supply pipe, the outer supply pipe smoothly transitioning from upstream to downstream to the diameter narrowing section, wherein the inner supply pipe and the outer supply pipe always have a radial gap in the overlapping extension area due to the difference in pipe diameter; wherein a section of the inner supply pipe extending upstream from the outlet of the inner supply pipe has a plurality of radially concave portions, wherein the radially inner edge of each radially concave portion extends to the outlet of the inner supply pipe and gradually narrows in the direction toward the outlet of the inner supply pipe but does not contact each other at the outlet of the inner supply pipe.

[0012] The radial inner edges of each radial concave portion do not contact each other at the outlet of the inner supply pipe in order to avoid large impurities from bridging and clogging.

[0013] The radial concavity of the inner supply pipe smoothly transitions its cross-sectional shape from a circle to a "petal" shape, resulting in a larger contact boundary between the fluid inside and outside the inner supply pipe upon reaching the outlet. The inner and outer flow channels formed by this radial concavity effectively reduce the lateral dimensions of the flow cross-sections inside and outside the inner supply pipe. This means that before mixing begins at the outlet, the Reynolds numbers of both fluids are lower than those inside and outside the circular nozzle. Therefore, the two fluids are less likely to enter a turbulent state before mixing, resulting in smoother flow and lower resistance. Due to the longer contact boundary and the intersection of the two fluids, uniform mixing can be achieved without strong turbulent disturbances or a large velocity difference between them upon meeting.

[0014] The radial concave portion of the inner flow tube is made as long as possible in the flow direction so that the inner flow tube can smoothly transition from a circular pipe to a petal-like cross-section. The length of this transition region, also known as the jet acceleration zone, is usually three times or more the diameter of the inner flow tube.

[0015] Typically, the fluid in the inner supply pipe enters the jet acceleration zone defined by the radial concave section at a normal pipeline flow rate of 1 m / s to 5 m / s, and the two fluids begin to contact at the outlet of the inner supply pipe. The mixed fluid reaches its highest average velocity at the narrowing section of the outer supply pipe.

[0016] If the goal is simply to mix the two fluids uniformly over a short distance, the flow velocity at the outlet of the internal flow supply pipe can be as low as 4 m / s to 8 m / s. At this point, the mixed fluid can achieve a relatively low flow velocity of 4 m / s at the narrowing section of the pipe.

[0017] If it is necessary to dilute the fluid and increase the pressure of the diluted fluid at the same time, a stronger jet pump effect can be achieved by providing a higher pressure fluid in the inner supply pipe. Depending on the pressure increase requirement, the fluid velocity in the radial concave section should be between 10 m / s and 30 m / s. This will accelerate the flow velocity of the fluid outside the inner supply pipe with the pressure of the fluid in the inner supply pipe. The mixed fluid passes through the narrowed section of the pipe at a higher speed. The outer supply pipe gradually increases in diameter downstream of the narrowed section, causing the fluid to gradually decelerate and increase the pressure.

[0018] In the jet mixer of the present invention, a radial gap is left between the inner and outer supply pipes to allow flow. A first fluid, such as slurry, flows through the periphery of the inner supply pipe, and a second fluid, such as dilution water under certain pressure, flows through the inside of the inner supply pipe. The two fluids mix at the outlet of the inner supply pipe.

[0019] Because the jet mixer has several radially recessed sections within the pipe section near the outlet of the inner supply pipe, with the inner radial edge of each recess extending to the outlet of the inner supply pipe and remaining separate at the outlet, it effectively forms a petal-like shape. This shape provides a wider area of ​​dispersed jetting and a contact interface that allows the two fluids to fully contact, compared to existing jet pumps that concentrate the jetting only near the center. The radially recessed sections not only increase the area of ​​the inner supply pipe outlet relative to the central region of the existing jet pump outlet (due to the increased area connecting the radially recessed sections to the center of the outlet), but also significantly increase the contact area for mixing the two fluids because the perimeter of the radially recessed sections is much larger relative to the central region of the jet pump outlet. Furthermore, because the radially recessed sections themselves form grooves of gradually varying depths relative to the fluid outside the inner supply pipe, and the area between the radially recessed sections relative to the fluid inside the inner supply pipe, the Reynolds number decreases exponentially when the fluid flows within these grooves. Therefore, the two fluids can avoid turbulence and energy consumption before mixing.

[0020] Since thorough mixing of the two fluids can be achieved near the outlet of the inner supply pipe of the jet mixer, the desired slurry dilution concentration can be achieved by quantitatively supplying dilution water, and the pressure of the diluted and mixed slurry can be controlled relatively precisely by appropriately setting the pressure of the dilution water. Particularly advantageous is that, in the jet mixer of this invention, since there are no resistance elements such as orifice plates or baffles in the flow channel, nor are there moving parts such as pump impellers, the pressure supplied upstream can be supplied downstream with low loss. This is particularly significant when it is desirable to utilize the liquid energy of upstream equipment, such as a pressure screen.

[0021] Moreover, when the slurry concentration at the outlet of the pressure screen is higher than the required concentration at the inlet of the desander, the concentrations of the two can be easily matched by dilution and mixing through a jet mixer, so as to minimize the loss of liquid energy.

[0022] The number of radially recessed sections is preferably 3 to 8, and typically 6. When the internal supply pipe has a high injection velocity, and it is desired that the pressure after mixing is more than 50 kP higher than before dilution, it is necessary to mix the two fluid streams under a large velocity difference. In this case, a 3-lobed nozzle is a better choice. When it is desired to emphasize uniform dilution without a significant need to increase pressure, a design with a larger number of radially recessed sections can be used.

[0023] Based on similar considerations, the position of the inner supply pipe outlet relative to the pipe diameter narrowing section can be designed accordingly. The greater the velocity difference between the fluids inside and outside the inner supply pipe, the better the mixing effect of the two fluids. The pipe diameter narrowing section reduces the flow cross-section of the fluid outside the inner supply pipe, thus causing the velocity head of the fluid (e.g., slurry) outside the inner supply pipe to become a pressure head. In other words, the fluid outside the inner supply pipe will be decelerated due to the pipe diameter narrowing section. Therefore, in order to have a large velocity difference when the two fluids meet, the outlet of the inner supply pipe should be located 1.5 to 4 times the pipe diameter of the narrowing section before the pipe diameter narrowing section. If dilution only requires good mixing, then the dilution water does not necessarily need to have a high pressure. In this case, it is not necessary to create a large fluid velocity difference between the inside and outside of the inner supply pipe. Therefore, in an alternative embodiment of the jet mixer according to the present invention, the outlet of the inner supply pipe can be located at the pipe diameter narrowing section, or even enter the pipe diameter narrowing section if the pipe diameter relationship between the pipe diameter narrowing section and the outlet of the inner supply pipe allows. That is to say, the outlet of the inner supply pipe can even be located downstream of the pipe diameter narrowing section.

[0024] In the tapered section transitioning upstream from the narrowing section to the outer supply pipe diameter, a length ratio of the tapered section to the outer supply pipe diameter of less than 7 times will cause excessive deceleration, resulting in eddies during the flow velocity reduction process (a small amount of reverse flow was observed in the simulation). These eddies can lead to fluid energy loss or pipe wear. Therefore, it is preferable that the outlet of the inner supply pipe is located at a distance of 9 times the outer supply pipe diameter upstream of the narrowing section.

[0025] Although the radial inner edge of each radial recess gradually contracts in the direction toward the outlet of the inner flow tube as it extends toward the outlet of the inner flow tube, it is easy to understand that this does not restrict the trend of change of the outer edge envelope of the inner flow tube.

[0026] In a preferred embodiment of the jet mixer according to the invention, the section of the inner supply pipe with a radially concave portion has an outer edge envelope that gradually tapers toward the outlet of the inner supply pipe. However, alternatively or additionally, the section of the inner supply pipe with a radially concave portion may also have an outer edge envelope that gradually increases toward the outlet of the inner supply pipe, or the outer edge envelope of the section of the inner supply pipe with a radially concave portion may have a constant diameter.

[0027] In a preferred embodiment of the jet mixer according to the invention, the radially inner edge of the inner supply pipe outlet protrudes further downstream in the axial direction than the radially outer edge. However, as an alternative or supplementary measure, it is also possible that the radially outer edge of the inner supply pipe outlet is flush with the radially inner edge in the axial direction. Alternatively, the radially outer edge of the inner supply pipe outlet can be designed to protrude further downstream in the axial direction than the radially inner edge. When the radially outer edge of the inner supply pipe outlet protrudes downstream or upstream compared to the radially inner edge, that is, the inner supply pipe outlet can be a convex or concave shape, such a shape can further increase the contact boundary between the two fluids.

[0028] Similarly, each of the radial recesses has the same starting position upstream of the jet mixer outlet. Alternatively or supplementarily, each of the radial recesses may also have a different starting position upstream of the jet mixer outlet. Alternatively, several sets of radial recesses with different starting positions may be arranged in a mixed or alternating manner in the circumferential direction.

[0029] In a preferred embodiment of the jet mixer according to the invention, each radially recessed portion of the inner supply tube has the same width in the radial direction. Alternatively, each radially recessed portion may be designed to have a width that gradually expands radially from the inside out or a width that gradually narrows radially from the inside out. Thus, each petal of the "petal"-shaped cross-section of the inner supply tube can have a correspondingly different shape, thereby enabling smaller or larger contact boundaries for the inner and outer fluid streams.

[0030] The jet mixer can adopt the structure of a conventional jet pump, that is, the outer supply pipe of the jet mixer has a bend while the inner supply pipe is straight. Downstream of the position where the inner supply pipe extends into the outer supply pipe, the outer supply pipe transitions through the bend of the outer supply pipe to extend downstream and overlap with the inner supply pipe.

[0031] Alternatively, the jet mixer can be designed such that the outer supply pipe is straight while the inner supply pipe has a bend, wherein downstream of where the inner supply pipe extends into the outer supply pipe, the inner supply pipe transitions through the bend to extend downstream and overlap with the outer supply pipe.

[0032] Alternatively, a technical solution could be considered in which the first supply pipe of the jet mixer is straight, and the second supply pipe, after extending into the first supply pipe, transitions downstream through the bend of the jet mixer to extend coaxially with the first supply pipe.

[0033] Optionally, the inner supply pipe is used to supply the first fluid while the outer supply pipe is used to supply the second fluid, or the inner supply pipe is used to supply the second fluid while the outer supply pipe is used to supply the first fluid. For example, if the first fluid is a diluted slurry and the second fluid is dilution water, the slurry can be supplied either in the outer supply pipe or the inner supply pipe. Attached Figure Description

[0034] The present invention will now be described in detail with reference to the accompanying drawings. In the drawings:

[0035] Figure 1 A perspective view schematically illustrating one embodiment of the jet mixer of the present invention is shown.

[0036] Figure 2 A perspective view schematically illustrates another embodiment of the jet mixer of the present invention;

[0037] Figure 3 A schematic cross-sectional view of the radially recessed portion of the jet mixer of the present invention is shown;

[0038] Figure 4 A perspective view of the inner flow supply pipe of the jet mixer of the present invention is shown schematically;

[0039] Figure 5 A perspective view of the inner supply pipe of the jet mixer of the present invention is schematically shown, wherein it has a... Figure 4 Different numbers of radial indentations;

[0040] Figure 6 A perspective view of the internal flow supply pipe of the jet mixer of the present invention is schematically shown, wherein it has a... Figure 4 and Figure 5 Different numbers of radial indentations;

[0041] Figure 7 A perspective view of the inner flow supply pipe of the jet mixer of the present invention is shown schematically;

[0042] Figure 8A This is a perspective view of the jet mixer of the present invention;

[0043] Figure 8B This is a simulation diagram of the temperature distribution when two fluids at different temperatures flow through the jet mixer of this invention;

[0044] Figure 8C Further shown Figure 8B The simulated temperature data of the jet mixer at the inlet of each desander unit is shown.

[0045] Figure 9A The pipeline structure for mixing two fluids via a three-way valve before a desander is shown in the prior art;

[0046] Figure 9B It shows the flow of fluids at two different temperatures. Figure 9A The simulation diagram of the temperature distribution of the pipeline structure shown in the figure, especially the temperature distribution data at the inlet of the desander unit;

[0047] Figure 10A This illustrates an alternative pipeline structure for mixing two fluids via a T-junction before a desander, according to existing technology.

[0048] Figure 10B It shows the flow of fluids at two different temperatures. Figure 10A Simulation diagram of temperature distribution of the pipeline structure shown;

[0049] Figure 11A A perspective view of a jet pump is schematically shown;

[0050] Figure 11B schematically shown Figure 11A The diagram shows the pipeline structure connecting the jet pump to the desander.

[0051] Figure 11C It shows the flow of fluids at two different temperatures. Figure 11B The simulation diagram of the temperature distribution of the pipeline structure shown in the figure, especially the temperature distribution data at the inlet of the desander unit;

[0052] Figure 12 A perspective view schematically illustrates another embodiment of the jet mixer of the present invention; Detailed Implementation

[0053] Figure 1 A perspective view of a first embodiment of the jet mixer of the present invention is schematically shown. An inner supply pipe is inserted into an outer supply pipe and extends downstream, overlapping with the outer supply pipe, to the outlet of the inner supply pipe. The outer supply pipe has a narrowed diameter section downstream of the insertion position of the inner supply pipe, and smoothly transitions from upstream to downstream to the narrowed diameter section. Fluid outside the inner supply pipe (a first fluid) flows through the radial gap between the inner and outer supply pipes in the overlapping extension region and is decelerated and pressurized at the narrowed diameter section, converting the dynamic pressure head into a static pressure head.

[0054] The outlet of the internal supply pipe can be like Figure 1 The location shown is upstream of the narrowing section of the external supply pipe, and can also be found in the second embodiment of the jet mixer of the present invention, as shown. Figure 2 It is arranged at the narrowing section of the external supply pipe, as shown.

[0055] In the first and second embodiments of the present invention described above, a section of the inner supply pipe extending upstream from the outlet of the inner supply pipe has a plurality of radially concave portions, wherein the radially inner edge of each radially concave portion extends to the outlet of the inner supply pipe and gradually tapers in the direction toward the outlet of the inner supply pipe, but does not contact each other at the outlet of the inner supply pipe, that is, in Figure 3 The radially concave section shown in the cross-sectional view forms a "petal" shape.

[0056] Here, it is only specified that the radial concave portion is arranged in a section of pipe upstream from the outlet of the inner supply pipe. This section of pipe can extend all the way to the position where the inner supply pipe is inserted into the outer supply pipe. However, considering the disturbance to the flow, the preferred technical solution is still to leave a section of pipe upstream of this section without the radial concave portion for the inner supply pipe.

[0057] Figure 4 The inner supply pipe of the jet mixer in the first and second embodiments of the present invention is schematically shown separately. Six radially recessed portions, exemplarily shown in the figure, extend within a pipe section upstream of the outlet of the inner supply pipe. The radially recessed portions themselves form grooves of gradually varying depths relative to the fluid outside the inner supply pipe, and the regions between the radially recessed portions relative to the fluid inside the inner supply pipe. These grooves form a "petal" shape in cross-section. Because the Reynolds number decreases exponentially when the fluid flows within the grooves, the two streams of fluid inside and outside the inner supply pipe can avoid turbulence and energy consumption before mixing.

[0058] Figure 5 and Figure 6 A perspective view of the inner flow supply tube of the jet mixer according to the third and fourth embodiments of the present invention is shown schematically, wherein there are different numbers of radial recesses. Figure 5 There are 3 radially concave portions, and Figure 6 The middle section has eight radially recessed sections. When there is no significant need to increase pressure, a technical solution with a larger number of radially recessed sections can be adopted.

[0059] Figures 1 to 6 The schematic diagram shows an internal flow supply pipe with a flush outer radial edge and an inner radial edge at its outlet. In other words, the edges of the internal flow supply pipe outlet are approximately in a single plane. Figure 7 In the jet mixer schematically shown according to a fifth embodiment of the invention, the radially outer edge of the inner supply pipe outlet protrudes further downstream in the axial direction than the radially inner edge. This protruding shape further lengthens the edge of the inner supply pipe outlet, thereby increasing the contact boundary between the two fluids inside and outside the inner supply pipe and promoting their mixing. In a sixth embodiment (not shown), the radially inner edge of the inner supply pipe outlet may also protrude further downstream in the axial direction than the radially outer edge.

[0060] Figure 8A This is a perspective view of the jet mixer of the present invention. Figure 8B This is a simulation diagram of the temperature distribution when two fluids at different temperatures flow through the jet mixer of this invention. The jet mixer shown in the diagram is further connected to a desander at the end. Typically, there can be dozens of desanders on a single main pipe. To save computational resources, only 10 larger diameter desanders are simulated. Figure 8C Further shown Figure 8B The simulated temperature data of the jet mixer at the inlet of each desander unit are shown. The fluid (dilution water) inside the inner supply pipe has a temperature of 20℃ and a flow rate of 12230 lpm, while the fluid outside the inner supply pipe (corresponding to the higher concentration slurry) has a temperature of 60℃ and a flow rate of 19523 lpm. After mixing, the simulated temperature data at the inlet of each desander unit is roughly evenly distributed within a very uniform range of 44.42-44.54℃, with a maximum temperature difference of only 0.12℃. This reflects that the two fluids at different temperatures have been uniformly mixed.

[0061] As a comparison Figure 9A The diagram illustrates a pipeline structure for mixing two fluids via a T-junction before a desander, according to existing technology. Figure 9B This shows fluids flowing through two different temperatures (e.g., 20°C and 60°C). Figure 9A The simulation diagram of the pipeline structure shown particularly illustrates the temperature distribution data at the inlet of the desander unit. The mixed temperature varies significantly, ranging from 40.59℃ to 53.47℃, reflecting a very poor mixing effect.

[0062] Figure 10A This illustrates an alternative pipeline structure, in the prior art, for mixing two fluids via a T-junction before the desander, and... Figure 9A The difference in the technical solution shown is that the second fluid (diluted white water) is introduced from the pipeline bend. Figure 10B The illustration shows fluids flowing at two different temperatures (20°C and 60°C, for example). Figure 10A The simulation diagram of the temperature distribution of the pipeline structure shown shows that the temperature difference at the inlet of the 10 desander units is nearly 20°C, reflecting a very poor mixing effect.

[0063] Here, the applicant notes that even without adding a radial concave portion to the internal flow supply pipe as described in the above embodiments, the jet pump structure itself can be adapted to certain pressurization and mixing requirements. Therefore, it is possible to consider using a jet mixer in a waste paper pulping system to directly connect the upstream and downstream equipment through several upstream pipelines and one downstream pipeline, so that the fluids from the upstream equipment can be pressurized and mixed in the jet mixer and then supplied to the downstream equipment. Figure 11AA perspective view of a jet mixer is schematically shown. The difference between this jet mixer and the one described above is that... Figure 11A The inner supply pipe of the jet mixer shown does not have a radial concave portion, but is simply a conventional circular cross-section pipe shape. Figure 11B Further illustrated in a 3D diagram Figure 11A The diagram shows the pipeline structure connecting the jet pump to the desander. Figure 11C This shows fluids flowing through two different temperatures (e.g., 20°C and 60°C). Figure 11B The simulation diagram shows the temperature distribution of the pipeline structure. The temperature difference at the inlet of the desander unit is approximately 2℃. The simulation results clearly indicate that the lack of a radially concave inner flow pipe corresponds to a slightly worse mixing effect. However, the temperature difference of only about 2℃, while not as effective as the mixing effect of an inner flow pipe with a radially concave shape, is still acceptable.

[0064] Figure 12 A perspective view of another embodiment of the jet mixer of the present invention is schematically shown. The inner supply pipe still extends in a straight line but is used to supply pulp. The outer supply pipe is used to supply dilution water. Since water has better fluidity than pulp, i.e., lower viscosity and less clogging, the bend in the outer supply pipe is designed as a right-angle turn when the required dilution amount is small, with a flow rate as low as 1 m / s. In this way, the dilution water flows outside the pulp being diluted, while the pulp does not pass through the bend, and the flow direction is straight before and after dilution. In the region before the dilution water contacts the pulp, part flows within the flow channel formed by the radial concave portion, and the other part is ejected from the annular gap region between the narrowed pipe diameter and the radial concave portion. Thus, from the contact between the pulp and water, what contacts the pipe wall is water or pulp with a relatively low concentration, and the lubricating effect of the water reduces the frictional loss of the pipe wall.

[0065] The preferred embodiments of the present invention have been disclosed above; however, the spirit and scope of the invention are not limited to the specific content disclosed. Those skilled in the art can develop more embodiments and specific applications based on the teachings of the present invention, and these embodiments and specific applications also fall within the spirit and scope of the present invention. The specific embodiments of the present invention are illustrative rather than limiting in their application to the claims.

[0066] List of reference numerals

[0067] 100 jet mixer

[0068] 10. External flow supply pipe;

[0069] 20 internal flow pipe

[0070] 11. Pipe diameter narrowing section

[0071] 21 Radial recess

[0072] 22 Internal supply pipe outlet

Claims

1. A fluidic mixer, characterized by, The fluidic mixer comprises: an outer supply tube; an inner supply tube inserted into the outer supply tube and extending downstream in overlap with the outer supply tube to an inner supply tube outlet, the outer supply tube having a tube diameter constriction downstream of the insertion position of the inner supply tube, the outer supply tube smoothly transitioning upstream and downstream to the tube diameter constriction, wherein a radial gap between the inner supply tube and the outer supply tube exists at all times in the region of overlap due to the difference in tube diameter; wherein a section of the inner supply tube upstream from the inner supply tube outlet has a number of radially inward recesses, wherein the radially inner edges of each of the radially inward recesses extend to the inner supply tube outlet and taper in the direction towards the inner supply tube outlet but are still not in contact with each other at the inner supply tube outlet.

2. The fluidic mixer according to claim 1, wherein the inner supply tube outlet is located upstream of the tube diameter constriction.

3. The fluidic mixer according to claim 1, wherein the inner supply tube outlet is located at the tube diameter constriction.

4. The fluidic mixer according to claim 1, wherein the inner supply tube outlet is located downstream of the tube diameter constriction.

5. The fluidic mixer according to any one of claims 1 to 4, wherein the section of the inner supply tube having radially inward recesses has an outer edge envelope tapering in the direction towards the inner supply tube outlet.

6. The fluidic mixer according to any one of claims 1 to 4, wherein the outer edge envelope of the section of the inner supply tube having radially inward recesses has a constant diameter.

7. The fluidic mixer according to any one of claims 1 to 4, wherein the section of the inner supply tube having radially inward recesses has an outer edge envelope tapering in the direction towards the inner supply tube outlet.

8. The fluidic mixer according to any one of claims 1 to 4, wherein the radially inner edges of the inner supply tube outlet protrude more axially downstream than the radially outer edges.

9. The fluidic mixer according to any one of claims 1 to 4, wherein the radially outer edges of the inner supply tube outlet are axially flush with the radially inner edges.

10. The fluidic mixer according to any one of claims 1 to 4, wherein the radially outer edges of the inner supply tube outlet protrude more axially downstream than the radially inner edges.

11. The fluidic mixer according to any one of claims 1 to 4, wherein each of the radially inward recesses has the same starting position upstream of the fluidic mixer outlet.

12. The fluidic mixer according to any one of claims 1 to 4, wherein each of the radially inward recesses has a different starting position upstream of the fluidic mixer outlet.

13. The fluidic mixer according to any one of claims 1 to 4, wherein each of the radially inward recesses has the same width in the radial direction.

14. The fluidic mixer according to any one of claims 1 to 4, wherein Each said radially inner recess has a width that tapers radially from inside to outside.

15. The fluidic mixer of any one of claims 1 to 4 wherein, Each said radially inner recess has a width that tapers radially from inside to outside.

16. The fluidic mixer of any one of claims 1 to 4 wherein, The outer supply conduit of the fluidic mixer has a bend and the inner supply conduit is straight, wherein, downstream of the location where the inner supply conduit projects into the outer supply conduit, the outer supply conduit transitions through the bend in the outer supply conduit to extend downstream overlapping the inner supply conduit.

17. The fluidic mixer of any one of claims 1 to 4 wherein, The outer supply conduit of the fluidic mixer is straight and the inner supply conduit has a bend, wherein, downstream of the location where the inner supply conduit projects into the outer supply conduit, the inner supply conduit transitions through the bend in the inner supply conduit to extend downstream overlapping the outer supply conduit.

18. The fluidic mixer of claim 16, wherein, The bend in the outer supply conduit has a right angle turn.

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