Anti-winding static mixer for open channel

Abstract

The present invention relates to a static mixer conduit (10) in the form of a channel (11) with a top opening, wherein the static mixer conduit includes an inlet (16) at an upstream end of the channel, an outlet (18) at a relatively downstream end of the channel, and at least two blades (22, 22') arranged at least substantially coplanarly within the channel between the inlet and the outlet, wherein substantially coplanar means that the blades are inclined to each other by no more than 10 degrees relative to a plane extending through the channel, wherein each blade has an upstream surface (32) oriented toward the inlet and an opposite downstream surface (34), wherein at least one additive injection opening (44, 44') is provided in, on, or above the downstream surface of each blade.

Description

Technical Field

[0001] The present invention relates to a static mixer and a static mixer conduit with an improved additive supply system, to a facility comprising the static mixer (conduit), and to a method for adding additives to a fluid and homogenizing the resulting mixture using the static mixer (conduit). Background Technology

[0002] Static mixers and static mixer conduits are used in all industrial applications involving mixing and dispersion, gas-liquid contact, or turbulent mixing. For example, a static mixer typically has a tubular internal structure that produces the desired mixing and dispersion effects as fluid flows around a stationary mixer component. Static mixers offer advantages over other mixing systems, such as dynamic mixers, including smaller size, lower maintenance, simpler installation and cleaning, and superior reliability.

[0003] A significant drawback of known mixers (conduits) is that they cannot efficiently and / or quickly enough homogenize the mixture after a metered feed of another fluid, such as an additive, through the main fluid of the mixer (conduit), and they tend to clog if the fluid being processed contains solids. Efficient homogenization of the mixture after metered feeding of one or more additives (e.g., flocculants, pH controllers, etc.) is particularly challenging when wastewater, which typically contains solids, fibers, sludge, and other components and is prone to clogging static mixers, needs to be mixed with one or more additives (e.g., flocculants, pH controllers, etc.). Conventional static mixers (conduits) clog after relatively short operating cycles during such applications.

[0004] The static mixer disclosed in DE 10 2016 124 042 A1 has blades that are inclined relative to each other with respect to a plane extending through the static mixer. However, these blades are circular, elliptical, or triangular and do not provide better mixing performance. Summary of the Invention

[0005] Therefore, the fundamental objective of this invention is to provide an improved static mixer and static mixer conduit that is used both for mixing turbulent flow and for metering additives into the flow, which rapidly mixes and homogenizes the additives in the fluid, particularly in the case of fluids containing solids (e.g., wastewater containing solids, fibers, sludge, and other components), rapidly homogenizes the additive concentration in the fluid, and provides a uniform distribution of the additives before the fluid / additive mixture reaches the outlet of the static mixer (conduit).

[0006] According to the invention, this objective is achieved by providing a static mixer conduit in the form of a channel with a top opening, wherein the static mixer conduit includes an inlet at an upstream end of the channel, an outlet at a relatively downstream end of the channel, and at least two blades arranged at least substantially coplanarly within the channel between the inlet and the outlet, wherein substantially coplanar means that the blades are inclined to each other by no more than 10 degrees relative to a plane extending through the channel, wherein each blade has an upstream surface oriented toward the inlet and an opposite downstream surface, wherein at least one additive injection opening is provided in, on, or above the downstream surface of each blade.

[0007] This solution is based on the discovery that by arranging at least one additive injection opening on the downstream surface, or above the downstream surface, of each of at least two blades arranged at least substantially coplanarly within the channel between the inlet and outlet, not only is clogging of the static mixer reliably avoided, but rapid mixing and homogenization of the fluid / additive mixture is also achieved, even if the fluid is wastewater containing solids, fibers, sludge, and other components. Particularly advantageously, the additive is added to the static mixer (conduit) according to the invention via one or more additive injection openings disposed on, or above the downstream surface of each blade, i.e., downstream of the static mixer (conduit). For this reason, the static mixer (conduit) according to the invention does not require any additional additive metering device, which in prior art static mixers (conduits) is typically located upstream of the static mixer and acts as a flow obstruction. The blades of the static mixer (conduit) according to the invention generate large counter-rotating vortex pairs, carrying the additive away from the additive injection opening and rapidly and uniformly homogenizing the resulting mixture across the entire channel cross-section. Furthermore, the increased mixing and homogenization efficiency of the static mixer (conduit) according to the invention allows for additive savings and provides high mixing degree in a short mixing time. Furthermore, the pressure loss in the static mixer (conduit) is very low, so the water flow in the gently sloping channel will not stop. In addition, this static mixer is a ready-to-install solution, allowing for fixed installation without the need to change or modify the static mixer according to the water level in the channel. Finally, the simple geometry and low complexity of the static mixer (conduit) according to the invention result in reduced maintenance requirements and lead to simple and cost-effective manufacturing.

[0008] Surprisingly, the blades of the present invention, which are flat plates with a trapezoidal longitudinal cross-sectional shape, particularly in combination with a coplanar arrangement, provide superior mixing and homogenization of fluid / additive mixtures. The trapezoidal shape of the blades helps guide the formation and development of vortices across the entire cross-section of the channel. This geometry ensures that the position of the vortex core is more precisely managed, and the vortex intensity, which is crucial to mixing performance, is enhanced. In contrast to shapes such as circles, ellipses, or triangles, the trapezoidal shape prevents direct currents that could bypass vortices in the middle of the cross-section (especially when the width of the trapezoidal blade increases towards the downstream end). This characteristic significantly enhances the mixing effect. The coplanar arrangement of the blades further improves these effects, ensuring a more efficient and uniform distribution of the additive throughout the fluid. The combination of these features results in a surprising and substantial improvement in mixing and homogenization, exceeding the capabilities of conventional blade designs.

[0009] According to the invention, the term "channel" refers to any hollow space that is closed (e.g., by walls) at its bottom and two longitudinal sides, i.e., sides extending along the longitudinal direction of the channel, while at least a portion of the top is open. In this respect, the longitudinal direction means the direction of any horizontal line extending between the inlet and outlet of the channel. Preferably, the entire top surface of the channel is open, while the front and rear ends of the channel may be closed, open, or at least partially open. For example, the channel may have a channel shape with a square, rectangular, U-shaped, or V-shaped cross-section.

[0010] The upstream and downstream ends of the channel are related to the direction of fluid flow during channel operation, that is, fluid flows from the upstream end to the downstream end of the channel during channel operation.

[0011] Similarly, the upstream and downstream ends of each blade are related to the direction of fluid flow during channel operation, i.e., fluid flows from the upstream end of the blade to the downstream end during channel operation.

[0012] According to the invention, at least two blades are arranged in the channel at least substantially coplanarly, wherein substantially coplanar means that the blades are inclined to each other by no more than 10 degrees relative to a plane extending through the channel, for example, relative to a longitudinal plane or a vertical longitudinal section of the channel.

[0013] According to a preferred embodiment of the invention, the blades are tilted relative to the plane extending through the channel by no more than 5 degrees, more preferably no more than 2.5 degrees, even more preferably no more than 1 degree, and most preferably not tilted.

[0014] According to another preferred embodiment of the invention, the blades are inclined relative to the plane extending through the channel at an angle greater than 0 degrees but not more than 10 degrees, preferably greater than 0 degrees to 10 degrees, and more preferably 1 degree to 5 degrees. For example, the blades are slightly inclined at such a small angle relative to the plane in the same direction, for example, in a vertical longitudinal section, in the direction towards the upstream end of the channel.

[0015] Next, the term "blade" according to the present invention refers to any three-dimensional object. Preferably, each blade is a flat object, that is, an object that is significantly smaller in one dimension than in the other two dimensions. For example, the one dimension is at least 50% smaller than each of the other two dimensions.

[0016] More preferably, at least one of the at least two blades, and more preferably each of the at least two blades, is a plate. According to the invention, a plate refers to any plate having a relatively small height or thickness compared to the other two dimensions. Viewed in the plane containing the two larger dimensions, the plate preferably comprises two opposing, at least substantially parallel surfaces, wherein at least substantially parallel surfaces mean two surfaces inclined at no more than 10 degrees, more preferably no more than 5 degrees, even more preferably no more than 1 degree, and most preferably not inclined.

[0017] This invention does not particularly limit the longitudinal cross-sectional shape of the plate or the shape seen in a top view. For example, the plate may have a circular, elliptical, square, rectangular, trapezoidal, or polygonal longitudinal cross-sectional shape. Therefore, when the plate has a rectangular, square, or trapezoidal longitudinal cross-sectional shape, the height or thickness of the plate is less than the length and width of the plate, respectively; when the plate has a circular longitudinal cross-sectional shape, the height of the plate is less than the diameter of the plate; and when the plate has an elliptical longitudinal cross-sectional shape, the height of the plate is less than the semi-axis and minor axis of the plate. Preferably, the height of the plate is at most 50% of the other two dimensions, more preferably at most 30%, even more preferably at most 20%, still more preferably at most 10%, even more preferably at most 5%, and most preferably at most 1%.

[0018] In a further development of the inventive concept, it is proposed that at least one of the at least two blades, more preferably each of the at least two blades, be a flat plate having a rectangular longitudinal cross-sectional shape. In this embodiment, preferably, the height of the flat plate is at most 10% of the plate length, more preferably at most 5%, and most preferably at most 1%. Furthermore, preferably, the height of the rectangular flat plate is at most 50% of the plate width, more preferably at most 30%, and most preferably at most 20%. Furthermore, preferably, the quotient of the plate length divided by the width is 2:1 to 50:1, more preferably 5:1 to 20:1, and most preferably 7:1 to 14:1, for example, about 10:1.

[0019] Most preferably, at least one of the at least two blades, more preferably each blade, is a flat plate having a trapezoidal longitudinal cross-sectional shape. A trapezoid means a quadrilateral having at least one pair of parallel sides. In this embodiment, viewed in a top view, each blade includes a front edge, a rear edge, and two side edges, wherein each side edge connects one end of the front edge to one edge of the rear edge. While the side edges extend at least substantially along the longitudinal direction of the channel, the front and rear edges extend at least substantially perpendicular to the longitudinal direction of the channel. "At least substantially perpendicular" means that the angle between the corresponding front edge and / or rear edge and the longitudinal direction of the channel is 70 to 110 degrees, preferably 80 to 100 degrees, more preferably 85 to 95 degrees, even more preferably 89 to 91 degrees, and most preferably 90 degrees; and "at least substantially along the longitudinal direction of the channel" means that the angle between the corresponding side edge and the longitudinal direction of the channel is -20 to +20 degrees, preferably -10 to +10 degrees, more preferably -5 to +5 degrees, even more preferably -1 to +1 degree, and most preferably 0 degrees. The leading edge of the blade is closer to the inlet than the opposing trailing edge; that is, the leading edge of the blade is located at the upstream end of the blade, while the trailing edge is located at the downstream end. The leading and trailing edges are parallel to each other, while the side edges may be parallel or non-parallel. Preferably, the side edges are non-parallel. More preferably, the trapezoid is a right-angled trapezoid, i.e., a trapezoid where one side edge has an angle of 90 degrees with the leading and trailing edges, while the other side edge has an angle different from 90 degrees with the leading and trailing edges, for example, 1 to 45 degrees, preferably 1 to 30 degrees, more preferably 2 to 10 degrees. In this embodiment, preferably, the side edge of the blade that forms a 90-degree angle with the leading and trailing edges is the side edge that is located closer to the channel sidewall than the other side edge of the blade.

[0020] Particularly preferred is that the rear edge of the trapezoid is longer than the front edge. Good results are obtained when the quotient of the rear edge length divided by the front edge length is 1.1 to 5, more preferably 1.2 to 3, even more preferably 1.5 to 2.5, and most preferably 1.75 to 2.25, for example, about 2. Furthermore, it is preferable that the quotient of each side edge length divided by the rear edge length is 2 to 25, more preferably 3 to 15, and most preferably 4 to 8.

[0021] In principle, the present invention does not particularly limit the orientation of at least two blades, preferably at least two flat plates. Particularly good results are obtained when at least one of the at least two blades, more preferably each of the at least two blades, is inclined from the upstream end to the downstream end of the channel when viewed in a vertical longitudinal section of the channel. The inclination angle between at least one of the at least two blades, more preferably each of the at least two blades, and the longitudinal direction of the channel is preferably 10 to 80 degrees, more preferably 20 to 70 degrees, and most preferably 30 to 60 degrees. More specifically, the inclination angle is the angle between the upstream or downstream surface of the blade and the longitudinal direction of the channel, respectively; or, if the blade is a flat plate, the inclination angle, viewed two-dimensionally in a vertical longitudinal section, is the angle between the side edge of the blade and the longitudinal direction of the channel.

[0022] Good results are particularly obtained when each blade, preferably a flat plate, is tilted downwards in a vertical longitudinal section of the channel from the upstream end to the downstream end; that is, when the leading edge of each blade, preferably a flat plate, is oriented at the upper part of the channel and the trailing edge is oriented at the lower part of the channel. In this embodiment, the upstream surface of the blade is the lower side of the blade, and the downstream surface of the blade is the upper side of the blade.

[0023] In particular, in this embodiment, the tilt angle between each of the at least two blades and the longitudinal direction of the channel is preferably as described above, i.e., 10 degrees to 80 degrees, more preferably 20 degrees to 70 degrees, and most preferably 30 degrees to 60 degrees.

[0024] In a further development of the inventive concept, it is proposed that each blade extends to at least 80%, more preferably at least 90%, even more preferably at least 95%, and most preferably 100% of the channel height when viewed in the vertical longitudinal section of the channel.

[0025] In a particularly preferred embodiment of the invention, the static mixer conduit includes exactly two blades arranged substantially coplanarly within the channel, i.e., there are no other blades besides these two blades.

[0026] Preferably, the blades of the static mixer conduit are arranged adjacent to each other but spaced apart, so that a gap is formed between adjacent blades.

[0027] The shape of the gap depends on the shape of the blade. When the blade is a flat plate with a rectangular longitudinal cross-section, the gap will be rectangular. However, in the most preferred case where the blade is a flat plate with a trapezoidal longitudinal cross-section where the trailing edge is longer than the leading edge, the gap is preferably trapezoidal.

[0028] Good results are obtained when the gap width between the trailing edges of adjacent blades, i.e. the horizontal distance between the ends of the two trailing edges of the adjacent gap, is 0% to 90%, preferably 0% to 20%, of the width of the static mixer conduit.

[0029] Similarly, preferably, the length of the trailing edge of the blade is 5% to 50% of the width of the static mixer conduit, more preferably 40% to 50%, for example about 45%.

[0030] Furthermore, preferably, the gap width between the leading edges of adjacent blades, i.e., the horizontal distance between the ends of the two leading edges of the adjacent gap, is 20% to 100% of the width of the static mixer conduit, preferably 50% to 80%.

[0031] Alternatively, the length of the leading edge of the blade is preferably 1% to 200% of the width of the gap between the leading edges of adjacent blades, more preferably 10% to 70%, for example about 50%.

[0032] In a further development of the inventive concept, it is proposed that each blade includes at least one side edge and the channel includes two sidewalls and a bottom wall, wherein each blade is connected to a sidewall of the channel via one of its at least one side edge. In this context, connection means that the corresponding side edge of the blade is permanently fixed to the sidewall of the channel. Particularly preferred is that each blade is connected to a sidewall of the channel via one of its at least one side edge such that there is substantially no gap or spacing between the corresponding side edge of the blade and the corresponding sidewall of the channel. Substantially no gap or spacing means that at least 70%, preferably at least 80%, more preferably at least 90%, even more preferably at least 95%, still more preferably at least 99%, and most preferably 100% of the length of the corresponding side edge of the blade is directly connected to the corresponding sidewall of the channel.

[0033] According to another alternative, particularly preferred embodiment of the invention, the blades are not directly connected to the sidewalls of the channel via their side edges, but rather indirectly connected, i.e., each blade includes at least one side edge connected to a frame wall that extends at least substantially perpendicularly and along the longitudinal direction of the channel, wherein the channel includes two sidewalls and a bottom wall, and wherein each blade is connected to the sidewalls of the channel via its frame wall. Again, connection in this context means that the frame wall of the blade is permanently fixed to the sidewall of the channel. Particularly preferred is that each frame wall is connected to the sidewall of the channel such that there is substantially no gap or spacing between the respective frame wall of the blade and the respective sidewall of the channel. Again, substantially no gap or spacing means that the respective frame wall is directly connected to the respective sidewall of the channel for at least 70%, preferably at least 80%, more preferably at least 90%, even more preferably at least 95%, still more preferably at least 99%, and most preferably 100% of the length of the respective frame wall of the blade.

[0034] Depending on the length and / or height of the blades, it may be advantageous for the static mixer duct to also include at least one support beam for each blade. For example, each support beam may be arranged below the blade, extending vertically between the bottom wall of the duct and a corresponding portion of the upstream or lower surface of the blade.

[0035] According to the present invention, at least one additive injection opening is provided on, on, or above the downstream surface of each blade. The present invention does not particularly limit the type and arrangement of the at least one additive injection opening.

[0036] According to a preferred embodiment of the invention, at least one blade, and preferably each blade, includes a cavity and at least two openings in its downstream surface, wherein the cavity is connected to both openings, wherein one of these openings is an additive injection opening, and the other of these openings is connected to an additive source via a pipeline.

[0037] Preferably, the cavity is completely arranged inside the blade.

[0038] The cavity can have any cross-sectional shape, such as circular, rectangular, square, oval, elliptical or polygonal cross-sectional shapes, among which a cavity with a circular cross-sectional shape, that is, a cavity that appears as a cylinder in three dimensions, is preferred.

[0039] In a further development of the inventive concept, it is proposed that, in the foregoing embodiments, at least one downstream surface of a blade, and preferably each downstream surface of all blades, include 1 to 10, more preferably 1 to 5, additive injection openings. Each opening may have any cross-sectional shape, such as circular, rectangular, square, oval, elliptical, or polygonal cross-sectional shapes, wherein openings with circular cross-sectional shapes are preferred.

[0040] Particularly good results are obtained when at least one additive injection opening is located at 50% to 99%, preferably 50% to 80%, and more preferably 60% to 75% of the length of the downstream surface of the blade, viewed from the upstream end to the downstream end. Therefore, in a particularly preferred embodiment, in a vertical longitudinal section of the channel viewed from the upstream end to the downstream end, the blades of the static mixer are inclined downwards, and at least one additive injection opening is arranged on the lower part of the downstream surface of the blade.

[0041] According to another particularly preferred embodiment of the invention, an additive supply device is arranged on the downstream surface of each blade, the device including at least one additive injection opening.

[0042] The present invention does not particularly limit the shape of the additive supply device. For example, the additive supply device may have a circular, rectangular, square, oval, elliptical or polygonal cross-sectional shape, wherein a circular, rectangular or square cross-sectional shape is particularly preferred.

[0043] Particularly good results are obtained when the additive supply device is a conduit having a circular, rectangular, or square cross-sectional shape and connected to the downstream surface of the blade, wherein the conduit includes at least one additive inlet on one of its two front sides and at least one additive injection opening on its opposite front side. Preferably, at least one additive inlet is arranged at the upstream end and in fluid communication with the additive source, while at least one additive injection opening is arranged at the downstream end of the conduit.

[0044] In a further development of the inventive concept, an additive supply device in the shape of a pipe is proposed on the downstream surface of the blade, extending from a first position located at 1% to 30%, preferably 2% to 20%, more preferably 2% to 10% of the blade length, viewed from the upstream end to the downstream end of the blade, to a second position located at 50% to 99%, preferably 50% to 80%, more preferably 60% to 75% of the blade length. Preferably, the end of the pipe at the first position includes at least one additive inlet, and the end of the pipe at the second position includes at least one additive injection opening.

[0045] Furthermore, the preferred additive supply device includes 1 to 10, more preferably 1 to 5, additive injection openings. Each opening may have any cross-sectional shape, such as circular, rectangular, square, oval, elliptical, or polygonal cross-sectional shapes, with openings having a circular cross-sectional shape being preferred.

[0046] Good results are particularly obtained when the static mixer conduit does not include any additive supply device other than at least one additive injection opening connected to the downstream surface of the blades. Therefore, the static mixer conduit preferably does not include any additive supply device or additive injection opening located outside and not connected to any of the at least two blades. In particular, the static mixer conduit preferably does not include additive supply pipes arranged upstream or downstream of the at least two blades.

[0047] The two particularly preferred embodiments described above can be combined with each other. For example, one of the blades may include a cavity connected to one or more additive injection openings, while the other blade includes an additive supply device disposed on its downstream surface, the device including at least one additive injection opening. Alternatively, each blade may include a cavity connected to one or more additive injection openings and an additive supply device disposed on its downstream surface, the device including at least one additive injection opening. However, it is preferable that each blade includes a cavity connected to one or more additive injection openings or includes an additive supply device disposed on its downstream surface, the device including at least one additive injection opening.

[0048] According to another aspect, the present invention relates to a static mixer comprising an inlet at an upstream end, an outlet at an opposite downstream end, and at least two blades arranged at least substantially coplanarly, wherein substantially coplanar means that the blades are inclined at no more than 10 degrees to each other with respect to a plane extending through the static mixer, for example, through a length axis of the static mixer, wherein each blade has an upstream surface oriented toward the inlet and an opposite downstream surface, wherein at least one additive injection opening is provided in, on, or above the downstream surface of each blade.

[0049] The preferred features mentioned above regarding the static mixer conduit are also preferred features regarding the static mixer.

[0050] Therefore, preferably, the blades are inclined relative to the plane extending through the static mixer at an angle not exceeding 30 degrees, more preferably not exceeding 10 degrees, even more preferably not exceeding 5 degrees, even more preferably not exceeding 2.5 degrees, and still more preferably not exceeding 1 degree, and most preferably not inclined. Alternatively, the blades may be inclined relative to the plane extending through the static mixer at an angle greater than 0 degrees but not exceeding 10 degrees, preferably greater than 0 to 10 degrees, and more preferably 1 to 5 degrees. For example, the blades may be slightly inclined at such a small angle relative to the plane in the same direction, for example, in a vertical longitudinal section, towards the upstream end of the static mixer.

[0051] More preferably, at least one of the at least two blades, and more preferably each of the at least two blades, is a flat plate, which may have a longitudinal cross-sectional shape of a circle, ellipse, square, rectangle, trapezoid, or polygon. Preferably, the height of the flat plate is at most 50% of the other two dimensions, more preferably at most 30%, even more preferably at most 20%, still more preferably at most 10%, even more preferably at most 5%, and most preferably at most 1%.

[0052] In a further development of the inventive concept, it is proposed that at least one of the at least two blades, and more preferably each of the at least two blades, be a flat plate having a rectangular longitudinal cross-sectional shape. In this embodiment, the height of the flat plate is preferably at most 10% of the plate length, more preferably at most 5%, and most preferably at most 1%. Furthermore, the height of the rectangular flat plate is preferably at most 50% of the plate width, more preferably at most 30%, and most preferably at most 20%. Additionally, the quotient of the plate length divided by the width is preferably 2 to 50, more preferably 5 to 20, and most preferably 7 to 14, for example, about 10.

[0053] Most preferably, at least one of the at least two blades, and more preferably each blade, is a flat plate having a trapezoidal longitudinal cross-sectional shape. Thus, in a top view, each blade includes a front edge, a rear edge, and two side edges, wherein each side edge connects one end of the front edge to one edge of the rear edge. While the side edges extend at least substantially along the longitudinal direction of the static mixer, the front and rear edges extend at least substantially perpendicular to the longitudinal direction of the static mixer. Preferably, the front and rear edges are parallel to each other, while the side edges may be parallel or non-parallel, preferably non-parallel. More preferably, the trapezoid is a right-angled trapezoid, i.e., a trapezoid where one side edge has an angle of 90 degrees with the front and rear edges, while the other side edge has an angle different from 90 degrees with the front and rear edges, for example, 1 to 45 degrees, preferably 1 to 30 degrees, more preferably 2 to 10 degrees. In this embodiment, preferably, the side edge of the blade that forms a 90-degree angle with the front and rear edges is the side edge that, in the cross-section of the static mixer, is arranged closer to the outer end of the static mixer than the other side edge of the blade.

[0054] Particularly preferred is that the rear edge of the trapezoid is longer than the front edge. Good results are obtained when the quotient of the rear edge length divided by the front edge length is 1.1 to 5, more preferably 1.2 to 3, even more preferably 1.5 to 2.5, and most preferably 1.75 to 2.25, for example, about 2. Furthermore, it is preferable that the quotient of each side edge length divided by the rear edge length is 2 to 25, more preferably 3 to 15, and most preferably 4 to 8.

[0055] Particularly good results are obtained when at least one of the at least two blades, more preferably each of the at least two blades, is tilted in a vertical longitudinal section of the static mixer from the upstream end to the downstream end. The tilt angle between at least one of the at least two blades, more preferably each of the at least two blades, and the longitudinal direction of the static mixer is preferably 10 to 80 degrees, more preferably 20 to 70 degrees, and most preferably 30 to 60 degrees. Most preferably, each blade is tilted downward in a vertical longitudinal section of the static mixer from the upstream end to the downstream end.

[0056] In a particularly preferred embodiment of the invention, the static mixer includes exactly two blades arranged substantially coplanarly within the static mixer, i.e., there are no other blades besides these two blades.

[0057] Preferably, the blades of the static mixer conduit are arranged adjacent to each other but spaced apart, so that a gap is formed between adjacent blades.

[0058] According to a particularly preferred embodiment of the invention, each blade of the static mixer includes at least one side edge connected to a frame wall that is at least substantially perpendicular to and extends along the longitudinal direction of the static mixer.

[0059] In a further development of the inventive concept, at least one blade, and preferably each blade, includes i) a cavity and at least two openings in its downstream surface, wherein the cavity is connected to both openings, one of which is an additive injection opening, and the other of which is connected to an additive reservoir via a pipeline, and / or ii) an additive supply device arranged on the downstream surface of each blade, the device including at least one additive injection opening.

[0060] Preferably, at least one blade's downstream surface and / or additive supply device, and preferably each downstream surface of all blades includes 1 to 10, more preferably 1 to 5, additive injection openings.

[0061] Depending on the length and / or height of the blades, it may be advantageous for the static mixer to also include at least one support beam for each blade. For example, each support beam may be arranged below the blade, extending vertically between the bottom of the static mixer and a corresponding portion of the upstream or lower surface of the blade.

[0062] In another aspect, the present invention relates to a chemical plant, petrochemical plant, oil refinery or water treatment plant, comprising the aforementioned static mixer conduit or the aforementioned static mixer.

[0063] Preferably, the static mixer conduit inlet or mixer inlet is in fluid communication with the liquid flow source, and at least one additive injection opening is in fluid communication with the additive source.

[0064] According to another aspect, the present invention relates to a method for adding an additive to a fluid and homogenizing the resulting mixture, comprising the following steps: i) Feeding fluid into the inlet of the aforementioned static mixer conduit or into the aforementioned static mixer; ii) Allow the additive to pass through at least one additive injection opening; and iii) Remove the homogenized mixture at the outlet of the aforementioned static mixer conduit or at the outlet of the aforementioned static mixer. Attached Figure Description

[0065] The following describes specific embodiments of the present invention with reference to the accompanying drawings.

[0066] Figure 1a This is a partial cross-sectional perspective view of a static mixer conduit according to an embodiment of the present invention.

[0067] Figure 1b yes Figure 1a The image shows a longitudinal sectional view of the static mixer conduit.

[0068] Figure 1c From Figure 1a and Figure 1b The view shown is taken from the upstream end of the blades of the static mixer conduit. Detailed Implementation

[0069] Figure 1a The static mixer conduit 10 shown has the shape of a channel 11, which includes a bottom wall 12, two side walls 14, 14' (only the upper edge of the second side wall 14' is shown), an inlet 16, and an outlet 18. The top 20 of the channel 11 is open. Furthermore, two blades 22, 22' arranged at least substantially coplanarly and two support beams 24, 24' are arranged within the static mixer conduit 10. The two blades 22, 22' are flat plates with a trapezoidal shape in top view, including a front edge 26, a rear edge 28, and two side edges 30, 30', wherein the front edge 26 of the blades 22, 22' is shorter than the rear edge 28. In a vertical longitudinal section from the inlet to the outlet of the channel 11, the blades 22, 22' or the side edges 30, 30' of the blades 22, 22' are inclined downwards, and the angle of inclination α between the upstream surface 32 or the downstream surface 34 of the blades 22, 22' and the longitudinal direction 36 of the channel 11 is approximately 45 degrees. The lower surfaces of blades 22 and 22' are the upstream surfaces 32 of blades 22 and 22', while the upper surfaces are the downstream surfaces 34 of blades 22 and 22'. The two blades 22 and 22' extend to the entire height of channel 11 in a vertical longitudinal section, with the two blades 22 and 22' arranged adjacently but spaced apart from each other, forming a gap 38 between the two blades 22 and 22'. Each of the two blades 22 and 22' is connected to the sidewall 14' of the static mixer conduit 10 by one of its side edges 30'. Each support beam 24 and 24' is arranged below the blades 22 and 22' and extends vertically between the bottom wall 12 of channel 11 and a portion of the upstream surfaces 32 of blades 22 and 22'.

[0070] An additive supply device 40, 40' is arranged on the downstream surface 34 of each of the two blades 22, 22', extending slightly below the trailing edge 32 to approximately 65% ​​of the length of the downstream surface 34 of each of the blades 22, 22'. Each additive supply device 40, 40' has the shape of a square conduit and includes two additive inlets 42, 42' at its upstream end and two additive injection openings 44, 44' at its opposite end. The additive inlets 42, 42' are in fluid communication with an additive source (not shown).

[0071] During operation of the static mixer conduit 10, fluid, such as wastewater, is fed into the inlet 16 of the static mixer conduit 10 and flows from the inlet 16 to the outlet 18 of the static mixer conduit 10. Additives are injected into the fluid downstream of the blades 22, 22' via additive supply devices 40, 40' and additive injection openings 44, 44'. The turbulent flow pattern generated by the geometry of the blades 22, 22' results in efficient mixing of the fluid and additives and leads to excellent homogenization of the fluid-additive mixture.

[0072] Reference number list

Claims

1. A static mixer conduit in the form of a channel with a top opening, wherein the static mixer conduit includes an inlet at an upstream end of the channel, an outlet at a relatively downstream end of the channel, and at least two blades arranged at least substantially coplanarly within the channel between the inlet and the outlet, wherein substantially coplanar means that the blades are inclined at no more than 10 degrees to each other with respect to a plane extending through the channel, wherein each blade has an upstream surface oriented toward the inlet and an opposite downstream surface, wherein at least one additive injection opening is disposed in, on, or above the downstream surface of each blade, wherein each blade is a flat plate having a trapezoidal longitudinal cross-sectional shape.

2. The static mixer conduit according to claim 1, characterized in that, Each of the blades is a flat plate.

3. The static mixer conduit according to claim 1 or 2, characterized in that, The trapezoidal longitudinal cross-sectional shape, viewed in a top view, includes a front edge, a rear edge, and two side edges, wherein each side edge connects one end of the front edge to one edge of the rear edge, wherein the side edges extend at least substantially along the longitudinal direction of the channel, and the front edge and the rear edge extend at least substantially perpendicular to the longitudinal direction of the channel, wherein the front edge is shorter than the rear edge, wherein preferably the quotient of the rear edge length divided by the front edge length is 1.1 to 5, more preferably 1.2 to 3, even more preferably 1.5 to 2.5, and most preferably 1.75 to 2.

25.

4. The static mixer conduit according to any of the preceding claims, characterized in that, Each blade is inclined in a vertical longitudinal section from the upstream end to the downstream end of the channel, wherein the inclination angle between each blade and the longitudinal direction of the channel is preferably 10 to 80 degrees, more preferably 20 to 70 degrees, and most preferably 30 to 60 degrees, wherein preferably each blade is inclined downward in a vertical longitudinal section from the upstream end to the downstream end of the channel.

5. The static mixer conduit according to any of the preceding claims, characterized in that, The static mixer conduit includes exactly two blades arranged at least substantially coplanarly within the channel, and no other blades.

6. The static mixer conduit according to any of the preceding claims, characterized in that, The blades are arranged adjacent to each other but spaced apart, so that gaps are formed between adjacent blades.

7. The static mixer conduit according to any of the preceding claims, characterized in that, Each blade includes at least one side edge and the channel includes two side walls and a bottom wall, wherein each blade is connected to a side wall of the channel by means of one of its at least one side edge, or wherein each blade includes at least one side edge connected to a frame wall that is at least substantially perpendicular to and extends along the longitudinal direction of the channel, wherein the channel includes two side walls and a bottom wall, and wherein each blade is connected to a side wall of the channel by means of its frame wall.

8. The static mixer conduit according to any of the preceding claims, characterized in that, At least one blade, and preferably each blade includes a cavity and at least two openings in its downstream surface, wherein the cavity is connected to both openings, one of which is the additive injection opening, and the other of which is connected to an additive reservoir via a pipeline.

9. The static mixer conduit according to claim 8, characterized in that, The at least one additive injection opening is disposed on the downstream surface of the blade, at a position of 50% to 99%, preferably 50% to 80%, and more preferably 60% to 75% of the length of the downstream surface of the blade as viewed from the upstream end to the downstream end.

10. The static mixer conduit according to any of the preceding claims, characterized in that, An additive supply device is disposed on the downstream surface of each of the blades, the additive supply device including at least one additive injection opening.

11. The static mixer conduit according to claim 10, characterized in that, The additive supply device is a conduit connected to the downstream surface of the blade, wherein the conduit has at least one additive inlet on one front side and at least one additive injection opening on the opposite side, wherein preferably the conduit extends from a first position located at 1% to 30%, preferably 2% to 20%, more preferably 2% to 10% of the blade length, viewed from the upstream end to the downstream end of the blade, to a second position located at 50% to 99%, preferably 50% to 80%, more preferably 60% to 75% of the blade length.

12. The static mixer conduit according to any of the preceding claims, characterized in that, The static mixer conduit does not include any other additive supply device other than the at least one additive injection opening connected to the downstream surface of the blade.

13. A static mixer comprising an inlet at an upstream end, an outlet at an opposite downstream end, and at least two blades arranged at least substantially coplanarly, wherein substantially coplanar means that the blades are inclined at no more than 10 degrees to each other with respect to a plane extending through the static mixer, wherein each blade has an upstream surface oriented toward the inlet and an opposite downstream surface, wherein at least one additive injection opening is disposed in, on, or above the downstream surface of each blade, wherein each blade is a flat plate having a trapezoidal longitudinal cross-sectional shape.

14. A chemical plant, petrochemical plant, oil refinery or water treatment plant, comprising a static mixer conduit according to any one of claims 1 to 12 or a static mixer according to claim 13.

15. A method for adding an additive to a fluid and homogenizing the resulting mixture, comprising the following steps: i) Feeding fluid to the inlet of the static mixer conduit according to any one of claims 1 to 12 or the inlet of the static mixer according to claim 13; ii) Allow the additive to pass through at least one additive injection opening; and iii) Remove the homogenized mixture at the outlet of the static mixer conduit according to any one of claims 1 to 12 or at the outlet of the static mixer according to claim 13.

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