WO2017134167A1

WO2017134167A1 - Stirring tool

Info

Publication number: WO2017134167A1
Application number: PCT/EP2017/052257
Authority: WO
Inventors: Peter Brick; Nils KAUFMANN
Original assignee: Osram Opto Semiconductors Gmbh
Priority date: 2016-02-02
Filing date: 2017-02-02
Publication date: 2017-08-10
Also published as: DE102016101797A1

Abstract

The invention relates to a stirring tool for a photobioreactor, comprising an optical waveguide that has a coupling zone for coupling in light; the optical waveguide extends in a longitudinal direction, is designed to conduct light from the coupling zone to an end zone, is designed to emit light laterally along the longitudinal direction, and has at least one curved section.

Description

agitator

DESCRIPTION The invention relates to a stirring apparatus according to patent applica ^¬ demanding. 1

This patent application claims the priority of German Patent Application DE 10 2016 101 797.3, the disclosure of which is hereby incorporated by reference.

Stirring tools are used, for example, in a photobioreactor, in order to enable mixing of the reactor contents and egg ^¬ ne supply of light to the reactor contents in deeper areas of the reactor. Corresponding stirring tools are known from DE 10 2011 002 763 A1 and EP 2 520 642 A1.

The object of the invention is to provide an improved stirring tool for a reactor, in particular for a photobioreactor.

The object of the invention is achieved by the stirring tool according to claim 1. Further embodiments of the stirring tool are indicated in the dependent claims from ^¬.

An advantage of the stirring tool described is that, on the one hand, an improved stirring function is made possible while maintaining or improving the supply of light.

For this purpose a stirring apparatus comprising a light guide provided schla ^¬ gene, wherein the light conductor comprises a coupling region for Einkop- PelN of light, wherein the light conductor extends along a longitudinal direction, wherein the light guide is configured to guide light from the coupling region to an end portion, wherein the light guide is adapted to emit light along the longitudinal direction laterally, wherein the Optical fiber has at least one arcuate portion.

In one embodiment, the arcuate portion has at least the shape of a partial cone section. This ensures good mixing and good light distribution. Under a conic section, a curve is understood that occurs when a section of a straight double circular cone (rotational ^¬ cone) with a plane. A partial cone section comprises part of the conic section. Ellipse, circle, parabola, hyperbola: Depending on the Nei ^¬ supply angle of the cutting plane relative to the half Öff ^¬ opening angle of the cone, the following conic sections arise. Thus represent partial conical sections ^¬ partial ellipses, partial circles, parabolas or part Teilhy- is perbeln.

In one embodiment, the arcuate portion is formed in the form of a spiral. In one embodiment, the arcuate portion we ^¬ nigstens 180 ° especially at least 360 ° surrounded to a center ^¬ axis.

In one embodiment, wherein the arcuate portion surrounds at least 720 ° about a central axis.

In one embodiment, the arcuate portion is in the form of a spiral having an arcuate portion. The bo ^¬ genförmige section may extend over 360 ° or more, in particular over 720 °. This ensures good mixing and light distribution even in higher reactors.

In one embodiment, the light guide has a first and a second portion, which portions merge into one another, wherein the light guide up to a reversing area extends from the coupling region in the first portion away from the coupling region, wherein the light ^¬ conductor starting from the inversion region over the second portion extends back towards the coupling region. This achieves a further improvement of the mixing and the light distribution.

In one embodiment, the light guide is designed as a closed loop. This provides a stable shape of the light guide.

In one embodiment, the stirring tool has a light source which radiates light into the coupling-in region, the light source having a light-emitting semiconductor chip. The semiconductor chip provides an efficient light source that takes up little space.

In one embodiment, a coupling element is provided between the light source and the light guide in order to couple the light into the light guide. As a result, the light coupling is improved.

In one embodiment the light guide is formed of a material having a refractive index, wherein the Biegeab ^¬ section having a bending radius, wherein the light conductor comprises egg ^¬ NEN round cross section with a diameter, wherein the refractive index of 1.4 to 2, said the Ver ^¬ ratio between the bending radius and the diameter between 2 and 100 is.

In one embodiment, at least two light guides are provided. This allows increased flexibility in the shape of the light guides.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments which will be described in connection with the drawings. Show it

1 is a schematic representation of a first embodiment of the stirring tool, 2 is a top view of the light guide,

3 is a bottom view of the light guide,

4 is a side view of the light guide,

5 shows a cross section through a section of the

Light guide,

6 is a schematic representation of a second embodiment of the stirring tool,

7 shows a schematic view from above of the light guide of FIG. 6,

Fig. 8 is a schematic bottom view of the light ^¬ head of Fig. 6, Fig. 9 is a schematic representation of a Biegeabschnit ^¬ tes of the light guide,

10 is a first diagram showing characteristics for different refractive indices depending on a maximum angle of incidence and depending on the ratio of Ra ^¬ dius to the diameter of the stirring tool,

Fig. 11 is a second diagram, the characteristics for maximum

Angle of incidence depends on the ratio of the bending radius to the diameter and depending on the refractive index,

Fig. 12 is a third diagram showing characteristic curves for various ratios of the bending radius to the diameter, depending on the refractive index and from the maxima ^¬ len angle of incidence,

13 is a fourth diagram showing characteristics for refractive indices depending on a beam angle and as a function of the ratio of the bending radius to the diameter,

Fig. 14 is a fifth diagram showing characteristics for maximum

Angle of incidence as a function of the ratio of

Bending radius to the diameter and depending on the refractive index shows, and

Fig. 15 shows a sixth diagram showing characteristic curves for various ratios of the radius to the diameter in Ab ^¬ dependence of the refractive index and depending on the beam angle.

1 shows a schematic view of a reactor 1, wherein a liquid reactor medium 2 is arranged in the reactor 1, wherein a stirring tool 3 is provided, which is for a mixing of the reactor medium 2 and for a Versor ^¬ supply of the reactor medium 2 with electromagnetic Radiation is used. The stirring tool 3 has a light guide 4, which has a coupling-in region 5 for coupling in light. The light guide 4 extends along a longitudinal direction 6, which is shown as a dashed axis. The light guide 4 is formed from a light-conducting material, for example glass or plastic, or has at least one light-conducting material 4. The light guide 4 has a plurality of arcuate portions 7.

In the illustrated embodiment, the light guide 4 is formed as a spiral with a plurality of arcuate sections, wherein the spiral winds around the longitudinal direction 6.

The light guide 4 extends from the coupling region 5, which lies outside of the reactor 1, up to a rich Endbe ^¬ 8 which is angeord ^¬ net above a floor 50 of the reactor. 1 The arcuate portions 7 in the illustrated embodiment are arranged radially symmetrically about a central axis 9, in which the longitudinal direction 6 is shown. The end region 8 of the light guide 4 is aligned perpendicular to the central axis 9 in the illustrated embodiment. The light guide 4 may also have the form of a helix or a double helix.

Depending on the selected embodiment, the light guide 4 may also be in a plane to be arranged with ^¬ tenachse 9 passes through, and have a plurality of lined-up bogenförmi ^¬ ge portions 7, so that the light guide 4 at least an S-shape, in particular a plurality of juxtaposed S-shapes, along the longitudinal direction 6 in the plane.

The arcuate portions 7 of the light guide 4 form two spiral circles, each with 360 °. The spiral circles of the

Optical fiber 4 have a fixed pitch and a fixed diameter.

The light guide 4 may have a circular shape, an ellipse shape or similar rounded shapes in cross section. In addition, the light guide 4 may also have an angular area in cross section. In particular, the cross section of the

Light guide 4 triangular, square or polygonal design. The coupling region 5 is formed in the illustrated embodiment in the form of a planar cross-sectional area 10 at the upper end of the light guide 4. About the coupling region 5, a light source 11 is arranged. The light source is formed, for example in the form of an optoelectronic rule ^¬ semiconductor chip 11, the electromagnetic radiation on a radiation face 12 emits. In the exemplary embodiment illustrated Darge ^¬ a coupling element in the form of a lens 13 is arranged on the emission side of the semiconductor chip 12. 11 The lens 13 serves to focus the light emitted from the semi-conductor chip 11 ^¬ light in the direction of the cross-sectional area 10th In the illustrated embodiment, the lens 13 is spaced from the cross-sectional area 10. Depending on the selected embodiment, the lens 13 can be dispensed with and the semiconductor chip 11 can rest directly on the cross-sectional area 10. In addition, the lens 13 may also be arranged on the end of the light guide 4. In addition, other types and forms of coupling elements may be provided. Depending on the selected embodiment, the coupling-in region 5 of the optical waveguide 4 can also have coupling-in structures for improved coupling of electromagnetic radiation into the optical waveguide 4. For this purpose, for example, reflectors, lenses, TIR lenses or concentrators can be provided. In addition, the semiconductor chip can also be fixedly connected to the light guide. It is an unillustrated drive ^¬ selement 53, in particular an electric motor provided which rotates the stirring tool with the light guide 4 about the center axis 9.

Fig. 2 shows a schematic view from above of the

Light guide 4 with the cross-sectional area 10 and the arcuate sections 7, which are annular. In this embodiment, the light guide 4 is formed spirally. Depending on the selected embodiment, the light guide 4 may have at least one spiral winding or a plurality of spiral turns.

3 shows a schematic view from below of a view of the light guide 4 with the end region 8.

FIG. 4 shows, in a schematic side view, a section of the optical waveguide 4, which according to the embodiment of FIG. 1 is designed as a spiral.

For stirring the reactor medium 2, the light guide 4 is rotated about the central axis 9, for example. Thus, a mixing of the reactor medium 2 a discharged over the surface 14 of the light guide 4 of electromagnetic radiation is distributed evenly in the reactor volume 1 on the one achieved and walls ^¬ ren. However, other axes of rotation can be used which are not in the center axis 9.

Depending on the selected embodiment, the light guide 4 may have scattering particles or scattering elements in the interior or on the surface 14 in order to couple electromagnetic radiation via the surface 14 into the reactor 1. Further- toward the light guide can have 4 conversion material beispielswei ^¬ se phosphor to move one of the light source 11 Be ^¬ riding asked electromagnetic radiation in the wavelength at least partially. The conversion material can be distributed in the volume of the light guide 4 or arranged as a surface coating on the surface 14 of the light guide 4. Furthermore, scattering centers, for example in the form of particles, diffusers or structures, for example in the form of prisms, tapers or a roughened surface 14, can be used to decouple the electromagnetic radiation.

Fig. 5 shows a cross section through a section of egg ^¬ nes bent portion 7 of the light guide 4. In this embodiment, the surface 14 is covered with a layer of conversion material 15. In addition, or instead of the Kon ^¬ version material 15 and scattering elements 51 such as scatter ^¬ particles or diffusion particles may be provided to couple light from the optical fiber 4 into the reactor 1. In addition, the surface 14 and / or the layer 15 may be formed in the form of a roughened or correspondingly structured surface in order to improve an outcoupling of electromagnetic radiation into the reactor 1. Fig. 6 shows a schematic representation of another embodiment of the stirring tool 3 with the light guide 4, wherein in this embodiment, the light guide as the

Light guide 4 is formed in the form of a closed loop. Starting from the coupling region 5, a first spiral-shaped portion 17 extends to a reverse region 18. Starting from the turnaround section 18 extends a second, also a spiral portion 19 back to the Einkoppelbe ^¬ rich 5. The second section 19 merges into the Einkoppelbe ^¬ rich. 5 Each of the sections 17, 19 has at least 1.5 circular arcs. In addition, the spiral-shaped first and second sections 17, 19 are interlaced. FIG. 7 shows a schematic view of the optical waveguide 4 of FIG. 6 from above and FIG. 8 shows a schematic view of the optical waveguide 4 of FIG. 6 from below.

FIG. 9 shows, in a schematic representation, a partial section of an arcuate section 7 of the light guide 4, which adjoins the coupling-in region 5. Electromagnetic radiation 20 which is emitted from the light emitting element 11 to the cross-section ^¬ surface 10 is coupled to a maximum angle of incidence 21 _Θ Μ into the light guide 4, and guided in the light guide 4 via total reflection at an outer surface of the light guide 4 in the light guide. 4 For larger angles of incidence, the electromagnetic radiation is still coupled into the light guide 4, but no longer totally reflected on the outer surface of the light guide 4. The Lichtlei ^¬ ter 4 has a diameter D. In addition, the light guide 4, starting from the coupling region 5, merges into the curved section 7, the curved section 7 having a radius of curvature R.

A deflected at the cross-sectional area 10 light beam 34 has a beam angle 35 to the center axis 9 of the Lichtlei ^¬ ters 4 on. Depending on the selected embodiment, the refractive index of the light guide and the ratio of the bending radius to the diameter is selected so that preferably 50% or more, in particular 60% or 70% of the coupled into the light guide light within the maximum angle of incidence 21 Θ _Μ are.

Depending on the refractive index n of the light guide 4 different maximum angle of incidence 21 _Θ Μ can be specified, in which the irradiated into the light guide 4 electromag ^¬-magnetic radiation 20 is reflected via total reflection at an inner side of the surface 14 of the portion 7 and the light guide 4 in the direction is guided on the end portion 8. With a refractive index n of 1.5 for the optical fiber 4 and ambient air in the coupling-in area and a reactor medium with a refractive index n of 1.335, the maximum angle of incidence 21 is 43.2 °. Above the maximum angle of incidence kels of 43.2 ° occurs after a coupling of the electromagnetic radiation no total reflection on the inside of the surface 14 of the light guide 4. This Situational ^¬ tion is for guiding the electromagnetic radiation in the light guide 4 of disadvantage.

With a refractive index n of 1.58 for the optical waveguide and ambient air in the coupling region and a reactor medium with a refractive index n of 1.335, the maximum angle of incidence 21 is 51.1 ° for the total reflection after the electromagnetic radiation has been coupled into the optical waveguide 4 the inside of the surface 14 of the Lichtlei ^¬ ters 4 occurs. At a refractive index n of 1.6 for the light guide and air as the environment in the coupling reactor and a medium having a refractive index n of 1.335, the maximum angle of incidence contributes ^¬ be 61.9 ° for the nor after the injection of the electromagnetic radiation into the optical fiber 4 total reflection on the inside of the surface 14 of the light guide 4 occurs. With a refractive index n of 1.67 for the optical waveguide and greater and ambient air in the coupling region and a reactor medium with a refractive index n of 1.335, the maximum angle of incidence is 90 ° for the total reflection after the coupling of the electromagnetic radiation into the optical waveguide 4 Inside the surface 14 of the light guide 4 occurs.

In addition, a critical beam angle 22 with respect to a vertical axis 52 to the surface 14 may be indicated for the various refractive indices n. For example, there is no total reflection at the surface 14 at the refractive index n of 1.5 for a critical beam angle 22 of less than 62.9 °, with a refractive index n of 1.58 at a critical beam angle of less than 51.1 °, with a refractive index n of 1.6 at a critical beam angle 22 of 56.6 °, at a refractive index n of 1.67 kriti a ^¬'s beam angle 22 of 53.1 °.

10 shows a first diagram, in which the maximum angle of incidence 21 Θ _Μ on the ordinate and on the abscissa Ratio R / D between the bending radius R and the diameter D of the bent portion 7 of the light guide 4 are indicated. In addition, characteristic curves 23, 24, 25 for different refractive indices are shown in the diagram of FIG. The first curve 23 is for the refractive index n = 1.6, the second characteristic curve 24 for the refractive index n = 2.0 is = ^¬ give 1.8 and the third characteristic curve 25 for the refractive index n. The characteristic curves 23, 24, 25 represent limits for the maximum angle of incidence 21 Θ _Μ . If the maximum input beam angle Θ _Μ above the characteristic curve, the light is no longer guided by the total reflection in the light guide 4 after being coupled into the light guide 4.

FIG. 11 shows a further diagram in which the refractive index n of the optical waveguide is based on the ordinate and the ratio

R / D of the radius R to the diameter D of the bending section 7 of the light guide 4 are plotted on the abscissa. In addition, characteristic curves for different maximum angle of incidence Θ 21 are given to ^¬. A fourth characteristic curve 26 is indicated for a maximum angle of incidence 21 of 30 °. A fifth characteristic 27 is given for a maximum angle of incidence of 45 °. A sixth characteristic 28 is given for a maximum angle of incidence of 60 °. A seventh characteristic 29 is given for a maximum angle of incidence of 90 °. The characteristics indicate that for a good guidance of the light in Lichtlei ^¬ ter 4, in particular for a total reflection of the light in the optical waveguide 4, a refractive index is required, which is above the specified characteristics 26, 27, 28, 29. 12 shows a diagram in which the ordinate the refractive index n and on the abscissa a maximum angle of incidence 21 Θ _{Μ are} plotted. In addition, ^different characteristic curves 30, 31, 32, 33 are indicated in the diagram. The eighth characteristic 30 is given for a ratio of the radius to the diameter of 1000. The ninth characteristic 31 is given for a ratio of the radius to the diameter of 10. The tenth characteristic 32 is given for a ratio of the radius to the diameter for the value 5. The eleventh characteristic 33 is for a ratio of the radius to the diameter with a Value of 3.3 indicated. For a good guidance of the light in the optical waveguide 4, in particular for a total reflection of the light in the optical waveguide 4, a refractive index is required for corresponding maximum irradiation angles Θ _Μ and the predetermined ratio of radius to diameter, which is above the respective characteristic curve 30, 31, 32, 33 lies.

Fig. 13 is a diagram in which the inner beam angle 35 θ _κ on the ordinate and the ratio R / D of the radius R to the diameter D of the bending portion of the optical fiber are plotted on the abscissa. In addition, further first, second, third characteristic curves are shown. The further first characteristic curve 36 is for a refractive index n of 1.6, the white ^¬ tere second characteristic curve 37 for n is less than 1.8 and the further third characteristic curve plotted for n = 38 2.0. For a good guiding of the light in the light guide 4, in particular for a total reflection at the predetermined ratio R / D of the radius R to a diameter D and a predetermined refractive index n of the internal beam angle 35 must _θ κ are below the corresponding characteristic.

Fig. 14 shows a diagram in which the ordinate represents the refractive index n and the abscissa the ratio R / D of the Ra ^¬ dius R are applied to the diameter D. In addition, further, fourth, fifth, sixth, seventh characteristics for different? ^¬ che maximum internal beam angle 35 are plotted _θ κ. The white ^¬ tere first characteristic is _{κ θ} for a maximum internal beam angle of 10 °, the further fifth characteristic for a maximum of 20 °, the further sixth characteristic curve 41 for a maximum of 30 ° and the further seventh characteristic 42 for an internal beam angle θκ of at most 40 ° indicated. For good guidance of the light rays in the light guide 4, in particular for a Totalrefle xion ^¬ in the light guide 4 with an inner beam angles according to another characteristic of the refractive index across the respective further characteristic must occur. If the ratio R / D of bending radius R to the diameter D of the Lichtlei ^¬ ester 4 at a ratio of R / D = 12 and are all

Light rays with a maximum inner beam angle θ _κ between +/- 40 ° via total reflection in the light guide out are, then the refractive index n of the light guide must be at least 1.89 min ^¬.

FIG. 15 shows a diagram in which the ordinate has the refractive index n and on the abscissa the inner maximum

Beam angle 35 θ _{κ are} plotted. Moreover, are another eighth, ninth, tenth and eleventh characteristic 43, 44, 45, 46 is provided ^¬. Further eighth characteristic curve 43 is for a behaves ^¬ nis radius to diameter of 1000, the additional ninth characteristic curve 44 is for a ratio of radius to diameter of 10, further tenth characteristic curve 45 is for a behaves ^¬ nis the radius to diameter 5, and the other eleventh characteristic 46 is entered for a ratio of radius to diameter of 3.3. To meet good reflection, in particular total reflection, the corresponding values for the refractive index n have the innneren beam angle _{κ θ} exceed the characteristics dependent.

The values shown in the diagrams refer to the situation that the coupling region of the optical fiber is in air and that the light guide is in the Reaktorme ^¬ dium, in particular water having a refractive index of 1.33. Other environments have different values for the graphs and characteristics.

The reactor 1 provides e.g. a photobioreactor, the example of phototrophic microorganisms such as microalgae such as spirulina or chlorella mixed with water as the reactor medium. Phototrophic microorganisms are capable of using light energy using

To convert nutrient elements, CO2 and water into biomass. Depending on the embodiment used, the reactor medium may also include other materials in which agitation and light delivery are beneficial.

The following are formulas for describing the relationship between the refractive index n of the light guide, the angle of incidence _Θ ΜΑΧ ma imum ^¬, the bending radius R of the Biegeab- Section of the light guide, the diameter D of the Lichtlei ^¬ ters and the maximum inner beam angle I NEN

Although the invention in detail by the preferred embodiment has been illustrated and described in detail, the invention is not limited ^¬ by the disclosed examples and other variations can be derived therefrom by the skilled artisan without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1 reactor

2 reactor medium

3 stirring tool

4 light guides

5 coupling area

6 longitudinal direction

7 section

8 end area

9 center axis

10 cross-sectional area

11 semiconductor chip

12 radiation side

13 lens

14 surface

15 conversion material

17 first section

18 reversal area

19 second section

20 radiation

21 angle of incidence

22 critical beam angle

23 to 33 first to eleventh characteristics

34 deflected radiation

35 inner beam angle

36 to 46 further first to further eleventh characteristic

50 floor

51 scattering particles

52 vertical axis

53 drive element

Claims

PATENTA S PRUCHE

1. Stirring tool (3) for a photobioreactor, with a

Optical waveguide (4), wherein the optical waveguide (4) has a coupling-in region (5) for coupling in light, the optical waveguide (4) extending along a longitudinal direction (6), wherein the optical waveguide (4) is designed to emit light from the coupling-in region (5) to lead to an end region (8), wherein the light guide is formed to laterally deliver light along the longitudinal direction (6), wherein the light guide (4) has at least one arcuate portion (7).

2. Stirring tool according to claim 1, wherein the arcuate Ab ^{¬ section} (7) has at least the shape of a partial tapered section.

3. Stirring tool according to one of the preceding claims, wherein the arcuate portion is formed in the form of a spiral ^¬ .

4. Stirring tool according to one of the preceding claims, wherein the arcuate portion surrounds at least 180 °, in particular at least 360 ° about a central axis.

5. Stirring tool according to claim 4, wherein the arcuate Ab ^{¬ section} (7) surrounds at least 720 ° about a central axis.

6. Stirring tool according to one of the preceding claims, where ^¬ in the light guide (4) has a first and a second portion (17, 19), wherein the sections (17, 19) merge into one another, wherein the light guide, starting from the coupling region (5 ) extends in the first portion (17) away from the coupling region (5) to a reversal region (18), wherein the optical fiber (4), starting from the reverse region on the second portion (19) extends back towards the coupling region (5) , Agitating tool according to claim 6, wherein the first and the second portion of the light guide as a closed

Loop are formed.

Beater tool as claimed in any preceding claim, wherein the end portion (8) of the light guide (4) in Wesentli ^¬ surfaces transverse to a longitudinal direction (6) of the light guide (4) is arranged.

Beater tool as claimed in any preceding claim, comprising a light source (11), the light in the coupling region (5) is irradiated, wherein the light source (11) having a light emitting ^¬ semiconductor chip.

Stirring tool according to claim 9, wherein between the light source ^¬ (11) and the light guide (4), a coupling element (12) is provided to couple the light into the light guide (4).

Stirring tool according to one of the preceding claims, wherein the light guide (4) is formed of a material having a refractive index (n), wherein the arcuate Ab ^{¬ section} (7) has a bending radius (R), wherein the light guide (4) having a cross section a diameter (D), wherein the refractive index is between 1.4 and 2, wherein the ratio between the bending radius (R) and the diameter (D) is between 2 and 100. 12. Stirring tool according to one of the preceding claims, wherein at least two light guides are provided.

Stirring tool according to one of the preceding claims, wherein a drive element (53) is provided, wherein the drive element (53) is in operative connection with the light guide (4) in order to rotate the light guide (4) about an axis of rotation.