HK1259794A1

HK1259794A1 - Heat dissipation apparatus and methods for uv-led photoreactors

Info

Publication number: HK1259794A1
Application number: HK19119569.2A
Authority: HK
Inventors: Fariborz Taghipour
Original assignee: The University Of British Columbia
Priority date: 2016-01-19
Filing date: 2017-01-19
Publication date: 2019-12-06

Description

Heat dissipation apparatus and method for UV-LED photoreactor

Reference to related applications

This application claims priority from U.S. application No.62/280,630 entitled "HEAT disipation APPARATUS and methods FOR UV-LED photo reactors" filed 2016, 1, 19. FOR the united states, this application claims priority from U.S. application No.62/280,630 entitled "HEAT removal APPARATUS AND method FOR UV-LED photo reactor" filed 2016, 1, 19, year 119, under 35u.s.c. U.S. application No.62/280,630 is hereby incorporated by reference herein for all purposes.

Technical Field

The present invention relates to thermal management for ultraviolet (radiation) emitting diode (UV-LED) reactors used to irradiate fluids. Embodiments provide apparatus and methods for providing heat dissipation for UV-LEDs and/or other heat-generating electronics used in UV-LED photoreactors.

Background

Ultraviolet (UV) reactors, reactors that manage UV radiation, are used in many photoreactions, photocatalytic reactions, and photoinitiated reactions. One application of UV reactors is for water and air purification. In particular, UV reactors have emerged in recent years as one of the most promising water treatment technologies. Prior art UV reactor systems typically use low and medium pressure mercury lamps to generate the UV radiation.

Light emitting (radiation) diodes (LEDs) typically emit radiation in such a narrow bandwidth that the radiation emitted by the LED (for many applications) can be considered monochromatic (i.e., having a single wavelength). With recent advances in LED technology, LEDs can be designed to generate UV radiation at different wavelengths, including wavelengths used for DNA absorption and wavelengths that can be used for photocatalyst activation. UV-LEDs have many advantages over traditional mercury UV lamps, including but not limited to compact and robust design, lower voltage and power requirements, and the ability to switch at high frequencies. These advantages of UV-LEDs make them an attractive alternative for replacing UV lamps in UV reactor systems. This replacement also makes it possible to develop new UV reactors with new applications.

For applications such as water disinfection, UV-LED reactors can generally be used to irradiate the fluid. However, in a typical UV-LED reactor, there is considerable heating of the UV-LEDs (or other electronic devices) used in the reactor. Excessive heating of UV-LEDs used in UV-LED photoreactors can reduce radiation output, shorten the useful life of the UV-LEDs, and/or alter the peak wavelength of emitted radiation. By means of suitable thermal management (e.g. heat dissipation) the radiation output of the UV-LED and/or its lifetime performance can be significantly improved. The heat generated by the UV-LED may adversely affect the performance of other electronic components (e.g., mounted on the same Printed Circuit Board (PCB)) that are electronically connected to the UV-LED and/or vice versa.

The foregoing examples of related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.

Disclosure of Invention

The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools, and methods, which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements.

Aspects of the present invention provide apparatus and methods for managing heat generated by UV-LEDs that involve dissipation of the heat generated by the UV-LEDs. Thermal management may enhance the UV-LED radiation output and/or improve the operating life of the UV-LED. Embodiments provide apparatus and methods for providing heat dissipation for UV-LEDs and/or other electronic devices used in UV-LED photoreactors for illuminating fluid streams. As a non-limiting example, the UV-LED reactor may be a fluid treatment reactor, such as a water treatment reactor.

According to some aspects of the invention, fluid flowing through the fluid flow passage of the UV-LED photoreactor is used to dissipate heat generated by the UV-LEDs and/or other electronics of the photoreactor. The UV reactor is configured to circulate a portion of the irradiated fluid near the UV-LED or UV-LED circuit board, and/or to incorporate a thermally conductive material in the wall of the fluid conduit. Heat dissipation may be achieved by a highly thermally conductive material thermally coupled to an LED Printed Circuit Board (PCB) on which one or more UV-LEDs are operatively connected to at least one fluid conduit defining wall of the photoreactor. Such fluid conduit defining walls of the photo reactor may also be made of a highly thermally conductive material. With this thermal coupling, the heat generated by the UV-LEDs is spread through the highly thermally conductive PCB and the at least one highly thermally conductive tube defining wall of the photo-reactor, such that when the fluid flows in the tube of the photo-reactor, it dissipates the heat generated by the UV-LEDs away from the UV-LEDs via the tube defining wall of the photo-reactor. In this configuration, the PCB to which the UV-LEDs are connected may be connected to the fluid conduit directly or via other thermally conductive components of the reactor or via other thermally conductive materials from the side of the PCB to which the UV-LEDs are connected. In some embodiments, thermal coupling may be achieved through regions (e.g., edges) of the metal core PCB that do not have the usual solder mask coating (or have had the solder mask coating removed) and thus have high thermal conductivity. This configuration may improve thermal management and thus radiant power output and lifetime of the UV-LEDs and corresponding UV-LED photoreactors.

One aspect of the invention provides a Ultraviolet (UV) reactor for irradiating a fluid stream with UV radiation. The reactor comprises: a fluid conduit defined by a thermally conductive conduit body for permitting fluid flow therethrough, the thermally conductive conduit body including one or more thermally conductive walls; and a UV light emitting diode (UV-LED) operatively connected to the Printed Circuit Board (PCB), the UV-LED oriented to introduce radiation into the fluid conduit. The PCB includes a thermally conductive substrate having a first surface. The thermally conductive conduit body is in thermal contact with a first surface of a thermally conductive substrate of the PCB. Heat is dissipated from the UV-LEDs via the thermally conductive substrate, the thermal contact between the first surface of the thermally conductive substrate and the thermally conductive pipe body, and from the one or more thermally conductive walls of the thermally conductive pipe body to the fluid flowing through the fluid conduit.

The UV-LED may be oriented to direct radiation having a primary optical axis extending in a first direction from the UV-LED to the fluid conduit. The first surface of the thermally conductive substrate may be planar and have a normal vector oriented substantially along the first direction. In some embodiments, the orientation of the normal vector of the first surface substantially along the first direction means that in any plane the angular difference between the normal vector and the first direction is less than 25 °. In some embodiments, the angular difference is less than 15 °. In some embodiments, the angular difference is less than 5 °.

The thermal contact between the thermal conduction pipe body and the first surface of the thermal conduction substrate of the PCB may include a thermal contact enhancing member sandwiched/interposed between the thermal conduction pipe body and the first surface of the thermal conduction substrate. The thermal contact enhancing member may reduce the thermal contact resistance (increase the thermal contact conductivity) between the thermally conductive pipe body and the thermally conductive base of the PCB. The thermal contact enhancing member may comprise a thermally conductive and deformable thermal pad. The thermal contact enhancing member may comprise a thermally conductive gel or paste. The thermal contact between the thermally conductive conduit body and the first surface of the thermally conductive substrate of the PCB may include a thermally conductive intermediate member sandwiched between the thermally conductive conduit body and the first surface of the thermally conductive substrate.

The PCB may comprise a thermal contact area at which the first surface of the thermally conductive substrate is exposed. Thermal contact between the thermally conductive pipe body and the first surface of the thermally conductive base may be accomplished in this thermal contact area. The solder mask coating of the PCB is removed from the thermal contact areas of the PCB. The PCB may comprise a solder mask covering the first surface of the thermally conductive substrate in a circuit area adjacent to the thermal contact area, in which the UV-LEDs are located.

Fluid flowing through the fluid conduit may contact the one or more thermally conductive walls of the fluid conduit to dissipate heat from the one or more thermally conductive walls of the fluid conduit into the fluid. Contact between the fluid flowing through the fluid conduit and the one or more thermally conductive walls of the fluid conduit may occur at least partially within the UV active region of the reactor.

The heat transfer conduit body may include: a plurality of fluid flow channels, each fluid flow channel defined by one or more thermally conductive walls; and a manifold located at an end of at least two of the plurality of fluid flow channels and shaped to provide fluid communication between the at least two fluid flow channels. The thermal contact between the thermally conductive conduit body and the first surface of the thermally conductive substrate may include thermal contact between the manifold and the first surface of the thermally conductive substrate. The manifold may be integrally formed with the plurality of fluid flow channels. A manifold may be coupled to and in thermal contact with the plurality of fluid flow channels.

The primary optical axis may be substantially parallel to a flow direction of a fluid through the fluid conduit. Where the thermally conductive conduit body comprises a plurality of longitudinally extending fluid flow channels, the primary optical axis may be substantially parallel to the longitudinal direction of fluid flow through the plurality of longitudinally extending fluid channels. A first direction along which the optical axis extends from the UV-LED to the fluid conduit may be opposite to a longitudinal direction of fluid flow in at least one of the plurality of fluid flow channels. The first direction along which the optical axis extends from the UV-LED to the fluid conduit may additionally or alternatively be the same as the longitudinal direction of fluid flow in at least one of the plurality of fluid flow channels.

Another aspect of the invention provides a method for thermal management in a Ultraviolet (UV) reactor for irradiating a fluid stream with UV radiation. The method comprises the following steps: allowing fluid to flow through a fluid conduit defined by a thermally conductive conduit body, the thermally conductive conduit body including one or more thermally conductive walls; operatively connecting a UV light emitting diode (UV-LED) to a Printed Circuit Board (PCB), the PCB including a thermally conductive substrate having a first surface; orienting the UV-LED to introduce radiation into the fluid conduit; and forming thermal contact between the thermally conductive conduit body and the first surface of the thermally conductive base of the PCB; wherein heat is dissipated from the UV-LED via the thermally conductive substrate, the thermal contact between the first surface of the thermally conductive substrate and the thermally conductive tubing body, and from the one or more thermally conductive walls of the thermally conductive tubing body to the fluid flowing through the fluid conduit.

The method may include features similar to the reactor and methods of making, assembling, and/or using the reactor described herein.

In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed description.

Drawings

Exemplary embodiments are illustrated in referenced figures of the drawings. The embodiments and figures disclosed herein are intended to be considered illustrative rather than restrictive.

FIG. 1A is a schematic perspective view of a UV-LED reactor according to an exemplary embodiment of the present invention;

FIG. 1B is a schematic side cross-sectional view of the UV-LED reactor of FIG. 1A;

FIG. 1C is a schematic front view of a UV-LED operatively connected to a PCB of the UV-LED reactor of FIG. 1A;

FIG. 1D is a schematic top cross-sectional view of the UV-LED reactor of FIG. 1A;

FIG. 1E is a schematic exploded perspective view of the UV-LED reactor of FIG. 1A;

FIG. 2 is a perspective view of a portion of a UV-LED reactor according to an exemplary embodiment of the present invention;

FIG. 3A is a schematic perspective view of a UV-LED reactor according to an exemplary embodiment of the present invention;

FIG. 3B is a schematic side view of the UV-LED reactor of FIG. 3A;

FIG. 4 is a schematic top view of a UV-LED reactor according to an exemplary embodiment of the present invention;

FIG. 5 is a schematic top view of a UV-LED reactor according to an exemplary embodiment of the present invention; and

fig. 6 is a schematic top view of a UV-LED reactor according to an exemplary embodiment of the invention.

Detailed Description

Throughout the following description, specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Unless the context indicates otherwise, "fluid" as used herein refers to liquids (including but not limited to water) and/or gases (including but not limited to air).

Unless the context indicates otherwise, "ultraviolet" as used herein refers to electromagnetic radiation having a wavelength shorter than the violet end of the visible spectrum but longer than the X-ray. Generally, ultraviolet refers to electromagnetic radiation having a wavelength of about 10nm to about 400 nm.

The term "thermal contact" is used herein. Unless the context indicates otherwise, thermal contact should be understood to include physical contact between two or more thermally conductive members, such as between metals or between members having thermal conductivity/thermal conductivity comparable/comparable to metals. For example, in some embodiments, a material having a thermal conductivity comparable to that of metal and capable of being "in thermal contact" may comprise a material having a thermal conductivity at room temperature and pressure that is at least 60% of the thermal conductivity of common stainless steel. In some embodiments, such materials have a thermal conductivity greater than 10W/(mK) at room temperature and pressure. In some embodiments, such materials have a thermal conductivity greater than 12W/(mK) at room temperature and pressure. In some cases, thermal contact between components may be enhanced by thermal contact enhancing components. Such thermal contact enhancing members may include pastes, gels, deformable solids, and/or the like that improve thermal conductivity between two or more members in thermal contact.

The present application describes materials and components as being "thermally conductive" or "thermally conductive". Unless the context indicates otherwise, these terms should be understood to refer to materials and components that are thermally equivalent to metals. For example, in some embodiments, materials and/or components having thermal conductivities comparable to those of metals and described as "thermally conductive" or "heat transfer" may include materials having thermal conductivities that are at least 60% of those of common stainless steels at room temperatures and pressures. In some embodiments, such materials have a thermal conductivity greater than 10W/(mK) at room temperature and pressure. In some embodiments, such materials have a thermal conductivity greater than 12W/(mK) at room temperature and pressure.

The present technology relates to reactors (photoreactors) that operate with one or more solid state Ultraviolet (UV) emitters, such as UV light emitting (radiation) diodes (UV-LEDs), UV emitting thin dielectric films, and/or the like, to produce photoreactions in a fluid. One or more photocatalyst structures activated by UV may be used in a photo reactor for photocatalytic reactions. Chemical oxidants may also be added to the reactor to react with the UV radiation and generate highly reactive radicals, such as hydroxyl radicals, for the photoinitiated oxidation reaction. Embodiments of the UV-LED reactor described herein may be efficient and compact, have integrated components, and may provide precise control of its fluidic and optical environments. The UV-LED reactor includes one or more specially designed flow channels and at least one UV-LED configured to illuminate fluid flowing through the flow channels.

Embodiments of the UV-LED reactor may be used for water purification by inactivating microorganisms (e.g., bacteria and viruses) and/or degrading micropollutants, such as chemical contaminants (e.g., toxic organic compounds), using direct photoreaction and/or photocatalytic reaction and/or photoinitiated oxidation. Fluid (e.g., water) flows through the UV-LED reactor by forced convection using, for example, an electric pump. The UV-LEDs may be powered by wall sockets, solar cells or batteries. The UV-LEDs can be automatically turned on and off when water is flowing or stops flowing. A photocatalyst, such as titanium dioxide or other suitable photocatalyst, can be immobilized on a solid substrate (where fluid flows over the substrate) or a porous substrate (where fluid flows over the substrate). In some embodiments, a combination of photocatalyst, catalyst support, and/or co-catalyst may be disposed in a matrix in a fluid flow channel. If applicable, a chemical oxidant may be injected into the reactor. The chemical oxidizing agent may be hydrogen peroxide or ozone or other chemicals. If applicable, a chemical reducing agent may be injected into the reactor.

Reactors operating with one or more UV-LEDs as a UV radiation source have advantages over conventional mercury UV lamps including, but not limited to, their compact and robust design, lower voltage and power requirements, and the ability to turn on and off at high frequencies. Unlike UV lamps, UV-LEDs are radiation sources with individual small dimensions. They can be positioned in the reactor with a higher degree of freedom compared to the arrangement of conventional mercury UV lamps. Furthermore, optimization of reactor geometry as described herein can be utilized to improve the performance of UV-LED reactors. In particular, embodiments of the UV-LED reactor described herein may be optimized to dissipate heat from one or more UV-LEDs (and/or the electronics of the UV-LED reactor), thereby facilitating an increase in the radiation output and lifetime of the UV-LEDs.

To increase or maintain the life of the UV-LEDs, the fluid flowing through and illuminated by the UV-LED reactor may be used to thermally manage the UV-LEDs by transferring heat generated by the UV-LEDs to the illuminated fluid and thereby dissipating heat from the UV-LEDs via the fluid being processed. The UV-LED reactor may be configured such that a portion of the irradiated fluid circulates near the UV-LED or UV-LED circuit board, and/or a thermally conductive material is added to the walls of the fluid conduit of the reactor.

Fig. 1A-1E show a UV-LED reactor 10 according to an exemplary embodiment of the present invention. The UV-LED reactor 10 includes a fluid conduit 20 defined by a thermally conductive conduit body 21, at least one UV-LED 30 operatively connected to a Printed Circuit Board (PCB)40 and oriented to introduce radiation into the fluid conduit 20. More specifically, the UV-LED 30 is oriented to introduce radiation into the fluid conduit 20 by having a primary optical axis 31 extending from the UV-LED 30 in a first direction 33 towards the fluid in the conduit 20. The thermally conductive pipe body 21 includes one or more thermally conductive channel walls 24, which in turn define the fluid flow channels 22 in the reactor 10. An inlet 26 and an outlet 28 are provided for the entry and exit, respectively, of a fluid (e.g., water) into and out of the fluid conduit 20. The primary fluid flow direction is illustrated in fig. 1A and 1D by arrows 35, with arrows 35 illustrating fluid flow entering the reactor 10 from the inlet 26, flowing through the longitudinally extending flow channels 22, turning at the end of the adjacent internal flow channel 22, and exiting from the outlet 28. A UV transparent window 29, such as a quartz or silica glass window, may be embedded in the thermally conductive body 21 between the UV-LED 30 and the flow channel 22. As will be appreciated by those skilled in the art, the UV-LED reactor 10 may include drive circuitry for the UV-LEDs 30 (e.g., the LED driver 32 shown in fig. 2), a microcontroller, a power port, an on/off switch, and/or the like. These common components are not shown in FIGS. 1A-1E to avoid obscuring the drawings. One or more lenses, including collimating lenses, converging lenses, and/or other lenses (not shown) or combinations thereof, may be disposed in the UV-LED reactor 10 between the UV-LEDs 30 and the fluid flow channels 22 to focus the UV-LED radiation pattern into the longitudinally extending fluid flow channels 22 along a primary optical axis 31 corresponding to each UV-LED 30.

The PCB 40 includes a thermally conductive substrate 41 having a first surface 41A. The first surface 41A of the heat conductive substrate 41 is substantially planar and has a normal vector n. As shown in fig. 1B, normal vector n may be oriented substantially along a first direction 33 (i.e., the direction along which radiation is introduced into fluid conduit 20 from UV-LED 30). In some embodiments, the orientation of the normal vector n of the first surface 41A substantially along the first direction 33 means that in any plane the angular difference between the normal vector n and the first direction 33 is less than 25 °. In some embodiments, the angular difference is less than 15 °. In some embodiments, the angular difference is less than 5 °. The heat conductive pipe body 21 is in thermal contact with the first surface 41A of the heat conductive substrate 41 of the PCB 40. In this way, heat is dissipated from the UV-LEDs 30 via the thermally conductive substrate 41, the thermal contact between the first surface 41A of the thermally conductive substrate 41 and the thermally conductive conduit body 21, and from the one or more thermally conductive walls 24 of the thermally conductive conduit body 21 to the fluid flowing through the fluid conduit 20.

Referring to the UV-LED reactor of fig. 1A-1E, the reactor 10 includes an array of longitudinally extending fluid flow channels 22, each such fluid channel 22 being illuminated by a corresponding UV-LED 30, optionally through a corresponding radiation focusing element (not shown) and in the illustrated embodiment through a UV transparent window 29. In other embodiments, each flow channel 22 may be illuminated by more than one corresponding UV-LED and may incorporate multiple radiation focusing elements (one or more radiation focusing elements per UV-LED 30 and/or one or more radiation focusing elements shared between UV-LEDs 30) to focus radiation from the individual UV-LEDs 30. A corresponding UV-LED 30 and/or a corresponding radiation focusing element may be positioned at a longitudinal end of its corresponding longitudinally extending flow channel 22. The reactor 10 may include several UV-LEDs 30 oriented to introduce radiation into one corresponding flow channel 22 (i.e., a many-to-one LED to flow channel ratio). The reactor 10 may comprise several UV-LEDs 30 emitting different UV wavelengths. This can produce a synergistic effect and increase the speed of the photoreaction and photocatalytic reactions. Adjacent pairs of fluid flow channels 22 may be connected at one end, for example by a manifold (such as manifold 160 shown in fig. 2) or some other suitable port, to enable fluid to flow in a tortuous path from one longitudinally extending channel 22 to the other longitudinally extending channel 22. As can be seen from the exemplary embodiment shown in fig. 1A-1E, the fluid travels through a plurality of longitudinally extending channels 22 and makes multiple passes as the fluid travels through the UV-LED reactor 10 between the inlet 26 and the outlet 28.

Referring to the UV-LED reactor 10 in fig. 1A-1E, fluid flows into and out of the UV-LED reactor 10, passes through the longitudinally extending flow channels 22, and is irradiated by UV radiation from the UV-LEDs 30. In the illustrated embodiment, the UV-LEDs 30 are positioned at one end of the fluid conduit 20 and each longitudinally extending fluid flow channel 22. The main optical axis 31 of the radiation from the UV-LED 30 (after being optionally focused by the above-mentioned lens) extends in a first direction 33. These first directions 33 may be substantially parallel to the longitudinal direction of fluid flow in the longitudinally extending channels 22, and may be substantially parallel to the longitudinal extension of the longitudinally extending flow channels 22. Fig. 1A-1E show a diagrammatic flow channel 22 of a fluid conduit 20 being illuminated from one end of the reactor 10. In general, the fluid conduit flow channels of the UV-LED reactor may be illuminated from either or both longitudinal ends of the flow channels. In some embodiments, the UV-LEDs may be located on opposite longitudinal ends of the UV-LED reactor, such that the principal optical axes of radiation from longitudinally opposing UV-LEDs may be in opposite but parallel longitudinal directions.

The fluid flowing over and illuminated by the UV-LEDs 30 may be used to dissipate heat generated by the UV-LEDs 30 and/or other heat generating electronics (not shown) of the reactor 10 from the UV-LEDs 30 (and/or other electronics). In the exemplary embodiment shown in fig. 1A-1E, the reactor 10 is configured such that the irradiated fluid circulates about the UV-LEDs 30 and the PCB 40. The reactor 10 also incorporates a thermally conductive (thermally conductive) tube body 21 that includes thermally conductive channel walls 24 to dissipate heat from the UV-LEDs and the PCB 40. Specifically, the heat conductive pipe body 21 is in thermal contact with the first surface 41A of the heat conductive base 41 of the PCB 40. In this way, heat is dissipated from the UV-LEDs 30 via the thermally conductive substrate 41, the thermal contact between the first surface 41A of the thermally conductive substrate 41 and the thermally conductive conduit body 21, and from the one or more thermally conductive walls 24 of the thermally conductive conduit body 21 to the fluid flowing through the fluid conduit 20. The heat exchange takes place in the UV active region of the UV-LED reactor 10, i.e. in the region of the reactor 10 illuminated by the UV radiation from the UV-LEDs 30.

In some embodiments, the reactor 10 may optionally include a thermal contact enhancement member 50 (shown in fig. 1E) that may be sandwiched in thermal contact between the thermally conductive conduit body 21 and the first surface 41A of the thermally conductive base 41 of the PCB 40. The thermal contact enhancement member 50 comprises a thermally conductive material including, but not limited to, paraffin and/or silicone based materials. In some embodiments, the thermal contact enhancing member 50 may deform (e.g., a deformable pad or deformable gel or paste) to fill small concavities and convexities in the physical contact between the thermally conductive conduit body 21 and the first surface 41A. When sandwiched between the heat conduction pipe body 21 and the first surface 41A, the thermal contact enhancing member 50 can reduce the thermal contact resistance (increase the thermal contact conductivity) between the heat conduction pipe body 21 and the first surface 41A. The thermal contact enhancing member 50 is optional and not required in all embodiments.

The UV-LEDs 30 are operatively connected to the PCB 40 in a circuit area 42. In the circuit area 42, the PCB may be covered (at least in large part) by a solder mask coating 42A in the circuit area 42. To facilitate thermal contact between the thermally conductive conduit body 21 and the first surface 41A of the thermally conductive base 41 of the PCB 40, in some embodiments, an exposed thermal contact area 44 is provided on the first surface 41A. The thermal contact area 44 may be a portion of the first surface 41A that is in thermal contact with the thermally conductive pipe body 21. The solder mask coating 42A may be removed from the first surface 41A of the thermally conductive PCB substrate 41 in the thermal contact area 44. For example, as best shown in fig. 1C, the thermal contact area 44 (e.g., which is free of the solder mask 42) may be located around the edge of the PCB 40, but the thermal contact area 44 may be located in some other suitable area of the PCB 40 that has no electronic components attached and no electrical connections. By way of non-limiting example, the solder mask coating 42 of the PCB 40 may be removed by laser cutting, etching, and/or the like to provide thermal contact between the thermally conductive conduit body 21 and the first surface 41A of the thermally conductive substrate 41 of the PCB 40 to facilitate heat transfer between the LEDs 30, the PCB 40, the channel walls 24, and the fluid flowing in the reactor 10. In some embodiments, the width of the thermal contact area 44 at the edge of the PCB 40 may be several millimeters. Generally, the larger the size of the thermal contact area 44, the higher the heat transfer rate. However, there is a tradeoff because increasing the size of the thermal contact area 44 increases the size of the overall reactor 10. Removing the outer layer (e.g., solder mask 42) to expose thermally conductive substrate layer 41 of PCB 40 results in a significant improvement in the thermal contact/coupling between PCB 40 and thermally conductive channel wall 24 of fluid conduit 20, so that heat from UV-LEDs 30 can be transferred to the fluid traveling through flow channel 22 (e.g., due to the large surface area of channel wall 24 defining fluid flow channel 22, due to the nature of the moving fluid within channel 22, and due to the temperature of the fluid within flow channel 22 which is typically lower than the temperature of PCB 40).

Fig. 2 shows a partial perspective view of a UV-LED reactor 100 according to an exemplary embodiment of the present invention. Many features and components of reactor 100 are similar to those of reactor 10, with the same reference numerals preceded by the numeral "1" being used to indicate features and components of reactor 100 that are similar to those of reactor 10. However, the UV-LED reactor 100 differs from the UV-LED reactor 10 in that the thermally conductive pipe body 121 of the UV-LED reactor 100 includes a thermally conductive manifold 160 that directs fluid flow between the flow channels 122 at one longitudinal end to allow fluid to flow from one longitudinally extending flow channel 122 to another longitudinally extending flow channel 122, as described above in connection with fig. 1A-1E. Although not shown in fig. 2, the reactor 100 may have another manifold 160 at its opposite longitudinal end. The thermally conductive manifold 160 may be integrally formed with the thermally conductive channel wall 124 of the conduit body 121 or may be joined and in thermal contact with the thermally conductive wall 124 of the conduit body 121.

As with the reactor 10 described above, the UV-LED reactor 100 includes a fluid conduit 120 defined by a thermally conductive conduit body 121, at least one UV-LED 130 operatively connected to a Printed Circuit Board (PCB)140 and oriented to introduce radiation into the fluid conduit 120. More specifically, the UV-LEDs 130 are oriented to introduce radiation into the fluid conduit 120 by having a primary optical axis 131 extending from the UV-LEDs 130 in a first direction 133 toward the fluid in the conduit 120. The thermally conductive pipe body 121 includes one or more thermally conductive channel walls 24, which in turn define fluid flow channels 122 in the reactor 110. The PCB 140 includes a thermally conductive substrate 141 having a first surface 141A. The first surface 141A of the heat conductive substrate 141 is substantially planar and has a normal vector n. As shown in fig. 2, normal vector n may be oriented substantially along a first direction 133 (i.e., the direction along which radiation is introduced into fluid conduit 120 from UV-LED 130). In some embodiments, the orientation of the normal vector n of the first surface 141A substantially along the first direction 133 means that in any plane, the angular difference between the normal vector n and the first direction 133 is less than 25 °. In some embodiments, the angular difference is less than 15 °. In some embodiments, the angular difference is less than 5 °. The heat conductive pipe body 121 is in thermal contact with the first surface 141A of the heat conductive base 141 of the PCB 140. In this way, heat is dissipated from the UV-LEDs 130 via the thermally conductive substrate 141, the thermal contact between the first surface 141A of the thermally conductive substrate 141 and the thermally conductive conduit body 121 (via the manifold 160), and from the one or more thermally conductive walls 124 of the thermally conductive conduit body 121 to the fluid flowing through the fluid conduit 120.

Similar to the reactor 10 described above, the reactor 100 may include a thermal contact enhancement member 150 having similar features to the thermal contact enhancement member 150 described above, except that the thermal contact enhancement member 150 is interposed between the manifold 160 and the first surface 141A of the thermally conductive substrate 141 of the PCB 140 (at the thermal contact region 144). The reactor 100 of the embodiment shown in fig. 2 further includes a platen 118 (e.g., made of a rigid material including, but not limited to, stainless steel) that may be coupled to the manifold 160 by suitable fasteners (not shown) to maintain the manifold 160 of the thermally conductive body 121 and the first surface 141 of the PCB 140 in thermal contact with each other, thereby minimizing air gaps and enhancing thermal conductivity.

Similar to the reactor 10 described above, the PCB 140 may include a circuit region 142 on which the LEDs 130 are located, and the circuit region 142 may be covered with a solder mask 142A. Similar to the reactor 10 described above, the solder mask 142A may be removed from the surface 141A of the thermally conductive substrate 141 in the thermal contact region 144, or the thermal contact region 144 may otherwise be free of the solder mask 142A. Fig. 2 shows a UV-LED driver circuit 132, which in the illustrated embodiment is located on the same PCB 140 as the LEDs 130. This is not necessary, and the UV-LED driving circuit 132 may be located elsewhere if space becomes a design limitation.

Although only one longitudinal end of the reactor 100 is shown in fig. 2, the same concept can be applied to the other longitudinal end of the flow channel 122. That is, the fluid in the flow channel 122 may be illuminated by the UV-LEDs from the other longitudinal end and the heat generated by the UV-LEDs (and/or other electronic components of the reactor 100) may be removed in the same manner as described herein for one longitudinal end.

In the exemplary embodiment shown in fig. 1A-1E and 2, the UV-LED reactor comprises a series of longitudinally extending flow channels through which fluid flows in corresponding longitudinal directions, which are illuminated by one UV-LED or an array of UV-LEDs. In a multi-channel reactor such as the embodiments of fig. 1A-1E and fig. 2, fluid flow may pass through the channels in parallel or in series (fluid flow from one channel to another, where the fluid channels are in fluid communication at their ends). In the exemplary embodiment shown in fig. 3A-3B, the UV-LED reactor 200 includes a fluid conduit 220 defined by a thermally conductive conduit body 221 including a single longitudinally extending fluid flow channel 222 for fluid flow therethrough in a corresponding longitudinal direction, which is illuminated by one or more UV-LEDs 230. The primary fluid flow direction is illustrated in fig. 3A-3B by arrows 235, with arrows 235 illustrating fluid entering the UV-LED reactor 200 from the inlet 226, flowing through the longitudinally extending flow channels 222, and exiting from the outlet 228. The UV-LED radiation is focused via a focusing element (not shown here), such as one or more converging and collimating lenses. Fluid flowing in the longitudinal direction in the reactor channel 222 is irradiated by focused radiation from the UV-LED230 in the longitudinal direction of the channel 222. UV-LEDs 230 may be positioned at one or both ends of flow channel 222. The total UV dose (UV fluence) delivered to the fluid can be controlled by adjusting the fluid flow rate and/or adjusting the UV-LED radiation power and/or the number of UV-LEDs on/off. Many features and components of reactor 200 are similar to those of reactor 10, with the same reference numerals preceded by the numeral "2" being used to indicate features and components of reactor 200 that are similar to those of reactor 10.

In the exemplary embodiment shown in fig. 1A-1E and 2, the UV-LED reactor comprises a series of longitudinally extending flow channels through which fluid flows in corresponding longitudinal directions, which are illuminated at one end by one UV-LED or an array of UV-LEDs. In multi-channel reactors such as the embodiments of fig. 1A-1E and 2, the main direction of radiation from the UV-LEDs 30 (optionally after focusing by the lenses discussed above) and the main direction of fluid flow in the longitudinally extending channels 22 are along longitudinal directions that are substantially parallel to the longitudinal extension of the longitudinally extending flow channels 22. In some embodiments, the UV-LEDs may additionally or alternatively be positioned along the flow channel such that radiation from the UV-LEDs is substantially orthogonal to the longitudinal extension of the longitudinally extending flow channel and the primary fluid flow direction of the fluid in the flow channel. For example, fig. 4 shows a top cross-sectional view of a UV-LED reactor 300 according to an exemplary embodiment of the invention. Many features and components of reactor 300 are similar to those of reactor 10, with the same reference numerals preceded by the numeral "3" being used to indicate features and components of reactor 300 that are similar to those of reactor 10.

As can be seen from the exemplary embodiment shown in fig. 4, the fluid travels through a plurality of longitudinally extending channels 322 (defined by the thermally conductive pipe body 321 and its thermally conductive wall 324) and makes multiple passes as the fluid travels through the UV-LED reactor 300 between an inlet and an outlet (not shown here). The fluid flowing through the channels 322 and illuminated by the UV-LEDs 330 may be used to dissipate heat from the UV-LEDs 330 (and/or other electronics) generated by the UV-LEDs 330 and/or other heat generating electronics (not shown) of the reactor 300. In the exemplary embodiment shown in fig. 4, the reactor 300 is configured to circulate the irradiated fluid in the UV active region of the UV-LED 330. More specifically, UV-LED 330 is oriented to direct radiation into fluid conduit 320 by having a primary optical axis extending from UV-LED 330 in a first direction toward the fluid in conduit 320. The thermally conductive pipe body 321 includes one or more thermally conductive channel walls 324, which in turn define fluid flow channels 322 in the reactor 310. The PCB340 includes a thermally conductive substrate having a first surface. The first surface of the thermally conductive substrate is substantially planar and has a normal vector n oriented substantially in a first direction (i.e., in the first direction along which radiation is introduced into the fluid conduit 320 from the UV-LED 330). The meaning substantially along the first direction may have the meaning described elsewhere herein. The thermally conductive conduit body 321 is in thermal contact with a first surface of a thermally conductive base of the PCB 340. In this way, heat is dissipated from the UV-LEDs 330 via the thermally conductive substrate, the thermal contact between the first surface of the thermally conductive substrate and the thermally conductive pipe body 321, and from the one or more thermally conductive walls 324 of the thermally conductive pipe body 321 to the fluid flowing through the fluid pipe 320. The reactor 300 shown in fig. 4 may include other features and components similar to the reactors 10, 110 described above.

For example, fig. 5 shows a top cross-sectional view of a UV-LED reactor 400 according to an exemplary embodiment of the invention. The UV-LED reactor 400 comprises a series of longitudinally stacked reactors 300. The fluid travels through the UV-LED reactor 400 between an inlet and an outlet (not shown here) as described above with respect to fig. 4. The thermal management technique employed by reactor 400 is similar to that described above with respect to fig. 4. Many features and components of reactor 400 are similar to those of reactor 10, with the same reference numerals preceded by the numeral "4" being used to indicate features and components of reactor 400 that are similar to those of reactor 10.

The longitudinally extending fluid flow channels described herein have a cross-section that may take any suitable shape, including but not limited to round, semi-round, square, rectangular, triangular, trapezoidal, hexagonal, and the like. These cross sections can improve reactor performance by improving thermal management. For example, a fluid flow channel having a circular cross-section may provide optimal thermal management to the UV-LEDs (and/or other electronics) of the reactor. In the exemplary embodiment shown in fig. 6, the UV-LED reactor 500 includes a longitudinally extending fluid flow channel 522 having a triangular cross-section. The fluid travels through the UV-LED reactor 500 between an inlet and an outlet (not shown here) as described above with respect to fig. 4. The reactor 500 employs a thermal management technique similar to that described above with respect to fig. 4. Many features and components of reactor 500 are similar to those of reactor 10, with the same reference numerals preceded by the numeral "5" being used to indicate features and components of reactor 500 that are similar to those of reactor 10.

The thermal management techniques described herein utilize a fluid (typically water) to dissipate heat from electronic components (including UV-LEDs) connected on a PCB. This is accomplished by maximizing the thermal contact between the thermally conductive substrate of the PCB and the thermally conductive walls of the fluid conduit that are continuously cooled with fluid moving in the flow channels (and/or manifolds). The resistance to thermal contact of the thermal contact between the thermally conductive conduit body and the thermally conductive substrate of the PCB may be significantly reduced by inserting a deformable and thermally conductive thermal contact enhancing member (e.g., thermal contact member 50, 150) between the thermally conductive conduit body and the first surface of the thermally conductive substrate of the PCB to fill the thermal gap and/or by removing the solder mask coating from the edge (or other area) of the PCB, as described elsewhere herein. Such a thermal contact enhancing member is optional.

Other active or passive heat dissipation and thermal management techniques, such as the use of a heat sink or fluid flow across the back of the PCB (i.e., the side opposite the side to which the UV-LEDs are connected), may also be used in conjunction with the heat dissipation apparatus and methods described herein.

Some embodiments of the UV-LED reactor (not shown here) include a plurality of UV-LEDs illuminating through the longitudinally extending fluid flow channel. In some embodiments (not shown here), multiple radiation focusing elements are incorporated (one for each UV-LED), and the radiation from each UV-LED is focused by its corresponding focusing element. In some embodiments, a group of one or more LEDs may share a set of one or more corresponding focusing elements (or one or more corresponding lenses within one or more corresponding focusing elements) in any suitable manner. For example, there may be a total of 9 LEDs and 3 lenses, where the LEDs are grouped into three groups of 3 LEDs each, and the radiation from each group of 3 LEDs passes through a single lens corresponding to that group of LEDs. UV-LED reactors incorporating a plurality of UV-LEDs may be particularly suitable for fluid flow channels having apertures with relatively large cross-sections. Multiple UV-LEDs may help maximize illumination coverage by increasing illumination in such fluid flow channels compared to embodiments that operate using a single UV-LED to illuminate the fluid flow channels.

The UV-LED reactor of the present invention can be used for a number of photoreactions, photocatalytic reactions and photoinitiated reactions. One particular application is the purification of water or other UV-transparent fluids. Water treatment can be achieved by inactivation of microorganisms (e.g., bacteria and viruses) and degradation of micropollutants, such as chemical pollutants (e.g., toxic organic compounds), by direct photoreaction, photocatalytic reaction, and/or photoinitiated oxidation. Water may flow through the UV-LED reactor through the use of a fluid moving device, such as an electric pump. The UV-LEDs may be powered by wall sockets, solar cells or batteries. If applicable, the photocatalyst may be immobilized on a solid substrate through which the fluid passes, and/or on a porous substrate through which the fluid passes, including, for example, a mesh, a screen, a metal foam, a cloth, or combinations thereof. The photocatalyst supported on a solid and/or perforated substrate may be located in a longitudinally extending fluid flow channel. The photocatalyst may also be located in the cross-section of the fluid flow channel to partially or completely cover the cross-section. If the photocatalyst covers the entire cross-section of the flow channel, a perforated substrate may be used to allow fluid to pass through the photocatalyst substrate. The photocatalyst is irradiated with focused UV radiation from the UV-LED to provide a UV-LED photocatalytic reactor. The photocatalyst may comprise titanium dioxide, or any other photocatalyst. In certain embodiments, a combination of one or more photocatalysts, catalyst supports and promoters are disposed on a solid and/or perforated substrate. If applicable, a chemical agent such as a chemical oxidant may be injected into the UV reactor. The chemical oxidizing agent may include hydrogen peroxide, ozone, or other chemicals. The UV-LEDs can be turned on and off automatically by an external signal. The reactor may include one or more components to inhibit fluid flow in the conduit, such as static mixers, vortex generators, baffles, and/or the like.

In some embodiments, static mixers, vortex generators, baffles, and the like may be deployed in the longitudinally extending fluid flow passage to increase mixing and/or to cause the fluid flow to rotate as it passes through the fluid flow passage. This can improve UV-LED reactor performance by delivering a more uniform UV dose or by improving mass transfer near the photocatalyst surface where the photocatalyst is present in the reactor. Static mixers, vortex generators, baffles, and the like may also be used as flow restriction elements that can be dynamically adjusted to accommodate various incoming flow conditions to match the UV radiation fluence rate profile in the fluid flow channel.

The thermally conductive piping body of the embodiments of the UV-LED reactor described herein may be made of aluminum, stainless steel, or any other sufficiently strong material such as metals, alloys, high strength plastics, and the like. The inner walls of the fluid conduit defining the fluid flow channel may be (but need not be) made of or coated with a material having a high UV reflectivity to reflect any portion of the radiation incident on the inner walls to the fluid.

Although the embodiments described herein are presented with particular features and fluid flow channel configurations or lens configurations, etc., it should be understood that any other suitable combination of features or configurations described herein may be present in a UV-LED reactor.

In addition, the UV-LED reactor may combine UV-LEDs having different peak wavelengths to produce a synergistic effect, thereby improving the photoreaction efficiency.

In some embodiments, the UV-LED reactor comprises a flat flow channel covered with a quartz or silica glass window, which is illuminated by an array of UV-LEDs. This configuration can have two different forms:

a. fluid flowing in channels (including parallel channels) is illuminated by the UV-LEDs mainly in a direction perpendicular to the axis of the flow channel length (or main flow direction). In this case, the LEDs are positioned along the length of the flow channel. The flow moves mainly under/over the UV-LEDs and is illuminated.

b. The fluid flowing in the channel is illuminated by the UV-LEDs mainly in a direction parallel to the axis of the flow channel length (or main flow direction). In this case, the LED is positioned at one or both ends of the flow channel. The flow is mainly moving towards or away from the UV-LED and is illuminated.

In any of these configurations, the exposure of the fluid to UV radiation may be controlled. The flow channels and the UV-LED array may be arranged in such a way that the flow is exposed to a desired number of LEDs. The design may be a single flow channel, a series of parallel flow channels or a stack of multiple flow channels. The total UV dose delivered to the fluid can be controlled by adjusting the flow rate and/or adjusting the UV-LED power and/or turning on/off the number of UV-LEDs. This design enables the fabrication of thin planar UV-LED reactors. For example, in some embodiments, the UV-LED reactor may be approximately the size of a cell phone, in terms of geometry and size, with inlet and outlet ports for fluids.

In some embodiments, the plurality of LEDs are positioned along the length of the longitudinally extending fluid flow channel such that the primary illumination direction is perpendicular to the primary flow direction. The LEDs may be positioned along one or opposite sides of the longitudinally extending fluid flow channel. The flow may move primarily below (or above) the UV-LED and may be illuminated as it travels in a longitudinal direction through the longitudinally extending fluid flow channel. The inner walls of the channels may be made of or coated with a material having a high UV reflectivity to facilitate the transmission of radiation to the fluid. Two adjacent fluid flow channels may be connected at one end to allow fluid to pass from one channel to the other (the fluid undergoing multiple passes through the reactor). Different lenses, including collimating, diverging, converging, and other lenses, may be installed in the UV-LED reactor to adjust the UV-LED radiation pattern.

Specific applications of UV-LED reactors include, for example, processing and treating low to moderate flow rates of water in point-of-use applications. Furthermore, due to its compact configuration and high efficiency, the UV-LED reactor according to embodiments described herein may be incorporated into household appliances (e.g., refrigerators, freezers, water coolers, coffee makers, water dispensers, ice makers, etc.), health care or medical equipment or facilities, dental equipment, and any other equipment requiring the use of clean water. The UV-LED reactor may be incorporated into the apparatus or applied as an add-on to an existing apparatus. For example, the UV-LED reactor may be positioned somewhere through the water conduit such that the UV-LED reactor treats water used in the device (e.g., through the water conduit of the device). This may be particularly beneficial in situations where the fluid must be irradiated/treated as it passes through the pipe, or where it is desired to prevent the formation of a potential microbial biofilm inside the pipe, or where the stream requires treatment at the end of the pipe before it is used. The UV-LED reactor may be integrated in the device along with one or more other forms of water purification methods, such as filtration. Exemplary point-of-use fluid treatment applications of the UV-LED reactor are described next with reference to fig. 7 to 9.

Fig. 7 shows a water treatment system 600 that includes an inlet conduit 626, an outlet conduit 628, and a faucet 605, and incorporates a UV-LED reactor 610 that operates to treat water using UV-LEDs 630. Water enters the reactor 610 via inlet 626, passes through the UV-LED reactor 610 and is irradiated by UV radiation emitted from the UV-LEDs 630, and then exits from the outlet pipe 638 and goes to the faucet 605 for ordinary use. The general fluid flow direction is shown by the arrows. Many features and components of reactor 610 are similar to those of reactor 10, with features and components of reactor 600 that are similar to those of reactor 10 being identified using the same reference numerals preceded by the numeral "6".

In some embodiments, the UV-LED reactor may be incorporated in an appliance that dispenses or uses water (or water-based fluid) for human consumption, such as a freezer, water cooler, coffee machine, vending machine, or the like. Water for human consumption needs to be highly purified. For example, the main water supplies for refrigerators, freezers, and water coolers may contain harmful pathogens. This is particularly a concern in developing countries and remote areas where water may not be properly treated prior to distribution in a water network. Furthermore, due to its particular structure, refrigerator/freezer water pipes can be prone to biofilm and microbial contamination. Polymer pipes typically transfer water from a main water supply to a refrigerator for indoor ice and drinking water. Bacterial biofilms can form in water pipes, particularly when water is not used (e.g., biofilms can form within 8 hours). The intermittent water mode results in the entire water column staying in the water pipe for a long time the day. The sensitivity of water supply pipes to bacterial colonization and biofilm formation on surfaces is a recognized problem.

The UV-LEDs of the reactor can be automatically turned on and off in response to the water starting and stopping flow. A sensor may be used to detect the flow of fluid and send a signal to the reactor to turn the UV-LEDs on or off. The UV-LED reactor can reduce microbial contamination in the water (for consumption) exiting the water pipe and reduce the risk of infection. This is facilitated by the operating state of the UV-LED. For example, UV-LEDs can operate over a range of temperatures and can be turned on and off at high frequencies, which is particularly important for refrigerator and water cooler applications.

Any appliance that dispenses or uses water or water-based fluids for human consumption (e.g., coffee or other beverages) may be combined with the UV-LED reactor according to embodiments described herein to process the water. For example, fig. 8 shows a refrigerator 700 including a body 711 and a conduit 713 for delivering water to a water/ice dispenser 714. The refrigerator 700 incorporates a UV-LED reactor 710. Many features and components of reactor 710 are similar to those of reactor 10, with like reference numerals preceded by the numeral "7" being used to indicate features and components of reactor 710 that are similar to those of reactor 10. The water flowing in conduit 713 passes through UV-LED reactor 710 where it is irradiated with UV radiation before entering water/ice dispenser 714. The general fluid flow direction is shown by the arrows. Similarly, other household appliances that may benefit from incorporating a UV-LED reactor include, but are not limited to, freezers, ice makers, frozen beverage makers, water coolers, coffee makers, vending machines, and the like.

Other applications of UV-LED reactors according to embodiments described herein include the treatment of water or other fluids in healthcare or dental related or medical equipment or facilities for surgery, cleaning or another purpose requiring clean water. In particular, many healthcare applications require higher water quality standards than drinking water. The efficiency and compactness of the UV-LED reactors described herein may make them more attractive than conventional UV lamp reactors for implementation in healthcare facilities.

For example, fig. 9 shows a hemodialysis machine 800 that includes a body 821 and tubing 823 that contains a UV-LED reactor 810. The water flowing in the tubing 823 passes through the UV-LED reactor 810 for treatment before use in the hemodialysis machine. Many features and components of reactor 810 are similar to those of reactor 10, with the same reference numerals preceded by the numeral "8" being used to indicate features and components of reactor 810 that are similar to those of reactor 10. Similarly, other appliances that may benefit from incorporating a UV-LED reactor include, but are not limited to, colonic hydrotherapy devices and dental devices that dispense water for cleaning or surgery, and the like.

With respect to use in dental equipment, investigations of dental equipment water pipes (DUWL) have shown that biofilm formation is a problem and that most of the bacteria that have been identified in DUWL are ubiquitous. Although such bacteria may be present in only small amounts in a domestic water distribution system, they may be active as a biofilm on the luminal surface of a narrow bore water pipe in a dental unit. Microorganisms from contaminated DUWL are spread by aerosol and splashes generated by the working unit handle. Various studies emphasize the need to reduce microbial contamination in DUWL.

In some embodiments, a UV-LED reactor may be incorporated in a dental unit to treat water used in the unit. The UV-LED reactor may be integrated in a dental unit, such as a dental chair, or the UV-LED reactor may be placed in a tray (auxiliary tray) of a dental chair holding a water mist, or in a water spray handle, or elsewhere through a water pipe, to treat the water before use. Features including instant on and off may be included in a UV-LED reactor integrated in the dental unit.

Some embodiments include a UV-LED operating in a pulsed mode. For example, the LEDs may be pulsed at a high frequency. This mode of operation can affect the photoreaction rate as well as the electron-hole recombination of the photocatalyst in order to increase the photocatalytic efficiency.

In some embodiments, the UV-LEDs may be programmed to turn on and off automatically. For example, it may be desirable to turn the UV-LEDs on/off when the fluid flow starts or stops moving in the reactor (which may be used for water purification in point-of-use applications), or at certain time intervals. To control the on/off state of the UV-LED, a sensor may be used to detect fluid movement in the fluid flow channel. Alternatively, the user may physically activate the sensor directly (e.g., by opening and closing a switch) or as an indirect action (e.g., by opening and closing a tap). This feature advantageously saves energy used by the reactor. As another example, it may be desirable to turn the UV-LEDs on/off at specific time intervals to clean the UV reactor chamber when it is not operating for a period of time, to prevent any potential microbial growth, diffusion of microorganisms from untreated upstream fluids, and/or to prevent any biofilm formation. To control the on/off state of the UV-LEDs, a microcontroller may be applied and programmed to turn on the UV-LEDs for a period of time (e.g., a few seconds) at specific time intervals (e.g., once every few hours).

In some embodiments, at least some of the UV-LEDs may be programmed to adjust their power output or automatically turn on or off in response to receiving a signal. For example, a signal may be generated when the flow rate (or other measurable characteristic) of fluid through the UV-LED reactor changes. In embodiments where the fluid is water, the measurable characteristic may be a characteristic indicative of water quality or concentration of contaminants. Examples of water quality indicators include UV transmittance and turbidity. This configuration may facilitate the directing of appropriate radiant energy to the fluid based on particular operating conditions.

In some embodiments, a visual indicator, such as a Liquid Crystal Display (LCD) or a radiant signal (e.g., a colored LED) may be provided on the UV-LED reactor or at another visible location (e.g., on a faucet in the case of an application for water treatment) to inform the user of the status of the reactor and UV-LEDs. For example, when the UV-LED is on, a flag on the LCD may be displayed or a colored LED may be turned on, which indicates to the user the "on" status of the UV-LED.

Further exemplary embodiments of UV-LED based PHOTOREACTORS that may incorporate the HEAT DISSIPATION AND management methods AND APPARATUS described herein are described in U.S. application Ser. No.62/280,630 entitled "Heat DISSIPATION APPARATUS AND method for UV-LED reactor," filed on month 1, 19, 2016, which is incorporated herein by reference.

Interpretation of terms

Throughout the specification and claims, unless the context clearly requires otherwise:

"including," "comprising," and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is, in the meaning of "including, but not limited to";

"connected," "coupled," or any variant thereof, refers to any connection or coupling, either direct or indirect, between two or more elements; the coupling or connection between the elements may be physical, logical, or a combination thereof;

the words "herein," "above," "below," and words of similar import, when used in this specification, shall refer to this specification as a whole and not to any particular portions of this specification;

"or" referring to a list of two or more items encompasses all of the following interpretations of the word: any item in the manifest, all items in the manifest, and any combination of items in the manifest;

the singular forms "a", "an" and "the" also include any appropriate plural reference.

The directional words such as "longitudinal," "transverse," "horizontal," "front," "back," "top," "bottom," "below," "over," "under …," and the like used in this specification and any appended claims (if present) are dependent upon the particular orientation of the apparatus being described and illustrated. The subject matter described herein may assume a variety of alternative orientations. Therefore, these directional terms are not strictly defined and should not be narrowly construed.

Where a component (e.g., a substrate, an assembly, a device, a manifold, etc.) is referred to above, unless otherwise indicated, reference to that component (including a reference to a "means") should be interpreted as including as equivalents of that component any component which performs the function of the described component (i.e., that is functionally equivalent), including components which are not structurally equivalent to the disclosed structure which performs the function in the illustrated exemplary embodiments described herein.

For purposes of illustration, specific examples of systems, methods, and devices have been described herein. These are examples only. The techniques provided herein may be applied to systems other than the exemplary systems described above. Many changes, modifications, additions, omissions, and substitutions may be made in the practice of the invention. The invention includes variations of the described embodiments that are obvious to a person skilled in the art, including variations obtained by: replacing features, elements and/or aspects with equivalent features, elements and/or aspects; mixing and matching of features, elements and/or aspects from different embodiments; combining features, elements and/or aspects from the embodiments described herein with features, elements and/or aspects of other technologies; and/or omitting combined features, elements and/or aspects from the described embodiments.

Claims

1. A Ultraviolet (UV) reactor for irradiating a fluid stream with UV radiation, the reactor comprising:

a fluid conduit defined by a thermally conductive conduit body including one or more thermally conductive walls for permitting fluid flow therethrough;

a UV light emitting diode (UV-LED) operatively connected to a Printed Circuit Board (PCB), the UV-LED oriented to introduce radiation into the fluid conduit;

wherein the PCB comprises a thermally conductive substrate having a first surface;

wherein the thermally conductive conduit body is in thermal contact with a first surface of a thermally conductive base of the PCB; and is

Wherein heat is dissipated from the UV-LED via the thermally conductive substrate, thermal contact between the first surface of the thermally conductive substrate and the thermally conductive conduit body, and from the one or more thermally conductive walls of the thermally conductive conduit body to fluid flowing through the fluid conduit.

2. A reactor according to claim 1 or any other claim herein wherein the UV-LEDs are oriented to direct radiation having a primary optical axis extending in a first direction from the UV-LEDs to the fluid conduit, and wherein the first surface of the thermally conductive substrate is planar and has a normal vector oriented substantially in the first direction.

3. The reactor of any one of claims 1 to 2 or any other claim herein wherein the thermal contact between the thermally conductive conduit body and the first surface of the thermally conductive base of the PCB comprises a thermal contact enhancing member sandwiched between the thermally conductive conduit body and the first surface of the thermally conductive base, the thermal contact enhancing member reducing the resistance to thermal contact (increasing thermal contact conductivity) between the thermally conductive conduit body and the thermally conductive base of the PCB.

4. A reactor according to claim 3 or any other claim herein wherein the thermal contact enhancement member comprises a thermally conductive and deformable thermal pad.

5. A reactor according to claim 3 or any other claim herein wherein the thermal contact enhancement member comprises a thermally conductive gel or paste.

6. A reactor according to any one of claims 1 to 5 or any other claim herein wherein the thermal contact between the thermally conductive pipe body and the first surface of the thermally conductive substrate of the PCB comprises a thermally conductive intermediate member sandwiched between the thermally conductive pipe body and the first surface of the thermally conductive substrate.

7. A reactor according to any one of claims 1 to 6 or any other claim herein wherein the PCB comprises a thermal contact region to which the first surface of the thermally conductive substrate is exposed, and wherein thermal contact between the thermally conductive pipe body and the first surface of the thermally conductive substrate is completed in the thermal contact region.

8. A reactor according to claim 7 or any other claim herein wherein solder mask coating of the PCB is removed from thermal contact areas of the PCB.

9. A reactor as set forth in claim 7 or any other claim herein wherein the PCB comprises a solder mask covering a first surface of the thermally conductive substrate in a circuit area adjacent the thermal contact area in which the UV-LEDs are located.

10. A reactor according to any one of claims 1 to 9 or any other claim herein wherein fluid flowing through the fluid conduit contacts the one or more thermally conductive walls of the fluid conduit to dissipate heat from the one or more thermally conductive walls of the fluid conduit into the fluid.

11. The reactor of claim 10 or any other claim herein wherein contact between fluid flowing through the fluid conduit and the one or more thermally conductive walls of the fluid conduit occurs at least partially within a UV active region of the reactor.

12. The reactor of any one of claims 1 to 11 or any other claim herein wherein:

the heat conductive pipe body includes: a plurality of fluid flow channels, each fluid flow channel defined by one or more thermally conductive walls; and a manifold located at an end of at least two of the plurality of fluid flow channels and shaped to provide fluid communication between the at least two fluid flow channels; and is

The thermal contact between the thermally conductive conduit body and the first surface of the thermally conductive substrate comprises thermal contact between the manifold and the first surface of the thermally conductive substrate.

13. A reactor according to claim 12 or any other claim herein wherein the manifold is integrally formed with the plurality of fluid flow channels.

14. A reactor according to claim 12 or any other claim herein wherein the manifold is joined to and in thermal contact with the plurality of fluid flow channels.

15. The reactor of any one of claims 1 to 11 or any other claim herein wherein:

the thermally conductive conduit body comprises a plurality of fluid flow channels, each fluid flow channel defined by one or more thermally conductive walls; and is

The thermal contact between the thermally conductive conduit body and the first surface of the thermally conductive substrate of the PCB includes a thermally conductive manifold sandwiched between the thermally conductive conduit body and the first surface of the thermally conductive substrate.

16. The reactor of claim 15 or any other claim herein wherein the thermal contact between the thermally conductive conduit body and the first surface of the thermally conductive base of the PCB comprises a thermal contact enhancing member sandwiched between the thermally conductive conduit body and the first surface of the thermally conductive base, the thermal contact enhancing member reducing thermal contact resistance (increasing thermal contact conductivity) between the thermally conductive conduit body and the thermally conductive base of the PCB.

17. A reactor according to claim 16 or any other claim herein wherein the thermal contact enhancement member comprises a thermally conductive and deformable thermal pad.

18. A reactor according to claim 16 or any other claim herein wherein the thermal contact enhancement member comprises a thermally conductive gel or paste.

19. A reactor according to any one of claims 2 to 18 or any other claim herein wherein the primary optical axis is substantially parallel to the direction of flow of fluid through the fluid conduit.

20. A reactor according to any one of claims 2 to 19 or any other claim herein wherein the thermally conductive pipe body comprises a plurality of longitudinally extending fluid flow channels, each longitudinally extending fluid flow channel defined by one or more thermally conductive walls, and wherein the primary optical axis is substantially parallel to a longitudinal direction of fluid flow through the plurality of longitudinally extending fluid channels.

21. A reactor according to claim 20 or any other claim herein wherein a first direction along which the optical axis extends from the UV-LED into the fluid conduit is opposite to a longitudinal direction of fluid flow in at least one of the plurality of fluid flow channels.

22. A reactor according to any one of claims 20 to 21 or any other claim herein wherein a first direction along which the optical axis extends from the UV-LED into the fluid conduit is the same as a longitudinal direction of fluid flow in at least one of the plurality of fluid flow channels.

23. A method of thermal management in a Ultraviolet (UV) reactor for irradiating a fluid stream with UV radiation, the method comprising:

allowing fluid to flow through a fluid conduit defined by a thermally conductive conduit body comprising one or more thermally conductive walls;

operatively connecting a UV light emitting diode (UV-LED) to a Printed Circuit Board (PCB), the PCB including a thermally conductive substrate having a first surface;

orienting the UV-LED to introduce radiation into the fluid conduit; and

thermally contacting the thermally conductive conduit body with a first surface of a thermally conductive substrate of the PCB;

24. A method according to claim 23 or any other claim herein wherein orienting a UV-LED comprises orienting the UV-LED to direct radiation having a primary optical axis extending in a first direction from the UV-LED to the fluid conduit, and wherein the first surface of the thermally conductive substrate is planar and has a normal vector oriented substantially in the first direction.

25. A method according to any one of claims 23 to 24 or any other claim herein wherein bringing the thermally conductive conduit body into thermal contact with the first surface of the thermally conductive base of the PCB comprises inserting a thermal contact enhancing member between the thermally conductive conduit body and the first surface of the thermally conductive base and thereby reducing the resistance to thermal contact between the thermally conductive conduit body and the thermally conductive base of the PCB (increasing thermal contact conductivity).

26. A method according to claim 25 or any other claim herein wherein the thermal contact enhancing member comprises a thermally conductive and deformable thermal pad.

27. A method according to claim 25 or any other claim herein wherein the thermal contact enhancing member comprises a thermally conductive gel or paste.

28. A method according to any one of claims 23 to 27 or any other claim herein wherein bringing the thermally conductive conduit body into thermal contact with the first surface of the thermally conductive substrate of the PCB comprises interposing a thermally conductive intermediate member between the thermally conductive conduit body and the first surface of the thermally conductive substrate.

29. A method according to any one of claims 23 to 28 or any other claim herein wherein the PCB comprises a thermal contact region to which a first surface of the thermally conductive substrate is exposed, and wherein making thermal contact between the thermally conductive conduit body and the first surface of the thermally conductive substrate comprises making the thermal contact in the thermal contact region.

30. A method according to claim 29 or any other claim herein comprising removing solder mask coating of the PCB from a thermal contact area of the PCB.

31. A method according to claim 29 or any other claim herein wherein the PCB comprises a solder mask covering the first surface of the thermally conductive substrate in a circuit area adjacent the thermal contact area, and wherein operatively connecting a UV-LED to a PCB comprises positioning the UV-LED in the circuit area.

32. A method according to any one of claims 23 to 31 or any other claim herein wherein fluid flowing through the fluid conduit contacts the one or more thermally conductive walls of the fluid conduit to dissipate heat from the one or more thermally conductive walls of the fluid conduit into the fluid.

33. A method according to claim 32 or any other claim herein wherein contact between fluid flowing through the fluid conduit and the one or more thermally conductive walls of the fluid conduit occurs at least partially within a UV active region of the reactor.

34. A method according to any one of claims 1 to 11 or any other claim herein comprising shaping the fluid conduit to comprise: a plurality of fluid flow channels, each fluid flow channel defined by one or more thermally conductive walls; and a manifold at an end of at least two of the plurality of fluid flow channels for providing fluid communication between the at least two fluid flow channels; and wherein thermally contacting the thermally conductive conduit body with the first surface of the thermally conductive substrate comprises thermally contacting the manifold with the first surface of the thermally conductive substrate.

35. A method according to claim 34 or any other claim herein comprising integrally forming the manifold with the plurality of fluid flow channels.

36. A method according to claim 34 or any other claim herein comprising coupling the manifold with the plurality of fluid flow channels and making thermal contact between the manifold and the plurality of fluid flow channels.

37. A method according to any one of claims 23 to 33 or any other claim herein comprising shaping the fluid conduit to comprise: a plurality of fluid flow channels, each fluid flow channel defined by one or more thermally conductive walls; and a manifold at an end of at least two of the plurality of fluid flow channels for providing fluid communication between the at least two fluid flow channels; and wherein thermally contacting the thermally conductive conduit body with the first surface of the thermally conductive base comprises interposing a thermally conductive manifold between the thermally conductive conduit body and the first surface of the thermally conductive base.

38. A method according to claim 37 or any other claim herein wherein bringing the thermally conductive conduit body into thermal contact with the first surface of the thermally conductive base of the PCB comprises inserting a thermal contact enhancing member between the thermally conductive conduit body and the first surface of the thermally conductive base and thereby reducing the resistance to thermal contact between the thermally conductive conduit body and the thermally conductive base of the PCB (increasing thermal contact conductivity).

39. A method according to claim 38 or any other claim herein wherein the thermal contact enhancing member comprises a thermally conductive and deformable thermal pad.

40. A method according to claim 38 or any other claim herein wherein the thermal contact enhancing member comprises a thermally conductive gel or paste.

41. A method according to any one of claims 24 to 40 or any other claim herein wherein the primary optical axis is substantially parallel to a direction of flow of fluid through the fluid conduit.

42. A method according to any one of claims 24 to 41 or any other claim herein comprising shaping the thermally conductive pipe body to comprise a plurality of longitudinally extending fluid flow channels, each longitudinally extending fluid flow channel being defined by one or more thermally conductive walls, and wherein the main optical axis is substantially parallel to a longitudinal direction of fluid flow through the plurality of longitudinally extending fluid channels.

43. A method according to claim 42 or any other claim herein wherein a first direction along which the optical axis extends from the UV-LED into the fluid conduit is opposite a longitudinal direction of fluid flow in at least one of the plurality of fluid flow channels.

44. A method according to any one of claims 42 to 43 or any other claim herein wherein a first direction along which the optical axis extends from the UV-LED into the fluid conduit is the same as a longitudinal direction of fluid flow in at least one of the plurality of fluid flow channels.

45. A Ultraviolet (UV) reactor for irradiating a fluid stream with UV radiation, the reactor comprising:

a fluid conduit defined by one or more thermally conductive walls for permitting fluid flow therethrough;

a thermal contact enhancement member in thermal contact with the one or more thermally conductive walls of the fluid conduit;

at least one UV light emitting diode (UV-LED) operably mounted on the thermally conductive printed circuit board, the UV-LED oriented to introduce radiation into the fluid conduit;

wherein the printed circuit board includes a thermal contact area without a solder mask coating therein;

wherein the thermal contact area of the printed circuit board is in thermal contact with the thermal contact enhancing member to provide thermal contact between the thermal contact area of the printed circuit board, the thermal contact enhancing member and the one or more thermally conductive walls of the fluid conduit.

46. A reactor according to claim 45 or any other claim herein wherein the thermal contact between the thermal contact area of the printed circuit board, the thermal contact enhancing member and the one or more thermally conductive walls of the fluid conduit is accomplished directly or through other thermally conductive members.

47. A reactor according to any one of claims 45 to 46 or any other claim herein wherein the fluid conduit comprises: a plurality of fluid flow channels defined by the one or more thermally conductive walls; and a manifold shaped for directing fluid between the plurality of fluid flow channels.

48. A reactor according to claim 47 or any other claim herein wherein the thermal contact enhancement member comprises a thermally conductive and deformable thermal pad disposed between and in thermal contact with the manifold and a thermal contact region of the printed circuit board.

49. A method of thermal management in a Ultraviolet (UV) reactor for irradiating a fluid stream with UV radiation, the method comprising:

allowing fluid to flow through a fluid conduit defined by one or more thermally conductive walls;

providing a thermal contact enhancing member in thermal contact with the one or more thermally conductive walls of the fluid conduit;

operatively mounting at least one UV light emitting diode (UV-LED) on a printed circuit board and orienting the UV-LED to introduce radiation into the fluid conduit;

removing the solder mask coating of the printed circuit board from the thermal contact area of the printed circuit board;

thermally contacting between a thermal contact area of the printed circuit board, the thermal contact enhancing member, and the one or more thermally conductive walls of the fluid conduit.

50. A method according to claim 49 or any other claim herein wherein bringing thermal contact between a thermal contact area of the printed circuit board, the thermal contact enhancing member and the one or more thermally conductive walls of the fluid conduit comprises completing the thermal contact directly or through other members.

51. A method according to claim 50 or any other claim herein comprising shaping the fluid conduit to comprise: a plurality of fluid flow channels defined by the one or more thermally conductive walls; and a manifold shaped for directing fluid between the plurality of fluid flow channels.

52. A method according to claim 51 or any other claim herein wherein the thermal contact enhancing member comprises a thermally conductive and deformable thermal pad disposed between and in thermal contact with a thermal contact region of the printed circuit board and the manifold.

53. A UV reactor comprising any feature, combination of features, or sub-combination of features of any other claim set forth herein and/or any embodiment or aspect described herein or shown in the accompanying drawings.

54. A method comprising any feature, combination of features, or sub-combination of features of any other claim set forth herein and/or any embodiment or aspect described herein or shown in the accompanying drawings.