Systems and methods for fluid disinfection with ultraviolet light

A fluid treatment system includes a reactor chamber fluidly coupled with a fluid inlet and a fluid outlet. The reactor chamber is defined by one or more chamber walls. The system includes a UV LED, and a light pipe. The light pipe extends into the reactor chamber through at least one of the chamber walls. The light pipe has a proximal end disposed outside of the reactor chamber. The proximal end is coupled with the UV LED to transmit UV light into the reactor chamber through the light pipe. To that end, the light pipe also has a distal end, opposite the proximal end, that is disposed within an interior volume of the reactor chamber. The light pipe includes a central section disposed between the proximal end and the distal end. The central section is configured to transmit the UV light from UV LED to the distal end.

FIELD OF THE INVENTION

Illustrative embodiments generally relate to fluid treatment by ultraviolet light and, more particularly, the illustrative embodiments relate to a disinfection chamber having a light pipe at least partially therein.

BACKGROUND OF THE INVENTION

Fluids, including liquid water, are commonly used for many domestic and industrial purposes, such as drinking, food preparation, manufacturing, processing of chemicals, and cleansing. It often is necessary to purify a liquid prior to its use. Filters such as ceramic filters are typically used to remove particulate and chemical impurities from liquids. In addition, a liquid can be exposed to UV radiation to neutralize microorganisms and deleterious pathogens that may be present in the liquid, e.g., bacteria, viruses, and protozoa. Exposure to certain wavelengths of light can disrupt the DNA of many cellular microorganisms—virtually destroying them or rendering them substantially harmless. The exposure to UV radiation can also substantially prohibit the growth and/or reproduction of microorganisms in the liquid.

A system that uses UV radiation to irradiate fluids is often known in the art as a “UV reactor.” Undesirably, conventional UV reactors often suffer from various disadvantages. Specifically, UV light is difficult to extract efficiently from UV light sources, such as light-emitting diodes (LEDs). Consequently, conventional UV reactors often only successfully utilize a fraction of the UV output of such light sources for disinfection (i.e., only a small fraction of emitted UV light is successfully introduced into the liquid to be treated). In addition, UV LEDs often generate a significant amount of heat, particularly since they must frequently be operated at higher currents (generating larger output fluxes) to compensate for inefficient light extraction.

SUMMARY OF VARIOUS EMBODIMENTS

In accordance with one embodiment of the invention, a fluid treatment system includes a reactor chamber fluidly coupled with a fluid inlet and a fluid outlet. The reactor chamber is defined by one or more chamber walls. The system includes an ultraviolent (UV) light-emitting diode. The system also includes a light pipe that extends into the reactor chamber through at least one of the chamber walls. The light pipe has a proximal end disposed outside of the reactor chamber. The proximal end is coupled with the UV LED to transmit UV light into the reactor chamber through the light pipe. To that end, the light pipe also has a distal end, opposite the proximal end, disposed within an interior volume of the reactor chamber. The light pipe includes a central section disposed between the proximal end and the distal end. The central section is configured to transmit the UV light from the one or more of the UV LEDs to the distal end.

In some embodiments, the central section of the light pipe is hollow and has a central section wall with an inner surface. The inner surface of the central section wall may have, or may be formed from, a UV reflective material. In some other embodiments, the central section of the light pipe may be solid. The central section may include an inner portion formed from a UV transmissive material, and an outer portion formed from a UV reflective material. In some embodiments, at least a portion of the central section of the light pipe is coated with a UV reflective material. The UV reflective material may be aluminum, and/or a fluoropolymer such as PTFE.

The UV light is transmitted into the reactor chamber through the distal end. To that end, at least a portion of the distal end may be roughened or textured. In some embodiments, the central section of the at least one light pipe may also be roughened or textured. The distal end of the light pipe extends into the reactor chamber through a chamber wall. At least a portion of the chamber wall through which the light pipe extends may be removable from, and/or attachable to, the reactor chamber.

The LED may be coupled to the light pipe by an attachment material. In preferred embodiments, the attachment material is UV transmissive. Among other things, the light pipe may be formed from quartz, fused silica, and/or sapphire. The chamber walls may be formed from material reflective to UV light. In some embodiments, the UV reflective material is aluminum, and/or a fluoropolymer. The UV LED may be configured to emit UV light having a wavelength ranging between approximately 200 nm and approximately 320 nm. More specifically, the UV LED may be configured to emit UV light having a wavelength ranging between approximately 250 nm and approximately 275 nm.

In accordance with another embodiment, a UV reactor has one or more walls that define a disinfection chamber. The disinfection chamber is configured to have fluid flowing therethrough. The UV reactor also has a UV LED configured to transmit UV light into the disinfection chamber through a light pipe. The light pipe has a proximal end, a distal end, and a central section disposed between the proximal end and the distal end. The distal end extends into the disinfection chamber through a wall of the disinfection chamber. The proximal end is outside of the disinfection chamber and is coupled with the UV LED. The central section has a UV-reflective portion configured to reflect UV light.

In some embodiments, the central section of the light pipe is entirely disposed within a chamber wall. A diameter of the distal end of the light pipe may be larger than a diameter of the central section. A seal may be formed between the light pipe and an interior volume of the disinfection chamber. Among other things, the seal may include an O-ring.

In accordance with yet another embodiment, a method disinfects fluid by providing a fluid treatment system. The fluid treatment system has a reactor chamber fluidly coupled to a fluid inlet and a fluid outlet. The reactor chamber is enclosed by one or more chamber walls. The system includes a UV LED. The system also includes a light pipe that extends into the reactor chamber through at least one of the chamber walls. The light pipe has a proximal end disposed outside of the reactor chamber. The UV LED is coupled to the proximal end to transmit UV light into the reactor chamber through the light pipe. The light pipe also has a distal end, opposite the proximal end, that is disposed within an interior volume of the reactor chamber. The light pipe also has a central section disposed between the proximal end and the distal end. The central section is configured to transmit the UV light from the UV LED to the distal end. The method flows fluid through the fluid inlet into the reactor chamber. The method also activates the UV LED.

Illustrative embodiments may electrically couple the UV LED to a power source using one or more conductive contacts. In some embodiments the one or more of the conductive contacts may be configured to urge at least one UV LED toward the proximal end of the light pipe. Among other things, the one or more of the conductive contacts may be a spring contact.

The disinfection chamber may include a main section and a submodule that are removably couplable. The light pipe may extend through a chamber wall of the submodule. The method may thread the submodule with the main section. To that end, a portion of the submodule may be threaded, and a portion of the main section may be complementarily threaded.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In illustrative embodiments, a light pipe30directly communicates ultraviolet (UV) light from a light-emitting diode (LED)40into a chamber12of a UV reactor10. Because the light from the LED40is transmitted into the chamber12via the light pipe30, some or all the surfaces (including a light pipe wall22through which the light pipe30extends) of the reactor10may be UV reflective (e.g., formed from reflective materials and/or coated with reflective material). This is in contrast to prior art methods that have a UV transmissive window coupled between the LED40(or other UV light source) and the chamber12. As another benefit, the light pipe30acts as a heat sink that draws heat away from the LED40. Specifically, the light pipe30is cooled by the fluid in the chamber12. The cooling effect of the heat sink may allow the LED40to operate at or above its maximum rated power. Details of illustrative embodiments are discussed below.

FIG.1Aschematically shows a UV reactor10for disinfecting fluid in accordance with illustrative embodiments of the invention. The UV reactor10has an inlet14through which fluid enters a chamber12(also referred to as a flow cell12of the reactor10). The inlet14may be coupled to a fluid source (e.g., water line that provides drinking water). At the other end of the UV reactor10is an outlet16through which fluid exits the chamber12(e.g., towards a faucet). While illustrative embodiments depict the outlet16and inlet14as being on opposed sides of the chamber12, it should be understood that the inlet14and the outlet16may be oriented anywhere on the UV reactor10. For example, the inlet14and/or the outlet16may be positioned on the sidewall22of the reactor10.

As the fluid flows through (e.g., from the inlet14to the outlet16), or is stagnant in, the chamber12, UV-emitting LEDs40disinfect the fluid. To that end, one or more of the above noted LEDs40are each coupled to a respective light pipe30that efficiently transfers the UV radiation into the chamber12. The LEDs40may be arranged outside of the chamber12and along the exterior of the sidewall22(e.g., spaced along a longitudinal axis13of the reactor10). Additionally, or alternatively, the LEDs40may be positioned on an end surface23. In some embodiments, the LEDs40may constantly be powered on. In some other embodiments, the LEDs40may be triggered by fluid flow through the chamber12. Additionally, or alternatively, the LEDs40may be periodically powered on or activated. Illustrative embodiments may use a variety of LED40dosing protocols, such as those described in U.S. Patent Application No. 62/891,503, which is incorporated herein by reference in its entirety.

FIG.1Bschematically shows a close-up view of one of the light pipes30coupled with one of the LEDs40in accordance with illustrative embodiments of the invention. The light pipe30has a distal end32and, opposite the distal end32, a proximal end34coupled (e.g., using attachment material48, such as a UV resistant adhesive) to or more UV LEDs40. In illustrative embodiments, at least a portion of the distal end32of the light pipe30extends into the reactor chamber12of a UV reactor10(shown inFIG.1), such that light from the UV LED40exits the distal end32and treats the fluid within the chamber12. While illustrative embodiments describe that the LED40is coupled to the proximal end34of the light pipe30, it should be understood that in some embodiments, the LED40may be formed integrally with the light pipe30and/or inside the light pipe30.

The light pipe30also has the central section36disposed between the proximal end34and the distal end32. The central section36is configured to transmit the UV light emitted from the UV LED40to the distal end32of the light pipe30. Accordingly, the central section36may have UV reflective material configured to prevent and/or reduce the amount of the UV light escaping and/or being absorbed prior to entering the chamber12. For example, the central section36of the light pipe30may be hollow and have a central section wall37with an inner surface (not visible). The inner surface of the central section36wall may be coated with a UV reflective material. Additionally, or alternatively, the central section36wall may be formed from UV reflective material. In some other embodiments, the central section36may be solid rather than hollow. For example, the central section36may have an inner portioned formed from a UV transmissive material, and an outer portion formed from a UV reflective material. Advantageously, in illustrative embodiments the central section36prevents or mitigates the loss of UV light delivered into the chamber12as a result of absorption and/or united transmission outside the chamber12.

In illustrative embodiments, the light pipe30is formed from a material with a refractive index that is relatively high. For example, in some embodiments, the refractive index of the light pipe, or at least a portion thereof (e.g., the portion adjacent the LED40through which the UV-light enters the light pipe30), has a refractive index of between about air (n=1) and about AlN (n=2.3 to 2.6 in the wavelength range of 300 nm to 220 nm). In illustrative embodiments, the high index of refraction makes it easier to couple radiation from the LED40into the light pipe30without losses due to reflection at the interface between the LED40and the light pipe30.

As noted above, the light pipe30and the LED40may be coupled using the attachment material48(e.g., an adhesive). In various embodiments, the attachment material48has an index of refraction between those of the light pipe30and the UV LED40. Preferably, the attachment material48is UV transmissive and UV stable. Advantageously, the attachment of the UV LED40to the light pipe30efficiently couples the UV light from the UV LED40into the light pipe30. The light is subsequently efficiently transmitted from the light pipe30(e.g., via one or more textured or roughened surfaces), thereby minimizing the opportunity for the light to reflect back to the UV LED40where it might be absorbed. Thus, illustrative embodiments efficiently treat fluid while minimizing loss of UV light via absorption. Although illustrative embodiments refer to textured or roughened surfaces of the light pipe30, it should be understood that some embodiments may have some or all of the surfaces described herein not textured and/or not roughened.

In some embodiments, the attachment material48may be silicone-based, and may include, for example, Deep UV-200 available from Schott North America, Inc. of Elmsford, N.Y. In other embodiments, the attachment material48may include a fluorinated polymer such as polytetrafluoroethylene (PTFE), e.g., Optical PTFE (available from Berghof Fluoroplastic Technology GmbH of Eningen, Germany), Teflon AF (available from DuPont®), or Cytop® (a polymerized perfluoro(4-vinyloxy-1-butene), available from Asahi Glass Company). In various embodiments, the attachment material48may include a silica-based polymer.

The distal end32of the light pipe30may be shaped to direct the light in one or more directions and/or focus the light from the UV LED40. For example, at least a portion of the distal end32may be convexly curved to be substantially hemispherical, conical, frustoconical, or cylindrical. It should be understood that these shapes are merely exemplary, and that illustrative embodiments are not limited thereto.

Although the maximum of the distal end32is shown as being approximately the same as that of the proximal end34and portions36of the light pipe30therebetween, this is not intended to limit various embodiments of the invention. For example, the diameter of the distal end32diameter (or other lateral dimension, such as width) may be larger than that of the proximal end34and/or one or more portions of light pipe30disposed between the distal end32and the proximal end34. As shown, various portions of the light pipe30may be substantially cylindrical and straight. However, one of skill in the art understands that the light pipe30may have other shapes (e.g., a substantially rectangular cross section) and/or curvature.

At least a portion of the light pipe30may be roughened or otherwise textured to enhance out-coupling of light from the UV LED40from the light pipe30. Preferably, the distal end32may be roughened or textured. In various embodiments, the roughening may be in a predetermined pattern such that a larger fraction of the light is emitted from such portions of the light pipe30. In various embodiments, only one or more portions (or even all) of the surface of the distal end32is roughened, such that the light is substantially only out-coupled from the distal end32. In other embodiments, one or more other portions of the light pipe30are roughened such that at least a fraction of the light is emitted (e.g., laterally) from the light pipe30. For example, the light pipe30may be roughened along at least a portion of the light pipe30, where the roughness (and thus amount of out-coupled light) increases along the length of the light pipe30toward the distal end32. However, in some embodiments, the light pipe30is not roughened and/or textured. In various embodiments, one or more portions of the light pipe30(e.g., one or more portions not textured or roughened for light transmission) may be coated with a material reflective to UV light to facilitate confinement of the UV light within the light pipe30. For example, one or more portions of the light pipe30may be coated with aluminum and/or PTFE. In various embodiments, PTFE may be utilized due to its compatibility with a wide range of fluids that may be treated within the UV reactor10.

Unlike visible LEDs, UVC LEDs40are difficult to encapsulate. The light emitting portion of a visible LED is typically plastic and is not capable of withstanding UVC exposure without rapidly being damaged. To the inventors' knowledge, there are no commercial UVC LEDs available that have a light emitting portion which could be inserted into a chamber. Commercially available UVC LEDs either have a quartz window over the light emitting portion or have a bare semiconductor surface. In addition, the plastic portion of the light emitting portion of a typical LED is a poor thermal conductor. Accordingly, illustrative embodiments of the invention may form the light pipe30from high thermal conductivity transparent mediums (e.g., sapphire). Additionally, illustrative embodiments may minimize the thickness of the material48used for the attachment of the light pipe30. Sapphire, for example, is transparent to UVC radiation, and generally does not degrade with long term exposure. Furthermore, sapphire has a thermal conductivity of approximately 35 W/m-K, which is at least 10× (more typically, 100×) higher than a molded plastic encapsulant for a standard LED.

Furthermore, typical sealing materials (e.g., between the LED and the inside of the chamber12) degrade and fail under UVC irradiation, which may cause the disinfection reactor chamber12to leak. Illustrative embodiments may use soft PTFE O-rings and/or seals that are resistant to UV (e.g., UVC radiation). The irradiance that these materials may be exposed to is high (e.g., up to 10 W/cm2 which is large compared to other UVC light sources). Inorganic materials like sapphire and quartz (UVC grade which means that UVC absorbing impurities have been removed) are more stable. Some embodiments may include sealing materials formed from fluorochemicals, like PTFE, which is also stable and UVC resistant.

In illustrative embodiments, the light pipe30may be formed from sapphire. Additionally, or alternatively, the light pipe30may be formed from one or more rigid inorganic materials such as quartz, or fused silica. The light pipe30may also be formed from other materials, such as materials having an index of refraction greater than 1.3 and/or that are transparent and stable during exposure to high intensity short-wavelength UV radiation.

In various embodiments, the diameter (or other lateral dimension such as width) of at least the proximal end34(and, in various embodiments, one or more other portions of the light pipe30) is selected to be approximately the same, or slightly larger (e.g., approximately 5% larger, approximately 10% larger, or approximately 25% larger) than the lateral dimension of the UV LED40, in order to minimize the thermal resistance of the light pipe30. For example, the lateral dimension of the light pipe30may be at least approximately 3 mm, at least approximately 4 mm, at least approximately 5 mm, or at least approximately 10 mm, and/or may be at most approximately 20 mm, approximately 15 mm, approximately 10 mm, approximately 5 mm, or approximately 4 mm.

The thermal resistance of the light pipe30may also be controlled (e.g., minimized) via selection of the length of the light pipe30(i.e., the dimension extending from the proximal end34to the distal end32). For example, the length of the light pipe30may be at least approximately 3 mm, at least approximately 4 mm, at least approximately 5 mm, or at least approximately 10 mm, and/or may be at most approximately 20 mm, approximately 15 mm, approximately 10 mm, approximately 5 mm, or approximately 4 mm. In some embodiments, the distal end32may be positioned so that it does not extend internally beyond the wall22of the reactor10. For example, the distal end32may be flush with the inner surface of the light pipe wall22.

The reactor10may be embodied in a small device. The inventors recognized that the surface area of the aperture through which the light pipe30passes may take up a disproportionately high amount of the internal surface area of the chamber12. For example, some prior art apertures known to the inventors may take up to 30-50 percent of the total surface area of the chamber12. Undesirably, this significantly reduces the amount of surface area of the chamber12that can reflect incoming UV light, adversely affecting uniform fluid treatment.

Accordingly, as described in U.S. Patent Application No. 62/836,793, which is incorporated herein by reference in its entirety, illustrative embodiments of the invention may minimize the size of the aperture relative to the overall surface area of the interior walls of the chamber12.

A person of skill in the art understands that illustrative embodiments of the invention may provide a number of advantages. For example, UVC LEDs40preferably are kept cool (e.g., ideally close to room temperature) during operation. Typically, the UVC LEDs40are heat sunk by extracting heat out of the back of the package42. However, heat sinks are typically larger than the LED40and may add substantial cost. Illustrative embodiments advantageously extract heat from the UVC LED40out of the same surface as the radiation emission surface, and use the fluid being disinfected as the heat sink. Accordingly, illustrative embodiments may operate without a traditional heat sink arrangement, which extracts heat sink from the rear of the LED40(i.e., opposite direction of light emission). The standard heat sink arrangement requires a costly LED mounting arrangement. For instance, a printed circuit board (PCB) with metal core (i.e., for heat sinking an LED), may cost 10× what a standard (FR4) PCB costs. This metal-core PCB must then also be heat sunk; either to the ambient at additional cost or back to the fluid with additional complication and cost. Accordingly, some embodiments advantageously avoid the use of the traditional heat sink mounting configuration.

FIG.2Aschematically shows a perspective view of a UV LED40in accordance with illustrative embodiments of the invention.FIG.2Bschematically shows a plan view of the back surface of the UV LED40shown inFIG.2A. As shown, the UV LED40may include one or more LED chips (packaged or unpackaged)44mounted on a submount or substrate package42. The LED40may be surface mounted (i.e., placed directly) onto the surface of a printed circuit board54(e.g., seeFIG.2C). In various embodiments, the UV LED40is configured to emit UV light, e.g., light within at least a portion of the wavelength range of approximately 100 nm to approximately 320 nm. In various embodiments, the UV LED40may also include one or more other electronic components46(e.g., a voltage regulator, such as a Zener diode). The electronic component46may protect the LED chip44from short circuits or electrostatic discharge (ESD) events. In various embodiments, the electronic component46may include one or more avalanche breakdown diodes and/or one or more silicon-controlled rectifiers. In various embodiments, the electronic component46may include a resistor and one or more diodes; for example, the resistor may be electrically connected in series with the one or more diodes.

FIG.2Aalso schematically shows the UV LED40on the substrate package42. The package42may include one or more plastics (e.g., part of a lead frame package), such as polyphthalamide (PPA) and/or one or more ceramics, such as aluminum nitride and/or alumina. In various embodiments, one or more portions of a surface of the package42may be coated with a material reflective to UV light (e.g., aluminum or PTFE) and/or that is electrically and/or thermally conductive (e.g., one or more metals).

As shown inFIG.2B, the back side of the UV LED40may have thereon one or more contacts for electrical coupling to the UV LED40. For example, as shown inFIG.2B, the back side of UV LED40may have an anode contact56and a cathode contact56. Such contacts56may electrically couple to the LED chip44through the thickness of the package42, e.g., through one or more vias or other connectors disposed within the package42. As also shown inFIG.2B, the back side of the UV LED40may have a thermal plate for further dissipation of heat generated by the UV LED40. The thermal plate may therefore include one or more thermally conductive materials (e.g., one or more metals, e.g., copper, gold, aluminum, etc.).

In illustrative embodiments, the UV LED40is formed with an aluminum nitride (AlN) substrate with one or more quantum wells and/or strained layers, including AN, gallium nitride (GaN), indium nitride (InN), or binary or tertiary alloy thereof. The UVC LED40preferably has a substrate and/or device structure resembling those detailed in U.S. Pat. No. 7,638,346, filed on Aug. 14, 2006, U.S. Pat. No. 8,080,833, filed on Apr. 21, 2010, and/or U.S. Patent Application Publication No. 2014/0264263, filed on Mar. 13, 2014, the disclosures of which are incorporated herein, in their entireties, by reference. As known to those of skill in the art, the specific semiconductor materials and layer structure of the UV LED40may be selected so that a desired specific wavelength (or wavelength range) of light is emitted by the UV LED40. In various embodiments of the invention, the UV LED40may be a well know, commercially available device, such as the KLARAN™ UV LED, distributed by Crystal IS, Inc. and Asahi Kasei.

In various embodiments, the UV LED40is also urged toward and/or attached to the proximal end34of the light pipe30by electrical contacts56that are also utilized to supply power to the UV LED40. For example, one or more spring contacts may be utilized that each make contact to one of the back-side contacts of the UV LED40. In various embodiments of the invention, the use of such spring contacts is facilitated because no additional thermal management (e.g., heat sinking) is needed on the back side of the UV LED40; instead, heat is extracted from the UV LED40via the light pipe30itself (and, in various embodiments, from the light pipe30to the fluid being treated).

FIGS.2C and2Dschematically show an electrical-connection scheme for the UV LED40in accordance with illustrative embodiments of the invention.FIG.2Cschematically show a cross-sectional schematic depicting the UV LED40attached to a central section36of the light pipe30via an attachment material48(note that the remainder of the light pipe30, including the distal end32, is not shown inFIG.2C). As shown, power is supplied to the UV LED40via spring contacts50that extend through and are electrically isolated from a base52. The base52may be formed from one or more suitably rigid materials, e.g., metals such as aluminum. In various embodiments, the base52may be thermally conductive. As shown, the base52may be electrically and/or mechanically attached to a printed circuit board54containing electrical contacts56that themselves are electrically coupled to a source of power for UV LED40(e.g., a power supply, not shown).

FIG.2Dschematically shows more details of the spring contacts50in accordance with illustrative embodiments of the invention. As shown, each spring contact50may include a contact pin58and a spring60that is configured to urge the contact pin58toward the UV LED40and make electrical contact thereto. In various embodiments, electrical and mechanical contact between the contact pins58and the electrical contacts of UV LED40is made only via the spring force imparted by the springs60. That is, in some embodiments of the invention, no other coupling material (e.g., solder, adhesive, etc.) may be present between the contact pins58and the electrical contacts of UV LED40. As utilized herein, the term “spring” includes any elastic entity, member, or object that reversibly stores mechanical energy. Exemplary springs include coil springs, wave springs, disc springs, leaf springs, Belleville springs (i.e., coned disc springs), and/or bellows.

FIG.3schematically shows a partial schematic of a UV reactor10in accordance with various embodiments of the present invention. As described previously, the reactor chamber12has liquid flowing therethrough to be treated by UV light. As opposed toFIG.1, inFIG.3, the light pipes30are generally parallel with and spaced transverse to the longitudinal axis13(shown in dashed lines). Furthermore, the light pipe wall22includes the end surface23rather than the sidewall18. The fluid flows into the reactor chamber12via the fluid inlet14and exits the reactor chamber12after treatment via the fluid outlet16. The reactor chamber12may have at least one sidewall18and the light pipe wall22through which one or more light pipes30penetrate into the reactor chamber12. In some embodiments, the sidewall18may also be the light pipe wall22(e.g., as shown inFIG.1). Additionally, or alternatively, illustrative embodiments may include more than one light pipe wall22(e.g., an end surface and a sidewall18).

The reactor chamber12may include one or more materials compatible with the fluid to be treated, e.g., quartz. Accordingly, the reactor chamber12, or a portion thereof, may be substantially transparent to UV light. The sidewall18and/or the light pipe wall22may be coated (e.g., on an outside surface) with a material substantially reflective to the UV light emitted from the light pipe30, e.g., aluminum and/or PTFE. The coating may be diffusively reflective or specularly reflective, and thereby facilitates confinement of the UV light from the light pipe30within the reactor chamber12—in various embodiments, the fluid is more efficiently disinfected via multiple interactions with the UV light (e.g., caused by reflections from the sidewall18and/or the light pipe wall22).

In various embodiments, the UV reactor10is a flow-through reactor in which the fluid flows from the fluid inlet14to the fluid outlet16during treatment by UV light. In other embodiments, the UV reactor10may be a batch reactor in which fluid is introduced into the reactor chamber12, treated by UV light, and then extracted through the fluid outlet16after all or a portion of the illumination by UV light.

One or more light pipes30may be at least partially inserted into the reactor chamber12via apertures (also referred to as openings) defined in the light pipe wall22. After the light pipe30is inserted, a liquid-tight seal is preferably formed between the light pipe30and the light pipe wall22to prevent fluid leakage. For example, an O-ring may be disposed within the opening and may engage with the outer surface of the light pipe30after insertion thereof. The O-ring may include PTFE. Other embodiments may use silicone or other fluid-tight sealants.

While in some embodiments each light pipe30may be individually positioned into an opening in the light pipe wall22, in other embodiments, multiple light pipes30are coupled, at their proximal surfaces120, to a shared substrate (e.g., the printed circuit board54) and extending through openings in the light pipe wall22. The shared substrate may then contact the light pipe wall22. The light pipes30may be coupled to the substrate via, e.g., soldering or an adhesive (e.g., a conductive adhesive).

As mentioned above, one or more portions32-36of the light pipe30may be roughened or textured to enhance light extraction from such surfaces, thereby directing the UV light in particular directions and/or locations within the reactor chamber12. A plurality of the light pipes30may be roughened such that the light from the light pipes30is configured to focus on a particular area and/or along a particular direction within the reactor chamber12. For example, one or more portions of the distal end32of each of the light pipes30may be roughened such that the light from the light pipes30is directed toward a central axis13of the reactor chamber12and/or toward the sidewall18. In various embodiments, the light from the light pipes30may be directed toward the fluid outlet16.

Furthermore, in some embodiments the emission surface of the LED40may be roughened. Illustrative embodiments may match the index of the light pipe30to the LED40emission surface, such that more of the emitted radiation is captured into the light pipe30without being reflected. The roughening of the LED40emission surface may help in some situations (e.g., where there is still a large index mismatch and the roughening helps scatter radiation that was outside the acceptance cone into the acceptance cone and, thus, into the light pipe30).

FIG.4schematically shows a cross-section of a portion of another embodiment of the reactor chamber12in accordance with illustrative embodiments of the invention. As shown, the light pipe30has a distal end32disposed within the reactor chamber12and that may be shaped as, for example, a hemisphere, a partial sphere, or a lens. The diameter or other lateral dimension of the distal end32may be larger than the central section36of the light pipe30. The central section36may be partially or completely disposed within the light pipe wall22. Thus, in some embodiments, the length of the central section36is less than or approximately equal to the thickness of the light pipe wall22(or the sidewall18).

The small length of the central section36may advantageously minimize the thermal path of heat conducted away from the UV LED40via the light pipe30. The light pipe30may be sealed within the light pipe wall22via, e.g., one or more O-rings that provide a fluid-tight seal. In various embodiments, as shown inFIG.4, the light pipe wall22may be shaped or milled to enable the UV LED to be at least partially disposed within the light pipe wall22. Such configurations may also enable the advantageous minimization of the length of the central section36. As discussed above, the sidewall18, end wall23, and/or the light pipe wall22may include (e.g., be coated with), and/or be formed from, one or more materials diffusively or specularly reflective to UV light.

In various embodiments, the central section36is a portion of or window defined within the material of the light pipe wall22. For example, the central section36may be defined by an opening in a reflective coating disposed over portions of the end surface. In such embodiments, the UV LED40may be attached directly to the window in the central section36. The distal end32, mounted within the reactor chamber12, may be used to extract and focus the light from the UV LED40.

In various embodiments, the opening in the light pipe wall22through which the light pipe30may initially be sufficiently large to accommodate insertion of the larger distal end32(as shown inFIG.4). After insertion, any remaining gaps or empty space within the opening, given the smaller-diameter central section36, may be filled with a potting material that is compatible with the fluid to be treated and, in some embodiments, reflective to UV light. For example, the potting material may include a fluoropolymer, such as PTFE.

In various embodiments, the opening in the light pipe wall22may include a compliant seal that is expandable to accommodate insertion of the distal end32and, thereafter, compresses against the central section36to form a fluid-tight seal. For example, the opening may have a diameter or other lateral dimension that is slightly smaller than that of the distal end32and/or central section36but that is compliant (e.g., having an inner lining including a compliant material such as expanded PTFE) and seals against the central section36after insertion of at least a portion of the light pipe30.

FIG.5schematically shows an alternative embodiment of the reactor10. Specifically, the reactor chamber12is broken into a main portion coupled with a submodule62. The submodule62includes one or more light pipes30extending through its wall. Furthermore, the submodule62may be modularly mateable with the remaining section of the UV reactor10. For example, as shown inFIG.5, the submodule62may include an internally UV-reflective light pipe wall22of the reactor chamber12and may feature a threaded edge64to replaceably mate and seal with the remaining portion of the reactor chamber12. Such embodiments facilitate the replacement and/or servicing of components associated with the light pipes30.

FIG.6shows a process of disinfecting fluid in accordance with illustrative embodiments of the invention. It should be noted that this method is substantially simplified from a longer process that may normally be used. Accordingly, the method shown inFIG.6may have many other steps that those skilled in the art likely would use. In addition, some of the steps may be performed in a different order than that shown, or at the same time. Furthermore, some of these steps may be optional in some embodiments. Accordingly, the process100is merely exemplary of one process in accordance with illustrative embodiments of the invention. Those skilled in the art therefore can modify the process as appropriate. Finally, although this process is discussed with regard to activating a single UV LED40, the process100ofFIG.6can be expanded to cover using a plurality of UV LEDs40at the same time.

The process100begins at step102, which provides the fluid treatment system. As described previously, the fluid treatment system may include the reactor chamber12having the inlet14, the outlet16, and the UV LED40coupled with the light pipe30extending through a wall of the chamber12. In some embodiments, the reactor chamber12has the main section and the submodule62, and the light pipe30extends through the wall of the submodule62.

The process proceeds to step104, which couples the main section and the submodule62. The main section and the submodule62may have threads64that can be threadably engaged to couple the sections together. When the sections are coupled, the distal end32of the light pipe30is within the chamber12, and the proximal end34and the LED40are outside of the chamber12.

The process then proceeds to step106, which flows fluid through the reaction chamber12. The fluid may enter the chamber12from the inlet14and exit the chamber from the outlet16. At step108, the UV LED40is activated to emit UV light. Preferably, the light is UVC light having a wavelength of between about 100 nm and about 280 nm. Furthermore, the LED may be activated according to a dosing schedule described previously.

At step110, the UV light emitted by the LTV LED40travels along the light pipe30(e.g., along the central section36) and is transmitted into the fluid in the chamber12through the distal end32. In some embodiments, the high refractive index of the material making up the light pipe30(e.g., sapphire) may cause the UV radiation to be totally internally reflected (i.e., unless it is approaching the surface of the light pipe30at close to a normal angle). Roughening the surface (e.g., at the distal end32) may stop this total internal reflection and cause a portion of the radiation to escape even if it is outside the escape cone. The distal end32of the light pipe30may be textured or roughened to enhance UV transmission. To further facilitate transmission, the distal end32of the light pipe30may have a larger diameter than the central section36. The process may then return to106and flow fluid as often as the end-user desires. As described previously, the fluid cools heat drawn from the LED40to the light pipe30. Illustrative embodiments thus may use the fluid to advantageously cool the light pipe30. At some point the fluid may stop flowing (e.g., the user no longer requests that fluid be dispensed) or fluid may continuously flow through the reactor. Either way, the process may move to the next step at any time (e.g., when the fluid stops flowing, or while fluid continues to flow).

Optionally, at step112, the submodule62having the light pipe30may be uncoupled from the main section (e.g., when the LED40output power has been degraded). At step114, the LED40coupled to the light pipe30may be replaced, and the submodule62may be coupled to the main section.

Disclosed embodiments, or portions thereof, may be combined in ways not listed above and/or not explicitly claimed. In addition, embodiments disclosed herein may be suitably practiced, absent any element that is not specifically disclosed herein. Accordingly, the invention should not be viewed as being limited to the disclosed embodiments.

The embodiments of the invention described above are intended to be merely exemplary; numerous variations and modifications will be apparent to those skilled in the art. Such variations and modifications are intended to be within the scope of the present invention as defined by any of the appended claims.