UV-LED LIQUID TREATMENT SYSTEMS AND METHODS

Abstract

The present invention utilizes an array of light-emitting diodes (LEDs) (UV-LEDs) emitting in the ultraviolet spectrum to disinfect large water streams. The irradiation chamber can utilize high-power density UV-LEDs arranged in a planar array to irradiate the fluid flowing through a cylindrical irradiation chamber formed from a transparent material. The transparent irradiation chamber can be enclosed within a secondary optical chamber constructed from a reflective material or coated or covered with a reflective material. A vortex generator can be placed in the cylindrical irradiation chamber, creating a laminar flow region that spirals the flow along the length of the irradiation chamber, resulting in uniform UV exposure, or irradiance, between hot spots and dark areas.

Description

[Technical Field]

[0001] The present invention relates generally to the use of ultraviolet (UV) light for disinfecting and treating fluids, and more particularly to the use of arrays of light emitting diodes (LEDs) emitting in the ultraviolet spectrum (UV-LEDs) for disinfecting large volumes of water streams. [Background technology]

[0002] The liquid composition can be irradiated with ultraviolet light in-line, for example, within a pipe, tube, channel, or similar device for transporting a liquid stream from one process, tank, or vessel to another. Such internal UV light devices are well known in the food and water treatment industries. Patents and patent publications describing such fluid radiation treatment systems include U.S. Pat. Nos. 4,317,041, 4,482,809, 4,872,980, 5,006,244, 5,418,370, 5,539,210, 5,846,437, 5,866,910, 5,994,705, 6,015,229, 6,916,452, 7,166,850, 7,390,225, 7,695,675, 7,985,956, 8,167,654, and 8,766,211, the disclosures of which are incorporated herein by reference in their entireties. Turbidity is a measure of suspended solids in a composition and can affect microbial kill by preventing pathogens from contacting UV light. Thus, a more turbid composition will require substantially higher dosages to achieve desired microbial kill compared to a less turbid composition.

[0003] Equipment and systems for disinfecting liquids using UV light are divided into several categories based on the system's flow rate. For example, point-of-use systems are small systems typically installed near the fluid's exit point (such as a water disinfection system installed at a single faucet). These systems have a low fluid flow rate through the system and typically do not require a large amount of UV radiation to disinfect the fluid. Point-of-entry systems have a high flow rate and are used for multiple distribution points (such as water distributed to multiple faucets and all appliances). Industrial systems are typically used for commercial applications, such as water used in factory processes. Municipal systems are the largest systems and are used before distributing drinking water to a community. The following table characterizes the flow rate of a drinking water or cooling water system and the radiant UV power required to disinfect the water.

[0004] [Table 1]

[0005] There are many fluid disinfection applications where the ultraviolet transmittance (UVT) of the fluid is less than 80%, requiring higher radiant UV power to achieve disinfection of the fluid. These fluids include pharmaceuticals, fruit juices, mining water, and wastewater. Similarly, there are photochemical applications where similar scaling principles apply. Disinfection wavelengths vary but are generally in the UVC region between 200 nm and 300 nm.

[0006] Historically, most UV (light) sources were manufactured using mercury lamp technology. However, over the past two decades, semiconductor-based planar UV sources have been developed. The most commercialized examples are UV-LEDs, i.e., light-emitting diodes (LEDs) that emit in the ultraviolet spectrum, but UV laser diodes, microplasma lamps, and electroluminescent devices are also alternatives. The power levels and efficiencies of these planar sources are much lower than those of mercury-based sources, specifically, the typical electrical conversion efficiencies of 15% and 30% for medium- and low-pressure lamps, respectively.

[0007] For example, while UVC LEDs are rapidly becoming commercially available, current commercial devices have electrical conversion efficiencies of less than 10% and typically require proper cooling, otherwise the LED's lifetime, output, and reliability are significantly reduced. In contrast, mercury vapor lamps operate well at higher temperatures but experience reliability issues in very cold conditions. Mercury vapor lamps also emit heat in the same direction as they emit photons. This is not the case for semiconductor-based UV sources, which emit heat from the device's electrical contacts, which are typically connected through the backside of the surface-mount package. This results in a UV source that emits heat from the electrical connection side and emits UV light from a different emitting surface, typically the top surface of the surface-mount package.

[0008] UVC LED (light) sources currently have a higher radiant (linear) power density compared to mercury lamps. This power density can be calculated by dividing the radiant power by the surface area of ​​the emitting surface of the light source. For UVC LEDs, this is the surface area of ​​the top of the package, while for mercury lamps, the surface area of ​​the quartz is used in the calculation.

[0009] When semiconductor-based UV sources are used in industrial or utility-sized UV systems, higher power densities and cooling requirements present both design opportunities and challenges. While kilowatts of heat must be removed from the UV source, placing the UV source in a smaller footprint and utilizing features such as flow conditioners (vanes, baffles, constrictions, flares), reactor length, and reflectors can increase the efficiency of the UV fluence delivered to the fluid.

[0010] The use of localized arrays of planar light sources (whose total surface area substantially covers less than the total external surface area of ​​the irradiation chamber) presents a challenge for monitoring UV flux within a reactor. Public and industrial systems critical to protecting health and process viability often require monitoring the level of UV flux within the reactor and, if UV is too low, signaling an alarm to a control system to stop the process and replace the UV source. This requirement becomes even more complex when the fluid within the reactor has low UV transmittance (i.e., high fluid turbidity) or when multiple planar arrays are placed on different tangents around the reactor. The sensor location depends on the array tangent, the array length, and the reactor location.

[0011] UV reactors operate via the photochemical effect and are therefore subject to the first law of photochemistry, the Grotthuss-Draper law. For a reaction to occur, a photon must be absorbed by the target species. Therefore, the basic optimization of reaction efficiency requires maximizing the absorption rate of UV radiation (source) delivered to the fluid being treated. In the simplest case, the reaction rate (k) is determined by the volume (V, m 3 ) is proportional to the transmitted power (Pb, W): that is, k ∝ P b / V.

[0012] Specifically, for UV disinfection reactors, where this method is more commonly applied through exposure to fluids, the degree of reaction is determined by the decay coefficient e(α n,m-1), which must include the fluence rate H' e ,W m -2 ):H' e =P b / (α n V).

[0013] By integrating the above over a fixed time, the flow rate (Q,m 3 s -1 ) or as a function of absorbed radiant energy (Wb, J), -2 ) is obtained. Disinfection reactions typically produce a log-linear inactivation effect per unit fluence delivered, so the reaction rate is often not proportional to the fluence, but there is always a positive correlation: H e =P b / (α n Q)|| H e =W b / (α n V).

[0014] The above formula applies when the "reagent" is present in excess, and therefore the reaction rate is constant over the observation period, and when the fluence rate is uniform throughout the volume being treated. These conditions are usually met for short periods of time and small evaluation volumes. When larger volumes are considered, physical reactor design factors such as divergent radiation sources and the photochemical properties of the treated fluid (attenuation according to the Beer-Lambert law) can affect the fluence rate (H e Fluence, or radiant exposure, is equivalent to the radiant energy received by a surface per unit area, or the irradiance of a surface integrated over time.

[0015] Thus, the distribution of fluence rates across (through) a quiescent fluid results in a distribution of reaction rates and hence a distribution of "product" formation across the volume of the fluid. For first order reactions, the volume-averaged concentration of "product" is determined by the volumetric radiation (J m -3), this may still be an optimized reaction if the end products are mixed. However, most applications exhibit either first-order kinetic saturation (e.g., due to complete conversion in overexposed regions), inherently higher-order kinetics (e.g., the log-linear inactivation response of most microorganisms), or deleterious or reverse processes (e.g., decomposition of the "product" in dynamic equilibrium). In these cases, the distribution and magnitude of the fluence transmitted through the fluid can have a significant impact on reaction efficiency, and therefore directly affect operating costs.

[0016] Considering that the management of operating conditions (fluid absorbance, temperature, turbidity, chemical / photochemical activity, etc.) is separate from the reactor design, there are essentially four strategies for increasing the efficiency of photochemical reactors. These strategies can be applied independently or in concert, and in various ways, in any given application. (i) Selecting more preferential spectral characteristics of the radiation source to maximize the reaction rate through a higher quantum yield (Φ(λ),-); (ii) Maximizing optical coupling between the radiation source and the target material, P b →P0; (iii) maximizing the uniformity of the fluence rate distribution throughout the volume of the irradiated fluid; and (iii) Volumetric mixing is introduced to optimally move each volume element of fluid through each volume element in space with a non-zero fluence rate.

[0017] Considering the preferred spectral characteristics of a radiation source, numerous radiation sources exist, and a radiation source can be selected based solely on those spectral characteristics. Additionally, other non-limiting characteristics, such as material composition, durability, price, electronic efficiency, power density, and form factor, can also be considered. In particular, light-emitting diodes (LEDs) emitting in the ultraviolet spectrum (UV-LEDs) may have preferred characteristics for many photochemical applications. In particular, their spectral wavelength tunability (commercially available UV-LEDs are manufactured with peak wavelengths of approximately 230–400 nm), power density (radiant flux per unit area of ​​device footprint), and modularity (ability to be assembled into series-parallel arrays) make them suitable for photochemical reactors. The beneficial properties of LED sources are well known.

[0018] Considering the maximization of the optical coupling of the reactor, this is a positive expression (P by efficiently transferring the radiative flux from the source to the target fluid). b This can be described in either negative terms (maximizing the power loss through absorption by reactor elements other than the target fluid) or negative terms (minimizing power loss through absorption by reactor elements other than the target fluid). The former, called optical in-coupling, involves designing the environment around the radiation source to preferentially direct the radiation source into the reaction chamber containing the irradiated fluid (substance). This can be achieved through sophisticated technological means such as parabolic mirrors, "beam shaping," collimation, and refractive index matching, or through simpler approaches such as reducing the displacement of the irradiated object from the radiation source to neutralize divergence effects. In all of these approaches, the goal is to direct the radiation directly into the reaction chamber containing the irradiated fluid. Inefficient optical in-coupling can be considered a loss mechanism. In the second sense, once optical in-coupling is achieved, the goal is to maintain the radiant power within the target fluid. Since the speed of light is constant for a given medium, radiation is always moving. Therefore, the only way to maintain radiant power within a medium is by being absorbed by that medium (note the impact on photoactivity, consistent with the first law of photochemistry). However, the absorbance (m) for a particular medium within a photochemical reactor can vary.-1 ) is usually constant, which means that per unit length of propagation, only a certain fraction of the radiated power is absorbed.

[0019] Reactor designers can consider several options, including maximizing path length and maximizing absorption (radiant power retention), e.g., by increasing the dimensions of the reaction chamber; the placement of the radiation source relative to the reaction chamber or optical aperture; the size and location of the optical, hydraulic, or other apertures; and the selection of reaction chamber materials (taking into account their reflective, refractive, photochemical, or photoactive properties). Refractive index boundaries can be applied to take advantage of phenomena such as total internal reflection within the fluid. Similarly, highly reflective materials can be applied to portions of the reaction chamber (or even beyond transparent interfaces) to redirect radiation that might otherwise be lost from the system back into the target fluid. It should be noted that radiation absorbed by elements of the reactor / system that are not the target fluid or that otherwise have photoactive or photocatalytic properties constitutes a loss of optical coupling efficiency.

[0020] With regard to maximizing fluence rate uniformity, there are several means for manipulating the fluence rate distribution within the reaction chamber, including, but not limited to, optimizing the shape and size of the reaction chamber; optimizing the position of the radiation source relative to the reaction chamber; beam shaping or optical conditioning of the radiation emitted from the radiation source before it enters the reaction chamber; using reflective or diffusing elements to spread the radiation throughout the reaction chamber; and using an integral cavity approach to create multiple passes of the radiation along different paths through the fluid within the reaction chamber.

[0021] Considering the volumetric mixing of the irradiated process fluids, the fundamental goal is to neutralize the distribution of fluence rates across the reaction chamber. This is achieved by directing the fluids so that each streamline within the reaction chamber integrates a uniform fluence, delivering a uniform fluence throughout the flow. There will always be some degree of non-uniformity in fluence delivery. The obvious solution is to achieve an ideal mixing of the fluids (H') throughout the reaction chamber. e >0), ensuring that each volume element of the fluid is exposed to each region of the fluence rate field for an equal amount of time. Ideal mixing is primarily a theoretical upper limit and is rarely achieved in practice in reaction chambers. More complex designs may consider structured flow from the reactor inlet to the outlet. For example, among various flow concepts, there are linear laminar flow through reaction chambers with regular cross sections; swirling laminar flow through reactors with curved walls; turbulent flow around "sharp" boundaries within the reaction chamber; and turbulent flow due to disturbance and mixing in the boundary layer and central flow region. These fluid flow conditions can be achieved by manipulating the shape and size of the reaction chamber, introducing flow conditioning elements (e.g., baffles, constrictions, flares, vortex generators, static mixers, etc.), manipulating the flow rate through the reaction chamber using parallel processing streams, or other means.

[0022] Large-scale UV fluid treatment, such as municipal UV disinfection of drinking water, requires a very high flux of UV light. Inefficiencies in UV light generation result in significant heat generation, which must be removed to maintain device functionality. Municipal UV treatment systems are often required to be installed outdoors or in non-climate-controlled environments. For example, systems may be installed outdoors in the desert. Without control over the external environment, many heat removal methods can be unreliable. For example, using a fan to blow air over the system is ineffective if the ambient air is hot. Furthermore, systems that use fans are susceptible to flooding during rainstorms.

[0023] The preferred solution is to transfer the generated heat to the untreated process fluid. In typical drinking water treatment applications, if the process flow can somehow be placed in thermal contact with the UV-LED system, the process flow will be cool enough to effectively remove heat from the UV-LED system. Traditional mercury vapor valve UV disinfection systems already use the process flow itself to cool the valve. This is achieved by placing the mercury valve within a cylindrical, protective quartz tube. These quartz tubes then protrude from the section of process flow pipe designated as the UV disinfection chamber. As water flows through this pipe section, it passes around these quartz tubes, cooling the mercury valve and exposing it to UV light radiation from the mercury valve. The cylindrical profile of the mercury valve plays a key role in the practicality of this design.

[0024] UV-LED arrays are primarily planar in shape because it is inefficient to build high-power UV-LED systems within a cylindrical footprint. Furthermore, because UV-LEDs must be kept cooler than a mercury bulb, heat transfer through a protective quartz tube is insufficient to meet the cooling requirements of UV-LED arrays. Therefore, UV-LED arrays require a new approach to transfer heat from themselves to the process flow. The present invention provides various embodiments of devices and methods to accomplish this.

[0025] EP3461793 to Khan (hereinafter "Khan") discloses a water treatment application using a planar light source mounted outside a transparent reactor. However, the placement of UVC LED arrays, whether curved or even planar, creates a customized spatial flux distribution to generate a dose distribution. The present invention takes into account the high flux zones generated by planar light sources and instead optimizes the dose distribution using tailored flow paths and reactor length. Khan does not disclose how to solve the challenges of cooling and powering the planar array and associated power supplies, which are important when dealing with large arrays requiring multiple kilowatts of power.

[0026] McNulty's U.S. Patent No. 10,604,423 discloses cooling an LED array radially arranged around a UV-transparent tubular reactor. However, this invention employs a method of focusing UV radiation by collimating it radially around the reactor and directing the radiation along the longitudinal axis toward the center of the tube, concentrating the UV light there. This contrasts with the present invention, which does not collimate the UV and instead generates the highest UV flux outside the reactor's inner diameter, directly opposite the UV array. This is compensated for by using flow mixing elements that force the fluid through the high UV flux region, ensuring sufficient mixing over the length of the tube. The present invention also uniquely describes the use of mixing elements to induce rotational or vortex motion in the fluid upstream of the unit to ensure proper processing.

[0027] Nevertheless, improving commercial fluid processing with UV light remains of interest. The design of reactor hydraulics must overcome deficiencies in fluence rate uniformity not only in high-conversion reactions (e.g., disinfection measured as log reduction) but also in mass-transport-limited operations (such as those observed with highly absorbent fluids). Similarly, it is beneficial to provide a resilient design that can maintain high-efficiency operation over a wide range of fluid absorbances. This contrasts with applications where optimizing fluence rate field uniformity is the primary means of high-efficiency operation, because the fluence rate distribution is intrinsically related to and strongly dependent on the absorbance of the fluid under irradiation. Summary of the Invention

[0028] The present invention provides a reactor in which a process flow passing through a cylindrical reactor vessel (hereinafter referred to as an "irradiation chamber") made of a transparent material is irradiated with high-power-density UV-LEDs arranged in a planar array. Planar arrays offer significant advantages in simplifying the fabrication of the reactor and the thermal control and power supply of the UV-LEDs.

[0029] The transparent irradiation chamber may be enclosed within a secondary optical chamber constructed of, or coated or covered with, a reflective material. Such a design maximizes optical in-coupling by providing a reflective surface that redirects radiation from the diverging planar source (away from directly entering the irradiation chamber and processing flow) and recovers radiation that enters the irradiation chamber and passes through the transparent wall, serving a secondary role. This recovery of radiation back into the irradiation chamber reduces net optical out-coupling, thereby improving operational efficiency. The material providing the reflective surface preferably has a bulk reflectivity of 80% to 100% in the UV-C region emitted by the UV light source.

[0030] The present invention provides fluid treatment devices and systems for treating a process flow with ultraviolet (UV) light, which may include sterilizing the process flow.

[0031] The fluid treatment device includes a cylindrical irradiation chamber having an annular wall constructed from a UV light transmissive material, the annular wall having an outer surface, an inner surface, and first and second opposed open ends that define a treatment flow path having a centerline.

[0032] The fluid treatment device can include an inlet for treatment flow into a first open end of the irradiation chamber and an outlet from a second open end of the irradiation chamber.

[0033] The fluid treatment device also includes a planar array of ultraviolet light emitting diodes (LEDs) configured to emit UV light. The planar array of UV LEDs has a length along a centerline parallel to the centerline of the irradiation chamber and a width. Preferably, a normal to the planar array passes through both the centerline of the planar array and the centerline of the irradiation chamber.

[0034] UV light emitted from a planar array of UV-LEDs strikes an arc segment on the exterior surface along the length of the irradiation chamber and passes through the annular wall into the process flow channel.

[0035] In some embodiments, the width of the planar array of UV-LEDs is equal to or less than the outer diameter of the annular wall of the irradiation chamber.

[0036] In some embodiments, the area of ​​the planar array of UV-LEDs is less than 60% of the area of ​​the exterior surface of the irradiation chamber.

[0037] The fluid treatment device can include a light reflector covering a non-irradiated portion of the outer surface of the irradiation chamber that is not within the arc segment and that is not exposed to UV light directly emitted from the planar array of UV-LEDs. The light reflector reflects UV light that passes through the annular wall from within the treatment flow path back into the annular wall and then back into the treatment flow path.

[0038] In some embodiments, the light reflector comprises one or more reflective panels positioned opposite or over the non-irradiated portion of the exterior surface. The one or more reflective panels can be directly affixed to or positioned adjacent to the exterior surface of the irradiation chamber. In some embodiments, the light reflector can be a dry coating of a reflective film or paint applied directly to and adhered to the exterior surface of the irradiation chamber. In some embodiments, the non-irradiated portion of the exterior surface of the quartz wall can be patterned or etched to create a sub-wavelength reflector that reflects UV light back into the irradiation chamber.

[0039] The fluid treatment device may also include a heat exchanger configured to remove heat generated by the planar array of UV LEDs. In some embodiments, the one or more heat exchangers are configured to remove heat generated by the planar array of UV LEDs, and optionally, but preferably, also heat generated by one or more of a power supply unit and a control unit that power and control the operation of the planar array of UV LEDs.

[0040] In some embodiments, the fluid treatment device comprises an LED array module including a planar array of UV-LEDs and a heat exchanger, hi some embodiments, the LED array module also comprises a power supply for providing power to the planar array of UV-LEDs and optionally a control board for controlling operation of the UV-LEDs.

[0041] In some embodiments, the fluid treatment device includes a secondary chamber therein, the secondary chamber enclosing the irradiation chamber, the secondary chamber having inlet and outlet openings for accessing the first and second open ends of the irradiation chamber.

[0042] The secondary chamber also includes a first opening for mounting the LED array module, which in some embodiments is a rectangular flanged opening through which the planar array of UV-LEDs is exposed to the irradiation chamber.

[0043] In some embodiments, the fluid treatment device can include one or more second planar arrays of UV-LEDs and corresponding second heat exchange devices. In such embodiments, the second chamber can include a second flanged chamber on an opposite side of the first flanged opening.

[0044] In some embodiments, the second flanged opening is configured to orient the plane of the second planar array of UV-LEDs at an arc angle of 120 to 160 degrees relative to the plane of the first planar array of UV-LEDs.

[0045] In some embodiments, the heat exchange device comprises a cooling plate having a first cooling surface and an opposing second cooling surface, wherein the planar array of heat sinks for the planar array of UV-LEDs is thermally coupled to the first cooling surface and the power supply is thermally coupled to the second cooling surface.

[0046] In some embodiments, the fluid treatment device further comprises means for swirling the untreated treatment flow through at least one revolution over the discharge portion of the length of the irradiation chamber.

[0047] In some embodiments, the fluid treatment device includes a second planar array of UV-LEDs and a corresponding second heat exchange device.

[0048] The devices, water treatment systems, and methods of using the devices of the present invention are particularly suited for drinking water treatment, wastewater treatment, industrial process water treatment, and other applications requiring high flow rates of treated fluids. In preferred embodiments, each device can be configured to treat 15 to 750 cubic meters of water per hour. Preferably, each device can be configured to treat 30 to 500 cubic meters of water per hour. Most preferably, each device can be configured to treat approximately 250 cubic meters of water per hour.

[0049] In addition to treating and disinfecting water and water systems, the apparatus of the present invention can also be used in the industrial and commercial treatment of other liquids that may contain or be contaminated with pathogens, such as, but not limited to, beverages, cleaning solutions, cooking products, personal care products, etc.

[0050] The present invention also provides a water treatment system comprising a plurality of fluid treatment devices arranged in parallel, series, or a combination thereof.

[0051] The present invention provides a fluid treatment device for treating a process flow, the fluid treatment device comprising: a) a cylindrical irradiation chamber with a quartz wall constructed of a UV-light-transmissive material having an outer surface forming a process flow path; b) a planar array of ultraviolet light-emitting diodes (LEDs) disposed around only a portion of the exterior of the quartz wall of the irradiation chamber and configured to emit UV light that passes through the quartz wall; c) a UV-light-reflecting material covering the exterior of the quartz wall of the irradiation chamber not surrounded by the planar array of UV-LEDs and reflecting the UV light that passes through the quartz wall back into the process flow; and d) a heat transfer system configured to remove thermal energy from a heat-generating device including the planar array of UV-LEDs. In some embodiments, the planar array of UV-LEDs has a maximum width that does not exceed the outer diameter of the annular wall of the irradiation chamber.

[0052] The nature and advantages of the present invention will be more fully understood from the following drawings, detailed description, and claims.

[0053] The accompanying drawings illustrate embodiments of the present invention and, together with the general description of the invention given above and the detailed description given below, serve to explain the basic concepts of the invention. [Brief explanation of the drawings]

[0054] [Figure 1] 1 illustrates a fluid treatment device of the present invention. [Figure 2] 2 shows an exploded view of the components of the fluid treatment device of FIG. 1. [Figure 3] FIG. 1 is a front view of a fluid processing device. [Figure 4] 4 shows a cross-sectional view of the fluid treatment arrangement transverse to the longitudinal centerline taken along line 4-4 of FIG. 1. [Figure 5] 4 shows a cross-sectional view of the fluid treatment arrangement along the longitudinal centerline taken along line 4-4 of FIG. 1. [Figure 6] FIG. 4 is a cross-sectional view of FIG. 3 showing only a partial arrangement of the irradiation chamber, the planar array of UV-LEDs, the reflector panel and bracket, and the UV light emitter. [Figure 7] FIG. 1 is an exploded external view of an LED array module and its components. [Figure 8] 1 shows an exploded view of an LED array module and its components. [Figure 9] 9 shows a cross-sectional view of the heat exchanger taken along line 9-9 of FIG. 7. [Figure 10] 10 shows a cross-sectional view of the heat exchanger taken along line 10-10 of FIG. 7. [Figure 11] 1 illustrates an embodiment of a heat transfer system used in a fluid treatment device to cool a cooling plate of a heat exchange device. [Figure 12] 1 illustrates another embodiment of a heat transfer system. [Figure 13] 1 illustrates another embodiment of a heat transfer system. [Figure 14] 1 illustrates another embodiment of a heat transfer system. [Figure 15] 1 illustrates another embodiment of a heat transfer system. [Figure 16] Demonstrates the impact of LED position on performance for various array designs. DETAILED DESCRIPTION OF THE INVENTION

[0055] As used herein, the term "process flow (fluid)" refers to the fluid that is exposed to UV light.

[0056] As used herein, the term "heat-generating device" refers to any one, more, or all of the UV-LEDs, power supplies, electronic controls, and any other heat-generating devices associated with the UV-LED processing device and its operation.

[0057] The constraint of having to arrange a large array of UV-LEDs in a generally planar configuration creates unique design challenges, such as maintaining separation between the process flow and the UV-LED lamps, coupling the emitted UV light to the process flow, ensuring that the process flow is uniformly exposed to the emitted UV light (balancing fluence rate non-uniformities through induced mixing and maximizing optical coupling rather than creating a uniform fluence rate field), and ensuring that the level of UV flux within the chamber can be monitored.

[0058] The present invention provides a fluid treatment device designed to operate efficiently in accordance with the transmittance of the fluid flowing through the treatment chamber. For example, adding a UV transmittance sensor located beyond the flow cell from the UV-LEDs to the fluid treatment device can relay information to a software system to turn off one or more individual rows or columns of LEDs 44 in high-transmittance fluids and turn them back on if transmittance drops. Systems operating at a constant and unchanging UV output must provide a UV output that effectively treats fluids at the highest possible temperature and lowest possible transmittance, ensuring effective treatment of the entire fluid even under worst-case conditions. However, energy usage in the present system can be limited by varying the UV output based on temperature or transmittance, allowing the system to operate at a lower power output when temperatures are lower than the maximum and / or transmittance is higher than the minimum, thereby improving operational efficiency.

[0059] It should be appreciated that the present invention may also be used in conjunction with oxidizing chemicals such as chlorine, ozone, or hydrogen peroxide injected into the fluid to provide chemical and / or biological treatment.

[0060] 1-5 show a fluid processing apparatus 10 for treating a process flow with ultraviolet (UV) light.

[0061] <Housing> Apparatus 10 comprises a main cylindrical housing 11 having a cylindrical wall 12 having a longitudinal centerline 101, a pair of opposing flanged circular openings 14a and 14b at opposite ends of cylindrical wall 12, and a pair of rectangular flanged openings 13 at the top of two opposite ends of apparatus 10 mounted along the rectangular periphery of cylindrical wall 12. Cylindrical wall 12 also includes a pair of hoist rings 92 attached to the uppermost opposite ends of wall 12, a pair of UV sensor ports 15 at the lower two opposite ends of wall 12, and one or more drain holes at the bottom of wall 12 along a vertical plane through wall 12. In the illustrated embodiment, the UV sensor ports are located generally opposite the rectangular flanged openings 13 in cylindrical wall 12.

[0062] <Irradiation chamber> The cylindrical irradiation chamber 20 is constructed from an annular quartz wall that is transparent to UV light. The quartz wall 21 has an outer surface 22, an inner surface 23, and opposing first and second open ends 24a, 24b, providing a process flow path with a centerline 100. The thickness of the quartz wall is sufficient to withstand high pressures of the process flow, preferably up to about 1.0 MPa or greater. The inner diameter of the quartz wall can be about 6 inches (15 cm), 8 inches (20 cm), and 12 inches (30 cm), with a wall thickness of about 10 mm to about 20 mm and a length of up to 120 cm, e.g., 30 to 100 cm.

[0063] Coupling of light from the planar array can be enhanced by selecting an appropriate size (longitudinal length and lateral width) of the planar array 40 relative to the radii of curvature of the outer and inner diameters of the irradiation chamber 20. In some embodiments, the width of the planar array of UV-LEDs is equal to or less than the outer diameter of the annular wall of the irradiation chamber.

[0064] In some embodiments, the area of ​​the planar array of UV-LEDs is less than 60% of the area of ​​the exterior surface of the irradiation chamber, such as 50% or less, 40% or less, or 30% or less.

[0065] The quartz wall extends along the length of the opposing open ends of the quartz wall cylinder, is coaxially arranged with a pair of opposing circular openings 14a and 14b with flanges, is spaced by an elastomeric O-ring, and is sealed to the inlet coupling flange 18 and the outlet coupling flange 15 along its outer surface 23. The process flow supply pipe and the processed process flow discharge pipe are hermetically fixed in fluid communication to the inlet coupling flange 18 and the outlet coupling flange 15 respectively by a gasket or other well-known means, such as an elastomeric O-ring or a bolt fixture. The gasket material can be polytetrafluoroethylene (PTFE), fluorocarbon rubber material (FKM) which is a fluoroelastomer, or other suitable thermosetting elastomer or thermoplastic substance and a hybrid material of stainless steel. The fluorinated material is composed of carbon atoms surrounded by fluorine atoms and has excellent chemical resistance.

[0066] <Planar array of UV-LEDs> The fluid treatment device also includes a pair of LED array modules 60a, 60b, and each module can be removably attached to one of the pair of rectangular openings 13 with flanges. Each of the two LED array modules includes one or more conduit ports 79 for supplying power and electronic control wiring, and a pair of flow ports 64 for individual supply pipes and return pipes of the cooling flow.

[0067] As shown in FIGS. 7 and 8, each LED array module 60 includes a planar array of UV-LEDs for emitting ultraviolet light inside the cylindrical housing 11 and on the outer surface 23 of the quartz wall 21 of the irradiation chamber 20. The UV light emitted from each of the plurality of LEDs in the planar array hits the outer surface 23 of the quartz wall 21, and then, as shown in FIG. 6, passes through the quartz wall 21 and enters the process flow channel.

[0068] The planar array of UV LEDs has a length L2 along a centerline 102 parallel to the centerline 100 of the irradiation chamber 20, and a width W2 (see FIG. 7). The planar array of UV LEDs can include two or more smaller subarrays, which can be arranged to form an overall array pattern. Each planar array can include from a hundred or hundreds to a thousand or thousands of individual LEDs 44. In a preferred embodiment, the planar array 40 includes four UV LED subarrays, with each subarray including 1,000 to 1,500 individual LED lamps 44. Preferably, the normal to the planar array 40 passes through both the centerline 102 of the planar array 40 and the centerline 100 of the irradiation chamber 20. This arrangement provides that the rows of LEDs along the centerline 102 of the array emit UV light directed perpendicular (line 103, FIG. 4) to the centerline 100 of the irradiation chamber 20, and that this UV light strikes the outer surface 22 of the quartz wall 21 perpendicularly (at right angles).

[0069] Placing the planar array 40 of UV-LEDs around a limited portion of the irradiation chamber 20 allows for easy replacement of the planar UV emitters and simplifies manufacturing.

[0070] The placement of the LEDs is considered a key parameter for efficient coupling of the UV light source to the process flow, and the spacing between rows of LEDs 44 (known as the LED pitch) can be optimized. The LED pitch between the LED dies should preferably be 1 mm or greater.

[0071] In an exemplary case illustrating the relationship between the choice of LED location and its contribution to the overall irradiation chamber fluence, the importance of source location is evident (see Figure 16). Here, the relative contribution of each LED is plotted as a function of row position (distance from the LED die to the transparent irradiation chamber, along a tangent to its surface) for three array concepts. It can be seen that the greater the tangent displacement (i.e., the greater the displacement of the LED perpendicular to the radius of the irradiation chamber in the case of a planar array), the lower the relative contribution of that LED to the overall performance. It can also be seen that elements of the array design affect not only the slope of this decline with increasing displacement, but also the peak contribution from the centrally located LED in each design. This demonstrates the co-design techniques between the planar array and the irradiation chamber required to maximize efficiency and / or efficacy. Variations of UV-LED planar arrays can optionally include the design of reflective elements surrounding the periphery of the planar array. These reflective elements preferentially redirect the emitted UV radiation toward the process flow, as reflective brackets are specifically described herein. The planar array option shown in Figure 16 illustrates the impact of some of these features, such as the PTFE reflective bracket 32 ​​shown in Figure 4. The radiation of an LED moved tangentially farther (towards the lateral edge of the planar array 40) is reflected and reused in the process flow, as shown in Figure 6, whereas without the reflective element the radiation would be absorbed by other elements and wasted.

[0072] <Reflective cover> The outer, non-irradiated surfaces of the quartz wall 21, which are not directly exposed to the emitted UV light, can instead be surrounded, covered, or coated with a UV-reflective material, which reflects the UV light that passes through the quartz wall back into the process flow, more uniformly distributing the UV flux within the irradiation chamber and improving reactor performance. Non-limiting examples of UV-reflective materials include polytetrafluoroethylene (PTFE), aluminum, metallized thermoplastics, or other highly reflective materials, preferably with a bulk reflectivity of between 80% and 100% in the UV-C region emitted by the UV source.

[0073] One or more light reflectors are provided to cover a portion or portions of the outer surface 22 of the irradiation chamber 20. The portions that are irradiated with UV light directly emitted from the UV-LEDs are not covered by the light reflector. The light reflector covers only the remaining outer surface 22, preferably the entirety of it, and reflects refracted and diffused UV light that passes through the quartz wall 21 from the irradiation chamber back into the irradiation chamber 20. In the illustrated embodiment, the light reflector comprises one or more reflective panels disposed in contact with or on the non-irradiated portions of the outer surface. In some embodiments, the reflective panels are positioned at a certain spatial offset or distance from the outer surface 22 of the quartz wall 21.

[0074] The first reflector panel provides a guide or shield that limits the emitted UV light from striking certain areas of the outer surface of the quartz wall. In the illustrated embodiment, a pair of reflector brackets 32 a, 32 b are fixed within the cylindrical housing 11 along the upper and lower edges of the flanged opening 13 for each planar array 40. The blade portions 33 of each reflector bracket 32 ​​a, 32 b extend to tangentially engage the outer surface 22 of the quartz wall 21 ( FIGS. 4 and 6 ), thereby limiting UV light to the uncovered area consisting of an arc segment 25 along the length of the quartz wall 21 facing the planar array 40 of UV LEDs. During process flow operation, the reflective side surfaces of the reflector brackets 32 reflect light emitted at any angle from the UV LEDs, particularly light emitted at any angle from UV LEDs on the periphery of the planar array 40, toward the uncovered area.

[0075] In some embodiments, the planar array of UV-LEDs surrounds only a portion of the irradiation chamber 20 and directly irradiates UV light onto only a portion of the peripheral outer surface of the quartz wall 21. During treatment of the process flow, a portion of the UV light that enters the process flow path within the irradiation chamber 20 is diffused and / or refracted outward and passes through the quartz wall 21 via the inner surface 23 of the quartz wall 21. In the remaining area where the emitted UV light does not directly strike the quartz wall, another reflective panel 31 is disposed on the outer surface 22 of the quartz wall 21. In the illustrated embodiment, the reflective panel 31 covers the lower surface of the quartz wall, as shown in FIGS. 1 and 4 .

[0076] In some embodiments, the laterally opposed edges of adjacent reflective panels 31 and / or reflective brackets 32 are configured to overlap each other to prevent UV light from leaking therebetween.

[0077] In some embodiments, an opening 37 is provided in the reflective panel 31 to allow the UV light sensor 81 optical access to the outer surface of the quartz wall, as shown in Figure 4. The opening 37 allows the UV light sensor to be placed directly on the outer surface 22 of the quartz wall 21.

[0078] <LEDアレイモジュール> In some embodiments, the LED array module also includes and houses one or more other systems for providing power, control, and / or cooling to the planar array of UV LEDs. The planar array of LEDs 40 and these other systems in a single module allows for rapid replacement of worn or failed LEDs or power delivery components during operation or scheduled maintenance.

[0079] In the example shown in Figures 7 and 8, the LED array module 60 (in this case, the first module 60a) houses and interacts in stacked order a planar array of UV-LEDs 40, a heat exchanger 61, a control unit 75, a power supply unit 76 for supplying power to the planar array of UV-LEDs 40, a power bus 77, and a module cover 78.

[0080] A planar array of UV-LEDs (also referred to herein as a planar UV emitter) is typically an array of UV-emitting LEDs fixed to a printed circuit board (PCB) 41 and supported on a frame 42, which provides a planar heat sink to conduct heat away from the LEDs.

[0081] <Heat exchange equipment> The fluid treatment device includes a heat exchanger configured to remove heat generated by the planar UV-LED array. In some embodiments, the heat exchanger, or the second heat exchanger, is configured to remove heat generated by the planar UV emitter, and optionally, preferably, by one or more power supply and control units that power and control the operation of the planar array of UV-LEDs.

[0082] The heat exchange device 61 comprises a cooling plate having a first cooling surface and an opposite second cooling surface, where the planar heat sink of the planar array of UV-LEDs 40 is thermally coupled to the first planar cooling surface 65 of the cooling plate 62. A thermal adhesive 66 provides a thermally conductive interface between the planar heat sink and the first cooling surface 65. The thermal coupling is maintained by fastening the planar array 40 to the first cooling surface of the heat exchange device using removable fasteners, such as bolts.

[0083] In a preferred embodiment, the cooling plate is made of aluminum or other highly thermally conductive metal.

[0084] Cooling for the cooling plate 62 is provided by a plurality of elongated passages extending along the length of the cooling plate. In some embodiments, these passages consist of elongated tubes 68 arranged in a plurality of parallel slots 67 formed longitudinally in the first cooling surface 65, as shown in the cross-sectional view of the cooling plate in FIG. 9. A pair of opposing manifolds 63 are disposed at opposite ends of the cooling plate, each in sealed fluid communication with one end of the plurality of tubes 68 via a joint tube, as shown in the cross-sectional view of the cooling plate in FIG. 10. Cooled water is supplied to the opposing manifolds 63, and heated water is removed therefrom, via respective flow ports 64. The flow ports 64 are attached in fluid communication to a heat exchange system for supplying cooled water and removing heated water, as described elsewhere herein.

[0085] The elongated tubes are copper tubing, which is a more suitable material for contact with water than aluminum. In another embodiment, the elongated passages can be milled directly into the cooling plate.

[0086] The upper cooling surface of the cooling plate 62 is covered and in direct contact with the cooling cover 70. The planar array 40 and heat exchanger are secured to the inside of the frame 71 of the cooling cover 70 by fasteners such as bolts. The outer surface of the cooling cover 70 provides cooling to a power supply unit 76 and a control unit 75, which are secured directly to the cooling cover 70 by fasteners. A power bus 77 is electrically and physically connected to the power supply unit 76. Finally, a component cover 78 covers the control unit 75, power supply unit 76, and power bus 77 and is secured to the top surface of the cooling cover 70 by fasteners such as bolts. Electrical conduits 79 secured through the cover 78 provide access to the power and control modules.

[0087] In a preferred embodiment, the components on each side of the cooling plate 62 are individually serviceable and / or removable, reducing the amount of wear and tear during maintenance or refurbishment procedures.

[0088] The cooling plate is optimally used as both a structural element supporting the planar array of UV LEDs and as a power and control component. The most failure-prone components of the device 10 (UV LEDs and electronics) can be more easily replaced by simply disconnecting the power supply and controller and removing the LED array module 60. Furthermore, by connecting the power supply and electronic control components to the heat exchanger 61, their thermal load can be managed without the need for additional cooling elements. The electronics can be largely enclosed within the cover 78, improving protection and resistance to environmental hazards. Installation (mounting) is simplified because only power and control signals need to be routed to the LED array module 60. In conventional UV products, the power supply and control electronics are housed in separate, shielded enclosures. Placing all of the fragile components (electronics, UV LED array) in a single component (LED array module) simplifies manufacturing.

[0089] <Inflow rotation> To further improve the distribution of UV flux to the process flow within the irradiation chamber, the effect of the high UV intensity region immediately prior to the planar UV emitter can be minimized by imparting a swirling (vortex) motion to the process flow before it enters the quartz tube. This swirling motion is generated by static fluid mixing elements, such as vortex generators, positioned within the process flow upstream of the quartz tube.

[0090] One embodiment of a fluid mixing element is a bladed impeller connected to the inlet of the irradiation chamber to induce swirl in the flow. The shape and number of blades can be adjusted to induce the necessary swirl along the entire length of the irradiation chamber, allowing the fluid volume to achieve a uniform UV radiation dose. In other embodiments, the size and placement of the fluid mixing element can be selected depending on the processing flow rate and / or the inlet diameter of the irradiation chamber.

[0091] Because the cylindrical irradiation chamber has a constant cross-section, the chamber's configuration allows for the placement of flow control elements such as vortex generators. The vortex generators create a laminar swirling flow region that spirals the flow along the length of the irradiation chamber. In some embodiments, the vortex generators have 4 to 10 blades and, under nominal operating conditions, rotate the fluid at least one full rotation along the length of the irradiation chamber. This embodiment employs a discrete number of planar UV-LED arrays that do not cover the entire surface of the transmissive irradiation chamber, creating a highly non-uniform fluence rate field with "hot spots" adjacent to the array locations and "dark regions" elsewhere. Fluid dose is obtained by integrating the fluence between the high UV flux hot spots and the low UV flux dark regions. Optimizing the pitch of the vortex generators allows for tuning the laminar swirling flow to achieve a desired number of rotations along the length of the irradiation chamber, thereby evenly "integrating" the exposure between the hot spots and the dark regions. This design combines high optical efficiency through strong in-coupling and weak out-coupling with high hydraulic efficiency, resulting in overall high reaction efficiency, high operational efficiency, and low operational power consumption.

[0092] <UVセンサー> The present invention provides a method for measuring UVT using dual sensor locations and cycling output between the dual sensors, based on a known relationship between lamp output and sensors. Large-scale UV fluid treatment, whether for photochemical, sanitization, or disinfection purposes, requires very high UV light fluxes. Conventional mercury lamp systems typically use cylindrical lamps. These lamps can be installed directly in the process flow path and positioned to achieve uniform distribution of UV light within the flow path. This light distribution allows for predictable disinfection levels within the process flow.

[0093] In some embodiments, the percentage of light that the UV sensor can report can be reduced.

[0094] <Heat Transfer System> The present invention further provides a means for using a heat transfer system to balance process flow specifications / requirements with heat generation equipment specifications / requirements while optimizing cost / simplicity. Process flow specifications include temperature, chemical composition, suspended solids, etc. Heat generation specifications include thermal power output, etc. Heat transfer system requirements include steady state operating temperature and ease of maintenance, etc.

[0095] A heat transfer system can be integrated with the fluid treatment device 10 to provide a refrigeration flow to the heat exchange device 40. Typically, the volumetric flow rate of the refrigeration flow (3-20 gallons per minute, gpm) is very small compared to the process flow. The heat transfer system can include a refrigeration flow metering device to ensure that the refrigeration flow rate is sufficient for cooling but not excessive / wasted. In one embodiment, a metering valve can reduce the gauge pressure of the refrigeration flow in the cooling plate, making the refrigeration flow pressure lower than the process flow pressure.

[0096] The heat transfer systems described herein may include one or more temperature sensors for monitoring and / or controlling the temperature of the cooling flow.

[0097] In some embodiments, when a process flow is used as the cooling flow, the cooling flow is taken from the treated process flow downstream of fluid treatment device 10, and the cooling flow passing through the cooling plate of the heat exchange device is UV treated to reduce the occurrence of fouling in the cooling plate channels. In other embodiments, the cooling flow can be taken from the untreated process flow upstream of fluid treatment device 10. While the illustrated embodiment is for the cooling flow to be taken from either upstream or downstream of fluid treatment device 10, this applies to others as well.

[0098] In a first embodiment shown in FIG. 11 , a small pipe 98i is connected between a supply pipe 91 carrying the process flow and the inlet 64 of the heat exchanger 40. The outlet 64 of the heat exchanger 40 leads to a reservoir 99, which may be, for example, an underground well from which the process flow is originally sourced and pumped. The difference between the high pressure of the process flow in the supply pipe 91 and the low pressure in the reservoir 99 causes a flow of cooling water through the cooling plate 62 of the heat exchanger 61, cooling the cooling plate 62 and removing heat from the heat sinks of the UV-LEDs in the planar array 40 and, optionally, the power supply unit 76 and control electronics 75. This system requires minimal modifications to existing customer facilities.

[0099] For practical purposes, the reservoir 99 must be at a lower gauge pressure than the process flow to induce the refrigeration flow through the heat exchanger 61. The refrigeration flow must be discharged after passing through the cooling plate 61 and absorbing thermal energy. For fluid treatment devices 10 installed directly at the outlet of a public well, the optimal option is to direct the refrigeration flow at the outlet of the heat exchanger 61 back into the well. In this case, the well becomes the reservoir. In intermittent use scenarios, the refrigeration flow can simply be discharged into the ground or a small trench.

[0100] 12 is similar to the immediately preceding embodiment, except that a suitable feed reservoir is neither available nor necessary. A small portion of the process flow from downstream of fluid treatment device 10 passes through heat exchange device 40 and is then reinjected into the process flow stream at a point upstream of device 10. Because there is a small, and perhaps negligible, pressure difference between the feed and return refrigeration flows, pump 95 is used to create a pressure difference between the refrigeration flows at the inlet and outlet of heat exchange device 40.

[0101] Alternatively, a pressure differential can be created in the cooling flow by placing a Venturi or Pitot tube in the cooling flow inlet (process flow outlet) or in the scoop-shaped cooling flow inlet (process flow outlet) facing the process flow. The Pitot or Venturi tube effect creates a pressure differential large enough to draw a small but significant amount of process flow into the cooling flow inlet.

[0102] Some applications may restrict the process flow from directly contacting the cooling plate. For example, the cooling plate 61 may be aluminum, but regulations regarding water-contacting materials may prohibit the process flow from contacting the aluminum. Also, the chemistry of the process flow may corrode the cooling plate material. Solids in the process flow may pose a risk of clogging or damage to the cooling plate.

[0103] FIG. 13 illustrates a secondary closed-loop heat exchange subsystem that exchanges heat from the heat exchanger 61 with a separate secondary heat exchanger system 94. The cooling flow within the secondary heat exchanger system is circulated using a pump 95. The pump 95 circulates the cooling flow from the outlet port 64 of the heat exchanger 61 to the inlet 92i of the secondary heat exchanger system 94, where heat derived from the planar array of UV-LEDs 40 is removed. The cooling flow exits the outlet port 92o of the secondary heat exchanger system 94 and enters the inlet port 64 of the heat exchanger 61. These cooling systems can be fluids specifically designed to reduce freezing risk, reduce corrosion, etc., to avoid contact or mixing of the closed-loop cooling flow with the process flow, thereby providing greater design flexibility for the cooling plate 62. In some embodiments, the cooling flow liquid can include a mixture of glycol and water. The pump 95 can be driven by an electric motor, a water wheel or turbine powered by the process flow, a hydraulic drive, or a compressed air drive. Preferably, a pump is installed between the outlet of the heat exchanger 61 and the return of the cooling flow to the process flow to reduce the gauge pressure within the cooling plate.

[0104] 14, the secondary heat exchanger 94a can comprise a section of stainless steel tubing through which the process flow passes and a separate cooling flow tube wrapped around the exterior of supply piping 91 (e.g., copper tubing) through which the cooling flow passes. Heat from the cooling flow is transferred to the stainless steel tubing and then to the process flow. To increase the efficiency of the secondary heat exchanger 94a, the interior surface of the stainless steel tubing can be structured with conforming fins, grooves, or the like to increase the surface area in contact with the process flow.

[0105] In another embodiment shown in FIG. 15, the secondary heat exchanger 94b may be a section of stainless steel tubing having an inlet manifold in communication with the inlet ports 92i, an outlet manifold in communication with the outlet ports 92o, a plurality of exchange tubes in fluid communication between the inlet and outlet manifolds, and outer surfaces of the exchange tubes in fluid contact with the process flow.

[0106] While the present invention has been particularly described by way of a description of exemplary embodiments, the scope of the appended claims is not to be construed as being limited or restricted to such description. Additional advantages and modifications will readily occur to those skilled in the art. Accordingly, departures may be made from such description without departing from the scope of the invention.

Claims

1. 1. A fluid processing apparatus for processing a process flow, comprising: a) a cylindrical irradiation chamber constructed of a UV light transparent material, having an outer surface and with quartz walls forming a process flow channel; b) a planar array of UV light emitting diodes (LEDs) positioned to surround only a portion of the exterior of the quartz wall of the irradiation chamber and configured to emit UV light that passes through the quartz wall; c) a UV light reflector that covers the exterior of the quartz wall of the irradiation chamber that is not surrounded by the planar array of UV-LEDs and reflects UV light that passes through the quartz wall back into the process flow; and d) a heat transfer system configured to remove thermal energy from a heat-generating device comprising said planar array of UV-LEDs. A fluid treatment device comprising:

2. 10. The fluid treatment device of claim 1, wherein a maximum width of the planar array of UV-LEDs does not exceed an outer diameter of the annular wall of the irradiation chamber.

3. 1. A fluid processing apparatus for processing a process flow, comprising: a) a cylindrical irradiation chamber constructed of a UV light transmissive material and having an outer surface, an inner surface, first and second open ends forming a process flow path, and an annular wall having a centerline; b) a planar array of UV light emitting diodes (LEDs) configured to emit UV light, the planar array having a length and a width with a centerline parallel to a centerline of the irradiation chamber, wherein the emitted UV light impinges on and passes through an arc segment of the longitudinal exterior surface of the irradiation chamber, through the annular wall, and into a process flow path; c) a light reflector covering non-irradiated portions of the exterior surface of the irradiation chamber not within the arc segments to reflect UV light that has passed from the process flow path through the annular wall back through the annular wall; d) a heat exchanger configured to remove heat generated by the planar array of UV-LEDs. A fluid treatment device comprising:

4. 4. The fluid treatment device of claim 3, wherein the width of the planar array of LED-UV emitters is equal to or less than the outer diameter of the annular wall of the irradiation chamber.

5. 4. The fluid treatment device of claim 3, wherein the area of ​​the planar array of UV-LEDs is less than 60% of the area of ​​the exterior surface of the irradiation chamber.

6. 10. The fluid treatment device of claim 1, wherein a normal to the planar array passes through both a centerline of the planar array and a centerline of the irradiation chamber.

7. 10. The fluid treatment device of claim 9, further comprising an LED array module comprising the planar array of UV-LEDs, the heat exchange device, a power supply that provides power to the planar array of UV-LEDs, and a control board that controls operation of the UV-LEDs.

8. 10. The fluid treatment device of claim 1, wherein the irradiation chamber is enclosed within a secondary chamber including inlet and outlet openings for accessing the first and second open ends of the irradiation chamber, and a first flanged opening for mounting the LED array module.

9. 10. A fluid treatment device according to any preceding claim, further comprising a second planar array of UV-LEDs and a corresponding second heat exchange device.

10. 10. The fluid treatment device of claim 9, wherein the secondary chamber has a second flanged opening on an opposite side to the first flanged opening and is configured to orient the plane of the planar array of second UV-LEDs at an arc angle of 120 to 160 degrees relative to the plane of the planar array of first UV-LEDs.

11. 10. The fluid treatment device of claim 9, wherein the heat exchange device comprises a cooling plate having a first cooling surface and an opposite second cooling surface, wherein a planar array of heat sinks for the planar array of UV-LEDs is thermally connected to the first cooling surface and the power supply is thermally connected to the second cooling surface.

12. 10. A fluid treatment device according to any one of the preceding claims, further comprising means for rotating the untreated process flow at least one revolution over a discharge portion of the length of the irradiation chamber.

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