Photocatalytic air treatment

Abstract

A photocatalytic reactor is provided that includes a reaction chamber arranged to receive a gas stream containing one or more airborne pollutants. The reaction chamber includes a first interior surface, a second interior surface, a photocatalyst disposed on the first interior surface and the second interior surface for photocatalytic degradation of the one or more pollutants, and a light source arranged to illuminate at least a portion of the photocatalyst disposed on the first interior surface and the second interior surface. The first interior surface and the second interior surface have different parabolic arc-shaped profiles, and the profile of the first interior surface is a mirror image of the profile of the second interior surface. The first interior surface and the second interior surface can be continuous.

Description

Technical Field

[0001] The present invention relates to a photocatalytic reactor for treating airflow, and an air treatment apparatus including a photocatalytic reactor. Background Technology

[0002] Air handling equipment processes air to remove pollutants. Traditional air handling equipment uses only particulate filters, which physically capture airborne particles by size exclusion; high-efficiency particulate air (HEPA) filters remove at least 99.97% of 0.3μm particles. Some air handling equipment uses activated carbon filters to filter volatile chemicals from the air. When used for air purification, activated carbon filters out pollutants by adsorption, and therefore has only a limited capacity, so activated carbon filters eventually need to be replaced to maintain their filtration performance. In addition to capturing pollutants, certain air pollutants (PCOs) can be destroyed using technologies such as photocatalytic oxidation. Photocatalytic oxidation can be used to oxidize harmful air pollutants into less harmful compounds, such as oxidizing volatile organic compounds (VOCs) into carbon dioxide and water. This reaction is catalyzed by a catalytic surface activated by absorbing photons. Moisture and oxygen in the air provide the necessary hydrogen and oxygen atoms for the reaction to proceed, so no reactive chemicals other than pollutants are consumed. Summary of the Invention

[0003] According to a first aspect of the invention, a photocatalytic reactor is provided, comprising a reaction chamber arranged to receive a gas stream containing one or more airborne pollutants. The reaction chamber includes a first inner surface, a second inner surface, a photocatalyst disposed on the first and second inner surfaces for photocatalytic degradation of one or more pollutants, and a light source arranged to irradiate at least a portion of the photocatalyst disposed on the first and second inner surfaces. The first and second inner surfaces have different parabolic profiles, and the profile of the first inner surface is a mirror image of the profile of the second inner surface. The first and second inner surfaces may be continuous.

[0004] The light source may include a light-emitting diode (LED). A first inner surface and a second inner surface may be arranged symmetrically about the optical axis of the LED. The first and second inner surfaces may be arranged such that at least a portion of the first inner surface is illuminated by a first half of the LED, and at least a portion of the second inner surface is arranged to be illuminated by a second half of the LED.

[0005] The light source may include a plurality of light-emitting diodes (LEDs), each LED being arranged to illuminate at least a portion of a first inner surface and a second inner surface, the first and second inner surfaces being arranged symmetrically about the optical axis of each of the plurality of LEDs. The plurality of LEDs may be distributed such that each LED illuminates a different portion of the first and second inner surfaces. The reaction chamber may be longitudinal, and the plurality of LEDs are longitudinally aligned.

[0006] The reaction chamber may include an air inlet and an air outlet, and is arranged such that the airflow passing between the air inlet and the air outlet contacts the photocatalyst.

[0007] The reaction chamber may include at least one layer of transparent material that separates the photocatalyst from the light source.

[0008] The first inner surface and the second inner surface can be separated from the outermost surface of at least one layer of transparent material by a maximum distance of no more than 10 mm, preferably no more than 7 mm, and more preferably from 1 mm to 7 mm.

[0009] The photocatalytic reactor may include multiple reaction chambers. These chambers may be distributed around a common axis, each chamber arranged such that a first inner surface and a second inner surface face inwards, and a light source is centrally located relative to the first and second inner surfaces. The chambers may be arranged sequentially. The chambers may be arranged such that this arrangement has rotational symmetry about the common axis, and preferably has n-fold rotational symmetry, where n equals the number of reaction chambers.

[0010] According to a second aspect of the invention, an air treatment apparatus comprising a photocatalytic reactor according to the first aspect is provided. Attached Figure Description

[0011] The present invention will be described by way of example only with reference to the following figures, wherein:

[0012] Figure 1A This is a perspective view of an example photocatalytic reactor used in air treatment equipment;

[0013] Figure 1B yes Figure 1A An end view of the photocatalytic reactor;

[0014] Figure 2A This is a perspective view of an example of a photocatalytic reactor used in air treatment equipment;

[0015] Figure 2B yes Figure 2A An end view of the photocatalytic reactor;

[0016] Figure 3A This is a perspective view of an example of a photocatalytic reactor used in air treatment equipment;

[0017] Figure 3B yes Figure 3A An end view of the photocatalytic reactor;

[0018] Figure 4 This is an end view of an example of a photocatalytic reactor used in air treatment equipment;

[0019] Figure 5A This is a perspective view of another example of a photocatalytic reactor used in air treatment equipment;

[0020] and

[0021] Figure 5B yes Figure 5A An end view of the photocatalytic reactor. Detailed Implementation

[0022] Now refer to Figure 1A and 1B This description of an improved photocatalytic reactor is by way of example only. The photocatalytic reactor is generally indicated by reference numeral 1000. The photocatalytic reactor 1000 includes a reaction chamber 1001 and a photocatalyst 1004. The reaction chamber 1001 is arranged to receive an airflow containing one or more airborne pollutants. The photocatalyst 1004 is used for the photocatalytic degradation of one or more pollutants and is disposed on a substrate 1003 provided by the reaction chamber 1001. The photocatalytic reactor 1000 also includes a light-emitting diode printed circuit board (“LED PCB”) 1012, which includes a printed circuit board 1008 to which a plurality of light-emitting diodes 1009 are mounted on a first side 1006 of the printed circuit board 1008. The photocatalytic reactor 1000 is arranged such that the substrate 1003 is irradiated by the light-emitting diodes 1009 to promote photocatalytic degradation. Specifically, the substrate 1003 is arranged to shield the LED PCB 1012 such that light emitted from the light-emitting diodes 1009 of the LED PCB 1012 irradiates the substrate 1003.

[0023] exist Figure 1A and 1BIn the example shown, the photocatalytic reactor 1000 includes an elongated reaction chamber 1001 surrounding an elongated LED PCB 1012, which extends along the length of the reaction chamber 1001. The reaction chamber 1001 includes a reaction chamber inlet (not shown) at a first end and a reaction chamber outlet (not shown) at a second end, such that an airflow passing between the reaction chamber inlet and outlet contacts a photocatalyst 1004 disposed on a substrate 1003. Partitions / barriers 1005A and 1005B thus separate the photocatalyst 1004 reaction chamber from the LED PCB 1012, at least a portion of which is transparent to radiation emitted by a light-emitting diode 1009, allowing the photocatalyst 1004 to be irradiated by the light-emitting diode 1009. Then, the multiple light-emitting diodes 1009 of the LED PCB 1012 are spaced apart and longitudinally aligned along the first side 1006 of the length of the LED PCB 1012, thereby providing a light source along the entire length of the photocatalytic reactor 1000.

[0024] exist Figure 1A and 1B In the example shown, the substrate 1003 of the reaction chamber 1001 includes a plurality of protrusions provided by fins 1011A, 1011B, each protrusion extending inward away from the inner surface of the reaction chamber 1001, and a photocatalyst 1004 disposed on at least one surface of each fin 1011A, 1011B. These fins 1011A, 1011B provide a high surface area for the photocatalytic degradation of pollutants. Each fin 1011A, 1011B is elongated, having a length (L) along the length of the elongated reaction chamber 1001, and a height (H) defined by how far the fins 1011A, 1011B extend inward away from the corresponding inner surface of the reaction chamber 1001. Therefore, the fins 1011A, 1011B are longitudinal, and the longitudinal axis of each fin 1011A, 1011B is perpendicular to the optical axis of the light-emitting diode 1009. Therefore, fins 1011A and 1011B define a channel 1002 between them, which extends along the length of the reaction chamber 1001 for air to flow from the air inlet to the air outlet. In the example shown, each fin 1011A and 1011B has a partially curved cross-section (i.e., fin profile) along its height. However, in an alternative arrangement, each fin 1011A and 1011B may have a straight cross-section.

[0025] Fins 1011A and 1011B include a first set of fins 1011A and a second set of fins 1011B, with a photocatalyst 1004 disposed on each fin. The first set of fins 1011A and the second set of fins 1011B are arranged such that light from a light-emitting diode 1009 illuminates at least a portion of the length of the face 1013 of each fin 1011A and 1011B along the entire height of the face 1013. In other words, each light-emitting diode 1009 illuminates at least one face 1013 of each fin 1011A and 1011B without being blocked by any adjacent fins, although multiple light-emitting diodes 1009 may be required to illuminate the entire length of the fins 1011A and 1011B (e.g., multiple light-emitting diodes arranged longitudinally). The light-emitting diodes 1009 are distributed to different but potentially overlapping portions that illuminate at least one face 1013 of each fin 1011A and 1011B.

[0026] exist Figure 1A and 1B In the example shown, each of the first set of fins 1011A is arranged such that a line extending from the base 1015 of fin 1011A through the tip 1016 of fin (e.g., extending along the height of the fin, similar to a chord) points to a first convergence point or intersection (F1). Then, each of the second set of fins 1011B is arranged such that a line extending from the base 1015 of fin 1011B through the tip 1016 of fin 1011B points to a second convergence point (F2). The first convergence point (F1) is different from the second convergence point (F2), and both the first convergence point (F1) and the second convergence point (F2) are offset relative to the position of the light-emitting diode 1009.

[0027] A first set of fins 1011A extends inward from a first inner surface 1018A of the reaction chamber 1001, and a second set of fins 1011B extends inward from a second inner surface 1018B of the reaction chamber 1001. The first inner surface 1018A and the second inner surface 1018B generally face the light-emitting diode 1009. The first inner surface 1018A and the second inner surface 1018B are arranged symmetrically around the optical axis (O) of the light-emitting diode, such that the first set of fins 1011A is arranged to be illuminated by a first half of each light-emitting diode 1009, and the second set of fins 1011B is arranged to be illuminated by a second half of each light-emitting diode 1009. Figure 1A and 1B In the example shown, the photocatalyst 1004 is also disposed on the first inner surface 1018A and the second inner surface 1018B of the reaction chamber 1001.

[0028] The first inner surface 1018A and the second inner surface 1018B have different arcuate profiles (i.e., their cross-sections are curve segments with different focal points), and the profile of the first inner surface 1018A is a mirror image of the profile of the second inner surface 1018B. In other words, the first inner surface 1018A and the second inner surface 1018B are reflections of each other, making them together mirror / reflection symmetry. The first inner surface 1018A and the second inner surface 1018B can each have either a circular arcuate profile or a parabolic arcuate profile.

[0029] exist Figure 1A and 1B In the example shown, the partitions 1005A and 1005B comprise two layers of transparent material disposed between and separating the light-emitting diode 1009 and the photocatalyst 1004. These two layers of transparent material include a first transparent material 1005A, which is separated from the second transparent material 1005B by a gap. These transparent material layers 1005A and 1005B are airtight and transparent to the radiation emitted by the light-emitting diode 1009. Figure 1A and 1B In the example shown, two layers of transparent materials 1005A and 1005B are tubular and concentrically arranged around the LED PCB 1012. The innermost part of these tubes provides a conduit, in which the LED PCB 1012 is located, and the conduit is arranged to allow airflow through the conduit to cool the light-emitting diode 1009.

[0030] Providing a double-layer partition between the light-emitting diode 1009 and the photocatalyst 1004 reduces heat loss between the first portion 1019 and the second portion 1020 of the reaction chamber 1001, where the first portion 1019 is arranged to receive an airflow containing contaminants and the second portion 1020 contains the LED PCB 1012, thereby improving energy efficiency. This reduction in heat loss is particularly beneficial when active cooling of the light-emitting diode 1009 is implemented.

[0031] Figure 2A and 2B Another example of an improved photocatalytic reactor is shown. Photocatalytic reactors are generally designated by reference numeral 2000. The photocatalytic reactor 2000 includes a reaction chamber 2001 and a photocatalyst 2004. The reaction chamber 2001 is arranged to receive a gas stream containing one or more airborne pollutants. The photocatalyst 2004 is used for the photocatalytic degradation of one or more pollutants and is disposed on a substrate 2003 provided by the reaction chamber 1001. The photocatalytic reactor 2000 is very similar to the one referenced above. Figure 1A and 1BThe photocatalytic reactor described herein is thus indicated by corresponding reference numerals for similar or corresponding parts or features in these embodiments. Specifically, the photocatalytic reactor 2000 includes an elongated reaction chamber 2001 surrounding an elongated LED PCB 2012, the LED PCB 2012 extending along the length of the reaction chamber 2001. The reaction chamber 2001 includes a reaction chamber inlet (not shown) at a first end and a reaction chamber outlet (not shown) at a second end, such that an airflow passing between the reaction chamber inlet and the reaction chamber outlet contacts a photocatalyst 2004 disposed on a substrate 2003. A partition / barrier 2005 then separates the reaction chamber 2001 from the LED PCB 2012, at least a portion of which is transparent to radiation emitted by light-emitting diodes 2009 and 2010, allowing the photocatalyst 2004 to be irradiated by the light-emitting diodes 2009 and 2010.

[0032] exist Figure 2A and 2B In the example shown, the LED PCB 2012 is double-sided. Therefore, the LED PCB 2012 includes a printed circuit board 2008, wherein a plurality of first light-emitting diodes 2009 are mounted to a first side 2006 of the printed circuit board, and a plurality of second light-emitting diodes 2010 are mounted to a second side 2007 of the printed circuit board. Thus, the LED PCB 2012 includes either a double-sided circuit board or a multilayer circuit board. The first light-emitting diodes 2009 of the LED PCB 2012 are spaced apart and longitudinally aligned along the first side 2006 of the length of the LED PCB 2012, and the second light-emitting diodes 2010 are spaced apart and longitudinally aligned along the second side 2007 of the length of the LED PCB 2012, thereby providing a light source along the entire length of the photocatalytic reactor 2000.

[0033] The photocatalytic reactor 2000 is thus arranged such that the substrate 2003 is irradiated by a first light-emitting diode 2009 and a second light-emitting diode 2010 to promote photocatalytic degradation. Specifically, the substrate 2003 is arranged to shield the LED PCB 2012 such that light emitted from the light-emitting diodes 2009 and 2010 of the LED PCB 2012 irradiates the substrate 2003. For this purpose, the substrate 2003 is arranged to surround the LED PCB 2012.

[0034] exist Figure 2A and 2BIn the example shown, the reaction chamber 2001 of the photocatalytic reactor 2000 is also double-sided. Therefore, the reaction chamber 2001 includes a first side 2001A and a second side 2001B, wherein the first side 2001A is arranged to be illuminated by a first light-emitting diode 2009 disposed on a first side 2006 of a printed circuit board 2008, and the second side 2001B is arranged to be illuminated by a second light-emitting diode 2010 disposed on a second side 2007 of a printed circuit board 2008.

[0035] The dual-sided photocatalytic reactor configuration reduces the length of the reactor without compromising the overall volume, which is especially important when integrating photocatalytic reactors into home air treatment equipment, and also reduces material costs, particularly those associated with the partitions 2005A, 2005B and the printed circuit board 2008.

[0036] Then, the first side 2001A and the second side 2001B of the reaction chamber 2001 are replicated respectively. Figure 1A and 1B The reaction chamber 1001 shown has a finned arrangement. Specifically, the first side 2001A of the reaction chamber 2001 includes a first set of fins 2011A and a second set of fins 2011B, and the second side 2001B of the reaction chamber 2001 includes a third set of fins 2011C and a fourth set of fins 2011D. A photocatalyst 2004 is disposed on at least one face 2013 of each fin 2011. The first set of fins 2011A and the second set of fins 2001B are arranged such that light from a first light-emitting diode 2009 illuminates at least a portion of the length of the face 2013 of each fin 2011A, 2011B along the entire height of the face 2013. Then, the third set of fins 2011C and the fourth set of fins 2011D are arranged such that light from a second light-emitting diode 2010 illuminates at least a portion of the length of the face 2013 of each fin 2011C, 2011D along the entire height of the face 2013.

[0037] On the first side 2001A of the reaction chamber 2001, each of the first set of fins 2011A is arranged such that a line extending from the base 2015 of the fin 2011A through the tip 2016 of the fin (e.g., extending along the height of the fin, similar to a chord) points to a first convergence point or intersection (F1). Then, each of the second set of fins 2011B is arranged such that a line extending from the base 2015 of the fin 2011B through the tip 2016 of the fin 2011B points to a second convergence point (F2). The first convergence point (F1) is different from the second convergence point (F2), and both the first convergence point (F1) and the second convergence point (F2) are offset relative to the position of the first light-emitting diode 2009.

[0038] Accordingly, on the second side 2001B of the reaction chamber 2001, each of the third set of fins 2011C is arranged such that a line extending from the base 2015 of fin 2011C through the tip 2016 of fin 2011C points to a third convergence point or intersection (F3). Then, each of the fourth set of fins 2011D is arranged such that a line extending from the base 2015 of fin 2011D through the tip 2016 of fin 2011D points to a fourth convergence point (F4). The third convergence point (F3) is different from the fourth convergence point (F4), and both the third convergence point (F3) and the fourth convergence point (F4) are offset relative to the position of the second light-emitting diode 2010.

[0039] The first set of fins 2011A extends inward from the first inner surface 2018A on the first side 2001A of the reaction chamber 2001. The second set of fins 2011B extends inward from the second inner surface 2018B on the first side 2001B of the reaction chamber 2001. The first inner surface 2018A and the second inner surface 2018B generally face the first light-emitting diode 2009. The third set of fins 2011C extends inward from the third inner surface 2018C on the second side 2001B of the reaction chamber 2001. The fourth set of fins 2011D extends inward from the fourth inner surface 2018D on the second side 2001B of the reaction chamber 2001. The third inner surface 2018C and the fourth inner surface 2018D generally face the second light-emitting diode 2010.

[0040] from Figure 2A and 2B As can be seen, the LED PCB 2012 is centrally located within the volume defined by the substrate 2003. The separator 2005 thus comprises a single layer of transparent material disposed between and separating the light-emitting diodes 2009 and 2010 and the photocatalyst 2004. This transparent material layer is airtight and transparent to the radiation emitted by the light-emitting diodes 2009 and 2010. Figure 2A and 2B In the example shown, the single-layer transparent material 2005 is tubular and concentrically arranged around the LED PCB 3012. The transparent material tube 2005 provides a conduit within which the LED PCB 1012 is located, and the conduit is arranged to allow airflow through it to cool the light-emitting diodes 2009 and 2010.

[0041] Those skilled in the art will recognize that it is possible to Figure 1A , 1B The key features of the photocatalytic reactors 1A and 1B are combined. Therefore, reference will now be made to... Figure 3A and 3BAnother example of an improved photocatalytic reactor is described. A photocatalytic reactor is generally designated by reference numeral 3000. The photocatalytic reactor 3000 includes a reaction chamber 3001 and a photocatalyst 3004. The reaction chamber 3001 is arranged to receive a gas stream containing one or more gaseous pollutants. The photocatalyst 3004 is used for the photocatalytic degradation of one or more pollutants and is disposed on a substrate 3003 provided by the reaction chamber 1001. The photocatalytic reactor 3000 is very similar to the one described above. Figure 2A and 2B The photocatalytic reactor described herein is thus indicated by corresponding reference numerals for similar or corresponding parts or features in these embodiments. Specifically, the photocatalytic reactor 3000 includes an elongated reaction chamber 3001 surrounding an elongated LED PCB 3012, the LED PCB 3012 extending along the length of the reaction chamber 3001. The reaction chamber 3001 includes a reaction chamber inlet (not shown) at a first end and a reaction chamber outlet (not shown) at a second end, such that an airflow passing between the reaction chamber inlet and the reaction chamber outlet contacts a photocatalyst 3004 disposed on a substrate 3003. Partitions / barriers 3005A, 3005B thus separate the reaction chamber 3001 from the LED PCB 3012, at least a portion of which is transparent to radiation emitted by light-emitting diodes 3009, 3010, allowing the photocatalyst 3004 to be irradiated by the light-emitting diodes 3009, 3010.

[0042] exist Figure 3A and 3B In the example shown, both the LED PCB 3012 and the reaction chamber 3001 are double-sided. However, compared to... Figure 2A and 2B The example shown differs; the separators 3005A and 3005B separating the photocatalyst 304 from the LED PCB 3012 comprise two layers of transparent material. These two layers include a first transparent material 3005A, which is separated from the second transparent material 3005B by a gap. These transparent material layers 3005A and 3005B are airtight and transparent to the radiation emitted by the light-emitting diodes 3009 and 3010. Figure 3A and 3B In the example shown, two layers of transparent materials 3005A and 3005B are tubular and concentrically arranged around the LED PCB 3012. The innermost part of these tubes provides a conduit, in which the LED PCB 3012 is located, and the conduit is arranged to allow airflow through the conduit to cool the light-emitting diodes 3009 and 3010.

[0043] Now refer to Figure 4Another example illustrating an improved photocatalytic reactor. Photocatalytic reactors are typically designated by reference numeral 4000, and in... Figure 4 The cross-section is shown. The photocatalytic reactor 4000 includes three reaction chambers 4001, 4101, 4201 and a photocatalyst 4004. Each reaction chamber is arranged to receive an airflow containing one or more airborne pollutants. The photocatalyst 4004 is used for photocatalytic degradation of one or more pollutants and is disposed on a substrate 4003 provided by each reaction chamber 4001, 4101, 4201. The photocatalytic reactor 4000 also includes light-emitting diode printed circuit boards (“LED PCBs”) 4012, 4112, 4212 within each reaction chamber 4012, 4112, 4212. Each LED PCB 4012, 4112, 4212 includes a printed circuit board 4008, with a plurality of light-emitting diodes 4009 mounted to a first side of the printed circuit board 4008. The photocatalytic reactor 4000 is arranged such that the substrate 4003 provided by each reaction chamber 4001, 4101, 4201 is irradiated by the light-emitting diodes 4009 of the corresponding LED PCBs 4012, 4112, 4212 to promote photocatalytic degradation. Specifically, the substrate 4003 provided by each reaction chamber 4012, 4112, 4212 is arranged to shield the corresponding LED PCBs 4012, 4112, 4212, such that light emitted from the light-emitting diodes 4009 of the LED PCBs 4012, 4112, 4212 irradiates the substrate 4003.

[0044] exist Figure 4 In the example shown, each reaction chamber 4001, 4101, 4201 is elongated and surrounds a correspondingly elongated LED PCB 4012, 4112, 4212 extending along the length of the reaction chambers 4001, 4101, 4201. Each reaction chamber 4001, 4101, 4201 includes a reaction chamber inlet (not shown) at a first end of the reaction chamber and a reaction chamber outlet (not shown) at a second end of the reaction chamber, such that airflow passing between the reaction chamber inlet and the reaction chamber outlet contacts a photocatalyst 4004 disposed on a substrate 4003. A partition / barrier 4005 then separates the photocatalyst 4004 from each LED PCB 4012, 4112, 4212, at least a portion of which is transparent to radiation emitted by the light-emitting diode 4009, allowing the photocatalyst 4004 to be irradiated by the light-emitting diode 4009. The plurality of light-emitting diodes 4009 in each LED PCB 4012, 4112, 4212 are then spaced apart and longitudinally aligned along the first side of the length of the printed circuit board 4008, thereby providing a light source along the entire length of the respective reaction chambers 4001, 4101, 4201.

[0045] exist Figure 4 In the example shown, the substrate 4003 of each reaction chamber 4001, 4101, 4201 includes a plurality of protrusions provided by fins 4011A, 4011B, each protrusion extending inward away from the inner surface of the reaction chambers 4001A, 4001B, 4001C, and a photocatalyst 4004 is disposed on at least one surface of each fin 4011A, 4011B. These fins 4011A, 4011B provide a high surface area for the photocatalytic degradation of pollutants. Each fin 4011A, 4011B is elongated, having a length along the length of the elongated reaction chambers 4001A, 4001B, 4001C, and a height defined by how far the fins 4011A, 4011B extend inward away from the respective inner surface of the reaction chambers 4001, 4101, 4201. Therefore, fins 4011A and 4011B are longitudinal, with the longitudinal axis of each fin 4011A and 4011B perpendicular to the optical axis of the light-emitting diode 4009. Fins 4011A and 4011B thus define a channel 4002 between them, extending along the length of the respective reaction chambers 4001, 4101, and 4201 for air flow from the air inlet to the air outlet. In the example shown, each fin 4011A and 4011B has a straight cross-section (i.e., fin profile) along its height. However, in an alternative arrangement, each fin 4011A and 4011B may have a curved cross-section.

[0046] Each reaction chamber 4001, 4101, 4201 contains fins 4011A, 4011B, including a first set of fins 4011A and a second set of fins 4011B, with a photocatalyst 1004 disposed on each fin. The first set of fins 4011A and the second set of fins 4011B are arranged such that light from the corresponding light-emitting diode 4009 illuminates at least a portion of the length of the surface 4013 of each fin 4011A, 4011B along the entire height of the surface 4013. In other words, within reaction chambers 4001, 4101, 4201, each light-emitting diode 4009 illuminates at least one surface 4013 of each fin 4011A, 4011B along the entire height without being obstructed by adjacent fins, although multiple light-emitting diodes 4009 may be required to illuminate the entire length of the fins 4011A, 4011B (e.g., multiple light-emitting diodes arranged longitudinally). In each reaction chamber 4001, 4101, 4201, light-emitting diodes 4009 are distributed in different but possibly overlapping portions of at least one face 4013 that illuminates each fin 4011A, 4011B.

[0047] exist Figure 4In the example shown, within each reaction chamber 4001, 4101, 4201, each of the first set of fins 4011A is arranged such that a line extending from the base 4015 of fin 4011A through the tip 4016 of fin (e.g., extending along the height of the fin, similar to a chord) points to a first convergence point or intersection (F1). Then, each of the second set of fins 4011B is arranged such that a line extending from the base 4015 of fin 4011B through the tip 4016 of fin 4011B points to a second convergence point (F2). The first convergence point (F1) is different from the second convergence point (F2), and both the first convergence point (F1) and the second convergence point (F2) are offset relative to the position of the light-emitting diode 4009.

[0048] A first set of fins 4011A extends inward from the first inner surface 4018A of the corresponding reaction chambers 4001, 4101, and 4201, and a second set of fins 4011B extends inward from the second inner surface 4018B of the corresponding reaction chambers 4001, 4101, and 4201. The first inner surface 4018A and the second inner surface 4018B generally face the light-emitting diode 4009. The first inner surface 4018A and the second inner surface 4018B are arranged symmetrically around the optical axis of the light-emitting diode, such that the first set of fins 4011A is arranged to be illuminated by the first half of each light-emitting diode 4009, and the second set of fins 4011B is arranged to be illuminated by the second half of each light-emitting diode 4009. Figure 4 In the example shown, the photocatalyst 4004 is also disposed on the first inner surface 4018A and the second inner surface 4018B of each reaction chamber 4001, 4101, 4201.

[0049] Within each reaction chamber 4001, 4101, and 4201, the first inner surface 4018A and the second inner surface 4018B have different arcuate profiles (i.e., their cross-sections are curve segments with different focal points), and the profile of the first inner surface 4018A is a mirror image of the profile of the second inner surface 4018B. In other words, the first inner surface 4018A and the second inner surface 4018B are reflections of each other, thus possessing mirror / reflection symmetry together. The first inner surface 4018A and the second inner surface 4018B can each have either a circular arcuate profile or a parabolic arcuate profile.

[0050] from Figure 4As can be seen, reaction chambers 4001, 4101, and 4201 are distributed around a common axis. Specifically, the three reaction chambers 4001, 4101, and 4201 are arranged such that this arrangement has triple rotational symmetry about the common axis. The three reaction chambers 4001, 4101, and 4201 are also arranged continuously, such that the substrate 4003 of the reaction chambers 4001, 4101, and 4201 defines the volume of the space where LED PCBs 4012, 4112, and 4212 are located. The partition 4005 thus includes a single layer of transparent material disposed between and separating the LED PCBs 4012, 4112, and 4212 and the photocatalyst 4004. This transparent material layer is airtight and transparent to the radiation emitted by the light-emitting diode 4009. Figure 4 In the example shown, a single layer of transparent material 4005 is in the form of a leaf-shaped tube and is concentrically arranged around LED PCBs 4012, 4112, and 4212. The leaf-shaped tube 4005 of the transparent material provides a conduit within which LED PCBs 4012, 4112, and 4212 are located, and the conduit is arranged to allow airflow through the conduit to cool the light-emitting diodes 4009.

[0051] The photocatalytic reactor 4000 described above includes three reaction chambers. Those skilled in the art will recognize that the photocatalytic reactor 4000 can include any number of reaction chambers. The photocatalytic reactor 4000 described above is elongated. Those skilled in the art will appreciate that this is not necessarily the case.

[0052] Figure 1A , 1B Photocatalytic reactors 2A, 2B, 3A, 3B, and 4 all include fins arranged to maximize the irradiated surface area, thereby maximizing the efficiency of the photocatalytic reactor. In doing so, this arrangement also minimizes the number of light-emitting diodes required to irradiate the fins, as no shading optimizes the surface area irradiated by each light-emitting diode.

[0053] Figure 1A , 1B Photocatalytic reactors 2A, 2B, 3A, 3B, and 4 all include fins that provide a relatively high surface area for the photocatalyst. Reference will now be made to... Figure 5A and 5B The description includes an example of an improved photocatalytic reactor that does not include such fins. Photocatalytic reactors are generally designated by reference numeral 5000. Photocatalytic reactor 5000 includes two reaction chambers 5001, 5101 and a photocatalyst 5004, each reaction chamber arranged to receive a gas stream containing one or more airborne pollutants. The photocatalyst 5004 is used for the photocatalytic degradation of one or more pollutants and is disposed on substrates 5003, 5103 provided by each reaction chamber 5001, 5101. Figure 5A and 5B In the example shown, the photocatalytic reactor 5000 also includes a double-sided light-emitting diode printed circuit board (“LED PCB”) 5012. Therefore, the LED PCB 5012 includes a printed circuit board 5008, a plurality of first light-emitting diodes 5009 mounted to a first side 5006 of the printed circuit board 5008, and a plurality of second light-emitting diodes 5010 mounted to a second side 5007 of the printed circuit board 5008. Thus, the LED PCB 5012 includes either a double-sided circuit board or a multilayer circuit board.

[0054] The photocatalytic reactor 5000 is thus arranged such that the substrate 5003 of the first reaction chamber 5001 is illuminated by a first light-emitting diode 5009 mounted on a first side 5006 of a printed circuit board 5008, while the substrate 5103 of the second reaction chamber 5101 is illuminated by a second light-emitting diode 5010 mounted on a second side 5007 of the printed circuit board 5008. Specifically, the substrate 5003 of the first reaction chamber 5001 is arranged to shield the LED PCB 5012, such that light emitted from the first light-emitting diode 5009 illuminates the substrate 5003, and the substrate 5103 of the second reaction chamber 5101 is arranged to shield the LED PCB 5012, such that light emitted from the second light-emitting diode 5010 illuminates the substrate 5103.

[0055] exist Figure 5A and 5B In the example shown, the photocatalytic reactor 5000 is elongated, and the first and second reaction chambers 5001 and 5101 are distributed around the axis of the photocatalytic reactor 5000, such that the arrangement has double rotational symmetry about the axis. The reaction chambers 5001 and 5101 are also arranged continuously, such that the substrates 5003 and 5103 of the reaction chambers 5001 and 5101 define the volume of the space in which the LED PCB 5012 is located. In particular, the LED PCB 5012 is elongated, axially aligned within the elongated photocatalytic reactor 5000, and extends along the length of the reaction chambers 5001 and 5101. The first light-emitting diodes 5009 of the LED PCB 5012 are spaced apart and longitudinally aligned along a first side 5006 of the length of the LED PCB 5012, and the second light-emitting diodes 5010 are spaced apart and longitudinally aligned along a second side 5007 of the length of the LED PCB 5012, thereby providing a light source along the entire length of the photocatalytic reactor 5000.

[0056] Reaction chambers 5001 and 5101 each include a reaction chamber inlet (not shown) at a first end of the reaction chambers 5001 and 5101 and a reaction chamber outlet (not shown) at a second end of the reaction chambers 5001 and 5101, such that airflow passing between the reaction chamber inlet and the reaction chamber outlet contacts the photocatalyst 5004 disposed on the respective substrates 5003 and 5103. A partition / barrier 5005 then separates the reaction chambers 5001 and 5101 from the LED PCB 5012. At least a portion of the partition 5005 is transparent to radiation emitted by the light-emitting diodes 5009 and 5010, allowing the photocatalyst 5004 to be irradiated by the light-emitting diodes 5009 and 5010. Figure 5A and 5B In the example shown, the partition 5005 comprises a single layer of transparent material that is tubular and concentrically arranged around the LED PCB 5012. This transparent material tube provides a conduit within which the LED PCB 5012 is located, and the conduit is arranged to allow airflow through it to cool the light-emitting diodes 5009 and 5010.

[0057] exist Figure 5A and 5B In the example shown, each reaction chamber 5001, 5101 includes a first inner surface 5018A, 5118A and a second inner surface 5018B, 5118B, on which a photocatalyst 5004 is disposed. The first inner surface 5018A, 5118A and the second inner surface 5018B, 5118B have different parabolic arc profiles, meaning their cross-sections are curve segments with different focal points, and the profiles of the first inner surface 5018A, 5118A are mirror images of the profiles of the second inner surface 5018B, 5118B. The photocatalytic reactor 5000 is thus arranged such that the light-emitting diodes 5009, 5010 of the corresponding sides 5006, 5007 of the LED PCB 5012 illuminate the first inner surface 5018A, 5118A and the second inner surface 5018B, 5118B. Specifically, the first inner surfaces 5018A, 5118A and the second inner surfaces 5018B, 5118B of each reaction chamber 5001, 5101 are arranged symmetrically around the optical axis (O) of the corresponding light-emitting diodes 5009, 5010, such that the first inner surfaces 5018A, 5118A are illuminated by the first half of the light-emitting diodes 5009, 5010, and the second inner surfaces 5018B, 5118B are arranged to be illuminated by the second half of the light-emitting diodes 5009, 5010. The first inner surfaces 5018A, 5118A and the second inner surfaces 5018B, 5118B of each reaction chamber 5001, 5101 are also continuous.

[0058] exist Figure 5A and 5B In this arrangement, the lack of surface features (such as fins or other protrusions) makes it possible, despite being related to Figure 1A , 1B Compared to the arrangements shown in 2A, 2B, 3A, 3B, and 4, the total surface area of ​​the photocatalyst 5004 is reduced. However, the substrates 5003 and 5103 supporting the photocatalyst 5004 are positioned as close as possible to the light sources 5009 and 5010 to maximize the irradiance of the photocatalyst 5004. However, a gap is required between the partition 5005 and the substrates 5003 and 5103 to allow air to pass through the photocatalytic reactor 5000, and optimizing the spacing between the partition 5005 and the substrates 5003 and 5103 provides a thinner air layer, which optimizes the cleanliness and mixing of air within the reaction chambers 5001 and 5101. Figure 5A and 5B In the example shown, the diameter (D) of the partition 5005 is approximately 35 mm, and the maximum distance (S) between the outer surface of the partition 5005 and the substrates 5003 and 5013 is approximately 3 mm. However, this distance may not exceed 10 mm, preferably not more than 7 mm, and more preferably from 1 mm to 7 mm.

[0059] It is also desirable to produce uniform irradiance across the entire catalytic surface, ensuring that the air within the photocatalytic reactor is treated uniformly. However, LEDs do not emit light in a cylindrically symmetrical manner, but rather in a Lambertian distribution. Conventional photocatalytic reactors utilizing LED light sources typically have cylindrical substrates, thus requiring lenses between the LEDs and the substrate to uniformly distribute the light emitted by the LEDs across the substrate surface. Including the lenses increases the cost and size of the LED packaging. To overcome this problem, the applicant has discovered that a more uniform irradiance can be achieved by providing a substrate whose cross-sectional shape is defined by two distinct parabolic arcs. In particular, the use of this parabolic profile facilitates the shaping of the inner surface supporting the catalyst to account for the localized irradiance provided by the LED light source. This inner surface with a parabolic profile reduces the irradiance difference at the inner surface as a function of angle α, thereby providing greater irradiance uniformity at the inner surface containing the photocatalyst. In this respect, the cross-sectional profile shape of each of the first inner surfaces 5018A, 5118A and the second inner surfaces 5018B, 5118B can be defined by a Bézier curve, specifically a quadratic Bézier curve. Therefore, the cross-sectional profile of each of the first inner surfaces 5018A, 5118A and the second inner surfaces 5018B, 5118B can be defined by a three-point Bézier curve, which is defined by the following formula:

[0060] B(t)=(1-t) 2 P0+2(1-t)tP1+t2 P2, t∈[0,1]

[0061] Where P0 is the starting point of the curve, P2 is the ending point of the curve, and P1 is the control point of the curve. Using Bezier curves, a more uniform irradiance can be provided on the photocatalyst surface as a function of angle α.

[0062] As previously described, those skilled in the art will recognize that the above-described photocatalytic reactor can be used to replace the conventional photocatalytic reactor in air handling equipment.

[0063] In the foregoing description, references have been made to elements or components having known, obvious, or foreseeable equivalents, which are incorporated herein as if described separately. The true scope of the invention should be determined with reference to the claims, which should be interpreted as including any such equivalents. The reader will also understand that elements or features of the invention described as preferred, advantageous, convenient, etc., are optional and do not limit the scope of the independent claims. Furthermore, it should be understood that while such optional elements or features may be beneficial in some embodiments of the invention, they may be undesirable in other embodiments and therefore may be absent.

Claims

1. A photocatalytic reactor, comprising: A reaction chamber, arranged to receive an airflow containing one or more airborne pollutants, the reaction chamber comprising: A first inner surface, a second inner surface, a photocatalyst disposed on both the first inner surface and the second inner surface for photocatalytic degradation of one or more pollutants, and a light source arranged to irradiate at least a portion of the photocatalyst disposed on the first inner surface and the second inner surface; The first inner surface and the second inner surface have different parabolic arc contours, and the contour of the first inner surface is a mirror image of the contour of the second inner surface. The light source includes a plurality of light-emitting diodes, each of which is arranged to illuminate at least a portion of both the first inner surface and the second inner surface, and the first inner surface and the second inner surface are arranged symmetrically about the optical axis of each of the plurality of light-emitting diodes. The reaction chamber is longitudinal, and the plurality of light-emitting diodes are longitudinally aligned.

2. The photocatalytic reactor according to claim 1, wherein, The first inner surface and the second inner surface are continuous.

3. The photocatalytic reactor according to claim 1, wherein, The plurality of light-emitting diodes are arranged such that each light-emitting diode illuminates different portions of both the first inner surface and the second inner surface.

4. The photocatalytic reactor according to any one of claims 1 to 3, wherein, The reaction chamber includes an air inlet and an air outlet, and is arranged such that an airflow passing between the air inlet and the air outlet contacts the photocatalyst.

5. The photocatalytic reactor according to any one of claims 1 to 3, wherein, The reaction chamber includes at least one layer of transparent material that separates the photocatalyst from the light source.

6. The photocatalytic reactor according to claim 5, wherein, The first inner surface and the second inner surface are spaced apart from the outermost surface of at least one layer of transparent material by a maximum distance not exceeding 10 mm.

7. The photocatalytic reactor according to claim 5, wherein, The first inner surface and the second inner surface are spaced apart from the outermost surface of at least one layer of transparent material by a maximum distance not exceeding 7 mm.

8. The photocatalytic reactor according to claim 5, wherein, The first inner surface and the second inner surface are spaced apart from the outermost surface of at least one layer of transparent material by a maximum distance ranging from 1 mm to 7 mm.

9. The photocatalytic reactor according to claim 1, wherein, The photocatalytic reactor comprises multiple reaction chambers.

10. The photocatalytic reactor according to claim 9, wherein, The plurality of reaction chambers are distributed around a common axis, each reaction chamber is arranged such that the first inner surface and the second inner surface face inward, and the light source is centered relative to the first inner surface and the second inner surface.

11. The photocatalytic reactor according to claim 9 or 10, wherein, The multiple photocatalytic reaction chambers are arranged in a continuous manner.

12. The photocatalytic reactor according to claim 9 or 10, wherein, The plurality of reaction chambers are arranged such that the arrangement is rotationally symmetric about a common axis.

13. The photocatalytic reactor according to claim 12, wherein, The plurality of reaction chambers are arranged such that the arrangement has n-fold rotational symmetry about the common axis, where n is equal to the number of reaction chambers.

14. An air treatment apparatus comprising a photocatalytic reactor according to any one of claims 1 to 13.

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