Fluid purification system and method

Abstract

An in-line fluid purification system uses a jacket (26) surrounding a fluid passageway (28), formed of a UV transmissive material. The jacket (26) may be surrounded by a UV reflective material (30). UV radiation (20) is coupled into the jacket (26), and the jacket (26) disperses and reflects the radiation over the entire cross section of the passageway (28). In this way, UV illumination of the full cross section of a fluid passageway (28) is ensured.

Claims

1. An in-line fluid purification system for purifying a fluid or fluid flow, comprising: a jacket surrounding a fluid passageway, formed of a UV transmissive material; one or more UV LEDs for coupling UV radiation into the jacket, wherein the jacket is an optical element adapted to couple UV radiation from the one or more UV LEDs around the outer periphery of the passageway by optimizing the distribution of the UV radiation emitted by the one or more UV LEDs, wherein the jacket comprises an annular waveguide, and wherein the annular waveguide comprises a UV scattering material.

2. A system as claimed in claim 1, wherein the UV scattering material comprises polycrystalline aluminum oxide, quartz, UV transparent glass, silicone, fluorinated ethylene propylene, ethylene tetrafluoroethylene or polytetrafluoroethylene.

3. A system as claimed in claim 1, comprising: a single UV LED; or multiple UV LEDs.

4. A system as claimed in claim 1, wherein the jacket is for surrounding two or more passageways.

5. A system as claimed in claim 1, further comprising a UV reflecting coating around the outside of the jacket, wherein the one or more UV LEDs is within the jacket, wherein the UV reflecting coating is partly diffuse reflective.

6. A system as claimed in claim 5, wherein the reflecting coating comprises or is connected to a heat dissipation unit.

7. A system as claimed in claim 6, wherein the reflecting coating is for fitting flush within the pipe of a tap for thermal coupling to the pipe of the tap.

8. A tap comprising a system as claimed in claim 1 mounted within a fluid passageway of the tap.

9. An in-line fluid purification method for purifying a fluid or fluid flow, comprising: surrounding a fluid passageway with a jacket formed of a UV transmissive material; coupling UV radiation into the jacket from a UV LED, wherein the jacket is an optical element adapted to couple UV radiation from the UV LED all around the outer periphery passageway by optimizing the distribution of the UV radiation emitted by the UV LED, wherein the jacket comprises an annular waveguide, and wherein the annular waveguide comprises a UV scattering material.

10. A method as claimed in claim 9, comprising surrounding two or more passageways with the jacket.

11. A method as claimed in claim 9, comprising reflecting UV radiation reaching the outside of the jacket back into the jacket.

12. A method as claimed in claim 9, comprising dissipating heat from the outside of the jacket by coupling to a pipe of a tap.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Examples of the invention will now be described in detail with reference to the accompanying drawings, in which:

(2) FIGS. 1A to 1C show a non-purified water tap and two approaches to water tap purification;

(3) FIGS. 2A to 2C show in cross section perpendicular to the flow direction three approaches to water purification;

(4) FIGS. 3A to 3C show in cross section parallel to the flow direction three approaches to water purification corresponding to FIGS. 2A to 2C;

(5) FIG. 4 shows a further approach to water purification; and

(6) FIG. 5 shows a water purification system applied to a tap.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(7) The invention provides an in-line fluid purification system which uses a jacket surrounding a fluid passageway, formed of a UV transmissive material. The jacket may be surrounded by a UV reflective material. UV radiation is coupled into the jacket, and the jacket disperses and reflects the radiation over the entire cross section of the passageway. In this way, UV illumination of the full cross section of a fluid passageway is ensured. This may be advantageous in increasing the flow rate of liquid that it is possible to irradiate using this device. An increase in flow rate requires that the treatment time of each unit (ml, liter, mm.sup.2, cm.sup.2, m.sup.2 etc.) of fluid is reduced. This optimized distribution of radiation may also mean that fewer LEDs are required to maintain an acceptable fluid flow and treatment rate.

(8) The system may comprise a UV-C LED. However, the same approach may be used for other UV wavelengths, for example UV-A radiation in combination with a photo catalyst which then creates radicals in water.

(9) FIG. 1A shows a tap 10 mounted through a work surface 12, with no UV treatment. As a result, microbiological contamination 13 exists. FIG. 1B shows a UV treatment head 14 at the spout of the tap and FIG. 1C shows an in-line UV treatment unit 16 beneath the work surface 12. The provision of treatment below the work surface means that microbiological contamination 13 still exists in the pipe leading to the tap outlet. It would therefore be desirable to have a UV-C treatment system at the tap outlet, but for such a system to be aesthetically acceptable, it needs to be compact.

(10) The use of UV-C LEDs enables a small compact water treatment unit to be provided. However, to illuminate the full cross section of a water flow, typically many UV-C LED sources are needed around the water passageway, which increases cost and requires a large amount of space, which will either increase the outer diameter of the device or decrease the size of the bore that is provided for the fluid to flow through. If the external diameter of the device is increased, the physical size of the tap or pipe that the device is located in must, correspondingly, be increased. If the bore of the fluid passageway is decreased this will limit the amount of fluid that can be passed through the device in a unit of time (the flow rate).

(11) FIG. 2 shows three examples of UV-C treatment system, in cross section perpendicular to the flow direction along a passageway. FIG. 3 shows corresponding cross sections in a plane parallel to the flow direction.

(12) FIGS. 2A and 3A show a UV-C LED 20 mounted within a fluid pipe for irradiating a water flow along the pipe. The LED is mounted generally at an outer edge of the inside of the pipe and faces radially inwardly. This provides illumination of the cross section of the fluid pipe 22 but there are regions 24 where there is a low intensity of UV radiation.

(13) FIGS. 2B and 3B show an arrangement in accordance with a first example of the invention.

(14) A jacket 26 (which may also be described as a ring, sleeve, surround, or outer enclosure) surrounds a fluid passageway 28. The jacket may be within an outer pipe, or it may itself define the outer periphery. Thus, the jacket itself defines and surrounds the fluid passageway or passageways. The jacket is formed of a UV transmissive material by which it is meant that UV-C radiation in particular is able to propagate through the material of the jacket, and therefore around the jacket, increasing the distribution of the radiation by optimizing the distribution of the radiation.

(15) The UV-C radiation can propagate at least from one side of the jacket to the other side of the jacket, and more preferably can propagate around at least one full circumference, or around at least 2, 5 or 10 full circumferences before absorption. By way of example, the transmissive material of the jacket may have a UV transmission of at least 60% per cm, for example at least 70%, 80%, 90% or even 95% transmission per cm.

(16) In addition, there are reflections at the inner and outer circumferential boundaries of the jacket so that the UV-C radiation is able to propagate around the full periphery of the jacket even when the UV-C radiation is only provided from one angular location.

(17) The main functions of the jacket are to provide a location for the UV-C LED 20, to guide UV-C radiation to the fluid in the passageway 28 and to disperse radiation so there are no dark spots. As will be explained below, the jacket also allows for complex dispense points with multiple passageways, using only one LED.

(18) A reflector is provided at the exterior of the jacket which conserves radiation that would otherwise be absorbed outside the jacket.

(19) The UV-C LED is placed within the jacket, namely between the radial inner interface at the passageway boundary and the radial outer surface of the jacket. The jacket thus isolates the LED from the fluid in the passageway. In particular, the jacket may be a solid material. Electrical connections may be made to the UV-C LED from the outside of the jacket. The jacket for example, may comprise a molded waterproof solid.

(20) The jacket conducts the UV-C radiation of the UV-C LED 20 into water or air standing in the passageway or water flowing along the passageway just before it leaves an outlet. Thus, the fluid may be a liquid or a gas. When standing fluid is purified, the jacket forms a barrier between the exterior of the passageway and the interior of the passageway. For the example of a tap, when the tap is turned off, there may either be water or air standing in the end of the tap, depending primarily on the diameter of the passageway, the capillary forces present and the direction in which the tap passageway points, it can be seen that a tap having, for example, a horizontal pipe before an angled outlet would have different fluid retention properties from a tap wherein the fluid passageway simply points in a downwards direction.

(21) In the example of FIGS. 2B and 3B, the jacket is formed from a UV-C scattering material. The scattering serves to convert the directional output of the UV-C LED into a more general radiation pattern. As shown, the UV-C LED faces radially inwardly towards the passageway 28. Some UV radiation passes directly into the passageway for partial or complete absorption by the water. Unabsorbed radiation reaches the jacket at the opposite side, and is then scattered with a random angle. This random angle scattering makes the overall radiation more uniform. Other UV radiation initially directed away from the passageway 28 is scattered by the jacket and redirected towards the passageway 28.

(22) A UV reflector 30 is preferably provided on the outside periphery of the jacket so that any UV-C radiation which reaches the outer periphery (with or without having been scattered) is reflected back into the jacket. The reflector is for example at least partly diffuse reflective.

(23) The reflector is for example, formed from aluminum, chromium or alumina (aluminum oxide).

(24) Heat is dissipated from the outside of the jacket. This may be achieved by the water pipe itself. However, the material of the jacket itself, such as polycrystalline aluminum oxide (PCA), may function as a heat transfer layer to transfer heat from the UV-C LED to the water.

(25) The jacket may surround and define one or more passageways. FIGS. 2B and 3B show a second example with two passageways 28a, 28b. These passageways then connect to separate water pipes.

(26) The passageways formed in the inside of the jacket may be in direct contact with the fluid. However, it is also possible for an internal water pipe to be connected within the jacket. An internal water pipe running through the jacket may be formed from a UV transparent material such as quartz, silicone, or UV-C transparent glass. It may also comprise fluorinated ethylene propylene (known as Teflon (Trade Mark) FEP) or ethylene tetrafluoroethylene (ETFE) or polytetrafluoroethylene (PTFE).

(27) The jacket may be formed as a molded component.

(28) In both examples above, the UV scattering material of the jacket for example comprises polycrystalline aluminum oxide (PCA). PCA is translucent for UV-C so that the radiation is scattered and reflected. Other examples of material for the jacket include UV-C transparent materials such as UV-C transparent glass, quartz (SiO2) or silicone. Other materials which may be used, again include fluorinated ethylene propylene (known as Teflon (Trade Mark) FEP) or ethylene tetrafluoroethylene (ETFE) or polytetrafluoroethylene (PTFE).

(29) Where these materials are transparent (rather than translucent) they may be made to scatter to the desired degree by adding scattering elements such as air bubbles.

(30) The system may comprise a single UV LED, and the jacket. This enables a low cost and compact system.

(31) The examples above make use of a scattering medium. An alternative is to use a waveguide approach as shown in FIG. 4 in which the jacket 26 is formed from a UV transparent (and non-scattering) medium.

(32) In this case, the jacket does not have to be scattering. A diffusive reflector around the jacket may be used to make the radiation inside the passageway more homogeneous as desired. Possible materials for the jacket again include UV-C transparent materials such as UV-C transparent glass, quartz (SiO2) or silicone.

(33) The UV-C LED in this example provides UV radiation in a generally tangential direction. In FIG. 4, the jacket functions as a waveguide. There are reflections at the outer periphery, and these may be total internal reflections or specular reflections or diffuse reflections from the reflecting coating.

(34) The UV radiation enters the passageway by a refractive interface between the jacket and the fluid in the passageway (which interrupts total internal reflection). If a diffuse reflecting outer coating is used, the radiation will approach the interface with all angles of incidence. Outcoupling structures may again, be provided on the surface of the fluid passageway. These outcoupling structures may be surface deformations such as ridges or patterns, they may be lenses, for example, micro optic lenses (MLO), they may be dots of paint or they may be patterns that are etched on the surface, for example, laser etched.

(35) By way of example, there may be two UV-C LEDs 20a, 20b facing in opposite directions at an LED module 40. There may instead be a single UV-C LED.

(36) As explained above, the outside of the jacket may have a reflecting coating. It may also perform a heat dissipation function. For example, it may be thermally coupled to a tap body. The coating thus provides heat spreading. There may instead be a separate reflector layer and heat spreading layer. There may be only a heat spreading layer (so that reflection is carried out by a housing in which the system is installed) or there may be only a reflector (so that heat dissipation is implemented by a housing in which the system is installed).

(37) FIG. 5 shows a tap outlet 50 in which the system described above (shown as 52) is provided at the exit opening. The jacket (and its reflecting coating if provided) is then fitted flush within the pipe of the tap. The tap pipe may itself function as the reflecting coating.

(38) The system may be a unit which fits within another fluid pipe as shown in FIG. 5, for example with an O-ring seal around the unit. However, it may instead be connected in-line to a fluid pipe, with a pipe connection between the passageway at one or both sides of the system.

(39) The jacket may be formed by sintering a molded material into the desired shape.

(40) For an in-flow system, the purification system may be actuated automatically in response to the detection of fluid flow, or else based on detection of when a flow control device (i.e. tap) has been turned on by a user. It may also be used only for cold water and deactivated for hot water for which the purification may not be needed. The purification may be implemented for hot water as well, if thermal management issues are considered.

(41) In a system which provides purification in advance of a fluid flow, the UV LED may be operated periodically or continuously to maintain a barrier for micro-organisms entering from the outside. This means the system can be effective with a lower power LED since in-flow purification is not then needed.

(42) The invention is of interest for taps and other water dispensing outlets or machines.

(43) Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.