APPARATUS FOR PURIFYING LIQUID BY ULTRAVIOLET LIGHT IRRADIATION

Abstract

An apparatus for purifying liquid comprises a substantially tubular irradiation chamber (100) and a plurality of UV-LEDs (110) projecting ultraviolet radiation into it so as to irradiate the flow (106) of liquid being passed through it, where each of the UV-LEDs (110) is disposed upon the irradiation chamber (100) so that it is illuminated by at least one other of the plurality of UV-LEDs (110).

Claims

1. An apparatus for purifying liquid, comprising a substantially tubular irradiation chamber adapted to conduct a flow of liquid therethrough, and a plurality of UV-LEDs disposed upon and configured to project ultraviolet radiation into the irradiation chamber and thereby irradiate the flow of liquid, characterized in that the plurality of UV-LEDs are configured such that each of the UV-LEDs is directly illuminated by the ultraviolet irradiation emitted by at least one other of the UV-LEDs.

2. The apparatus of claim 1, wherein the plurality of UV-LEDs are distributed along a length of the irradiation chamber with a substantially uniform linear spacing.

3. The apparatus of claim 1, wherein the plurality of UV-LEDs are distributed along the perimeter of the irradiation chamber with a substantially uniform angular spacing about a longitudinal axis of the irradiation chamber.

4. The apparatus of claim 1, wherein each of the UV-LEDs is disposed upon the irradiation chamber directly opposite another of the UV-LEDs, thereby defining a plurality of UV-LED pairs.

5. The apparatus of claim 4, wherein the UV-LED pairs are distributed along a length of the irradiation chamber with a substantially uniform linear spacing, and along the perimeter of the irradiation chamber with a substantially uniform angular spacing about a longitudinal axis of the irradiation chamber.

6. The apparatus of claim 1, wherein the distance along a wall of the irradiation chamber between any two adjacent UV-LEDs is less than or equal to twice a width of the irradiation chamber multiplied by the tangent of one-half the angle of emission of the UV-LEDs.

7. The apparatus of claim 1, wherein the irradiation chamber has a substantially constant cross-section.

8. The apparatus of claim 7, wherein the irradiation chamber has a substantially circular cross-section.

9. The apparatus of claim 1, wherein the UV-LEDs have an angle of emission equal to or greater than 90.

10. The apparatus of claim 9, wherein the UV-LEDs have an angle of emission between 110 and 130 inclusive.

11. The apparatus of claim 1, wherein at least part of an interior surface of the irradiation chamber is substantially reflective to ultraviolet radiation.

12. The apparatus of claim 1, wherein the interior surface of the irradiation chamber is at least partially coated in a substance which is substantially reflective to ultraviolet irradiation.

13. The apparatus of claim 1, wherein the plurality of UV-LEDs are disposed upon an exterior surface of the irradiation chamber.

14. A beverage dispensing apparatus comprising an apparatus for purifying liquid comprising a substantially tubular irradiation chamber adapted to conduct a flow of liquid therethrough, and a plurality of UV-LEDs disposed upon and configured to project ultraviolet radiation into the irradiation chamber and thereby irradiate the flow of liquid, the plurality of UV-LEDs are configured such that each of the UV-LEDs is directly illuminated by the ultraviolet irradiation emitted by at least one other of the UV-LEDs.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0041] FIGS. 1A and 1B are respectively longitudinal and lateral section views of an apparatus for purifying liquid, according to a first embodiment;

[0042] FIGS. 2A and 2B are respectively a side view and a lateral section view of an apparatus for purifying water according to a second embodiment; and

[0043] FIGS. 3A and 3B are respectively a side view and a lateral section view of an apparatus for purifying water according to a third embodiment.

DETAILED DESCRIPTION

[0044] For a complete understanding of the present invention and the advantages thereof, reference is made to the following detailed description of the invention.

[0045] It should be appreciated that various embodiments of the present invention can be combined with other embodiments of the invention and are merely illustrative of the specific ways to make and use the invention and do not limit the scope of the invention when taken into consideration with the claims and the following detailed description.

[0046] Further, this document describes groups of components, which are referenced with both a numeral and a letter, e.g. widgets 10A, 10B, 10C . . . . When such terminology is employed, it should be understood that the components in the group are substantially identical; that when the both the numeral and letter are used it should be understood as referencing individual members of the group, while when only the numeral is used it should be understood as referencing the group in its entirety.

[0047] As used in this specification, the words comprises, comprising, and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean including, but not limited to.

[0048] Any reference to prior art documents in this specification is not to be considered an admission that such prior art is widely known or forms part of the common general knowledge in the field.

[0049] The invention is further described with reference to the following examples. It will be appreciated that the invention as claimed is not intended to be limited in any way by these examples.

[0050] The main principle of the invention is first described.

[0051] FIGS. 1A and 1B are respectively longitudinal and lateral section views of a device for purifying liquid. In FIG. 1A, the device is represented by the irradiation chamber 100, which is a substantially tubular, elongated structure having an inlet 102 and an outlet 104. The inlet 102 is adapted to receive a flow 106 of liquid, which is conducted through the cavity 108 of the irradiation chamber and out the outlet 104.

[0052] While the flow 106 is in the cavity 108 of the irradiation chamber 100, it is irradiated with ultraviolet light emitted by the UV-LEDs 110. The UV-LEDs are disposed upon an exterior surface 112 of the irradiation chamber 100, which is transparent to ultraviolet light where the UV-LEDs 110 are disposed. The In this way, the flow 106 of liquid is irradiated by each of the UV-LEDs 110 in turn, as it flows through the irradiation chamber 100.

[0053] Each of the UV-LEDs 110 emits ultraviolet light in a conical emission pattern 114, which has its point at the UV-LED 110 and gradually expands outwards as it propagates across the cavity 108 of the irradiation chamber 100. In FIG. 1A, each of the emission patterns 114 is given a different cross-hatching, to illustrate their overlapping nature.

[0054] In this embodiment, the UV-LEDs 110 are disposed along the irradiation chamber 100 with a consistent linear spacing, such that as one moves along the longitudinal axis 116 of the irradiation chamber 100, successive UV-LEDs 110 are separated by a distance 1/2s, with successive UV-LEDs 110 on one side being thus separated by a distance of s. The value of s is chosen as a function of the diameter of the irradiation chamber 110 and the angle of each emission cone 114 so that, as depicted here, each emission cone extends to an edge of at least one of the UV-LEDs 110 opposite. In this way, any dead zone around the UV-LEDs is minimized.

[0055] In most embodiments, it will be advantageous to ensure that the internal surface 118 of the irradiation chamber 100 is reflective to ultraviolet light. This will further serve to reduce, or even eliminate, any dead zones in the irradiation chamber 110, in that the portions of the volume of the irradiation chamber 100 which are not directly illuminated by one of the UV-LEDs 110 are irradiated by the reflected light.

[0056] In addition, this reflective property improves the sterilization efficiency of the irradiation chamber 100, in that UV light which does not irradiate a pathogenic microorganism directly can still do so after reflecting off of the interior surface 118 one or more times.

[0057] In practice, this reflective property can be achieved by the deposition of a coating 120 upon the interior surface 118 of the irradiation chamber 100, which is here only partially depicted in the interest of clarity. This coating can be, for example, a layer of a polymer such as polytetrafluoroethylene (PTFE), a metallic coating such as gold or silver, or some combination of these or other appropriate substances.

[0058] The means by which this coating is applied will depend on the particulars of the embodiment. For example, the irradiation chamber may be provided as transparent glass, and the coating applied by vapor deposition upon the internal surface of the chamber.

[0059] FIG. 1B offers further illustration of this, in the form of the section A-A at the section line shown in FIG. 1A. Here, it can be seen that a flow (not shown) of fluid passing through the irradiation chamber 100 will be irradiated throughout its section, as the UV-LEDs 110 illuminate the entirety of its circular cross-section. Thus, even when the dead zones cannot be totally eliminated from the irradiation chamber 100, the flow of the liquid through the chamber will ensure complete irradiation.

[0060] FIG. 2A is a side view of an apparatus for purifying water according to a second embodiment. In this embodiment, the irradiation chamber 200 is, as in the previous embodiment, provided with an inlet 202 and an outlet 204 adapted to conduct a flow 206 of liquid through the irradiation chamber 200. Ultraviolet radiation is projected into the cavity 208 of the irradiation chamber 200 by the UV-LEDs 210.

[0061] The UV-LEDs 210 are disposed upon the irradiation chamber 200 with a substantially uniform spacing both in a linear sense along the longitudinal axis 216, and in an axial sense about said longitudinal axis 216. The UV-LEDs 210 are thus arranged upon the irradiation chamber 200 in a helical arrangement that realizes the advantages described above.

[0062] FIG. 2B is a lateral section view of the irradiation chamber 200 through the section line B-B depicted in FIG. 3A. In FIG. 2B, it is seen that the angular spacing of the UV-LEDs 210 about the longitudinal axis 216 (here designated by the symbol is substantially constant between each of the UV-LEDs 210. This Figure also shows the wide-angled conical emission patterns 214.

[0063] Thus, it can be seen that in any particular application, the propagation of the UV light within the irradiation chamber can be controlled by modifying the parameters thus far described, including the angle of the emission patterns, the longitudinal spacing between UV-LEDs, the angular spacing of the UV-LEDs, the total active length of the irradiation chamber, and the number of the UV-LEDs.

[0064] The user can thus adapt the apparatus to the particular needs of the application for which it is destined; for instance, an application where a high degree of sterilization is desired such as a dispenser for infant formula, can be provided with many UV-LEDs with tight linear and angular spacing, while other applications where the need for sterilization is not so acute may be provided with fewer UV-LEDs and wider spacing.

[0065] FIGS. 3A and 3B are respectively a side view and lateral section view of a liquid purifying apparatus according to a third embodiment. As in the previous two embodiments discussed above, the apparatus comprises an irradiation chamber 300, provided with an inlet 302 and an outlet 304 configured to direct a flow 306 of liquid through the cavity 308 of the irradiation chamber 300. The irradiation chamber is further provided with a plurality of UV-LEDs 310, which project into the irradiation chamber 310 as in the two embodiments discussed above.

[0066] In this embodiment, the UV-LEDs 310 are arranged in pairs 350A, 350B, 350C, and 350D. Each pair 350 is disposed so that the two UV-LEDs project upon each other, such that they are at the same linear position with respect to the longitudinal axis 316, but have a 180 angular separation about said longitudinal axis 316. The UV-LEDs 310 in each of the pairs 350 will thereby mutually illuminate each other, eliminating any dead zone around them.

[0067] Furthermore, the pairs 350 of UV-LEDs 310 are disposed along the length of the irradiation chamber 300 with a substantially constant linear spacing, and about the longitudinal axis 316 of the irradiation chamber 300 with a substantially constant axial spacing, substantially as described in relation to the two previous embodiments. This spacing ensures that the UV-LEDs 310 of each pair 350 are also illuminated by at least one UV-LED 310 of another pair 350, in the same way as described above.

[0068] In this way, a thorough purification of the flow 306 of liquid is achieved. Moreover, because each UV-LED 310 is illuminated both by its complement UV-LED 310 in its own pair 350, and by a UV-LED 310 in another one of the pairs 350, there is achieved a redundancy should one of the UV-LEDs 310 fail. In this way, the reliability of the system is improved.

[0069] FIG. 3B is a lateral section view of the irradiation chamber 300, taken at the section line C-C as depicted in FIG. 3A. Here, it can be seen that the angular separation a between the UV-LEDs 310 of the pair 350B is 180; i.e. that the UV-LEDs 310 of the pair 350B are diametrically opposed from one another. While not depicted for clarity, this angular relation is the same for each of the other pairs 350A, 350D of UV-LEDs 310.

[0070] Although the invention has been described by way of example, it should be appreciated that variations and modifications may be made without departing from the scope of the invention as defined in the claims. Furthermore, where known equivalents exist to specific features, such equivalents are incorporated as if specifically referred in this specification.

[0071] In a general sense, elements described in the foregoing disclosure should not be taken as being limited to the combinations and configurations described in the foregoing example embodiments. Recombination of the elements described above according to the particulars of each application should be considered as envisioned when not in direct contradiction to this disclosure.

[0072] In particular, it should be recognized that, while the above embodiments describe embodiments where there is a constant flow of liquid through the irradiation chamber, the invention is equally directed towards embodiments where said flow is not constant, i.e. so-called static reactors. In such an embodiment, it may be that a volume of liquid flows into the irradiation chamber, is irradiated, and then subsequently flows out. The foregoing disclosure should not, therefore, be construed as being limited to constant-flow apparatuses such as the embodiments discussed above.

[0073] Also, while it is envisioned that an apparatus according to the present invention be integrated into a beverage dispensing apparatus, it may equally be possible to employ such an apparatus in other applications, for example in commercial, industrial, medical, or other such applications where reliable purification of a liquid is sought. In particular, it may be advantageous to incorporate such an apparatus into devices such as beverage vending machines, coffee or tea dispensers, or dispensers for prepared food such as soups, cereals, infant formula, or the like.

[0074] It should thus be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is therefore intended that the appended claims be considered as including any embodiment which is derived at least partially from it.