METHOD AND APPARATUS FOR PURIFYING LIQUID

Abstract

An apparatus (100) for purifying liquid comprises an irradiation chamber (102) upon which are disposed a plurality of UV-LEDs (112) which irradiate a flow (110) of liquid as it passes therethrough; a coolant conduit (104) is disposed about said irradiation chamber (102) and UV-LEDs (112), which conducts a flow (126) of a coolant fluid through it thereby cooling the flow (110) of liquid and the plurality of UV-LEDs (112).

Claims

1. An apparatus for purifying a liquid, comprising a substantially tubular irradiation chamber adapted to conduct a flow of liquid therethrough, and a plurality of UV-LEDs disposed upon the irradiation chamber and adapted to irradiate said-the flow of liquid, the apparatus comprises a coolant conduit disposed about the irradiation chamber and the UV-LEDs, the coolant conduit being adapted to circulate a flow of a coolant fluid about the irradiation chamber.

2. The apparatus of claim 1, comprising a first tube disposed coaxially about the irradiation chamber, and a second tube disposed coaxially about the first tube, the first and second tubes thereby defining between them a substantially annular space at least partially constituting the coolant conduit.

3. The apparatus of claim 1, wherein the coolant conduit is a tube at least partially configured as a helix having an axis substantially coincident with a longitudinal axis of the irradiation chamber.

4. The apparatus of claim 1, wherein the coolant fluid is water.

5. The apparatus of claim 1, wherein the coolant fluid is a refrigerant gas.

6. The apparatus of claim 5, wherein the cooling conduit at least partially constitutes an evaporator of a refrigeration system.

7. The apparatus of claim 1, wherein the irradiation chamber and the coolant conduit define an interstitial space between them.

8. The apparatus of claim 7, wherein the interstitial space is at least partially filled with a heat-conducting material.

9. The apparatus of claim 1, wherein the cooling conduit is in fluid communication with a cavity of the irradiation chamber.

10. A beverage dispenser 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 the irradiation chamber and adapted to irradiate the flow of liquid, the apparatus comprises a coolant conduit disposed about the irradiation chamber and the UV-LEDs, the coolant conduit being adapted to circulate a flow of a coolant fluid about the irradiation chamber.

11. A method for the purification of a liquid, comprising the steps of: providing a substantially tubular irradiation chamber adapted to conduct a flow of liquid therethrough, and a plurality of UV-LEDs disposed upon the irradiation chamber and adapted to irradiate the flow of liquid; providing a flow of a coolant fluid; directing the flow of a coolant fluid through a coolant conduit disposed about the irradiation chamber and the UV-LEDs, thereby cooling the irradiation chamber and the UV-LEDs; and directing a flow of liquid through the irradiation chamber, thereby irradiating the flow of liquid.

12. The method of claim 11, wherein the flow of coolant fluid is directed through the coolant conduit in a direction substantially opposite the direction of the flow of liquid through the irradiation chamber.

13. The method of claim 11, wherein the coolant fluid is water.

14. The method of claim 13, wherein the flow of coolant fluid directed through the coolant conduit is also the flow of liquid irradiated in the irradiation chamber.

15. The method of claim 14, wherein the flow of liquid is chilled prior to being directed through the coolant conduit and the irradiation chamber.

16. The method of claim 11, wherein the coolant fluid is a refrigerant gas, the coolant conduit thereby constituting at least part of an evaporator of a refrigeration system, and wherein the flow of water is cooled by the flow of refrigerant gas in the evaporator.

17. The method of claim 11, wherein the flow of coolant fluid is provided at a temperature at or below 10 Celsius.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0053] FIG. 1 is a section view of an apparatus for purifying liquid according to a first embodiment;

[0054] FIG. 2 is a section view of an apparatus for purifying liquid according to a second embodiment; and

[0055] FIG. 3 is a side view of an apparatus 300 for purifying liquid, according to a third embodiment.

DETAILED DESCRIPTION

[0056] For a complete understanding of the present invention and the advantages thereof, reference is made to the following detailed description of the invention.

[0057] 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. In the present description, the following words are given a definition that should be taken into account when reading and interpreting the description, examples and claims.

[0058] In particular, the initialism UV-LED is employed for the sake of convenience and brevity to stand for Ultraviolet Light-Emitting Diode, and should not be construed as carrying any other meaning.

[0059] Furthermore, the term irradiate and variants thereof are to be understood in the context of sterilization processes by ultraviolet irradiation as described above, and as importing the technical characteristics of such processes.

[0060] Also, the term refrigerant gas should be understood as describing those substances which are employed as the working fluid in a refrigeration cycle; and which as a category are generally, but not necessarily, in a gaseous phase at standard temperature and pressure. Such substances need not necessarily be in the form of a gas at every phase of the refrigeration cycle, or in any particular phase of said cycle, but may in fact be present in the form of a gas, a liquid, or a combination of gas and liquid. The term refrigerant gas is thus a simplification for the sake of convenience.

[0061] Finally, 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.

[0062] 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.

[0063] 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.

[0064] The main principle of the invention is first described.

[0065] FIG. 1 is a section view of an apparatus 100 for purifying a liquid according to a first embodiment of the invention. The apparatus 100 comprises globally an irradiation chamber 102 and a coolant conduit 104, which will be discussed in turn.

[0066] The irradiation chamber 102 is provided with an irradiation chamber inlet 106 and an irradiation chamber outlet 108, such that a flow 110 of liquid is conducted through the irradiation chamber 102 in the manner depicted. About the perimeter of the irradiation chamber 102 are disposed a plurality of UV-LEDs 112. The UV-LEDs 112 are disposed so as to project UV light 114 into the irradiation chamber 102. In this way, the flow 110 of liquid is irradiated as it passes through the irradiation chamber 102, being thereby sterilized.

[0067] It will be readily recognized that the positioning of the UV-LEDs 112 as depicted here is simplified for considerations of clarity, and that in practice it may be preferable to adopt a different distribution thereof. It may, for instance, be preferable to dispose the UV-LEDs with a substantially uniform spacing along the length and around the circumference of the irradiation chamber, so as to more uniformly distribute the irradiation and heat emission of said UV-LEDs.

[0068] The coolant conduit 104 is formed by the tubular inner wall 116 which is disposed about the irradiation chamber 102, and the tubular outer wall 118 which is disposed about the inner wall 116. The irradiation chamber 102, and the inner wall 116 and outer wall 118 are all disposed substantially coaxially about the longitudinal axis 120.

[0069] The coolant conduit 104 is further provided with a coolant inlet 122 and a coolant outlet 124. When a flow 126 of a coolant fluid is introduced into the coolant inlet 122, it will circulate through the coolant conduit 104 about the irradiation chamber 102, and then out the coolant outlet 124. As the flow 126 of coolant circulates through the coolant conduit 104, it absorbs heat from the UV-LEDs 112 and the flow 110 of liquid.

[0070] The apparatus 100 may be configured so that the flow 126 of coolant runs in a direction counter to that of the flow 110 of liquid. Such a counter-flow arrangement will improve the cooling efficiency of the apparatus 100.

[0071] The inner wall 116 is not disposed flush against the irradiation chamber 102, but is instead slightly larger so as to accommodate the UV-LEDs 112. This results in an interstitial space 128 between the irradiation chamber 102 and the inner wall 116 of the coolant conduit 104.

[0072] The interstitial space 128 permits the passage of the electrical wires 130 to the UV-LEDs 112, thereby facilitating the supply of electricity to them. Since the electrical wires 130 do not penetrate the irradiation chamber 102 or the coolant conduit 104, the apparatus 100 is rendered essentially leak-proof. Moreover, maintenance of the UV-LEDs 112 and the electrical wiring 130 is facilitated; the user need only slide the inner wall 116 and the outer wall 118 of the coolant conduit 104 along the longitudinal axis 120 to expose them for servicing.

[0073] The interstitial space 128 may be left exposed to the atmosphere, or it may preferably be filled with a heat-conducting material 132. The heat-conducting material 132 may be thermal grease or paste, gel, cream, putty, or the like. When packed into the interstitial space 128, the heat-conducting material 132 will facilitate the conduction of heat from the flow 110 of liquid, the irradiation chamber 102, and the UV-LEDs 112 into the flow 126 of coolant within the coolant conduit 104. The inner wall 116 may also be configured such that it is in contact with the UV-LEDs 112.

[0074] Of course, the person of skill in the art will readily recognize how the precise configuration and dimensions of the irradiation chamber and the coolant conduit can be adapted to the needs of any particular application.

[0075] In particular, the volume of the irradiation chamber 102 and of the coolant conduit 104 is preferably, though not necessarily, adapted to the flow rate of the flow 110 of liquid through the apparatus 100. In addition, as the heat transfer rate from the irradiation chamber 102 and UV-LEDs 112 to the flow 126 of coolant is dependent at least in part on the area of interface between these components, the volume of the coolant conduit 104 should be no larger than is necessary to provide a sufficient mass flow rate of the flow 126 of coolant through the apparatus 100.

[0076] In a practical embodiment, the apparatus 100 could be integrated into a beverage dispensing apparatus. Such a dispensing apparatus could be simply a water fountain, or a machine for preparing food or drink such as soup or coffee. Such an apparatus could comprise, in addition to the apparatus 100, chillers or refrigeration units, storage tanks, pumps, power supplies, boilers and/or vaporizers, dispensers, and any other such material as would be necessary or desirable for integration into a beverage dispensing unit. Beverage dispensing apparatuses are generally well known in the art, and as such are not discussed further.

[0077] As a result, the dimensions and form of the irradiation chamber may vary according to the application in which it is to be employed. For instance, a point-of-use drinking water dispenser might have an irradiation chamber volume of approximately 100 cm3, with a flow rate of 1.5 to 2 liters per minute, while a single-serving hot beverage dispenser such as a domestic coffee maker or infant formula dispenser might utilize an irradiation chamber having a flow rate between 0.3 and 0.4 liters per minute. A vending machine, commercial coffee maker, or other such unit that might be found in commercial service might require a larger irradiation chamber to accommodate a higher flow rate and/or pressure, and possibly to achieve a greater degree of irradiation in the liquid. One such embodiment may have an irradiation chamber around 600 cm3 and a flow rate of about 2 liters per minute.

[0078] Of course, it will be readily recognized that characteristics such as the size and shape of the irradiation chamber; the number, position, and intensity of the UV-LEDs; and the temperature, flow rate, and pressure of the liquid and coolant fluid must be adapted to the particular application in question. Many different, alternative embodiments can thus be conceived, of which two will now be discussed.

[0079] FIG. 2 is a section view of an apparatus 200 for purifying liquid according to a second embodiment.

[0080] The apparatus 200 is similar to the apparatus 100 depicted in and described with relation to FIG. 1, in that it comprises an irradiation chamber 202 and a coolant conduit 204, the latter being formed from the inner wall 216 and the outer wall 218. There are disposed upon the irradiation chamber 202 a plurality of UV-LEDs 212, which irradiate a flow 210 of liquid.

[0081] The flow 210 of liquid is first directed into the inlet 222. The inlet 222 feeds the coolant conduit 204, such that the flow 210 of liquid passes by the UV-LEDs 212, cooling them. The flow 210 then passes through the u-tube 240, which directs the flow 210 into the irradiation chamber 202. The flow 210 is then irradiated with UV radiation 214, and finally exits the apparatus 200 through the outlet 206.

[0082] In this way, the flow 210 serves as the coolant fluid even as it is, itself, irradiated. Such an arrangement is particularly advantageous where the flow 210 of liquid is provided in a chilled state, or where the flow 210 of liquid is cooled to the required temperature by means external to the apparatus 200. In either case, it is preferable that the flow 210 of liquid be at a temperature no greater than 10 Celsius. This ensures both the effective cooling of the UV-LEDs 212 and that the resulting liquid is at a temperature that is pleasant and refreshing to drink.

[0083] Moreover, the high specific heat of water means that, when employed as the coolant, its temperature will not rise more than a few degrees after being passed through the coolant conduit 204 and cooling the UV-LEDs 212.

[0084] FIG. 3 is a side view of an apparatus 300 for purifying liquid, according to a third embodiment. The apparatus 300 comprises, as in the two embodiments previously presented, an irradiation chamber 302 through which a flow 310 of liquid is conducted, and upon which the UV-LEDs 312 are disposed. As the flow 310 of liquid passes through the irradiation chamber 302, the UV-LEDs 312 irradiate it. As in the previous embodiments, there may be a thermally-conductive material in a space between the irradiation chamber and the coolant conduit 304, here omitted for clarity.

[0085] The apparatus 300 further comprises the coolant conduit 304. The coolant conduit 304 is in the form of a helical coil of tube having an axis coincident with the longitudinal axis 320 of the irradiation chamber 302. In this embodiment, the coolant conduit 304 constitutes the evaporator coil of a refrigeration system; as such, the inlet 322 receives a flow 326 of a refrigerant gas from an expansion valve, which passes through the coolant conduit 304 before exiting by the outlet 324 to a compressor of said refrigeration system. The refrigerant gas is preferably selected from R-134a, R-410a, or R-600, as these refrigerants are among the most commonly used for domestic and commercial refrigeration and their characteristics are well known.

[0086] Of course, the coolant conduit 304 does not necessarily constitute the whole of the evaporator; indeed, in it may be that the helical coolant conduit 304 only represents a portion of the evaporator, and that the remainder thereof is disposed elsewhere or employed to realize a different effect, e.g. maintaining the temperature of liquid that has already been purified.

[0087] The precise dimensional and operative characteristics of the refrigeration system will therefore depend on the particularities of the application in which it is used. The person of ordinary skill in the art will be capable of adapting characteristics such as evaporator coil size, shape, and composition; refrigerant type, pressure, and charge weight, and so on.

[0088] Thus, as the flow 326 of coolant evaporates in the coolant conduit 304, it will chill both the UV-LEDs and the flow 310 of liquid through the irradiation chamber. In certain embodiments, this may be employed to chill the flow 310 of liquid to the desired temperature for consumption.

[0089] 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.

[0090] In addition, 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.

[0091] Furthermore, it should be understood that the forms and configurations of the irradiation chamber and the coolant conduit as described in and with reference to the Figures are purely exemplary. In particular, it should be understood that a system employing a refrigerant gas as a coolant need not necessarily have its coolant conduit configured as a helical tube, nor must a system employing water as a coolant have its coolant conduit configured as a tube coaxial to the irradiation chamber.

[0092] Different forms or combinations of forms of the irradiation chamber and the coolant conduit may be employed, whether the coolant fluid is a refrigerant gas, water, or some other fluid substance. The configuration of the irradiation chamber and coolant conduit can thus be tailored for each application to realize optimal irradiation and cooling performance.

[0093] 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.

[0094] 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.