WO2019033205A1

WO2019033205A1 - Wavelength conversion device

Info

Publication number: WO2019033205A1
Application number: PCT/CA2018/050979
Authority: WO
Inventors: John GARNICA; Wes From; Michael Sasges
Original assignee: Trojan Technologies Group ULC
Current assignee: Trojan Technologies Group ULC
Priority date: 2017-08-17
Filing date: 2018-08-14
Publication date: 2019-02-21
Anticipated expiration: 2020-02-17

Abstract

A radiation source assembly is provided. The radiation source assembly includes (a) a radiation source element, and (b) a wavelength conversion element, wherein (a) and (b) are in spaced relation and reversibly engageable with respect to one another. A radiation source assembly is also provided that includes: (a) a radiation source element, and (b) a wavelength conversion element, wherein (a) and (b) are in spaced relation and configured to be disengageable with respect to one another.

Description

WAVELENGTH CONVERSION DEVICE

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims the benefit under U.S.C. § 119(e) of provisional patent application S.N. 62/546,839, filed August 17, 2017, the contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0002] In one of its aspects, the present invention relates to a radiation source assembly. In another of its aspects the present invention relates to a radiation source module comprising a plurality of the subject radiation source assembly. In yet another of its aspects, the present invention relates to a fluid treatment system comprising the one or more of the subject radiation source assembly disposed in the radiation source module or directly immersed in fluid being treated.

DESCRIPTION OF THE PRIOR ART

[0003] Compounds that absorb short-wavelength photons and emit longer-wavelength photons are well known.

[0004] They are generally called "phosphors" because many contain the element phosphorous. Such phosphors are commonly used to convert the short wavelength UV emissions from a mercury vapor lamp to longer wavelengths, such as UVA or UVB for tanning, or to visible wavelengths for general lighting applications.

[0005] Generally, there are two types of "phosphor" lamps.

[0006] First, with the phosphor coated on the inside of the mercury vapor lamp - e.g., conventional fluorescent lamps used in general lighting. The phosphors, coated on the inside of the lamp wall, convert the short wavelength mercury vapor emissions to longer wavelength visible light.

[0007] Second, with a second outer sleeve surrounding the mercury vapor lamp, in which this second sleeve is coated on the inside with phosphor, and the whole is integrated into an assembly - see Figure 1 which is Figure 10 from EP 0,010, 991A2 (Thorton et al.)

[0008] United States patent 6,447,537 (Hartman) describes a phototherapy device that converts UV radiation of a first wavelength to a different wavelength in therapeutic UVA or UVB range. The phosphor source is completely separate and placed away from the UV source. In addition a radiation directing assembly with an exit aperture is required - see Figure 2 which is Figure 1 from Hartman.

[0009] United States Patent Application Publication No. US2012/0119119 [Soltesz-Nagy] describes a UV-converter for transforming radiation of wavelengths above 200 nm to UVA and UVB radiation, having at least a light transmitting sheet, with a luminescent coating on one side of the sheet, characterized in that the light transmitting sheet is made of a material filtering out UVC radiation, the luminescent coating provided on the surface of the light transmitting sheet is isolated from moisture of the environment and the luminescent material is selected from those producing a UV spectrum specified for solarium lamps - see Figure 3 which is Figure 1 from Soltesz-Nagy.

[0010] In type 1, the phosphor is exposed to the plasma ions and bombardment with mercury ions, resulting in short lifetime. In type 2 the phosphor is protected from direct bombardment, but is still integrated with the plasma lamp. Both must be discarded together, even though the plasma lamp may still have good output long after the phosphor coating has degraded.

[0011] In a typical lamp for tanning, emitting at about 365nm, the useful lifetime of the phosphor coating is only about 2000 hours. By contrast the mercury emission source inside this lamp has a useful lifetime of 12,000 hours or more. As a result of phosphor degradation, the entire radiation source assembly must be discarded after only 2000h, greatly increasing operating cost. [0012] Thus, despite the state of the art exemplified above, there is room for improvement. Specifically, it would be desirable to have a radiation source assembly in which a faster wearing portion (e.g., the phosphor containing element) could be replaced without the need to replace at the same time a longer wearing element (e.g., the radiation source).

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals denote like parts, and in which:

Figure 1 illustrates Figure 10 from EP 0,010, 991A2 (Thornton et al.), showing a phosphor layer 64 on a protective envelope separate from the arc discharge lamp 66.

Figure 2 illustrates Figures 1 and 2 from United States patent 6,447,587 (Hartman), depicting the UV source (10), the exit aperture (14), and the handpiece 16 containing the phosphor element (20).

Figure 3 illustrates Figure 1 from US20120119119 (Soltesz-Nagy), depicting the conversion of UVC to UVA and UVB through a light transmitting sheet with a luminescent coating (13).

Figure 4 illustrates an embodiment of the invention, illustrating an elongate radiation source disposed coaxially within a single walled sleeve having coated thereon a phosphor layer (dark black line).

Figure 5 illustrates an example of reversible engagement of sleeve (containing wavelength conversion element) and radiation source.

DISCLOSURE OF THE INVENTION

[0014] It is an object of the present invention to obviate or mitigate at least one of the above- mentioned disadvantages of the prior art.

[0015] It is another object of the present invention to provide a novel radiation source assembly. [0016] Accordingly, in one of its aspects, the present invention provides a radiation source assembly comprising: (a) a radiation source element, and (b) a wavelength conversion element, wherein (a) and (b) are in spaced relation and reversibly engageable with respect to one another.

[0017] In another of its aspects, the present invention provides a radiation source assembly comprising: (a) a radiation source element, and (b) a wavelength conversion element, wherein (a) and (b) are in spaced relation and configured to be disengageable with respect to one another.

[0018] The inventive concept separates the short wavelength emitter (e.g., a UV radiation source such as a mercury arc plasma lamp) from the wavelength conversion element (e.g., phosphor) so that each can be replaced according to its own functional lifetime. This allows the inexpensive wavelength conversion element to be replaced more frequently than the more expensive emitter, which has longer lifetime. In a preferred embodiment, the phosphor may still be surrounding the full circumference of the lamp and may be used in the treatment of fluids with UV radiation.

[0019] In a preferred embodiment, the phosphor is coated on a quartz or inexpensive soft-glass sleeve that is physically separate from the short-wavelength emitter - e.g., mercury arc lamp. The two are not fused or glued together, and may be replaced separately. Rather they are reversibly engageable with respect to one another. This results in a radiation source assembly in which a faster wearing portion (e.g., the phosphor containing element) may be replaced without the need to replace at the same time a longer wearing element (e.g., the radiation source).

[0020] In a fluid (e.g,. water) treatment reactor, the wavelength conversion element (e.g., phosphor) element may also be the water barrier, or it may be an intermediate element between the short-wavelenght emitter (e.g., a UV radiation source such as a mercury arc plasma lamp) and the fluid (e.g., water) barrier sleeve.

[0021] The wavelength conversion element (e.g., phosphor) may be designed in at least one of two ways:

[0022] First, the wavelength conversion element may be a radiation transparent sleeve with phosphor coated on the inside or outside. This may also include a protective coating, such as may be applied by chemical vapor deposition or other process - for example, see Figure 4. [0023] Second, the wavelength conversion element may be a double-walled sleeve, in which the phosphor is sealed between the two walls of the double-walled sleeve. This protects the phosphor from humidity, oxygen and other contaminants or detrimental compounds extending phosphor lifetime but at increased cost. This may be accomplished by a process in which two sleeves are sealed together on their ends creating an encapsulated volume and the wavelength conversion element (e.g., phosphor compound) may be disposed the outside of the inner wall and/or the inside of the outer wall. Figure 5 shows an example of this.

[0024] In a preferred embodiment, the short wavelength is about 254nm and the longer wavelength is about 365nm (i.e., after conversion).

[0025] In a preferred embodiment the present invention relates to a wavelength conversion device that absorbs radiation at a first wavelength and emits at a second wavelength, where the device is comprised of one or more transparent sleeves where the inner or outer surface of one or more sleeves is coated with a phosphor-based compound.

[0026] The present radiation source assembly is believed to be useful to treat most fluids, particularly liquid fluids. This includes water, aqueous liquids and hydrocarbon liquids such as oil.

[0027] Soybean oil treatment requires thousands of lamps emitting at 365nm. It is belived that the present invention may be able to drastically reduce the Operating and Maintenance costs by extending phosphor lifetime and allowing replacement of the wavelength conversion element without replacing the lamp. This could reduce costs by 50%.

[0028] Other embodiments will be apparent to those of skill in the art having in hand the present specification.

[0029] While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments. [0030] All publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.

Claims

What is claimed is:

1. A radiation source assembly comprising: (a) a radiation source element, and (b) a wavelength conversion element, wherein (a) and (b) are in spaced relation and reversibly engageable with respect to one another.

2. A radiation source assembly comprising: (a) a radiation source element, and (b) a wavelength conversion element, wherein (a) and (b) are in spaced relation and configured to be disengageable with respect to one another.

3. The radiation source assembly defined in any one of Claims 1-2, wherein the radiation source element comprises an elongate low- wavelength radiation source element.

4. The radiation source assembly defined in any one of Claims 1-2, wherein the radiation source element comprises an elongate UV radiation source element.

5. The radiation source assembly defined in any one of Claims 1-2, wherein the radiation source element comprises an elongate mercury arc lamp.

6. The radiation source assembly defined in any one of Claims 1-5, wherein the wavelength conversion element is disposed on a radiation transparent element.

7. The radiation source assembly defined in Claim 6, wherein the radiation transparent element comprises a sleeve element.

8. The radiation source assembly defined in Claim 6, wherein the radiation transparent element comprises a quartz sleeve element or a soft-glass sleeve element.

9. The radiation source assembly defined in any one of Claims 7-8, wherein the sleeve element comprises a closed end and an open end.

10. The radiation source assembly defined in any one of Claims 7-9, wherein the wavelength conversion element is disposed on an interior surface of the sleeve element.

11. The radiation source assembly defined in any one of Claims 7-9, wherein the wavelength conversion element is disposed on an exterior surface of the sleeve element.

12. The radiation source assembly defined in any one of Claims 7-9, wherein the wavelength conversion element is disposed on an interior surface and an exterior surface of the sleeve element.

13. The radiation source assembly defined in any one of Claims 7-12, wherein the wavelength conversion element is disposed on an entire radial surface of the sleeve element.

14. The radiation source assembly defined in any one of Claims 7-12, wherein the wavelength conversion element is disposed on a partial radial surface of the sleeve element.

15. The radiation source assembly defined in any one of Claims 7-12, wherein the sleeve element comprises a double-walled construction comprising a first inner wall and a second outer wall combining to define a chamber therebetween.

16. The radiation source assembly defined in any one of Claims 7-12, wherein the sleeve element comprises a double-walled construction comprising a first inner wall and a second outer wall combining to define a hermetically sealed chamber therebetween.

17. The radiation source assembly defined in any one of Claims 15-16, wherein the wavelength conversion element is disposed in the chamber.

18. The radiation source assembly defined in any one of Claims 15-17, wherein the wavelength conversion element is disposed on a surface of the first inner wall of the chamber.

19. The radiation source assembly defined in any one of Claims 15-17, wherein the wavelength conversion element is disposed on an entire radial surface of the first inner wall of the chamber.

20. The radiation source assembly defined in any one of Claims 15-17, wherein the wavelength conversion element is disposed on a partial radial surface of the first inner wall of the chamber.

21. The radiation source assembly defined in any one of Claims 15-20, wherein the wavelength conversion element is disposed on an entire radial surface of the second outer wall of the chamber.

22. The radiation source assembly defined in any one of Claims 15-17 wherein the wavelength conversion element is disposed on a partial radial surface of the second outer wall of the chamber.

23. The radiation source assembly defined in any one of Claims 1-22, wherein the radiation source element and the wavelength conversion element are combined with a mechanical coupling.

24. The radiation source assembly defined in Claim 23, wherein the mechanical coupling comprises a threaded coupling.

25. The radiation source assembly defined in Claim 23, wherein the mechanical coupling comprises a friction fit coupling.

26. The radiation source assembly defined in Claim 23, wherein the mechanical coupling comprises a ratchet coupling.

27. The radiation source assembly defined in any one of Claims 1-26, wherein the wavelength conversion element comprises an optical filter.

28. The radiation source assembly defined in any one of Claims 1-26, wherein the wavelength conversion element comprises a dichroic mirror.

29. The radiation source assembly defined in any one of Claims 1-26, wherein the wavelength conversion element comprises a phosphor layer.

30. The radiation source assembly defined in any one of Claims 1-26, wherein the wavelength conversion element comprises a material which converts UVC radiation to UVB radiation or a material which converts radiation at a wavelength of 254nm to radiation at a wavelength of 364nm.

31. The radiation source assembly defined in any one of Claims 1-26, wherein the wavelength conversion element comprises a gadolinium doped matrix.

32. The radiation source assembly defined in Claim 31, wherein the matrix comprises a member selected from the consisting of yittria, a borate, a silicates, a ternary aluminate activated by a cation selected from the group consisting of Bi, Pb, Sr and Ca, and any mixture of two or more of these.

33. The radiation source assembly defined in any one of Claims 1-26, wherein the wavelength conversion element comprises an alkali halide matrix doped with one or both of Ag and Tl.

34. The radiation source assembly defined in any one of Claims 1-26, wherein the wavelength conversion element comprises (Ca,Zn)3(P0₄)2:Tl.

35. A radiation source module comprising a plurality of the radiation source assembly defined in any one of Claims 1-34.

36. A fluid treatment system comprising a fluid treatment zone for receiving a flow of fluid and one or more radiation source modules defined in Claim 35 configured such that one ore more radiation source assemblies is/are disposed in the fluid treatment zone.

37. A fluid treatment system comprising a fluid treatment zone for receiving a flow of fluid and one or more of the radiation source assembly defined in any one of Claims 1-34.

38. The fluid treatment system defined in any one of Claims 36-37, where in the fluid is a liquid.

39. The fluid treatment system defined in any one of Claims 36-37, where in the fluid is an aqueous liquid.

40. The fluid treatment system defined in any one of Claims 36-37, where in the fluid is a hydrocarbon liquid.

41. The fluid treatment system defined in any one of Claims 36-37, where in the fluid is an oil.