WO1998020365A1 - Ultraviolet light illumination and viewing system and method for fluorescent dye leak detection - Google Patents
Ultraviolet light illumination and viewing system and method for fluorescent dye leak detection Download PDFInfo
- Publication number
- WO1998020365A1 WO1998020365A1 PCT/US1997/019841 US9719841W WO9820365A1 WO 1998020365 A1 WO1998020365 A1 WO 1998020365A1 US 9719841 W US9719841 W US 9719841W WO 9820365 A1 WO9820365 A1 WO 9820365A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- light
- ultraviolet
- wavelengths
- filter
- fluorescing
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/64—Fluorescence; Phosphorescence
- G01N21/6447—Fluorescence; Phosphorescence by visual observation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/91—Investigating the presence of flaws or contamination using penetration of dyes, e.g. fluorescent ink
Definitions
- This invention concern liquid leak detection methods and more particularly leak detection using dyes which fluoresce when illuminated by light of particular wavelengths, typically ultraviolet light, commonly referred to as "black light”.
- Ultraviolet light sources are commonly employed for such uses as disinfection, prospecting, document examination, dental work curing, as well as leak detection.
- the fluorescing dye is typically mixed with lubricating oil which in turn is mixed with fluid in the equipment being inspected, such as in the refrigerant of an air conditioning system.
- the dye in the fluid leaked out will fluoresce when illuminated with ultraviolet light, so that the leaked fluid will be readily visible.
- Such dyes will fluoresce or emit light at certain visible band wavelengths, when excited by shorter wavelength ultraviolet light.
- a powerful light source emitting light at the proper wavelength should desirably be used, which source does not also emit visible light.
- This overheating can crack or shorten the lens, particularly if water drops impinge on the lens, the shattered glass presenting a hazard to the user.
- reflectors In attempting to create a more powerful light source, reflectors are commonly provided which concentrate and direct ultraviolet wavelength light emitted from a quartz envelope lamps. Prior art reflectors have typically been crudely formed and had low efficiency due to destruction interference set up by protective coatings such as silicon dioxide.
- a system comprised of an improved parabolic reflector and filter associated with an ultraviolet lamp, combined with viewing eyeglasses which filter certain visible wavelengths for achieving maximum contrast of the fluorescing light emitted from a dye exposed to the illumination by a leak.
- the improved reflector has an accurately formed parabolic shape. Two coatings of precisely control thickness applied to the reflecting surface and having substantially different refraction induces. These coatings minimize the interference of a reflected ultraviolet light beam with the incident light beam by inducing offsetting phase shifts such that the reflected light is closely in phase with the incident light.
- the ultraviolet light source is preferably a quartz envelop tungsten halogen lamp mounted at the focal point of the reflector parabola.
- the ultraviolet light beam from the reflection is then passed through an optical filter to selectively remove visible light from the reflected light beam by a process of selective reflectance rather than absorbance so as to minimize heat build up in the filter, as has occurred in previous light absorbing filters used for removing visible light.
- a series of coatings are applied to a borosilicate glass disc in order to achieve this.
- Successive coating layers of high and low refraction indices are used to produce selective reflectance of a wavelength band above the ultraviolet wavelengths but shorter than the infrared band, i.e., from 475 nm to 700 n .
- the infrared light is transmitted through the filter to reduce heating of the confined space behind the filter.
- the final element of the system is a pair of filtering viewing eyeglasses which absorb wavelengths just below the wavelength of the fluorescing light in order to block wavelengths of the illuminating light in this band, to increase the contrast and visibility of the fluorescence of the illuminated dye to the viewer' s eye.
- FIG. 1 is a diagram of the main components of the system according to the present invention.
- Figure 2 is an enlarged fragmentary section of the parabolic reflector component.
- DETAILED DESCRIPTION In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims.
- the system according to the present invention uses a portable ultraviolet light source not unlike a flashlight, which includes a parabolically shaped reflector 10 mounted in a housing 12, (a portion only shown in fragmentary form) which in turn mounts a lamp 12 located approximately at the focal point of the parabolic shape.
- the lamp 12 is preferably a Xenon lamp of high color temperature (>3500K) , which produces substantial long wave ultraviolet light emissions.
- the envelop is made of quartz which is itself highly transmittive to such long wave ultraviolet light.
- the lamp 14 is also relatively compact allowing it to be placed at the focal point of the reflector parabolic shape.
- a suitable bulb is available as part number FCR64625HLX from Osram Sylvania.
- the parabolic reflector is precision electroformed of nickel on an accurately shaped stainless steel mandrel.
- a focal point of 0.187 inches allows the lamp 14 to be approximately located at the focal point of the parabolic to maximize beam concentration.
- the lamp 14 is powered by a suitable power supply 16 which may consist of a transformer reducing 110 vac (or 220 vac) to 12 vac.
- a 12 volt dc power supply such as an auto battery may also be used.
- the lamp 12 draws 100 watts of power such that a high power source will be required, substantially greater than that required for a typical flashlight.
- a relay operated by a normally off spring biased switch (not shown) is used to turn the lamp 14 on and off, to minimize the on time of the lamp 14.
- the reflecting surface 18 of the parabolic reflector 12 has a double layer of coatings, which are designed to eliminate the destructive interference caused by refraction of the interface of each media through which the light passes in being reflected from the surface 18. Refraction of short wavelength ultraviolet light would normally cause a phase difference to develop between the incident and reflective light beam, setting up a destructive interference and reducing the intensity of the reflected ultraviolet light.
- the surface 18 is given coatings, one of aluminum and one of silicon dioxide. The interface of silicon dioxide and air, and silicon dioxide and aluminum produces a double refraction in an opposite sense, which offset each other to eliminate the potential destructive interference which would otherwise could occur.
- the first coating 18A is of aluminum, while the second coating
- 18B is of silicon dioxide (Figure 2) .
- the thickness of the silicon dioxide should be uniform and accurately held to achieve this effect, the thicknesses determined by the "quarter stack" principle.
- each interface i.e., the silicon dioxide and air, silicon dioxide and aluminum determines the effective phase shift of the reflected light.
- a thickness of aluminum of .057 microns and of silicon dioxide of .066 microns has been successfully used for this purpose.
- the silicon dioxide-air interface causes an approximate 13 degree forward phase shift, the silicon dioxide-aluminum interface a 13 degree lagging phase shift, thereby offsetting each other.
- Silicon dioxide coatings have heretofore been employed simply to protect the substrate from scratches and oxidation but have not been sufficiently uniform nor of the proper thickness to achieve enhanced reflection of ultraviolet wavelengths.
- a coated parabolic reflector suitable for this use is available from American Galvano, 312 N. Cota St., Unit 1, Corona, California 91720.
- a glass disc filter 20 is another component of the system of the present invention which is mounted to receive the ultraviolet beam emanating from the lamp 12 and the parabolic surface 18.
- the filter 20 is designed to reduce the visible light component of the ultraviolet light received from the lamp 12 and reflector 14.
- Such filters have been employed in the past but have typically been designed to absorb visible light to prevent its transmittance. This results in excessive heating of the lens when used with high intensity light sources, making it vulnerable to cracking or shattering, as when contacted with water drops due to rapid cooling of localized areas of the glass. According to the concept of the present invention, coatings are applied which cause reflection of the visible light ranges rather then absorbance, greatly reducing heating of the lens 20.
- the filter 20 itself is preferably of borosilicate glass, commercially available as "Pyrex" (TM) , which has a very low coefficient of thermal expansion to thus minimize cracking from thermal shock.
- TM borosilicate glass
- the fluorescing dyes typically used for leak detection have an excitation range of ultraviolet light of wavelengths 320 nm to 475 nm. When excited by such ultraviolet light, fluorescing light of 495 to 500 nm is emitted.
- Light over 700 nm is in the invisible infrared range, which is allowed to be transmitted out of the confined space through the filter 20 to avoid overheating particularly of the reflector 14.
- McCloud two layers of high and low refractive indices may be stacked to cause reflection of wavelengths only from 475 nm to 700 nm, allowing transmission of wavelengths from 320 nm to 475 nm and 700 nm to 1300 nm.
- the stack may be formed by the filter and a coating on the inside surface of the filter 20, which may be of titanium oxide.
- the glass and titanium oxide are of a thickness necessary to reflect the wavelength ranges described.
- coatings may be applied in various thicknesses, such as magnesium fluoride, which may also be applied to the other surface of the borosilicate to eliminate any residual transmitted visible lights.
- the general methodology is to create a bandwidth of reflected light above 475 nm extending approximately to 700 nm. The mean wavelength around which this bandwidth is centered would be 537.5 nm and a reflected bandwidth of 225 nm should therefore be employed.
- a suitable reflecting-transmitting filter lens for this purpose is available from:
- the system also involves the use of special viewing glasses 24 which are designed to absorb light wavelengths from 400 to 480 nm so that illuminating light from the source in those ranges reflecting from the inspected body 26 does not mask the emitted fluorescing light wavelengths which are in the 495 to 500 nm range emitted from the illuminated dye in the leaked liquid 28.
- Such narrow band blocking eyeglass lenses are available from:
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP97947315A EP0983522A1 (en) | 1996-11-05 | 1997-11-05 | Ultraviolet light illumination and viewing system and method for fluorescent dye leak detection |
AU52429/98A AU5242998A (en) | 1996-11-05 | 1997-11-05 | Ultraviolet light illumination and viewing system and method for fluorescent dye leak detection |
JP52160298A JP3434518B2 (en) | 1996-11-05 | 1997-11-05 | Ultraviolet irradiation and inspection system and fluorescent dye leak detection method |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US3009296P | 1996-11-05 | 1996-11-05 | |
US60/030,092 | 1996-11-05 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1998020365A1 true WO1998020365A1 (en) | 1998-05-14 |
Family
ID=21852453
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1997/019841 WO1998020365A1 (en) | 1996-11-05 | 1997-11-05 | Ultraviolet light illumination and viewing system and method for fluorescent dye leak detection |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0983522A1 (en) |
JP (1) | JP3434518B2 (en) |
AU (1) | AU5242998A (en) |
WO (1) | WO1998020365A1 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999053299A1 (en) * | 1998-04-13 | 1999-10-21 | Brasscorp Ltd. | Leak detector using fluorescent dyes |
EP1103805A2 (en) * | 1999-11-29 | 2001-05-30 | Marktec Corporation | Ultraviolet light permeable filter for flaw detection apparatus and method for detection of flaws |
US6362488B1 (en) * | 1997-11-05 | 2002-03-26 | Corrosion Consultants, Inc. | Light source and method for carrying out leak detection inspections |
JP2002542919A (en) * | 1999-04-23 | 2002-12-17 | アトランティウム エルティディ. | Liquid and gas sterilization and purification methods |
EP1367413A1 (en) * | 2002-05-27 | 2003-12-03 | Canon Kabushiki Kaisha | Reflector and linear illumination device |
EP1707611A2 (en) | 2000-09-08 | 2006-10-04 | Nanosolutions GmbH | Synthesis of nanoparticles |
US7241399B2 (en) | 2000-09-08 | 2007-07-10 | Centrum Fuer Angewandte Nanotechnologie (Can) Gmbh | Synthesis of nanoparticles |
CN104903745A (en) * | 2013-01-08 | 2015-09-09 | 斯基恩特-X公司 | X-ray scintillator containing a multi-layered coating |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6717325B2 (en) * | 2018-02-27 | 2020-07-01 | 三菱電機ビルテクノサービス株式会社 | Oil leak route identification method for passenger conveyor and oil leak route identification support system |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3107298A (en) * | 1960-11-09 | 1963-10-15 | James R Alburger | Apparatus for the measurement of fluorescent tracer sensitivity |
US3916205A (en) * | 1973-05-31 | 1975-10-28 | Block Engineering | Differential counting of leukocytes and other cells |
US4298005A (en) * | 1976-03-05 | 1981-11-03 | Mutzhas Maximilian F | Radiation apparatus |
US4990789A (en) * | 1988-05-10 | 1991-02-05 | Osamu Uesaki | Ultra violet rays generator by means of microwave excitation |
US5543137A (en) * | 1994-09-19 | 1996-08-06 | Repper; George R. | Method of protecting against sunburn |
US5592245A (en) * | 1994-08-10 | 1997-01-07 | Moore; J. Paul | Apparatus for enhancing visual perception of selected objects in recreational and sporting activities |
-
1997
- 1997-11-05 WO PCT/US1997/019841 patent/WO1998020365A1/en not_active Application Discontinuation
- 1997-11-05 AU AU52429/98A patent/AU5242998A/en not_active Abandoned
- 1997-11-05 EP EP97947315A patent/EP0983522A1/en not_active Withdrawn
- 1997-11-05 JP JP52160298A patent/JP3434518B2/en not_active Expired - Fee Related
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3107298A (en) * | 1960-11-09 | 1963-10-15 | James R Alburger | Apparatus for the measurement of fluorescent tracer sensitivity |
US3916205A (en) * | 1973-05-31 | 1975-10-28 | Block Engineering | Differential counting of leukocytes and other cells |
US4298005A (en) * | 1976-03-05 | 1981-11-03 | Mutzhas Maximilian F | Radiation apparatus |
US4990789A (en) * | 1988-05-10 | 1991-02-05 | Osamu Uesaki | Ultra violet rays generator by means of microwave excitation |
US5592245A (en) * | 1994-08-10 | 1997-01-07 | Moore; J. Paul | Apparatus for enhancing visual perception of selected objects in recreational and sporting activities |
US5543137A (en) * | 1994-09-19 | 1996-08-06 | Repper; George R. | Method of protecting against sunburn |
Non-Patent Citations (1)
Title |
---|
See also references of EP0983522A4 * |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6177678B1 (en) | 1995-04-05 | 2001-01-23 | Brasscorp Ltd. | Method and apparatus for leak detection and non-destructive testing |
US6362488B1 (en) * | 1997-11-05 | 2002-03-26 | Corrosion Consultants, Inc. | Light source and method for carrying out leak detection inspections |
WO1999053299A1 (en) * | 1998-04-13 | 1999-10-21 | Brasscorp Ltd. | Leak detector using fluorescent dyes |
USRE43332E1 (en) | 1999-04-23 | 2012-05-01 | Atlantium Technologies Ltd. | Method and device for disinfecting and purifying liquids and gasses |
JP2002542919A (en) * | 1999-04-23 | 2002-12-17 | アトランティウム エルティディ. | Liquid and gas sterilization and purification methods |
EP1103805A2 (en) * | 1999-11-29 | 2001-05-30 | Marktec Corporation | Ultraviolet light permeable filter for flaw detection apparatus and method for detection of flaws |
EP1103805A3 (en) * | 1999-11-29 | 2002-02-13 | Marktec Corporation | Ultraviolet light permeable filter for flaw detection apparatus and method for detection of flaws |
EP1707611A2 (en) | 2000-09-08 | 2006-10-04 | Nanosolutions GmbH | Synthesis of nanoparticles |
US7241399B2 (en) | 2000-09-08 | 2007-07-10 | Centrum Fuer Angewandte Nanotechnologie (Can) Gmbh | Synthesis of nanoparticles |
EP1367413A1 (en) * | 2002-05-27 | 2003-12-03 | Canon Kabushiki Kaisha | Reflector and linear illumination device |
US7336403B2 (en) | 2002-05-27 | 2008-02-26 | Canon Kabushiki Kaisha | Optical element and illumination apparatus having same |
CN104903745A (en) * | 2013-01-08 | 2015-09-09 | 斯基恩特-X公司 | X-ray scintillator containing a multi-layered coating |
EP2943808A4 (en) * | 2013-01-08 | 2016-08-03 | Scint X Ab | X-ray scintillator containing a multi-layered coating |
Also Published As
Publication number | Publication date |
---|---|
JP2001505122A (en) | 2001-04-17 |
JP3434518B2 (en) | 2003-08-11 |
AU5242998A (en) | 1998-05-29 |
EP0983522A4 (en) | 2000-03-08 |
EP0983522A1 (en) | 2000-03-08 |
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