Ultraviolet light source
US RE22534 E
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Description (OCR text may contain errors)
Aug. Y1332, 1944.
W. O. PROUTY ULTRAVIOLET LIGHT SOURCE Original Filed March 23, 1 931 Reissued Aug. 22, 1944 ULTRAVIOLET LIGHT SOURCE Willis O. Prouty, Hermosa Beach, Calif., assignor,
by mesne assignments, to Westinghouse Electric and Manufacturing Company, New York, N. Y., a corporation util-Pennsylvania Original No. 2,093,735, dated September 21, 1937,
Serial No. 524,649, March 23, 1931.
Application for reissue February 18, 1939, Serial No. 257,172 f (el. 17e- 122) 11 Claims.
This invention relates to a source of ultraviolet light, such as can be used for therapeutic purposes.
This application is a continuation in part of my prior application, Serial No. 448,128, led
`April 28, 1930, and entitled Therapeutic light.
In the said prior application, I point out the disadvantages encountered in ultra-violet light sources utilizing mercury arcs or carbon arcs. These disadvantages, in brief, can be summarized as follows: Such devices require excessive energy consumption; they become so hot that artificial cooling is required;l and-due to such high temperatures,'it is dilicult to keep the tube sealed when tubes are used. Furthermore, the apparatus is bulky and costly. In mercury tubes, due to the high temperatures of operation, there is a pronounced absorption effect of the ultra-violet emanations, making the device inefficient.
These disadvantages canbe almost entirely avoided When a high-voltage discharge tube is used, having a filling of one or more of the noble monatomic gases. Such gases are now in common use, and include neon, argon, helium, and krypton. Discharge tubes having such a lling, stay cool and are compact.
Ordinarily neon or argon can be used as the gaseous lling, supplemented, although not necessarily, by the addition of a few drops of mercury to increase the ultra-violet radiations. I have found that the intensity of these emanations can be still further materially increased by proportioning the discharge tube in a manner thatwill be more specifically described hereinafter.
For example, in one series of comparative tests performed on a device incorporating my invention and a commercial mercury arc device, it was found that although the power consumed by my device was only about one-eighth that consurned by the mercury vapor device, yet my device emitted ultra-violet radiations in general much in excess of the mercury vapor device. The comparison was made at definite wave lengths of radiations; at wave lengths considerably above visibility, the intensities of the emanations from my device werevery much greater than from the other device. Since the therapeutic effect of such short wave lengths is especially beneficial, it is seen that this feature is of considerable importance.
Accordingly it is one of the objects of my invention to make it possible to secure this intense radiation of ultra-violet light by the aid of a luminous discharge device.
My invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of one embodiment of my invention. For this purpose I have shown a form in the drawing accompanying and forming part of the present specification. I shall now Proceed to describe this form in detail, which illustrates the general principles of my invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of my invention is best defined by the appended claims.
Referring to the drawing:
Fig. 1 is a side elevation of an ultra-violet ray device embodying my invention;
Fig. 2 is a longitudinal, sectional view thereof;
Fig. 3 is a detail section taken along plane 3`3 of Fig. 2;
Fig. 4 is a detail section taken along plane 4--4 of Fig. 2; and
Fig. 5 is a detail view taken in general in the direction of the arrow 5 in Fig. 2.
The source of ultra-violet radiations is shown as a tube II which is doubled one or more times on itself. This tube is shown as provided at its extremities with the small internal electrodes I2 and I3, but other forms of electrodes could be used if desired. This tube can be filled with any of the noble monatomic gases or mixtures thereof to a pressure of a few millimeters of mercury, say from four to twelve millimeters. A few drops of liquid mercury can also be inclosed inside the tube. This tube is made from material that can readily pass the ultra-violet rays, such as quartz. The tube II can, furthermore, be kept comparatively small, its doubled length in most instances not exceeding 10 or 12 inches, although the length of the tube II can be varied to suit conditions.
In order to obtain the best and most intense effects from the tube I I, its inner diameter should not exceed seven millimeters; the preferable value is about three or four millimeters. It should be` operated below a current consumption of 5() milliamperes, and a potential difference across it above 1G00 volts. Apparently the small diameter obviates material self-absorption ofthe rays, and the low current consumption, while suflicient to cause the gas to luminesce, yet serves to leave the tube I I cool enough to be readily handled by an operator without artificial cooling, inasmuch as its operating temperature is inherently below C. which is but slightly above body temperature, and which, as is well recognized from International Critical Tables, gives a mercury pressure of not more than 13 microns during operation of the device.
In order to house the tube II and provide terminals for connection to the electrodes I2 and I3 I may utilize a casing I4. This casing may be made from a casting such as aluminum. Its top portion may be generally cylindrical and is preferably formed with an. opening I5 through which the tube II can be exposed. In the present instance, the Width of the opening can be varied, as by a shutter IE which conforms K with the interior surface of the casing, and which can be manipulated as by a handle Il extending through a slot I8 in the back of the casing. If desired the interior surface of this shutter can be polished to act also as a reflector.
In order to permit the tube IMI to be inserted into the casing I4 there is provided a top opening I9. This opening can be closed by cover member 20. In order to steady the tube I I this cover member may carry a cushion or pad, such as 2|, 'made of sponge rubber or the like.
In theV present instancel the lower portion of frame I4 can be flattened, as indicated most clearly in Fig. 4. In this lower por-tion therev is a large opening 22" that can be covered up by' cover plate 23. This cover plate can be fastened in place by screws 2.4.
Terminal block 25 can be accommodated in: the: lower portionofv the casing and` can be held in place as by the aid of one or more screws 26., This terminal block can be made of' any appropriate insulation material. It carries a number of screws 2l, engaging theconductors 28, 29'that lead to the electrodesy I2 and I3. The extremities of the tube I I can be accommodated in shallow pockets, such as 30, 3l inthe front face of the block 25.
The conductorsk 28 and 29 can extend downwardly below block 25. They can pass through the neck 32 tothe exterior, andarefshown in Fig. 2 as carrying heavy insulation, forming the twin conductor 33.` A plug34 can be used to. maintainthis conductor 3.3 in placein the neck 32.
In order further to supportY the tube. I I against dislodgement I may utilize several turnsof asbestos rope 35 encompassing both bends of the tube II` near the lower portion thereof. Sponge rubber cushion 36 can be fastened to the cover 23 (Fig. 4) for holdingV these extremities in the pockets 30, 3|.
For the application of the ultra-violet rays to a comparatively large surface, the opening I5 can be used. The size of the opening can :be adjusted by manipulation of handle I'I, the hand of the manipulator grasping the lower portion of the-casing I4.
For more conned' treatment I can provide a tubular extension 39, at an angle to the casing axis, through which the upper part of the tube II can be exposed. If desired7 a supplementalv applicator coniining the area treated still further, can be supported in extension 39. One example of such applicators is indicated in Figs. 1, 2, and 5. It includes a quartz-rod 3l. This quartz rod is cemented in a metal collar 38, which is adapted to be disposed near the tube II. In order to support the collar 38 detachably in this projection 39, this extension can be provided with a bayonet slot 40 for accommodating pin 4I extending radially of. the collar 38.
In the present instance this applicator 3l is shown merely as a bent rod which is made of quartz, and which has the property of conducting they ultra-violet radiations from inside casing I4 to the extremity or tip 42 of the rod, without substantial dispersion transverse to the rod. The tip 42 of the applicator can therefore be directed against the locality to be treated.
I believe that the eiectiveness of this tube resultsA mainly from they small current consumption and small cross-sectional area. The small area ensures against interference and reabsorption or change of wave length, and the small cur- .rentrconsumptiom because it keeps the tube cool,
also contributes to the same end.
l. In a device for producing ultra-violet radiations having a high intensity in the wave band from 2000 to 2540 Angstrom units, a tube capable of passing such radiations, said tube having an internal diameter no greater than seven millimeters,` a filling for the tube of one or more noble monatomic gases, and means for impressing an energizing potential diierence across the column of gas-.in the tube.
2. In a device for producing ultra-violet radia tions having a high intensity in the Wave` band from. 2000 to 2540v Angstrom units, a tube capable off passing such radiations, said tube having an internal diameter no greater than seven millimeters a filling for the tube of one or more noble monatomicr gases, and means for impressing an energizing' potential dilerence across the column of'. gas inthe tube, to produce a current iiow therein not exceeding iifty milliamperes.
3. In a device for producing ultra-violet radiations having a high. intensity in the wave band from 2000 to 2540 Angstrom units, a tube capable of passing such radiations, said tube: having an internal diameter no greater than seven millimeters, a lling for the tube of one or more noble monatomic gases., and means for impressing an energizing potential differencefacross the column of gas* in the tube, said potential diierence being no less than one thousand volts.
4. In; a device for producing ultra-violet radiations having; a high intensity in the Wave band from 2000 to 2540 Angstrom units, a tube capable of passing such radiations, said tube having an internal diameter between three and four millimeters, a filling for the tube of one or more noble monatomic gases, and means forl impressing an energizing potential difference across the column of gasv in the tube, to produce a current flow therein not exceeding fifty milliamperes.
5. The process of producing ultra-Violet radiations having aV high intensity lying in the Wave bandV from 2000 to 2540 Angstrom units, by the aid of a luminous column of noble monatomic gases, which comprises energizing said gas column, and confining the column to a diameter no greater than seven millimeters.
6. The process of producing ultra-violet radiations having a high intensity lying in the wave band from 2000 to 2540 Angstrom units, by the aid of a luminousv column of noble monatomic gases, which comprises energizing said gas column, and reducing self-absorption in the column by restricting the diameter of the column.
7. The process of producing ultra-violet radiations having a high intensity lying in the wave band from 2000 to 2540 Angstrom units, by the aid of a luminous column of noble monatomic gases, which comprises energizing said gas column, confining the column to a diameter no greater than seven millimeters', and restricting the current flow through the column to a value not exceeding fifty milliamperes.
8. The process of producing ultra-violet radiations having a high intensity lying in the Wave band from 2000 to 2540 Angstrom units, by the aid of a luminous column of noble monatomic gases, which comprises energizing said gas column, and confining the column to a diameter -betWeen three and four millimeters.
9. An ultra-violet lamp for producing ultraviolet radiations having a high intensity in the wave band of 2000 to 2540 Angstrom units comprising an envelope containing a, gaseous lling at a pressure of at least 4 millimeters including mercury vapor and an inert gas, and means for impressing an energizing potential across said lamp to caus-e luminescence of said gaseous filling and to produce a current iiow therein sufficient to maintain the operating temperature of said lamp at approximately 50 C. whereby the mercury vapor is maintained at a pressure not greater than 13 microns.
10. The method of operating an ultra-violet lamp for producing ultra-violet radiations having a high intensity in the Wave band of 2000 to 2540 Angstrom units and provided with an envelope containing a gaseous filling including mercury vapor and an inert gas, which consists in impressing across the lamp an energizing potential suicient to cause luminescence of the gaseous filling, and restricting the current consumption of said lamp to a value such that the operating temperature ofthe lamp is maintained at approximately 50 C. and thus cool enough to be readily handled, and the mercury vapor pressure during operation is maintained at approximately 13 microns.
1l. A discharge lamp for producing ultra-violet radiations having a. high intensity in the Wave band of 2,000 to 2,540 Angstrom units comprising an envelope containing a gaseous filling includingmercury vapor and an inert gas, and means for impressing an energizing potential across said lamp to cause luminescence of said gaseous lling and to produce a current flow therein suiiicient to maintain the operating temperature of said lamp at approximately 50 C. and the mercury pressure at approximately 13 microns.
WILLIS O. PROUTY.