US 3296480 A
Description (OCR text may contain errors)
Jan. 3, 1967 A. WALZ GAS DISCHARGE LAMPS WITH SINUOUS DISCHARGE PATH BETWEEN ELECTRODES 3 Sheets-Sheet 1 Filed Nov. 19, 1963 BY Alfred U 41 W zzw/we 'T Jan. 3, 1967 WALZ GAS DISCHARGE LAMPS WITH SINUOUS DISCHARGE PATH BETWEEN ELECTRODES Filed NOV. 19, 1963 5 Sheets-Sheet 2 IN V EN TOR.
Jan. 3, 1967 GAS DISCHARGE LAMPS WITH SINUOUS DISCHARGE PATH BETWEEN ELECTRODES Filed Nov. 19, 1963 5 Sheets-Sheet 3 By ////re g/a/l United States Patent Claims priority, application Germany, Nov. 27, 1962,
W 33,421 4 Claims. (Cl. 313-404) The invention relates to a gas discharge lamp with a discharge vessel composed of two preferably axially symmetrical parts open towards one side in the direction of the axis of rotation, in which a helical discharge path following the axially symmetrical parts is provided, at the ends of which path the electrodes are arranged. Such a discharge vessel has a long discharge path as compared with its dimensions, which has a favorable effect on the degree of etficiency of the discharge lamp.
The object of the invention is to produce a discharge lamp with still longer discharge path and at the same time a particularly simple construction, thereby making it easier to manufacture. The invention is characterized in that the discharge vessel is composed of two substantially smooth walled wall parts enclosing a hollow space of annular cross-section in which a middle part with a helical depression on each side is arranged, which is so constructed and dimensioned that the protrusions bordering the depressions contact the side surfaces of the wall parts enclosing the hollow space along a helical line, a clearance being however left free between the edge at the end of the middle part having the largest diameter and the wall parts. The end of the middle part having the smallest diameter terminates in a tubular extension. The fluorescent layer is preferably applied on the middle part so as to obstruct the egress of the light as little as possible. In this case the ignition strip is preferably covered by the layer of fluorescent substance as otherwise a non-luminous strip would be produced.
Several embodiments of the invention are hereinafter described with reference to the accompanying drawings, in which:
FIG. 1 is a sectional diagrammatic view of the first form of construction, while FIGS. 2 and 3 are sectional diagrammatic views of other preferred forms of construction.
In FIG. 1, and 11 designate two axially symmetrical parts forming the outer boundary of the discharge vessel, the generatrix of which parts is substantially a straight line or a curve. In the end of the vessel having the smallest diameter, a socket 12 is inserted which has a tubular extension 13 in which one of the electrodes 14 is arranged. In the annular space between the wall parts 10 and 11 there is a middle part 15 provided with helical depressions dividing the discharge vessel into spaces 16 to 26. The middle part 15 is so constructed that the protrusions formed by the depressions contact the side surfaces of the wall parts 10 and 11 along a helical line so that the individual spaces 16 to 26 are sealed off from each other with the result that a helical discharge path is formed which extends from the electrode 14 to the electrode 27. The middle part 15 is so dimensioned that its edge 1512 at the end having the largest diameter does not touch the wall parts 10 and 11 so that here the discharge path can pass over from the inner side to the outer side of the middle part 15. When the discharge vessel is constructed in this manner it is possible to arrange both electrodes 14 and 27 of the lamp at the end carrying the socket 12, with the result that the construction of the lamp is simplified considerably because otherwise the lead to the electrode arranged at the other end of the lamp would have to run through the discharge space. This,
3,296,480 Patented Jan. 3, 1967 however, would present great difiiculties because the lead must be well insulated and only insulating material can be used which contains no imprisoned gases and does not decompose when subjected to ultraviolet radiation.
The middle part 15, when constructed according to the invention, is a component part of both sections 16 to 21 and 22 to 26 and, through being coated with fluorescent substance on both sides, is utilized twice. As a result, as compared with the conventional fluorescent tubes which are only internally coated with fluorescent substance, that is only on one side, the length and volume of the discharge path are greater with a given quantity of glass. Therefore the gas discharge lamp according to the invention has a great light intensity while being of smaller dimensions. The middle part 15 terminates at its end with smallest diameter in a tubular extension 15a which can be slipped on to the tubular extension 13 of the socket 112 with slight play. Thus a discharge path is produced which extends for example from the elect-rode 14 to the electrode 27 via the spaces 16 to 26. The electrode 27 is preferably connected to the socket 12 through the intermediary of a steadying resistance. This steadying resistance can be arranged inside the discharge vessel. In the example illustrated, it consists of an incandescent lamp 28.
The wall parts 10 and 11 can be made in a very simple manner in a single operation by blowing, as indicated by the dash lines in the drawing. The body produced is then parted along the line 29. The middle part 15 is made separately and placed in the part It the tubular extension 15a being slipped on to the tubular extension 13 of the socket. The fluorescent substance is preferably applied on the part 15. It serves at the same time for improving the seal between the protrusions of the middle part 15 and the wall parts 10 and 11 and between the tubular extensions 13 and 15a. To obtain a perfect seal between the parts 15 and 10, 11 as well as 13 and 15a, it is possible to use instead of or in addition to the fluorescent substance, a substance which is particularly stable in a vacuum and chemically resistant to UV. radiation. The part 15 may also carry an ignition strip which facilitates the lighting of the gas discharge lamp. The ignition strip is preferably applied before the fluorescent substance so that it does not cause any dark places on the middle part 15.
After the middle part 15 has been fitted, the part 11 shown in dash lines is inverted and also placed in the part 10. Thereupon the two wall parts 10 and 11 are welded together at the join 30 in known manner, or they can be cemented together with a suitable material such as Araldit.
The space exclosed by the wall parts 10 and 11 is then exhausted in the usual way and subsequently provided with a gas filling and a mercury additive.
As already mentioned, the fluorescent substance is preferably applied only on the middle part 15 and in a layer thickness yielding the maximum quantity of light which can be considerably greater than in the case of the standard lamps in which, as is known, the layer of fluorescent substance obstructs more or less considerably the passing out of the light. The two wall parts 10 and 11 are preferably free from fluorescent substance. They may, however, also be provided with a coat of fluorescent substance, in which case, however, this coat is kept very thin so as to obstruct the egress of light as little as possible.
FIG. 2 shows a modified form of construction in which spherically domed wall parts 40 and 41 are used which are better able to withstand external air pressure. 42 is the middle part, the helical depressions of which in combination with the wall parts 40 and 41 form spaces 43 to 51. The wall part 41 is first blown in one piece with the wall part 40 as shown in dash lines, and then parted along the line 56, turned upside down and welded to the wall part 40 in the manner described in connection with the first embodiment illustrated in FIG. 1. 52 and 53 are the electrodes. The tubular extension 42a of the middle part 42 is slipped on to the insertion 54. 55 is the screw socket.
The embodiment illustrated in FIG. 3 differs from that of FIG. 2 in that an intermediate or middle part 60 which is constructed as a rotary part, has on both sides substantially helical or spiral webs 60a and 60b which, when the lamp is assembled, bear against the smooth wall parts 40, 41 and thus produce the helical discharge passage 61 to 72.
The middle part 15 can "be made of electric conducting materials, e.g. of iron sheet, coated with a layer of glass or enamel insulating the conducting material from the discharge spaces. A middle pa-rt of such a construction is easy to produce and serves in an ideal manner as an ignition strip which facilitates the lighting of the gas discharge lamp.
What I claim is:
1. A gas discharge lamp comprising, in combination, two smooth-surfaced wall parts which are coaxial surfaces of revolution and define between them a sealed annular space whose diameter is substantially less at one axial end than at the other axial end; a middle part disposed within and along said annular space and having helical projections on both its radially inner surface and its rdially outer surface, each helical projection being in sealing contiguous relation with the smooth inner surface of the respective adjacent wall part; each projection forming, with the Wall part in contact therewith, one part of a discharge path, and corresponding axial ends of the two parts of the discharge path communicating with each other at the larger diameter end of said annular space; and a pair of electrodes each positioned at the other axial'end of a respective part of the discharge path.
References Cited by the Examiner UNITED STATES PATENTS Nisbet 313*20'4 1,602,245 10/ 1926 7 2,316,348 4/1943 Mahlet 313220 2,938,137 5/1960 Roger et al. 313- 197 2,985,787 5/1961 Scott 13-220 FOREIGN PATENTS 853,616 10/ 1952 Germany.
906,245 3/ 1954 Germany.
697,087 9/ 1953 Great Britain.
JAMES W. LAWRENCE, Primary Examiner. C. R. CAMPBELL, Assistant Examiner.