US2172635A

US2172635A - Luminous tube lighting system

Info

Publication number: US2172635A
Authority: US
Publication date: 1939-09-12
Anticipated expiration: 1956-09-12

Description

Sept. 12, 1939. c. H. BECHTER 2,172,635

I LUHINOUS TUBE LIGHTING SYSTEM Filed March 6, 1937 mvwm v 24 Low Power 5 Fad-or Load mm; 23

Consi'an'l- I v Consi'ani' C n'l' Tran rmer 6 I \NVENTOR Charles H. Bechi'el BY ATTORNEY Patented Sept. 12,- =1939 I UNITED STATES PATENT OFFICE 2,172,635 LUMINOUS TUBE LIGHTING SYSTEM Charles H. Bechter, Los Angeles, Califl, assignor to Flame Lite Corporation, Los Angeles, Calif., a. corporation or California Application March 6, 1937, Serial No. 129,455

10 Claims. (01.176-124) This invention relates to a system for energiztube column although leaving irregular intering luminous tubes, such as neon tubes now stices. Such material need not be dielectric, so in common use for display purposes. long as they do not form short circuiting bridges;

Tubes of this character have been made in but one material may be a series of crumpled the past; they usually have a filling of one or thin mica sheets, inserted within the tube.

more of the noble monatomic gases, such as It is accordingly still another object of this neon, argon, helium, krypton, etc. The filling invention to provide a tube structure that inusually has a pressure of about to 15. millieludes crumpled sheets of thin material for enmeters of mercury, and a high ionizing potential hancing the unstablecharacter of the discharge.

10 difference is impressed upon the electrode ter- Instead of providing a separate element for the no minals at the ends of the tube. .The period of parallel load to the tube, it'is feasible so to conuseful life of such tubes is extended. This long struct the transformer that the secondary overall life is due to the use of a considerable amount of oad thereon has t e req s e low power factor, gas in the tube, evidenced by the gas pressure as by providing leakage in the-magnetic circuit.

5 of 10 to millimeters of mercury, as well asdue It is accordingly another object of this invention ill! to the use of large electrode areas in relation to to provide a transformer adapted to operate a the current flow, which may be of the order of tube of the character defined, in an unstable 50 milliamperes. manner. I

The most practical source of energy for sup-' This inherent instability, in conjunction with plying tubes of this prior character is a constant the large current flow in the tube, causes a very w current transformer. The tubes, although in striking appearance, not unlike that of a flame .reality reversing the current flow many times of intense brilliance within the tube.

in each second through them (in accordance with This invention po ses es many other advanthe alternations of the electromotive force imtages, and has other objects which may be made a pressed across them), appear nevertheless to more easily apparent from a consideration of burn with a steady brilliance. several embodiments of the invention. For this It has been proposed in the past to enhance purpose there are shown a few forms in the the effect of the tube by causing it to flicker in an drawing accompanying and forming part of the irregular manner, such as by causing the position present specification. These forms will now be of the luminous positive column of gas to alter described in detail, illustrating the general prinw in an erratic manner; and especially by causing ciples of the invention; but it is to be understood the discharge to be unstable. In all such' prior that this detailed description is not'to be taken attempts, the overall luminosity of the tube is n a limiting sense, since the scope 1 the invenrather poor; this is due at least partially to the ion s best defin by the a p Claimsfact that such prior tubes must utilize a gas pres- Referr ng to the drawin sure much below the usual values'of about 10 to Figure 1 is a ag of a system incorporating 15 millimeters of mercury pressure, and somet v n times as low as a few millimeters of mercury. Figsand 4 are d a a s S a to 1 It is one of the objects 'of this invention to of modified forms of the invention; and

40 make it possible to operate luminous tubes at Fig. 5 is an enlar ed sectional V ew Of a 11- intense brilliance and in an unstable manner, minous tube utilized in connection with the invenand yet secure an extended tube life. tion. Y 1

In order to secure these results, it has been The luminous tube l is shown of indefinite found, as one of the essential requirements, to ength and its Configuration y conform W parallel the tube with a load that, in conjunction any desired-design, such as letters or borders of 45 with the tube, forms a low power factor load for signs. The luminous tube is preferably made the source of electrical energy, such as the secof transparent t a such s glass y ondary of a transformer. This reduction in glass, provided with

electrodes

2 and 3 at the power factor may be optionally a capacitive or ends thereof, whereby the electrical energy may 5 an inductive load; ordinarily it is more convenbe conducted to the tube l. so lent to utilize an inductiverather than a ca- Preferably the filling of the tube comprises one pacitive load. *or more of the noble monatomic gases, such as Another requirement is that the tube space neon, argon, helium, etc., although slight adfor the gaseous content be irregular, as by placmixtures of other gases or vapors may be used, ing within the tube, materials that interrupt the such as mercury.

In ordinary tubes of this character the size may vary from as little as 6 millimeters external diameter to as high as or millimeters external diameter; and the gas pressure within the tube is ordinarily from 10 to 12 millimeters of mercury. The quantity of gases thus present in the tube I is considerable and the life of the tube is therefore enhanced even upon a large current flow of the order of 120 milliamperes or more.

By the aid of the present invention, an unstable discharge is secured through the tube and of considerable biilliancy, producing a flame-like effect. In order to secure this result, it is first of all essential toprovide a tortuous path for the discharge in the tube I. This is preferably accomplished by inserting within tube I pieces of crumpled up thin sheets of mica, such as illustrated by reference character 4 in Fig. 5. Other materials, dielectric or conducting, might be used,

so long as they do not form continuous circuits within the tube. The reflecting quality of the mica sheets 4 together with the tortuous path thus provided for the luminous positive column enhance the brilliancy of the discharge. This efiect of brilliancy is still more marked by the irregular and unstable flame-like pathof the discharge around and about the crumpled obstructions.

It is the main purpose of this invention to secure this instability even when the tube is brilliantly lighted by a current flow 'of 120 milliamperes or greater. For this purpose it has been discovered that the instability of the discharge can be easily secured by paralleling the tube I with a supplemental load 5 so as to make the combination of tube I and load 5 have a power factor in the neighborhood of 20 to 30 per cent. This low power factor load 5 may be either capacitive or inductive. Apparently due to this parallel connection and the continual cyclic lighting and extinguishing of the tube I by supplying alternating current to the

electrodes

2 and 3, the discharge incessantly flickers from one tortuous path to the other throughout the length of the ube.

In the form shown in Fig. 1 the source of electrical energy is indicated as a constant current transformer. 6, the primary of which. may be \shunted by a condenser I, suflicient to correct the power factor on the primary side of the trans former 6.

It has been found that the low power factor load 5 and the energizing transformer 6 may readily be combined in one structure. Such a form is illustrated in Fig. 2. In this case the energizing transformer is fed from the mains 8. The source is provided with a laminated iron core 9 upon which are wound the primary and secondary windings. The primary winding in this instance is shown. as comprising the three sections III, II and I2 in series and on separate portions of the core 9. The secondary winding comprises three corresponding sections I3, I4 and I5 placed in this instance in parallel and across the luminous tube I. In order to provide the low power factor shunting load, the core 9 is provided with magnetic'. leak paths between the sections so as to increase the .leakageflux between the primary and'ls'econdary. for example poles I6 and may-extendfrom the main body or the core swarms narrow air gap intermediate the sections'm -and 13.; Similar poles I8 and Is are {provided for the sections II and I4 and poles 2! and 2I-f orljthe secti ;I2 and I5.

The effect of the leakage paths thus provided is to increase the stray inductance in the transformer to such an extent as to reduce the power factor of the load supplied by the secondary side of the transformer to the desired low value. It has been found that by appropriate choice of air gaps the power factor can be reduced to the requisite value of 20 to 30 per cent.

In the form, of the invention illustrated in Fig. 3 the parallel load is shown as formed by a pair of

coils

22 and 23 having an iron core 24. The coil 22 isconnected across the terminals of the tube I and in order to increase the inductance of this parallel load the coil 23 may be connected to an appropriate source of alternating current.

In still another form of the invention illustrated in Fig. 4, the secondary winding 25 of the iron cored transformer 26 may be connected across the terminals of the tube I. The primary winding 21 may be connected to a source of alternating current. In this case the low power factor is secured by the aid of a magnetic shunt 28 between the winding 25 and 21. On this shunt 28 may be wound a short circuited coil 29 to increase the inductive reactance.

In all of the forms disclosed, the important characteristic is the supplying of the luminous tube I from a source, and so loading the source in parallel with the tube, as to produce a low power factor; and further, in the provision of a tortuous path for the discharge within the tube I. When these factors are present, the tube I may be illuminated very intensely with a relatively high current flow of 50 milliamperes or greater. There is a rapid intense unstable, discharge which persists over long periods of use. The instability is not destroyed by the use of the comparatively high gaseous pressure mentioned, such as 10 or 12 millimeters of mercury.

What is claimed is:

1. A luminous discharge tube, having material therein to give a tortuous path for the discharge, means for energizing the tube, and a load paralleling the tube to reduce the power factor of the combination of the tube and the load to a value no greater than thirty percent.

2. A luminous tube having a gaseous filling. and thin sheets of crumpled material within, the tube.

3. A luminous tube having a gaseous filling of a pressure neighboring ten millimeters of mercury, and thin sheets of crumpled material within the tube.-

4. A luminous tube; thin sheets of crumpled discharge, as well as, a' noble monatomic gaseous filling of a pressure neighboring ten millimeters of mercury means for energizing the. tube, and aload paralleling the tube to reduce the power factor of the combination of the tube and the,

energizing said tube, said energizing means hav- 'ing provisions for'paralleling the tube load with a load so that the combined parallel loads have a power factor no greater than thirty percent.

7. 'A luminous discharge tube having material therein to provide a tortuous path for the discharge, and a transformer for energizing said tube, said transformer having a primary and a secondary winding, as well as, an iron core, said windings and the core being so arranged that the total load on the secondary winding, including the tube, has a power factor no greater than thirty percent. a

8. A luminous discharge tube in which there is a noble monatomic gaseous filling at a pressure of no less than ten millimeters of mercury, and having material therein to provide a tortuous path for the discharge, and a transformer for energizing said tube, said transformer having a primary and a secondary winding, as well as an iron core, said windings and the core being so arranged that the total load on the secondary y no greater than thirty percent.

9. A luminous discharge tube having crumpled mica sheets therein to provide a tortuous path for the discharge, and a transformer for energizing said tube, said transformer having a primary and a secondary winding, as well as an iron core, said windings and the core being so arranged that the total load on the secondary winding, including the tube, has a power factor no greater than thirty percent.

10. A luminous tube, means for energizing the tube, and a load fed by the energizing means and paralleling the tube to reduce the power factor of the combination of the tube and the load, said load comprising a pair of coils and an iron core for the coils, one of said coils shunting the tube, and the other coil being energized by an alternating current.

CHARLES H. BECH'I'ER.