US2514753A - Glow discharge device - Google Patents

Description

July 11, 1950 .J. FREEMAN 2,514,753

GLOW DISCHARGE DEVICE Filed Aug. 7. 1946 Patented 1 1 1950 v 2,514,75 1 repress s. DEVICE dispensed with entirely, and the interruption of current through two. or more. discharge tubes, and

hence theirilluminationis achieved Solely by. the construction andoperation of the tubes them-.: selves.-.: My methodiis thus much cheaper and more reliable, and eliminates much costly 1 equip"- ment and expensive repair It. is .welllknownain :the art, that if a pas or high pressure metal vapor; dischargertubes or a pair 'ofllowwpressurefigas discharge tubes of the neon gas type are connected in parallel across a high voltage circuit, only one of thepair of tubes will light up and the other will remain inoperative. This has been supposed to be due; to the fact that the characteristics of such tubes are such that notwo tubes have exactlyythe same resistance and when a discharge starts in one of the tubes, the supply voltage then is not sufficient tofstart thedischarge in the other'tube. It'also is .well known that the voltage required to start thedisc'hargeof such tubeswhen'lcold'i's much less thanpwhe'n' hot and'fifj, the lighted tube is extinguished, due to temporary 1 failure of the siinpiyvonag'e; it wn1-notrestaruat the, normal supply" voltage until" cooled;

I have made the very surprising discovery that p by connecting in parallel two or more low pressure glow discharge tubes of the neon gas type having an inside diameter much less than is commercially desirable, thetubes will light up and be extinguished repeatedly in rapid sequence provided all the tubes have the same capacity, that is, the same diameter, length and gas pressure. In accordance with my present preferred practice, I employ tubes having an inside diameter of 4 to 6mm. and, preferably, about 5 mm., but tubes may be used having an inside diameter of from length of the tube is not particularly important except that all should be the same length. It is not commercially practical to employ tubes less than 6 inches in length.

, rationofhMassachusetts about 2 mm. up to not more than 8 mm. The Y Ja'cob Freeman,- Boston, Mass, assignor to J.

Freeman lncorporated, Boston, Mass, at corpo- ApplicationAugust 7, 1946', Serial No. 688,905

' "some (01.315450) in other re'spects,;the tubes may be constructed inacco'rdance with the conventional practice of the art; Thus, any gascommonly employed in uch] low pressure tubes may be used, such as neonyargon, helium, mercury vapor, etc., or mix-- tures thereof. *However, I prefer to use the nonmetallic gases since the results are superior in many respects. The preferredgas pressure is betweenz mmrand 20 mm. of mercury.

' lqha've discovered also that a unit of a plurality of low pressure glow discharge tubes of small inside diameter connected in parallel, as previously described, may be utilized to cause a pin rality of glow discharge tubes of largeinside diameter to light-up and be extinguished repeatedlydn rapidsequence. Thus, I may cause the'glow discharge tubes'of commercial signsfand other display devices to light up and be extin guished repeatedly in rapid sequence. To accomplish this, the actuator unit must contain the same number of glow discharge tubes as the display device and each of the latter tubes should be"connected separately in series with a corresponding-tube of the actuator unit. Furthermore, each of the glow discharge tubes of the displaydevice should havethe same capacity, that isithe "same length, diameter and gas pressure. The glow discharge devicesof the display device may be low pressureglow discharge tubes of the necjsngas yl e containing neon, argon, helium, 8110., gases or mercury vapor or mixtures thereof orthey may be high pressure metal-vapor discharge devices.

- The: invention will be more clearly understood from the "following description in conjunction withih'e accompanying drawing in which:

fFig-Z 1"i's"a diagrammatic view illustrating one device embodying the invention; and

Fig. 2 is a diagrammatic view illustrating another device embodying the invention.

Fig. 1 illustrates one specific device embodying the invention and comprises a plurality of glow discharge tubes l0, each having a length of four feet, an outside diameter of 6 mm., and an inside diameter of approximately 4 mm. They are provided at their opposite ends with electrodes II and I2 of Swedish iron and contain neon gas at a pressure of 4 mm. of mercury. Each of the tubes ID are connected in parallel across the leads I5 and I6 which are connected to the secondary winding I! of a standard commercial sign lighting transformer having the primary winding [8. The transformer was rated at 7500 volts and 18 milli-amperes.

When ower was supplied to the transformer,

the tubes I were caused to light up and be extinguished in random sequence repeatedly, each tube being lighted up and extinguished at the rate of approximately 60 to 100 times per minute. Apparently with such tubes connected in parallel, the tube charge is built up in the tube lighted first to such a value that its starting voltage is higher than that of another tube, and another tube will be lighted in place of the first. The tube charge in the second tube then builds up, and in the previously lighted tube falls off. When more than two similar tubes are thus connected in parallel, they will light up in sequence, but not necessarily in any regular order, and thusprg llqe.

In the device illustrated in Fig. 2, the unit, A

comprises a plurality of glow discharge tubes liyhaving the same specifications as the tubes Hi of Fig. l. The tubes Ill are connected in parallel across the leads l5 and I6" which are eonnected to the secondary winding [1' of a standard commercial sign lighting transformer having the primary winding l8. The transformer was rated at 7500 volts and 18 milli-. amperes, Thedisplay H device D comprises a plurality of glow discharge tubes 20 having the us a e e r des 2! and 1.2 and a e c e te n ser s, w h h. f, th tubes Ashl trated, the electrode ll! of each of the tubes lll' is connected to the lead l5 by a lead 23 and each of the electrodes I I connected to the adjacent electrode 2-2 of the corresponding tube 20' by a lead 24. The other electrode 2| of each of the tubes go is connected bya lead 25 to the lead 16', When power was supplied the transformer, each tube I0 and the device 20- connected in. series with it was caused to light up and be ex; tinguished together and the devices 20 were caused to light up and be extinguished in randq n sequence repeatedly in substantially the same manner as in the device shown in Fig. 1.

It will be understood that the devices 20 may b f any type m nl mpl ye n mm r al or i y. d e t 1. m. l tters r other characters, symbols, etc. Thus, the de-. vice Zlimay be high-pressure metal vapor dis-.. charge devices, but, in any case, all of the devices 20 should be of the same capacity, that is, the same length, same, diameter and same gas, pres--. sure. The actuating unit A may be positionedat any place remote from the display devieel), and if, compactness is desired, the low-pressure glow discharge tubes l0! may be short, for example, about two feet in length, but, for practical reasons, their length should be greater than 5,1}; inches.

It will also be understood that the capacity of the transformer employed is determined by the capacity of the tubes Ill and the devices 20, as will be readily understood by those skilled in the art.

I claim:

1. In combination, a plurality of similar low pressure glow dischargetubesof the neon gas type. each having the. same diameter, same length and same gas pressure, means for electrically connecting said tubes in parallel, each of said tubes. having an inside diameter between about 2 mm. and 8 mm. whereby when said means. is connected to a source of electrical energy suitable .to cause any of said tubes to light up they will light up and be extinguished repeatedly in rapid sequence, and another glow discharge tube having an inside diameter greater than 8 mm. electrically connected in series with each of said low pressure tubes, each of the tubes of largest diameter having the same length, same gas pressure and same diameter. whereby each will light. up and be extinguished with the low pressure tube with which itis connected in series. 2. In combination a. plurality of similar low pressure glow discharge tubes of the neon gas. type each having the same. diameter, same length and samegas pressure, means for electrically connecting said tubes in parallel, each of said tubes having an inside diameter between 4 and- 6 mm. whereby when said means is connected to a source of electrical'energy suitable,

to cause any of said tubes to light up they will light up. and be extinguishedrepeatedly in rapid sequence, and another glow discharge tube hav.- ing an inside diameter greater than 8 mm. electrically connected in serie with each of said low,

pressure tubes, each of the tubes of largest. diameterhaving the same length, same gas pres-. sure and same diameter whereby each will light. up and be extinguished with the low pressure tubewith whichit connected in series.

JACOB FREEMAN.

REFERENCES GLETED.

The following references are of record in the file of; this patent:-

UNITED STATES PATENTS

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