US1826385A - Nonhardening vacuum tube lamp - Google Patents

Description

Oct 6,1931. 1.. L. BECK 1,826,385

NONHARDENING VACUUM TUBE LAMP Filed June 2 192 gvwentoz LEO L. BEC K ?atented @ct. 193i sates LEO L. BECK, OF LINDEN, NEW JERSEY, ASSIGNOR TO CLAUDE NEON LIGHTS, INC., OF

NEW YORK, N. Y., A CORPORATION OF NEW YORK NONHABDENING VACUUM TUBE LAMP Application filed June 2, 1926. Serial No. 113,147.

This invention relates to vacuum tube lights, and more particularly to lights in which a column of gas under low pressure, such as neon, is caused to glow by the passage of an electric current therethrough.

Lights of this type, as is well known, have a life that is limited, as at present constructed. After they have been in operation for a certain length of time, the voltage required to operate them increases to such an extent that the light is for all practical purposes inoperative. This process is termed in the art hardening and is known to be due to a lowering of the pressure of the gas within the tube.

While it might be supposed that this hardening is due to leakage of gas from the tube, it has been found that this is not the case. At least, the phenomenon is mainly due to causes other than leakage of gas from the tube.

It is an object of the invention to provide a method and apparatus for preventing, or at least materially delaying the hardening of vacuum tube lights such as neon lamps.

It is a further object of my invention to provide a vacuum tube light having an operating life greatly in excess of the operating life of known tubes of the class described.

It is a further object of this invention to provide a vacuum tube light having means introduced therein to prevent or materially delay the hardening of such lights in operation.

Still other objects of my invention will be apparent from the specification.

The features of novelty which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as touts underlying principles and as to its practlcal application, will best be understood by reference to the specification and accompanying drawings, in which Figure 1 represents a vacuum tube light in accordance with my invention; and Figures 2, 3, 4, 5 and 6 represent a method of introducing unheated glass chips which I prefer to use in practising my invention.

It has been found that this lowering of the gas pressure or' hardenin is not due to leakage of gas from the tufie but isdue to a totally different cause. It is generally believed that when a voltage is impressed between the electrodes of a vacuum tube light, such as a neon lamp of the type shown, electrons pass into the gas and travel toward the other electrode. During their passage, they cause the neon to glow and radiate its characteristic light. Some of these electrons. however, in passing from the electrodes to the gas, appear to carry off tiny particles of metal from the electrode, which particles are plljated out or deposited on the walls of the tu e.

It has been found that these metal particles, of perhaps atomic order of size, in their passage through the gaseous space of the tube, pick up or entrap molecules or particles of neon, and carry these gas particles with them. When the metal particles are plated out on the wall of the tube, the neon which they have entrapped no longer plays any art in the operation of the tube and eventua ly so much neon is entrapped and effectively removed that the gas pressure falls below that desired and the voltage required to cause illumination increases greatly. When this takes place, the practical operating life of the tube is at an en It is known that when an electric current is passed through a mixture of gases from metallic electrodes, the metal particles passing through the gaseous space entrap and carry off first the lightest gas of the mixture. and leave the heavier gases until the lighter are removed. For example, if hydrogen is admitted to a neon light, even in quantities small enough so that the operating characteristics of the tube are otherwise not affected, the metal particles will entrap and carry off the hydrogen as long as it is present, and the neon will be left.

I have found that this effect may be utilized to increase the length of useful operating 9 life of vacuum tube lights such as neon lamps, by arranging or providing for a slow evolution or introduction of hydrogen, or other substance having a similar effect, in the tube.

The result of this is that there will always 1 The Ttube 11 will be sealed to be hydrogen present in the tube and so long as it is present the neon or other active constituents will not be removed. During operation of the tube the hydrogen will be plated out, and by controlling the rate of evolution or introduction of the hydrogen in the tube in such a way thatit'is produced approximately as fast as it is removed, a balanced operating condition ,is achieved which results in a tubehaving an operating life greatly in excess of ordinarytubes.

The slow introduction or evolution of hydrogen necessary may be provided for in several ways, but I prefer to obtain it by introducing into the lamp envelope after exhaustion, some ordinary unheated glass, preferably in the form of chips, which may be distributed along the path of discharge between the electrodes of the lamp.

Referring now to the figure, 1 designates a tubular envelope of transparent material such as glass, having electrodes 2 disposed within the tubes, and supported on strings of glass beads 3 strung on wire, and connected to lead-in Wires 4 passing through a press 5. The space in the tube 1 is occupied by gas such as neon at relatively low pressure.

Unheated ordinary glass chips 6 are introduced into the. tube in any suitable way, but preferably in the way described and claimed in the copending application of Robert Smalley, entitled Method and apparatus for introducing foreign substances into vacuum tube lamps, etc. filed April 30, 1926, assigned to Claude Neon Lights, Inc. By unheated glass chips, I mean small particles or chi s which are substantially unheated during t e exhausting process.

Referring now to Figure 2, 11 designates a section of tubing preferably of glass having a second portion 12 sealed thereon to form a T. The lower end of the stem of the T is closed off as at 13 and the substance to be transferred to the interior of the lamp such as the unheated glass chips, is placed therein as indicated at 14. If desired, a neck portion 15 may be formed on the T on each side of the stem thereof, or at one side only if desired for convenience in sealing off and removing portions of the tube.

Referring now to Figure 3 I have shown diagrammatically a lamp envelope 1 in which it is desired to insert unheated glass chips 6.

the lamp envelope 1 as at 22 in such a manner as to establish contact between the interior of the T tube and the interior of the lamp envelope. The junction 22 between the T tube 11 and the lamp envelope 1 should be made air tight for a purpose which will be explained later. The opposite open end of the T tube 11 ma and preferably will be connected to tube 23 leading off to suitable pumps or other evacuating apparatus, not shown so that the lamp may be evacuated through tube 11, thereby 5 burner 25 to the any necessary heating of the lamp envelope may take place at'this time either with or without the passage ofcurrent through the lamp and either with or without supplemental heating of the electrodes to drive off occluded gases.

Since the material to be introduced is in the pocket 14 out of the path of current flow in the gas, the passage of current will not materially heat the substance to be intro duced into the lamp and thereby drive off the water vapor which it contains, this of course must be avoided.

After the tube has been properly evacuated, the evacuating apparatus may be dis- 1 connected, and the proper amount of desired gas, such for example as neon, introduced by opening a valve (not shown) in the evacuating line.

It is now evident that the tube has been evacuated and that it has been supplied with the proper amount of gas for operation. It should now be sealed 011' which may be done, for example by bringing a flame from a burner 25 to play upon the tube 11 between the junction of the T and the connection to the exhaust line.

The tube may now be aged and tested to make sure that it has the proper operating characteristics, before the introduction of the foreign substance. After the tube has been tested and found in good order the lamp envelope with the T tube attached thereto may be manipulated in a suitable manner to cause the foreign substance such as the glass chips 6 to flow down the stem of the T and down the top thereof as shown in Figure 5,. into the envelope 1 of the lamp proper. The simplest way of producing this result is simply to invert and tilt the lamp after which the T tube may be tapped gently to dislodge the glass chips.

The substance has now been introduced and the lamp will now have the desired operating characteristics. However, the T tube, or what remains of it protrudes from the envelope and might be accidentally fractured thereby ruining the lamp. Therefore I prefer to seal off and remove what is left of the T tube as shown in Figure 6 by bringing the junction point 22 of the T tube and the lamp and sealing off and removin the T tube as will be readily understood.

hile I do not wish to be bound by any explanation of the effect of the unheated glass chips, I believe that a slow and long continued evolution of water vapor takes place from the chips in the path of the discharge between the electrodes, and that this water vapor disassociates into hydrogen and oxygen. The hydrogen thus liberated is entrapped and removed by the metal particles, leaving the neon in its gaseous free state, and the rate of evolution of hydrogen is such that it is produced at about the same rate as it is removed. The quantity produced is dependent upon the quantity of glass chips introduced. Of course, it is to be understood that the chips must not be subjected to heating during the exhausting of the tube since that would remove the water vapor which they carry, nor is it necessary to wet them, as they carry suflicient water for the purpose even when they would ordinarily be considered dry.

I have found that unheated platinum produces the same effect, but is not so desirable because of its cost and because, being a conductor, it tends to short-circuit the discharge through the gas.

\Vhile I have described my invention and given what I believe to be the proper explanatigm for the actions which take place in the tu e, I am not limited thereby. I do know that the introduction of suitable foreign substances, such as unheated glass, unheated platinum, etc., has a marked effect in increasing the life of a vacuum tube li ht, such as a neon lamp, whatever the theoretical explanation may be, and I do not wish to be limited to any theory of action.

While I have shown and described certain preferred forms of my invention, it is clear that modifications and changes may be made without departing from the spirit and scope of my invention, as will be evident to those skilled in the art.

What I claim is:

1. A method of increasing the lift of neon positive column tube lamps comprisin a column of gas containing neon, energize by an electric current, which comprises sealing in contact with the gas in the lam envelope 8. foreign substance which will malntain a slow evolution of water vapor into the interior space of said lam 2. A method 0 increasing the lift of neon positive column tube lamps comprising a col umn of gas containing neon, energized by an electric current, whichcomprises sealing in contact with the gas in the lamp envelope a quantity of lass carrying water therewith.

3. A meth of increasing the life ofmeon positive column tube lamps comprisin a column of gas containing neon, energize by an electric current, which comprises scaling in contact with the gas in the lamp envelope a quantity of unheated glass. 7

4. A method of increasing the life of posi- I wish it distinctly understood that tive column tube lamps comp-rising a column of gas at relatively low pressure energized by electric current which comprises maintaining within the lamp envelope a relatively slow evolution of water vapor.

5. A method of increasing the life of positive column tube lamps comprising a column of gas comprising neon at relatively low pressure energized by electric current which comprises maintaining within the lamp envelope a relatively slow evolution of water vaor. p 6. A positive column tube lamp comprising a column of gas at relatively low pressure, adapted to be energized by an electric current and containing within the lamp env'elope a substance capable of maintaining a slow evolution of water Vapor within the envelope.

7. A vacuum tube lamp comprising a column of gas at relatively low pressure, adapted to be energized by an electric current and containing wlthin the lamp envelope a quantity of unheated glass capableof liberating water vapor at a relatively slow rate in said envelope.

8. A positive column tube lamp comprising a column of gas comprising neon at rela tively low pressure, adapted to be energized by an electric current and containing within the lamp envelope in the path of discharge a quantity of unheated glass.

In testlmony whereof I have hereunto set my hand this 21 day of 21%: 1926 L O L. BECK.

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