US2279818A - Method of making seals - Google Patents

Description

A ril 14, 1942. e. A. FREEMAN METHOD OF MAKING SEALS Filed July 15, 1939 INVENTOR 62/). BY W ATTORNEY Patented Apr. 14, 1942 UNITED STATES PATENTdQFI-I CE I I METHOIS SEALS I t v George A. Freeman, East Orange, N. 1.,

assignor to Westinghouse Electric Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application my 15, 1939, Serial No. 284,575

' a cum. (01.49-81) electrode that will be accurately positioned through the container of a quartz lamp.

Another object is to provide an electrode that lends itself to easy sealing by machine, particularly where a starting electrode is employed.

- Another object of my invention is to accurately space a startingelectrode from the adjacent main electrode in a quartz lamp.

A still further object of my inventionis to provide a method of sealing a double seal through quartz lamps that does not require a special skilled technique by the operator.

Other objects and advantages of the invention will be apparent from the following description and drawing in which:

Fig. l is a cross-sectional view through a quartz lamp embodying the invention.

Figs. 2 and 3 are elevational views of the 4 conductors and their glass beads.

Fig. 4 is a side view and Fig. 5 an end view of a special chuck that 1 have developed for holding the conductors.

Figs. 6 and 7 are elevational views of the conductors in the chuck of Fig. 4.

Figs. 8 and 9 are elevational views of steps in the process of sealing the conductors in one end of a quartz container.

Fig. 10 is an elevational view of a modification of the double seal in Fig. 7.

The method of making a quartz lamp generally involves a highly specialized technique on the part of the artisan. The conductors are sealed individually by hand into the various parts of the quartz container. The glass from that in contact with the conductor to the quartz that is the major portion of the container, is generally graduated in its percentage of quartz. The result of this individual hand sealing/of the electrodes in the quartz lamp brings about a variation between the various lamps so constructed.

In case a starting electrode is utilized, the individual sealing-in of the main electrode and then the starting electrode makes a,further variation and lack of uniformity between the various lamps. Furthermore, the sealing-in of a main electrode and then a starting electrode in one end of the quartz lamp involves a highly specialized technique. I J

It is an object of my invention to simplify the method of making double seals on quartz lamps, and especially to provide amlethod whereby the accurate spacing of the main electrode from the starting electrode will be secured without the exercise ofhighly speciallized technique.

In Fig. 1 I have illustrated a quartz lamp that is utilized for brilliant and efficient illumina tion. This quartz lamp has a container II with a main electrode Ii, sealed in, one end and anis sealed an elongated cylindrical bead II of glass, known as flux glass. This glass preferably contains approximately to quartz. One glass I have found especially suitable contains approximately 83% quartz (810:). 13% boric oxide and 4% aluminum oxide.

A similar bead i6 of flux glass is sealed around the conductor of the starting electrode II. In Fig. 4 I have illustrated a special chuck which I have devised for the purpose of accurately spacing the main electrode and the starting electrode from each other. This chuck comprises a-main body 18 with a central hollow portion l9, shown in dotted lines, and a set screw 20 extendingtherein for the purpose of securing it to any desired support. The front part of the chuck 'is conical at 2| and then expands slightly into a truncated portion 22. A hole 22 is drilled from d the front face 24 so that it is slightly exposed at the portion 25 of the conical face 2!. A spring 26 is secured to the side of the chuck and is bent downward to engage the exposed portion of the hole 23. A slot 21 is cut on the other side of the chuck and this slot has its trough accurately spaced at 28 from the opening 23 the distance that is desired to space the starting electrode from the main electrode. A spring 28 is secured to the side of the chuck and exerts a pressure towards the trough of the .slot 21.

One of the conductors ll with its "bead I5, is inserted in the opening 23 as illustrated in Fig. 6, and the other conductor I1 is placed in the trough 21 under the resilient pressure of the spring 29, as likewise illustrated in Fig. 6. The two beads l5 and I6 space these conductors further apart than the desired distance. As can be seen in Fig. 6, the reason for thisis that the overall radius of each head is larger than half the desired distance between the two conductors in Fig. 7. A gas flame or other heating means is then applied to the glass beads I! and- It.

The chuck, conductors and beads are preferably revolved and the two beads are melted together in the unified glass mass ll, around the tube conductors ll and II. when the glass of the two beads becomes plastic, the pressure exerted by the spring 20 against the conductor II.

will move this conductor towards the conductor ll until the conductor l1 'rests in the trough of the slot 21 and is stopped by this trough at the lead-in, placing the two bead units adjacent each other, exerting lateral pressure on a bead unit in the direction of the other bead unit, melt- .ing said beads into-a joint bead and sealing the joint bead in a quartz container.

2. The method' of sealing two conductors through a glass bead which comprises melting a glass bead on each of said conductors, securing one of said conductors in position, pressing the other conductor and bead laterally so that the two beads are in contact, and directing heat on the beads until they are united. I

3'. The method of sealing two conductors through a glass bead which comprises melting a glass bead on each of said conductors, securing one of said conductors in position, placing is preferably the same glass as for beads pre-- viously described. The glass from the quartz cylinder to the conductors may be two or more kinds to bridge the difference in expansion between the quartz cylinder and the conductors instead of being just an intermediate glass. A

' central opening 38; is left at this end of the quartz container. 7

In Fig. 9 I have disclosed the assemblage of a main electrode, starting electrode and unified I glass head held in a convenient chuck or other means I! and the glass container 34 brought towards it with its opening 38 positioned at the intermediate sidev of the unified. glass bead 30. The flame 36 provides the means I for sealing the quartz container to the intermediate side of the bead 30. An inert gaseous atmosphere is preferably applied to the interior of the container 34. The single mainelectrode II can be sealed in the opposite end.

Throughout the description of Figs. 2 through 9 I have disclosed an elongated bead on the conducting wires. These elongated beads are suitable for substantially 15 mil wire. In case it is desired to utilize larger diameter wire such as 30 mil wire, the elongated cylindrical head is not desirable. With this larger wire, I prefer to coat only an elongated film 40, illustrated in Fig. 10, on these wires and have a round bead II at an intermediate portion of this film of glass.-

Fig. 10 illustrates a main electrode 42 and starting electrode 43 having the fihns' II and M thereon, and having round beads 4| and 45 sealed into a unified mass 46 by the apparatus and method illustrated in Figs. 6 and '7, with the elongated cylindrical beads.

Although I have shown and described a speciflc embodiment of my invention, I-do not desire to be limited thereto, as various other modifications of the same-may. be made without departing from the spiritv and scope of the appended claims.

I claim:

1. The method of sealing an electrode-and starting electrode in a quartz tube which comprises melting a bead on the electrode lead-in,

said second conductor and bead adjacent said first conductor and bead with the beads in contact, exerting lateral pressure against said sec- .ond conductor towards said first conductor, limiting the minimum spacing between said conductors under said pressure, melting said beads to permit the second conductor to move to the said minimum spacing and letting the beads cool into a unified mass.

4. The method of sealing the conductors of an electrode and starting electrode in a quartz tube qwhich comprises melting a glass bead on each of said conductors, securing one of said conductors in position, placing said second conductor and bead adjacent said first conductor and bead with thebeads in contact, exerting lateral pressure against said second conductor towards said first conductor, limiting the minimum spacing between said conductors ,under said pressure, melting said beads to permit the second conductor to move to the said minimum spacing and letting the beads cool into a unified mass, and

sealing the unified mass in a quartz container.

5. The method of sealing and spacing two conductors in a glass bead which comprises melting on each of said conductors a glass bead having portions with a radius larger than half the desired distance between the two conductors, placing said portions in contact, melting'the portions into an integral bead and exerting lateral pressure on one of saidconductors until it occupies the desired position in the melted integral bead, and cooling the bead. '6. The method of sealing and spacing two conductors in a glass bead which comprises melting on each of said conductors a glass bead havsaid beads and with the second of said conducmelting another bead on the starting electrode tors movable toward the fixed conductor as the beads soften, exerting pressure on said movable conductor toward the fixed conductor, melting the beads until the pressure moves the second conductor laterally toward the fixed con-

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