US2088545A

US2088545A - Electric discharge lamp

Info

Publication number: US2088545A
Application number: US628040A
Authority: US
Inventors: Chester H Braselton
Original assignee: NAT TELEVISION CORP
Current assignee: NAT TELEVISION CORP; NATIONAL TELEVISION Corp
Priority date: 1932-08-09
Filing date: 1932-08-09
Publication date: 1937-07-27
Anticipated expiration: 1954-07-27

Description

Jul 27, 1937.

c. H. BRASELTON ELEC'ITRIQ DISCHARGE LAMP Filed Aug. 9, 1932 INVENTOR Patented July 27 1937 ELECTRIC DISCHARGE LALIP Chester H.=Braselton, New York, N. Y., assignor to National Television Corporation, Wilmington, Del., a corporation of Delaware 7 Application August 9, 1932, Serial No. 628,040

4 Claims. "(01. 176122) v Still another object of the invention is to provide a discharge lamp in which a high degree 15 of ionization is maintained in the gas.

Another object is to provide a long life discharge lamp.

Other objects of the invention and objects relating to the construction and assembly of the 20 various parts will be apparent as the description of the invention proceeds. Several embodiments of the invention have been illustrated in the accompanying drawing in which:

25 Fig. 1 is a perspective view partly in section of one form of my improved lamp;

Fig. 2 is a sectional elevational view of a modified form of lamp;

Fig. ,3 is a sectional elevational view of still 30 another modification of the invention; and

Figs. 4, 5, 6, and 7 are perspective views of still other forms of electrodes.

Referring now more specifically to the drawing, the construction shown in Fig. 1 which may 35 be the preferred form of the invention, comprises an envelope I formed of glass, quartz, or other suitable transparent material, similar in shape to an ordinary electriclight bulb and provided at its lower end with an inturned press H which 4 is fused to the wall of the envelope. In order to fulfill the objects of the invention, I desire toprovide the electrodes with as large amount of active surface as possible, and I have found that 45 this is accomplished very readily by making them about 60 wires to the inch each way, the wires being about .007 of an inch in diameter. The

material of the electrodes may be any metal 5 which can be easily freed from occluded gases and which is a good conductor of electricity. Such material may be molybdenum, iron, nickel, Monel metal, tantalum, tungsten, and many other metals -including even copper It may be desirable, how- 55 ever, to use a metal having a low contact potenout of a fine wire mesh, for instance, one having tial for the particular gas with which it is to beused.

In this form of the invention I use two electrodes l2 and I3 formed of sheets of wire mesh which are bent in the form of a semi-cylinder. 5 The electrode I3 is bent around a slightly smaller radius thanthe electrode l2 so that the edges l4 thereof may flt Just inside of the'edges ii of the electrode I2 but without coming in contact there with. The electrode I! may be reinforced by a semi-circular wire ii at the top thereof which may be welded to the wire mesh and a second semi-circular wire, i I at the lower edge which may also be welded to the electrode. A support rod I8 may be sealed in the press II and may be welded to both the wires Ii and H to rigidly support the electrode in position. In like manner the electrode It may have a semi-circular wire i9 welded to the inner surface of the upper edge while a wire also bent in the i'orm of a semicircle maybe welded to the inner surface of the lower edge. A support rod 2| also sealed in the press ll may be welded to the wire mesh at the top and bottom edges to rigidly support the electrode in spaced relation to the electrode l2.

Leadin wires

22 and 23 may be connected respectively to the support rods I8 and 2| for connecting the lamp in a circuit.

With the electrodes mounted in position and the envelope fused to the press as indicated in Fig. 1, the bulb may be connected 'to an exhaust pump and the temperature of the glass and electrodes raised by placing an oven over the lamp to thoroughly exhaust the envelope and remove 'all' occluded gases from the electrodes. After the Where intensity of illumination is not nec es'- 5 sary as for an exit light or night light, the bulb may be filled with neon gas which, as is well known, produces a reddish discharge when a current is passed through. it.

The large surface provided'by each wire mesh I electrode, which exceeds the surface of a solid electrode of the same dimensions, greatlyincreases the conductivity between the gas andthe electrode and permits the electrode to co 1 readfly, as the gas may circulate throughthus eliminating danger of the formation of overheated spots which might cause localized discharge and possible arcing between the electrodes.

In a lamp of this nature it appears to be desirable to provide the cathode with a greater surface than the anode, but where the lamp is adapted to be used with alternating current, one electrode acts as a cathode during one cycle of the current while the other one acts as a cathode for the other cycle. It is therefore desirable as shown in Fig. 1 to have both electrodes with an equally large surface. However, where the lamp is intended to be used with direct current, it may be desirable to provide the anode with a smaller surface and the construction of Fig. 2 may be used. In this figure the envelope 24 may be provided with a press 25 similar to the envelope and press already described, while the cathode 26 may take the part of a hollow cylinder of wire mesh which may be welded or otherwise supported upon two support rods 21 and 28, one of which, 28, may have a lead-in wire 29 connected to it. Both of the support rods 21 and 28 are sealed in the press 25. The anode 30 may comprise a single rod which may be sealed in the center of the press 25 and may extend upwardly 'through the center of the cylinder 26 terminating about even with the upper edge thereof. The rod 38 may have alead-in wire 3| connected to it. In such construction it will be evident that the negative side of the circuit should be connected to the Iea'd-inwire 29 while the positive side should be connected to the lead-in wire 3|.

Another embodiment of the invention is illustrated in Fig. 3 where the electrode 32 comprises a hollow cylinder of wire mesh similar to the electrode 26 described above and supported upon support rods 33 which are sealed in a press 34 fused to the envelope 35. The other electrode may also comprise a cylinder 36 of smaller diame ter and mounted concentrically of the cylinder 32 upon a support rod 31 which also is sealed in the press 34. Lead-in

wires

38 and 39 may be connected respectively to one of the support rods 33 and the support rod 31 to make the necessary connection to the lamp. While the surface of the inner electrode 36 is not as great as that of the outer electrode due to its smaller diameter, it nevertheless is very much larger than the single rod 38 of Fig. 2, and the lamp may be found to give good service on alternating current although direct current may give better results.

In Fig. 4 another form of the invention is illustrated wherein the electrodes 48 and 4| are formed of flat squares of wire mesh. A U-shaped rod 42 may be welded to the electrode 43 to reinforce the two side edges and the bottom there of in a manner clearly indicated, while a second U-shape rod 43 may be welded in a similar manner to-theelectrode 4| to reinforce its side and bottom edges. A pair of support rods 44 and 45 may be sealed in the press 46 and welded respectively to the rods.42 and .43, holding the rods and the electrodes in spaced relation to each other as clearly indicated. With this construction the spacing between the electrodes is uniform and the potential drop through the gas between any two opposite points will be the same.

A The above modifications of the invention have all been described and illustrated as having wire -mesh electrodes because of their maximum surface and minimum mass, as well as theiradaptability' for ready cooling,-but other means of increasing the surface of the electrode may be resorted to. In Fig. 5, for instance, a pair of electrodes 41 and 48 have-been shown mounted on'support rods 49 and 50 respectively, these rods being sealed in a press 5|. The electrodes 41 and 48 are formed of metal plates 52 which are perforated with a large number of holes 53 which should have a diameter less than twice the thickness of the plates in order to increase the surface thereof. In Fig. 6 a single electrode 54 is shown mounted upon a support rod 55, and this electrode consists of a plate 56 the surface of which is etched so as to make it irregular and thus increase the surface.

Fig. 7 shows a still further modification of the invention in which the single electrode 51, shown supported upon a support rod 58, is corrugated, crinkled, or otherwise deformed to crowd a large surface of the plate' into a small area. Other means for increasing the surface of the electrode may be used such as by making them of standard metal or by wrapping wire around a solid electrode, but none of these appear to give as good results as the wire mesh which reduces the mass to a minimum and increases the surface to a maximum:

It will be seen from the above that I have provided a discharge lamp in which the electrodes may be maintained relatively cool thus preventing arcing or localized discharge and in which the .velope and having concave sides opposed to each other, one of said electrodes being formed with a smaller radius than the other and having its side edges positioned within the side edges of the other electrode.

2. An electric lamp comprising an envelope, a gas within said envelope, a pair of wire mesh electrodes mounted within said envelope in spaced apart relation, said electrodes being semi-cylindrical in form with one slightly smaller than theother in diameter, and said electrodes being positioned with their concave faces opposed to each other and with the smaller electrode slightly within the larger one.

3. An electric discharge lamp comprising anenvelope, an ionizable gas within said envelope, and a pair of spaced apart semi-cylindrical electrodes within said envelope, said electrodes being positioned to form a hollow body having adjacent side edges, the radius of one electrode being less than that of the other, there being only two electrodes within the envelope. I

4. An electric lamp comprising an envelope, an ionizablegas within said envelope, a pair of wire mesh electrodes mounted within said envelope in spaced apart relation, said electrodes being curved on an axis substantially parallel to theaxis of the lamp and the radius of curvature of one of said electrodes being less than that of the other.

CHESTER H. BRASELTON.