US690952A - Incandescent electrode vapor electric lamp. - Google Patents

Description

lllivrrnn *rares arent retient1 PETER COOPER HEWITT, OE NEV YORK, N. Y., ASSIGNOR TO PETER COOPER I-IEWITT, TRUSTEE, OF NEW YORK, N. Y.

INCANDESCENT ELECTRODE VAPOR ELECTRlC LAMP'.

SPECIFIGATIGN forming part of Letters Patent No. 690,952, dated January 14, 1902 Application led April 18, 1900. Serial No: 13,290. (No model.)

To @ZZ whom it nt/tty concern:

Be it known that I, PETER COOPER HEWITT, a citizen of the United States, and a resident of New York, in the county of New York and State of Nev7 York,have invented certain new and useful Improvements in Incandescent Electrode VaporElectric Lamps, of which the following is-a specification.

My invention relates to that class of electric-lighting devices in which electric energy is transformed intolightbyits action upon gases or vapors inclosed in a suitable chamber with a suitable lightemitting electrode. In the operation of lamps of the character referred to I have found that suitable gases having the proper density may be so aiected by electric currents of moderate electromotive 'force as to yield light and cause the negative electrode to be heated to a high degree of incandescence. A large portion of the resistance which a lamp of this character offers to the passage of current is at the joint of the gas with the cathode where the current enters the cathode, the gas also presenting considerable resist-ance. By suitably adjusting these resistances the resistalice at the cathode may be made such that the cathode Will itself become heated to a high degree of incandescence, being itself near the center ofthe source of heat and emitting intense light. The relative amount of light developed in the vapor-path is small on account of the relatively short path of the current through the vapor and a certain portion of this vapor-path is occupied by the dark space which surrounds the negative electrode.

In operating lamps with currents of considerable quantity the electric current tends to pass around to the back of the cathode and unless prevented is liable to fuse the leading in conductors and disintegrate the glass through which they pass. To prevent this, I provide a protecting-covering for such portions of the electrode, leaving exposed only those portions at which it is desired that. the current shall enter.

In the accompanying drawings, Figure l illustrates one form of lamp, and Figs. 2 and 3 a modilication.

Referring tothe drawings, l represents the main body of the lamp.

2 represents an electrodein this instance the anode-located in the lower part of the lamp, and the cathode is represented at 5. The electrodes may be made of suitable material-such, for instance, as iron or other conducting material-but I may make the cathode of some light-etnissive material, such as rare earths or mixtures thereof, surrounding' the conductor leading the current toit. The nature of the material of the cathode makes but little difference with respect to its conductivity, as even When it is of a material which is a non-conductor when cold. there is suflicient electric leakage into the lainp from the conductor leading into it (unless great care be take to prevent it) to start the current, which when started will heat the material by reason of its position at the negative electrode. The electrode 2 is shown as being seated Within a glass column l0, Which surrounds the leading-in Wire '7; but-the position of the positive electrode for this style of lamp may be varied. The electrode 5 is shown as being seated Within a tube I4, of porcelain or other suitable material which is a non-conduc tor and retains this quality when hot and is inert to electrical and chemicalv actions at the temperature to which it is subjected in the operation of the lamp. The cylinder 14 is shown as being carried by the stent or column I2 of glass through which the leading-in Wire 8 passes. The joints between the electrode and the porcelain and between the porcelain and the glass are sufliciently tight to prevent the electric current from passing through them and reaching the metal parts within, thus forming an electrically-tight insulation over the conductor vleading through `the walls of the vessel to the electrode.

With electrodes of the characterdescribed I am able to operate the lamp so that the current Will pass to and from the electrodes and be prevented from passing around to the por Vtions near the leadingin conductors.

The lamp illustrated in Fig. l is so construct-ed and its elements are so arranged that in the normal operation of the lamp the cathode Will be heated to a very high tempera ture, becoming itself a light-emitting body'. In this instance the electrode 5 is located at the center of a globe l5, the anode 2 being carried in an extension lli'. Gas of the proper density is placed Within the globe. When the current traverses the lamp, considerable IOO heat is generated at the cathode 5, and the surrounding gas being, in a measure, at least, a non-conductor of heat the temperature of the cathode 5 is maintained sufficiently high to be light-emissive. I have found, for instance, that with attenuated nitrogen contained within the chamber and with iron electrodes separated a distance of about one and one-half inches the lamp may be started with a direct current having a pressure of seven hundred and fifty volts or less, and the resistance which the gas oers to the passage of the current and the resistance Which is offered between the gas and the cathode will render the lamp self-governing and pass a definite amount of electrical energy and convert it into light vand heat, the heat being sufficient to maintain the cathode in a state of incandescence. It has been found that the resist-- ance of a vapor varies inversely with the cnrrent; but in the operation of my lamp in the case of an increase of current the consequent reduction of resistance in the vapor-path is compensated for by an increased resistance at the cathode, and vice versa. This particular form of resistance is a phenomenon that takes place under proper adjustment when thereis no chemical or physical action at the negative electrode. The feature of self-regulation is important whether the lamp be constructed to yield light merely through the instrumentality of the gas or by reason of the incandescence of the negative electrode, or both. In this lamp the resistances at diiferent points may be different at the time of starting from what they are when the lamp is running; but by properly adjusting the gas density the lamp may be made to start on the same current that it is designed to operate on.

In Figs. 2 and 3 I have shown the inclosing case in the form of a globe, the cathode being surrounded by an anode 2, made in the form of a ring. The operation of this lamp is essentially the same as already described with reference to Fig. 1.

Alamp of the character described in the foregoing specification will regulate its resistance so as to be operative under wide fiuctuations of electromotive force. Under increments of current the resistance of the heated cathode may increase; but this increase is compensated for by the change in resistance of the conducting gas or vapor through wide limits. In this Way a balance is brought about between the elements composing the luminous portions of the lamp, whereby the lampismadeself-regulating. Whenthelamp is operated by alternating currents, both electrodes may be regarded as cathodes. It is desirable that the material in the lamp should be such that there shall be no chemical action or physical change in the lamp while in operation.

The invention claimed is l. In an electric lamp consisting of an inclosing chamber, two electrodes within the chamber, an intervening gas Whose resistance decreases with increments of current flowing, and means for creating about the cathode a resistanceto the passage of current, the development of heat by the passage of current therethrough being sufficient to raise the cathode to a light-emitting temperature.

2. An electric lamp consisting of an inclosing chamber, two electrodes contained therein, the cathode being of such material as to become light-emissive under the influence of heat without undergoing physical change of state, and means for creating such resistance to the passage of current into the cathode as to develop sufficient heat around the cathode to render the cathode incandescent.

3. In an electric lamp having two separated electrodes and an inclosing chamber, a conducting gas or vapor, the Vapor or gas and one of the electrodes both constituting luminous elements, the resistances of said luminous elements being mutually corrective under increments of current.

1. In an electric lamp having two separated electrodes, one or both of which constitutes a luminous element, within the lamp, the vapor or gas contained Within the lamp constituting a steadying resistance.

5. In an electric lamp of the character described, a sealed chamber containing a conducting gas or vapor, a pair of electrodes within said chamber, a part of said chamber being substantially globe-shaped and having the cathode at or near its center, the anode being disposed in a ring surrounding the cathode.

6. A gas or vapor electric lamp consisting of a hermetically-sealed inclosing chamber, a ring-shaped anode therein, an exposed cathode Within the anode, and a gas or Vapor surrounding the anode and cathode.

7. In a gas or Vapor electric lamp consisting of a hermeticalIy-sealed inclosing chamber and a composite illuminating medium .or body therein, one element of which is a gas or vapor and the other a stationary solid body.

S. In an electric lamp of the character described, a composite illuminating medium or body one element of which is solid and adapted to become incandescent, the other element being a gas or vapor normally translucent and becoming itself luminous under the influence of the current through the lamp, and a hermetically-sealed inclosing chamber containing the same.

9. The combination with a protected cathode of the character described, of an annular anode surrounding the cathode, substantially as described.

Signed at New York, in the county of New York and State of New York, this 27th day of March, A. D. 1900.

PETER COOPER HEWITT.

Witnesses:

WM. I-I. CAPEL, CHARLES B. HILL.

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