US2177696A - Gaseous electric discharge lamp device - Google Patents

Description

0a. 31, 1939. H. EWEST T GASEOUS ELECTRIC DISCHARGELAMP DEV ICE Filed Aug. 2, 1938 INVENTOR Hams Ewes'b BY 1/ QLMZM AT ORNEY Patented Oct. 31, 1939 UNITED STATES PATENT OFFICE P Q Gaseous mcigggcnmea time Hans Ewest, Berlin-Idchteri'elde, Germany, ailsignor to General Electric Company, a corporation of New York 3 Claims. (cl. 176-423) The present invention relates to gaseous electric discharge lamp devices generally and more particularly the invention relates to such devices of the high vapor pressure type.

I The light from the discharge in gaseous electric discharge lamp devices has a line spectrum and for many purposes it is desirable to complement the light'emitted by the discharge in the device with light of a different color. One

10 source of complementary light which is useful in" trode or a body mounted in or adjacent the discharge path between the electrodes without provision for means for supplying current thereto.

I have found that while such an arrangement as of a solid body in or near the arc discharge path in the device is satisfactory for low pressure discharge devices the use in high pressure discharge devices, such as devices in which the gaseous atmosphere is at a pressure higher than atmos- 80 pheric pressure and which exceeds 10 or even 100 atmospheres in certain instances, is accompanied by serious diiiiculties because the arc discharge has an extremely high temperature making the distancevof the solid body from the axis of'the 88 are critical. when the solid body is mounted too close to the axisof the are its temperature may exceed theevaporating temperature or the fusing temperature of the metal. hand if the solid-body is too remote from the 40 center of the are then it is not heated sufilciently during the operation of the device and does not emit light in the desired intensity. Small dis tances, such as fractions of a millimeter, determine the temperature of the solid body and, 48 obviously, the mounting of such a body with such critical exactness offers insurmountable diflieulties during the fabrication of such discharge lamp devices. s The object of the present invention is to pro- 60 vide a gaseous 'electric discharge lamp device of the high pressure type having a solid body mounted in heat receiving relation to the arc discharge in said device which lamp emits light from the arc discharge and the solid body heated by said I. discharge. Still further objects and advantagesv n the other attaching to the device and to its use and opera-v 7 tion will be apparent to those skilled in the art from the following particular description.

The invention attains its object bymounting the solid body at such distance from the axis of I the arc discharge that during the operation of the lamp the temperature of said body is below that at which the body emits light of desired intensity and by providing means to supply and control current to said body during the operation of the device. For regulating or adjusting the auxiliary heater current which flows overthe luminous solid body a manually operated or an automatically operating regulatable resistance is connected into the current lead of the luminous solid body so that it is possible during operation of the lamp to-adjust the luminous body temperature within wide limits according to desire. For example, the temperature of the luminous body is so controlled that, while taking into considera- 80 tion the required life span of the lamp,'the'most favorable efliciency and'luminous density is obtained, or the mixed light from the are discharge and from the luminous solid body, has the most favorable spectrum is used.

In the preferred structureof the lamp device the current lead for the solid body is connected to the current lead of one of the thermionic electrodes through an adjustable resistance. In such 8 a device an auxiliary heating discharge occurs between the solid body and the thermionic electrode other than that to which the current lead for the solid body is connected. The magnitude of the current flowing in the auxiliary discharge, 85 incident at the solid body is regulated by said series resistance so that the solid body, which for the purpose for which it is not brought to the desired temperature by the main arc discharge, is heated to said temperature by the additional heating thereof by the auxiliary discharge incident thereat. Further, the solid body connected in this manner is an. auxiliary electrode which facilitates the starting of the main arc discharge in the usual manner.

- In- Fig. l of the drawing accompanying and forming part of this specification an embodiment of the invention is shown in a front elevational view. a

Fig.2 .of the drawing is a wiring diagram of a circuit for the lamp shown in Fig. 1. 5C

" Referring to the drawing the gaseous electric discharge lamp device comprises a vitreous container l-,--such as a quartz container or a high softening point glass container, having two thermionic, activated electrodes 2 and l sealed there- 88 in. Said electrodes 2 and 3 are mounted on leads 4 and 5, respectively, which pass through the wall of the container I into the base I5 attached to said container I and which are fastened to the contacts 6 and 1, respectively, of said base I5. Said electrodes 2 and 3 are separated a distance of about 6 mm. and consist of a hollow, perforated metal shell, such as a tungsten shell, containing a quantity of material having electron emissivity characteristics, such as barium oxide, strontium oxide or a mixture of such oxides.

Said container I has a spherical part in which said electrodes 2 and 3-are mounted, a bell shaped dome having a heat reflecting coating, such as a silver coating, on the outer wall thereof and a bell shaped perforated bailie 9 mounted in said dome with the open end thereof above the discharge path between said electrodes 2 and 3. Said container I has'a starting'gas therein, such as argon, or neon or a mixture of these gases, at a pressure of about 1 to 20 mm. and a quantity II of mercury in such amount that it is wholly vaporized at a temperature lower than operating temperature of the container I and at a desired high operating pressure. During the operation of the lamp device the hot vapors from the discharge flow upward into the bafile 9 and through the perforations I0 therein and the particles which are sputtered ofl the electrodes are carried upward by the convection currents into the baflie 9 where they are deposited so that the light transmitting spherical part of the container I remains free from light absorbing deposits of such sputtered electrode material. such as a tungsten sphere or a tantalum carbide sphere, is supported in said container I by the current lead I3 which is connected to the contact I4 of the base I5. Said body I2 is mounted along the discharge path between said electrodes 2 and 3 and about 1 mm. from the axis of said discharge path.

When potential is applied across the electrodes 2 and 3 a discharge starts in the device, which discharge is conducted by the starting 'gas. The

heat from this gas discharge vaporizes the mercury and the vapor pressure gradually rises until all of the mercury is in the vapor phase and a vapor pressure of about 30 atmospheres is'produced. The are discharge is then a constricted one of narrow cross-section and the heat from this constricted discharge heats the body I2 almost up to the desired temperature thereof. The contact I4 is ,then connected with the contact 6 or 'Iby an adjustable series resistance and an auxiliary discharge occurs between the body I2 and the solid electrode 2 or 3. The current strength-of this auxiliary discharge is easily con-v trolled by means of the auxiliary resistance so that the body I2 is at the desired temperature during the operation of the lamp. In Fig. 2 of the drawing a circuit including a ballast re,-- sistance I1 is shown in which the body I2 is connected to the electrode 3 through said leads 5 and I3 and an adjustable resistance I6 connected in series with said body I2.

, When the characteristics of the current supply in the location where the lamp is to be used are known it is then possible by trial operation to determine the size of the series resistance required to control the temperature of the luminous solid body and to mount this resistance in the base Ii 5,- connecting it to either the current lead A solid body I2,

3 or 5. The third contact I on the base is then not necessary and the series resistance need not be an adjustable one.

While the container l of the device described above has therein a starting gas and a quantity of mercury it will be understood, of course, that this is the preferred embodiment of the invention and that the discharge conducting, luminosity producing gaseous atmosphere in the lamp device consists of gases, vapors, or mixtures of these to obtain light of a color suitable for a particular purpose, when desired. The position of the solid, light emitting body relative to the discharge is determined by the size of the body, the arc current and the vapor pressure and when these three are suitably proportioned the solid body can be mounted wholly or partly in the path of the arc discharge, when desired. When desired, a multiplicity of solid bodies, each consisting of a difierent material emitting distinctive colored light, are mounted in the lamp device and are caused to emit light alternately or simultaneously by controlling current fiow thereto individually. When the main arc discharge supporting electrodes are connected across the terminals of an alternating current source and the luminous, solid body is connected to a direct current source I prefer to connect the solid body as an anode.

While I have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and detailsof the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention, for example, the solid body is provided with a heater to control the temperature thereof, when desired.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A gaseous electric discharge lamp device of the high pressure type comprising in combination, a container, thermionic electrodes sealed therein, a gaseous atmosphere therein, and a refractory metal body mounted in heat receiving relation to the arc discharge path between said electrodes, means to supply electrical energy to said metal body and means to control the temperature and the light output of said body.

2. A gaseous electric discharge lamp device of the high pressure type comprising in combination, a container, thermionic electrodes sealed therein, a gaseous atmosphere therein, and a refractory metalbody mounted in heat receivin relation to the arc discharge path between said electrodes, means to supply electrical energy to said metal body and an adjustable resistance connected in series with said body to control the temperature and the light output thereof.

3. A gaseous electricdischarge lamp device of the high pressure type comprising in combination, a container, thermionic electrodes sealed therein, a gaseous atmosphere therein, and a refractory metal body mounted in heat receiving relation to the arc discharge path between said electrodes, said metal body being connected to one of said electrodes through a series resistance to serve as a light emitting, auxiliary electrode during the starting and operation of said lamp device.

' HANS EWEST.

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