US1030178A - Apparatus for the electrical production of light. - Google Patents

Description

P. c. HEWITT; APPARATUS FOR. THE ELECTRICAL PRODUCTION OF LIGHT.

APPLICATION FILED APB.11, 189B. 1 ()3'Q 178 Patented June 18,-1912.

WITNESSES:

@. /9.7l1m"l- I I I 1 I UNITED STATES "PAT NT. OFFICE.

PETER COOPER HEWITT, OF NEW YORK, Y., ASSIGNOR TO COOPER HEWITT ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

APPARATUS roa m ELECTRICAL rnonuo'rron or LIGHT.

A man filed April 11, iaaa. Serial No. 677,199.

To all whom it may comma Be it knownthat 1, PETER COOPER HEW- n'r, of the city of, New-York, boro h of Manhattan, in the county and State-o New York, have invented certain new and useful Improvements in A paratus for the Electrical Production of lght, of which the following is a full, clear, and exact description.

new and useful means of roducing light by electricity, whereby a; light of high illuml nating power isproduced', and the intensity and color of the light may be varied. V

I have discovered that certain vvapors of specific density and physical condition have the propertyof becoming intensely hght radiant when an electric. current is passed I through them. Such a vapor-is the vapor of mercury, sodium, iodin and other metals, gecuhar epends each producing a light with colors to itself. The light givinglquality chiefly on the density of t e vapor, as well as the material, it being most intense at the point of saturation, or boiling paint of the metal, the light giving quality somewhat proportioned to the density. esides simple metallic vapors, other gases have this propertyto acertain extent, but most of them are objectionable on account of the temperature necessary, and also on account of the electrical resistance at the point where their vapor is in the physical state,

which allows them to be light radiant. For

these reasons their use in many cases is impracticable. In the case of mercury, which 1s a fair exampIe of a metal volatihzlng at a practical temperature, the vapor is inclosed or formed in atube whose ends are turned 6 down so as to .hold a globule of mercury,

into which are led wires for conducting the electrical current, which wires may be submerged in the volatizable materialor not, as desired. In case the wire or electrode projects through the .material to be volatilized $5 the becomes heated on the discharge o 59 not snfliciently full of vapor.

tin-electric current, which in turn heats the material to be volatilized andvolatihzes 1t,

an" the this w th-seam; it the tube is.

-.not'a ready o'f such a temperature that it is It is ,well known that a' .wire leading into an-attenuated atmosphere becomes heated, although the same sized wine will conduct the circuit under ordinary conditions without heatlnig. In the? case where the material to be volat Theobject of my inventioniis to provide a ized constitutes the electrode, the current .heats the electrode direct, producing the same effect. A .tube may be-constructed contalnmg an exact amount of vapor (or material toproduce the vapor) necessary to roduce this intense light. electrically, in w ich case the exact degree of vapor density and Specification e: I -etters Patent. P t t u 1912.

physical condition can be produced which is I most advantageous. The electrodes must be made of such size-as not to be deteriorated by the electrical'disch'arge. The light actlon of these tubes is intermittent and the electric current impulses or oscillations can be made withthe frequency desired, and so rapid as to require a .most delicate instrument to detect that the light is not continuous. A tube in the form described, one quarter of an inch in diameter,-one foot in length will produce a light too brilliant to look at, the light beingmore thana hundred candle power. The quantity of light may be varied by the current used, from great brilliancy to the bare luminosity of ordinary vacuum tubes or Geisler tubes. This tube is practically indestructible, having nothing to ruin or destroy, operating at somewhere about a temperature of 300 C., if mercury is used. In the case where other metals or materials are used, my tubes operate at the temperature a little above the point or thereabout, of thesubstance in a vacuum. It ,is advisable to use a substance which volatilizes at ordinary temperatures as near as possible, for economy. The metal'rubidium gives a deeper red light than any other, and I prefer to use this metal or a metal having a deep red band in the spectrum, or a proportion of this metal to obtain a deeper red color in my tubes. Potassium, also 'thium give fair results, the temperatures being higher. In practice a more agreeable light will be produced by the judicious use of two or more tubes, each containing difierent vapors.

In orderto more fully explain my invention, reference is had.to the accompanying drawing forming a part of the specification, in which similar charactersof reference indicate corresponding parts in all the figures.

Figure 1 is a side elevation of one formof a plant for producing light; Fi 2 is a side elevation of a modified form 0 tube; and Fig. 3 is a longitudinal section of a straight tube having a volatilizable material. at one end only.

A is an electric generator, B is a transformer, C a condenser, D D" wires, terminat ng in the electrodes E E, extending into the volatilizable substance F, contained in the bulbs G G of the vacuum tube G. e

The form of converter shown in Figs. 1 and 2 is shaped and arranged like an inverted letter U. The two legs of the U are shown similar and symmetrical,.as are also the electrode chambers, the bodies of liquid therein and the leading-in wires. From this symmetrical arrangement it results that when an alternating electromotive force is impressed first on one electrode and then on the other as by the transformer B, or by condenser C, or by both together, the fluxes in both directions, find substantially the same physical and electrical conditions at their respective electrodes and the operations and reactions are the same for each half wave except that the directions are re versed. v

To operate my light, I use an electric current of varying voltage, having found that from 500 to 5,000 volts most successful, but it can be operated at many other electrical pressures, depending. on "the length of the tube G desired to operate, and the quantity of light to be produced; also for the material used. Iplace across the wires D D lead-' ing to the tube G the condenser Cwhich is of suitable capacity; the object of the con denser being to accumulate the electric current during the minute period of time when the current is notpassing through the tube G, and deliver the accumulation to the tube G during the time the tube is taking current. The condenser also aids the light giving quality of the tube. This condenser C-being in resonance with the tube G and-with the source of current, will adjust the voltage of thee urrent in some degree to any varying resistance that may occur in the tube. The tube itself is a condenser of certain capacity under the condition that I establish, and under light giving conditions is oscillatory or intermittent, acting somewhat as a dis-' charge for the condenser, producing waves or pulsations in the current from the condenser. The tube G is constructed with the volatile electrodes E E in the bulbs G, G G G and is proportioned in size to the current to be used. The resistance of the vapor in a high degree of attenuation is greater than it is when it becomes a little more dense; then becoming more dense the electrical resistance increases so that if the electrodes overheat, the vapor generated will shut off the electric current imtil they are again sufiici'ently cool, but with a properly constructed tube the volatilized mercury will condense atsubstantially the same rate at which it is volatilized, so that the shutting olf of the current dces not occur except through accident and in any g1ven' case may obviously be prevented by any means which will decrease the rate of evaporation or increase the. rate of condensation. 'At a conpor to flow through the tube, or generate in the tube and flow into the pump until it has carried away with it all the impurities existing in the tube. When this is accomplished at .the required vapor density (pressure and temperature), the fact becomes self-evident by the great quantity of light coming from the tube. The quantity of light is approximately proportional to the vapor density. The quantity' of light is under absolute control, electrically or otherwise. I have found it --ad\-'antageous, even when operating tubes at almost atmospheric pressure temperature. to prevent radiation of heat to avoid the heat loss. As the vaper in the tube is very attenuated in the case of metals that volatilize above the atmospheric temperature, it may become necessary in the economical use of some of them to use a starting device to acquire the proper vapordensity on starting.*- Such a starting device may consist of applied or external heat or an increased electrical potential for the time beings: I'have found in the case of mercury where the tube operates at about 300 C. that by' supplying from an outside source, the heat which otherwise would be radiated-from the tube, I have a somewhat -correspondingincreased production of light.

Infact, with the tube operating at this temperature, which tube maybe of the dimensions-set forth in the early part of the specification, a brilliant light of especially high efliciency may be secured, even without the supplyin of heat from an outside source. These tu es may be made in almost any shape from spirals to straight tubes, or inverted U-shaped tubes, or U-shaped tubes; but'in the case of a U-shaped tube used for volatile material I prefer to use the invert-. ed U-shaped tube, shown in Figs. 1 and 2, but in some cases the tube may be used or formed with a downwardly curved intermediate portion containing a body of mercury which may fill the cross-section of the tube, so as to form a partition separating two vacuous spaces, or I may use two tubes jointed together and having a body of mercury at the point of juncture. In order to equalize the pressure within the tube, I may provide the same with a reservoir Gr in communication with the interior of the tube to be filled with vapor, which, however, is not affected by the current nor rendered luminous, as the current does not pass through it, and hence the vapor contained therein can act as an equalizer to give the each end into enlargements,

In producing my tubes containing mor cury I have found that a very-small amount of oxygen or oxid of mercury in the tube increases in a marked degree the electrical resistance and impairs the light radiating quality. I have also found that the combination of two or more tubes, each giving rays of light of a different color, is advantageous.

I claim as my invent-ion:

l. A mercury vapor lamp comprising an inverted U shaped exhausted container with an enlargementat each end partly filled with mercury constituting electrodes.

2. A mercury vapor lamp comprising an inverted U shaped exhausted container with an enlargement at each end partly filled.

with mercury, and also provided with a regulating chamber communicating with the interior of the main chamber cut out of th path of the current therein.

3. A vapor electric lamp having a highly exhausted chamber formed in the shape of an inverted. U, havinga main light giving portion of uniform diameter expanded at said enlargements beingepartly-fi led with mercury con stituting'electrodes and a condensing chamber centrally located along said tubular portion whereby the vapor pressure within the container is re lated.

4. The combmation with a mercury vapor lamp including ahighl exhausted container having a curved tubu ar light giving por tion, two enlargements ofsaid tubular portions located at ldwer extremities in said container, and mercury electrodes at the extremities of said tubular portion, together with an electricsource therefor adjusted to maintain a .temperature of approximately 300 degrees centigrade in said-tube whereby an eflicient source of illumination is secured.

5. A mercury vapor apparatus comprising an exhausted container, suitable mercury electrodes therein and a light giving tubular portion thereof together with means for adjusting the density of the mercury vapor therein during normal operation to the density corresponding to approximately 300 degrees centigrade, said means consisting of bulbs terminating said tubular portion whereby additional condensing surface ,is

obtained for said vapor.

6. A mercury vapor apparatus comprising i an exhausted container, suitable mercury electrodes therein and a light giving tubular ortion thereof, together with means for adusting the density of the mercury vapor therein during normal operation to the density corresponding to approximately 300 degrees centigrade.

.7. A mercury .vapor apparatus comprising an'exhausted container, separated bodies of mercury therein operating as electrodes and a light givin portion of said container between said e ectrodes,'together with means for adjusting the density of the mercury vaporin sai container during normal operation to the density corresponding to 300 degrees centigrade approximately, said means consistingof portions of said container exposed to themercury vapor outside said light giving portion, whereby said adjustment of the mercury vapor density is obtained.

PETER COOPER HEWITT. Witnesses:

EVERARD BOLTON MARSHALL, GEO. M. HOPKINS.

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