US2205000A - Electric lamp - Google Patents

Description

June 18, 0' H. .1. SPANNER- ELECTRIC LAM Filed Dec. 14;. 1936 2 Sheets-Sheet 1 June 18, 1940. H. J. SPANNER' 2,205,000

' ELECTRIC mar Filed Dec. 14, 19:56 2 Sheets-Sheet 2 ENVENTOR f/Axvs J JfiAA/NEE Patented Jane is, 1940 UNITED STATES PATENT OFFICE Application December 14, 1936, Serial No. 115,685

In Germany December 13, 1935 4 Claims.

(Granted under the provisions of sec. 14, act of March 2, 1927; 357 0. G.

This invention relates to a new. form of discharge tube which may be used especially for illumination and irradiation purposes.

' As an improvement on the so-called sun 5 lamps it is proposed to operate such lamps, no longer with low metal vapor pressure in flat shaped tubes, but according to the present invention there is produced a high pressure or even super-high-pressure in the more or less small tubular form vessel using other characteristics of the sun lamp.

The construction of the sun lamp is characterized by a tungsten incandescent filament hav ing near its ends tungsten blocks on which the Edison effect occurs in the form of a low pressure mercury vapor discharge; the mercury is located in the lower fiat part of the discharge vessel and by means of the heat of the incandescent filament is gradually heated so that a pressure of the order of 10 mm. of mercury is attained.

Metal caps on the outside-of the fiat part and indeed as far as possible over the place on which the mercury lies have been used with such lamps for increasing the vapor pressure. The mercury may become somewhat warmer by this screening oil of the radiation; but even then it is not possible to attain a pressure above mm. This pressure corresponds approximately to a temperature of 225 C. which, of course, must exist on the entire discharge vessel before this pressure of 30 mm. can be attained between the electrodes.

These sun lamps have a great disadvantage because within 200 hours they are already so blackened by the sputtering of tungsten that no ultraviolet rays escape through the glass. Thepresent invention avoids not only this disadvantage of early darkening but brings a great advantage by use of high metal vapor pressure and high radiant output connected therewith.

rials specified in the following are given only as examples. One can, e. g., use in place of mercury other metals and also such metals in mixture with mercury and in mixtures with one another,

and with one or more of them supplied in accurately measured amounts.

Fig. 1 is a view in axial section of one embodiment of my invention;

Figs. 2, 3 and 4 are wiring diagrams respectively of three alternative circuits combining resistors and gaseous discharge in series;

Fig. 5 is a plan view showing the carrier for the radiant resistor;

body

' the high pressure are the filament takes a lon The novel invention will now be described by means of an example. The dimension and mate- Fig. 6 is a view in c'ross'section of a unit combining a radiant resistor and discharge tube within a common reflector; and

Fig. 7 is a view in axial section of a discharge tube for ultra-violet purposes with auxiliary 5 means to prevent formation of deleterious nitrogen oxides.

As already indicated above the novel discharge vessel consists of a tube, which suitably is bent correspondingly into the form of the arc, and an 10 incandescent filament. With the production of high pressure it is especially'notable that the arcing points, i. e., the tungsten blocks, which accordingv to the invention can also be activated, e. g., by alkaline earth oxides, which for their part are worked into a core material (tungsten of porous form) and are in great part reduced to metals as, for example, metallic barium. In-

' stead of following the shortest potential path for er path electrically such that the arc cannot jump across onto parts of the incandescent filament. In which case there wouldbe either a premature burning through of the tungsten filament used for starting and for light emission, or at least so strong a vaporization of the tungsten that the glass wall would thereby be blackened.

As previously mentioned the arcing point should be activated, so there is no high cathode drop, which of itself would contribute to the darkening by vaporizing of the tungsten electrode.

The light emission of the tungsten block would by this be strongly decreased since the temperature with use of barium is decreased from 2500 C. to about 700 C. In case one desires an efiicient light radiation from the arcing point, one must use other activating materials, as for example thorium, especialy thorium compounds. In this case, however, a somewhat stronger sputtering occurs than with the use of barium. 40

The discharge tube may advantageously be so curved that between the arcing electrodes, which can also be formed as the various so-called shortcircuited self-heating electrodes used in the art today with the modern metal vapor lamps, there exists'a better arcing possibility than at the nearby points of the tungsten incandescent spiral. Obviously, all points on the incandescent spiral need not and cannot be spaced farther from the arcing point than the electrodes themselves, since the high pressure are will seek not merely the shortest linear path but the steepest potential gradient. The envelope thus is kidney shaped toward the upper part with the incandescent filament near the top and the arcing points at the lower part of the kidney. In order that the arc should follow a path as long as possible and advantageously be curved corresponding tothe discharge tube, one may use deflecting means for the are, as for example screens in the discharge path or magnetic apparatus outside of the discharge tube. In this way the result that all parts of the discharge envelope are substantially equally heated is attained. This is necessary especially when glass instead of quartz is used in high pressure discharge tubes.

If a single part of the tube nevertheless should not be particularly heated, any means may be used for hindering the heat dissipation and radiation, as for example double walled vessels, metal covering or jackets of insulating material. In Fig. 1 is shown a sealed light-pervious envelope I, in which are contained electrodes 2, mounted on lead-in wires 3, brought through the envelope in seals 4. The incandescent filament 5 is connected between the lead-in wires 3, at some suitable point 6.

Obviously, the inventive concept can also be applied to a similar three part tube for use with multiphase current.

The physiological action of ultra-violet rays can in known manner be increased very considerably by the simultaneous action of visible or infra-red rays. It has, therefore, been suggested to use for medical purposes irradiation apparatus which includes an ultraviolet radiator and a radiator for visible light or infra-red. As ultraviolet radiator there has been used for example a mercury vapor lamp of quartz or other material permeable to ultra-violet light. The visible or infra-red radiation has been produced by an electrically heated incandescent body. To simplify its service, it is customary to connect such irradiation apparatus to a constant potential source, although the starting and the burning potential of the ultra-violet radiator vary very considerably from one another. on account of this variation and for stabilizing the luminous are, a resistance ballast is necessary, which limits the current during the operating condition in which the potential on the lamp is lowest.

In case the potential during the heating up of the lamp is higher than after the heating-up period, there is a greater electrical loading converted into heat in the ballast resistance during normal burning than during the heating up period. By suitable choice of the ohmic resistance and the dissipation capacity of the ballast resistance it is possible to attain the condition that the ballast resistance during the normal burning of the ultra-violet radiator assumes a temperature at which it emits a mixture of visible and infra-red radiation especially desirable for sup-v diation, the burner potential increases strongly,

during the heating-up period. The energy converted into heat in the ballast resistance is therein significantly greater during the heating-up period than during the normal burning. It is not possible with these burners to choose the current line.

ohmic value and the heat dissipating capacity of the resistance so that during the normal buming the desired mixture of visible and infra-red rays are emitted. The temperature must be so high in order to reach the desired physiological action that the greater energy converted during the heating-up period would have as a consequence a thermal excess in the ballast resistance. Because of these considerations it has heretofore been the practice to keep the temperature of the incandescent body during normal operation below the desired emitting temperature.

These disadvantages are avoided with the irradiation apparatus according to the invention. This irradiation apparatus consists in an electrically heated incandescent body which advantageously may also serve as ballast resistance for the ultra-violet radiator. Thereby an ultraviolet radiator is used, the potential drop of which increases at least during the end of the heatingup period and of which the normal burning potential also increases more or less within the current range suitable for its operation.

The apparatus is distinguished from irradiation apparatus heretofore known in the art in that means are provided by which the temperature of the incandescent bodies after the heating-up of the ultra-violet radiator can be increased by varying the supplied energy and/or the superficial heat dissipation, preferably automatically. In this way it may be arranged that the temperature of the incandescent body during the heating-up period is not too greatly increased and that moreover, during the normal burning of the ultra-violet radiator, it comes as near as possible to the value necessary for the physiologically favorable action.

The drawings, Fig. 2, show in part diagrammatically one example of the invention. An ultra-violet radiator I3 is connected across two series-connected resistances l4 and i5 to the terminals Il'and ll. of a direct or alternating Parallel to the resistance H, a switch I6 is connected. The resistances are so dimensioned that the current during the heating-up .period does not exceed the highest permitted value. After the heating-up of the ultraviolet radiator the switch IE is closed, advantageously automatically.

The resistance I5 is so dimensioned that it limits the current in the normal operating current. Through the short-circuiting of the resistance H, the current which passes through the ultra-violet radiator l3 and the resistance I5 is increased. This current increase is about suflicient to increase a little the potential drop on the burner with increasing current.

It is especially advantageous, therefore, to use a metal vapor burner with a limited dosage of the vapor. With such burners, the amount of the metal contained in the vapor in the current range suitable for operation increases only a very little with increasing current. With increased loading, therefore, the vapor pressure in this range increases only a little, and the vapor becomes ever less saturated. This phenomenon has a consequence significant for the present problem that the potential drop in the current range lying in the upper half of the current values depends only very slightly on the degree to which the metal provision available for vaporizing is actually vaporized. For this reason ultra-violet radiators with incandescent cathodes, and especially those with electrodes heated by the discharge itself oiIer a special advantage that it limits the current after the heating-up to a normal value. During the heating-up period a greater current fiows because the potential drop in the burner is less than during normal operation; the resistance, therefore, absorbs during the heating-up period a greater amount of energy than thereafter. According to the invention; therefore, it is so arranged and constructed that during the heating-up period no unpermissibly high temperature is reached.

During the normal operation too low a temperature would, on account of this, be maintained I if there were not according to the invention a second resistance l8 provided in its neighborhood and especially on or in the-inside of its supporting body, which second resistance can be connected by the switch is likewise to the terminals H and I! of the line.

After the heating-up, the switch I, advantageously automatically, is closed so that the supporting body 20 of the resistances l1 and li is more strongly heated than by the resistance I! alone.

The resistances are so dimensioned that in this operating condition the incandescent body provided with both resistances or the resistance material itself attains a favorable temperature. for the supporting of the physiological action of the ultra-violet radiator.

Fig. 4 shows a further example of the invention. The ultra-violet radiator I3 is during the heating-up period connected in series with the resistances I1 and I8 and the switch 22 to the terminals II and I! of the line. After the heating-up, the switch 2! is closed and the switch 2! opened so that the ultra-violet radiator i3 is connected to the line through the resistance 11 and the switch 21. The resistance l8 after the switching into series with the resistance 23, is likewise connected to the line. The three resistance wires are, as shown in Figs. 5 and 6 wound onto a common carrier body 20. By a suitable dimensioning of the three resistances it is possible to obtain a temperature of the incandescent body or the resistance material during the normal burning favorable for the supporting of the action of the ultra-violet radiator. This arrangement has the advantage that the proportion of the energy of the ultra-violet radiator to the energy of the incandescent bodycan be better adapted in many cases to the need.

It is in general desirable to arrange the ultaviolet radiator and the incandescent body in a common reflector as shown for example in Fig. 6. If an incandescent body is used of the form shown in Fig. 5 a cylindrical mirror is especially suitable as the reflector.

For automatically controlling the switches l6,

l9, 2| and 22 in response to the operating conditions of the ultra-violet radiator 13 one can use known switching apparatus. Since the starting potential is essentially higher, and the potential during the heating-up period is essentially lower, than the normal operating potential, one makes use of a potential relayimpedance connected in parallel to the ultra-violet radiator, which under circumstances of the present invention can be overcome by intervention of a delay apparatus. By such an arrangement it is possible to avoid response of the potential relay during the short starting process.

In many cases it is advantageous to use a relay which is traversed by the burner current and which switches over or closes the switches l6, l9, 2| and 22, if necessary with a time delay after termination of the heating-up period.

An arrangement which is characterized by special certainty of operation is one in which, for the functioning of these switches, one makes use of a relay responsive to energy converted in the burner or of a relay which responds, e. g., linearly, to the current as well as to the potential. By use of such relays an overloading of the incandescent body or the radiators can be avoided if the duration of the starting or heating-up period were to be seriously lengthened by special conditions. Such a disturbance could for example occur with a very low ambient temperature.

In many cases, it is desirable to substitute, in normal operation, another resistance wholly or partially for the ballast resistance used during the starting and heating-up period, which is so arranged and constructed that with the normal current of the burner it attains a temperature favorable to the desired physiological action. The switching apparatus must, of course, be so constructed that the switching'occurs without interrupting the burner current. A brief reduction. or increase in the burner current during the switching-over can be permitted. Examples shown in Figs. 3 to 6 inclusive can be used with especial advantage in this way if the available line potential is not much higher than the normal arcing potential of the radiators, so that the energy radiated from the resistance, with the connections according to Fig. 2 standing in a suitable relation for emission of ultra-violet rays from the burner.

It is not suflicient that the-incandescent body should reach a definite temperature: its radiating surface must also have a size depending upon the energy of the ultra-violet rays.

For the reduction of the highest temperature reached during the heating-up period, it is desirable in many cases to use an incandescent body with a very high heat capacity.

If a material with a strong positive temperature co-efficient of specific resistance is used asv the resistance material, and by the selection of the arrangement therefor care is taken that the temperature strongly increases with increasing energy loading, the demands of the burner dur-- ing the starting-up period can be substantially reduced. To this end for example an incandescent filament lamp with tungsten filame'nt or an iron hydrogen resistance can be used.

If a material with negative temperature coeillcientof specific resistance is used in an arrangement with sufliciently large heat capacity, it is possible for the low value of the resistance requisite for normal operation to be reached first at the end, or after the ending, of the heating-up period. In this way such an increase of the energy emission from the incandescent body is attained, without switching over, that, with proper dimensioning and choice of the heat dissipating capacity, its temperature attains a value favorable for the physiological action.

Several compounds of oxygen alone, as e. g., the ozone, and of oxygen with nitrogen, e. g., the so-called nitric oxides N20, N02, N205, are formed in the atmospheric air by the utmost short wave UV-rays of quartz lamps; the ozone is even able to form also other unknown nitric oxides and it may be by combining with the other known nitric oxides mentioned above. (See M. Moeller, Das Ozon, Edition Vieweg, page 117.)

These nitric oxides, as is known, are extremely damaging to the human organism, especially to the lungs. One has been forced to take from the ultra-violet irradiations besides the favorable eifect of the UV also the unfavorable effect of the nitric oxides.

According to the form of the invention .illustrated in Fig. '7, one allows only oxygen to reach the quartz burner, which emits the rays; and one avoids also especially that the ozone generated near the burner will mingle appreciably with nitrogen which may be also in the neighborhood of the burner.

Several apparatus are known in the industry for blowing away oxygen or other gases. An especially effective apparatus consists in one that circulates the oxygen in the direction along a tubular burner; for this purpose the burner is provided on one side with an apparatus in the form of a capsule, which forms together with the burner, a ring shaped jet or blowing device. In order to build this apparatus more effectively, one can attach such a device also at the other side of the burner, so that two oxygen streams meet each other in the middle of the burner,

where the ultra-violet rays are strongest.

It is important that the quartz burner should reach a temperature of at least 350 C. for generating'the high pressure discharge; therefore, one can use only such burners, which are not disturbed in their function by the cooling of the oxygen streams. Such burners have appeared on the market for about three years, produced by the Hanovia Companies as so-called "metal dosage burners. In these burners the mercury is in a super-heated state. If it should happen that the cooling-of these burners by the oxygen is still too strong, the burner need only be overloaded by a higher current, e. g., instead of using 300 watts, one may use 400 watts.

In this way one gains according to the invention, the well known effects of ozone which is so effective on the organism besides the favorable effect of ultra-violet rays. This apparatus with oxygen should be used at least for sick people. It is impossible to cure the body on the one hand by ultra-violet rays while poisoning the body on the other hand by nitric oxides. Besides this,

- the ozone has a much stronger effect to kill bacteria than the nitric'oxides, so that also a third advantage is achieved by using the invention.

The burner of quartz or other material 26 which furnishes the short wave ultra-violet rays It may be also mentioned that this metal capsule can be used at the same time also as lead for the electric current. In this case, however, one should provide also an insulating cover on the capsule in order to make it shock prool'.

As is illustrated furthermore on the drawings a stream line is formed by using the two blowing devices attached on the two pole vessels; this stream line is symmetricalfand is turned outward from the middle of the burner. the numbers 32, 33 and 34 illustrate that the air 33 from outside cannot touch the burner when the stream 32 of the oxygen is fairly strong and therefore a stream 34 of oxygen with great amounts of ozone is emerging from the nearest neighborhood of the burner outward.

It is obvious that one can use instead of the quartz in the wall of the burner any of the special glasses which let through sufficient short wave ultra-violet rays for the purpose of generating the ozone.

What I claim is: v

1. A radiant electrical discharge device comprising an envelope permeable to at least a part of the radiation from the discharge, a filling therein adapted to provide a gaseous atmosphere for the discharge and including a vaporizable material in amount suflicient to raise the voltage of the discharge as hereinafter defined, a plurality of electrodes spaced therein, and a high resistance thermionic filament extended along the space between the electrodes and adapted to be heated to thermionic temperature by the current passing therethrough, and a source of current in circuit with such filament and the elec trodes adapted to provide current sufficient to heat the filament to thermionic temperature and at a potential greater than the striking potential of a discharge in the ionized filling between the electrodes, the envelope being so dimensioned with respect to the current loading provided by said source to the discharge and the filament as to produce temperatures in the envelope at which the resistance of the dis charge path is raised by evaporation of the vaporizable material of the filling to maintain a voltage between the electrodes at which the thermionic resistance filament is maintained at incandescence by current fiow therethrough in parallel to the discharge.

2. A radiant electrical discharge device as defined in claim 1, in which the envelope is curved upward and the thermionic conductor is placed near the curved wall of the envelope so as to be away from the destructive effect of the arc.

3. A radiant vapor electrical discharge lamp which comprises a sealed envelope permeable to at least a part of the radiation of the discharge and of an incandescent body, arcing electrodes spaced apart in said envelope, an incandescent filament within said envelope electrically connected to said electrodes and in parallel to the discharge path between them, and filling material therein adapted to provide an atmopshere for the discharge including a vaporizable material in amount suflicient to raise the voltage of the discharge after starting to a normal operating value at which the filament is maintained at an efficient radiating incandascence, and the heat dissipating capacity of the envelope is adapted to assure said increase of arc voltage by vaporization when operated from a current source capable of maintaining the filament at incandescence above said normal operating voltage when the arc is extinguished.

The lines with 4. A radiant vapor electrical discharge lamp which comprises a sealed envelope permeable to at least a part of the radiation of the discharge and of an incandescent body, arcing electrodes spaced apart in said envelope, an incandescent filament within said envelope electrically connected to said electrodes in parallel to the discharge-path between them, and a filling therein adapted to provide an atmosphere for the discharge including a vaporizable material in amount which when fully vaporized will raise the voltage of the discharge after starting to a value near but below the starting voltage of the arc, the filament being in heat-exchange relation to the arc path, whereby its temperature with a given current loading will be higher when the arc is operating than if the arc were not operating.

- HANS J. SPANNER.

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