US 2517126 A
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Aug. 1, 1950 Filed March 2, 1948 M. E. MACKSOUD INSTANTANEOUS STARTING ELECTRIC LAMP 3 Sheets-Sheet 3 INVENTOR.
, jmaw Patented Aug. 1, 1950 UNITED STATES PATENT OFFICE INSTANTANEOUS STARTING ELECTRIC LAMP Michel E. Macksoud, Newburyport, Mass, assigner to. Cooper-Hewitt Electric. Company, Ho-
boken, N. J.
Application March 2,1948, Serial No. 12,655
3 Claims. (01. 315-336) desired spectrum characteristics, but particularly it includes a means for instantly initiating the striking of the arc discharge in the mercury tube, thereby materially improving the eificiency of the sun lamp.
Another object of this invention is to further increase the efficiency of a sun lamp by the redesign of the arc discharge tube, which includes replacing the conventional starting coil usually mounted therein with one or more ionizing probe type electrodes. This construction permits the elimination of the conventional thermostatic switch assembly with its inherent mechanical'deficiencies, and as well the usual time delay factors involved for initiating the striking of an arc in the mercury tube just prior to its complete operation. This time delay, caused by the opening of the thermostatic switclrbreaking the electrical circuit to the starting coil, produces a flicker in the initiai. operation of the conventional lamp, which by the use of my inventionis elimi nated.
Another object of this invention is to increase the efficiency of a sun lamp assembly by utilizing a type of mercury vapor tube, having a pair of sharply pointed ionizing probe electrodes at each end of the arc discharge tube to facilitate striking an are at considerably lower potentials than the line potentials available from house current supply.
A further object of this invention is to make use of a probe type are discharge tube, having pointed ionizing probe electrodes at both ends of the arc, discharge tube, in order to facilitate the operation of the sun lamp on either alternating or direct current at the usual voltagesobtainable therefrom.
Another further object of this invention is to construct the probe electrodes in such a manner as to facilitate ionization of thegas content of the arc discharge tube at lower potentials than may be possible otherwise, by increasing the potential field established at the pointed ends of the probe electrodes.
These, and other features of this invention, will be best understood and appreciated from the described form and the two preferred embodiments thereof, selected for purposes of illustration and shown in the accompanying drawings, in which? Fig. 1 is a view of elevation of a'complete sun.
lamp portion of the bulb being shown as broken away to more clearly illustrate the position of" the component elements of the mount assembly.
Fig.2 is a view in elevation of another embodi- I ment of the sun lamp; portions of the bulbbeing shown as broken away to more clearly illustrate the use of the arc discharge tube having probe ionizing electrodes at each end of the arc tube;
Fig. 3 is a circuit diagram of the lamp mount assembly of Fig. I.
Fig. 4 is a circuit diagram of assembly of Fig. 2.
The sun lamp of Fig. l is shown as comprising Q a glass bulb I having transmission characteristics particularly efficient in ultra-violet spectra, tgsaid bulb ii preferably being etched on the inner surface thereof, and having a reflecting. surface 5* within the bulb terminating in. the cut-off line I, sothat the open face 9 of the bulb permits the racliations of ultra-violet and infra-red topenetrate therefrom upon an exposedobject. The-lamp bulb I cemented to an electric lamp base 3 having terminal connections 5! and 53. mount assembly sealed within the bulb l comprises glass stem ll, supporting lead wires 13 and i 5 and a mercuryarc diseharge'tubeE l-incandescent baliast filament l3 and 44 interconnected in. series together with the arc discharge tube 21"- and mounted in parallel adjacency thereto, and.
between the metalliesupporting platforms t1 and Z-i insulated; by the insulators and ailixed in position by. eyelets 25. The are discharge tube 2! comprises electrodes M at each end. of the arc discharge. tube and the probe ionizing electrode 36 having, a sharp point 3! on the end thereof, the probe electrode. being connected through its lead wire to the resistor 33 by means of con-- nection. 39, the other side of the resistor being The electrodes 280i the are discharge tube 21 are connected in. series. with the ballast filaments. 43. and by welded. to the. support lead [3.
meansoffiexible lead connections 38 and 49.;
Fig. 2 shows essentially the same component elements of the sun lamp of Fig. 1, the-principal difference bein the. structural features ofthe .arctube 2.1 ,having electrodes 28, and-spacedadthe lamp mount The sun lamp jacently to each of the oppositely disposed electrodes 28 are the ionizing probe electrodes 30 having sharp points on the ends thereof shown as 3|, each of said ionizing probe electrodes being connected in series with high resistances 33 and 36 through connections so as to establish a maximum potential difference between the ends of the probes 30 and points 3| and the are discharge tube electrodes 28 when electric current usually obtained from house current supply is applied thereto.
Fig. 3 illustrates a circuit diagram of the lamp mount assembly components of Fig. 1, which includes the arc discharge tube 21 and the series connected ballast filament 43 and 44 endin in the terminals of the lamp and 53. The ionizing probe electrode 30 is connected through flexible lead 39 to the resistor 33 and to the lead thereby establishing a potential charge at the terminus of the probe shown as the sharpened point 3i so that a potential differ" ence of sufficient value is established between the end of the probe electrode 35 and the adjacent main arc discharge electrode 28, so as to ionize the gas content of the tube 21. When alternating current is applied to the terminals of the lamp El and 53, on one half cycle, the potentials of this current source is instantly established at the terminal of the probe electrode 30 shown as the point 3i and adjacent electrode 28, the potentials established at these two electrodes being momentarily equal to the full line voltage minus the cold resistance values of the ballast filament 43 and 44 and the resistance 33. Ionization of the inert gas content (argon) occurs in the area of electrode 28 and. adjacent probe electrode 33. This serves instantly, not only to ionize the gas content of the tube, but also to heat the adjacent electrode 28 to some degree of electron emission so as to initiate an arc discharge between the electrodes 28. This function takes place in an extremely short period of time so that the effect of time delay between the function of ionization and subsequent arcing of the tube is unnoticeable. The resistor 33 being of considerably high resistance value and in excess'value to the resist-.
probe electrodes 30 and their respective adjacent electrodes 28.
In this type of sun lamp, the ionization of the inert gas content at each end of the tube facilitates a more uniform and instantaneous arc to be initiated particularly at lower applied potentials. This type of arc discharge tube when correctly designed in accordance with the disclosures of my invention, is readily applicable to be operated in conjunction with either alternating or direct current. In the case of direct current operation, one electrode serves as a cathode and the other oppositely disposed electrode serves as the anode of the arc discharge tube dependent upon the polarity of the direct current source of supply when applied to the lamp.
ance or voltage drop of the arc discharge in merely serves to prevent arcing between the" probe electrode 30 and the adjacent arc discharge electrode 28. Although the major arc discharge occurs between the electrodes 28, a minute current flows through the probe electrode 3!! and the resistor 33. This, however, does not detract from the efficiency of the lamp, as the current value is insignificant, the amount of such current being dependent upon the resistance value of the resistor 33, and the geometric design and spacing of the respectively adjacent probe and arc discharge electrodes.
Fig. 4 is a circuit diagram of the mount assembly components of the sun lamp of Fig. 2. The only major difference lies in the arc discharge tube 21, which is shown as having probe 36 and are each connected separately to the oppositely disposed probes so so as to etablish a maximum potential difference between the e This particular sun lamp assembly including a probe type are tube, eliminates the need for a thermostatic switch for starting the operation of the lamp. The important feature of this type of arc tube construction resides in the probe electrode design. In place of a starting coil filament, a probe electrode is utilized. In function, the probe merely cooperates to ionize the inert gas in the area in which it and the adjacent main electrode of the arc tube are placed. The ionization of the inert gas is sufllcient to initiate an arc discharge between the two main electrodes of the tube. The action is simultaneous, and appears to be instantaneous. The probe may be designed to have a sharpened point at its extreme end in order to increase the potential field at this point, and hence reduce the ionization potentials required. With a given applied voltage, the charge per square centimeter at the end of the probe will be much greater with the case of a sharp pointed probe than in the case of a probe that is not pointed. The per cent of change in the diameter of the wire to a point determines the effective increase in the charge. By charge is meant the quantity of electrical energ (quantity of electricity) or measure of displaced electrons. The probe is connected in series with a high resistance of a value higher than the resistance of the ballast filament, and the opposite end of this resistance is connected to the opposite side of the line so as to establish a potential difference between the probe electrode and the adjacent main electrode of the arc tube. More than one probe electrode may be utilized to effect ionization and to initiate the arc, although one probe electrode has been found to be quite sumcient. The series resistor for the probe is intended merely to limit the current flowing in the ionized path and to, thereby, prevent arcing between the probe and the adjacently disposed main electrode.
Referring to Fig. 3, in describing the operation of the sun lamp of Fig. 1, when alternating current of 50-60 cycles and having a potential of -130 volts, such as commercially supplied for home lighting, is applied to the terminals 5| and 53 of the sun lamp, on one half cycle, the maximum potential difference of the applied line voltage is instantly established upon the probe electrode 36 from terminal 51, through the resistance 33 and lead connector 39, as well as at adjacently disposed arc tube electrode 28 from terminal 5|, through lead I 3, ballast filament section 43, support hook 45, support platform 2!, support hook 45, ballast filament section 44, and connector 38. The potentials thus established at electrode 28 and adjacent probe electrode 30 are equivalent to the maximum line potentials minus the voltage drop effected by the cold resistances of ballast filament sections 43 and 44 and the resistance of probe resistor 33. However, the potential at the pointed end 3| of probe 30 may be of a correspondingly higher potential due to the electrical characteristics of this pointed probe electrode as previously described.
The potential difference thus established at electrode 28 and adjacent probe electrode 30 is sufficient to cause ionization of the inert gas content of the arc tube 21. Oppositely disposed electrodes 28 of the arc discharge tube 27 are coated in the manner described in my copending application entitled "Process for Coating and Activating Gaseous Arc Discharge Electrodes. These electrodes are highly electron emissive at relatively low operating temperatures, and have characteristics similar to cold cathodes. The ionization of the inert gas of the tube 21 particularly in the area of electrodes 28 and 30,0auses some degree of heating of the electrode 28 and the consequent electron emission produced thereby facilitates the striking of an are between the main electrodes 28 of the arc tube. The ionization of the gas content of the tube by this function of the probe electrode, also serves to vaporize a small quantity of the mercury deposit Hg in the arc tube 21, which increases the conductivity of the gaseous column within the arc tube. The mercury vapor and metallic deposit shown at 25 in the arc tube is only initially deposited thereon, but subsequently revaporizes and enters the are stream, as is also described in my copending application mentioned previously.
Referring to Fig. 4, in describing the operation of the sun lamp of Fig. 2, the function of the separate probe electrodes oppositely disposed and shown as 30 and 30, and each adjacent the main arc tube electrodes 28 and 28, cause ionization of the inert gas content at each end of the arc tube 21. This permits lower applied potentials to be used in order to insure starting of the arc discharge of the arc tube 21. This may be found to be desirable where the potentials of the supplied house current are of a lower value than standard potentials, or where these values drop to lower levels during periods of high loads. Separate resistors 33 and 36 are used to limit the current density in each respective probe electrode 28 and 28. This particular type of dual probe electrode construction incorporated in the arc tube 27 also facilitates operation on direct current, whereby it is immaterial whether the polarity of the current is applied in one direction or the opposite, since each of the oppositely disposed arc tube electrodes can function as an anode or as a cathode. On direct current operation, the use of a fixed condenser, which may be mounted within the base of the sun lamp and connected across its terminals 5| and 53, or across the terminals of the resistor 33 to the probe 30 and the adjacent main electrode 28, was found to facilitate the initial striking or firing of the arc, due to the charging and discharging effect produced by the condenser when direct current potentials were applied thereto.
The probe electrodes may also be coated to increase their electron emissivity, although they have been used successfully without any electron emissive coatings.
Having thus disclosed my invention and described two embodiments thereof, but Without intending to limit it to the construction as shown, I claim and desire to secure by Letters Patent:
1. An electric lamp comprising a mercury vapcr are discharge tube, a pair of arc discharge electrodes mounted in said tube in spaced relation, a sharply pointed probe electrode disposed in said tube adjacent each of said are discharge electrodes, an incandescent ballast filament connected in series with one of said are discharge electrodes, and a pair of resistors each connected at one end to one of said probe electrodes and at its other end to the opposite arc discharge elecrode, whereby a substantial part of the potential difference between said arc discharge electrodes is also established between each pointed probe electrode and the adjacent arc discharge electrode.
2. An electric lamp comprising an arc discharge tube, a pair of arc discharge electrodes mounted within said tube in spaced relation, a sharply pointed probe electrode mounted in said tube closely adjacent the first of said arc discharge electrodes, a ballast filament connected in series with the first of said are discharge electrodes, and a resistor connected at one end to said probe electrode and at the other end to the second of said are discharge electrodes.
3. An electric lamp comprising an are discharge tube, a pair of arc discharge electrodes mounted within said tube in spaced relation, a sharply pointed probe electrode mounted in said tube closely adjacent the first of said are discharge electrodes, a ballast filament connected in series with one of said are discharge electrodes, and a resistor connected at one end to said probe electrode and at the other end to the second of said are discharge electrodes.
MICHEL E. MACKSOUD.
REFERENCES @I'EED The following references are file of this patent:
UNITED STATES PATENTS of record in the