US2278079A - Lag voltage controller and discharge lamp circuit - Google Patents

Description

March 31, 1942. Y J, J, KNOUSE ET AL 2,278,079

LAG VOLTAGE CONTROLLER AND DISCHARGE LAMPCIRCUIT Filed Nov. 18, 1941 ATTORNEYS enhance the lighting value of the glow'between I Patented Mar. 31, 1942 s PATENT OFFICE LAG VOLTAGE CONTROLLER AND 'DISCHARGE LAMP CIRCUIT Joseph LKnouse, Salem, and Richard S Stone,

Lynn, 'Mass., assignors Peabody, Mass.

to Bruce A. Coffin,

Application November 18, 1941, Serial No. 19,584 10 Claims. (Cl. 176-124) This'invention relates to gaseous discharge lamp, such for instance as thelam'p usedin fluorescent lighting at the present time, and particularly to such lamps which areoperable at or below the potential of the customary domestic source of electrical energy.

In lamps of this type wherein a gas-filledelectric discharge tube is providedwith oppositely disposed filamentary electrodes which are provided with a suitable electron emitting coating and heated from. a suitable source of electrical energy, to an electron emitting temperature, the

electrodes-are usually connected inseries with an inductor andsome capacitator across the terminals of the current source to produce the voltage drop to obtain the operating voltage of the lamp; and some device is connected in the series to interrupt the heating current after the electrodes have become heated sufliciently to. start a discharge at the electrodes, which interruption causes a greater voltage than normal. The arrangementtherefore was such that upon interrupting the series connected electrodes a voltage surge occurs, due to the inductance which builds up this voltage sufiiciently so that a discharge occurs between the electrodes. Automatic de-' vices have usually been provided called starters for the purpose of interrupting the series circuit.

The inductor is one of the more expensive parts, i

of the circuit, and'this inductor together with the capacitator usually must be shielded because of the disturbance which may be caused to parts with which it is associated.

- One of the objects of this invention is to eliminate the expensive inductor which is provided in such a circuit and to substitute therefor a pure resistance of a high resistance coeflicient arranged in such a way as to give the proper time lag required for heating the filament.

Another object of this invention is to provide a controlled current surge in the circuit.

Another object of this invention is to, utilize the heat generatedby such resistance voltage to the electrodes of our lamp.

' Another object of the invention is to arrange this resistance within the gaseous dischargelamp itself making unnecessary the. handling of-such with these and other objects in view, the in vention consists of certain novelfeatures of construction, as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawing:

Fig. l is a sectional view shown largely diagrammatic of a gaseous discharge lamp and illustrating the line source of potential as connected thereto.

Fig. 2 is an elevational view of the stem portionshown at the left hand end of Fig. l.

Fig; 3 is a diagrammatic view of the circuit.

Fig.4 is a sectional viewon line 4-4 of Fig. 2.

Figs. 5 and 6 are dlagrammatic'circuits show-' ing some modifications as may be employed in the use of this invention. r I

In proceeding with this invention we have eliminated theexpensive inductor which'is frequently used in the circuit of a gaseous discharge lamp such for instance as a fluorescent lamp which is supplied from the domestic potential. This inductor which provided the voltage drop and produced the voltage surge when the circuit was interrupted in order that a discharge might occur between the electrodes of the gaseous discharge lamp, is replaced by the use of unequal noninductive resistances connected in parallel'in the circuit so that the heat of these resistances will be distributed and a time lag will 0ccur.to permit the filaments to become hot, followed by a change in the current circuit to cause a dis-' chargebetween the electrodes. The pure resistance which we use may be made 'of rather small volume and may be supported within the gaseous discharge lamp itself. Thus the heat which is generated bythis resistance will increase the ionization of the'lamp 'thus giving a greater eificiency of light output; The resistance may operate by connection of different values of resistance in parallel permanently but under some conditions it may be desirable to permit the electrodes to heat before the parallel arrangement of the resistances is put in the aircult and accordingly we may regulate the time of cutting in'ofthe resistance in parallel by the use of a bi-metal switch so that desirable results of this delay may be provided for.

.We havev also found that the so-called starter or circuit interrupter, now a separate unit, and in many instances utilizinga rare gas for a glow discharge between'its electrodes, may be incorporated in the gaseous discharge lamp itself, thus eliminating the separate handling oi. a starter, and socket therefor, which has hereto forebeen provided. From this arrangement it will therefore be apparent that we may make an electric discharge lamp which for installation need only have sockets therefor provided and a separate handling of a starter or an inductor and capacitator may be eliminated. Thus the installation of a fluorescent lamp or gaseous discharge metal such as tungsten or the like in a coil which coil is coated with an electron emitting material.

such as an oxide of barium or strontium to provide a flow of electrons when heated. The lamp is usually evacuated and fllled with a rare gas such as argon at a few millimeters pressure so as to iacilitatestarting and to which is added a few drops of mercury.

' The source of supply-oi electrical'energy is usually the domestic house current, the terminals of which are designated l4 and I5 and as shown in Fig. 3 one terminal H is connected to the electrode l2 while the other terminal of the 1 electric source of supply is connected to the electrode II with resistance element I6, to be later iescribed in greater detail and a circuit closing switch I! interposed in this line. The two electrodes are connected together in series through a starter designated generally I8 which may be a known starter utilized in the. trade. or. the starter may be of a type to be mounted within the lamp which will be later described in greater detail. The circuit just described is similar to that already in use except that the resistance element I6 is diiierent and is supplied in the circuit instead of an inductor.

The starter designated l8 andincluding a condenser when used as a separate unit such as illustrated in Fig. 8, may be a starter of the type shown in the Bench Patent 2,200,443 or the Hayes Patent 2,228,210. Its function is to break the circuit automatically after suflicient heating of the electrodes has occurred. 4

In a circuit of this character it is-sometimes desirable to build up a voltage above the line voltage for starting, which we accomplish by a capacitor designated generally 19 shunted across the resistances l6 and as we have shown in Fig. 5 although under most circumstances where the lamp will start at line voltage we would not need a capacitor in this location.

The resistance unit It will be of a pure resistance character and will comprise two sections of resistances connected in parallel. .The resistance unit as a whole will be so chosen with reference to the lamp with which it is to be used so that there will be a voltage drop from the source of supply to bring the line voltage down to the voltage at which the lamp is designed to operate. The two sections of resistances R1 and R: will be so chosen as to provide a sufllcient differential between them so that a current surge equal to or greater than the operating current of the lamp will occur when the circuit is closed by the starterin Fig. 3. It will be readily realized that theflvalues of the resistances R1 and R: will vary according to the different conditions under which the resistance unit is called upon to operate, but for illustrative purposes assuming a line voltage of substantially 115 voltsa'nd a 20 -watt lamp designed to operate at volts .440 MA current we will choose one resistance R1 at starter, the starter may be also utilizedwithin becomes suflicient'the bi-metal 2. will flex to shunt in the resistance R: so that these two may operate in parallel in the circuit. The bi-metal may be so chosen as to provide the desired time lag for the heating required. By the use of'this arrangement in many instances we may prevent blackening at the endof the lamp which might occur and does in some cases occur where a fluctuating discharge occurs before theelectrodes becomeheated sufliciently.

By the arrangement of unequal resistances in this --'manner the shunting of one. resistance across another willproduce a current and build up the ionization in the gaseous discharge tube until it becomes sufliciently dense to extend across the tube fromone electrode to the other and cause a glow dischargeto occur. v

The resistances may he very small and take up much less space than an inductance ballast which heretofore was frequently used in a circuit of this character. The resistancs may be made sumciently small to be incorporated in the envelope end of a gaseous discharge tube and when the-resistance is located within such tube the heat which it generates serves to raise the temperature of the tube that it -may burn brighter. In Fig. 2 we have illustrated a stem 25 of glass material which shows the resistance designated generally I as mounted in position on a stem for location within a gaseous discharge tube. The stem 28 has two lead-in wires 30 and 21 with spuds II and II also shown in the stem. The electrode I I is shown as positioned between lead-in 21 and the spud 2|, mresistance support ll comprising adisc with a plurality oi notches in its'edgeis mounted on the spud 29 and lead-in 30. The coiled resistances R1 and Ba are woven back and forth in the notches and are both connected to spud 2| atone end and'to the .lead-in so at the other end. A suitable shield 32 is provided over'the top of the resistors.

It will be readily apparent that the resistor designated generally Il may either be provided as a separate unit tobe substituted for the inductor now used in the circuit or it may be mounted on a stem press to be incorporated in the lamp itself, and thus require no outside connection and be much more simple for installation of the lamp. The non-inductive resistors are sufliciently inexpensive so that recovery when the lamp-is burned out is of no importance.

Although the lamp heretofore described may be utilized as a complete unit with a separate the lamp itself, and we have shown inFig. 6 a stem designated generally I having lead-in wires 30 and 31 and a spud ll provided in the stem. An electrode fllament II will be supported between the lead-in I. and the slid 38 while we may provide'a bi-metal 3| secured to the leadin 31 as by welding and so arrangedthat it nor- 400 ohms and theother resistance R2 at 250 ohms mally contacts spud II. The bi-metsl II is so arranged that when it becomes heated its end 40 will'sparate from spud 88 to break the circuit.

In operation the electrodes II and [2 become heated, and when heated sufliciently,'the tube will become lighted. This heating of the electrodes also heats the bi-metal 39 by reason of current passing therethrough and from the heat of the electrodes and causes the bi-metal to contract sufllciently so as to separate its end 40 from the spud 38 and thereby break the shunt circuit. The ionization of the gas in the tube for a glow discharge between the electrodes serves to keep the bi-metal contracted and the shunt circuit open.

By the use of our resistance, we are able to do away with the expensive part of the fluorescent lighting circuit as it at present exists in domestic installation; the resistance being of such a type that it may be made small also enables us to incorporate the resistance in the lamp itself, to also reduce installation cost and while carrying the matter of reducing installation cost still further we may incorporate the starter within the tube which starter operates difierently than the separate starter mentioned above in either the Dench or Hayes patent, as in our lamp the bimetal initially closes the circuit which opens and remains open during the operation of the gaseous discharge lamp.

We claim:

1. A gaseous electric discharge lampcomprising an envelope, electrodes and an ionizable medium therein, and unequal resistances within said envelope and connected in parallel in the lead to one of said electrodes for producing a current surge at the start of the lamp.

2. A gaseous electric discharge lamp comprising an envelope, electrodes and an ionizable medium therein, and unequal resistances within said envelope and connected in parallel in the line to one of said electrodes for producing a current surge at the start of the lamp, and a starter within said envelope to be in series with one of said electrodes.

3. A gaseous electric discharge lamp comprising an envelope, an ionizable medium within said envelope, a pair of stems extending into said envelope, an electrode supported by each stem, unequal resistances supported by one stem and con-, nected in parallel in the line to the electrode on said stem for producing a current surge.

4. A gaseous electric discharge lamp comprising an envelope, an ionizable medium within said envelope, a pair of steams extending into said envelope, anelectrode supported by each steam, unequal resistances supported by one stem and connected in parallel in the line to the electrode on said stem for producing a current surge, and a relay supported by the other stem within said envelope and in series with the electrode supporting said relay.

5. The combination with a source of electrical energy a load designed to operate at a'voltage below that of said source of energy, means tor causing a voltage drop in said line between said source and line comprising a resistance unit having therein unequal resistances connected in parallel, a shunt circuit across said load, andmeans for making and breaking said shunt circuit so arranged as to break said shunt circuit said circuit upon inoperation of said load.

7. The combination with a source of electrical energy a load designed to operate at a voltage below that of said source of'energy, means for causing a voltage drop in said line between said source and line comprising a resistance unit having therein unequal resistances connected in parallel, a shunt circuit across said load, and a gaseous electric relay for making and breaking said shunt circuit so arranged as to break said shunt circuit upon operation of said load and re-establish said circuit upon inoperation of said load.

8. In combination, a circuit having a source of electrical energy, a gaseous electric discharge lamp provided with a readily ionizable medium and having therein electrodes adapted to be heated to electron-emitting temperature, a resistance unit in said circuit comprising non-induction resistances in parallel, said resistances being chosen of such unequal values as to produce suflicient delay for the heating of the filament to proper electrode-emitting temperature and a current surge for the operation of said lamp, and a controlled shunt circuit across said lamp.

9. In combination, a circuit having a source of electrical energy, a gaseous electric discharge lamp designed to operate at less than that of the voltage of the electrical source and provided with a readily'ionizable medium and having therein electrodes adapted to be heated to electron-emitting temperature, a resistance unit in said circuit of such total value as to reduce the voltage of the electrical source to the voltage of I the lamp comprising non-induction resistances in parallel, said resistances being chosen of such unequal values as to produce sufflcient delay for the heating of the filament to proper electrodeemitting temperature and a current surge for the operation of said lamp, and a controlled shunt circuit across said lamp.

10. In combination, a circuit having a source of electrical energy, a gaseous electric discharge lamp provided with a readily ionizable medium and having therein electrodes adapted to be heated to electron-emitting temperature, a resistance unit in said circuit comprising non-induction resistances'in parallel, means to shunt one of said resistances across the other after a predetermined length of time, said resistances being chosen of such unequal values as to produce sufficient delay for the heating of the filament to proper electrode-emitting temperature and a current surge for the operation of said lamp, and

JOSEPH J. KNOUSE. RICHARD SJ. STONE.

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