US2347222A - Gaseous discharge lamp and starting mechanism therefor - Google Patents

Description

April 25, 1944. s E 2,347,222

GASEOUS DISCHARGE LAMP AND STARTING MECHANISM THEREFOR 7 Filed Jan. 23, 1941 Tic:,.2..

VOLTS 3 5. j B m m.

,5 i M /3/ M -11- INVENTOR Pm/P SIrZEA BY M/T M am w W r41) ATTORN EYS and starting mechanism therefor.

Patented Apr. 25, 1944 GASEOUS DISCHARGE LAMP AND STAETENG MECHANISM THEREFOR Philip Sitzer, Irvington, Sol Lamp Works Inc.,

tion of Delaware N. J., assignor to Tang Newark, N. .l., a cor orat Application January 23, 1941, Serial No. 375,556

20 Claims.

.to thermally operated circuits utilizing such This invention relates switches and control switches.

One object 01' the invention is a fluorescent lamp embodying a novel and improved starting circuit.

A further object of the invention is a novel and improved combined fluorescent or gaseous lamp and starting mechanism.

A further object of the invention is a novel and improved starting circuit for fluorescent and other gaseous discharge lamps.

A further object of the invention is a novel and improved thermally operated control switch.

A further object of the invention is a novel and improved thermally operated switch and circults controlled thereby.

Other objects of the invention will hereinafter appear.

For a better understanding of the invention reference may be had to the accompanying drawing forming a part oi this application wherein- Fig. 1 illustrates a fluorescent lamp and starting mechanism embodying the invention;

Fig. 2 is a diagram illustrating the voltage current characteristic of an element of the starting mechanism; and

Figs. 3 to 11 inclusive illustrate the utilization of a thermally'operated switch embodying the invention in other control circuits.

Referring to Figs. 1 and 2 of the drawing, the invention is illustrated as embodied in a fluorescent or gaseous discharge illumination device A conventional fluorescent or gaseous discharge envelope is indicated at I, having the conventional heating electrode filaments 2 in the opposite ends thereof. The numeral 3 indicates an alternating current supply line for the lamp tube l and the conventional inductive reactance (is illustrated as connected in series with the lamp 2 in order to limit the running current to a definite value.

In order to initiate the discharge between the electrodes 2 or to start the lamp a higher starting voltage is required than is required for running the lamp 'or-keeping it lighted after the arc discharge is once started. The heating filaments 2 are utilized to ionize the gas or gases in the tube I to facilitate the starting operation. This invention includes a resistance heater element M and a thermally operated element B, with the resistance element M connected across the line conductors 3 in series with the filaments 2 and with the thermally operated element 13 controlling the relatively movable contacts and 6 to temporarily short-circuit the resistance element M. The circuit of the resistance element M includes the conductors l and leading Irespectively to one end of the heating filaments 2, with the other ends or" the filaments connected with the line conductors A condenser 9 is connected across the contacts 5 and ii in order to minimize sparking and assist in the starting.

The resistance element M is composed of a material whose voltage-current characteristic curve is characterized by a rapid and out of proportion increase in current with. increase in voltage. This is shown graphically by the voltage vs. current curve in Figure 2 wherein it is observed that the slope of the curve is changed at each succes sive point which indicates that the change in cur rent is out of proportion to the change in volt age. This general characteristic is to he ex hibited by any of the materials lvi used this invention. It is also understood that the curve 0 Figure 2 is representative or a particular quality and varied or altered in uuant y and degree depend ing upon the type of ma iai used, the sine and shape, and the temperature which material M is allowed to attain as the ruin actors aifecting the curve. As stated above. however, the general characteristic of material he is to he such that the current flowing through the material M, due to an applied increasing voltage, increase at a rate greater than and out of proportion to the increase in voltage. Also, the greater the rate of current change with a certain. change in volt age, the more suited is the material M to the invention. The characteristic detailed above is uti lized in the fluorescent lamp or fluorescent lamp circuit of Figure l in the starting of the lamp, the marked rising characteristic of th currentvoltage curve being utilized to furnish the heat required to operate the thermally responsive element B when the line circuit is first closed. Thus, upon closure of the line circuit (the power line and switch being omitted for convenience in illustration) the full line voltage is applied to the inductive reactance the filaments and the resistance element M, and in some cases, this voltage is boosted for some types of fluorescent lamps by a step-up transformer control which is omitted for convenience in illustration; with the circuit thus closed and by proportion of voltages in a circuit of this kind (resistance of material M being comparatively very high) pracmaterial or" one melons and may tically the full line voltage is applied across re sistance M, as for one example, 165 volts, the current flow through the resistance element M becomes, comparatively, very large as indicated by the characteristic curve in Figure 2 with the result that the heat units dissipated by the resistance element are sufficient to operate the thermally responsive element B which is caused to bend in the direction indicated by the arrow to close the contacts and 6 and to short-circuit the resistance element M. Under this condition, the current flow in the circuit becomes very large, limited mainly by the reactance 6 and causing the filaments 2 to be heated. Simultaneously, the short-circuiting of the resistance M results in rapid cooling of the same due to the shunting of the current with the result that the thermally responsive element B after a suitable time delay, opens. The time delay in the opening of the element B is sufdciently long to allow proper heating of the filaments 2, and the starting or the discharge through the lamp tube i results from the high inductive surge voltage induced by the reactance it when the short-circuit current flow is interrupted by the opening of contacts 5 and 15. The startin is also aided by the heated condition of the filaments 2 which partially ionizes the gases in the lamp tube i.

If perchance the arc does not. strike at the first cycle of operation of the element B, a second cycle of operation of the element B will result in closure and after suitable time delay, opening of contacts 5 and 6 with the attendant heating of the filaments 2 during the closed period and inducing of a high voltage surge at the instant of opening, and repeated operations of the element B, until the lamp starts, will assure the starting of the lamp, although ordinarily only one closing and opening operation of the contacts ti and 6 is necessary to efitect this result. After the arc is struck and the lamp is operating, the current flow through the resistance M is so small as to render negligible the power which is constantly consumed thereby during the operation of the lamp, the voltage drop across the operating lamp (and, thereby, the voltage across resistor element M) being for the example of a conventional lamp taken above, about 120 volts. Thus for a material M whose current voltage characteristic would be illustrated by Figure 2 it can be seen that the current flow through the resistance material M while greater than 1% ma. at 165 volts is only 4 ma. at 120 volts, this making it relatively easy to prevent closure of contacts'5 and 6 at 120 volts when the lamp is operating and thereby assure of a properly functioning starting mechanism.

The resistance heater element M may be composed of any suitable material giving the desired current voltage characteristic, but preferably it is a carborundum or carborundum-like material or a material composed mainly of silicon carbide or silicon carbide and carbon combined with another material, as for example a material containing 75% of silicon carbon with around 25% iron pyrite or 25% galena or 25% zinc oxide. A material of the character described in Patent No. 1,822,742 may be used and particularly good results have been obtained with the use of a material known in the trade as Thyrite which comprises essentially silicon carbide, a conducting material such as carbon and a binder. It is understood, however, that although this is the at present preferred material, other materials having similar characteristics may be employed in the making of the resistance heater ele- -ment M.

The thermally responsive element 18 may be of any suitable thermally or heat responsive material as for example a bi-metallic strip which bends upon being subjected to heat.

The thermally controlled switch comprising the resistance heater element M and the thermally responsive element B-has other uses than that illustrated in Fig. 1, as for example shown in Figs. 3 to 11. I

Fig. 3 shows the utilization of this switch as a relay to control a circuit H by applying a controlling voltage at E2, the arrow indicating the direction of bending of the element B upon being heated by the resistance element M of the characteristics shown in Fig. 2. Fig. a shows a control similar to Fig. 3 with the control circuit normally open but in this case the element 13 assumes a substantially straight position in the cold'condition, and bends in a direction away iron: the heater or resistance material M.

" Figs. 5 and 6 are views of control circuits sim- Figs. 7 and 8 are circuits similar to the controls of Figs. 3 to 6, but here there are two controlled circuits the element 18 controlling two fixed contacts and one of the circuits being nor mally closed and the other one normally open, and by the word normally" meaning the cold condition.

Figs. 9 and 10 show the utilization of the thermally operated switch B, M in a circuit to be intermittently closed or flashed, the circuit to be thus controlled and operated being connected with the terminals l3.

Fig. 11 indicates the use of the switch B,M in a signal circuit to indicate an abnormal voltage applied to the terminals it, an indicating lamp it being connected in series with the switch which by its intermittent lighting by the intermittent closing of the switch B indicates the abnormal voltage.

Although the invention is illustrated in Fig. 1 as applied to an alternating current system and lamp, it is understood that the principle is applicable to direct current supply circuits and lamps, Although the general arrangement of the invention as described above is desired at resent, it is to be understood that other modifications thereof may be made without. departing from the spirit and the scope of the appended claims.

I claim:

l. The combination of a gaseous discharge device with a starting and operating circuit therefor comprising an envelope with heating electrodes therein, a resistance heating element connected in series with said electrodes and having a voltage-current characteristic characterized by the rapid and out-of-proportion increase in amperage with increase in voltage above the range of the operating voltage of the device, and a thermally responsive element associated with said resistance heating element and operated thereby to establish a moinentary short circuit therearound.

2. A starting circuit for a gaseous discharge lamp and the like comprising heating filament discharge electrodes connected on one side respectively with supply line conductors, a resistance heating element connected with the other sides of the electrodes so as to be in series therewith across the line and having a currentvoltage characteristic characterized by a rapid and out-of-proportion increase in amperage flow upon increase in voltage above the operating voltage of the lamp, and a thermally responsive element associated with said heat resistant element and adapted to momentarily short-circuit the same in response to the heat dissipation arising from the large flow of current through the resistance element at starting.

3. A starting mechanism for gaseous discharge lamps and the like comprising a resistance heater element connected in multiple with the lamp and having a current-voltage characteristic characterized by a rapid and out-oi-proportion increase in current flow at voltages above the operating voltage of the lamp, and a thermally responsive element associated with said heater element and operative to momentarily short-circuit the same upon a predetermined current flow therethro lgh.

4. The combination of a gaseous discharge device with a starting and operating circuit therefor comprising an envelope with heating electrodes therein, a resistance heating element connected in series with said electrodes and having a voltagecurrent characteristic characterized by the rapid and out-of-proportion increase in amperage with increase in voltage above the range of the operating voltage of the device, and a thermally responsive element associated with said resistance heating element and operated thereby to establish a momentary short circuit there-around, the resistance heater element containing silicon carbide as the predominating constituent.

5. A starting circuit for a gaseous discharge lamp and the like comprising heating filament discharge electrodes connected on one side respectively with supply line conductors, a resistance heating element connected with the other sides of the electrodes so as to be in series therement at starting, the resistance element containing silicon carbide as the predominating constituent.

6. A starting mechanism for gaseous discharge lamps and the like comprising a resistance heater element connected in multiple with the lamp and having a current voltage characteristic characterized by a rapid and out-oI-proportion increase in current flow at voltages above the operating voltage of the lamp, and a thermally responsive element associated with said heater element and operative to momentarily short-circuit the same upon a predetermined current flow therethrough, the resistance element containing silicon carbide as the predominating constituent.

'7. A starting mechanism for gaseous discharge lamps and the like comprising a resistance heater element connected in multiple with the lamp and having a current voltage characteristic characterized by a rapid and out-oi-proportion increase in current flow at voltages above the operating voltage of the lamp, and a thermally responsive element associated with said heater element and operative to momentarily short-circuit the same upon a predetermined current flow therethrough, the resistance heater element being of Thyrite.

8. A starting mechanism for gaseous discharge lamps and the like comprising a resistance heater element connected in multiple with the lamp having a current voltage characteristiccharacterized by a rapid and out-oi-proportion increase in current flow at voltages above the operating voltage of the lamp, and a thermall; r sponsive element associated with said heater element and operative to momentarily short-circuit the same upona predetermined current flow therethrough, the resistance heater element being formed of carborundum.

9. A starting mechanism for gaseous discharge lamps and the like comprising a resistance heater element connected in multiple with the lamp and having a current voltage characteristic characterized by a rapid and out-oiproportion increase in current flow at voltages above the operating voltage of the lamp, and a thermally responsive element associated with said heater element and operative to momentarily short-circuit the same upon a predetermined current flow therethrough, the resistance heater element containing silicon carbide and other constituents, the silicon carbide being the predominating constituent.

10. A starting mechanism for gaseous discharge lamps and the like comprising a resistance heater element connected in multiple with the lamp and having a current voltage characteristic characterized by a rapid and out-of-proportion increase in current flow at voltages above the operating voltage of the lamp, and a thermally responsive element associated with said heater element and operative to momentarily short -circuit the same upon a predetermined current flow therethrough, the resistance heater clement containing silicon carbide and carbon, the silicon carbide being the predominating constituent.

11. A control circuit comprising a resistance element having a voltage-current characteristic characterized by a gradual increase in'amperage up to from So to ice volts and by more rapid and out-oi-proportion rise in current at higher voltages, and a control element responsive to the rapid and out-of-proportion increase in amperage for momentarily establishing a short circuit around the resistance element.

12. A control circuit comprising a resistance element having a voltage -cim'ent characteristic characterized by a gradual increase in amperage up to from so to we volts and by a more rapid and out-of-proporticn rise in current at higher voltages, and a control element responsive to the rapid and out-of-proportion increase in amperage for momentarily establishhig a short circuit around the resistance element, the resistance heater element being composed of carborundum. 13. A control circuit comprising a resistance element having a current-voltage characteristic characterized by a rapid and out of-proportion rise in current flow at predetermined voltages, a control element responsive to the rapid and out of-proportion increase in amperage i'or momentarily establishing a short circuit around the resistance element.

14. A control circuit comprising a resistance heater element having a current-voltage characteristic characterized by a rapid and outof-pro portion rise of current at predetermined voltages, and a thermally controlled element operated by the heat dissipated from said heat resistor for momentarily short-circuiting the resistance element.

15. A starting mechanism for fluorescent lamps comprising a resistance heater element having a current-voltage characteristic characterized by a gradual increase in amperage up to from 80 to 100 volts and by a more rapid and out-of-proportion increase in currentfiow at higher voltages and a thermally responsive element associated Withthe heater element and operated to momentarily short-circuit the same upon a predetermined current flow therethrough.

16. A starting circuit for a gaseous discharge lamp and the like comprising heating filament discharge electrodes connected on one side respectively with supply line conductors, a resistance heating element connected with the other sides of the electrodes so as to be in series therewith across the line and having a current-voltage characteristic characterized by a rapid and out of-proportion increase in amperage flow upon increase in voltage above the operating voltage of the lamp, a reactance in series with the discharge lamp, and a thermally responsive element associated with said heat resistant element and adapted to momentarily short-circuit the same in response to the heat dissipation arising from the large how of current through the resistance element at starting.

17. A starting mechanism for gaseous discharge lamps and the like having heater filament discharge electrodes therein, comprising a resistance heating element connected in series at starting with said electrodes and having a current voltagev characteristic characterized by a rapid and outofiproportion increase in amperage flow upon increase in voltage, a reactance in series with the discharge lamp and a thermally responsive ele ment associated with said heat resistance element and adapted to momentarily short-circuit the same in response to the heat dissipation arising from the large flow of current through the resistance element at starting whereby upon the initial closure of the circuit sumclent current flows through the resistance heating element to operate the thermally responsive element to cause the me to momentarily short-circuit the heater elet with increased heating of the discharge odes upon such short-circuiting operation a with the prompt opening of the short-circuit upon the re-cooling oi the heat resistance heating element and the application of the starting voltage to the lamp.

18. A circuit for a gaseous discharge lamp and the like comprising heating filament discharge electrodes connected on one side respectively with supply line conductors, a resistance element connected with the other sides of the electrodes so as to be in series therewith across the line, said resistance element having a current voltage characteristic characterized by a gradual increase in current flow up to from to volts and a rapid and out-of-proportion increase in amperage flow upon increase in voltage above 100 volts, a reactance in series with the discharge lamp, and a control element responsive to the rapid and out-of-proportion increase in amperage for momentarily short-circuiting said resistance element at starting.

19. The combination of a gaseous discharge device with a starting and operating circuit there for comprising an envelope with heating electrodes therein,'a resistance element connected in series with said electrodes and having a voltagecurrent characteristic characterized by a gradual increase in amperage up to from 80 to 100 volts and by a rapid and out-of-proportion increase in amperage at voltages above 100 volts and a control element responsive to the rapid and out-0fproportion increase in amperage for momentarily establishing a short-circuit around the resistance element.

20. The combination of a gaseous discharge device with a starting and operating circuit therefor comprising an envelope with heating electrodes therein, a resistance element connected in series with said electrodes and having a voltagecurrent characteristic characterized by a gradual increase in amperage up to from 80 to 100 volts and by a more rapid and out-of-proportion increase in amperage at voltages above 100 volts and a thermally responsive element responsive to heat generated by the rapid and out-oi-proportion increase in current for momentarily establishing a short-circuit around the resistance element.

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