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Publication numberUS3758824 A
Publication typeGrant
Publication dateSep 11, 1973
Filing dateJul 23, 1970
Priority dateJul 23, 1970
Publication numberUS 3758824 A, US 3758824A, US-A-3758824, US3758824 A, US3758824A
InventorsWarneke C
Original AssigneeSherwin Williams Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Amplification of induced radiation and means for attaining the same
US 3758824 A
Abstract
Production of, high intensity, stroboscopic radiation rich in ultraviolet rays, by energizing gaseous discharge lamps, containing a noble gas or gases and metallic vapor, with a modified A.C. wave, derived from a conventional source of sinusoidal alternating current power, and characterized by sharp peaks of short duration of the conventional power source from which the sharply peaked lamp-energizing wave is derived, the disclosure also embracing circuitry energized from a convention A.C. power source for producing the multiplied frequency, sharply peaked lamp-energizing wave, including a resonant circuit adjusted for slightly off resonance operation.
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Description  (OCR text may contain errors)

United States Patent 91 Warneke 1 Sept.'1l, 1973 AMPLlFlCAT-ION OF INDUCED RADIATION AND MEANS FOR ATTAINING THE SAME [75] inventor: Car1J.Warneke,-Chicago,lll.

[73] Assignee: The Sherwin-Williams Company,

Cleveland, Ohio [22] Filed: July 23, 1970 [21] Appl. No.: 64,057

'Related U.S. Application Data [63] Continuation of Ser. No. 691,455, Dec. 18, 1967,

abandoned.

[52] U.S. Cl 315/246, 315/276, 315/278, 315/282 [51] Int. Cl. H051) 41/16 [58] Field of. Search 315/276, 277, 278, 315/279, 282, 246

[56] References Cited UNITED STATES PATENTS I 6/1944 Boucher et a1. 315/278 X Primary Examiner-Nathan Kaufman Attorney-Johnston, Root, OKeeffe, Keil, Thompson & Shurtleff [57] 7 ABSTRACT Production of, high intensity, stroboscopic radiation rich in ultraviolet rays, by energizing gaseous discharge lamps, containing a noble gas or gases and metallic vapor, with a modified A.C. wave, derived from a conventional source of sinusoidal alternating current power, and characterized by sharp peaks of short duration of the conventional power source from which the sharply peaked lamp-energizing wave is derived, the disclosure also embracing circuitry energized from a convention AC. power source for producing the multiplied frequency, sharply peaked lamp-energizing wave, including a resonant circuit adjusted for slightly off resonance operation.

8 Claims, 9 Drawing Figures PATENTEB SEP] 1 I973 SHEEI 1 BF 3 dd m m:

INVENTOR: CARL J. WARNEKE PATENTEDSEPI 1 I915 3.7580824 SHEET 3 OF 3 FIGS) INVENTOR: CARL J. WARNEKE Y (magaq qww flvd m ATT'YS AMPLIFICATION OF INDUCED RADIATION AND MEANS FOR ATTAINING THE SAME This application is a continuation of U.S. application, Ser. No. 691,455 filed Dec. 18', 1967 now abandoned.

The present invention relates in general to the production of artificial light, and has more particular reference to the generation of particularly intense radiation that is especially useful in the stimulation of chemical action by incident light rays, as well as for other purposes including the stimulation of laser irradiation.

An important'object of the present invention is to provide means for and method of producing high intensity light peaking'at high'frequency-and at short time infernals, the light being produced in gaseous discharge lamps energized in novel fashion by the application thereto of an alternating current pulse having unconventionally abrupt, high peaks; a further object being to provide a translation circuit or peaked wave generator for producing the desired abruptly peaked current pulse, when excited by conventional sinusoidal A.C. energy, the current pulse being characterized by momentary high peaks of sharply defined character.

Briefly stated, the present invention may be practiced, for light production, by electrically energizing a gaseous conduction lamp or lamps from a conventional source of A.C. electricalenergy, such as the conventional I10, 220 or 440 volt, 60 cycle A.C. electrical power supply line, in'which voltage and current fluctuate more or less sinusoidally, lamp energizing power being applied through translation circuitry embodying transformers, capacitors and reactors arranged to produce lamp exciting energy having multiplied frequency and sharply peaked wave form.

Another object of the invention is to provide a novel peaking transformer in the translation circuit, said transformer having an autowinding and associated capacitance for producing the desired electrical phenomenaembodied in the wave, that is to say the sharp high energy peaking function; a further object being to provide a peaking transformer, in the translation circuitry, haivng a core comprising magnetic material such as ceramic ferrite materials or alloys, including iron, nickel, cobalt, titanium or molybdenum; a further object being to correlate the thickness of core laminations, or of particle size of the magneticmaterial in unlaminated cores, and the dimension of the air gap between core stacks with appropriately adjusted capacitance, in parallel with the autowindings of the peaking transformer, to control the frequency of peaks obtained per second,

as well as the duration of the peaked portions of the.

pulses, and to reduce current and hysteresis losses to a minimum.

Another important object is to employ the magnetic and electrical factors attained by the combination of the special transformer core material and the size of the air gap between core stacks, in the magnetic circuit of the transformer, in conjunction with properly adjusted capacitance in the translation circuit, to produce a sharply peaking electrical discharge in a gaseous conduction lamp. In essence, the translation circuitry is arranged to produce a lamp exciting current pulse, which peaks the electrons or ionised space charges, in the lamp, into a discharge of substantially shorter time duration and higher peak ampere output than would otherwise be the case if the discharge were produced in response to conventional sinusoidal energy wave excitation. The conventional sine wave form is thus converted into a sharply peaked pulse output, produced by the wave peaking circuitry. When delivered to a lamp or lamps to be energized the peaked pulse produces high intensity flashes of short duration in the lamp.

An important object of the present invention is to actuate a gaseous vapor discharge lamp by peaking the electrons or space charges therein to produce discharges, in the lamp, at high frequency, correspondingly shorter time duration of discharge, and at higher peak energy than is possible when a conventional A.C. electrical energy wave is applied to drive the discharge lamp.

Numerous other important objects, advantages and inherent functions of the invention will become apparent as the same is more fully understood from the following description, which, taken in conjunction with the accompanying drawings discloses preferred embodiments of the invention.

FIGS. 1 and 2 are diagrammatic views of gaseous conduction lamp energizing systems embodying the present invention;

FIG. 3 is a graphical dashed line showing of a conventional, substantially sinusoidal, current wave of the sort commonly employed for driving gaseous conduction lamps, and a superposed solid line current wave graph illustrating the output voltage in lamp energizing systems operated in accordance with the present invention;

FIG. 4 is a perspective view of a primary transformer used in the systems shown in FIGS. 1 and 2;

FIG. 5 is a perspective view of a peaking transformer provided with air gaps in its core, in accordance with the present invention;

FIG. 6 is a sectional view taken substantially along the lines 6-6 in FIG. 5;

FIG. 7 is a sectional view taken substantially along the lines 7-7 in FIGQ6; FIG. 8 is a sectional view showing a magnetic shunt having air gaps of variable width that may be provided in primary power supply transformers in accordance with the present invention; and

FIG. 9 is a diagrammatic view of a lamp energizing system embodying the present invention, including novel regulating means for controlling energizing power supplied to the system as a function of fluctuations in energy flow in the system.

To illustrate the invention, the drawings show electrical translation systems 11 for applying sharply peaked high energy waves to appropriate electrical loads 13, such as and including the conventional gaseous vapor discharge lamp means, to energize the same for the production of radiation of high intensity, the translation system being energized from a suitable A.C. electrical power source.

Gaseous conduction lamps, of the character mentioned, are conventionally energized for operation by the application, between the lamp electrodes, of conventional -220 volt A.C. electricity. The present invention, however, teaches that, by energizing gaseous conduction lamps with electrical energy having wave forms of abruptly peaked character, radiation of sub stantially altered character and of unexpectedly high intensity, is produced, such high intensity radiation being especially useful in promoting desired photochemical reactions.

The translation system 11 through which the discharge lamps are energized, in accordance with the teachings of the present invention, is driven from a conventional A.C. electrical power source; and it will be apparent that, by suitable design modifications, the system may be operated at any desired supply line voltage and frequency available in the area where the system is set up for use.

Essentially identical translation systems 11 for practicing the invention are shown in FIGS. 1 and 2, the same, respectively, being adapted to deliver energy of the order of 3,500 watts to power a load shown as a single high intensity lamp element L, in FIG. 1, and to deliver energy for driving a somwhat lesser load, of the order of 2,200 watts, such as may be provided by the several series connected lamps La, Lb, Lc, Ld, shown in FIG. 2. The translation systems 11 both comprise transformers, capacitors and reactors, including a peaking transformer 17, connected with the load 13 and through which high potential lamp energizing power, of sharply peaked wave form, may be delivered to the load.

The peaking transformer 17, in each case, is energized through a step-up, constant-current, currentlimiting transformer 19, of the sort commonly called a high reactance or ballast type, self-regulating transformer. The transformer 19 has a secondary or output winding 21, electrically connected to energize the peaking transformer 17, and a primary winding 23, adapted for connection with a suitable source of energizing power, such as the 220 volt A.C. power source 15. In the FIG. 1 arrangement, the primary winding 23 of transformer 19 is energized through a self-regulating saturable reactor or transductor 27, adapted to automatically balance and compensate for variations in line voltage. In this connection, the saturable core reactor 27 employs relatively low direct current excitation to control the flow of a much larger quantity of alternating current energy through the device. To this end, the reactor may comprise a magnetic core having three legs, A.C. windings 29, 29, being mounted on the outer legs of the core and being electrically connected in reversely polarized parallelism in a series circuit including the power source and the primary winding 23 of the transformer 19.

A saturating winding 31 may be mounted on the central leg of the core and electrically connected with a suitable source of energizing power such as the DC.

- energy source 33, preferably through adjustable means,

such as a rheostat 35 for setting the voltage applied at theopposite ends of the saturating winding 31, between zero and a voltage of the order of 15 volts. The A.C. coils 29, 29', on the outer legs of the core, may be connected either in series or parallel relationship, so that the magnetic flux associated with the windings 29 and 29' passes through the outside legs of the core and also through the center leg which carries the saturating winding.

The saturating winding 31 serves to set up a core saturating flux which varies as a function of DC current flow in the winding 31. The effective magnetic permeability of the outer legs of the core varies inversely with current flow in the winding 31. The reactance of the A.C. coils 29, 29 varies inversely with D.C. saturation as does also the total impedance in the A.C. circuit controlled by the reactor. Thus, by increasing saturation of the reactor 27, the electrical current delivered to the primary winding '23 of the transformer 19 may be automatically controlled.

Alternately, as shown in FIG. 2 of the drawings, energizing power from the source 15 may be delivered to the primary winding 23 of the transformer 19, through an adjustable transformer or powerstat 35, to thereby regulate the voltage at which energy is delivered to the primary winding 23.

The primary transformers 19, in each case, may comprise a three-legged core, shown in dashed lines in FIGS. 1 and 2 of the drawings, having the secondary and primary windings 21 and 23 applied in position encircling the middle leg of the core, the windings being preferably arranged in coaxially spaced apart relationship at the opposite ends of the medial core leg. The power output level of the driving transformers 19 may arrange between the order of several hundred kilowatts, in single or multiple units. Variations in the constituent material employed in the transformer core and the geometry type and spacing of the core material will of course depend upon final requirements and the design of production units.

The present invention contemplates a control system which provides constant voltage and current flow in the secondary or output winding 21 of the driving transformer 19. This control system is built into the transfonner by providing a magnetic shunting connection, in the core 37 between each of the outer legs 41 and the central leg 39, opposite the space between the facing adjacent ends of the secondary and primary transformer windings 21 and 23, control coils 45 being applied in position encircling the shunt core portions 43 and connected in series with the A.C. windings 129, 129' of a saturable core reactor or transductor 27', which may be a duplicate of the reactor 27. The transductor 27', as shown, has a saturating winding 131 preferably through an adjustable resistor 135 or other means for varying the flow of energizing power to the saturating winding 131. The shunt core portions 43, as shown in FIG. 8 of the drawings, may be secured in position in any preferred fashion, as by means of wedging shims44 of nonmagnetic material applied at the opposite ends of the shunt core portions or legs 43. In order to provide for adjusting the width of the air gaps, at the opposite ends of the legs 43, said ends may be slanted or inclined, as shown, so as to vary the effective width of the air gaps by adjusting the alinement of the leg elements 43 transversely of the core members 39 and 41, between which they are mounted.

The shunt paths 43, in the transformer 19, carry lines of magnetic force derived from the main flux set up in the core by the primary winding 23, thereby by-passing the secondary winding 21 and reducing the amount of magnetic flux which otherwise would be applied to the secondary winding 21. If the current in the secondary winding 21 increases unduly, a corresponding amount of current is generated in the windings 45 and transmitted thence to the windings 129, 129' of the transductor. As these turns 131 become D.C. saturated, current flow is allowed from the primary 23 to the secondary 21. As saturation drops off some flow feeds back to the primary, thereby accomplishing the desired control.

The secondary or output winding 21, of the transformer 19 is connected in series with the input winding of the peaking transformer, said secondary winding 21 being preferably provided with a grounded center tap 47.

The peaking transformer 17, in each embodiment, comprises a generally ring-shaped core 49 of rectangular sectional configuration having spaced apart parallel flat side portions 51' and more or less curved portions 53 interconnecting the opposite adjacent ends of the portions 51. The transformer core 49 may be fabricated by winding a thin continuous sheet metal strip, of desired magnetic material having appropriate width, upon a suitable form, to provide a transformer core of desired thickness containing an appropriate number of layers of the constituent sheet metal strip, the width of the core being that of the constituent sheet metal strip of which it is formed. The type of steel employed in the core lamination strip material determines the rate of magnetic flux change in the core, which, in turn, effects the speed at which the discharge takes place in the lamp load 13.

The transformer 17 may also comprise windings 55, including coil sections 57 and 59 interconnected in series. The coil section 57 may comprise 180 turns, more or less, of number 9 square conductor wire, the section 59 comprising 725 turns, more or less, of number 12 round conductor wire. The adjacent ends of the sections may be electrically connected together and with a connection tap or lead 61. The coil section 59, if desired, may be provided with spaced connections taps 63 spaced from the tap 69, for the connection of overload safety devices or other optional components.

The sections 57 and 59 may be applied in position encircling a generally rectangular sleeve of insulating material 65 sized to snugly embrace and enclose the side 51 of the core 49 on which the windings 55 are to be mounted. In forming the windings 55, the insulating sleeve 65 may be supported on a suitable mandrel, and the conductor material of the inner coil section 57 may be wound into position upon and around the sleeve 65 until the desired number of turns have been applied. The connection tap 61 and the conductor material of which the winding section 59 is to be formed may then be electrically interconnected with the outer end of the inner coil section 57, whereupon the constituent conductor material of the outer section 59 maybe wound into place in positioncovering and enclosing the previously wound coil section 57, the taps 61 and 63, if applied, being connected at appropriate locations in the outer coil section 59. Connection leads 67 and 69, of course, are provided at the starting end of the coil section 57 and at the finishing end of the section 59.

In order to mount the transformer windings 55, the core 49 may be severed, as by sawing through its flat side portions 51 at' or adjacent the junctions thereof with an end portion 53. if desired, clamps 73 may be applied to the end portions 53 in order to hold the core sections during the cutting operation. The clamps 73, at each end of the core, may comprise inner and outer clamping plates 75, 75', sized to extend across the inner and outer faces of the end portions 53, the plates 75 and 75 having opposite ends projecting outwardly of the opposite sides of the core. Clamping bolts or screws 77 extending through the outwardly projecting ends of the plates 75 and 75' may be employed to clamp the same together upon the ends of the core,

vAfter an end portion 53 has thus been severed from the core 49, the insulating sleeve 65 and the windings 57 and 59 thereon may be assembled on one of the flat side portions 51, and the severed end portion 53 may be mounted in position with its cut surfaces in abutting relationship with the cut surfaces of the core portions 51, thereby reconstituting the core 49 as a generally ring-shaped element with an air gap 79 extending transversely across each of the flat side portions 51, along the cutting plane 71. These air gaps 79 play an important part in producing the sharply peaked character of the current wave applied upon the load 13 by the peaking transformer.

The molecular structure of the core of the transformer becomes rearranged during each half cycle of applied current. At high frequency, the reluctance of the magnetic circuit interferes with and resists such rearrangement. As a consequence, the establishment of magnetic flux in the core becomes increasingly difficult and is retarded, or slowed, so that the desired peaking tends to occur at slower speed. By providing air gaps 79, however, the magnetic flux is allowed greater reversing freedom, during alternate half cycles of applied energizing power, so that the current peaks may be produced at optimum speed, limited only by the hysteresis characteristics of the core material.

ln the connection, a layer preferably of mica or other non-magnetic material is preferably interposed in the gaps 79 in order to assure separation of the facing surfaces of the core portions at the gaps. The widths of the gaps are of the order of a few thousandths of an inch, as for example 0.007 inch; and the gap widthmay be adjusted to obtain a desired peaking effect. Generally speaking, the wider the gap, the lower the inductive reactance of the transformer and the higher is the peaking effect, within limits, since an abnormally wide gap will reduce inductive reactance to a level where peaking becomes inefficient and unstable. If the gap is made too large, the necessary energizing force, required to establish a'desired flux density in the core, becomes excessive, so tnat efficiency is impaired. Thus, it is possible, by empirical trial and error methods, or by mathematical computation, to provide a particular transformer with gaps 79 adjusted to produce an energy wave having desired peaking characteristics for the operation of a particular load. This may be accomplished by applying an appropriate thickness of mica in the gaps 79 and by then drawing the core parts together on opposite sides of the gaps to the extent required to produce gaps of desiredwidth, as by applying one or more binding straps 81, as of steel, around the periphery of the core and by tightening the strap or straps to the desired extent, by means of strap tightening screws 83. Where binding straps 81 are. employed, the clamp structures 73 may be discarded.

It may be desirable to provide readily operable means for adjusting the width of the gaps 79, as will, in order to condition a particular transformer as an energy supply source for a selected load, that is to say, to match the peaking transformer to its load. This may be readily accomplished by providing screw threaded means operable to precisely determine the spacement of the core portions on opposite sides of the gaps 79. To this end, as shown more particularly in FIGS. 6 and 7, adjusting screws 85 extending between the clamps 73, and more particularly the clamp plates at the opposite ends of the core, may be employed to precisely adjust the width of the gaps 79.

One end of the secondary winding 21 of the step up transformer 19 may be electrically connected directly with the tap 61 at the junction of the coil sections 57 and 59 of the peaking transformer, the opposite end of said secondary winding being electrically connected,-

through a preferably adjustable condenser 87, with the outer coil section 59 of the peaking transformer, remote from the connection tap 61, as at the outer end of the coil section, at the lead 69, or at a selected one of the connection taps 63. A preferably adjustable condenser 89 may be interconnected between the connection tap 61 and whichever of the leads 63 or 69 may be employed in connecting the output winding 21 of the primary transformer 19 with the coil section 59.

The load 13 may be connected with the windings of the peaking transformer by electrically connecting the opposite sides of the load with the opposite ends of the transformer winding 55, that is to say, with the starting end of the coil section 57 and the. finishing end of the primary and secondary windings. The desired electrical phenomena, requires the use of core laminations of special types and thicknesses. Suitable types of core material include ferrite ceramic materials and fero alloys, including the alloys of iron with nickel, cobalt, titanium and molybdenum. The thickness of the core laminations and the size of the air gaps 79 between the laminated stacks of the core, in conjunction with appropriate capacitance connected in parallel with the autowinding of the peaking transformer, controls the phase angle, as well as the steepness of the pulses, current and hysteresis losses being reduced to a minimum.

The magnetic and electrical factors obtained through the combination of special core laminations and the dimensions of the air gaps'79 between the core portions or lamination stacks, in conjunction with appropriate capacitance values in circuit with the windings of the peaking transformer, provides an amplification effect, which results in a discharge in the lamp means 13. In essence, the peaking transformer and associated condensers attain a discharge of substantially shorter time duration and higher peak ampere output, than when discharge lamps are energized in conventional fashion by means of AC. electrical energy fluctuating sinusoidally. The conventional sine wave form is thus altered to provide a sharply peaked pulse form of energy, produced by the peaking action attained in the operation of the peaking transformer. When applied upon gaseous discharge lamps such peaked pulse form of energy results in the production of light flashes of exceedingly short duration and high intensity.

By way of example, in the embodiment shown in FIG. 1, the peaking transformer is used to power a single large 3,500 watt gaseous conduction metallic vapor lamp. The output winding 21 of the driving transformer 19 is connected in series with a 40 mfg. capacitance 87. The core laminations of the peaking transformer may comprise from 2 to 12 mil gauge, oriented silicon steel, in which all crystals are substantially parallel and extend in-the same direction. Thinner core laminations, of course, may also be employed, depending upon desired flash duration and hysteresis loss. The capacitance 89 of the circuit controlling the number of peaks and amplitude is connected in parallel with the auto- 8 winding 59 of the transformer and may vary within a range of the order of 5 through 20 mfd. Energy pulsations delivered for the operation of the lamp L comprise peaks of approximately 350-400 amperes during intervals having duration of the order of 0.35 to 0.4 milliseconds.

In the FIG. 2 embodiment, the load consists of four, series connected conduction lamps, each rated at 550 watts, making a total load of 2,200 watts. The series connected capacitance 87 in this case may comprise a 60 mfd. capacitor, while the parallel connected capacitor 89 may have a rating of 3-10 mfd. The peaking transformer has an oriented silicon steel core with 22 mil gauge laminations. The pulses delivered to the lamps have peak amperage of the order of -200 during intervals having duration of the order of 0.4 milliseconds.

The capacitors should have minimal loss angle and in order to promote rapid discharge. The combination of the autowinding 59 and the condenser 89 forms a resonant circuit in which the capacitance is adjusted or timed to a position short of or off resonance, in order to obtain wave peaks of desired altitude limited to the extent to prevent the load from being over energized, because, if the circuit were to be operated precisely at resonance, the energy supplied to the load might become excessive and result in the destruction of the lamps which form the load.

The peaking phenomena is illustrated in FIG. 3, in which a conventional 60 cycle sinusoidal energizing current wave is depicted as a dashed line, in which one complete wave cycle takes place in one-sixtieth of a second, or 16.7 milliseconds, I20 alternating peaks being produced per second. As the positive half cycle of energizing power is applied, the capacitors 87, 89 become charged up, and also the iron of transformer 17 becomes saturated or .magnetically stressed and strained. During this interval, the gas and vapors in the lamp become ionized and able to support current flow, which occurs when the energy wave approaches its positive peak. Thereafter, the energy stored in the capacitors and peaking transformer is discharged into the lamp to form an arc therein, thus producing a burst of light principally in the ultra violet region of the spectrum. This discharge takes place almost instantly, as indicated by the almost vertical solid line traces in the graph FIG. 3. The discharge carries onin'to the negative half cycle, because of the electromagnet inertia in the peaking circuitry, thereby creating the negative energy peak Pn immediately following the positive peak Pp, during the terminal phase of the energizing half cy cle. The air gaps 79 flatten and suppress, indeed substantially entirely eliminate the ripple 'Pr, shown in FIG. 3, which tends to occur between the negative pulse Pn and the next succeeding positive Pp. The circuit containing the capacitance 89 can double the number of peaks in the energy wave to 240 peaks per second, of shorter time duration and higher current intensity. The electrical power which activates the lamp is thus delivered in high intensity peaks of very short duration. As a consequence, the arcstream ionization in the lamp, which, with proper lamp filling provides the high 2,537 Angstrom unit ultra violet component of emitted light, is coherently amplified as a pulse function. It can be mathematically determined that the lamp is activated during an aggregate energized period of the order of 1.6 milliseconds or during four peaks occurring during a total elapsed time interval of 16.7 milliseconds, that is to say, the lamp emits radiation during only about one-tenth or less of the interval of operation.

A preferred embodiment of the translation system 11 of the present application is shown diagramatically in FIG. 9 of the drawings, in which the load comprises eight gaseous conduction lamps 13', connected in series, with an adjustable capacitor connected in parallel with each lamp. The peaking transformer 17' is provided with an auxiliary winding or coil 60, inductively coupled with the core 49 of the transformer as on the core leg 51', other than the leg 51 with which the transformer windings 55 are coupled.

The primary and secondary windings 23' and 21 of the current limiting power supply transformer 19' are inductively coupled, respectively, with the spaced outer legs 41' of the transformer core, rather than with a central leg, as in the corresponding transformers 19, employed in the FIG. 1 and FIG. 2 embodiments. The legs 41', of course, are connected between spaced core" members 42' which extend between the corresponding ends of the legs, to hold the same in spaced relation and complete the closed magnetic core circuit.

The secondary windings 21', also, may and preferably do comprise a plurality of separate or sections segments 8-1, 8-2, 8-3 and 8-4, which may be connected each to energize a separate peaking transformer circuit and its load. The several secondary winding sections, however, are shown connected in series to activate a single peaking transformer circuit and its load.

- As in the FIG. 1. and FIG. 2 embodiments, the current limiting transformer 19, shown in FIG. 9, is provided with power supply flux shunt path means comprising a bar or leg 43' of paramagnetic material disposed in the core between and parallel with the legs 41', which carry the primary and-secondary windings 23 and 21', to by-pass some of the magnetic flux induced in the core by the primary winding 23 and prevent it from reaching the secondary'windings. The shunt path bar or leg 43 may be secured in position between the core members 42', in any preferred fashion, as by means of wedging shims 44'- of non-magnetic material applied between the core members 42 and the ends of the shunt leg, to determine the width of the effective air gap or gaps at the opposite'ends of the shunt leg, as heretofore described in connection with the shunt paths provided in the FIG. 1 and FIG. 2 embodiments. A shunt winding 45' is inductively coupled with the flux by-pass leg 43.

The core of the transformer 19' may be and preferably is provided with an auxiliary flux by-pass path 46, by extending the ends of the core members'42' radially outwardly of one of the core legs 41, to form outstanding by-pass fingers 48'. The flux by-pass path 46 may include an armature 50' comprising a bar of paramagnetic material having opposite ends overlying the outer ends of the by-pass fingers 48 and forming air gaps 52' of desired width between the armature element 50' and said fingers 48. The auxiliary by-pass 46 serves as a regulating flux shunt. Under normal operating conditions, the phase of current delivered to the peaking transformer 17, from the secondary winding 21 of the power supply transformer 19', during the terminal portions of each energizing power half cycle, will lag due to the'discharge of condensers in circuit with the windings of the peaking transformer. Such lagging phase produces a counter electro-motive force (emf) in the secondary windings of the transformer 19 and a magnetic counter force in the transformer core 37', thereby increasing flux through the shunt 43', thus tending to overheat the same, due to shunt oversaturation, when the primary winding 23' becomes energized at the start of the successive energy half cycle. At such time, the auxiliary shunt 46' becomes effective to drain excessive flux from the by-pass shunt 43'. As a consequence, the spacement of the shunt member 50' from the fingers 48' should be adjusted to prevent undesirable overheating of the shunt means 43, which will depend upon the characteristics of the transformers. If desired, adjusting means 54', such as a manually operable screw, may be provided for adjusting the by-pass at any time; or the desired adjustment may be determined for a specific embodiment by applying spacers, of mica or other non-magnetic material, having appropriate thickness in the air gaps 52' and then clamping or otherwise fastening the parts in adjusted position.

In operation, A.C. energy may be fed to the primary winding 23 of the transformer 19', through the windings of a saturable core reactor 27', which may be identical to the corresponding component 27 used in the FIG. 1 embodiment. The auxiliary winding 60 of the peaking transformer produces current proportional to the energy supplied to the load through the main windings 55 of the peaking transformer. The shunt winding of transformer 19 produces current proportional to a complex function of the energy flow in the transformer. Current developed in the windings 45' and 60 is delivered to rectifiers 56', 58', through and under the control of variacs 60', 62, for conversion to unidirectional current proportionalv to energy flowing in the transformers l9 and 17. The output sides of the rectifiers 56', 58' are connected together in opposition and in series with the saturating winding 31' of the saturable reactor 27', so that said winding will be excited or energized in accordance with the differential of energy flow in the transformers l7 and 19'.

In the event of a short circuit in the load circuit, or other excessive power drain in the system, the shunt 43' in the main power supply transformers 19 will limit flux density in the transformer core legs carrying the windings 21' and 45', thereby preventing overloading of the power transformer 19'. The shunt 43' and its winding 45' accommodate flux produced by counter electro-motive force delivered from the peaking transfonner circuitry, during the near zero voltage intervals in the wave of energizing power in the transformer 19'. The shunt 43' also accommodates a portion of the flux applied in the transformer core by the excitation of the primary transformer windings 23'. The excitation of the coil 45' thus is an approximate function of the amount of energy flowing in the secondary windings of transformer 19', that is to say, excitation of coil 45' increases, if the energy output of the secondary transformer windings 21' increases, thereby performing a current limiting function, current flow in the coil 45 being low, when the energy drain, in the secondary windings 21', above a selected value, is not excessive; but rises as the energy drain increases above a selected value, which is determined by the air gaps in the bypass 43'.

Current flow in the auxiliary winding of the peaking transformer is low, when power is initially applied to energize the transformer 19', and increases as normal operating conditions are attained. The increase in current flow in the winding 60 is greater than that in the shunt winding 45', as the system approaches normal operating conditions. As the system reaches full load operation, the shunt winding becomes increasingly excited, and so does the auxiliary winding 60, at a greater rate. As winding 60 becomes relatively more excited than the winding 45, the saturating winding 31' receives progressively less excitation which reduces the power supplied to the transformer 19' through the reactor 27. This is the self-regulating effect of the system shown in FIG. 8.

The light produced by the lamp means forming the loads in both of the illustrated embodiments in FIGS. 1 and 2 is of bunched character;.but it would be improper to describe the radiation as continuous. While the lamps discharge at such a rapid rate that the human eye cannot detect the pulses, it can be that the radiation is of stroboscopic character, that is to say, it comprises high intensity light flashes occurring at high frequency. Flash duration is determinedby lamp characteristics and the design of the frequency multiplication circuitry. The wave forms, as seen on the oscilloscope, can be used to determine the duration of the flashes, by measuring the dimensions of the oscilloscope trace to provide a basis for the calculation of the elapsed time involved during the flash producing wave peaks. In this fashion, it has been determined that the flashing interval is of the order of 500 microseconds, or'less, that is to say 0.5 millisecond in lamps energized by means of circuitry of the sort herein disclosed. The foregoing applies to commercially available lamps of the sort presently available; but, the flashing interval depends upon the intensity of the peaks of the energizing wave, which could be much higher, with shorter time duration, if the lamps were capable of accepting higher energy. As and when better lamps become available, flash duration will be shortened. The ringing frequency of the capacitors 87, 89, that is to say, their discharge speed, is a limiting factor in the flashing speed of the lamps. lamp L;

Lamps potentially usable in the herein disclosed light generating systems may comprise high purity quartz or sapphire tubes of variable bore filled with an inert carrier gas or gases, together with a metal or mixture of metal salts, such as indium, mercury, mercury sulphide, mercury amalgams known to produce ultra violet radiation when in the ionized state, mercury bromide, mercury iodide, mercury cadmium and zinc. The inert carrier gases include the noble gases, namely, helium, xenon, krypton, argon or mixtures of these gases. The

1 carrier gases and metallic vapors may be combined in various compositional mixtures and atomic ratios. The lamps should be operated at pressures of less than one atmosphere, at normal operating temperature. High pressure or high temperature operating of the lamps would tend to relatively increase visible and infrared radiation, as compared with the ultra violet component, due to vapor absorption of the ultra violet radiation, under such conditions; and the invention contemplates the provision' of means for cooling the lamps in the event that operating .temperature becomes undesirably high. To this end, silver foil, multiple leaf, vane type mercury condensing radiators 90 may be disposed at each end of the lampL; and, a fan or blower 91 may be provided in position to apply a blast of cooling air upon the lamp. Such fan 91 may be drivingly connected with suitable motive means, such as an electric motor 92 and control means for activating the motor whenever and so long as the lamp temperature exceeds a selected level. To this end, the operation of the motor may be controlled by a thermosensitive element, such as a thermistor 93, disposed in heat exchange relation with respect to the lamp.

These vane type radiators have sufficient radiating surface area to vary the mercury pressure of the lamp from several atmospheres to a small fraction of an atmosphere (200 to 3,500 mm), while energizing the lamp at substantially the same energy level. These radiators may be composed of silver or a comparable material of high thermo conductivity. The function of the radiators is to control the condensation of the metallic vapors by external means, thus allowing variation of the ultra violet output versus the visible and infrared components. The radiators are placed in the vicinity of the electrodes of the lamp, although there is no limitation as to placement. Locating the radiators near the electrodes is preferable, in order to achieve a satisfactory balanced radiation output, and also to increase lamp life by increasing ionic bombardment at the lamp electrodes, thus substantially reducing electrode sputtering. This is useful because it contributes to cleanliness and reliability of the lamps, while producing more ultra violet radiation for the same power input. The use of radiators, however, causes no change in visible radiation emitted by the lamps, but, by decreasing temperature, the radiant output in the near and far ultra violet range is substantially increased as, for example, from l8 to foot candles.

Where used in promoting photo chemical reactions, the lamp L, in the FIG. 1 embodiment, may comprise a mercury-xenon Hanovia lamp (No. 47Al6). This is a 3,500 watt lamp having a 48 inch arc, and it is operated as a medium pressure lamp (760MM) with a peak output of the order of 3,l003,600 angstroms. An elipsoidal-parabolic or other suitably shaped reflector may be used with the lamp in order to provide maximum reflection and application of radiation upon the irradiation subject. The lamp may be operated at potentials ranging between 600 and 1,000 volts-with current flow of the order of 5.8 to 3.8 amperes (RSM values), or approximately 3.5 to 3.8 kilowatts.

The lamps shown in the FlG. 2 embodiment may comprise four 550 watts, mercury-xenon, Hanovia 'larnps (No. 673Al0), providing 4.5 inch arc lengths.

These lamps operate at pressures of less than one atmosphere, and their output is predominantly that of the mercury vapor arc because of the relatively small quantity of xenon incorporated therein. The lamps normally have a peak output of the order of 2,800-2,900 angstroms. Any preferred reflector shape may be employed to apply the light emitted by the lamps for purposes of promoting photo chemical action. The lamps may be energized at potentials ranging from 300 to 500 volts, with current flow within the range from 7.5 to 4.4 amperes (RMS values), or approximately 2.2 kilowatts.

By energizing the lamps with high voltage sharply peaked energy waves, as taught by the present invention, the lamps yield more ofa continuum than the line output thereof when operated with conventional sinusoidal A.C. energy. In addition, the spectrum of the radiation is shifted toward the ultra violet region and the intensity of the ultra violet spectrum is substantially increased in relation to the visible and infrared spectrum components.

In addition to the condensers 87 and 89 connected with the autowinding 59 of the peaking transformer 17, a power factor correcting capacitor 95 may be connected in parallel with the primary winding 23 of the transformer 19, said capacitor having a suitable rating for the desired power factor correction. If desired, an auxiliary power factor correcting capacitor of suitable rating may additionally be connected across a portion of the primary winding 23, as shown in FIG. 1.

Suitable instrumentation for revealing current and potential conditions in the several portions of the apparatus may, of course, be provided. As shown, -25 v. voltmeters 99 may be provided for indicating the DC. voltages applied to the saturating windings 31 and 131 of the reactors 27 and 27', in the FIG. '1 embodiment. An 0-300 V. AC. voltmeter 100 may be connected to show the RMS value of'potential applied to the primary winding 23 of-the transformer 19 in the FIG. 2 embodiment. An 0-l,500 v. A.C. voltmeter 101 may be provided to show the RMS value of the voltage of the energizing wave applied to the lampmeans, in both the FIG. 1 and FIG. 2 embodiments, while a suitable l-lO amp. (RMS), A.C. ammeter 103 may be connected in series with the load, in each embodiment, to disclose the amount of current delivered. To reveal the peak voltage applied to the load, in each embodiment, a kva, selenium rectifier 105, in series with an 0-6,000 V. DC. voltmeter 107, maybe provided, an 0.05 mfd., 6,000 v. capacitor 109 being connected in parallel with voltmeter 107.

In order to maintain radiation, produced by the lamp means, at a uniform intensity level, a photo sensitive cell 111 may be positioned in the emitted radiation and connected to control suitable relay means 113 for adjusting the voltage regulating element 135, to thereby vary the energy delivered to the input windings of the peaking transformer 17 by the secondary or output winding 21 of the ballast transformer 19. A photo sensitive cell and relay,likc the cell and relay 111 and 113, may also be. employed to adjust the voltage regulating element 35. Either or both of the regulating elements 35 and 135 may thus be adjustably controlled to maintain the lamp means in operation at uniform radiation output intensity.

Still another arrangement'for maintaining uniform radiation intensity is shown in FIG. 9, wherein the output circuit of the opposed rectifiers 56' and 58' connected in series with the saturating winding 31 contains an adjustable resistor 115 connected in series with the circuit, with a relay switch 117 connected in parallel with the resistor, so as to short circuit it, when the switch is closed, and to make it effective, as a series component in the circuit, when the switch is open. A photo sensitive cell 111, disposed in position to be influenced by the radiation emitted by the devices 13', is connected to actuate the operating coil 119 of the relay switch through a conventional translation system 113'.

As and when the radiation intensity of the units 13' diminishes, due to reduced line voltage, or aging of the units, or other cause, the relay switch will be operated to reduce the resistance in circuit and thus increase the current (DC) delivered through the rectifiers to the winding 31 of the transductor 27. This, in turn, will increase the voltage applied from thepower source upon the primary winding 23 of the transformer 19, thereby increasing the power applied on the radiating units 13' and intensifying the output radiation. Where the lamps 13' emitultra violet radiation, the sensitive cell 111' may conveniently comprise a high vacuum cadmium cell having peak response to radiant wave lengths of the order of 2,537 A.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the form herein disclosed being a preferred embodiment for the purpose of illustrating the invention.

I claim:

1. Apparatus for producing high intensity radiation, comprising a gaseous discharge lamp filled with an inert carrier gas or gases, together with a vaporizable metal or metal salt, forming a load, and circuitry activated from a source of alternating current power to produce a series of discrete pulses having a wave form characterized by sharp high peaks of short duration, said circuitry embodying a driving transformer providing a constant voltage and current flow in its output secondary winding and a peaking transformer having an input winding and an output winding with an air gap in the core sized to control the duration of peaking to less than one-half cycle and means to control the pulse amplitude comprising a capacitor connected in parallel with said input winding of said peaking transformer, means connecting the output of said driving transformer in series with the input winding of said peaking transformer, and means for connecting opposite sides of the load with opposite, ends of said peaking transformer output winding.

2. Apparatus as claimed in claim 1 in which said air gap does not exceed 0.007 inch.

3. An'apparatus as claimed in claim 1 which comprises adjustable means connected with said core of said peaking transformer for adjusting the width of said air gap.

4. Apparatus for producing high intensity radiation comprising a gaseous discharge lamp filled with an inert carrier gas or gases, together with a vaporizable metal salt, forming a load, and circuitry embodying a peaking transformer having an input and an output including an autowinding, said output being connected to opposite sides of said load to energize said load, said peaking transformer having a core of magnetic material linked with said autowinding and formed with an air gap sized to produce alternating current output pulses having a wave form characterized by sharp high peaks of short duration less than one-half cycle, adjustable means connected with said core for adjusting the width of said gap to alter the configuration of the output pulses, a capacitor connected in parallel with said autowinding which functions to limit the amplitude of the output pulses, means connected to the input winding of said peaking transformer for supplying alternating current comprising a step up, high reactance transformer, a source of alternating current connected to said step up transformer, and control means comprising a saturable reactor having a winding saturable with direct current connected to said step up transformer to control the flow of alternating current from said step up transformer to the input winding of said peaking transformer.

l 5. Apparatus as set forth in claim 4, wherein the step up transformer has a core provided with magnetic shunt means disposedbetween the primary and secondary transformer windings for by-passing from the secondary winding a portion of the magnetic flux induced in the core by the primary winding, when energized.

6. Apparatus as set forth in claim 4 wherein the control means comprises automatic regulating means to adjust the voltage at which energy is applied on the winding saturable with direct current.

7. Apparatus as set forth in claim 5 including regulating coils inductivelypoupled with said magnetic shunt means, and regulating means for controlling current transformer for producing current fluctuating as a function of flux intensity in the core of said peaking transformer, and means for energizing the saturating winding as a function of the measured flux intensities in the shunt and the core of the peaking transformer. a: a:

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,75 ,324 Dat figgtember 11 1913 Inventor(s) CARL J WARNEKE It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 14, "infernals" should read --intervals.

Column 4, line 15 "arrange" should read -range-; same line, after "between" insert --a low of the order of a few hundred watts to a high level of-.

Column 6, line 20, "the" should read -this-; line 34, "tnat" should read --that--; line 50, "as" should read --at.

Column ll, line 39, cancel "lamp L; after "lamps."

Column 12, line 21, "increasing" should read -decreasing.

Signed and sealed this 15th day of April 1975.

u 5.3. Attest:

C. l-LKRSHALL DAIFN T-Z'JI'EI C, IIASOET Commissioner of Patents attesting Officer and Trademarks ORM PO-1 USCOMM-DC 60376-P68 U.S. GOVERNMENT PRINTING OFFICE 1,55 O3G5-334,

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US6410872 *Dec 14, 1999Jun 25, 2002Key Technology, Inc.Agricultural article inspection apparatus and method employing spectral manipulation to enhance detection contrast ratio
US7897895 *May 1, 2006Mar 1, 2011General Electric CompanySystem and method for controlling the power level of a laser apparatus in a laser shock peening process
US8686576 *Dec 28, 2011Apr 1, 2014The United States Of America As Represented By The Secretary Of The ArmySystem and method for harvesting electrical energy by linear induction
US20090120914 *May 1, 2006May 14, 2009Wayne LawrenceSystem and method for controlling the power level of a laser apparatus in a laser shock peening process
WO1998023134A1 *Nov 19, 1997May 28, 1998Micro Tech LimitedLamp driver circuit and method
Classifications
U.S. Classification315/246, 315/278, 315/282, 315/276
International ClassificationH05B41/34, H05B41/30
Cooperative ClassificationH05B41/34
European ClassificationH05B41/34