US2193071A - X-ray apparatus for control - Google Patents

Description

March 12, 1940. w. M. LEE

7 X-RAY APPARATUS AND common Filed Aug. 18. 1938 INVENTOR. LE

Patented Mar. 12, 1940 William M. Lee, Covington,

liclleysKoett Manufacturing Company,

Ky assignor to The ccrporated, Covington, K a corporation '01:

Ohio

Application August 18, 1938, Serial No. 225,592

Thisinvention relates to an: X-ray apparatus and control. By the use of the circuit shown, or its equivalent, the followingfunctions are performed and none can be altered without altering all of the rest:

1. The proper temperature for the X-ray tube filament is selected.

2. The proper area of focal spot for a given current is established for the X-ray tube target.

3. A proper temperature for the filament of the rectifying tube or tubes is selected.

4. The volt meter is compensated so that the true voltage across the X-ray tube can be predetermined and the voltage indicated thereby for its any of the settings.

5. Ballast resistance is inserted into'the primary of the high tension transformer when the apparatus is to be used for fiuoroscopy and therapy. It is taken out when the apparatus is to no be.used for radiography.

The; advantages residing in this type of control are that by the turning of a single knob to select a proper milliamperage, all of the other adjustments listed are made coincidentally and auto.-

cs matically. The bad effects upon tube life due to,

underheating or overheating filaments for the current employed are entirely eliminated; For

this reason, X-ray and valve, tubes last considerably longer when this type of control is em- :m ployed. Due to the automatic selection of the area of the focal spot for the current, one is much less likely to damage the tungsten target by overheating the focal spot. r In, the drawing, til-40 are the leads ofthe -.;:5 main service line and H-H thepoles of a combination main switch and overload circuit breaker. I2 is the coil of the latter. paratus is commercial and not novel. lead from this switch and breaker to one a an autotransformer winding l5.

I3 is a end of sation switch so that the voltage on the entire apparatus maybe kept constant regardless of fluctuations of line voltage, by varying the position of arm l6.

The autotransformer i5 50 is also provided with two dial switches, I! and IS, the former being for major, and the latter for minor voltage adjustment/Their function is to select the proper voltage to be applied across the Xray tube exci- 55 tation circuit.

Such ap- I4 is a second lead going from. the circuit breaker to a row of.

Claims. .(Cl. 250-44) Switch I! is connected to a magnetic contactor or magnet switch 2| .by alead l9 through a ballast resistance 20. 1 The other side of the autotransformer is connected to the same contactor through a lead 22. From the output terminals of the contactor, leads 23 and 24 connect directly to the high tension transformer 25. This contactor 2! is of any suitable well-known type, and as shown may consistof three stationary" contacts 2m connected with the two output terminals. Movable contacts 21b are carried by a frame structure secured to a plunger 2 I0 which is 0per able by a solenoid Zld which is connected in turn with terminals for an energizing and operating circuit. This circuit is energized from any suitable controlled source to close contacts 2th upon contacts 21a to apply power to the high tension transformer 25 only when high voltage to the X-ray tube. The voltage to be applied, however, is indicated by the kilovoltmeter '12 as will hereinafter beset forth.

From a proper voltage tap on the autotransthe X-ray tube filaments and 36.

The X-ray tube 34 is provided with two filaments 35 and 36 which are supplied with heating it is desired to apply a former [5, a lead 26 connects to a voltage stabil- 1 izer 21., the function of which is toenergize or supply the proper energy to the filaments of l both the X-ray tube and the valve tubes. Lead current by two'filament transformers 32 and 33.

30 is a compensating transformer which is reversely connected to buck the voltage supplied to the primaries of transformers 32 and 33 when the voltage to the primary of the high tension transformer is increased. One lead of each of the secondaries 31 and 38 of the filament transformersare connected together; the common lead 39 so made is connected to the junction of the two filaments. The other ends 40 and 4| of the secondaries are connected respectively to the remaining leads of the X-ray tube filaments.

V In order to understand how the compensating transformer 30 is arranged to buck the voltage in the primaries of transformers 32 and 33, it is necessary'to describe the switching means which performs most of the integration of this control. 42 is a four deck, multi-position switch and comprises all of the contacts shown within the panel 43. The decks are numbered l, 2, 3 and 4 from top to bottom. No. 2 controls the heating and focal spot selection of the X-ray tube filaments. It is to be noted that the left hand bank of contacts is divided into two connected groups 44 and 45. Each one of these groups is connected to the primary of each of the two filament transformers through leads 46 and 41. The two groups are optionally connectable to the tapped As the voltage applied to thisinput side is increased it follows that the voltage applied to transformer 30 is also increased, including the output voltage of its secondary. The latter is connected in series with the primaries of filament transformers 32 and 33. The connection is so polarized that the voltage of the secondary and the voltage supplied to the primaries of transformers 32 and 33 are in opposition to each other. If there were no reduction in the heat sup- "plied to the X-ray tube filament as the voltage is increased across the tube, then the amount of current through the tube wouldrise to an "undesirable value. By regulating the compensating transformer 30 to just theproper value, this current rise can be exactly neutralized and that relation is here employed.

Focal spot selection is made by reason of the separation of sections 44 and 45, which connects 1 either the primary of the filament transformer 32 or 33 to the circuit as desired, thus changing the filament which is energized.

.The calibration of the voltmeter I2 is maintained by deck I and the auxiliary winding 53 which is wound on the core of the autotransformer I5. This arrangement has been fully described in my co-pending application Serial No. 201,592 filed April 12, 1938. This auxiliary winding 53 as previously described, has, connected across it, a tapped resistance 54. The various taps from this resistance are connected to contacts on deck I of switch 42. The contacts on the left side of deck I' are all connected together and in turn, to one side of the voltmeter 12. The other side of the meter is connected to lead 19 which is one primary lead of the high tension transformer. The other side 22 of the primary is connected to one side of resistance 54 and auxiliary winding 53 by means of lead 55.

The auxiliary winding 53 with the resistance .54 connected across it is connected into the voltmeter circuit in such a manner so that the volt age generated in coil 53 opposes the voltage supplied tothe voltmeter by leads l9 and 22. The amount of bucking produced by this opposition of voltage is determined by which tap of resistance 54 is in circuit. This arrangement enables the reading of the voltmeter to be compensated so that the reading of the instrument corresponds .to'the true voltage applied to the X-ray tube for any desired load.

The purpose of deck 3 is to adjust the valve tube filaments automatically. The left group of contacts 55 in this deck are connected together and the entire group is connectedby a short lead 51 into lead 29 and so to the switch 21. In the right hand group of contacts each button is connected to a tap in a filament transformer resistance 53. A contact arm 4% is rotatable to bridge the right and left hand contacts. Resistance 58 is connected in series to a lead 59 and to a bank of independent resistors 60, GI and 62, the function of which is to bring each valve tube filament to the same heat as the others. The resistors are each in series with the primary of their own filament transformer, l3, l4 and 15 respectively, said filament transformers being provided for the purpose of furnishing low voltage heating current to the filaments of the valve tubes. As shown these filament transformers have their secondary windings connected with four rectifier tubes in a conventional bridge circuit 16. The rectified high D. C. potential from this bridge connected rectifier is supplied directly to the X-ray tube 34, one conductor 71 therefrom being connected to the common X-ray tube filament or cathode lead 39 and the other conductor 18 being connected to the X-ray tube target or anode I9. The other end of the primaries are connected by leads 65 and 52 back to the switch 21. It is evident therefore, that all of the valve tube filaments can be raised or lowered as to their temperatures by the deck 3 working through resistor 58 to correspond to any X-ray tube load selected on deck 2, while the filament loads are equalized by means of resistors 50, SI and 62.

The purpose of deck 4 is to cut resistance in or out of the circuit, depending upon whether radiography, fiuoroscopy or therapy is being performed. When the two latter are desired, the resistance is cut in.

The contacts on deck 4 comprise two groups 66 ancLB'I, unconnected except by the contact arm 490. Between the groups there are two dead contacts 68 and 69. So long as the contact arm bridges 65 and 61, resistance is cut out. When 68 and 59 are bridged, resistance 20 is cut in. Cutting out takes place by shorting through leads l0 and H to the magnetic contactor or magnet switch 2 l In this apparatus, the four decks are of course controlled by a single shaft designated 80 and the presence of which is implied in the statement that 42 is a four deck switch.

Operation occurs as follows: Main switch H is closed, thereby energizing the autotransformer l5. The proper X-ray tube load is selected by rotating the shaft of the four deck switch 42 by means of a suitable knob (not shown) until the load selected is indicated by the legend stamped upon the contact on deck 2. Then simultaneously deck l adjusts the calibration of the voltmeter i2 so that all that is necessary to obtain the desired kilovoltage is to adjust the auto major and minor dial switches I! and [8 until the meter indicates the potential desired. Decks 3 and .4 are at the same time respectively adlusting the valve tube filaments to proper temperature and cutting in or out the ballast resistance 20. It is impossible to select a load for therapy that will be injurious to the tube because the lowest loads in the scale are those selected for fiuoroscopy and therapy. This is merely to say that the dead contacts 68 and 69 are the first ones bridged on deck 4.

I'claim as my invention:

1. An X-ray apparatus and control including four dial switches, operating means for movably adjusting said switches simultaneously as a unit, said switches connecting respectively the elementsof a prereadingkilovolt-meter circuit for reading the high tension voltageto be applied to theX-ray tube, an=X-ray tube filament temperature: selecting and heat applying circuit, a, "valve tube filament supplying and regulating circult, and a ballast resistance applying and disconnecting circuit for applying the resistance e during the practice of therapy and fluoroscopy, all

of said circuits being correlated with each other and controlled by said switches whereby each change in adjustment of the switch operation means efiects corresponding adjustments of each of the circuits. i

2. An X-ray apparatus and control including, an X-ray tube filament heating and temperature selecting circuit, a rectifying tube filament heat- I ing and regulating circuit, a voltmeter compensating circuit including a voltmeter for indicating the high-tension, voltages to be applied to the X-ray tube, a ballast resistance and a circuit in which said resistance is to be inserted when the X-raytube isto be used for therapyor fiuoroscopy, each of said circuits having a plurality of current adjusting means correlated to adjustments of the :other circuitas aid means, for regulating the circuits for the various adjustments including a multi-deck rotatable switch, and operating means for movably adjusting all decks of said switch simultaneously as a unit whereby all of said circuits can be regulated simultaneously to their correlated electrical values. p

3. An X-rayapparatus and control including,

a multi-deck switch, each deck switch having multiple contacts and a movable contactor co-' operating therewith, meansfor movably adjust ing all decks thereof simultaneously as a unit, a

rare-reading voltmeter circuit connected to one deck of said switch, the elements of said circuit comprising a voltmeter, a resistance, an autotransformer having its output leads providing the i circuit connections and the power supply for this X-ray tube, an auxiliary coil for said auto-transformer arranged to oppose the voltage generated by said auto-transformer, said resistance being connected directly across said auxiliary coil, one side of said 0011 being connected toone output lead of said auto-transformer, said resistance being tapped in a plurality of places, each tap thereof being connected to a separate contact of said deck of said multi-deck switch, the movable contactor of said switch which is engageable with said contacts thereof being connected to said voltmeter, and said voltmeter being connected to the other output lead of said auto-transformer, and the remainingdecks of said switch aifording connections for respectively, an X-ray tube filament heating current selecting and applying circuit, a valve tube filament supplying and regulating circuit to govern the rectification of the high tension current suppliedto the X-ray tube, and a ballast resistance applying and disconnecting circuit to insert ballast resistance in the X-ray tube power supply circuit when said X-ray tube is to be used for therapy-or fluoroscopy, each of said circuits having a plurality of current adjusting means correlated to the adjustinents of the other circuits, whereby all said circuits can be regulated simultaneously to their correlated electrical values by the adjustment of said multi-deck switch.

4. An X-ray apparatus and control including,

a multi-deck switch, each deck switch having multiple contacts anda movable contactor c0- operating therewith, means formovably adjusting all decks thereof simultaneouslyas a unit, an

,the other side of said deck of said multi-dec'k switch being divided into two groups of taps, each group being separately connected to one primary leadv of one of the two filament transformers, the remaining two leads of said transformers being connected together and also connected to one secondary lead of said filament compensating transformer, the other lead of the filament compensating transformer being connected to another tap of the auto-transformer,

the two primary leads of said compensating transformer being connected to taps of theautotransformer, the remaining decks of said switch being connected respectively to a pro-reading voltmeter circuit for reading the high-tension voltage to be'ap'plied to the X-ray tube, a-valve tubefilament supplying and regulating circuit for rectifying said ballast resistance circuit for applying high-tension current "and a applying .1 and disconnecting resistance to the circuit when the X-ray tube is to be used for therapy or fluoroscopy, and means in the circuits connected to said latter decks of the multi-deck switch for adjusting the various circuits in correlation with each other whereby all of said circuits can be regulated simultaneously to theircorrelated electrical values by the adjustment of said multi-deck switch.

5. An X-ray apparatus and control, including a multi-deck switch, each deck switch having multiple contactsand' a movable contactor cooperating therewith, meansfor movably adjust- .ing all decks thereof simultaneously as a unit, a valve tube filament supplying and regulating cir cuit connected to one deck of said switch, the elements of said circuit comprising a tapped resistance, a plurality of tapped resistors, a plurality of filament transformers and an autotransformer, the deck of said multi-deck switch being divided into two connected groups of an an amrneter, afilament compenequal number of taps, one of said groups being directly connected to each other and the taps of the other group being each connected to the taps of said resistance, and one end of the resistance being connected to one end of each of said reconnected to one of the primary leads of said filament transformers, theother primary leads thereof being connected together andalsoto said auto-transformer, and the remaining decks of sistors, the other ends of the resistors being each l said switch being connected respectively to a prereading voltmeter circuit for reading the voltage of the high-tension current to be applied to the X-ray tube, an X-ray tube filament heating current selecting and applying circuit and a ballast resistance applying and disconnecting circuit in which the resistance is applied when the X-ray tube is used for therapy or fluoroscopy, all of said circuits being inserted between the terminal leads of said auto-transformer, and means in the circuits connected to said latter decks of the multideck 'switchfor adjusting the variousicircuitsin correlation with each other whereby ,all of said circuits can be regulated simultaneously to their 'ie the other terminal of the ammeter becorrelated electrical values by the adjustment of 7 said multi-deck switch.

6. An X-ray apparatus and control including .a multi-deck switch, each deck switch having multiple contacts and a movable contactor cooperating therewith, means for movably adjusting all decks thereof simultaneously as a unit, a ballast resistance applying and disconnecting circuit connected to one deck of said switch, the elements of said circuit comprising a ballast resistance, two connected groups of taps in said deck of said multi-deck switch, a pair of dead contacts, one of said dead contacts lying between each group of contacts, eachend of said resistance being connected to an end of said groups of switch deck contacts, and the remaining decks of said switch being connected respectively to a prereading voltmeter circuit to test the voltage of'high-tension current to be applied to the X- ray tube, and a X-ray tube filament temperature selecting and heating currentapplying circuit-and avvalve tube filament supplying the regulating circuit, all of said circuits being inserted between the terminal leads of an autotransformer, and means in the circuits connected to said latter decks of the multi-deck switch for adjusting the various circuits in correlation with each other whereby all of said circuits can be regulated simultaneously to their correlated electrical values by the adjustment of said multideck switch.

'7. An X-ray apparatus and control including, a multi-deck dial switch having its decks ar ranged one above another with pole connections on opposite sides thereof, an autotransformer having a connection with a pole on one side of said switch, the other side of said switch having connections with a separate deck, a kilovoltmeter connected with one deck and adapted to 'for different corresponding positions of the switches of the different decks, whereby when the deck switches are adjusted from one corresponding position to another the current conditions in the. several circuits will be correlated in all switch positions for operating the X-ray tube.

8. The, combination set forth in claim 7 and, in addition, afourth deck, and a ballast resistor connected through said deck, whereby ballast resistance may be cut in the power circuit for reducing high voltage to the X-ray tube during therapy treatment.

9. An X-ray apparatus and control comprising an X-raytube having a plurality of heatable filaments, a power supply and an exciting circuit for applying a potential across the X-ray tube, control means in said circuit for varying the tube excitation inincrements, circuit means for applying a potential to each of the plurality of filaments, a reversely connected transformer j havinga winding connected with said tube ex,-

citation circuit and another winding connected with said filament circuit for regulating the potential of the filament circuit in accordance with the potential of the X-ray tube exciting circuit and a single operating means for selecting the filament to be heated and for "adjusting the potential across the selected filament,

10. An X-ray apparatus and control comprising an Xray tube having a plurality of heatable filaments, a power supply and an exciting circuit for applying a potential across the X-ray tube, control means in said circuit for varying the tube excitation in increments, a ballast resistance in said tube exciting circuit for controlling the potential applied to the X-ray tube, switching means for removing the ballast resistance from the circuit, circuit means for applying a potential to each of the plurality of filaments, a reversely connected transformer having a winding connected with said tube excitation circuit and a second winding connected with said filament circuit for regulating the potential of the filament circuit in accordance with the potential of the X-ray exciting circuit and a single operating means for simultaneously actuating said ballast,

resistance switching means, selecting a filament to be heated and adjusting the potential across the selected filament. WILLIAM M. LEE.

CERTIFICATE OF CORRECTION.

Patent No. 2,195,071. 1 March 12., 19110.

WILLIAM H. LEE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page h, first column, line 22, claim 6, for "the" read and; and that the said Letters Patent should be read with this correction therein that the same may con form to the record of the case in the Patent Office Signed and sealed this 9th day of April, A. D. l9h0.

Henry Van Arsdale Acting Commissioner of Patents

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