US3027460A - X-ray device - Google Patents

X-ray device Download PDF

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Publication number
US3027460A
US3027460A US796925A US79692559A US3027460A US 3027460 A US3027460 A US 3027460A US 796925 A US796925 A US 796925A US 79692559 A US79692559 A US 79692559A US 3027460 A US3027460 A US 3027460A
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United States
Prior art keywords
voltage
ray tube
rotation
switch
contact
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Expired - Lifetime
Application number
US796925A
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English (en)
Inventor
Boldingh Willem Hondius
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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Priority to US163002A priority Critical patent/US3164723A/en
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Publication of US3027460A publication Critical patent/US3027460A/en
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/26—Measuring, controlling or protecting
    • H05G1/30—Controlling
    • H05G1/32—Supply voltage of the X-ray apparatus or tube

Definitions

  • the present invention relates to voltage regulating circuit arrangements for X-ray tubes.
  • X-ray tube circuit arrangements usually comprise means for regulating the voltage between the anode and the cathode of the X-ray tube, i.e. the tube voltage.
  • the tube voltage i.e. the tube voltage.
  • some X-ray devices are known in which the effective tube voltage always retains the same mean value, but these are usually small-size devices for certain uses,
  • Means for regulating the voltage is necessary in taking X-ray photographs, if the required tube voltage differs for each kind of object to be photographed. For example, the tube voltage required for fat patients is higher than that for thin patients. Furthermore, in choosing the voltage, allowance is made for the different X-ray absorption characteristics ofthe various parts of the body.
  • An X-ray device is usually provided with tables or graphs from which the adjustment of the load values may be derived for most examinations occurring in practice in which an X-ray photograph is to be taken.
  • Such a graph or table does not supply all the details which may affect the absorption of rays of an object. Composing all the data for each individual object would become too expensive besides leading to an expedient which is not particularly surveyable and hence diflicult to handle. In view thereof, the indications supplied by the graphs or tables are limited to the cases of most frequent occurrence. It is possible to distinguish a plurality of groups of objects for which the energy required for obtaining a given blackening of the photographic plate and the optimum tube voltage at which the photographs are taken differ considerably. Examples of objects arranged in different groups or categories are the skull, the limbs, the thorax and the trunk.
  • the present invention relates to an X-ray circuit arrangement comprising means for regulating the voltage between the anode and the cathode of the X-ray tube, in which the tube voltage automatically increases during the exposure time for taking a photograph.
  • a single control range in which the voltage can traverse all values which may be used for taking photographs affords the advantage that the choosing of the voltage value may be omited.
  • a disadvantage is that the quantity of rays supplied to the patient is increased to an unnecessary extent. According to the invention, this disadvantage is substantially avoided by the use of means for regulating the tube voltage, which allows, inter alia, the tube voltage upon switching on the X-ray tube to be adjusted, as well as the value of the voltage variation, i.e., the range through which the tube voltage varies, and the rate at which the voltage varies.
  • FIG. 1 is a schematic diagram of an embodiment of the circuit arrangement of this invention comprising electro-mechanical voltage regulating means;
  • FIG. 2 is a schematic diagram of still another embodiment of the circuit arrangement of this invention.
  • FIG. 3 is a partial sectional view of part of a component which may be utilized in the embodiment of FIG. 2.
  • the X-ray tube 1 is connected to a high-voltage transformer 2; anode 3 being connected to one terminal of secondary winding 4 of transformer 2 and cathode 5 being connected to the other terminal thereof.
  • the cathode 5 is also connected to a secondary winding 6 of a transformer 7 which supplies the heating current for the cathode 5.
  • the voltage for the primary winding 8 of high-voltage transformer 2 is supplied by a regulating transformer 9.
  • the transformer 9 is connected to voltage mains terminals 10 and 11 via a main switch 12.
  • FIG. 1 contains only the necessary elements to illustrate the principle of this invention and which also include a time-switching device.
  • This may be an electronically operating time switch which may be mechanically adjusted to a given exposure time. It is alternatively possible to employ a device having automatic limitation of time.
  • a device of the last-mentioned kind is shown in FIG. 1. It comprises a photo-electric 8 cell 13, which is sensitive to X-rays or which comprises a fluorescent screen for converting X-rays into visible light.
  • a current source 14 and a resistor 15 are connected in series with the photo-electric cell 13. The current traversing the resistor 15 is determined by the internal resistance of the photo-electric cell, which is high at a low intensity of the incident radiation and decreases upon increasing intensity of the rays.
  • the voltage across the resistor 15 varies in the reverse sense and serves to charge a capacitor 16.
  • the charging voltage of capacitor. is proportional to the quantity of rays and serves as a measure of the blackening of the photographic plate, which, in taking photographs by means of an X-ray tube, is positioned, together with the object, between the photo-electric cell and'the X-ray tube.
  • the voltage on the capacitor 16 is applied to a control grid 17 of an electron discharge tube -18 and acts upon the intensity of the electron current produced between an anode 19 and a cathode 20.
  • the anode circuit includes a coil 21 of an electro-rnagnetic relay and a voltage source 22.
  • the anode circuit includes a switch, illustrated, by way of example, as a pressbutton switch 23.
  • the capacitor 16 Before the photographing process starts, the capacitor 16 is without voltage.
  • the grid 17 has cathode potential so that, after pressing the press-button switch 23, an anode current flows, which energizes coil 21'of the electromagnetic relay, so that a switch 24 is closed.
  • themain switch 12 Before operating the press-button switch 23, themain switch 12 is closed and voltage is applied to a primary winding 25 of heating-current transformer 7.
  • the thermionic cathode 5 ofthe X-ray tube 1 is thus heated. Due to the closure of switch 24, the high-voltage transformer 2 receives voltage and the X-ray tube 1 is made operative.
  • the voltage source 14 charges capacitor 1:6, so'that the potential on grid 17 of the discharge tube 18 varies in a negative-sense with respect to the cathode '20 and, after a certain period, the anode current decreases to so low a value that the relay coil 21 releases the switch 24.
  • the opening of switch 24 causes the supply of current to the X-ray tube to be interrupted and the photographing process to be terminated.
  • variable resistor 26 comprises an annular body on 'which resistance wire is wound. Its sliding contact 27 is moved by means of a continuously rotating shaft 28 which is driven by an electric motor 29 switched onby the closure of main switch 12. Rotary shaft 30 of sliding contact 27 and the shaft 28-of the electric motor are connected by meansof a friction coupling 31.
  • variable resistor 26 there are arranged two abutments 32 and 33 which can check the sliding contact 27 but which may also be removed from the path of the sliding contact.
  • the abutment 32 at the beginning of the path of the resistor is a pin which may be removed from the vicinity of resistor 26 by energization of' a magnet winding 34.
  • the winding 34 is energized when the magnetic switch Holmes and hence when the X-ray' tube is switched on. Due to the withdrawal of the pin," the- 'sliding contact 27 is rotated by the continuously-rotating shaft 28 via the coupling 31 and displaces itself along the resistor 26 to the other extremity.
  • the resistance in the primary circuit of the high-voltage transformer -2 is thus successively reduced and finally completely short-'circuited.
  • the second abutment 33' is situated at the area where the resistor 26 terminates. It is operated dififerently from the first-mentioned abutment 32.
  • a coil 35 is ener- 'gized, the movement of sliding contact 27 is blocked by the'iabutment '33 and when the energization disappears,
  • the tube voltage is low.
  • the X-ray tube voltageincreases moves past the second abutment '33, which has been with drawn due to the de-energization of coil 35, and comes to rest against the first abutment 32, so that the initial'condition is restored and a new photograph can be taken.
  • the quantity of rays required for producing the desired blackening of the photographic plate requires a shorter exposure period than for a photograph which is taken of a thicker object or one which has a greater X-ray absorbing characteristic.
  • the radiation obtained at the lower voltage is valueless for obtaining a given blackening. This radiation thus unnecessarily increases the skin dose and it is therefore desirable to avoid it.
  • the circuit arrangement of theinvention has the feature that thevoltage between the anode 3 and the cathode 5 of the X-ray tube 1, at which the photographing process begins, is adjustable.
  • the abutment 32 which checks the slide ing contact 27 in the initial'position, is displaceable along the periphery of the variable resistor .26 in the direction of the sliding contact 27 as indicated by arrow 36.
  • the sliding contact 27, after the driving motor 29 has been switched on and hence as soon as the main switch '12 is closed moves towards the position of the abutment 32,. whereby the portion of the resistor located between the connection of the current supply wire and the abutment 32 is short-cir'cuited. The portion of the resistor which remains switched on is then smallerso that operation of the circuit arrangement is started with a higher initial voltage.
  • the boundary of the displacement of the sliding contact 27 is adjust-able in order to limit the increase in tube voltage to a value lower th-anthe peak value.
  • the abutment 3-3, at the end of resistor 26, is displaceable along the periphery of resistor 26 in the opposite sense to the direction of rotation of sliding contact 27 as indicated by arrow 37.
  • the abutment 33 then stops the sliding contact 27 before the latter has performedthe complete rotation, a portion of the resistor 26 remaining switched into thecircuit.
  • the current strength with which the X-ray tube is loaded has not been considered. Since the current strength also determines the time of exposure,
  • the rotary potentiometer is also designed as a switching element for terminating the exposure time.
  • the resistor 26 isconnected in series with the primary winding 8 of high-voltage transformer 2, the secondary winding 4 f which is connected'to the anode 3 and the cathode 5 of the X-ray tube 1.
  • the autotransformer 9 is energized.
  • the current supply ⁇ to the primary winding 8 of high voltage transformer 2 remains inter-- rupted as long as the electromagnetic switch 59 is open.
  • Switch 59 is operated by an energizing winding 64..
  • the supplycurrent for the relay winding 64 passes via two contact devices 63 and 65, which are connected in series and which serve to'switch bu and. switch otiithe. energizing current, respectively.
  • the rotary contact 27, which is also designed as a switching arm, is seated on the shaft of the resistor 26.
  • the rotary contact 27 keeps the contacts 61 and 62 of the contact device 63 open, so that the circuit of the relay winding 64 is interrupted.
  • the X-ray tube 1 is made operative by switching on the electric motor 66, which drives a shaft 60 of the rotary contact 27.
  • the motor 66 starts running when a push button switch 67 is closed.
  • the contact 27, which is also a switching arm is rotated by the rotary shaft 60, resulting in the contacts 61 and 62 of the contact device 63 being closed and the relay winding 64 being energized. The latter closes the switch 59 and hence connects the supply current to the Xray tube 1.
  • a regulation of the speed of rotation of the electric motor 66 serves to match the exposure time to the various groups of objects, the contact 27 moving from the beginning to the end of the resistor 26 within 0.3, 1.5 and seconds.
  • the shaft 60 of the current collector is therefore driven by the electric motor 66 via a speed regulator 70.
  • Another possibility of controlling the exposure time consists in positioning the terminal contact device 65 to be displaceable along the periphery of the resistor 26. This may be combined with the use of speed stages, so that during each of these stages exposure times may be chosen shorter than those required for traversing the whole resistor. This also results in a decrease of the voltage rise at the X-ray tube 1. In order to obtain the same blackening of the photographic plate when utilizing a shorter exposure time and a voltage which rises to a lesser value so that the mean X-ray tube voltage is lower, it is necessary to increase the X-ray tube current. Automatic regulation of the X-ray tube current may be obtained by coupling the movable contact device 65 to a device 71 which adjusts the heating current of the X-ray tube.
  • rotary contact is not also operative as a switching arm, but a separate arm 72 operates the contact devices 63 and 65, it is possible to regulate the increase in tube voltage and exposure time individually.
  • the switching arm 72 is arranged as a separate rotary arm on the shaft 60 of potentiometer 26.
  • the potentiometer body 26 is supported by a carrier 73 of insulating material. Also secured thereto, by means of a support 74, is the contact device 63.
  • the shaft also carries the rotary contact 27.
  • the contact 27 and the switching arm 72 are pinched in position between small press plates 75 so as to be moved due to friction when the shaft 60 rotates, but they may alternatively be checked while the shaft keeps rotating.
  • the rotary contact 27 is stopped by an abutment 76, which is rotatably secured to the support 73 for the resistor body 26. The point Where the movement of the rotary contact terminates is thus adjustable.
  • the switching arm 72 If the switching arm 72 then has not reached the switch ing-ofif contact 65, it continues its movement and a constant tube voltage is supplied to the X-ray tube during'the portion of the path described by the switching arm 72 after the movement of the contact 27 has been blocked. To enable displacement of the contact device 65, it is rotatably secured to the support 73 by means of a supporting member 77.
  • the support 74 for the contact device 63 may be secured to be displaceable along the periphery of the support 73 so as to permit adjustment of the tube voltage at which the photographing process begins.
  • a rotary'contact'and means electrically connecting said resistance between said primary winding and said first switch means through said rotary contact in a manner whereby when said-first switch means is closed and the said rotary contact is at the beginning of its cycle of rotation a maximum value of said resistance is connected between the said primary winding and the said first switch means and rotation of the said rotary contact .reducespsaid resistance value to a minimum upon termination of the cycle of rotation, means for varying said minimum andmaximum magnitudes of voltage comprising a first movable pin abutment positioned at the beginning of the cycle of rotation and electromagnetic means actuated by the start of said time of exposure for moving said first pin out of the path of rotation of said rotary contact in a manner whereby the said rotary contact is per-mitted'to' initiate the cycle of rotation at said start of said time of exposure and a second movable-pin abutmentpositioned 'at the end of the cycle of rotation andrelectrornagnetic means actuated by the end o't'said time
  • a voltage regulating circuit arrangement for an X- ray tube having an anode and a cathode, said X-ray tube being adapted to operate at a desired operating voltage dependent upon the characteristics of an object .to be X-ray-photographed during the time of exposure required for the X-ray photograph, said desired operating voltage having a value in a range of voltages from a minimum voltage magnitude to a maximum voltage magnitude,.comprising means for applying a voltage .across 'said X-ray tube, said voltage applying means comprisingra high voltage transformer having a primary winding and a secondary winding connected between the anode and cathode ofsaid X-ray tube, first switch vmeans and means for applying a voltage across said primary winding through said first switch means, means .for automatically varying thevoltage across said X-ray tube from said minimum magnitude to said maximum magnitude during said time of exposure, said voltage varying means comprising arotary type :resistor having a resistance interposed betweens
  • first switchmeans and means for applying a voltage across said primary winding through said first switch means means for automatically varying the voltage across said X-ray tube from said 9 minimum magnitude to said maximum magnitude during said time of exposure
  • said voltage varying means comprising a rotary type resistor having a resistance interposed between said primary winding and said first switch means, a rotary contact and means electrically connecting said resistance between said primary winding and said first switch means through said rotary contact in a manner whereby when said first switch means is closed and the said rotary contact is at the beginning of its cycle of rotation a maximum value of said resistance is connected between the said primary winding and the said first switch means and rotation of the said rotary contact reduces said resistance value to a minimum upon termination of the cycle of rotation, means for varying said minimum and maximum magnitudes of voltage, means actuated by closure of said first switch means for rotating said rotary contact through the cycle of rotation from said maximum resistance value to said minimum resistance value

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • X-Ray Techniques (AREA)
US796925A 1958-03-11 1959-03-03 X-ray device Expired - Lifetime US3027460A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US163002A US3164723A (en) 1958-03-11 1961-11-09 Voltage regulating circuit for x-ray tubes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL225734A NL97148C (nl) 1958-03-11 1958-03-11 inrichting voor het maken van roentgenfotos , waarbij de buisspanning tijdensde opname automatisch wordt verhoogd

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US3027460A true US3027460A (en) 1962-03-27

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US796925A Expired - Lifetime US3027460A (en) 1958-03-11 1959-03-03 X-ray device

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US (1) US3027460A (nl)
CH (1) CH373476A (nl)
DE (1) DE1126526B (nl)
FR (1) FR1221302A (nl)
GB (1) GB908535A (nl)
NL (1) NL97148C (nl)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3403256A (en) * 1964-12-16 1968-09-24 Hoekstra Gerrit David Atse Method and apparatus for making an x-ray exposure on a photographic film with x-ray tube control
US3469100A (en) * 1967-02-16 1969-09-23 Westinghouse Electric Corp Motor-operated rotary input tap selector switch to regulate line voltage in x-ray system
US4087728A (en) * 1976-11-24 1978-05-02 Honeywell Inc. Adjustable stroke electric motor using stroke adjusting linkage means

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1236669C2 (de) * 1965-09-21 1973-10-25 Drehstrom - roentgendiagnostikapparat

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2036072A (en) * 1932-11-01 1936-03-31 Wappler Electric Company Inc Dosimeter
US2617047A (en) * 1948-09-30 1952-11-04 Hartford Nat Bank & Trust Co X-ray apparatus
US2786949A (en) * 1953-12-14 1957-03-26 Cormack E Boucher Controlled voltage system for X-ray tube units
US2883554A (en) * 1953-06-04 1959-04-21 Land Air Inc Control means for regulating the output of x-ray apparatus
US2936376A (en) * 1956-10-31 1960-05-10 Nl Rontgen App Nfabriek Nv Installations for making X-ray photographs

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE294829C (nl) *
US1972159A (en) * 1931-11-20 1934-09-04 Westinghouse X Ray Co Inc Method and apparatus for controlling x-ray intensity
DE893383C (de) * 1941-01-25 1953-10-15 Siemens Reiniger Werke Ag Einrichtung zur Bestimmung der guenstigsten Aufnahmespannung fuer Roentgenaufnahmen

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2036072A (en) * 1932-11-01 1936-03-31 Wappler Electric Company Inc Dosimeter
US2617047A (en) * 1948-09-30 1952-11-04 Hartford Nat Bank & Trust Co X-ray apparatus
US2883554A (en) * 1953-06-04 1959-04-21 Land Air Inc Control means for regulating the output of x-ray apparatus
US2786949A (en) * 1953-12-14 1957-03-26 Cormack E Boucher Controlled voltage system for X-ray tube units
US2936376A (en) * 1956-10-31 1960-05-10 Nl Rontgen App Nfabriek Nv Installations for making X-ray photographs

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3403256A (en) * 1964-12-16 1968-09-24 Hoekstra Gerrit David Atse Method and apparatus for making an x-ray exposure on a photographic film with x-ray tube control
US3469100A (en) * 1967-02-16 1969-09-23 Westinghouse Electric Corp Motor-operated rotary input tap selector switch to regulate line voltage in x-ray system
US4087728A (en) * 1976-11-24 1978-05-02 Honeywell Inc. Adjustable stroke electric motor using stroke adjusting linkage means
FR2372543A1 (fr) * 1976-11-24 1978-06-23 Honeywell Inc Moteur electrique a course reglable

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GB908535A (en) 1962-10-17
FR1221302A (fr) 1960-06-01
NL97148C (nl) 1961-02-15
DE1126526B (de) 1962-03-29
CH373476A (de) 1963-11-30

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