US3838285A
Expired / Lapsed
US
⏱️ 0.0 years remaining
X-ray tube anode protective circuit
Assignee: CGR Medical Corp
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Filing: 1973-05-10
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Granted: 1974-09-24
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Expires: 1993-05-10
Abstract
Abstract An X-ray tube protective circuit wherein the selected exposure time and X-ray tube power are compared prior to operation to determine whether or not a condition exists which exceeds the anode rating of the tube and thereafter prevents operation in the event that such condition does exists while permitting an X-ray exposure for a safe condition. The protective circuit utilizes a single empirically derived anode ''''rating chart'''' curve which is representative of a generalized or standard X-ray tube rating chart curve. This empirical curve is generated by a series connected string of resistors connected to the exposure time select switch. This curve is then tilted and/or offset for selected operating modes in order to substantially conform to the acual rating curve for the respective various focal spot sizes and anode speeds of the particular X-ray tube in use.
Inventors
- 👤 M Siedband
- 👤 J James
- 👤 A Patel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:59
CPC Classifications
H; H05; H05G; H05G1/00; H05G1/08; H05G1/26; H05G1/54
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
351 words
X-ray tube anode protective circuitry including circuit means being operated by the output of a comparator circuit which compares selected values of analog voltages representative of Xray tube rating chart curves for preventing energization of the X-ray tube in the event preselected operating parameters are outside of the ratings of the X-ray tube, comprising the combination of: a supply voltage; a single voltage divider network, for multiple operational modes having respective different rating chart curves for at least one X-ray tube, coupled across said supply voltage and having a current-voltage characteristic adapted to simulate a generalized rating chart curve which is a function of a plurality of exposure times and providing a plurality of voltage points corresponding to allowable peak power for said exposure times; first switch means having a movable contact and a plurality of fixed contacts respectively connected to said plurality of voltage points on said voltage divider; a voltage amplifier having an input and output and including circuit means coupling the output of said amplifier to the input of said comparator circuit; a plurality of first circuit means, each respectively adapted to vary the signal transfer characteristic of said voltage amplifier, selectively coupled between the input of said amplifier and the movable contact of said first switch means for each of said multiple operational modes whereby the output of said amplifier provides an output simulating the actual rating chart curve for the selected multiple operational mode; an X-ray anode supply voltage; a second voltage divider network coupled across said anode supply voltage and providing a plurality of voltage points proportional to the product of X-ray anode voltage and beam current of the X-ray tube; and second switch means having a movable switch contact and a plurality of fixed contacts selectively connected to said plurality of voltage points of said second voltage divider network and additionally including second circuit means coupling the movable contact of said second switch means to the input of said comparator circuit whereby the resultant voltage at said input of said comparator comprises a signal input which is a function of the preselected operating parameters.
Claim 2
Dependent Claim
351 words
X-ray tube anode protective circuitry including circuit means being operated by the output of a comparator circuit which compares selected values of analog voltages representative of Xray tube rating chart curves for preventing energization of the X-ray tube in the event preselected operating parameters are outside of the ratings of the X-ray tube, comprising the combination of: a supply voltage; a single voltage divider network, for multiple operational modes having respective different rating chart curves for at least one X-ray tube, coupled across said supply voltage and having a current-voltage characteristic adapted to simulate a generalized rating chart curve which is a function of a plurality of exposure times and providing a plurality of voltage points corresponding to allowable peak power for said exposure times; first switch means having a movable contact and a plurality of fixed contacts respectively connected to said plurality of voltage points on said voltage divider; a voltage amplifier having an input and output and including circuit means coupling the output of said amplifier to the input of said comparator circuit; a plurality of first circuit means, each respectively adapted to vary the signal transfer characteristic of said voltage amplifier, selectively coupled between the input of said amplifier and the movable contact of said first switch means for each of said multiple operational modes whereby the output of said amplifier provides an output simulating the actual rating chart curve for the selected multiple operational mode; an X-ray anode supply voltage; a second voltage divider network coupled across said anode supply voltage and providing a plurality of voltage points proportional to the product of X-ray anode voltage and beam current of the X-ray tube; and second switch means having a movable switch contact and a plurality of fixed contacts selectively connected to said plurality of voltage points of said second voltage divider network and additionally including second circuit means coupling the movable contact of said second switch means to the input of said comparator circuit whereby the resultant voltage at said input of said comparator comprises a signal input which is a function of the preselected operating parameters.
Claim 3
Dependent Claim
35 words
The protective circuitry as defined by claim 1 and additionally including switch means operable in conjunction with said second switch means, selectively coupling said plurality of first circuit means to the input of said amplifier.
Claim 4
Dependent Claim
27 words
The protective circuit as defined by claim 1 wherein each of said first circuit means includes means for selectively varying at least the gain of said amplifier.
Claim 5
Dependent Claim
59 words
The protective circuit as defined by claim 3 wherein said voltage amplifier comprises a feedback amplifier including an impedance coupled between its input and output, and said means for selectively varying the gain of said amplifier comprises a variable impedance coupled in series between the input of said amplifier and said movable switch contact of said first switch means.
Claim 6
Dependent Claim
40 words
The protective circuitry as defined by claim 4 and additionally including circuit means in each said first circuit means for providing a bias voltage to the input of said amplifier for further varying the signal transfer characteristic of said amplifier.
Claim 7
Dependent Claim
51 words
The protective circuitry as defined by claim 5 wherein said circuit means for providing a bias potential tO the input of said amplifier comprises a second supply voltage and a potentiometer coupled across said second supply voltage, said potentiometer including a movable voltage tap coupled to the input of said amplifier.
Claim 8
Dependent Claim
70 words
The protective circuitry as defined by claim 5 and additionally including third switch means ganged with said second switch means, having a movable switch contact and a plurality of fixed contacts selectively connected to said plurality of first circuit means for varying the signal transfer characteristic of said amplifier, said movable switch contact of said third switch means being connected to the movable switch contact of said first switch means.
Claim 9
Dependent Claim
70 words
The protective circuitry as defined by claim 7 and additionally including fourth switch means ganged with said second and third circuit means, having a movable switch contact and a plurality of fixed contacts selectively coupled to the opposite end of said first circuit means for varying the signal transfer characteristic of said amplifier, said movable switch contact of said fourth switch means being coupled to the input of said amplifier.
Claim 10
Dependent Claim
59 words
The protective circuitry as defined by claim 1 and additionally including first resistor means coupling the output of said amplifier to the input of said comparator and second resistor means coupling the movable switch contact of said second switch means to said input of said comparator, said first and second resistor means being coupled at a common junction thereat.
Claim 11
Dependent Claim
22 words
The protective circuitry as defined by claim 1 wherein said first and second voltage divider networks are comprised of resistor divider networks.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-23 | 1978-03-25 | 1978-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-23 | 1982-03-25 | 1982-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-23 | 1986-03-25 | 1986-09-24 | $7700.00 | Window Closed / Lapsed |