Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Quality evaluation
Reexamination Certificate
2001-09-25
2003-10-07
Barlow, John (Department: 2863)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Quality evaluation
C702S057000, C702S064000, C702S065000, C702S115000, C702S128000, C331S00100A, C331S00100A, C331S017000, C204S298030, C204S298080, C204S298340, C204S192150, C204S192220, C204S192380
Reexamination Certificate
active
06631336
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention concerns, in general, a nondestructive method of production quality control of high-voltage systems (HV systems).
HV systems such as HV generators and X-ray tubes, the service voltages of which can reach values of 100 kV or more, are becoming more and more compact and more and more powerful. These systems therefore release more and more heat, but the electric field density also increases and the operating safety margins of these devices are becoming ever narrower.
The active elements of these HV systems are insulated from one another by dielectric materials and, in particular, by dielectric liquids such as oils. The presents of pollutants in these dielectric materials, oils in particular, are harmful to the insulating qualities of these materials, which is translated on operation of the systems by discharges in these dielectric materials that can result, on subsequent use of these devices, in permanent damage to the systems. The risk of a high-voltage failure of the insulating materials of these systems to the point of permanent damage is direct related to the levels of pollution of the insulating materials after manufacture and, consequently, the rate of discharges likely to occur on subsequent use of the systems.
In HV systems, such as HV generators and X-ray tubes, the high-voltage components of the systems are generally insulated by a dielectric insulating liquid such as an oil, which also serves the function of cooling fluid.
The presence of pollutant in that oil creates, on operation of those systems, electric discharges which can reach the point of permanent damage of the device.
Although these electric discharges can appear in parts of the system other than the insulating liquid, they mainly occur in that liquid, for that liquid is the one most easily polluted in the course of the manufacturing process.
BRIEF DESCRIPTION OF THE INVENTION
The invention concerns, in particular, a nondestructive method of quality control of high-voltage systems, making it possible to quantify the residual level of discharges of a finite HV system.
The invention likewise concerns, in particular, a control method, such as indicated above, making it possible to ensure that HV systems of new design and reduced dimensions also present sufficient operating safety margins.
The invention also concerns, in particular, a method of control suited to final control of the HV systems manufactured, making it possible to select durable high-quality products, while reducing the costs of retreatment of products considered defective.
The invention finally concerns, in particular, a device for use of the above-mentioned method.
In one embodiment of the invention, a nondestructive method of quality control of the production of HV systems comprises:
(a) determining for each type of high-voltage system of a scale of values representing the energy of the radio-frequency (RF) spectrum transmitted by radio wave over a given period by the electric discharges appearing in the system for a given test voltage, by artificially varying in the system the level of pollution of the system until dielectric failure of the system;
(b) choosing on the scale of a limiting value embracing the admissible pollution tolerances on manufacture;
(c) measuring for each system of the same product type of the quantity of energy of the RE spectrum transmitted by radio wave by each of the systems under the same conditions as in stage (a); and
(d) comparing of the quantities measured in stage (c) with the limiting value chosen to determine a possible fluctuation of quality of the systems produced.
A nondestructive method of quality control of the production of high-voltage systems can comprise the following steps:
(a) determining for each type of high-voltage system of a scale of values representing the energy of the radio-frequency (RF) spectrum transmitted by radio wave over a given period in the electric discharges appearing in the system for a given test voltage, by artificially varying in the system the level of pollution of the system until dielectric failure of the system;
(b) measuring for each system of the same product type of the quantity of energy of the radio-frequency spectrum transmitted by radio wave by each of the systems under the same conditions as in stage (a); and
(c) comparing of the quantities measured in stage (b) with a limiting value chosen to determine a possible fluctuation of quality of the systems produced.
A device making it possible to use such a method for measurement of the energy of the RF spectrum transmitted by the discharges being established in the HV system comprises:
(a) an antenna that can be coupled to an HV output of the high-voltage system and which transmits RF signals representing the discharges being established in the high-voltage system when the latter is fed with a given test supply voltage;
(b) an adapted RF receiver receiving the signals transmitted by the antenna and delivering output signals; and
(c) device coupled to the receiver receiving the output signals from the receiver and supplying a signal representing the quantity of energy of the RF spectrum transmitted by radio wave over a given period by the electric discharges appearing in the system for the given test voltage.
The antenna can be made in a high-voltage connector.
A device for measurement of the energy of the RF spectrum transmitted by the discharges being established in a high-voltage system in operation can comprise means for transmission of RF signals representing the discharges being established in the HV system means for an RF reception capable of delivering output signals and means for processing capable of supplying a value representing the energy of the RF spectrum transmitted by radio wave over a given period by the electric discharges appearing in the system for a given test voltage.
The means for processing can comprise a microprocessor, one or more memories, one or more control programs and a communication bus, so that a program stored in a memory can be executed by the microprocessor.
The invention also concerns a computer program comprising program code means for applying the steps of the method, when the program is operating on a computer.
The invention also concerns a support capable of being read by a device for reading program code means which are stored there and are suitable for use of the steps of the method, when the program is operating on a computer.
REFERENCES:
patent: 769649 (1980-10-01), None
Pat. Abs. of Japan, vol. 1999, No. 10; JP 11-142467, Aug. 31, 1999.
Barlow John
Cantor & Colburn LLP
Chaskin Jay L.
GE Medical Systems Global Technology Company LLC
Walling Meagan S.
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