JP2000215997A - X-ray generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve serviceability by specifying a portion where a high-voltage discharge occurs in an X-ray generator. SOLUTION: In this X-ray generator wherein an X-ray tube 2 is connected to a high-voltage generator 1 through a cable 3, a first current detecting resistor R2 is connected in series in an anode circuit of the X-ray tube 2, while a second current detecting resistor R1 is connected in series in a secondary circuit of the high-voltage generator 1. Comparison circuits respectively compare outputs of the first and second current detecting resistors R2, R1 with prescribed threshold values. Thereby, when a high-voltage discharge occurs, a portion where the discharge occurs can be discriminated the inside of the X-ray tube 2 from the other portion to be specified it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray generator capable of specifying and detecting a high-voltage discharge site.

[0002]

2. Description of the Related Art An X-ray apparatus or an X-ray CT apparatus is used not only for medical treatment but also for industrial use, and these apparatuses are provided with an X-ray generator. FIG. 4 shows a conventional X-ray generator very simply, in which the anode of a high-voltage generator 1 is grounded via a resistor R1, and the cathode of an X-ray tube 2 whose anode is grounded is connected to a high voltage source. The configuration is connected to the cathode of the high voltage generator 1 via the cable 3. Here, the resistor R1 is provided for detecting a tube current flowing through the X-ray tube 2. By taking out the voltage drop of the resistor R1 from the terminal A, the resistor R1 is connected between the anode and the cathode of the X-ray tube 2. While detecting the tube current flowing between the X-ray tube 2
The discharge current when a discharge occurs inside the X-ray tube can be detected. Therefore, when the discharge of the X-ray tube 2 is detected based on the signal from the terminal A, although not shown, the interlock The X-ray tube 2 is protected by stopping the generation of the high voltage. Note that the voltage generator 1 is represented by a battery symbol for simplification of the figure. However, the voltage generator 1 is usually one that rectifies a high AC voltage with a rectifier to obtain a high DC voltage, or a power supply that uses a high-frequency inverter. It is often. X-ray tube 2
The anode of the X-ray tube 2 is also connected to the anode of the high-voltage generator 1 through the high-voltage cable 3. Side will be connected.

[0003]

However, the high voltage discharge is not limited to the inside of the X-ray tube 2 and the high voltage generator 1 or X
It often occurs in the housing part (Haube) of the X-ray tube 2 and at the ends at both ends of the high-voltage cable 3. In particular, the X-ray tube 2 often becomes unstable and discharges. Since all the current flows through the resistor R1, it was not possible to specify the discharge site from the signal taken out from the terminal A. By the way, when the X-ray tube 2 generates a discharge inside, the X-ray tube 2 can be used again by aging the X-ray tube 2 for a while. On the other hand, when a discharge occurs at the high voltage generator 1 or at the end of the high voltage cable 3, it is necessary to repair by applying an insulating agent such as silicone grease to the discharge location. This is because, in the high-voltage generator 1 or the terminal portion of the high-voltage cable 3, if a discharge is repeatedly generated at the same location many times, irreparable fatal injury may occur. Therefore, conventionally, the discharge current of the high-voltage generator 1, the X-ray tube 2, the high-voltage cable 3 and the like can be taken out only from the terminal A of the resistor R1 for detecting the tube current. In this case, it was not possible to determine where in the high-voltage generator 1, the X-ray tube 2, and the high-voltage cable 3 occurred. For this reason, there have been problems such as delaying recovery of the device and inability to provide prompt service.
The present invention has been made to solve such a problem.

[0004]

According to a first aspect of the present invention, a high voltage generator and an X-ray tube connected to the high voltage generator via a cable are provided. An X-ray generator having a first current detecting means connected in series to the anode circuit of the X-ray tube and detecting only a tube current of the X-ray tube; and a series connected to a secondary circuit of the high voltage generator. A second current detecting means for detecting a secondary side current of the high voltage generator including the tube current, and outputting respective outputs of the second current detecting means and the first current detecting means to a predetermined current; And a comparing means for comparing with a threshold value. As a result, the tube current of the X-ray tube can be clearly measured, and when a high-voltage discharge occurs, the site of occurrence can be distinguished between the inside of the X-ray tube and other portions, and thereafter, Can be promptly dealt with. According to a second aspect of the present invention, there is provided an X-ray generator having a high-voltage generator and an X-ray tube connected to the high-voltage generator via a cable, wherein an anode circuit of the X-ray tube is provided. A first current detecting means connected in series and detecting only a tube current of the X-ray tube, between a storage portion of the X-ray tube and ground, and between an iron core of the high voltage generator and ground. A second current detecting means for detecting a high-frequency current at each part connected to at least one place between the coating of the cable and the ground; and a second current detecting means and the first current detecting means. Comparing means for comparing each output of the means with a predetermined threshold value. Thereby, the tube current of the X-ray tube can be clearly measured, and when a high-voltage discharge occurs, the generation site is set to the inside of the X-ray tube, the storage portion of the X-ray tube, a high-voltage generator, a cable, and the like. Can be subdivided and specified, and the subsequent response can be performed more quickly.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an X-ray generator according to the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an embodiment of the X-ray generator according to the present invention.
FIG. 2 is a circuit diagram that is extremely simplified. That is, FIG.
In FIG. 4, the configuration in which the anode of the high voltage generator 1 is grounded via the resistor R1 and the cathode of the X-ray tube 2 is connected to the cathode of the high voltage generator 1 via the high voltage cable 3 is shown in FIG. However, the present invention is different in that a second resistor R2 is connected in series between the anode of the X-ray tube 2 and the ground. Note that, for simplification of the drawing, the high-voltage generator 1 is represented by a symbol of a battery. However, usually, the high-voltage generator 1 rectifies an AC high voltage with a rectifier to obtain a DC high voltage, or a high-frequency inverter. It is often the power source. Furthermore, although the anode of the X-ray tube 2 is shown in a grounded form, it goes without saying that there is also a neutral grounding type. In this case, the anode of the X-ray tube 2 is also connected to a high voltage via the high-voltage cable 3. It will be connected to the anode side of the voltage generator 1.

In the circuit configuration shown in FIG. 1, the normal tube current of the X-ray tube 2 flows through both the resistor R1 and the resistor R2, so that the voltage drop of the resistor R1 is taken out from the terminal A or the voltage of the resistor R2. The voltage drop can be detected by extracting the voltage from terminal B. However, since what is detected from the terminal B of the resistor R2 does not include, for example, a high-frequency component flowing from the high-voltage cable 3 to the ground, only the tube current of the pure X-ray tube 2 can be detected. That is, the X-ray tube 2
The discharge current when a high-voltage discharge occurs inside the battery is detected at both the terminals A and B. The discharge current generated in the high-voltage generator 1 and the housing of the X-ray tube 2 and also in the high-voltage cable 3 Discharge current flows only through the resistor R1 and does not flow through the resistor R2, and is detected only at the terminal A. From this, by knowing how the signals were detected at the terminals A and B, it is possible to determine whether the discharge has occurred inside the X-ray tube 2 or has occurred elsewhere. Can be distinguished. When a discharge is detected, although not shown, the high voltage generator 1 is interlocked to stop the generation of the high voltage, and the X-ray tube 2 and other components of the X-ray generator are stopped. Is designed to protect.

FIG. 2 is a block diagram showing an example of a discriminator for discriminating a discharge portion. That is, the signal detected at the terminal A shown in FIG.
1 and also detected at the terminal B shown in FIG. 1 is supplied to the second comparison circuit 12. The discharge current is
Since the pulse-shaped current has a peak value sufficiently larger than the normal tube current flowing between the anode and the cathode of the X-ray tube 2, these comparison circuits 11 and 12 are compared with the tube current of the X-ray tube 2. A reference voltage is set so that a sufficiently large value can be detected, and only a signal larger than the reference voltage is passed using the reference voltage as a threshold. That is, the signals detected at the terminals A and B are supplied to the comparison input terminals 13 and 14 of the comparison circuits 11 and 12, respectively, and a predetermined reference voltage 17 is supplied to the reference voltage terminals 15 and 16 of the comparison circuits 11 and 12. , 18 are compared with the signals supplied to the comparison input terminals 13 and 14, and when the level of the input signal is greater than the reference voltage,
A high-level output signal is obtained at each of the output terminals 19 and 20.
The output terminals 19 and 20 of the comparison circuits 11 and 12 are branched, and one is connected to the OR circuit 21 and the other is connected to the latch circuit 22. The output of the OR circuit 21 is supplied to an interlock circuit 23, and the output of the latch circuit 22 is supplied to a discrimination circuit 24.

Therefore, when a normal tube current is flowing through the X-ray tube 2, although signals are generated at the terminals A and B shown in FIG. Is at low level, the interlock circuit 23 does not operate, and no discrimination output is obtained in the discrimination circuit 24. Here, when a discharge occurs inside the X-ray tube 2, the discharge current flows through the resistors R1 and R2, so that signals are generated at the terminals A and B, which are sufficiently larger than the reference voltages 17 and 18. Yes, the comparison circuit 11,
High-level signals are obtained at output terminals 19 and 20 from 12. This signal is supplied to the OR circuit 21 and the latch circuit 22, respectively, and a high-level output is obtained from the OR circuit 21. The interlock circuit 23 is operated by this signal, and the high voltage generator 1 shown in FIG. Cut off.
At this time, the signals of the output terminals 19 and 20 of the comparison circuits 11 and 12 are supplied to the latch circuit 22, and the high-level signals of the output terminals 19 and 20 immediately before the operation of the interlock circuit 23 are output from the latch circuit 22. Since the signal is held, the discrimination circuit 24 discriminates the portion where the discharge has occurred based on this signal. That is, when a discharge occurs inside the X-ray tube 2, the discharge current flows through the resistors R1 and R2 and is detected at both the terminals A and B. If both outputs are at the high level, the determination circuit 24 determines that a discharge has occurred inside the X-ray tube 2,
This is indicated on a display not shown.

When a discharge occurs in the high-voltage generator 1 or the high-voltage cable 3 excluding the X-ray tube 2, the discharge current flows only through the resistor R1 and is detected only at the terminal A. If the output of the comparison circuit 11 is at a high level and the output of the comparison circuit 12 is at a low level,
In, it is determined that a discharge has occurred in other parts except the X-ray tube 2. After the interlock circuit 23 is operated and the high-voltage generator 1 is shut off, when a countermeasure is taken to restore the X-ray generator, the latch circuit 22, the interlock circuit 23, The determination circuit 24 and the like are reset. Although the description has been made mainly on the determination of the site where the discharge has occurred, since only the tube current of the X-ray tube 2 flows through the resistor R2, the signal of the terminal B is used to make the X-ray tube 2
Needless to say, only the tube current can be clearly measured.

By the way, in the circuit of FIG.
Although it was only possible to discriminate between the X-ray tube 2 and the other portion except for the X-ray tube 2, the circuit configuration shown in FIG. it can. That is, as a current detecting resistor corresponding to the resistor R1, a resistor R11 is provided between the iron core 1a of the high-voltage generator 1 and the ground, and a resistor R11 is provided between the housing 2a of the X-ray tube 2 and the ground. The resistor R12 is further provided with a resistor R13 connected between the coating 3a of the high-voltage cable 3 and the ground, and the other configuration is the same as that of FIG. Therefore, when a discharge occurs inside the X-ray tube 2, a signal is generated only at the terminal B, and when a discharge occurs in the high voltage generator 1, the discharge current is supplied to the resistor R.
11, a signal is generated only at the terminal A1, and when a discharge occurs in the storage part 2a of the X-ray tube 2, a signal is generated only at the terminal A2 because the discharge current flows only through the resistor R12. Further, when a discharge occurs in the coating 3a of the high-voltage cable 3, the discharge current flows only to the resistor R13, so that a signal is generated only at the terminal A3. Therefore, the terminals A1, A2, A3, and B are connected to the discriminator 10, and the terminals A1, A2, and A are connected to the discriminator 10 as described with reference to FIG.
3, by providing a comparison circuit corresponding to the signal obtained from B, comparing each with a predetermined threshold to take out a signal of a level equal to or higher than the threshold, and determining from which terminal the signal is obtained, The discharge site can be further subdivided and specified. Note that these resistors R11, R12, R1
3 may not be all connected, but may be connected only to a portion where discharge is particularly desired to be detected.

[0011]

As described above in detail, according to the first aspect of the present invention, in the X-ray generator, the tube current of the X-ray tube can be measured clearly and a high-voltage discharge occurs. In such a case, the location of the occurrence can be identified and distinguished between the inside of the X-ray tube and the other parts, so that subsequent actions such as inspection of defective parts, repair of malfunctions, and arrangement of repair parts can be performed quickly. Thus, the recovery of the device can be hastened. According to the second aspect of the present invention, the tube current of the X-ray tube can be clearly measured, and when a high-voltage discharge occurs, the generation site is set to the inside of the X-ray tube, It can be subdivided and specified into parts such as the storage unit, high voltage generator, high voltage cable, etc., and the subsequent response such as inspection of defective parts, repair of failure, arrangement of repair parts will be quicker, and serviceability will be improved. it can.

[Brief description of the drawings]

FIG. 1 is an extremely simplified circuit diagram showing an embodiment of an X-ray generator according to the present invention.

FIG. 2 is a block diagram showing an embodiment of a discriminator for discriminating a discharge site in the apparatus of the present invention.

FIG. 3 is a circuit diagram showing another embodiment of the X-ray generator according to the present invention.

FIG. 4 is a circuit diagram showing a conventional X-ray generation apparatus in a very simplified manner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High voltage generator 2 X-ray tube 3 High voltage cable 10 Discriminator 14, 15 Comparison circuit 23 Interlock circuit 24 Discrimination circuit R1, R2 Resistor

Claims (2)

[Claims] 1. An X-ray generator comprising a high-voltage generator and an X-ray tube connected to the high-voltage generator via a cable, wherein the X-ray tube is connected in series to an anode circuit of the X-ray tube. First current detection means for detecting only the tube current of the wire tube; and a secondary current of the high voltage generator including the tube current, which is connected in series to a secondary circuit of the high voltage generator. X comprising: a second current detecting means; and a comparing means for comparing each output of the second current detecting means and the first current detecting means with a predetermined threshold value.
Line generator. 2. An X-ray generator comprising a high-voltage generator and an X-ray tube connected to the high-voltage generator via a cable, wherein the X-ray tube is connected in series to an anode circuit of the X-ray tube. First current detecting means for detecting only the tube current of the X-ray tube, between the storage portion of the X-ray tube and ground, between the iron core of the high-voltage generator and ground, and furthermore, coating of the cable. A second current detecting means for detecting a high-frequency current of each part connected to at least one place between the first current detecting means and each of the outputs of the second current detecting means and the first current detecting means. An X-ray generator, comprising: comparing means for comparing with a threshold value.