JPS61109300A - X-ray high voltage generating device - Google Patents

Abstract

PURPOSE:To prevent bad influence of high voltage discharge upon an X-ray control device by connecting a filter circuit to each of the output part of a direct current signal proportional to the X-ray tube current in an X-ray high voltage generating device and the input part of said signal in an X-ray control device. CONSTITUTION:At the time that a high voltage discharge generates between the X-ray tube 12 in an X-ray device 3 and the housing of said device 3, the discharge current flows to an X-ray high voltage generating device 2 through the earth terminals EX and ET of the device 3. This high frequency discharge current is suppressed by a low pass filter 18 at the output side of a neutral point circuit allowing a direct current proportional to the X-ray tube current in the device 2 to flow out and the same low pass filter 19 as the filter 18 at the input circuit of an X-ray control device 1, into which said direct current power enters. Furthermore, the high input impedance of the amplifier 22 in the device 1 decreases discharge current flow into the device 1 and prevents malfunction and damage occurrence in the X-ray control circuit owing to the discharge.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an X-ray high-voltage device, and particularly to an improvement of its neutral point circuit, and is directed to reducing malfunctions of the control circuit of the X-ray control device during high-voltage discharge. The present invention relates to a high voltage device suitable for.

[Background of the invention]

FIG. 1 shows the configuration and neutral point circuit of a conventional X-ray high-voltage device powered by a single-phase commercial power source. As shown in the figure, a neutral point circuit is drawn into the X-ray control device 1 through the secondary side neutral point terminal N-NE of the main transformer 9, and the tube current needle 13 is caused to swing, or the tube current is When the current value is detected and exceeds a predetermined tube current value, an alarm 16 is used to issue an alarm.

However, in a neutral point circuit with such a configuration, when a high voltage discharges in the case of an X-ray tube device or high voltage generator, which is at ground potential, the current will be extremely large and large compared to the tube current that normally flows. A high-voltage discharge current with a high frequency flows through the ground terminal E to the neutral point circuit in the X-ray control device, which has the disadvantage of causing the control device control circuit to malfunction and destroying semiconductor elements. .

[Purpose of the invention]

As mentioned above, the object of the present invention is to prevent the adverse effects on the control circuits of the X-ray control device, etc. even if high voltage discharge occurs in the high voltage circuit of the X-ray high voltage generator, high voltage cable, and X-ray tube device. X by an improved neutral point circuit that does not affect
Our purpose is to provide line high voltage equipment.

[Summary of the invention]

The neutral point circuit is a part of the high voltage circuit, but since it is possible to measure the X-ray tube current at a potential close to OV, it is possible to connect the circuit directly to the control device and use it to display the tube current. Overcurrent detection is being performed. It is a matter of course that when a high-pressure discharge occurs, the discharge current tends to flow through a circuit whose impedance is as low as possible. Therefore, in the present invention, a neutral current detection point is provided on the high voltage generator side, and a signal proportional to the tube current is generated there. This output signal is guided to the X-ray control device through a filter made up of C and L, and an equivalent low-pass filter is provided at the input section of the X-ray control device. The filtering effects of these two filters can prevent high-pressure discharge noise from entering an electronic circuit such as an X-ray control circuit.

[Embodiments of the invention]

An embodiment of the present invention will be explained below with reference to FIG. Components having the same functions as those in FIG. 1 are given the same reference numerals. In FIG. 2, 1 is an X-ray control device, 2 is an X-ray high voltage generator, and 3 is an X-ray tube device. 4 is the power terminal,
5 is a power switch, 6 is a heavy-burning transformer that sets the tube voltage, 7
is the X-ray irradiation switch, 8 is the main transformer-top terminal, 9 is the main transformer, 10 is the high voltage rectifier, 11 is the high voltage plug, 12 is the X-ray tube, 13 is the tube current needle, 14 is the neutral point 16 is a detection circuit for detecting overcurrent, etc.; 17 is a resistor that generates a DC voltage proportional to the tube current, which is provided on the high voltage generator side; 18 is C, which is provided on the high voltage generator side; The L filter 19 is a CL filter provided on the X-ray control device side, and is composed of a choke coil 20 and a capacitor 21 as shown in FIG.

Reference numeral 22 denotes an amplifier having a sufficiently larger input impedance than the detection resistor 17, such as a voltage follower.

The flow of the discharge current when a discharge occurs in the secondary side high voltage circuit in the X-ray high voltage apparatus configured as described above will be explained.

For example, when the anode side of the X-ray tube 12, which is the high-voltage positive electrode e side, discharges into the X-ray tube device 3, which is the housing, it flows through the ground terminal Exf to the ground terminal ET of the X-ray high voltage generator 2, and the tube current rectifier 14 to the ■ side coil of the main transformer 9.

In addition, when the filament of the X-ray tube 12, which is the high-voltage negative electrode e side, discharges into the X-ray tube device 3, which is the housing, the resistor 1 is discharged from the negative electrode e side coil of the main transformer 9 through the rectifier 14.
7 through the ground terminal ET of the X-ray high voltage generator 2
A discharge current flows to the ground terminal Ex of the wire tube device 3.

In this case, since the discharge current having a higher frequency component than the X-ray tube current is suppressed by the low-pass filter 18, 19, the input impedance of the amplifier 22 is sufficiently large, so the X-ray controller Naturally, the amount flowing into the first side is small, and malfunctions of the control circuit, destruction of semiconductor elements, etc. are prevented.

The features of the filter circuit are that the signal line side a,
The choke coil 20 is connected to the image line a', the signal reference line side, and b/.

This filter passes DC components and suppresses high frequency components such as noise, so it does not affect tube current signals close to DC.

The embodiments described above are details of an X-ray high-voltage device that uses a single-phase power source, but a high-voltage device that uses a three-phase power source and a storage battery as a power source converts direct current to alternating current to generate X-ray high voltage. The X-ray high-voltage device that generates the same effect also has the same effect.

〔Effect of the invention〕

According to the present invention, the neutral point circuit of the X-ray high-voltage device is separated into the high-voltage generator side and the X-ray control device side against high-voltage discharge noise, and the high-voltage generator, high-voltage cable, Even if a high voltage circuit such as a Xi tube device generates a discharge,
The noise may cause the control circuit of the X-ray control device to malfunction or cause abnormal
Radiation radiation or interruption of X-ray photography can be prevented.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an X-ray high-voltage device using a conventional single-phase commercial power supply as a power source, FIG. 2 is a block diagram of an X-ray high-voltage device according to an embodiment of the present invention, and FIG. 3 is a block diagram of a C , L filter circuit diagram. 9... Main transformer, 14... Rectifier, 17... X-ray tube current detection resistor, 18.19... C, L filter, 2
0... Choke coil, 21... Capacitor, 22
···amplifier.

Claims (1)

[Claims] 1. In an X-ray high-voltage device consisting of an X-ray high-voltage generator and an X-ray controller, the neutral point circuit on the X-ray high-voltage generator side generates a DC signal proportional to the X-ray tube current. A tube current signal receiving circuit is provided on the X-ray control device side, having a filter circuit connected to the output part of the signal generating circuit, and having a filter equivalent to the filter in the input circuit. X-ray high voltage equipment.