JPS63252396A - X-ray controller - Google Patents

Abstract

PURPOSE:To prevent the burnout of an X-ray tube filament by interlocking an X-ray irradiation switch in an open state with the output of a comparator which compares photographing tube current set voltage with photographing tube voltage set value proportional voltage when a photographing condition requires current exceeding the maximum allowable filament current. CONSTITUTION:An X-ray irradiation controller 9 which interlocks an X-ray irradiation switch in an open state with the output of a comparator which compares tube current set voltage with tube voltage set value proportional voltage when a photographing condition requires current exceeding the maximum allowable filament current is installed. When the voltage proportional to the tube voltage set value is lowered than the voltage corresponding to the tube current set value, the X-ray irradiation switch 7 is interlocked in an open state so that photographing is not conducted in this photographing condition. Since photographing is not conducted in the region within which current exceeds the maximum allowable filament current of an X-ray tube 5, the burnout of the filament of the X-ray tube 5 is prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a protection circuit for an X-ray tube in an X-ray apparatus, and particularly to an X-ray control device suitable for protecting an X-ray tube filament. be.

[Prior art]

Conventionally, general X-ray equipment other than microcomputer-controlled systems has been equipped with a protection circuit for the load rating of the anode, but this restricts imaging under imaging conditions that exceed the maximum permissible current of the X-ray tube filament. No means are provided.

[Problem that the invention seeks to solve]

In such general X-ray equipment, there is no means to restrict imaging under imaging conditions that exceed the maximum permissible filament current of the X-ray tube, so the imaging tube current (hereinafter simply referred to as tube current) is large. On the other hand, the tube current is not determined only by the filament current but is influenced by the tube voltage. , which shows the part limited by the maximum permissible filament current).

To obtain the same tube current, the lower the tube voltage, the more the filament current must be increased.

Therefore, under the imaging conditions of large tube current and low tube voltage, there is a problem in that the maximum permissible current of the X-ray tube filament is exceeded, and the X-ray tube filament may become disconnected.

Furthermore, when the X-ray tube filament becomes disconnected, high voltage is applied in a no-load state where no tube current flows.
There is a problem in that there is a risk of applying an abnormally high voltage to the X-ray tube device or high voltage generator. The present invention has been made to solve the above problems, and an object of the present invention is to detect when imaging conditions are set that exceed the XIAX X-ray tube filament large allowable current. The objective is to provide technology that can restrict photography.

The above and other objects and novel features of the present invention will be explained by the following description of the specification and the accompanying drawings.

[Means for solving problems]

A brief overview of typical inventions disclosed in this application is as follows.

That is, a tube current set value voltage generating circuit generates a voltage corresponding to the tube current set value, a tube voltage set value proportional voltage generating circuit generates a voltage proportional to the tube voltage set value, and a tube current set value voltage generating circuit that generates a voltage proportional to the tube current set value. A comparator that compares the proportional voltage of the tube voltage set value, and an X-ray irradiation controller that interlocks the X-ray irradiation switch to an open state when the imaging conditions exceed the maximum allowable filament current based on the output of the comparator. It is characterized by having the following.

[Effect]

According to the above, a voltage corresponding to a tube current setting value is generated,
Generates a voltage proportional to the tube voltage setting.

The tube current set value voltage and the tube voltage set value proportional voltage are compared by a comparator, and an xg irradiation switch is provided that applies a restriction when the imaging condition exceeds the maximum allowable filament current based on the output of the comparator. By providing an X-ray irradiation control means that interlocks in the open state, when the voltage proportional to the tube voltage setting value becomes lower than the voltage corresponding to the tube current setting value, the comparator detects, for example, +15
The volt (V) output changes to -15 volt output, detects this voltage level change, applies this changed voltage to the X-ray irradiation controller, and sets the X-ray irradiation switch to the open state. Since it is interlocked with the X-ray tube filament and limits the ability to perform imaging under the set imaging conditions, it is impossible to perform imaging under the imaging conditions that exceed the maximum permissible current of the X-ray tube filament, thereby preventing disconnection of the X-ray tube filament, etc. It is possible to provide protection such as preventing such accidents from occurring. This causes large tube current.

Under low tube voltage imaging conditions, there is no risk of exceeding the maximum permissible current of the X-ray tube filament and causing the X-ray tube filament to break, so set the imaging conditions without paying attention to the characteristics of the X-ray tube. Can be done.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be specifically described using the drawings.

Note that throughout the description of the embodiments, parts having the same functions are given the same reference numerals, and repeated explanations thereof will be omitted.

FIG. 1 is a circuit diagram showing a schematic configuration of an embodiment in which the present invention is applied to a single-phase X-ray device, and FIG. 2 is a circuit diagram showing a detailed configuration of the X-ray control device shown in FIG. 1. .

FIG. 3 shows the tube current set value voltage Va shown in FIG.

It is a graph when the imaging tube voltage (R-KV) of the tube voltage set value proportional voltage vb is changed.

In the single-phase X-ray apparatus of this embodiment, as shown in FIG. 1, AC voltage from a commercial power source 1 is applied to an autotransformer 2 that adjusts the primary voltage of a high-voltage transformer 3. This autotransformer 2
The output voltage is applied to the high voltage transformer 3 and transformed into a high voltage. The high voltage output from the high voltage transformer 3 is rectified by a high voltage rectifier circuit 4, converted into a DC high voltage, and applied to the X-ray tube 5. The filament of the X-ray tube 5 is heated by a filament heating circuit 6. The tube current flowing through the X-ray tube 5 and the resistance 6
The current flowing through A is approximately equal to the current flowing through A. Therefore, the voltage v11 of the resistor 6A is applied to the tube current
A multiplied by the resistance value R (V, = RI), and the voltage V corresponds to the tube current on a one-to-one basis. This voltage V is converted by the tube current detection circuit 6B into a signal level used in a control circuit inside the filament heating circuit 6, and is inputted to the filament heating circuit 6 as a tube current signal.

The filament heating circuit 6 uses the tube current signal inputted from the tube current detection circuit 6B and the filament heating circuit 6 in advance.
The filament heating power is adjusted so that the set tube current signal Is becomes equal to the set tube current signal Is. A thyristoruff is connected to the primary side of the high voltage transformer 3 as an X-ray irradiation switch for opening and closing X-ray irradiation. A gate signal generation circuit 8 that generates a gate signal for controlling the thyristor is connected to the control terminal of the thyristor.

In this gate signal generation circuit 8.

Output of the X-ray control device 19 for protection such as preventing the X-ray tube filament from breaking, etc. by disabling imaging in areas where the imaging conditions exceed the maximum permissible current of the X-ray tube filament. An interlock signal S is input.

The X-ray control device 9 is as shown in FIG.

A tube current set value voltage generating circuit 9A that generates a voltage corresponding to the tube current set value, and a tube current set value voltage that corrects this tube current set value voltage according to the characteristics of the X-ray tube 5 shown in FIG. The correction circuit 9B, the tube voltage set value proportional voltage generation circuit 9C that generates a voltage proportional to the tube voltage set value, and the tube current set value voltage and tube voltage set value corrected by the tube current set value voltage correction circuit 9B. a comparator 9D for comparing proportional voltages;
The output of this comparator 9D is used to limit X-ray irradiation by interlocking the thyristor (X, l irradiation switch) 7 in the open state shown in FIG. It consists of a controller 9E, etc.

As shown in FIG. 2, the tube current set value voltage generating circuit 9A includes fixed resistors 9A1, 9A, 9A3°9A, and variable resistors 9B, 9B, 9B, 9B.

Divide the constant voltage +15V by , and set each tube current value mA
, mA, , mA, y mA4 (see FIG. 3) is configured to set a corresponding tube current set value voltage. The tube current set value voltage corresponding to the set tube current is switched and outputted by the analog switch 9F. and.

The analog switch 9F is configured to switch each tube current according to a tube current switching signal Si.

The tube current set value voltage is amplified by a non-inverting amplifier 10, the gain of which is:

Adjustment is made using a fixed resistor 11 and variable resistors 13 and 14.

The tube current set value voltage correction circuit 9B includes a variable resistor 13.1 of the non-inverting amplifier 10 for each X-ray tube 5 (FIG. 1).
4 with an analog switch 12, the gain is changed to correct differences in characteristics of the plurality of X-ray tubes 5. And analog switch 1
2, the X-ray tube switching signal St is used to switch each tube.

The output of the non-inverting amplifier 10 is input to the negative input terminal of the comparator 9D, and the level of the tube current set value voltage is Va.

In addition, the tube voltage set value proportional voltage generation circuit 9C, which is made up of a variable resistor, divides the constant voltage +15 volts (V) to generate a tube voltage set value proportional voltage vb that is proportional to the tube voltage set value. It is designed to be input to the positive input terminal.

The comparator 9D compares the magnitudes of the input voltages Va and vb, and if vb is greater than Va, +Vc (for example, +15
Volt) is output, and when vb becomes smaller than Va, -V
c (-15 volts) is output.

The relationship between the tube voltage setting value (R-K V) and tube current setting value (m A11 m Az v m A32 m A4)
This is shown in Figure 3.

In FIG. 3, for example, the tube current set value voltage Va is mA
, when the tube voltage set value R-KV becomes smaller than 70 kilovolts (KV), the tube voltage set value proportional voltage vb
is smaller than the tube current set value voltage Va, and the output voltage Vc of the comparator 9D becomes 115 volts. Similarly, when the tube current setting value mA is 60 kilovolts (KV), when the tube voltage setting value R-KV is smaller than the respective tube voltage setting value R-KV, the output voltage Vc of the comparator 9D becomes -15V.

This relationship satisfies the conditions for limiting the imaging conditions under which the X-ray tube operates with space charges. In other words, when the output voltage Vc of the comparator 9D reaches -115V, it is restricted so that photography cannot be performed under that photography condition, and this fact is displayed. For example, although not shown, this display lights up an indicator light when the output voltage Vc of the comparator 9D reaches -15V.

That is, when the output voltage Vc of the comparator 9D reaches -15V, the X-ray irradiation controller (interlock signal generation circuit) 9E built in the gate signal generation circuit 8 generates an interlock signal. , and Thyristough is on (
ON) L is interlocked so that no photography is possible under the set photography conditions.

This prevents images from being taken in areas where the imaging conditions exceed the maximum permissible current of the X-ray tube filament, and protects the X-ray tube filament by preventing breakage of the X-ray tube filament, etc. can do. As a result, under imaging conditions of large tube current and low tube voltage, there is no risk of exceeding the maximum permissible current of the X-ray tube filament and causing the X-ray tube filament to break, so pay attention to the characteristics of the X-ray tube. You can set the shooting conditions without any hassle.

Although the present invention has been specifically explained above with reference to Examples, it goes without saying that the present invention is not limited to the above-mentioned Examples and can be modified in various ways without departing from the gist thereof. stomach.

〔Effect of the invention〕

As described above, according to the present invention, a voltage corresponding to the tube current setting value is generated, a voltage proportional to the tube voltage setting value is generated, and the tube current setting value voltage and the tube voltage setting value proportional voltage are generated. By providing an X-ray irradiation control means that interlocks the X-ray irradiation switch to the open state, which limits the imaging conditions that exceed the maximum permissible filament current by comparing the values with a comparator and using its output to limit the imaging conditions that exceed the maximum allowable filament current. When the voltage proportional to the tube voltage setting value becomes lower than the voltage corresponding to the tube current setting value, the comparator outputs, for example, +15 volts (V) until now, but changes to -15 volts. , detecting a change in this voltage level, and applying this changed voltage to the X-ray irradiation controller.

The X-ray irradiation switch is interlocked to the open state, and imaging is restricted under the set imaging conditions.
It is possible to protect the X-ray tube filament by preventing it from being photographed in a region where the photographing conditions exceed the maximum permissible current of the X-ray tube filament, thereby preventing breakage of the X-ray tube filament. Due to this.

Under the imaging conditions of large tube current and low tube voltage, there is no risk of exceeding the maximum permissible current of the X-ray tube filament and causing the xi tube filament to break, so the imaging conditions can be adjusted without paying attention to the characteristics of the X-ray tube. Can be set.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a schematic configuration of an embodiment in which the present invention is applied to a single-phase X-ray device, and FIG. 2 is a circuit diagram showing a detailed configuration of the X-ray control device shown in FIG. 1. , FIG. 3 shows the tube current set value voltage Va shown in FIG. It is a graph when the imaging tube voltage (■ to R-) of the tube voltage set value proportional voltage vb is changed. FIG. 4 is a characteristic curve diagram showing the tube current characteristics of the X-ray tube. In the figure, 1... commercial power supply, 2... autotransformer, 3...
・High voltage transformer, 4... High voltage rectifier circuit, 5... X-ray tube, 6... Filament heating circuit, F... Thyristor, 8... Gate signal generation circuit, 9... X Line control device, 9A... Tube current set value voltage generation circuit, 9B...
Tube current set value voltage correction circuit, 9C... Tube voltage set value proportional voltage generation circuit, 9D... Comparator, 9E... X-ray irradiation controller, 9F, 12... Analog switch, 10.
・・Non-inverting amplifier, 11・・Fixed resistance, 13.14・
...It is a variable resistance.

Claims (1)

[Claims] (1) A camera tube current set value voltage generation circuit that generates a voltage corresponding to the camera tube current set value, a camera tube voltage set value proportional voltage generator circuit that generates a voltage proportional to the camera tube voltage set value, and A comparator that compares the tube current set value voltage and the imaging tube voltage set value proportional voltage, and an output from the comparator that switches the X-ray irradiation switch to an open state when the imaging condition exceeds the maximum allowable filament current. An X-ray control device comprising: an X-ray irradiation controller that locks.