SU1172097A1 - X-ray unit - Google Patents

Abstract

X-RAY DEVICE, containing an X-ray tube, a high-voltage supply circuit connected to it with a setpoint device and anode voltage regulator, a glowing voltage circuit with setpoint device and a current regulator, the mAs relay, which is different in that permissible modes of the x-ray tube, the apparatus is additionally introduced a circuit for determining the anode power, a block for determining the power of the heat, a scaling unit and a block for selecting the maximum value to the inputs of which are connected an anodic power determination unit and a power generation unit, one of these circuits is connected to a selection unit of the maximum magnitude through a scaling unit, the output of which is connected to the controller of the voltage circuit, i the setting unit is permanently set to a fixed setpoint (L heating voltage corresponding to the point from the transition from the maximum permissible heating power to the maximum permissible anode power at the anode voltage value for a given tube.

Description

one ,

The invention relates to X-ray technology, and more specifically to X-ray machines with high voltage setting systems, heating voltage and milliamlecond relay (mAs).

The purpose of the invention is to ensure the operation of the apparatus only on the maximum allowable modes of the x-ray tube.

FIG. 1. Is a diagram of the x-ray apparatus in FIG. 2, a curve of operating modes of the x-ray tube;

The X-ray unit contains an X-ray tube ... 1 to which a high-voltage supply circuit with an adjustable source 2 of anode voltage is connected, set by sensor 3 and sensor 4 (measuring divider) of anode voltage. To the filament of the x-ray tube 1 is connected. The filament voltage circuit with an adjustable filament current source 5 and the setter 6j KOTopbBi is permanently set to a fixed filament voltage setting. I

The device also contains a sensor 7

a1ud - th current, block 8 for determining the power of the heat, multiplication unit 9, to the inputs of which the sensor 4 and 7 of the anode voltage of the anode power are connected, scaling unit 10 to the Olok 11 for selection of the maximum value, to the inputs of which is connected; block 8 HS through the tO block scaling, block 9 multiplication The output of block 11 is connected to the input of the adjustable source 5 of the filament current. The relay kAc of the device contains the source of the reference voltage 12 (IOI) and is controlled by an in. T grator 13 connected to the inputs of the comparator 14, the output of which includes the RS flip-flop 15, the output connected to the switching inputs of the sources 2 and 5 of the anode voltage and current, To the input of the integrator 13 anode current sensor 7 is connected.

The apparatus works as follows. In FIG. 2 shows the maximum allowable volt-ampere characteristic of the x-ray tube. In the range of the anodic voltage from zero to the tube current increase is limited by the permissible power, the perceived filament filament of the x-ray tube (filament power), and

720972

range from U to U - power; x-ray tube anode-dissipated (anode power).

Stabilizing the anode voltage 5 and the tube filament in general does not ensure the constancy of its anode current. Due to the change in the emissivity of the filament, the formation of a charge on the glass of the tube and the change in

At its vacuum, the tube current may vary. Therefore, in X-ray machines, stabilization is applied not of the tube filament, but of its anode current. At the same time on small anode settings

S5 voltage and large values of the anode current may exceed the permissible power at the incandescent and the tube may fail due to burnup of the filament. At high voltage and current settings, it is possible to exceed the anode power of the anode and the tube to fail due to melting of the anode in the focal spot area. For the above reasons in x-ray.

25 X-ray tubes are operated in modes that are far from those determined by its maximum permissible current-voltage characteristic, which reduces the performance of X-ray inspection.

When i and the device is turned on, the S input) b - trigger 15 receives a pulse that sets a signal at its output

35 Log. 1. This signal, coming to the switching inputs of adjustable sources 2 and 5 to the control input of the integrator 13, includes them. The voltage at the output of the controlled source 2 is determined by the value of the setpoint of the setting device 3. The stabilization of the anode voltage on the tube 1 is carried out but the magnitude of the feedback voltage taken from the output

 measuring divider 4 and an adjustable source 2 of anode voltage supplied to the corresponding input. At the output of the sensor 7 anode current connected to the second

50 by the input of the multiplication unit 9, the voltage value is proportional to the anode current value. The first input of block 9 is supplied with voltage from the output of measuring divider 4,

55 is the proportional value of the anode voltage. Therefore, the voltage at the output of block 9 is proportional to the anode power of the x-ray tube 1.

The block 8, connected to the output of the adjustable current source 5, serves to measure the power of the X-ray tube 1. In the amplitude control method, the block 8 is a peak detector, and in the pulse-pulse method - an integrating element The voltage at the output of block 8 is proportional power filament.

The scaling unit 10, which is turned on at the output of block 9, is a resistive voltage divider, which is calculated so that the voltage at the inputs of the maximum size selection unit 11 is equal to each other when the anode voltage on tube 1 is equal to and (Fig. 2). Block 11 is an diode-resistive OR circuit and the voltage at its output is equal to the maximum –y of the input voltages. From the output of block 11, the signal is fed to the feedback input of an adjustable source of heat current 5, which stabilizes the mode. At voltages lower than and,, in the apparatus as a whole, the power of the filament of X-ray tube 1 is stabilized, and at voltages greater than and. - anode power. At the same time, at voltages lower than U, the tube filament voltage is stabilized and the adjustable source 5 processes the signal from the unit for determining the power of the filament. At voltages of high, the controlled source 5 processes the signal of the anodic power, which exceeds the setting of the setpoint 6 at the maximum power of the filament

the result is a decrease in the filament current and, accordingly, the anode current until the signal from the output of block 11 becomes equal to the setpoint of the setpoint 6. Thus, in any case, the device operates at the maximum permissible tube current at a given voltage.

Since the current at a given voltage is not known in advance and can vary in the course of work in general delays, it becomes impossible to set the amount of time in advance. Therefore, the exposure task is performed not by separately specifying the current and time, but by setting the exposure in integral form in milliampere-seconds. For this, the voltage from the output of the sensor 7 of the anode current is fed to the input of the controlled inter- erator 13, from the output of which the voltage characterizing the magnitude of the exposure is fed to the first input of the comparator 14. The second input of the comparator 14 is supplied with the voltage ION 12 proportional to the required value exposure. With equal voltages at its inputs, the comparator 14 generates a Log signal at its output. 1, which, entering the R-input of the iib-trigger 15, transfer it. At the output of the CK-flip-flop 15 a Log signal is generated. O, which turns off regulated sources 2 and 5 and zeroes a managed integrator 13.

Thus, the proposed technical solution allows the maximum use of the capabilities of the X-ray tube, completely eliminating unacceptable modes of its operation.

Claims (1)

X-ray apparatus, containing an x-ray tube, a high-voltage power circuit connected to it with a setpoint and anode voltage regulator, a filament voltage circuit with a setpoint and incandescent current regulator, a mAc relay, characterized in that, in order to ensure operation of the apparatus only at maximum permissible x-ray tube conditions , an anode power determination circuit, a glow power determination unit, a scaling unit and a maximum value selection unit, to the inputs of which a circuit is connected, are additionally introduced into the apparatus determination of the anode power and a heating power determination unit, one of these circuits being connected to the maximum value selection unit via a scaling unit, the output of which is connected to the filament voltage circuit regulator, the setter of which is constantly set to a fixed set of incandescent voltage corresponding to the transition point from the maximum allowable power glow to the maximum permissible anode power at the anode voltage determined for a given tube. (rig. 1 1 1172097 2