Analysis of common faults in X ray tube
Fault 1: fault of rotating anode rotor
The circuit is normal, but the speed is obviously decreased, the time of static rotation is short, and the anode does not rotate when it is exposed.
When exposed, the tube current increases sharply, the fuse fuse breaks, and the anode target surface is melted.
After long-term work, the wear and deformation of the bearing and the change of the gap will change, and the molecular structure of the solid lubricants will be changed.
Fault two: damage of anode target surface of X ray tube
The output of X ray decreased significantly, and the sensitivity of X ray film was insufficient
As the anode metal is evaporated at high temperature, a thin layer of metal is deposited on the glass wall.
Through a magnifying glass, it can be seen that there are cracks, cracks and erosion on the target surface.
Tungsten metal splash when melting may cause serious focus X ray tube burst damage.
Overload use. There are two possibilities: one is overload protection circuit failure and one exposure overload; the other is multiple exposure, resulting in cumulative overload and melting evaporation.
The rotating anode X ray tube rotor block or start protection circuit fails, exposing to the anode without rotation or rotating speed, resulting in the instantaneous melting and evaporation of the anode target surface.
The heat dissipation is bad. Such as radiator and anode copper body contact is not close enough or too much grease.
Fault three: the opening of X ray tube filament
No X rays are produced during exposure, and there is no indication in miliampere meter.
The X - ray tube window can be seen that the filament is not bright; (3) measuring the X - ray tube filament, the barrier is infinite.
X - ray tube filament voltage is too high to burn off filament;
The vacuum of the X - ray tube is destroyed, and a large amount of intake makes the filament oxidize and burn quickly after the filament is electrified.
Fault four: NO x - ray failure in photography
There is no X-ray in photography.
If there is no X-ray in photography, it is usually first to judge whether the high pressure can be sent to the tube normally, directly in the light bulb.
The voltage is measured at the point. Beijing Wandong as an example, the general high voltage transformer primary voltage is 3:1000, of course, pay attention to the machine in advance leave space. This space is mainly due to internal resistance, such as power supply, autotransformer and so on. When the exposure is increased, the input voltage will decrease. This loss is related to the selection of Ma. The larger the Ma and the larger the loss, the higher the no-load detection voltage. Therefore, when the voltage measured by the maintenance personnel exceeds a certain range outside 3:1000, the value is also normal. The excess value is related to the selection of Ma, the larger the Ma is, the greater the value. It can be used to determine whether the high voltage primary circuit has a problem.