An important quality criterion of industrial X-ray inspection solutions is the highest possible degree of utilization of the imaging components. The duty cycle of the x-ray tube is determined by its maintenance cycles and filament life. X-RAY WorX and Gulmay have jointly tested the effects of Gulmay's newly developed filament supply for the high-voltage generators of the UC product family on the service life of X-RAY WorX's microfocus X-ray tubes.
The exact setting of the filament heating current has a significant influence on the life of the filament of an open microfocus X-ray tube. During operation, the thickness of the tungsten filament decreases, which increases the resistance of the wire. The X-ray tube's control software must regularly adapt the filament current to these changes.
Gulmay Ltd. has developed a new patented filament supply (AC resonant filament, ACRF) for its UC product family, which enables significantly higher accuracy in the control and monitoring of the filament current.
The new closed-loop output current control design results in a more stable behavior of the filament heating current with excellent linearity over the entire operating range of the filament. Mains or other low frequency interference associated with filament supply is significantly reduced. At the same time, the new primary current sensing circuitry enables very accurate output current monitoring without requiring measurement on the filament or within the high-voltage assembly.
To validate the actual effects of the new filament supply, X-RAY WorX performed a dynamic stress test using an XWT-225-THE Plus microfocus tube. This consisted of cycling at a voltage of 160 kV and 48 W target power for 10 minutes each, followed by a 4-minute period with the X-rays switched off. In addition, an automatic filament adjustment was performed once an hour.
The first series of tests with the original filament supply resulted in an average filament life of 310 hours. The second set of tests with the ACRF showed an average lifespan of 541 hours. The service life of the filament has thus increased by more than 70% in our laboratory tests.
X-RAY WorX will introduce the generators with ACRF filament supply for all product lines. For upgrading existing high voltage generators please contact your X-RAY WorX service department.
About Gulmay
With locations in the UK, USA, Germany and China, Gulmay is a leading manufacturer of high voltage generators and controls for industrial applications. With 40 years of experience developing microfocus X-ray generators, Gulmay continues to innovate new products that bring significant benefits to our OEM partners around the world.