METHOD AND APPARATUS FOR SEQUENTIAL REPLACEMENT OF X-RAY TUBE CATHODE EMITTERS
Publication Date: 2017-May-10
The IP.com Prior Art Database
A method and apparatus for sequential replacement of X-Ray tube cathode emitters comprises utilizing a bimetallic strip for enabling replacement of multiple emitters in a sequential manner.
The present disclosure relates generally to X-Ray generation, and more particularly to sequential replacement of X-Ray tube cathode emitters.
In conventional X-Ray systems, operation of the bearing at high temperatures and high loads (CT X-Ray systems) while under high vacuum limits the life of the X-Ray tubes. Recent advances in bearing design have, in some cases, resulted in significant extension of the operational life of the bearing, such that the bearing routinely outlives some other X-Ray tube components, which now limit the X-Ray tube’s life. In many cases, aside from the bearing, the cathode filament (or the “emitter”) limits the life of the X-Ray tube. Conventional X-Ray tube cathode emitters operate via thermionic emission, and are a consumable component and the material therein is used or "boiled" away until failure of the X-Ray tube cathode emitters. Once the emitter(s) fail(s), the X-Ray tube ceases to function, and the emitter(s) must be replaced in order to re-operationalize the X-Ray tube. The replacement of emitter(s) can be time consuming, resulting in many hours of down-time of the X-Ray tube, which may delay patient diagnosis, and may cost a facility operating such X-Ray systems significantly in downtimes. Further, limited access to multiple emitter geometries result in compromises with respect to imaging quality and component life.
Therefore, there exists a need for reducing the time for replacing emitters in X-Ray tubes.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic illustrating a generic X-Ray tube architecture.
FIGS. 2, 2.1 and 2.2, each is a schematic illustrating the X-Ray architecture of FIG. 1, modified to include 4 emitters.
FIG. 3 is a schematic illustrating a rotating component advanced by 45 degrees.
FIGS. 4, 4.1 and 4.2, each is a schematic illustrating a spring, a plunger and a bimetallic strip assembly added to the X-Ray tube architecture.
FIG. 5 illustrates a detail of the bimetallic strip assembly of FIGS. 4, 4.1 and 4.2.
FIG. 6 illustrates a 2D version of the teeth engagement.
The disclosure presents techniques that increase the effective operational life of an X-Ray tube cathode significantly, by successively replacing emitters, for example, after an emitter fails or for another reason, without requiring accessing the X-Ray tube physically to remove and replace an emitter. Furthermore, the method and apparatus described in this disclosure is not limited to successively replacing failed emitters, but can be used to alternate between 2 or more functional emitter geometries for various diagnostic imaging requirements. Often, different‑sized emitters are used to produce different characteristic focal spots (i.e. large and small) on the X-Ray tube target for distinct types of imaging, and such different-sized emitters are incorporated into a single X-Ray tube cathode structure. The abil...