Glass tube cracking, vacuum tube/transformer assembly.

摘要

At the General Electric Neutron Devices Department (GEND) several cracked tubes in a vacuum tube-transformer assembly (TTA) were observed during production. The incidence of cracking was not great but it justified a study to determine the cause of tube cracking. An assessment of the stress in an encapsulated vacuum tube-transformer assembly included: stress required to crack a tube, stress due to encapsulation, and stress due to temperature cycling. Both strain gage and photoelastic techniques were used for this stress analysis. Evaluation of the results indicated that a highly stressed tube cracked at either encapsulation or during temperature cycling. When cracking occurred as a result of encapsulation, the encapsulant was bonded to the transformer core.