Assembly for forming a ceramic arc discharge vessel and method of manufacture
View Patent ↗An assembly for forming a hollow, ceramic arc discharge vessel for high-intensity discharge (HID) lamps is described wherein a means for self-alignment of two molded sections is provided. In particular, the sealing surface of one section of the arc discharge vessel is provided with a convex surface and the sealing surface of the other section is provided with a concave surface. The radius of the convex sealing surface is smaller than the radius of the concave sealing surface so that the sections may self-align during joining, preferably without gas entrapment in the seal.
1. A method of making a two-piece hollow ceramic body comprising the steps of:
forming a first section with a first joining edge and a second section with a second joining edge, the first and second sections containing ceramic material and a binder material, the first joining edge having a convex sealing surface having a radius of curvature R 1 , the second joining edge having a concave sealing surface having a radius of curvature R 2 , wherein R 2 is greater than R 1 ;
simultaneously heating the sealing surfaces to cause localized melting of the binder material;
initially contacting the sealing surfaces to form an interface region; and
applying compression to the interface region to join the first section to the second section.
2. The method of claim 1 wherein the first and second sections have a wall thickness T in a region adjacent to the first and second joining edges, and R 1 is equal to 0.75T and R 2 is equal to T.
3. The method of claim 1 wherein the first and second sections are axially symmetric.