372596199

198 T. Nishidono et al.

198 T. Nishidono et al.

(a) (x 62.5)

To investigate the relationship between the seal-ing mechanism and geometry of a knife edge, we photographed the cross-sectional view of a cut sam-ple of fastened type A flanges (see Fig. 3.). The sample was fabricated by the process as shown in Fig. 2. Figurę 3 shows that only the top area of a knife edge touches to a gasket. Improvement to be touched over the whole area is required. Moreover we are still inspecting the same items on the type B flange.

(b) (x 125) .

Finally, materials of the flange, bolt, and gasket, and the geometry of a knife edge are very impor-tant factors for high vacuum sealing.

References

1) T. Nishidono, S. Yokouchi, Y. Morimoto, Y. Sakamoto, Y.P. Lee, and S.H. Be: J. Vac. Soc. Jpn., 33, 241 (1990).

Fig. 3. Cross-sectional views of fastened type A flange.