This paper deals with a new seal system between two flanges without using gaskets. The system includes a groove and an annular lip that is held by one of the flange with its highest point in contact with the other flange to form a seal line when the flanges are assembled. The condition whether the system leaks or not depends on the shape and dimension of the annular lip and its deformation during the contact. In this study, several gasketless flanges are prepared with different lip dimensions to investigate the contact and sealing condition through an experimental and FEM analyses. The analyses indicate that the conditions can be expressed in terms of the maximum contact stress and the plastic zone size when the flanges are assembled. The helium leak testing reveals that the gasketless flange has better sealing performance compared to conventional gaskets.

Home page, _caa.html
Jun Akagawa, 1972, Seal Technology, 365-369, Kindaihenshusha (in Japanese).
Nikkan-Kogyo Newspaper, Dec. 2. 1998, 37 (in Japanese).
Hiroshi Otsuji, and Nagawa, Masato, Japan patent no. 2849345 (in Japanese); Hiroshi Otsuji and Masato Nagawa, USA patent (soon to appear).
JIS Z 2331-1992 (Reaffirmed 1998), Method of Helium Leak Testing, Sniffer Method, pp. 17–20.
JIS B 2220, 1995, JIS B 2238, 1996.
JPI STANDARD, Pipe Flange for the Petroleum Industry (Addenda-96), JPI-7S-15-93 (Addenda-96).
You do not currently have access to this content.