1989 Volume 55 Issue 513 Pages 1271-1274
In order to clarify the sealing performance of seal-ring connections for API buttress thread casing, the effect of gasket compressibility on the leakage pressure was investigated with a newly designed fundamental leakage test apparatus. The height compressibility HR and area compressibility AR of the gasket were proposed as the sealing performance factors, because the gasket is plastically deformed by the thread and filled in the groove. As the HR and ARbecame larger, the sealing performance was increased by the higher pressure on the contact surface between the thread and the gasket. It is considered that the dimensions of API standard are determined to keep high sealing performance in consideration of tolerance.