Patent ID: 7744094

Claim:
A mechanical seal device, wherein a rotational seal ring and a stationary seal ring are arranged to face to each other between a rotational shaft and a housing fit together, comprising: the rotational seal ring connected to said rotational shaft, having a rotational seal surface, and having a plurality of arc-shaped grooves arranged on said rotational seal surface to be a circular shape around an axis center of said rotational shaft, the grooves being sectionalized by partition walls; the stationary seal ring having a stationary seal surface facing the rotational seal surface of said rotational seal ring; a bias means for pressing said stationary seal ring against said rotational seal ring; and outlet portions formed on said stationary seal surface of said stationary seal ring and capable of connecting with a fluid supply path for supplying a pressure fluid, wherein said arc-shaped grooves are arranged at positions facing said outlet portions formed on said stationary seal surface, wherein said outlet portions are arranged at positions forming a circle around the rotational shaft and having an identical radius that is concentric with said arc-shaped grooves, and wherein a circumferential direction length (W 3 ) of each of said outlet portions is made to be ½ of a circumferential direction length (W 1 ) of each of said partition walls or longer (W 3 ≧W 1 /2); the circumferential direction length (W 3 ) of each of said outlet portions is made to be shorter than a circumferential direction length (W 2 ) of each of said arc-shaped grooves (W 3 <W 2 ).