Patent ID: 8047231

Claim:
A valve element unit provided in a casing having a first opening and a second opening for closing the first opening and the second opening, comprising: a first valve element for closing said first opening, said first valve element being formed in a shape elongated in a longitudinal direction thereof, said first valve element including an arc shape portion at both end portions thereof in the longitudinal direction; a second valve element for closing said second opening, said second valve element being formed in a shape elongated in the longitudinal direction, said second valve element including a middle portion between both end portions thereof and a contracted arc shape portion at the both end portions in the longitudinal direction, said contracted arc shape portion having a width in a direction perpendicular to the longitudinal direction smaller than that of the middle portion in a direction perpendicular to the longitudinal direction; a first sealing member fit to the first valve element for airtightly sealing said first opening; and a second sealing member fit to the second valve element for airtightly sealing said second opening.