Valve device

A valve device to be arranged in a pipe through which a fluid flows, the valve device comprising:

• a rotation shaft;
• a valve body configured to be rotationally displaceable about the rotation shaft between a closed position in which a blocking degree of the pipe by the valve body is relatively large, and an open position in which the blocking degree is relatively small;
• and
• a biasing portion biasing the valve body so as to cause the valve body to approach the closed position,
• wherein the valve body comprises an upstream wall arranged in a position upstream of the rotation shaft in a flow direction of the fluid when the valve body is in the closed position,
• wherein the valve body comprises a rotation end, which is an end distal from the rotation shaft and is configured to move downstream in the flow direction of the fluid in response to a displacement of the valve body from the closed position to the open position, and the rotation end is shaped to project upstream when the valve body is in the closed position,
• wherein the rotation end of the valve body is located in the upstream wall,
• wherein a portion in the upstream wall located closer to an opposite end to the rotation end comprises a surface facing upstream, the surface being configured to be located downstream of the rotation end when the valve body is in the closed position, and
• wherein the rotation shaft is arranged in a position between the rotation end and the opposite end to the rotation end in a radial direction of the pipe, the position of the rotation shaft being spaced from a central axis of the pipe in the radial direction.