Abstract: A valve has a closing member that can be brought from a closed position into an open position by a rotational movement about an axis of rotation transverse to a through-flow direction. A shaft is connected to the closing member and comprises a shaft end. A valve housing has an adjusting device, which has an adjusting device housing and comprises a receptacle in which the shaft end can be received. In order to be able to fix the valve in a switching position, a shaft portion comprises a passage that can be made congruent with two housing-side openings. The passage and the openings can be penetrated by a securing body, and the connection between the shaft and the shaft portion is secured against release when the passage and the openings are congruent.