Valve slide with slide housing

In a valve slide including a slide housing, the slide defining a passage opening having an axis, a closing member which is slidable in its plane into a closed position for closing the passage opening, a sealing surface being provided on the housing in the region of the slide passage opening, a circumferentially closed sealing member formed in one piece arranged on the closing member, the sealing member resting against the sealing surface when the closing member is in the closed position, the sealing surface having imaginary straight generatrices extending parallel to the axis of the slide passage opening, the sealing member having two principal sections and lateral sections connecting the principal sections, the two principal sections of the sealing member being located in planes which are spaced apart from each other and extend perpendicularly to the axis of the passage opening, the closing member having a surface which carries the circumferentially closed sealing member and corresponds in its shape to the sealing surface of the housing, the improvement comprising the lateral sections of the circumferentially closed sealing member being U-shaped and having sides, the sides of the U-shaped lateral sections being located in a plane, the sealing surface having portions which are located one behind the other in axial direction of the slide passage opening, the sealing surface portions being contacted by the principal sections of the sealing member when the sealing member is in the closed position, the sealing surface portions having an area in which they have a common straight generatrix which extends parallel to the axis, laterally outwardly extending plane sealing surface portions being connected in the area to the sealing surface portions which are located one behind the other, the plane sealing surface portions being located in planes which extend parallel to each other and parallel to the axis of the slide passage opening.