Abstract: Butterfly valve comprising a valve housing and a flap and two soft sealing rings retained by undercut grooves in the valve housing and from said grooves radially inwardly projecting sealing lips for engagement with the sealing surface of the flap. By means of the two soft sealing rings which are separated by a flexible intermediate ring (18) of metal, the radial inner edge thereof is formed with two opposite directed sealing lips, a complete fluid sealing in both pressure directions is obtained. In the event of destruction of the soft sealing rings caused by eventual fire in the valve, the pressure of the fluid will result in deformation or flexing of the intermediate ring, so that the one or the other of the sealing lips is pressed against the sealing surface of the flap and, thereby obtaining a fire proof seal in both directions.