Double seat valve and sealing of double seat valve

The method of sealing and the double seat valve double-seat valve. Having a valve disk with two (T, T ') cooperating seat (6) of the double seat valve (V), wherein two valve discs may be linearly adjusted with respect to one another and may be linear with respect to the valve seat adjusted, a seat valve function and the slide valve function, two valve disks each of which comprises an annular seal member (R, R ') has an elastic sealing ring (17) in an annular groove (N), the two a sealing ring (17) is made with the same shape and size, each sealing ring (17) along a support ring (16, 16 ') positioned in an annular groove (N), and two sealing rings (17) with respect to the valve disk (T, T ') in the adjusting direction (X) based on the respective sealing function are arranged in different turning positions.