Mixing device comprising a seal

A mixing device comprising a mixing container for receiving mixing material and a mixer cover,

• wherein a first seal is provided between the mixing container and the mixer cover, wherein there is a mixer stand and the mixing container is mounted rotatably about an axis of rotation with respect to the mixer stand and the mixing device has a drive with which the mixing container can be rotated about the axis of rotation,
• wherein the mixer cover is fixed to the mixer stand,
• wherein there is provided a second seal and the first and the second seal are so arranged that a first air space is formed between and contacts the first seal and the second seal,
• wherein the first seal seals off the first air space with respect to the interior of the mixing container while the second seal seals off the first air space with respect to the exterior of the mixing container and there is provided a first fluid passage having a first fluid passage opening which is arranged in the first air space, and
• wherein the first fluid passage opening is configured to feed fluid into the first air space to contact the first and second seal or to suck out fluid from the first air space in order to suck out mixing material constituents which may be in contact with the first seal or the second seal.