Active sealing device comprising: - a flexible sealing film having a first end and a second end; - a guide means having two mutually spaced guide surfaces (22, 25), which form a guide channel that has a channel inlet and a channel outlet; and - the sealing film enters the guide channel through the channel inlet and exits the guide channel through the channel outlet, the sealing film being shiftable in the guide channel; - a drive member arranged on the channel inlet side; - the first end of the sealing film is fastened to the drive member; - the second end of the sealing film is fastened to the guide means outside the guide channel and/or in the region of the channel outlet; - the drive member is movable between a retracted position and an extended position; - the guide channel is designed such that by transferring the drive member from the retracted position into the extended position, the sealing film is pushed through the guide channel towards the channel outlet, such that the sealing film forms a hose seal in the region of the channel outlet; and - the guide channel is designed such that by transferring the drive member from the extended position into the retracted position, the sealing film is pulled through the guide channel towards the channel inlet, characterised in that - the drive member comprises a rotatable driving shaft; in that - by rotating the drive member from the retracted position into the extended position, the sealing film is partially unrolled from the driving shaft; in that - by rotating the drive member from the extended position into the retracted position, the sealing film is rolled up on the driving shaft; and in that - the channel inlet or the guide channel is arranged tangentially below the drive member such that when the sealing film is unrolled from the drive member, the sealing film is moved or pushed through the channel inlet into the guide channel. - a flexible sealing film having a first end and a second end; - a guide means having two mutually spaced guide surfaces (22, 25), which form a guide channel that has a channel inlet and a channel outlet; and - the sealing film enters the guide channel through the channel inlet and exits the guide channel through the channel outlet, the sealing film being shiftable in the guide channel; - a drive member arranged on the channel inlet side; - the first end of the sealing film is fastened to the drive member; - the second end of the sealing film is fastened to the guide means outside the guide channel and/or in the region of the channel outlet; - the drive member is movable between a retracted position and an extended position; - the guide channel is designed such that by transferring the drive member from the retracted position into the extended position, the sealing film is pushed through the guide channel towards the channel outlet, such that the sealing film forms a hose seal in the region of the channel outlet; and - the guide channel is designed such that by transferring the drive member from the extended position into the retracted position, the sealing film is pulled through the guide channel towards the channel inlet, characterised in that - the drive member comprises a rotatable driving shaft; in that - by rotating the drive member from the retracted position into the extended position, the sealing film is partially unrolled from the driving shaft; in that - by rotating the drive member from the extended position into the retracted position, the sealing film is rolled up on the driving shaft; and in that - the channel inlet or the guide channel is arranged tangentially below the drive member such that when the sealing film is unrolled from the drive member, the sealing film is moved or pushed through the channel inlet into the guide channel.