Apparatus and method for connecting in a switchable manner

A system comprising:

• an apparatus having a face and formed with a plurality of material inlet ports, a flushing inlet port, and an outlet port, the material inlet ports and flushing inlet port opening on the face;
• respective supplies of at least two different liquid materials, the supplies each being connected to a respective one of the material inlet ports;
• a supply of flushing medium connected to the flushing inlet port;
• a rotor having an entry face directly engaging the face of the apparatus without interposition of a seal, formed with a passage, and shiftable between a plurality of positions in each of which a respective one of the inlet ports is connected to the outlet port;
• and
• control means for moving the rotor between the positions such that, after each time the rotor is in a position connecting one of the material inlet ports to the outlet port and material has passed through the passage, the rotor is moved into a position connecting the passage with the flushing inlet port for flushing out the passage.