Method for emptying a device for providing a liquid additive

A method for operating a device for providing a liquid additive, the method comprising the following steps:

• providing a liquid additive feeding path including at least one first portion having a peristaltic pump able to be damaged by deposits precipitated from the liquid additive and including at least one second portion having a component susceptible to freezing;
• a) feeding liquid additive along the feeding path of the device;
• b) stopping the feeding of liquid additive;
• and
• c) partially draining the feeding path by maintaining liquid additive in the at least one first portion while draining the at least one second portion;
• and
• carrying out the partial draining of the feeding path in step c) by first completely draining the feeding path and subsequently partially filling the feeding path with liquid additive again to place liquid additive in the at least one first portion.

A device for providing a liquid additive, the device comprising:

• a feeding path for feeding the liquid additive along said feeding path, said feeding path having at least one first portion and at least one second portion;
• a peristaltic pump disposed in said at least one first portion and being able to be damaged by deposits precipitated from the liquid additive;
• at least one component susceptible to freezing being disposed in said at least one second portion disposed downstream in a dispensing direction of said feeding path to a dispensing port;
• at least one sensor element at a point of said feeding path between said peristaltic pump and said at least one component susceptible to freezing;
• and
• a controller being programmed to:
• a) feed liquid additive along said feeding path;
• b) stop said feeding of liquid additive;
• and
• c) partially drain said feeding path by maintaining liquid additive in said at least one first portion while draining said at least one second portion;
• monitoring the partial draining of the feeding path in step c) by using said at least one sensor element;
• detecting if there is liquid additive at said point by using said at least one sensor element;
• and
• stopping the draining as soon as there is no longer any liquid additive at said point.