Mixing installation with a dosing device

A mixing installation for mixing a first agent to a liquid, wherein the mixing installation comprises a liquid supply conduit, a mixture discharge conduit, a dosing assembly between the liquid supply conduit and the mixture discharge conduit, a first agent container, and a first agent supply conduit between the first agent container and the dosing assembly,

• wherein the dosing assembly comprises a venturi arrangement between the liquid supply conduit and the mixture discharge conduit, and a first dosing device between the first agent supply conduit and the venturi arrangement,
• wherein the first dosing device comprises a first main body with a first agent passage that is in fluid communication with the first agent supply conduit and the venturi arrangement, and a first dosing mandrel having a first dosing pin that extends in the first agent passage,
• wherein the first dosing mandrel is reciprocally slidable in its axial direction with respect to the first main body over a first release stroke by pulling between a dosing position in which the first dosing pin extends inside the first agent passage to define a first ring shaped dosing channel around the first dosing pin with a constant first radial flow height around the circumference of the first dosing pin, and a retracted release position in which the first dosing pin is fully retracted from the first agent passage and the first ring shaped dosing channel is cancelled.