Device for mixing at least two components, comprising a first container and a second container, each provided with a. at least one opening, connected by a duct and provided with a device for alternately varying the available volume of the first container and the second container, so as to transfer the contents of one of said first container or second container into the other first container or second container through the openings and said duct; b. at least one inlet opening for the first container and at least one inlet opening (X') for the second container, allowing the inlet of the at least two components; said mixing device not comprising an additional outlet opening, one of the inlet openings (X, X') allowing both the inlet of at least one component and the outlet of the obtained mixture of the at least two components, said mixing device being characterized in that it comprises at least a first main valve and a second main valve and at least one auxiliary valve, said valves (56, 56', 57) sliding in ducts provided in the mixing device; said first valve having two bores, one of the bores allowing access for cleaning water, and the other bore allowing access for a hollow needle, either to penetrate a component, or to let cleaning water out through the hollow needle, thereby cleaning it; said second valve having two bores, one of the bores allowing access to the component, and the other bore allowing access to a nozzle for supplying the product thus obtained by mixing; said auxiliary valve being provided with at least two bores, and being suitable for being translated by a system of racks which are actuated by a motor, and being capable of controlling the flow between said first container and second container. a. at least one opening, connected by a duct and provided with a device for alternately varying the available volume of the first container and the second container, so as to transfer the contents of one of said first container or second container into the other first container or second container through the openings and said duct; b. at least one inlet opening for the first container and at least one inlet opening (X') for the second container, allowing the inlet of the at least two components; said mixing device not comprising an additional outlet opening, one of the inlet openings (X, X') allowing both the inlet of at least one component and the outlet of the obtained mixture of the at least two components, said mixing device being characterized in that it comprises at least a first main valve and a second main valve and at least one auxiliary valve, said valves (56, 56', 57) sliding in ducts provided in the mixing device; said first valve having two bores, one of the bores allowing access for cleaning water, and the other bore allowing access for a hollow needle, either to penetrate a component, or to let cleaning water out through the hollow needle, thereby cleaning it; said second valve having two bores, one of the bores allowing access to the component, and the other bore allowing access to a nozzle for supplying the product thus obtained by mixing; said auxiliary valve being provided with at least two bores, and being suitable for being translated by a system of racks which are actuated by a motor, and being capable of controlling the flow between said first container and second container. said mixing device not comprising an additional outlet opening, one of the inlet openings (X, X') allowing both the inlet of at least one component and the outlet of the obtained mixture of the at least two components, said mixing device being characterized in that it comprises at least a first main valve and a second main valve and at least one auxiliary valve, said valves (56, 56', 57) sliding in ducts provided in the mixing device; said first valve having two bores, one of the bores allowing access for cleaning water, and the other bore allowing access for a hollow needle, either to penetrate a component, or to let cleaning water out through the hollow needle, thereby cleaning it; said second valve having two bores, one of the bores allowing access to the component, and the other bore allowing access to a nozzle for supplying the product thus obtained by mixing; said auxiliary valve being provided with at least two bores, and being suitable for being translated by a system of racks which are actuated by a motor, and being capable of controlling the flow between said first container and second container.