Abstract: A delivery lance for the homogeneous mixing of water-soluble products comprises two coaxial hollow cylindrical members (1), (3) inserted one in the other, the first one (1) being provided with an axial chamber (13) for receiving a mass (66) of soluble product, and the second one (3) defining a surrounding annular chamber (4, 5) which communicates with said chamber (13) through transverse apertures (15) provided in said first member (1). The chamber (13) is provided with an end inlet mouth (10) for the water, which enters the annular chamber (4, 5) with turbulent motion, to then flow towards a discharge mouth (32) remote from the inlet mouth (10). To increase the water turbulence, a perforated jacket (20, 21) can be disposed about the first member (1) to divide the annular chamber into two concentric interspaces (4), (5).