The present invention relates to liquid dispensing system for a rotatable work tool (2), comprising a control valve (13), an inlet and outlet liquid guiding device (11, 15). The control valve (13) comprises a housing (18) with a rotatable drum part (19) arranged to rotate. The housing (18) comprises inlet and outlet tubes (21, 22) arranged to be connected to the liquid guiding devices (11, 15). The tubes (21, 11) have corresponding inlet and outlet openings (23) facing the drum part (19). The drum part (19) comprises a first seal (25) and a third seal (27), the seals (25, 27) running around the drum part (19). The third seal (27) has an extension (34) running partially along the first seal (25), such that a first and second volume (28, 29) are formed. Each opening (23, 24) is connected to one of the volumes, or both. At least one volume (29) enables fluid connection between the openings (23, 24) that is variable by means of the third seal (27) moving over one or more of the openings (23). Each such opening has a first maximum extent (30) in a first extension (35) and a second maximum extent (31) in a second extension (36), orthogonal to the first extension (35), the first extent (30) exceeding the second extent (31).