Abstract: The unit of the invention comprises a motor-driven high pressure pump (11) having a delivery side (13) and a suction side (14), and a delivery gun (15) connected to the pump delivery side (13) by a delivery conduit (16) having a flow on-off valve. The valve unit comprises a by-pass valve (25, 33) arranged to close or alternatively, when in the open state, to enable direct flow passage between the delivery side (13) and the suction side (14), and having a control means (31, 32) sensitive to the liquid pressure in the delivery conduit (16); said control means comprises two valving elements (31, 32) which are normally joined together to form one piece in contact with the liquid of the delivery conduit (16), but which separate when the pressure in the delivery conduit (16) exceeds the normal delivery value (P1) following flow interruption by the delivery gun (15), to hence provide direct passage for the liquid from the delivery conduit (16) to the suction side (14).

Abstract: A tool (1) for a hydro cleaner machine adapted for the washing of surfaces by means of high speed water jets, comprising: a conveyor conduit (5) for high pressure water; a container tank (7) for a detergent, having an mouth for filling, and an mouth (71) for the discharge; and a distributor device (8) which, associated with said discharge mouth (71) of said container tank (7) is adapted to distribute the detergent on the surfaces to be washed.

Abstract: The unit of the invention comprises a motor-driven high pressure pump (11) having a delivery side (13) and a suction side (14), and a delivery gun (15) connected to the pump delivery side (13) by a delivery conduit (16) having a flow on-off valve. The valve unit comprises a by-pass valve (25, 33) arranged to close or alternatively, when in the open state, to enable direct flow passage between the delivery side (13) and the suction side (14), and having a control means (31, 32) sensitive to the liquid pressure in the delivery conduit (16); said control means comprises two valving elements (31, 32) which are normally joined together to form one piece in contact with the liquid of the delivery conduit (16), but which separate when the pressure in the delivery conduit (16) exceeds the normal delivery value (P1) following flow interruption by the delivery gun (15), to hence provide direct passage for the liquid from the delivery conduit (16) to the suction side (14).