| 摘要 |
<p>To control the flow of cleaning liquid through a liquid delivery pipe to a suction cleaning head, a valve unit (21) is releasably associated with an air flow regulator assembly forming part of the suction line (10). The air flow regulator assembly (11) regulates the flow of air into the suction line through a bleed hole (15) in the absence of the valve. When the valve unit is in place the bleed hole (15) is in communication with a pressure chamber within the valve unit, and a pivoted flap (29) is movable within the pressure chamber towards and away from the bleed opening (15). A piston (25) is coupled to the flat (29) and co-operates with a port (24) in the liquid supply line.</p> |
