Flush control apparatus

Apparatus for flushing a WC bowl or the like, comprising a water tank (1), an inlet valve (12), a discharge valve (15) and an actuating mechanism, the actuating mechanism comprising firstly a chamber (5) communicating with the water distribution system over an inlet pipe (14), a substantially vertical shaft (6) passing through the chamber bottom, a piston part (4) being connected inside this chamber, and secondly a part connected to the shaft (6) for generating a vertical movement of the shaft and the associated piston part, a counter-part (7) which is connected to the shaft (6) and is located at a location corresponding to the counter-part (8) of the discharge valve (15), and a device (11) for identifying the amount of water in the water tank and controlling the inlet valve (12), the amount of water used for flushing the bowl being controlled by means of an electrically driven inlet valve (12), which allows water to enter the chamber (5) through the inlet pipe (14) from the water distribution system, the water raising the piston part (4) and the shaft (6) in the chamber, the discharge valve (15) opening with the aid of the counter-parts (7, 8) and staying open until the inlet valve (12) is closed at the end of a period determined by the control unit (13) and the piston part (4) is pressed down under the force of gravity, after which the inlet valve (12) reopens, the water tank (1) refills and the control unit closes the inlet valve (12), characterised in that the part connected to the shaft (6) for generating the vertical movement of the shaft and the associated piston part (4) is a control mechanism (2) operating under the dynamic pressure of supply water.