Abstract: Non-return valve, in which, between the non-return valve assembly and the end of the valve body, which can be connected to a tap, emptying ports are provided and a shut-off diaphragm is supported, which, when the tap is closed, frees the run between the inside of the tap and the emptying ports and, when the tap is open, separates the inside of the tap from the emptying ports.

Abstract: An improved valve with ball-shaped stopper, comprising a valve housing in which the stopper forms a seal with two faces developing in parallel planes opposite each other and in which the ball-shaped stopper, the stopper handle and the control rod connecting them are formed in a single rigid piece. The stopper component is provided, on the stopper and on the part of the control rod adjacent to it, with a coating of a sealant which forms the seal toward the outside of the valve preventing fluid from leaking, and also forms the seal within the valve which regulates fluid flow.

Abstract: A non-return valve for supply cocks, comprising an integral cup-shaped valve body (8) accommodating a substantially rigid washer (14) forming a seal with respect to the supply cock (2) and having flow apertures (16), as well as a flexible membrane (15) located underneath and self-positioning, during closure, against the said substantially rigid washer (14) so as to close the said flow apertures (16) of the same (14) and move away from the said flow apertures (16) under the pressure of the water supplied. The substantially rigid washer (14) and the flexible membrane (15) may advantageously be joined together so as to form a composite washer (28). The valve (1) proposed has a small number of components and can be very easily assembled. The substantially rigid washer (14), or the composite washer (28), has an external thread (14a)so that the said washer (14; 28) can be screwed into the thread (8b) of the cup-shaped portion (8a) of the valve body (8).