Abstract: The valve comprises a slider-valving member having two lateral valving elements (22, 22A, 22B) positioned on one and the other side of the transverse central plane, they being subjected to the direct action of thrust means (15) and movable axially between a first operative position defining said normal configuration of the slider-valving member (20, 20A, 20B), and a second operative position in which a further different communication condition between the channels is determined; spring means (23, 35, 45) are also provided, arranged to normally maintain the two lateral valving elements (22, 22A, 22B) in said first operative position.