The valve has a ported valving element which removes from, and seats upon, a ported valve seat, to open and close the valve to fluid flow through a ported stop plate, and the valving element, in relation to ports in the stop plate, has relieved steps formed therein to create rolling vortices in the through-flowing fluid. Additionally, the valve, in a first embodiment thereof, has two ported buffer plates, however, the latter, vis-a-vis the stop plate ports, have no steps; rather the ports therein are of the same dimension as the ports in the stop plate with which they align or register.