The tray has an infusion field of infusion tab valves adjacent the inlet to dissipate the momentum of the liquid flowing across said infusion field. Each valve includes a vertically upstanding wall of a height to obstruct the flow of liquid and the valves are disposed in a staggered array. An adjacent bubbling area has openings for the passage of an ascending flow of vapor into contact with the liquid/vapor mixture flowing across the area. Each infusion tab valve may also have a push valve incorporated therein.