press section the paper web w travels supported on felts 41 through a number of dewatering press nips 42 the press roll 43 includes a suction gland 44 across which the felt supported web w passes the louvered steam box 10 39 is urged adjacent the web to improve web moisture profile by application of steam to the web exactly as described above with respect to the paper machine forming section shown in fig1 3 fig8 shows apertured steam pipe distributor 45 discharging steam under choked flow conditions through steel wool packing 46 into plenum 47 as shown in fig9 louver control means 48 includes compartments 49 across the width of the web and the louver blades 50 the discharge compartment walls 51 may be contoured somewhat to better direct the steam into contact with the web the steam hood works best where the plenum is located above the zone of steam discharge to the sheet in this position the non turbulent substantially zero velocity steam tends to float and disperse throughout the plenum rather than flow into any particular compartment if the plenum were underdeath the compartments steam would rise and try to escape out the closest opening if the steam were introduced at one end of the box it would tend to flow out the first available opening the tendency of steam to rise and flow sideways rather than downwards distributes the steam evenly throughout the plenum without depending upon a substantial pressure differential the plenum must be large enough so that it always remains at an insignificant pressure i e 1 20 of an inch of water whether the louvers are open or closed the damper clearances between the damper blade and the compartment walls are enough so that even if all the dampers are.