Means for and method of improving drainage on fourdrinier machines

Claim 1

THE METHOD OF REMOVING DRAINAGE FROM A WEB FORMED ON AN ENDLESS FOURDRINIER WIRE COMPRISING THE STEPS OF (A) SUBJECTING THE WEB TO AN ABSOLUTE PRESSURE SUBSTANTIALLY BELOW ATMOSPHERIC PRESSURE BY, FIRSTLY, PASSING THE WEB OVER THE OUTGOING NIP OF A CONVEXLY CURVED SURFACE TO CREATE BY ACTION OF HYDRODYMANIC FORCES A SUCTION UNDER THE WEB AT SAID OUTGOING NIP, AND, SECONDLY, SUPPLEMENTING SUCH SUCTION BY IMMEDIATELY APPLYING A VACUUM TO THE WEB FROM A VACUUM CHAMBER UNDER THE WEB ADJACENT TO THE SAID OUTGOING NIP OF THE CONVEXLY CURVED SURFACE, AND (B) THEN SUBJECTING THE WEB TO A CONTROLLED SUBSTANTIALLY HIGHER ABSOLUTE PRESSURE TO PERMIT SOME RELAXATION TO THE WEB BY, FIRSTLY, PASSING THE WEB OVER A CHAMBER HAVING THEREIN A HIGHER ABSOLUTE PRESSURE THAN THAT IN THE FIRST MENTIONED VACUUM CHAMBER, AND, SECONDLY, SUPPLEMENTING SUCH HIGHER ABSOLUTE PRESSURE BY PASSING THE WEB OVER THE INCOMING NIP OF ANOTHER CONVEXLY CURVED SURFACE ADJACENT TO SAID SECOND MENTIONED CHAMBER TO CREATE BY ACTION OF HYDRODYNAMIC FORCES A POSITIVE PRESSURE UNDER SAID INCOMING NIP.