Apparatus for forming and dewatering a fibrous web

Abstract

Abstract APPARATUS FOR FORMING AND DEWATERING A FIBROUS WEB COMPRISES, ACCORDING TO THE EXEMPLARY EMBODIMENTS, A FORMING ROLL AND A SUCTION COUCH ROLL SPACED AT SUBSTANTIAL DISTANCE FROM EACH OTHER GENERALLY HORIZONTALLY AND A FIRST MOVABLE, ENDLESS, TENSIONED FORAMINOUS BELT TRAINED AROUND A PORTION OF THE FORMING ROLL AND CONDUCTED ALONG A STRAIGHT RUN TO AND AROUND THE SUCTION COUCH. A SECOND BELT IS LED AROUND THE FORMING ROLL AND DEFINES WITH THE FIRST BELT AN ARCUATE WEB-FORMING ZONE EXTENDING ALONG A PORTION OF THE FORMING ROLL. THE TWO BELTS ARE LED IN CONVERGENT DIRECTIONS TO THE FORMING ROLL TO DEFINE A TAPERED INLET ZONE WHERE A RIBBON-LIKE JET OF FIBER STOCK IS INTRODUCED. THE TWO BELTS RUN TANGENTIALLY FROM THE FORMING ROLL TOGETHER ALONG A PART OF THE STRAIGHT PATH FROM THE FORMING ROLL TO THE COUCH ROLL, AND THE SECOND BELT IS SEPARATED FROM THE WEB PART WAY ALONG THE STRAIGHT RUN BY LEADING IT OUT AROUND A CARRIER ROLL. ONE OR MORE PRES- SURE OR VACUUM BOXES ARE PROVIDED ALONG THE STRAIGHT RUN OF THE BELTS BETWEEN THE FORMING ROLL AND THE COUCH ROLL TO ESTABLISH A DIFFERENTIAL PRESSURE ACROSS THE WEB TO DEWATER IT. THE FIRST BELT, I.E., THE BELT WHICH RUNS FROM THE FORMING ROLL TO THE COUCH ROLL, IS ARRANGED SO THAT IT CARRIES THE WEB ON ITS UPPER SURFACE AFTER THE SECOND BELT IS SEPARATED. PRESS ROLLS MAY BE PROVIDED ALONG THE STRAIGHT RUN OR AT THE COUCH.

Inventors

• 👤 Lars Bengt Jordansson

Bibliographic Details