METHOD AND APPARATUS FOR RESTORATION OF MISSING PARTS OF PAPER SHEETS Russian patent published in 1997 - IPC

FIELD: restoration of sheets of books, journals, may be used in book depositories, archives, museums. SUBSTANCE: method involves spreading sheets; covering sheets with composition containing fibrous mass and binder; forming founding; effectuating vacuum dehydration and contact drying. During dehydration process, vacuumizing is combined with supplying of air flow heated to 50-65 C, with air flow rate sucked through founding being maintained within the range of 30-50 mm/sec. Apparatus has sheet spreading units positioned in succession and embraced with endless netted conveying belt, founding forming device, dehydration unit with chamber positioned below netted belt and communicated with vacuum system, and drying unit with drying cylinders. Apparatus is further provided with airduct having heater. Airduct is mounted for vertical displacement in dehydration unit above netted endless belt in opposed relation to chamber communicated with vacuum system. Outlet openings of airduct and chamber, which adjoin endless netted belt, coincide in their size. It allows continuous high-quality seam at old and newly cast sheet portion boundary to be obtained. EFFECT: increased efficiency, simplified method, wider operational capabilities and improved quality of sheets. 3 cl, 1 dwg, 1 tbl