The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 30, 1991
Filed:
Jun. 08, 1989
Victor E Hansen, Jacksonville, FL (US);
David T Smith, Monson, MA (US);
Douglas R McPherson, East Longmeadow, MA (US);
Richard E Pitt, Carleton Place, CA;
JWI Ltd., Kanata, CA;
Abstract
A method and apparatus are disclosed whereby the rate of drainage of the stock on a Fourdrinier paper making machine can be controlled for the full length of an open surface forming section. A continuous sealed drainage box is used from adjacent the head box slice to the end of the forming section, within which the air pressure can be controlled. In the area adjacent the head box slice drainage is hindered by the use of a positive (above ambient atmospheric) pressure, while further along the forming section the pressure is decreased to a negative value (below ambient atmospheric). Improved paper formation and first pass retention are obtained.