Web handling process

Abstract

A process of transporting at least a portion of a web from a first structure to a second structure via an apparatus that includes at least two pulleys located at spaced locations from each other, an air-pervious endless belt positioned to run from the first structure to the second structure, an underpressure source arranged to produce an underpressure adjacent to the run of the endless belt, a nose shoe disposed beyond the second pulley and spaced from the second pulley, thereby defining an opening. The nose shoe has an inlet and air jet outlet positioned adjacent the second pulley. A guiding tray is arranged beyond the nose shoe having an upstream section positioned adjacent the nose shoe, and the upstream section includes an air slot, which extends cross-wise to a web travel direction. The process includes transferring the at least a portion of the web from the first structure onto the endless belt, holding the at least portion of the web onto the endless belt through the underpressure, directing air from the air jet outlet through the opening in a direction against a rotational direction of the second pulley, transferring the at least a portion of the web from the endless belt to the nose shoe, and directing an air curtain from the upstream section of guiding tray along a surface of the guiding tray, whereby the at least a portion of the web is guided over the guiding tray.

Description

[0001] The present application is a divisional application of U.S. Pat. Application No. 09 / 373,561 filed Aug. 13, 1999, the disclosure of which is expressly incorporated by reference herein in its entirety.[0002] 1. Field of Invention[0003] This invention relates to an apparatus for transporting a web of a flexible material between a first and a second position. In particular, and in a preferred embodiment, the invention provides an apparatus, known as a "vacuum conveyor", for transporting a web, preferably a lead strip of a paper web from the dryer of a paper-making machine to the first nip of a calendar of the machine or to a winding machine or between any other sections of a paper-making or paper-finishing (e.g. coating) machine.[0004] The present invention is intended as an improvement over the operation of the apparatuses described in U.S. Pat. Nos. 3,355,349 and 4,022,366. All features disclosed in these patents are incorporated into the present patent application by reference...

AI Technical Summary

Benefits of technology

[0013] A further improvement may be achieved by a second air slot arranged at the downstream end of the guiding tray, e.g. between the metal plate and an auxiliary plate arranged parallel to the metal plate, e.g., similar to German Utility Model G 91 09 313.9. The auxiliary plate may extend beyond the downstream end of the guiding tray and can be effective as a prolongation of the guiding tray.

Problems solved by technology

However, lightweight tissues still give problems.

Lightweight tissue has been found to fall over the end of the shoe out of control.

The improved apparatus works well in most circumstances but it has been found that as the velocity of the paper-making or paper-finishing machines is increased up to more than 2000 meters per minute, it becomes more and more difficult to property project the web or lead strip from the downstream end of the apparatus to the following structure or to the following section of the machine.

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