Dual Zone Wireless Pulp Washer

Abstract

A wireless dual zone pulp washer with rotating concentric filters for creating centrifugal force against feedstock in order to expel liquid contained in the feedstock before further processing of the stock. A secondary filter surrounds the primary filter to capture viable pulp fibers expelled from the feedstock by the dewatering process.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the priority benefit of U.S. Provisional Patent Application 60 / 563,066 filed Apr. 16, 2004.FIELD OF THE INVENTION [0002] The present invention is related to the washing and / or thickening of pulp and more particularly to a washer with a two stage dewatering zone without a wire belt. BACKGROUND OF THE INVENTION [0003] The pulp and paper making industry has for many years made regular use of apparatus for washing and / or thickening pulp and paper stock. One apparatus commonly used in the prior art practice, described in U.S. Pat. No. 5,382,327 by Seifert et al., is known as a double nip thickener (DNT) or simply a washer and is relatively closely comparable in structure and mode of operation with a cylinder type paper forming machine in that its main components are a pair of wire-covered cylinders and a vat in which the cylinders rotate. [0004] The DNT may be used as an extraction device, to thicken the stock, or may ...

AI Technical Summary

Problems solved by technology

Since the product of the machine is pulp, rather than a sheet on which wire marking may be undesirable, the wire may be of the pin seam type wherein the ends of the wire belt include overlapping loops which are releasably fastened together by a metal “pin” inserted through these loops.

In addition, a wire thickener or washer has limited rotational speed due to wire belt and other component wear concerns, thus the hydraulic capacity of the machine is directly related to the rotational speed.

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