Patent ID: 6354514
Filing Date: 2002-03-12
Classification: D21C,F28D,F28F

Abstract:
A method of heating or cooling a pulp and paper industry fiber suspension having a consistency of 5-20% using a plurality of heat exchange surfaces defining a single flow channel having an inner diameter of between 0.2-3 m, comprising:a) directing the suspension as a uniform, substantially plug, flow at a flow rate below 5 m/s into the single flow channel so that a first portion of the suspension contacts and gives up heat to, or takes heat from, the heat exchange surfaces; b) at a first throttling location, throttling the flow of the suspension by causing a more than 30% reduction in the flow channel cross-sectional area, where the cross-sectional area is contiguous; c) after b) widening the single flow channel so that the suspension is again directed as a uniform, substantially plug, flow at a flow rate below 5 m/s into the single flow channel so that a second portion of the suspension, different than the first portion, contacts and gives up heat to, or takes heat from, the heat exchange surfaces; and d) repeating b) at least once at least one subsequent throttling location downstream of the first location, including a second throttling location spaced about 0.1-2 m from the first location.