Patent ID: RE39688

Claim:
A twin disk refiner comprising: a housing having portions defining a stock inlet and portions defining a stock outlet, wherein flow of stock from the stock inlet to the stock outlet defines a downstream direction from the inlet to the outlet and defining an upstream direction from the outlet to the inlet; a shaft which extends into the housing and which supports a rotor for rotation within the housing, and wherein a first rotating disk and a second rotating disk are mounted on the rotor so that the first rotating disk faces a direction opposite a direction faced by the second rotating disk; portions of the housing which define a first plate support structure through which the shaft extends; a first fixed refiner disk mounted to the first plate support structure; a second fixed refiner disk mounted to a second plate support structure; a refining chamber defined within the housing between, the first plate support structure and the second plate support structure, wherein the rotor is positioned within the refining chamber so that rotation of the rotor moves the first rotating disk and the second rotating disk about the shaft in refining relation to the first fixed refining disk and the second refining disk; and portions of the housing upstream of the refining chamber which define an upstream chamber in communication with the inlet, wherein the first plate support structure has an upstream face which is exposed to and substantially surrounded by the upstream chamber, such that fluid introduced into the housing at the inlet flows through the upstream chamber and then into the refining chamber, such that the first plate support structure is exposed to fluid pressure on its upstream face which counters the fluid pressure applied to the first fixed refiner disk within the refining chamber.