Abstract: A method and control system are provided for controlling apex flow in an array of parallel hydrocyclones, used for cleaning aqueous cellulose fiber suspensions, and arranged in a housing with a common inject chamber, base chamber and apex fraction chamber common to all hydrocyclones in the array, featuring the control of apex flow of cellulose fiber suspension by monitoring and maintaining apex flow at a selected value, increasing apex flow through the array whenever apex flow diminishes due to plugging of a hydrocyclone in the array, to aid in avoiding plugging of other hydrocyclones in the array.

Abstract: Process and apparatus are provided for cleaning chemical pulp by screening, in which the rejects from a first screening stage are rescreened in a second screening stage; the accepts from the second screening stage are separated in a hydrocyclone, and the clean fraction recycled to the first screening stage; the rejects from the second screening stage are beaten in a refiner and screened before or after the refiner; the suspension from the refiner is taken to the screen before the refiner, and the rejects from the screen after the refiner are recycled to the refiner.

Abstract: Method and apparatus in screening a fiber suspension in a pressure screen (10) with an inlet (1) for the fiber suspension and outlets (2, 3) for accept and reject, respectively, a conduit (12, 13) being respectively connected to said outlets, the reject conduit (13) opening to the atmosphere at its end facing away from the reject outlet and being at least partially at a higher level than both inlet (1) and reject outlet (3), the flow through said conduit (13) being measured, the difference between the measured value and a criterion value being determined, and the flow through the reject conduit (13) being changed in response to a function of the difference of the change of the flow through the accept conduit (12) by means of a valve (7) in said accept conduit (12).

Abstract: A process is provided for separation of gas mixtures into component fractions according to their molecular or atomic weight. The mixture is subjected to the centrifugal force applied in a cone-shaped vortex having a diameter of not over 5 mm. at a gas feed absolute pressure from about 5 to about 1000 mm. of mercury, and a pressure ratio within the range from about 1.5 to about 10. In the case where an inert gas is used in admixture with the gas mixture, the gas feed pressure can exceed 1000 mm. of mercury, and gas inlet and outlet pressures can range up to the liquefaction pressure of any gas in the mixture at the operating temperature. The higher molecular or atomic weight fractions are separated from an outer or peripheral portion of the vortex, and the lower molecular or atomic weight fractions are separated from an inner or core portion of the vortex.

Abstract: An apparatus is provided for separation of gas mixtures into component fractions according to their molecular or atomic weight, comprising a housing having a separator chamber therein that is circular in cross-section, has an apex end and a base end, and a diameter at the base end of at most 5 mm. A gas inlet at the base end is arranged for tangential flow of gas into the chamber, to establish a vortical gas flow from the base end towards the apex end. Gas outlets in the housing at the base end and the apex end are in axial alignment, the apex end outlet receiving peripheral vortical gas flow, and the base end outlet receiving core vortical gas flow, the lower molecular or atomic weight components being concentrated in the core flow, and the higher molecular or atomic weight components being concentrated in the peripheral flow, due to the centrifugal force applied in the vortex.