Entwässerungswiderstand nach Schopper Riegler (SR)
Testing the dewatering capacity of aqueous pulp suspensions as a Schopper-Riegler value is carried out according to DIN EN ISO 5267-1.
The Schopper-Riegler value, also referred to as the freeness (SR), is a measure of the dewatering speed of a diluted pulp suspension. A defined volume is dewatered via a sieve in a separation chamber. The volume fraction of water in a measuring cylinder with Schopper-Riegler scale is read via the lateral discharge pipe.
The dewatering behaviour depends on the surface condition and the swelling state of the fibres. This key figure is used to assess the mechanical treatment, e.g. by milling.
Another method for testing is the dewatering behaviour as "Canadian Standard-freeness" CSF according to ISO 5267-2.