Schopper Riegler Tester
Schopper Riegler Freeness Tester
Freeness Tester & Slowness Tester
Schopper Riegler Apparatus
Professional Pulp Drainability Test
ISO 5267-1 BS 6035-1 TAPPI
CPPA C1 SCAN C21AS/NZS 1301.206s

Schopper Riegler Pupl Drainage Tester – Features:

The Schopper Riegler (SR) Test is a standardized method used to determine the drainability of pulp suspensions, which directly reflects the degree of refining of cellulose fibers. In this test, a defined volume of diluted pulp is poured into a chamber equipped with a precision screen. When the sealing cone is lifted, water drains through the screen while fibers form a temporary mat. The rate at which the filtrate passes through this mat is a sensitive indicator of fiber development, internal fibrillation, and fines content.

The test divides the filtrate into two paths: one portion flows freely into a graduated cylinder, while the remainder is diverted into the SR measuring chamber. The SR value corresponds to the volume retained in the measuring chamber, expressed in 'Schopper Riegler degrees'. A higher SR value indicates slower drainage and therefore a more highly refined pulp, while a lower SR value corresponds to faster drainage and less‑refined fibers. This makes the SR method particularly useful for monitoring refining efficiency and fiber treatment consistency in laboratory and mill environments.

Engineers rely on the SR test because it provides a fast, repeatable, and sensitive measure of fiber modification that correlates well with downstream papermaking behavior. Changes in SR values reflect variations in fiber flexibility, surface area, fines generation, and water retention — all critical parameters for sheet formation, strength development, and energy optimization in refining operations. The method is standardized under ISO 5267‑1 and TAPPI T227, ensuring global comparability and process control reliability.