ISO 5267-1:1999

Overview

ISO 5267-1:1999 - "Pulps - Determination of drainability - Part 1: Schopper‑Riegler method" specifies a laboratory test for quantifying the drainability of pulp suspensions using the Schopper‑Riegler (SR) method. The standard defines the SR number scale (0–100), the test principle, required apparatus (including the Schopper‑Riegler funnel and SR measuring cylinder), sample preparation, procedure, result expression and reporting. The SR number is an index related to fibre surface condition, swelling and the extent of mechanical treatment.

Key topics and technical requirements

• Test principle: Drainage of a known volume of dilute pulp suspension through a wire screen into a funnel; collected discharge in a cylinder gives a direct SR reading.
• SR scale: 1 000 ml discharge = SR 0; zero discharge = SR 100. Typical reliable results: 10–90 SR.
• Sample concentration & temperature:
  • Prepare stock near 0.22% mass fraction then dilute to 0.2%–0.002% as required.
  • Standard test temperature: 20.0 °C ± 0.5 °C (alternative 25 °C ± 5 °C if documented).
• Apparatus: Schopper‑Riegler drainage chamber with phosphor‑bronze wire screen, sealing cone, funnel and SR measuring cylinder (graduated so 1 SR = 10 ml). Annex A gives detailed dimensions and components.
• Procedure: Fill with 1 000 ml sample, raise the sealing cone after 5 s, read SR when side orifice stops dripping.
• Reproducibility: Perform two determinations; repeat if duplicates differ by more than 4%.
• Maintenance and calibration: Annex B covers leveling, screen gasket fit, cleaning, side/bottom orifice checking and cone raise rate (specified nominally in the standard), plus a water drain-time check using 1 000 ml at 20 °C (149 s ± 1 s).
• Limitations: Not recommended for very short-fibred, heavily beaten hardwood pulps where fibres pass through the screen. SR results may not directly correlate with paper‑machine drainage.

Applications

• Routine laboratory evaluation of pulp drainability / freeness.
• Quality control during pulping, refining and mechanical treatment processes.
• Comparative testing of fibre treatment effects (beating/refining, chemical treatments).
• Equipment verification and method standardization in pulp and paper testing labs.

Who uses this standard

• Pulp and paper laboratories, QC/QA technicians, process engineers, pulp mill chemists, laboratory equipment manufacturers and standards bodies involved in pulp testing.

Related standards

• ISO 5267-2 - Part 2: “Canadian Standard” freeness method (alternative freeness test).
• ISO 14487 - Standard water for physical testing (specified water quality for the SR test).
• ISO 4119 - Determination of stock concentration (used during sample prep).

Keywords: ISO 5267-1:1999, Schopper‑Riegler method, SR number, drainability, pulp testing, freeness, standard water, pulp and paper.