Freeness Tester (CSF)

Freeness Tester CSF – Canadian Standard Freeness Tester for Pulp

The Freeness Tester (CSF) measures the drainage rate of a diluted pulp suspension — a property known as pulp freeness or drainage. Freeness is inversely related to the degree of pulp refining: highly refined pulp drains slowly (low CSF value) while less-refined pulp drains quickly (high CSF value). It is a fundamental quality control measurement for all paper and board grades.

What is CSF (Canadian Standard Freeness)?

CSF is measured in millilitres (mL) of drainage water collected from a standardised pulp suspension under defined conditions. The scale runs from 0 mL (fully refined, very slow drainage) to 900 mL (unrefined, very fast drainage). Most printing and writing papers are produced from pulps in the 350–500 mL CSF range.

Freeness Tester Specifications

• Test standard: TAPPI T227, ISO 5267-2, IS 1060 Part 4
• Sample volume: 1,000 mL at 0.3% consistency
• Screen plate: 100-mesh (149 µm) stainless steel
• Bottom orifice: 3 mm diameter valve
• Graduated collection cylinder: 0–1000 mL with CSF scale
• Temperature: Test conducted at 20°C ± 0.5°C
• Material: Stainless steel and anodised aluminium

Applications

• Monitoring refiner settings and pulp quality in paper mills
• Incoming raw material quality control
• Comparison of recycled vs. virgin fibre properties
• Research and development of new paper grades

JS Civil Lab Solutions supplies the Freeness Tester with TAPPI-compliant screen plate and calibration verification kit. Contact us at +91 93596 24761 for pricing and lead times.