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Bagasse Pulp Fibre Length, Refining and °SR
Fibre length and °SR describe different aspects of pulp. Schopper-Riegler drainability is not a direct measurement of fibre length, and there is no universal °SR target for every bagasse product or moulding machine.
Planning guidance, not a verified plant specification. Project-specific technical review with Govind Kumar is available by enquiry; this article does not claim his personal technical sign-off.
Measure fibre characteristics separately
Ask the laboratory how it measures fibre length and reports the distribution, fines and any weighting basis. An average without the measurement method can hide differences between furnishes. Record the pulp source, grade and sampling procedure so results can be compared.
Bagasse origin does not fix a single fibre-length value. Processing history and sample preparation matter. Obtain measurements for the actual supplied pulp; do not use a generic internet value as an acceptance limit for a purchase.
Understand what refining is intended to do
Refining is a fibre-treatment step used to develop properties for an intended application. It is distinct from merely dispersing pulp sheets or separating fibre bundles. Voith's fibre-treatment information distinguishes refining from deflaking and describes refining in relation to fibre surfaces and bonding potential.
The practical question is whether the treatment improves the required product while keeping forming and moisture removal manageable. Refiner design, plate pattern, operating conditions and furnish all influence the result. More treatment is not automatically better.
Use °SR as one controlled test result
The Schopper-Riegler method is a pulp drainability test. State the applicable method and edition, sample preparation, water conditions, consistency and test procedure in your laboratory plan. °SR is not interchangeable with another freeness scale through an assumed universal conversion.
A change in drainability can arise alongside changes in fines, fibre treatment or other stock properties. It does not prove that fibres have reached a specified length, nor does it independently predict the cycle time on a production mould.
Design a trial matrix rather than copying a target
| Record | Compare with |
|---|---|
| Furnish and preparation | Supplier batch and baseline pulp properties |
| Refining conditions | Treatment history and measured power basis |
| Drainability and fibre analysis | Repeatable laboratory methods |
| Formed samples | Mass, formation, strength and intended function |
| Process behaviour | Forming, dewatering, pressing and drying observations |
Agree a verified operating window
Use trials to propose a range, then confirm it on the selected machine and product. Document the furnish, additives, consistency and utility conditions under which the result was obtained. Repeat checks when the pulp source or product changes.
Expert verification required: fibre-analysis method, current test-standard edition, refining settings and any proposed °SR range. This guide supplies no universal numerical target, refiner setting or guaranteed performance specification.
Common questions
Can I calculate fibre length from °SR?
Not as a direct measurement. Fibre analysis and drainability testing answer different questions; evaluate both using documented methods.
Which °SR should I use for bagasse plates?
Set a trial-based window for your furnish, product and process. A single universal number would be misleading without that evidence.
Sources and further reading
External references provide technical or regulatory context. They do not endorse PulpGuru or verify a proposed plant. Confirm current editions and requirements for your project.
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