Product Overview

The KR‑411A Cobb water‑absorption tester applies the classic Cobb‑method principle to quantify surface water‑absorbing performance of paper and paper‑board materials. Under defined contact‑seal conditions, a fixed volume of water contacts a 100 cm² specimen surface for a set duration. Operators calculate the Cobb‑value (g/m²) from weight difference before and after water exposure, which reflects sizing effectiveness and surface‑water‑repellent properties of paper‑based substrates.

This bench‑top unit is engineered in strict accordance with GB/T 1540‑2002 specifications. Note that this instrument targets surface water‑absorption evaluation only and is not intended for assessing writing performance of paper products. Widely deployed across pulp‑paper mills, printing‑packaging enterprises, material‑R&D departments and accredited third‑party testing labs for routine incoming QC and finished‑paper quality grading. It works perfectly together with KR‑411B circular sample cutter and analytical balance to build a complete Cobb‑test workflow.

Core Product Competitive Advantages

1. Standard‑Calibrated Precision Metal Cylinder Assembly High‑precision machined stainless‑steel test cylinder delivers 100 ± 0.2 cm² internal cross‑section area with inner diameter of 112.8 ± 0.2 mm and cylinder height of 50 mm. Smooth polished annular contact surface guarantees leak‑tight sealing against specimen sheets and prevents liquid leakage that would distort final Cobb‑value readings.
2. Standard‑Weight Blotting‑Roller Mechanism Equipped with heavy‑duty smooth metal roller of 200 ± 0.5 mm length and 10 ± 0.5 kg total mass. Manual crank‑driven roller achieves consistent blotting pressure to squeeze surplus surface water evenly from specimens, eliminating human‑pressure variation during water‑removal step and securing good test repeatability for batch‑sample work.
3. Stable Manual‑Clamping Sealing‑Structure Adjustable screw‑type clamping knob enables uniform pressure onto cylinder‑gasket assembly. It achieves reliable sealing on diverse paper‑board surfaces. No electric power is required; the whole manual system can be set‑up anywhere on lab work‑benches.
4. Corrosion‑Resistant Integrated Stainless‑Steel Base‑Platform Large‑area anti‑rust metal base resists water‑splashing and chemical‑corrosion in daily lab‑environment. Component layout is optimized for easy access during specimen‑loading, water‑pouring and post‑test cleaning work.
5. Full‑Set Matching‑Lab‑Solution Compatibility Seamlessly compatible with KR‑411B 100 cm² circular sample cutter and high‑precision analytical balance. Users can assemble a complete sample‑cutting‑weighing‑absorption‑testing workstation to fulfil full‑procedure Cobb‑test requirements for paper‑board quality‑control.

Complete Technical Parameter Table

表格

Compliance Standard: GB/T 1540‑2002 Calculation Formula: C = (G₂‑G₁) × 100; C = Cobb‑value(g/m²), G₁=pre‑absorption specimen mass, G₂=post‑absorption specimen mass

Standard Complete Test Operating Workflow

1. Pre‑Test Preparation Place tester on level lab bench. Inspect cylinder sealing‑gasket for wear or damage. Prepare conditioned circular specimens cut by KR‑411B sampler, qualified blotting‑paper, timer, graduated water container and analytical balance. Weigh and record dry‑specimen mass value G₁.
2. Specimen Sealing & Water Injection Lay flat the pre‑weighed specimen beneath test cylinder. Tighten clamping knob to form leak‑proof seal. Pour 100 ± 5 ml test water into cylinder and start timing according to specified test duration for material grade.
3. Water‑Discharge & Blotting‑Processing Upon reaching preset soak‑time, drain residual water rapidly. Place qualified blotting‑paper onto wet specimen surface, operate hand crank to pass standard‑weight metal roller back‑and‑forth once for surplus‑water blotting treatment.
4. Specimen Re‑Weighing & Cobb‑Value Calculation Take‑out treated test‑piece immediately, perform second weighing to obtain G₂. Compute Cobb water‑absorption index by formula C = (G₂‑G₁) × 100. Complete parallel multi‑specimen testing and record average result for formal QC‑report.
5. Post‑Test Tidying Release clamping mechanism. Wipe water residues from cylinder, sealing‑gasket and base‑plate. Keep all metal components dry. Check gasket ageing status periodically and replace worn sealing‑parts when needed.

Wide Industrial Application Scenarios

Pulp‑Paper Manufacturing Plants

Surface water‑absorbency inspection for sized printing‑paper, coated‑paper, liner‑board and packaging base‑paper; evaluate sizing‑agent effect for production‑process adjustment.

Printing & Packaging‑Material Enterprises

Raw‑material incoming‑quality‑audit for carton‑board and label‑paper; assess anti‑water‑penetration performance for finished‑packaging products.

Paper‑Material R&D Departments

Performance‑comparison for different sizing‑formula paper‑grades, support new‑product development of water‑resistant packaging‑paper.

University Paper‑Science Laboratories

Teaching‑experiment hardware for paper‑packaging‑majors to study surface‑absorption characteristics of fibre‑based sheet‑materials.

Third‑Party Accredited‑Testing‑Organizations

Conduct GB/T 1540‑2002‑compliant Cobb‑absorption assessment and issue formal inspection‑documents for product‑certification audits.

Standard Factory‑Full‑Delivery Kit

1. KR‑411A Cobb‑method water‑absorption‑tester main‑unit (cylinder assembly, blotting roller, manual‑crank clamping‑mechanism, stainless‑steel base‑plate)
2. Standard sealing‑gasket spare set
3. Multilingual printed‑operation‑manual complying with GB/T 1540‑2002
4. Factory‑issued performance‑inspection‑certificate

Optional matching accessories: KR‑411B circular sample cutter, high‑precision analytical balance (sold separately).

Global Distributor & After‑Sales‑Support

We provide remote‑one‑on‑one operational guidance covering clamping‑sealing setup, blotting‑roller operation and routine gasket‑replacement maintenance. Spare‑parts stock includes sealing‑gaskets and wearing components. Bulk‑order customers can combine‑purchase together with sample‑cutting equipment. Regional‑exclusive‑agent privileges contain priority‑production‑scheduling, OEM private‑branding‑services and complete‑set high‑definition product‑marketing‑image‑resources.

Product‑Banner‑Marketing‑Slogan

KR‑411A Cobb‑Method Water‑Absorption Tester | GB/T1540‑Compliant Instrument For Paper‑Board Surface‑Water‑Absorbency‑Measurement

Core‑Feature‑Labels‑For‑Product‑Images

100cm² Standard‑Test‑Cylinder | Precision‑Leak‑Proof‑Seal | 10kg Standard Blotting‑Roller | Manual‑Crank Blotting Operation | Corrosion‑Resistant Stainless‑Steel Base | No‑Power Manual Operation | Compatible With KR‑411B Sampler | GB/T1540‑2002‑Compliant

Safety‑Operation‑Reminder

Avoid water splashing onto mechanical‑clamping components. Replace aged sealing‑gasket in time to prevent liquid‑leakage. Keep metal roller and cylinder clean and dry after finishing each‑batch testing.