Audibert Arnu Dilatometer Expansion Tube and Expansion Rod Assembly for Bituminous Coal Testing

Product Overview

This specialized dilatometer retort tube and expansion rod assembly serves as the core test chamber and displacement transmission system for evaluating the swelling, softening, and caking properties of bituminous coal. Precision-engineered to satisfy the rigorous mechanical and thermal requirements of international standard dilatometric testing, the equipment accommodates prepared coal pencils under exact physical constraints during controlled heating cycles. By functioning as the primary containment vessel, the system ensures that linear expansion and contraction measurements reflect genuine fuel behavior rather than mechanical artifacts or external interference.

Designed primarily for metallurgical coke manufacturing laboratories, coal washing and blending facilities, academic research institutes, and third-party inspection agencies, this hardware delivers the dimensional repeatability necessary to determine Audibert-Arnu dilation metrics. The assembly reliably withstands repetitive thermal cycling up to 600°C while subject to volatile gas evolution and continuous contact with expanding carbonaceous matter. By standardizing sample confinement, the components enable technicians and plant engineers to rank coking quality accurately, optimize blend formulations, and prevent structural oven damage.

Crafted from high-grade, oxidation-resistant stainless steel, the hardware guarantees structural integrity and dimensional consistency throughout demanding thermal regimes. The precision-machined bore minimizes frictional drag against the expanding coal mass, while the bottom threaded plug ensures absolute gas containment to preserve standardized sample chamber conditions. Laboratories can rely on this robust tooling to deliver predictable, non-reactive physical performance during repetitive industrial shifts and critical compliance audits.

Key Features

• Precision Micro-Honed Internal Bore: The 15 mm internal diameter of the retort tube is machined and honed to an ultra-low surface roughness, drastically reducing mechanical friction between the inner wall and the moving coal pencil or piston to ensure pure volumetric displacement data.
• High-Temperature Oxidation-Resistant Stainless Steel: Fabricated from a specialized austenitic alloy formulated to retain tensile strength and yield resistance at continuous testing temperatures reaching 600°C without flaking, blistering, or scale detachment.
• Leak-Proof Threaded Bottom Sealing Plug: The precision-threaded end plug provides an airtight, positive mechanical barrier at the base of the retort tube, eliminating the leakage of expanding tars and pyrolytic gases to protect heating furnace cavities.
• Precision Ground Expansion Transmission Rod: Designed with strict axial concentricity and exact geometric tolerances, the companion expansion piston rod transfers micro-scale swelling and contraction directly to measurement transducers without binding or flexing.
• Superior Resistance to Thermal Creep and Ovality: High mechanical yield strength ensures the barrel maintains perfect cross-sectional roundness and straightness over hundreds of thermal cycles, preventing sample jamming and false contraction readings.
• Standard-Compliant 350 mm Barrel Geometry: Built to strict dimensional standards with an approximate 350 mm tube length, allowing full immersion within standardized furnace heating zones for stable, uniform axial thermal gradients.
• Chemically Inert Surface Properties: The selected alloy composition resists hot chemical attack from sulfur, chlorine, and organic volatile compounds generated during coal pyrolysis, ensuring a clean release of post-test semi-coke residue.
• Modular and Easy-Clean Architecture: Featuring a fully detachable base plug and smooth internal channel, the apparatus simplifies routine residue extraction and solvent or mechanical cleaning between successive test batches.

Applications

Technical Specifications

Why Choose This Product

• Exceptional Dimensional Stability: Each assembly undergoes strict quality control to guarantee strict concentricity and precise bore tolerances, eliminating sample binding during critical coal plastic phases.
• Advanced Alloy Metallurgy: Selected specifically for demanding thermal cycling up to 600°C, the high-temperature stainless steel avoids wall scaling and chemical degradation from aggressive pyrolytic coal tars.
• Gas-Tight Reliability: The precision-engineered threaded sealing plug creates a secure mechanical seal, preventing the leakage of volatile emissions into heating blocks and preserving accurate sample pressure dynamics.
• Extended Operational Lifespan: With superior creep resistance and durable, oxidation-resistant walls, the equipment withstands continuous laboratory use without warping, lowering recurring consumable overheads.
• Seamless Compliance: Engineered in strict alignment with standardized Audibert-Arnu dilatometer dimensions, this hardware integrates effortlessly into legacy and modern testing platforms alike.

Connect with our technical sales engineers today to request a quote or discuss custom metallurgical laboratory hardware solutions tailored to your operational requirements.

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