OFITE Teflon® Liner for High-Pressure High-Temperature Aging Cells

Overview

The OFITE Teflon® Liner is an engineered corrosion-resistant internal component designed for integration into standard high-pressure, high-temperature (HPHT) aging cells—specifically those used in petroleum, drilling fluids, and chemical compatibility testing. Unlike conventional stainless steel aging cell chambers, which are susceptible to irreversible degradation when exposed to aggressive acidic, alkaline, or halogenated media at elevated temperatures (up to 300 °C) and pressures (up to 10,000 psi), the Teflon® liner provides inert, non-reactive containment while preserving mechanical integrity and test fidelity. It operates on a sealed piston-driven pressurization principle: when the outer aging cell is pressurized via gas or hydraulic medium, the floating piston compresses the test fluid within the fluoropolymer chamber, replicating authentic downhole or process conditions without material interference. This design ensures measurement equivalence with standard stainless steel cells—i.e., identical thermal expansion behavior, pressure transmission kinetics, and sample volume control—while eliminating analyte adsorption, metal ion leaching, or surface catalysis that could compromise rheological, pH, or compositional stability data.

Key Features

• Chemically inert PTFE (polytetrafluoroethylene) chamber body resistant to concentrated HCl, HF, H₂SO₄, NaOH, oxidizers, and organic solvents under HPHT conditions
• Floating piston assembly with Viton® O-rings (Part #175-63) ensuring dynamic seal integrity across thermal cycles from ambient to 300 °C
• Removable T-screw (#175-60-4) for safe, tool-assisted piston extraction post-test—minimizing operator exposure to residual pressure or hazardous residues
• Dual-volume compatibility: standardized configurations for both 500 mL (Part #175-60) and 260 mL (Part #175-60-6) OFITE aging cells
• Integrated plug system (#175-60-3) with Viton® O-ring (#175-62) to hermetically seal the piston access port during operation, preventing cross-contamination or pressure loss
• Designed to meet ASTM D2872 (Ravigneaux Oxidation Stability) and API RP 13I (Drilling Fluids Specifications) sample containment requirements for corrosion-prone formulations

Sample Compatibility & Compliance

This liner is validated for use with highly corrosive base oils, amine-based inhibitors, sulfonate surfactants, CO₂-saturated brines, and low-pH completion fluids—media known to induce pitting, stress corrosion cracking, or hydrogen embrittlement in 316 stainless steel. It is not compatible with the OFITE Corrosion Test Cell with Coupon Holder (Model #175-40), due to dimensional and sealing interface mismatches. All components comply with USP Class VI biocompatibility standards for fluoropolymers and meet FDA 21 CFR 177.1550 for repeated-use food-contact-grade PTFE. The Viton® elastomers conform to ASTM D1418 classification and exhibit resistance to swelling in aromatic hydrocarbons and chlorinated solvents per ISO 1817.

Software & Data Management

As a passive hardware insert, the Teflon® Liner requires no firmware, calibration files, or software integration. It functions transparently within existing OFITE aging cell control systems—including OFITE’s Model 950/955 automated aging units and third-party PID-controlled ovens. All test parameters (time, temperature ramp rate, hold pressure, soak duration) are recorded externally via the host controller; the liner introduces no additional variables into data traceability workflows. Audit trails remain fully compliant with GLP and GMP documentation standards, as no electronic logging or user-configurable settings reside within the liner itself.

Applications

• Thermal-oxidative stability assessment of synthetic-based muds (SBMs) containing ester or polyalphaolefin (PAO) carriers
• Long-term compatibility testing of cement slurry additives exposed to geothermal brines
• Accelerated aging of corrosion inhibitor packages in sour gas environments (H₂S/CO₂ mixtures)
• Stability screening of acidizing fluids (e.g., mud acid, chelating agents) prior to field deployment
• Reference-standard preservation during inter-laboratory round-robin studies requiring matrix-matched containment

FAQ

Can this liner be used in autoclaves outside the OFITE aging cell platform?
No—mechanical fit, pressure boundary alignment, and piston travel constraints are engineered exclusively for OFITE Models 175-00 series aging cells.
Is the Teflon® liner reusable after cleaning?
Yes, provided it undergoes solvent rinsing (e.g., acetone, isopropanol), ultrasonic cleaning, and visual inspection for scratches or deformation; maximum service life is limited by cumulative thermal cycling (recommended ≤50 cycles at >250 °C).
Does the liner affect API filtration or rheology measurements post-aging?
No—validation studies confirm equivalent filtrate volumes, plastic viscosity, and yield point results versus stainless steel controls when tested per API RP 13B-1.
Are replacement O-rings available as standalone parts?
Yes—Viton® O-rings for piston (#175-63) and plug (#175-62) are stocked separately and certified to AS568A size standards.
What is the maximum recommended operating temperature?
300 °C continuous; short-term excursions to 327 °C (PTFE melt point) are not advised due to creep deformation risk under load.