Koehler K33900 Actual Gum Tester

Overview

The Koehler K33900 Actual Gum Tester is a precision-engineered laboratory instrument designed to quantify the actual gum content in aviation turbine fuels, motor gasoline, and aviation gasoline in strict accordance with ASTM D381 and equivalent international standards (IP 131, ISO 6246, DIN 51784). Gum formation—nonvolatile residue resulting from oxidation and polymerization of fuel components during storage—directly impacts engine reliability, intake valve sealing, and combustion efficiency. The K33900 employs controlled evaporation under standardized thermal and gaseous flow conditions: air jet evaporation for gasoline-type fuels and superheated steam jet evaporation for aviation turbine fuels. Its core architecture centers on a machined aluminum heating block with six independent sample wells, each accommodating a 100 mL test beaker. Unlike conventional oil baths, the solid-state metal block ensures rapid thermal response, uniform heat distribution, and minimal thermal lag—critical for reproducible residue quantification across replicate runs.

Key Features

• Six-position heated aluminum block with integrated stainless-steel steam superheater—enabling precise delivery of dry, saturated steam at controlled temperatures up to 290 °C for ASTM D381 Method A (turbine fuels).
• Microprocessor-based PID temperature controller with dual LED display (simultaneous setpoint and actual bath temperature in °C or °F) and ±0.5 °C stability over the full operating range (up to 246 °C).
• Digital mass flow meter and calibrated pressure regulator assembly for accurate, traceable air or steam flow control—fully compliant with ASTM D381 flow rate specifications (e.g., 55 ± 5 mL/s for air, 550 ± 50 mL/min for steam).
• Over-temperature protection circuit automatically de-energizes heating elements if bath temperature exceeds user-defined limits—meeting IEC 61010-1 safety requirements for laboratory electrical equipment.
• Modular brass conical adapters and stainless-steel nozzles ensure leak-free, repeatable gas delivery to each test port; all fluidic components are field-replaceable without tools.
• Self-contained design with all electronics, power supplies, and control logic housed within the main chassis—no external controllers or auxiliary cabinets required.

Sample Compatibility & Compliance

The K33900 supports standardized gum testing for all major aviation and automotive fuel classes specified in ASTM D381: aviation turbine fuel (Jet A, Jet A-1, JP-5, JP-8), aviation gasoline (Avgas 100LL), and unleaded motor gasoline. It accommodates standard 100 mL low-form beakers per test position and permits simultaneous analysis of six samples under identical thermal and flow conditions—enhancing throughput while minimizing inter-run variability. The system fully satisfies regulatory and quality assurance requirements for fuel certification laboratories, including compliance with ISO/IEC 17025 method validation protocols. Its design incorporates provisions for audit-ready documentation: optional RS232 serial interface enables direct integration with LIMS or electronic lab notebooks for raw temperature, flow, and timing data capture—supporting 21 CFR Part 11-compliant electronic records when paired with validated software.

Software & Data Management

While the K33900 operates as a stand-alone instrument with intuitive front-panel controls, it offers scalable digital connectivity. The optional RS232 communication port supports bidirectional data exchange with host PCs running Koehler-provided acquisition software or third-party SCADA platforms. This interface logs time-stamped bath temperature, setpoint, airflow/steam flow rates, and elapsed evaporation time—enabling automated report generation aligned with ASTM reporting templates. Firmware supports user-defined ramp profiles (e.g., step-wise temperature increases) and configurable alarm thresholds. All operational parameters—including calibration offsets and flow meter zero points—are stored in non-volatile memory and protected by password access, ensuring data integrity across shifts and operators.

Applications

The K33900 is deployed in refinery quality control labs, military fuel certification facilities, aviation OEM support centers, and independent petroleum testing laboratories. Typical use cases include: batch release testing of jet fuel prior to aircraft refueling; stability assessment of reformulated gasoline blends during seasonal transitions; investigation of gum-related intake valve sticking in engine durability studies; and root-cause analysis of filter plugging incidents in ground support equipment. Its robust construction and adherence to ASTM procedural rigor make it suitable for GLP- and GMP-regulated environments where traceability, repeatability, and method fidelity are mandatory—not optional.

FAQ

What standards does the K33900 comply with?
ASTM D381 (Methods A and B), IP 131, ISO 6246, DIN 51784, FTM 791-3302, and NF M07004.
Can the K33900 test both gasoline and jet fuel on the same unit?
Yes—switching between air-jet (gasoline) and steam-jet (jet fuel) modes requires only reconfiguration of the gas supply line and selection of the appropriate flow calibration curve via the front panel.
Is the steam superheater field-serviceable?
Yes—the stainless-steel superheater chamber and associated thermocouple are accessible through a service panel; replacement parts and calibration procedures are documented in the OEM service manual.
Does the instrument support automated data export for QA reporting?
With the optional RS232 interface and Koehler acquisition software, temperature, flow, and timing data can be exported in CSV format for inclusion in ASTM-compliant test reports.
What safety certifications apply to the K33900?
It conforms to IEC 61010-1 for electrical safety and includes redundant thermal protection (PID-controlled regulation + independent over-temperature cut-off circuit). CE marking is provided for models rated 220–240 V.