Fluid Densitometer DESCRIPTION AMETEK’s new fluid densitometer builds on the legacy of a military sensor which has been in service for over 20 years. The new sensor features several key improvements to make the product more accurate and less expensive. The densitometer uses a torsional mode natural frequency to determine density in real time, providing an accurate and reliable indication of fuel density over the temperature ranges typically encountered in aircraft fuel tank applications. It is designed to operate in all aircraft fuels encountered worldwide. One end of a spring is driven torsionally to resonance using an oscillating electrical signal by a piezoelectric crystal, the other end of the spring is allowed to freely vibrate at its natural frequency. This end is “coupled” with the fluid media and natural frequency changes in response to the fluid density are measured on a second drive piezoelectric crystal. The primary output is an AC voltage having a frequency that varies with density. Density is calculated from the output frequency via the equation: p = a + b/frequency2, where a and b are constants determined during calibration. The standard method of acquiring the frequency in a microprocessor based system is with a timer/counter chip having a two-second gate time insuring high resolution. SAFETY The intrinsically safe design is certified for operation in fuel tanks. - Capacitance is negligible compared to wire capacitance - Meets FAR part 25 requirements - Max current limited by 2K ohm series resistors on all wires to sensor FEATURES S High accuracy over extremes in both fuel, temperature, and viscosity S Output can be provided in flight as well as at ground check ✓ Provides stable air check output for diagnostics after installation S Suitable for use in flowing fuel applications such as ground or inflight refueling systems S Torsional vibration mode less sensitive to structural input error S Insensitive to pressure changes S Piezoelectric crystals used rather than fine solenoid coil windings AMETEK* AEROSPACE

Fluid Densitometer SPECIFICATIONS ELECTRICAL CHARACTERISTICS Voltage: +7 VAC Amperage: 5 milliamp ENVIRONMENTAL CHARACTERISTICS Temperature: -67O to 185OF (-55O to 85O C) Accuracy: +0.4% at-67O to 140OF (-55° to 60O C) Viscosity: up to 30 centistokes Operating Pressure: 0.1 to 1.4 bar Repeatability: +0.04% Long Term Drift: +0.03% per year PHYSICAL CHARACTERISTICS Sensing Weight: 4 oz. (.11 kg) OTHER CHARACTERISTICS Output signal: 4-20 mA or proportional DC voltage Integrated digital interface available for fully compensated system intergration CONSTRUCTIONS - NiSpanC alloy torsional spring -...