Air Sensor for Hydraulic Fluid

Hydraulic systems are vital to aircraft. They are responsible for functions ranging from highly sophisticated flight controls to brakes. The Air Force uses approximately 1.5 million gallons of hydraulic fluid per year, resulting in over $15 million in procurement and disposal costs. Hydraulic fluid is usually drained from the aircraft during routine maintenance and disposed of as hazardous waste. Recently the Air Force has started purifying hydraulic fluid for reintroduction to aircraft. These purification systems require an online sensor to measure the quality of hydraulic fluid in real-time. The rapid, on-site ability to measure hydraulic fluid quality is essential to avoid significant delays in servicing aircraft. No online sensor currently exists to measure air content of hydraulic fluid. Air causes problems such as hotspots, cavitation in pumps, poor heat transfer, loss of power, decreased viscosity, foaming, and decreased flash point. InterSpace proposes to develop a unique sensor that noninvasively measures the percent air in hydraulic fluid. InterSpace has successfully tested this prototype sensor online with a Pall purifier at WPAFB. The sensor measures air content in real-time and works with operating hydraulic systems over a wide range of temperatures, pressures, and fluid types.