Cryogenic FOSS (CryoFOSS)

Cryogenic FOSS (CryoFOSS)

Armstrong innovators have developed a highly accurate method for measuring liquid levels using optical fibers. Unlike gauges that rely on discrete measurements to give broad approximations of liquid levels, Armstrong's novel method provides measurements at 0.25-inch intervals within a tank. The system uses FBG sensors located along a single fiber optic cable. These sensors actively discern between the liquid and gas states along a continuous fiber to pinpoint the liquid level. This significant leap forward in precision and accuracy in liquid level sensing offers important benefits to many industries. Designed to monitor a rocket's cryogenic fuel levels, the technology can be used in many medical and industrial applications.

Work to date: The technology has been demonstrated in multiple environments using conventional validation techniques. First, water level measurements have been conducted to demonstrate operation within a benign environment. Second, liquid level measurements were conducted in liquid nitrogen using a 6-foot dewar. Measurements also were conducted within a liquid hydrogen environment using a 4-foot dewar. The technology performed well in all three cases, demonstrating the ability to measure liquid to 0.25 inches.

Looking ahead: The team continues to push the technology's fields of application, with future tests to determine boundary layers between different fluids, such as oil and water.

Benefits

 Precise: Requires just one fiber optic strand and one metallic wire

 Safe: Is not susceptible to electromagnetic interference

 Robust: Can be used in corrosive or toxic liquids

Applications

 Aerospace launch vehicles and satellites  Chemical and refinery plants

 Industrial tanks

 Fiber Optic Sensing

Armstrong's portfolio of Fiber Optic Sensing System (FOSS) technologies offers unparalleled options for high-resolution sensing in applications that require a unique combination of high-powered processing and lightweight, flexible, and robust sensors. The system measures real-time strain, which can be used to determine two-dimensional and three-dimensional shape, temperature, liquid level, pressure, and loads, alone or in combination. Initially developed to monitor aircraft structures in flight, the system's capabilities open up myriad new applications for fiber optics-not just in aerospace but also for civil structures, transportation, oil and gas, medical, and many more industries.

The Armstrong approach employs fiber Bragg grating (FBG) sensors, optical frequency domain reflectometry (OFDR) sensing, and ultra-efficient algo-rithms (100 samples/second). Engineers are continually seeking new ways of looking at information and determining what is important. Armstrong's FOSS technologies focus on critical research needs. Whether it is used to determine shape, stress, temperature, pressure, strength, operational load, or liquid level, this technology offers ultra-fast, reliable measurements.