AIR BARREL WHITE PAPER: This whitepaper discusses methods of measuring stress in storage tanks and compressed gas pressure vessels. Common techniques for installing strain sensors are presented, as well as an innovative strategy utilizing fiber optic devices. A demonstration of a pressurized air tank strain monitoring system is described, showing the ease of installation for such devices and the large improvement in resolution and scope compared to traditional foil strain gauges.

Large tanks hold everything from milk to propane to liquid nitrogen. These vessels must be maintained and monitored closely to ensure there isn't any chaos. The tanks cannot be over-pressurized and must be structurally sound, but how can we confidently determine the structural integrity of the tank? We can use real-time strain sensors to constantly observe the pressure in the tank. Traditional strain gauges are clunky and cumbersome to install. The future of strain measurement is the use of fiber optics because more sensors can be used with less bulk (when compared to traditional strain gauges), and the fibers can be attached easily to any surface using traditional installation methods.

Our air barrel demonstration simulates the real-world use of a pressure vessel. The barrel will burst at 15 PSI of relative pressure so a regulated air compressor will pump up to 4 PSI of air into the barrel. The air will then be released and the barrel's shape will return to normal. The process will repeat to simulate the average use cycle of a large tank.

There is a total of 20 feet of hair-like fiber glued to a plastic barrel to detect expansion. The 4DSP RTS150 will collect, in real time, high spatial resolution strain data from two fibers. The fibers have sensors embedded every half inch for optimal data collection. The fiber is epoxied to the barrel's circumference from bottom to top. The detailed results of the demo are readily available in the WHITE PAPER.

Not only is the fiber easier to install than traditional strain gauges, but it provides higher spatial resolution data, faster data collection, and improved long-term stability for any environment ranging from sub-arctic refrigerators to a sauna with a giant magnet. Real-time fiber optic instruments are the future of strain data collection and 4DSP is pioneering the technology.