In a recent blog post by StrainBlogTM, the ifs and buts of performing strain measurements in cryogenic environments are discussed and the question of whether or not one can actually strain gage in such environments is answered.

YES!!!! 

With the correct strain gages and application tools, strain measurements can be performed in cryogenic environments

Such environments include cryogenic rooms or chambers within the medical industry, cryogenic transfer pumps used to transfer liquefied nitrogen during LNG processes, Nuclear Magnetic Resonance Spectroscopy (NMR) to name a few.

StrainBlogTM explains each of the recommended tools (including the strain gages) and environment required to perform strain measurements within cryogenic environments.

StrainBlogTM recommends using the WK-Series strain gage because it is rated for a minimum temperature of -269 °C. Additionally, it is fully encapsulated combined with high endurance lead wires. The M-Bond AE-10 or M-Bond AE-15 are recommended to bond the gages and bondable terminals to the internal shells of the tanks. Signal wires can be attached using the 361A-20R solder  However, 361A-20R contains lead so 450-20R solder would be the choice if a lead-free alternative is required. StrainBlogTM explains that cable of silver-plated copper with Teflon insulation (330-FTE) should be used to signal wires back to the instrumentation so that the cable would pass from inside the tank through a sealed gland, and then out to instrumentation. It was also suggested applying the M-Bond AE-10 epoxy over the exposed area and then reinforcing it with a layer of FGC-1 woven fiberglass cloth saturated with M-Bond AE-10, over the base coat of epoxy. StrainBlogTM explains that the fibreglass cloth serves to stabilize the epoxy during thermal cycling thus preventing the separation of the coating or cracking at cold temperatures. Any excess epoxy can be removed using a body putty paddle embedding the cloth into the epoxy.

The environmental requirements include:

Environment: Liquid nitrogen, though there is also expected exposure to humidity and water condensation.

Temperature during measurements: cryogenic, -320 °F (-196 °C)

Tank material: steel

Mode of testing: static measurements

Term: short-term testing, long-term between tests

To find out more, follow the link to the StrainBlogTM

To view the Micro-Measurements® products, follow the link

For a further discussion contact our Melbourne office by email or phone: +61 3 9874 5777