Diaphragm seals protect expensive measuring instruments from direct contact with potentially dangerous process media. Adding a diaphragm seal to a pressure gauge or sensor offers protection from corrosive media and mitigates the impact of both high- and low-temperature process media.
The negative impact of high temperatures on virtually all mechanical and electronic devices is well known, but not everyone is aware that exposure to very low temperatures can also damage sensitive equipment, particularly long-term exposure to extreme cold.
Diaphragm Seals Insulate Against High and Low Temperatures
Most measuring instruments can handle temperatures from below freezing to around 200°F without any additional protection, but at temperatures below zero or above 212°F, a diaphragm seal or other temperature mitigation device is recommended.
You can read more about the use of diaphragm seals in high temperature applications in this WIKA blog.
Materials behave differently at very low temperatures, and researchers have developed a number of manufacturing processes to exploit this fact. Recent research in the field of cryogenics has focused on how some materials become highly efficient superconductors at extremely low temperatures (below -238°F). This research has led to breakthroughs in scanning technology such as nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) commonly used in medicine today for diagnostic purposes.
WIKA is working hard to keep up with the demands of modern refrigeration technology. For example, the use of a diaphragm seal and a special temperature dissipation device and/or a long capillary line enables the measurement of process media as low as -202°F.
Diaphragm Seal Fill Fluids for Low Temperature Applications
Extremely low temperature applications require the use of a special fill fluid in the diaphragm seal assembly to avoid freeze ups. Standard halocarbons can be used at temperatures to approximately -60°F, special types of silicone oils or halocarbons are good at temperatures as low as -130°F, and methylcyclopentan won’t freeze up until temperatures are below -200°F.
Making sure that your pressure gauges and sensors provide accurate readings throughout their lifetimes means greater safety and less expensive downtime. Call or email the diaphragm seal experts at WIKA today to learn more about how diaphragm seals can protect your expensive instruments, no matter what temperature your processes require.
WIKA: We’re Not Just Pressure Gauges.