A WIKA engineer noticed something disturbing during a recent instrument audit at a chemical plant: Hydrofluoric acid (HF) was corroding the lens of a pressure gauge.
“The plant was on the brink of an HF leak,” recalls Brandon Rudy, a senior instrumentation engineer for WIKA and a member of the company’s Full Audit Service Team (FAST), whose engineers provide instrument audits as a value-added service.
Used to produce chemicals that are required to make a variety of manufactured goods, HF is an incredibly corrosive and highly toxic material. A leak can easily lead to dangerous situation. Fortunately for the chemical plant, the issue was detected in the nick of time: The FAST engineer immediately alerted plant personnel, who addressed the problem before there was loss of containment.
In this particular incident, the diaphragm seal had failed, clearing a path for the acid to start eating its way to the surrounding work environment.
Diaphragm seals are standard for applications that involve highly corrosive materials such as HF. When made from the appropriate material, they protect the gauge from media to prevent failure and safety issues that can lead to slowdowns or shutdowns. But when they fail, there often aren’t any outward signs.
“Even the most robust diaphragm seal can wear down after continuous exposure to a harsh chemical,” said Raimund Weissner, WIKA Instrument’s technical director for diaphragm seals. “That’s why regular monitoring must always be performed.”
Diaphragm Monitoring System provides extra protection
To supplement regular inspections of critical diaphragm seal applications, WIKA has developed a patented double-diaphragm design, which provides an optical, electrical or audio warning to alert operators that a diaphragm seal needs to be exchanged.
In this design, a vacuum is created between the two diaphragms. This space is monitored by a measuring device — a pressure switch, pressure gauge or pressure transmitter. When this vacuum is compromised, the warning signals that corrective measures are required.
Double-diaphragm design and break monitoring are useful in chemical and pharmaceutical applications, but should never replace other inspection protocols. Such vigilance is especially necessary in today’s processing industry, where operations are nonstop. Diaphragm seal break monitoring is just another tool to help support a safer, more productive workplace.
If you have questions or would like to learn more about WIKA’s double-diaphragm design for break monitoring, please send an email to diaphragmseals@WIKA.com.