Hermetically Sealed Device 2 : A device which prevents a hazardous or corrosive gas or vapor from coming in physical contact with an arcing or high temperature component. (RP 14F)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}