Hermetic seal

The legendary Hermes Trismegistus supposedly invented the process of making a glass tube airtight using a secret seal.

Green buildings may include windows that combine triple-pane insulated glazing with argon or krypton gas to reduce thermal conductivity and increase efficiency.

Applications for hermetic sealing include semiconductor electronics, thermostats, optical devices, MEMS, and switches.

Electrical or electronic parts may be hermetic sealed to secure against water vapor and foreign bodies to maintain proper functioning and reliability.

Declaration of Independence, and U.S. Bill of Rights were hermetically sealed with helium gas in glass cases housed in the U.S. National Archives in Washington, D.C..

Epoxy-based seals can increase signal density within a feedthrough design compared to other technologies with minimal spacing requirements between electrical conductors.

This type of glass-to-metal hermetic seal is generally used for low-intensity applications such as in light bulb bases.

The sealing process is performed at roughly 1000 °C in an inert or reducing atmosphere to prevent discoloration of the parts.

Choosing between glass versus ceramic depends on the application, weight, thermal solution, and material requirements.

Glass taper joints can be sealed hermetically with PTFE sealing rings (high vacuum tight, air leakage rate 10−6 mBar × L/sec and below),[6] o-rings (optionally encapsulated o-rings), or PTFE sleeves,[7] sometimes used instead of grease that can dissolve into contamination.

For these reasons, it is advisable to apply a light ring of grease at the fat end of the taper and not its tip, to keep it from going inside the glassware.