: The Enlightenment during the 17th â 18th century produced philosophers and scientists who focused on human reason and rational thought to solve problems and provide ethnical systems for living. Enlightenment thinkers believed in natural over supernatural forces or laws.
A purge valve is the part of the vehicle Evaporative Emission Control (EVAP). system. The EVAP system prevents fuel vapors in the fuel tank from escaping into the atmosphere.
Shut down valve. A shut down valve (also referred to as SDV or Emergency Shutdown Valve, ESV, ESD, or ESDV) is an actuated valve designed to stop the flow of a hazardous fluid upon the detection of a dangerous event. This provides protection against possible harm to people, equipment or the environment.