: 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.
The relief valve (RV) is a type of valve used to control or limit the pressure in a system or vessel which can build up for a process upset, instrument or equipment failure, or fire. Pressure relief valve (PRV) or Pressure Release valve (PRV) or pressure safety valve (PSV): The difference is that PSVs have a manual lever to activate the valve in case of emergency.