the gas flowing in a closed circuit

Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems > Cooling arrangements > characterised by the use of a forced flow of gas, e.g. air > the gas flowing in a closed circuit

Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems (lighting fixtures combined with outlets for air-treatment systems F24F13/078) > Cooling arrangements (air-treatment systems dissipating or using the heat of lighting fixtures F24F3/056) > characterised by the use of a forced flow of gas, e.g. air > the gas flowing in a closed circuit