The present invention relates to a portable device for spraying a liquid at low pressure, said device comprising a spray arm (220), and characterized in that the spray arm comprises at least one flat fan spray nozzle (230). Preferably, the liquid is a cleaning composition for treatment of carpets and other large fabric coverings, more preferably, a composition comprising surfactants. Also preferably, the portable device is electrically driven, and/or the spray arm is extendible and/or detachable from the device's main unit.