Patent attributes
A plenum fan comprising a fan wheel disposed within a box-like enclosure includes a secondary inlet cone, a primary inlet cone, and a flexible duct. The two inlet cones convey air to the mouth of the fan wheel. A frame supports the fan wheel and the primary inlet cone such that the frame, the fan wheel and the primary inlet cone comprise a fan assembly. If the fan assembly shifts due to fan thrust or vibration, the fan assembly moves as a unit. The flexible duct connects the primary inlet cone to an inlet of the enclosure while isolating the fan assembly's vibration from the enclosure. The secondary inlet cone extends from the inlet of the enclosure, protrudes into or toward the primary inlet cone and provides a smooth airflow path over the abrupt shape of the flexible duct.
