Abstract: An improved method and system for flue gas recirculation (FGR) from the ID Fan located downstream of a scrubber (or other Air Quality Control Equipment including cyclones, baghouses, etc., hereafter “AQC equipment”) back to the scrubber (or other AQC Equipment) inlet to maintain the minimum required flue gas throughput during low-load conditions, thereby eliminating the need for a separate booster fan. A flue gas recirculation duct is connected from downstream of the ID Fan to the inlet of the scrubber (or other AQC Equipment). A variable flow restrictor is placed in the duct downstream of the ID Fan for controlling pressure of the recirculated flue gas. The flow restrictor is controlled in accordance to a function of boiler load or flue gas flow to produce the required backpressure that enables the flue gas to flow through the recirculation duct back to the inlet of the scrubber (or other AQC Equipment) at low loads.

Abstract: A wind directional vent and skylight combination including: (a) a throat which may be in the form of a hood (60) rotatably mounted to a structure such as a building and in communication with a cavity to be exhausted such as a room of the building; (b) wind directional means associated with the hood (60), the wind directional means optionally being inherent in the shape and configuration of the hood (60), the wind directional means causing the hood (60) to rotate in response to changes in wind direction, wherein the hood (60) is made from material adapted to permit the passage of light therethrough.

Abstract: A roof ventilator comprises a duct 1 having a symmetrical hood 3 supported at its apex 4 by bearing 10. In the absence of wind, hood 3 is spaced from the upper end 2 of duct 1 with its depending skirt 6 surrounding upper end 2 However, wind from any direction causes the hood to tilt so that skirt 6 is lowered on the windward side thus increasing the ventilation rate and thus positioning hood 3 to deflect wind and wind-borne material from the ventilator opening.