Fume hood

Abstract

A fume hood used in either a laboratory or industrial setting, the fume hood includes a cabinet formed with a chamber having a generally flat work surface, an open face and a sash door assembly for reciprocally opening and closing the open face. The fume hood further includes an airfoil directing airflow through the open face and into the chamber. A baffle is disposed in the fume hood. The baffle has a plurality of rows of regularly laterally spaced apertures wherein the rows are regularly spaced apart along the length of the baffle. The fume hood further includes an exhaust outlet from the chamber.

Description

BACKGROUND OF THE INVENTION[0001]I. Field of the Invention[0002]The present invention relates to a fume hood apparatus, and more particularly to a fume hood apparatus with a baffle member that efficiently evacuates contaminated air from the fume hood.[0003]II. Discussion of the Prior Art[0004]Fume hoods are used in both laboratories and industrial settings where hazardous or noxious chemicals are generated and released. In fact, fume hoods limit exposure to hazardous solids, liquids and gases. Generally a fume hood is a ventilated enclosed workspace which captures, contains and then exhausts hazardous or noxious fumes, vapors or particulate matter generated inside the hood. Fume hoods are used so that dangerous fumes and particles generated inside the hood are drawn away from the user to prevent or at least minimize inhalation of the contaminants.[0005]The American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (“ASHRAE”) has developed industry recognized sta...

AI Technical Summary

Benefits of technology

"The present invention provides a fume hood with an airfoil that directs airflow into the chamber to sweep the work surface of contaminated air. A rear baffle is placed within the chamber to create a vertical fume passage with regularly spaced apertures that allow the contaminated air to be drawn into the passage. The fume hood also has an air exhaust outlet from the chamber. The technical effect of this invention is to provide an efficient and effective fume hood for use in various laboratory settings."

Problems solved by technology

Airfoils were first used in connection with fume hoods because where there is no structure or device for directing the inward flow of air into the chamber, vortexes would form in the fume hood's chamber, such that if air pressure was varied even slightly the vortex would be disrupted and hazardous fumes would escape through the face of the fume hood.

However, long slots in the baffle create pressure drop zones just below the opening, creating a roll of air that does not join the air stream efficiently.

The arrangement used in the Lin '827 patent makes for poor circulation of air in the center of the chamber while also creating pressure drop zones below each slot.

When the slots are staggered and located close together in each assembly row, the air being drawn from the fume hood does not have sufficient space to form proper airflow channels.

Furthermore, the close proximity of each slot to one another makes it difficult to make an adjustable flow system.

However, the baffle in the Gilkison '233 patent produces an unreliable and inconsistent flow of air behind it.

Because there is little separation between the apertures, and therefore little resistance in the air, the top rows of perforations pull an excessive amount of air while the lower layers are deprived of proper negative pressure to safely and correctly pull the necessary amount of air.

Furthermore, variable exhaust is nearly impossible to attain due to the numerous apertures in the perforated baffle.

Constantly circulating such air often consumes a great deal of energy.

Furthermore, prior art fume hoods do not efficiently evacuate contaminated air and they allow the contaminated air to escape from the front of the cabinet through the face.

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