Abstract: A hot gas cleaning and heat transfer method associated with a cooking hood assembly to separate foreign matter and liquids from gas moving through the hood assembly and transferring heat from the gas to a cooling liquid. A heat conducting wall surrounding a tubular passage accommodating a plurality of helical elements divide and direct gas into separate helical gas streams. The cooling liquid surrounds the wall to lower the temperature of the wall. Foreign matter, gas vapors, and liquids are separated from the hot gas into an annular sheath adjacent the heat conducting wall. The foreign matter, gas vapors, and liquid particles suspended in the gas are combined by mechanisms of centrifugal force, adhesion, condensation, and impaction. The gas vapors are condensed into liquid droplets. The liquid droplets, liquids, and foreign matter merge into a liquid film on the inside of the wall. This liquid film is moved down the wall and collected in an annular collecting member located adjacent the exit end of the wall.

Abstract: A gas cleaning and heat transfer apparatus has a plurality of gas cleaning units that concurrently operate to separate foreign matter from the gas and reduces the temperature of the gas. Each cleaning unit has a heat conducting wall surrounding a tubular passage for carrying gas and foreign matter. A plurality of helical elements located in the passage are positioned in angular relationship relative to each other so that the gas moving through the passage is divided into separate helical gas streams. Heat from the gas in the passage is transferred through the wall to the fluid. The jacket around the cylindrical wall has a generally spiral rib in one embodiment which directs the flow of liquid in the chamber in a spiral path. The heating liquid is pumped to a location where the heat in the liquid is utilized. In another embodiment a spiral fin surrounds the heat conducting wall and a relatively airtight jacket surrounds the fin. Air cools the heat conducting wall as it circulates in the jacket.

Abstract: A gas cleaning and heat transfer apparatus associated with a cooking hood assembly to separate foreign matter from gas moving through the hood assembly and transferring heat from the gas to a liquid. The apparatus has a plurality of gas cleaning and heat transfer units. Each unit has a heat conducting wall surrounding a tubular passage accommodating a plurality of helical elements that divide and direct the gas into separate helical gas streams. A spiral ribbed jacket having a liquid accommodating a chamber surrounds the cylindrical wall and directs the flow of a liquid in the chamber in a spiral path. The foreign matter is separated from the gas as it moves in the spiral path through the passage by the combined mechanisms of centrifugal force, adhesion, condensation, and impaction. The liquid surrounding the wall lowers the temperature of the gas adjacent the inside of the wall causing condensation of vapors carried by the gas on the wall.

Abstract: A cooking unit having a hood equipped with air cleaning structures and blowers for moving air through the cleaning structures. The air cleaning structures include a pre-filter having spaced baffles for collecting air borne greases and particles. A primary fiber filter and secondary charcoal and oxidizer beds are located downstream of the pre-filter. A high efficiency filter is located downstream of the secondary cleaning beds. A damper behind the pre-filter closes in response to an increase in temperature of the air moving through the filters. A separate heating unit is used to reactivate the charcoal.

Abstract: A gas cleaning system having a gas filtering unit that is removably supported in a housing. The housing has a pair of rails containing upwardly open pockets. Hangers on the filtering unit have lips that fit into the pockets to support the unit on the rails in a selected position in the housing. A peripheral seal on the lower part of the housing engages the bottom of the filtering unit to insure that all the gas flows through the filtering unit. The gas filtering material is stored in chambers formed by spaced perforated walls in the unit. The tops of the chambers are closed with covers carrying the hangers.

Abstract: A hood assembly for use with cooking equipment having a plurality of units for separating foreign matter from air moving through the hood assembly. Each unit has a cylindrical tubular member having a passage for carrying the air and entrained foreign matter. A plurality of helical elements are located in the passage. The adjacent helical elements are located in 90.degree. relationship relative to each other so that the air moving through the passage is divided into separate helical paths which direct the air in spiral patterns whereby the foreign matter is separated from the air by the mechanisms of centrifugal force, adhesion and impaction. The foreign matter is collected and carried to a container. The cleaned air is recycled into the environment surrounding the hood assembly.