Control of exhaust systems

Abstract

Exhaust capture and containment are enhanced by means of automatic or manual side skirts, a sensitive breach detector based on interference effects, a combination of vertical and horizontal edge jets, and/or corner jets that are directed to the center diagonally from corners. Associated control functions are described.

1 - 12 . (canceled) 
     
     
         13 . A fume hood, comprising:
 a hood portion connectable to an exhaust system and having a recess with a lower edge therearound, the hood portion being configured to cover a fume source;   a jet generator located at said recess lower edge and configured to generate first and second jets from an identical source of air, said first jet being relatively horizontal in direction and said second jet being relatively vertical in direction;   said first jet being directed toward said hood portion recess,   wherein said first jet is a planar jet and said second jet is a planar jet.   
     
     
         14 . A fume hood as in  claim 13 , wherein said at least one of said first and second jets are defined by a series of circular jets arranged along a line along said recess lower edge. 
     
     
         15 . A fume hood as in  claim 13 , wherein said first and second jets are defined by respective series of circular jets arranged along respective lines following said recess lower edge. 
     
     
         16 . A fume hood as in  claim 13 , wherein:
 said hood portion has corners;   said first jet is directed perpendicular to said recess lower edge between said corners and in a direction that is diagonal with respect to said recess lower edge between said corners, and thereby toward a middle of said hood portion, at said corners.   
     
     
         17 . A fume hood as in  claim 13 , wherein said first and second jets are defined in pairs proximal to each other. 
     
     
         18 . A fume hood as in  claim 13 , wherein said first and second jets emanate from a plenum. 
     
     
         19 . A fume hood as in  claim 13 , wherein the hood portion lower edge has corners at respective ends thereof, the corners being beveled or curved, and the first jets are directed perpendicular to said recess lower edge. 
     
     
         20 . A fume hood as in  claim 13 , further comprising a wall, wherein the recess lower edge is a straight edge located opposite the wall. 
     
     
         21 . A fume hood as in  claim 20 , further comprising side skirts on lateral sides of the hood portion. 
     
     
         22 . A fume hood as in  claim 13 , wherein said jet generator is further configured to generate a combination of said first and second jets at said recess lower edge on forward and lateral sections thereof such that the first and second jets surround the recess on at least three full sides. 
     
     
         23 . A fume hood as in  claim 13 , wherein said jet generator is further configured to generate a combination of said first and second jets at said recess lower edge on forward and lateral sections thereof such that the first jets on the forward section are directed perpendicular to the first jets on the lateral sections. 
     
     
         24 . A fume hood, comprising:
 a hood portion connectable to an exhaust system and having a recess, the recess having a lower edge, the hood portion being configured to cover a fume source,   the recess having an open end at the lower edge, a closed end opposite the open end, and an interior space;   an exhaust intake opening to the interior space on a first side of the recess, the exhaust intake being covered by a filter thereby forming a portion of the recess closed end; and   a jet generator vertically spaced from the closed end and located at said lower edge on a second side of the recess opposite the recess first side,   the jet generator being configured to generate a first jet vertically spaced from and underneath the closed end and being configured to generate a second jet downwardly and away from the recess such that the first jet is aimed in a relatively horizontal direction and the second jet is aimed in a relatively vertical direction;   the jet generator being further configured to receive air from a source and to form the first and second jets as respective planar jets using the air from said source;   said first jet being aimed toward said hood portion recess first side.   
     
     
         25 . A fume hood as in  claim 24 , wherein said jet generator includes sections extending along lateral sides of the lower edge and is further configured to generate a combination of said first and second jets at said lower edge on forward and lateral sections thereof such that the first jets on the forward and lateral sections are aimed in intersecting directions. 
     
     
         26 . A fume hood as in  claim 24 , wherein said filter is a cartridge filter having an inlet face arranged at an angle so as to partly face the recess open end and partly face the second side, and the jet generator is configured to direct the first jet toward the exhaust intake. 
     
     
         27 . A fume hood as in  claim 24 , wherein the jet generator is located on multiple sides of the recess so as to surround at least a portion of the recess. 
     
     
         28 . A fume hood as in  claim 24 , wherein the jet generator includes a plenum and at least one opening therein configured to release pressurized air so as to generate the first and second jets. 
     
     
         29 . A fume hood, comprising:
 a hood portion connectable to an exhaust system and having a recess, the recess having a lower edge therearound, the hood portion being configured to cover a fume source;   a jet generator located at said lower edge and configured to generate a first jet aimed in a relatively horizontal direction and a second jet aimed in a relatively vertical direction, the first jet being aimed toward said hood portion recess; and   an exhaust intake that opens to the recess and is arranged at a non-zero angle with respect to a plane containing said lower edge such that the exhaust intake faces an interior of the recess;   wherein the recess has a closed end and an open end at the lower edge, the recess interior including an end wall portion adjacent to the closed end,   the jet generator is vertically spaced from the closed end and includes a plenum having at least one opening configured to release air from the plenum so as to form the first and second jets as respective planar free jets, and   the jet generator at least one opening is configured to form the first jet directed along a plane that is spaced from the end wall portion of the recess interior and to form the second jet directed away from the recess.   
     
     
         30 . A fume hood as in  claim 29 , wherein the at least one plenum extends along a forward side and at least one lateral side of the lower edge to define a concave perimeter so as to generate said first and second planar jets along said forward side and said at least one lateral side. 
     
     
         31 . A fume hood as in  claim 29 , wherein the exhaust intake includes a filter, the filter bounding the interior of the recess.