Bernoulli Effect Smoke Draft Vent Assembly

Abstract

A crown-like structure sits atop a chimney or smokestack as a specially formed chimney cap wherein passing air is required to take a somewhat convoluted path, providing a Bernoulli effect to improve smoke emission draft. Like at least two of its predecessors, the crown has two roof-like canopies, one within the other, each having a series of curved, bent strips separated to permit the wind-flow to pass through. As a departure from the past, the number of sets of strips, or leaves, within each canopy is raised to optimize performance, the preferred number thereof being three.

1 . A Bernoulli effect smoke draft vent assembly comprising
 a first vent canopy;   a second vent canopy; and   a collar;   each canopy comprising three or more venting leaves disposed to cross one another proximate their centers;   the first vent canopy disposed to overlie the second in separation therefrom;   the venting leaves of the first canopy disposed in angular offset array from those of the second canopy;   the collar axially disposed below the vent canopies and comprising diameter sufficient for axial connection upon a smokestack;   the venting leaves further disposed to curve downward and further configured at their ends with embracing flanges, wherein the embracing flanges are attached to the collar.   
   
   
       2 . The Bernoulli effect smoke draft vent assembly according to  claim 1  wherein by reason of the relative attachment sites of the venting leaves upon the assembly's collar, those of the first canopy are disposed in angular offset array from those of the second canopy. 
   
   
       3 . The Bernoulli effect smoke draft vent assembly according to  claim 1  wherein the central angle between each pair of adjoining venting leaves equals that between each other pair thereof and the angular offset array of the first canopy's venting leaves with respect to those of the second is regular such that each first canopy venting leaf bisects the central angle between a pair of adjoining venting leaves of the second canopy. 
   
   
       4 . The Bernoulli effect smoke draft vent assembly according to  claim 1  wherein the width of all venting strips is equal throughout their respective lengths. 
   
   
       5 . The Bernoulli effect smoke draft vent assembly according to  claim 1  wherein the venting leaves of each canopy are connected to one another by interleaf attachment means. 
   
   
       6 . The Bernoulli effect smoke draft vent assembly according to  claim 1  wherein the collar is cylindrically configured. 
   
   
       7 . The Bernoulli effect smoke draft vent assembly according to  claim 5  wherein the interleaf attachment means comprises welds.