Heat transfer surface for air preheater

Abstract

A heat transfer element includes a plurality of adjacent heat transfer plates. Each of the heat transfer plates has oppositely disposed first and second heat transfer surfaces and a plurality of laterally spaced notches. A first heat transfer plate of each pair of adjacent heat transfer plates has at least one tall notch and the second heat transfer plate of each pair of plates has at least one short notch, where the notch height of the tall notch is greater than the notch height of the short notch. Each of the tall notches of a heat transfer plate are received in a short notch of an adjacent heat transfer plate to thereby define flow channels therebetween.

What is claimed is:  
     
         1 . A heat transfer element comprising a plurality of adjacent heat transfer plates, each heat transfer plate having oppositely disposed first and second heat transfer surfaces and defining a plurality of laterally spaced notches, each of said notches comprising adjacent, mutually parallel, first and second lobes, each first lobe extending transversely from the first heat transfer surface to a crest and each second lobe extending transversely from the second heat transfer surface to a crest, the crests of the first and second lobes defining a notch height, adjacent heat transfer plates defining a pair of plates, a first heat transfer plate of each pair of plates having at least one tall notch and a second heat transfer plate of each pair of plates having at least one short notch, the notch height of the tall notch being greater than the notch height of the short notch, each of said tall notches of a heat transfer plate being received in a short notch of an adjacent heat transfer plate to thereby define flow channels therebetween.  
     
     
         2 . The heat transfer element of  claim 1  wherein said notches of each heat transfer plate comprise at least one tall notch and at least one short notch.  
     
     
         3 . The heat transfer element of  claim 1  wherein the notches of each of the heat transfer plates comprises a plurality of tall notches and a plurality short notches.  
     
     
         4 . The heat transfer element of  claim 1  wherein the notches of each first heat transfer plate of each pair of plates comprises a plurality of tall notches and the notches of each second heat transfer plate of each pair of plates comprises a plurality of short notches.  
     
     
         5 . The heat transfer element of  claim 1  wherein the notches of each heat transfer plate are substantially equidistantly laterally spaced apart.  
     
     
         6 . The heat transfer element of  claim 1  wherein each tall notch of each heat transfer plate has substantially the same notch height and each short notch of each heat transfer plate has substantially the same notch height.  
     
     
         7 . The heat transfer element of  claim 1  wherein each lobe has a lateral width, the widths of the first and second lobes of each short notch being greater than the widths of the first and second lobes of each tall notch.  
     
     
         8 . The heat transfer element of  claim 1  wherein the notches of each heat transfer plate define at least one intermediate surface having a plurality of protuberances extending transversely from at least one of the first and second heat transfer surfaces.  
     
     
         9 . A heat transfer element comprising a plurality of adjacent heat transfer plates, each heat transfer plate having oppositely disposed first and second heat transfer surfaces and defining a plurality of laterally spaced notches, each of said notches comprising adjacent, mutually parallel, first and second lobes, each first lobe extending transversely from the first heat transfer surface to a crest and each second lobe extending transversely from the second heat transfer surface to a crest, the crests of the first and second lobes defining a notch height, said notches of each heat transfer plate comprising a plurality of alternating tall notches and short notches, each of the tall notches having a substantially uniform notch height Ht and each of the short notches having a substantially uniform notch height Hs, Ht being greater than Hs, wherein for each pair of adjacent heat transfer plates, the second lobes of the tall notches of a first heat transfer plate of the pair are received in the first lobes of the short notches of a second heat transfer plate of the pair and the second lobes of the tall notches of the second heat transfer plate are received in the first lobes of the short notches of the first heat transfer plate to thereby define flow channels therebetween.  
     
     
         10 . The heat transfer element of  claim 9  wherein the notches of each heat transfer plate are substantially equidistantly laterally spaced apart, adjacent notches defining intermediate surfaces therebetween.  
     
     
         11 . The heat transfer element of  claim 10  wherein at least one of the intermediate surfaces of at least one of the heat transfer plates has a plurality of protuberances extending transversely from of the heat transfer surfaces.  
     
     
         12 . The heat transfer element of  claim 9  wherein in the flow channels, the second heat transfer surface of the first heat transfer plate is at a distance D from the first heat transfer surface of the second heat transfer plate, wherein D=Ht−Hs  
     
     
         13 . The heat transfer element of  claim 9  wherein each lobe has a lateral width, the widths of the lobes of each short notch being greater than the widths of the lobes of each tall notch.  
     
     
         14 . A heat transfer element for a rotary regenerative preheater comprising a plurality of adjacent heat transfer plates, each heat transfer plate defining a plurality of alternating, laterally spaced, tall and short notches, each of said notches comprising adjacent, mutually parallel, lobes extending transversely from opposite sides of said heat transfer plate, the tall notches having a substantially uniform height Ht and width Wt and the short notches having a substantially uniform height Hs and Ws, wherein Ht>Hs and Ws>Wt and wherein for each pair of adjacent heat transfer plates, lobes of the tall notches of each heat transfer plate are received in complementary lobes of the short notches of the other heat transfer plate to thereby define flow channels therebetween.  
     
     
         15 . A heat transfer element comprising a plurality of adjacent heat transfer plates, each heat transfer plate having oppositely disposed first and second heat transfer surfaces and defining a plurality of laterally spaced notches, each of said notches comprising adjacent, mutually parallel, first and second lobes, each first lobe extending transversely from the first heat transfer surface to a crest and each second lobe extending transversely from the second heat transfer surface to a crest, the crests of the first and second lobes defining a notch height, adjacent heat transfer plates defining a pair of plates, a first heat transfer plate of each pair of plates having a plurality of tall notches and a second heat transfer plate of each pair of plates having a plurality of short notches, each of the tall notches having a substantially uniform notch height Ht and each of the short notches having a substantially uniform notch height Hs, Ht being greater than Hs, wherein for each pair of plates, the second lobes of the tall notches of the first heat transfer plate are received in the first lobes of the short notches of the second heat transfer plate to thereby define flow channels therebetween.