Grate Bar and Grate for a Step-Grate Stocker with Directed Air Combustion

Abstract

A grate bar and a grate for stepped-grate furnace stoker with directed-air combustion. Its principle application is in the field of furnaces for waste conversion units. The bar includes a flat part, whose top surface receives the incinerated elements, and that extends into two rear and front ends each forming a return that acts as a support point for the bar. It also includes a longitudinal projection under the flat part, extending at least partially between the rear and front ends. At least one wing is positioned under the flat part, on a first side of the longitudinal projection. In a characteristic manner, this wing has at least one lateral hollow-out which, together with the lateral hollow-out of a wing of a neighbouring bar, forms a passage for channeling air up to the front end of the bar.

1 . A bar for a grate in the firebox of an incineration furnace that includes:
 a flat part whose top surface is intended to receive the elements to be incinerated, with the said flat part extending in a rear end and a front end each forming a return that acts as a support point for said bar,   a longitudinal projection located under said flat part and that extends at least partially between said rear and front ends,   at least one wing positioned under said flat part, on a first side of said longitudinal projection,   wherein said wing extends from said longitudinal projection up to the bottom surface of said flat part and is provided with at least one lateral hollow-out bordered at the top at least partially by said bottom surface of said flat part, so that this lateral hollow-out, together with the lateral hollow-out of a wing of a first adjacent bar of said bar, forms a passage for channelling the air just below said flat part and up to said front end of said bar.   
   
   
       2 . A bar according to  claim 1 , further comprising at least one second wing that extends from said longitudinal projection up to the bottom surface of said flat part and that is positioned under said flat part, on a second side of said longitudinal projection, with said second wing being provided with a lateral hollow-out bordered at the top at least partially by said bottom surface of said flat part and, together with the lateral hollow-out of a wing of a second adjacent bar of said bar, forming a second passage for channelling the air just below said flat part and up to said front end of said bar. 
   
   
       3 . A bar according to  claim 1 , further comprising a multiplicity of wings distributed under said flat part along said longitudinal projection, on a first side or on each side of said longitudinal projection, with said wings extending from said longitudinal projection up to the bottom surface of said flat part and being provided with respective lateral hollow-outs outlined at the top at least partially by said bottom surface of said flat part, which, together with the respective lateral hollow-outs of the wings of the adjacent bar or bars of said bar, form passages, these said passages forming, on said first side or on each side of said longitudinal projection, a channel for guiding the air just below said flat part and up to said front end of said bar. 
   
   
       4 . A bar according to  claim 1 , further comprising at least one angled cutting element located under said flat part, on a first side of said longitudinal projection. 
   
   
       5 . A bar according to  claim 1 , further comprising a multiplicity of angled cutting elements distributed under said flat part, on a first side or on each side of said longitudinal projection. 
   
   
       6 . A bar according to either of  claim 4 , wherein each of said angled cutting elements is located firstly against the bottom surface of said flat part and perpendicularly to this bottom surface, and secondly against one or other side of said longitudinal projection and perpendicularly to this side. 
   
   
       7 . A bar according to  claim 1 , wherein the base of said front end of said flat part has an attack angle that is greater than 0°. 
   
   
       8 . A bar according to  claim 7 , wherein said attack angle is between 2° and 10°. 
   
   
       9 . A bar according to  claim 1 , wherein said front end of said flat part is provided, on at least one of the sides of said longitudinal projection with a fin for redirection of the air coming from said passage or passages, to at least one channel located in the top part of said front end of said flat part. 
   
   
       10 . A bar according to  claim 9 , wherein said channel starts at the bottom surface of said flat part and perpendicularly to said flat part, and opens out onto the top of the top surface of said flat part, parallel to said flat part. 
   
   
       11 . A grate for the firebox of an incineration furnace, wherein the grate includes at least one bar according to  claim 1 . 
   
   
       12 . A grate for the firebox of an incineration furnace, wherein the grate includes at least one group of three bars according to  claim 1 , with the central bar in said group being mobile in relation to the two lateral bars in said group. 
   
   
       13 . A grate according to  claim 12 , wherein said bars in at least one of said groups are assembled by means of a dowelling or pinning technique that locks the two lateral bars in relation to each other, and that leaves the central bar free in translation, between two extreme positions, in relation to the two lateral bars. 
   
   
       14 . A bar according to  claim 5 , wherein each of said angled cutting elements is located firstly against the bottom surface of said flat part and perpendicularly to this bottom surface, and secondly against one or other side of said longitudinal projection and perpendicularly to this side.