Grate Bar and Grate for a Step-Grate Stoker

Abstract

A grate bar and a grate for a stepped-grate furnace stoker. The grate bar includes a flat part whose top surface is used to receive the incinerated elements, and the extends into a rear end and a front end, each forming a return that acts as a support point for the bar. The bar also includes a longitudinal projection located under the flat part, and that extends at least partially between the rear and front ends of the bar. At least one angled cutting element or knife is located under the flat part, on a first side of the longitudinal projection, whose function is to facilitate the removal of the refractory materials that have accumulated progressively. The grate includes at least one bar or group of three bars. In the second case, the central bar in the group is mobile in relation to the two lateral bars.

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 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 angled cutting element located under said flat part, against and perpendicularly to a first side of said longitudinal projection,   wherein said angled element has a cross section in the shape of an essentially right-angle triangle, with firstly a first face essentially perpendicular to the bottom surface of said flat part forming a cutting angle, and secondly a second face forming an angle non perpendicular to the bottom surface of said flat part forming an expulsion angle.   
   
   
       2 . A bar according to  claim 1 , including at least one second angled cutting element located under said flat part, against and perpendicularly to a second side of said longitudinal projection, with said second angled cutting element having a cross section in the shape of an essentially right-angle triangle, with firstly a first face essentially perpendicular to the bottom surface of said flat part forming a cutting angle, and secondly a second face forming an angle that is not perpendicular to the bottom surface of said flat part, forming an expulsion angle. 
   
   
       3 . A bar according to  claim 1 , including a multiplicity of angled cutting element distributed under said flat part, against and perpendicularly to one or other of the first and second sides of said longitudinal projection, with said angled cutting elements having a cross section in the shape of an essentially right-angle triangle, with firstly a first face that is essentially perpendicular to the bottom surface of said flat part forming a cutting angle, and secondly a second face forming an angle that is not perpendicular to the bottom surface of said flat part, forming an expulsion angle. 
   
   
       4 . A bar according to  claim 1 , including at least one wing positioned under said flat part, on a first side of said longitudinal projection. 
   
   
       5 . A bar according to  claim 1 , wherein said wing is provided with at least one lateral hollow-out 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 up to said front end of said bar. 
   
   
       6 . A bar according to  claim 5 , including at least one second wing positioned under said flat part, on a second side of said longitudinal projection, with said second wing being provided with a lateral hollow-out which, together with the lateral hollow-out of a wing of a second adjacent bar of said bar, forms a second passage for channelling the air up to said front end of said bar. 
   
   
       7 . A bar according to  claim 5 , including 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 being provided with respective lateral hollow-outs which, together with the respective lateral hollow-outs of the wings of the neighbouring bar or bars of said bar, form passages, with said passages forming, on said first side or on each side of said longitudinal projection, a channel for guiding the air up to said front end of the said bar. 
   
   
       8 . A bar according to  claim 5 , wherein said passage or passages are outlined at the top at least partially by the bottom surface of said flat part, so that the channelled air circulates just below said flat part. 
   
   
       9 . 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°. 
   
   
       10 . A bar according to  claim 9 , wherein said attack angle is between 2° and 10°. 
   
   
       11 . 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. 
   
   
       12 . A bar according to  claim 11 , 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. 
   
   
       13 . A grate for the firebox of an incineration furnace, wherein the grate includes at least one bar according to  claim 1 . 
   
   
       14 . A grate for the firebox of an incineration furnace, wherein the grate includes at least one group of three according to  claim 1 , with the central bar in said group being mobile in relation to the two lateral bars in said group. 
   
   
       15 . A grate for the firebox of an incineration furnace according to  claim 14 , wherein each angled cutting element on one side of a central bar is symmetrical and offset in relation to the angled cutting element, on the side of a lateral bar, with which it mates when the central bar is in movement in relation to the lateral bar. 
   
   
       16 . A grate according to  claim 14 , 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.