Grate bar for a furnace comprising air ducts

A grate arrangement for a furnace, the grate arrangement comprising:

• a first grate bar, the first grate bar including
• a front end,
• a back end distal from the front end,
• an upper surface extending from the front end to the back end,
• a lower surface extending from the front end to the back end and distal from the upper surface, and
• a first lateral side defined between the upper surface, the lower surface, the front end, and the back end, the first lateral side defining first grooves extending from top openings in the upper surface to bottom openings in the lower surface, wherein the first grooves are inclined in the first lateral side with the top openings positioned towards the front end of the first grate bar relative to the bottom openings;
• a second grate bar, the second grate bar horizontally adjacent to the first grate bar, the second grate bar including
• a front end,
• a back end distal from the front end,
• an upper surface extending from the front end to the back end,
• a lower surface extending from the front end to the back end and distal from the upper surface, and
• a second lateral side defined between the front end, the back end, the upper surface, and the lower surface, the second lateral side facing the first lateral side of the first grate bar, the second lateral side defining second grooves extending from top openings in the upper surface to bottom openings in the lower surface, wherein the second grooves are inclined in the second lateral side with the top openings positioned towards the back end of the second grate bar relative to the bottom openings, and wherein an intersection of the first grooves with the second grooves defines a conveying volume;
• and
• supporting members configured to support the first and second grate bars and configured to generate a relative motion between the horizontally adjacent first and second grate bars between a first position and a second position, wherein at the first position, the top openings of the first grooves intersect with the top openings of the second grooves to define the conveying volume, and wherein at the second position, the bottom openings of the first grooves intersect with the bottom openings of the second grooves to define the conveying volume.