Hot plate for double facer for the production of corrugated board and double facer comprising a plurality of said plates

A double facer for producing corrugated board comprising:

• a heating section comprising a series of hot plates arranged in sequence along a feeding path of a continuous strip of corrugated board;
• and traction members for towing the corrugated board sliding along the hot plates;
• wherein each hot plate comprises an upper plate joined to a lower plate;
• wherein a heat transfer fluid circulation chamber is defined between the upper plate and the lower plate, with at least a first inlet for a heat transfer fluid and at least a first outlet of the heat transfer fluid;
• wherein the upper plate has a rectangular extension;
• wherein the upper plate is joined to the lower plate along two parallel sides of the upper plate;
• wherein the lower plate has, along said two parallel sides, two downwardly bent edges;
• wherein a plurality of stiffening ribs are joined to the lower plate, along the heat transfer fluid circulation chamber, and to the downwardly bent edges of the lower plate.