Corner foils for hydraulic measurement

A fluid flow pressure measurement system having a corner air foil arrangement for channeling a fluid flow through a bend of a rectangular duct of a furnace, the arrangement for creating a region within the bend, having increased fluid velocity which is suitable for obtaining accurate pressure measurements, the system comprising:

• an outer duct bend wall having a flat, straight portion between two arcuate portions, the wall forming a bend;
• an inner duct bend wall having an arcuate portion forming a bend, the arcuate portion defining an arc of a circle having a center outside the duct bend;
• a pair of flat duct side walls airtightly connecting the outer duct bend and inner duct bend at a constant distance apart;
• an inner corner air foil having a bottom surface continuously connected to the inner duct bend wall between the side walls, an outer surface, a leading edge, and a trailing edge;
• at least one corner air foil attached to the pair of side walls within the duct bend, oriented substantially parallel to the outer duct bend wall and between the outer duct bend wall and inner duct bend wall, each air foil having a leading edge, a trailing edge, and at least one substantially straight section between the leading edge and the trailing edge forming at least two substantially straight channels between the at least one substantially straight section, the outer duct bend wall and the inner corner air foil within the duct bend;
• and
• means, located within the at least two substantially straight channels, for measuring a static and a dynamic pressure of the fluid flow through the channels.