Patent Number: 
Section: claims

1. In a heat exchanger tube and shell structure, a generally flat support plate having a plurality of individual tube receiving apertures formed therein, at least three members integral with the plate defining each of the apertures, the integral members protruding inwardly toward the center of the respective aperture and forming bights between at least adiacent pairs of the members in order to provide a predetermined flow area when the tube that is individual to the respective aperture is lodged in place, the flow area having an inlet and an outlet, the members having beveled and sections at the inlet and the outlet, the inwardmost end of each of the integral members forming a flat land, said protruding integral member flat lands restraining but not all contacting the outer surface of the individual tube that is to be received within the respective aperture. 2. A heat exchanger tube and shell structure according to  claim 1  wherein each of the apertures has an hourglass configuration. claim 1 3. A heat exchanger tube and shell structure according to  claim 1  wherein the beveled end sections have a chamfer angle of about 11 degrees. claim 1 4. A heat exchanger tube and shell structure according to  claim 1  wherein the inwardmost end of each of the integral members includes a tube contact section formed between the beveled end sections. claim 1 5. A heat exchanger tube and shell structure according to  claim 4  wherein the tube contact section is about 0.75 inches in length. claim 4 6. A heat exchanger tube and shell structure according to  claim 1  wherein the plate is formed from SA-240 410S stainless steel material. claim 1