Dryer bar apparatus of a dryer

A dryer bar apparatus of a dryer for drying a web in a papermaking machine, said apparatus comprising:

• a rotatable dryer shell of cylindrical configuration, said dryer shell having an outer surface for drying the web;
• said dryer shell having an inner surface which defines an enclosure, said inner surface having a radius Ri;
• said enclosure being connected to a source of pressurized steam such that in operation of the dryer, a transfer of thermal energy from the steam within said enclosure through said inner surface of said dryer shell to said outer surface of said dryer shell is achieved so that the web is dried;
• a syphon disposed within said enclosure for controlling a layer of condensed steam accumulating adjacent to said inner surface of said dryer shell during operation of said apparatus;
• a number of turbulance bars disposed within said enclosure, each of said turbulance bars extending in a cross machine direction in contact with said inner surface, said bars being circumferentially spaced equidistantly around said inner surface of said dryer shell for generating turbulance within said layer so that uniformity of said transfer of thermal energy in said cross machine direction is maximized while said transfer of thermal energy through said dryer shell from said inner to said outer surface is minimized;
• and
• said number of turbulance bars being determined by the equation:
• N=int{2πRi/[4π(Riδ)1/2+W]}
• in which:
• N=said number of turbulance bars in said dryer shell;
• int=an integer number of a value in {} brackets;
• π=3.1415;
• Ri=said inside radius of said inner surface of said dryer shell in inches;
• δ=an average depth of said layer in inches;
• W=a width of each of said turbulance bars in inches.