Straight long wave infrared rays can be easily arranged to fall on an object by use of a refection plate. If the cross-section of the refection plate is designed in parabolic shape, most of the refected rays will go in parallel direction to heat to the object.
Alumunium plate has excellent refective power. Stainless plate is slighty inferior to alumunium plate while stainless plate must be used where corrosive gas emerges.
There is a 30% difference in effciency between the use of parabolic refection plate and a plane type. Therefore a parabolic refection plate should be used whenever it is possible. For maintaining the effciency of the refector, periodical cleaning