Abstract: A combustion apparatus and process for improved flue gas recirculation wherein the recirculation line penetrates into an exhaust duct, such as the exhaust stack for capturing and directing a portion of said flue gas through the recirculation line which is connected to an air fan inlet which provides induction of the flue gas into the combustion unit. The portion of the recirculation line that extends into the exhaust stack is preferably aerodynamically configured to capture a portion of a flue gas stream without detrimental impedance of the gas flow.

Abstract: A combustion apparatus which has a post combustion hot gas fan and a recirculation duct positioned down stream from the fan to reduce NOx emissions by returning a portion of the exhaust from the combustion zone back to the combustion zone. For example, in one embodiment the increased velocity of the exhaust gas stream from the post combustion hot gas fan which is required to overcome the pressure drop in a post combustion treatment unit is used as the motive force for the recirculation of a portion of the exhaust to the combustion zone to reduce the NOx exiting the apparatus to a level below that of the post combustion treatment alone.

Abstract: This invention relates to a wide angle viewing system (V) which may be inserted into a high temperature environment, in particular, a furnace or burner (F). The superior interior wide angle view (A) yields pertinent information for use in diagnosing combustion problems. The access to the interior from the outside is variable from one furnace or burner to another. The viewer, therfore, was designed so that the wide angle view is retained regardless of the distance (D) the observer (O) must be from the outside to the interior. The wide angle viewer is simply affixed to the end of a pipe or tube (24) of sufficient length to reach to the interior (26), and then inserted into the interior (26) where the observer (O) looks into the rear end (24r) of the pipe to view the interior (26). Photographic equipment may also be installed at the rear end of the tube to provide a pictorial documentation of the interior (26).

Abstract: A lettering kit and release alignment grid therefor with the lettering kit including pressure sensitive adhesive backed letters and Arabic numerals in a specific font style and supplied in precut form mounted on backing sheet that is release agent coated for readily removal of selected letters and numbers to form desired words and phrases that are to be transfer applied to a desired substrate surface to form signs or the like, in which a special lay out, release agent coated; grid is provided that has guideline indicia keyed to the special shaping of the individual capital letters, lower case letters, and numerals that the font style conventionally has, for layout of the desired word or phrase on the grid to achieve, for transfer to the substrate surface, professional printing appearing letter alignment and spacing in individual word or phrase units, for pickup and transfer as a unit to the substrate surface, using a transfer sheet having a special pressure sensitive coating for this purpose.