Furnaces – Doors and casings – Cooling
Reexamination Certificate
1999-01-21
2002-07-09
Ciric, Ljiljana (Department: 3743)
Furnaces
Doors and casings
Cooling
C110S17300B, C122S498000, C165S168000, C432S237000
Reexamination Certificate
active
06415724
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of industrial boilers and furnaces and in particular to a new and useful, high temp zone safety access door for steam generating boilers.
2. Description of the Related Art
Access doors to the interiors of steam generating boilers are used to enter a boiler for maintenance during downtimes in boiler operation. It is advantageous to place these doors at the level of the furnace or boiler floor. However, these regions of a furnace or boiler are often the hottest when combustion is taking place, since burners are positioned there for initial combustion.
Known access doors for furnaces and boilers have several drawbacks.
One prior door, originally sold by The Babcock & Wilcox Company, but no longer offered, was oval shaped and sized 15 inches by 21 inches. A cooling coil was sealed inside refractory material in the door. The coil covers only a fraction of the total area of the door, with refractory material occupying the remaining space. External hoses supplied boiler quality water to the cooling coil. Boiler-quality water is conventionally demineralized and deaerated to prevent corrosion of the metal tubes by contact with the high temperature water and steam. Even using boiler-quality water this door could not be used at extreme temperatures adjacent furnace and boiler burners for any length of time as the coil would tend to become overheated and/or blocked and reduce water flow and cooling capacity.
Another door currently produced by The Babcock & Wilcox Company is not water-cooled, but instead includes layers of refractory material and insulation. The door is a 22 inch diameter circular opening provided through a special break in the tube wall of a furnace or boiler. The door is intended to withstand temperatures between 2200° F. and 3100° F., however, it does not have a long service life at the extreme furnace and boiler temperatures found adjacent the burner positions.
These doors lack the ability to use untreated plant water to cool the door, as well as longevity in the hottest regions of the boiler or furnace, which may be between 2600° F. and 3300° F.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a safety access door for industrial furnaces and boilers which is easy to maintain and efficient to use and produce.
It is a further object of the invention to provide an access door for a furnace or boiler which is sufficiently wide to permit medical equipment such as a stretcher to pass through unobstructed.
Yet another object of the invention is to provide an access door which can withstand extreme furnace and boiler temperatures of between 2600° F. and 3300° F. in the regions adjacent burner zones.
Accordingly, an access door having a water-cooled jacket mounted on a door panel frame in a furnace or boiler wall is provided for use in high temperature regions of furnaces and boilers. The door is circular, preferably, with a diameter sufficiently large enough to permit a stretcher to pass through unobstructed, however, oval rectangular or square doors could be employed. The water-cooled jacket has a series of baffles which direct water in a serpentine path through the jacket. Plant water, as opposed to boiler quality water, may be used to cool the door. The jacket receives water from hoses connected to the top and bottom of the jacket at opposite ends of the serpentine path. Alternatively, multiple, separate flow paths for cooling water may be employed. A viewing port may be provided in the door as well.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.
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Albrecht Melvin J.
Aman James P.
Barkan James L.
DeVault Doiuglas J.
Ciric Ljiljana
Marich Eric
The Babcock & Wilcox Company
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