Furnaces – Combined – With boiler
Patent
1991-10-29
1993-10-26
Favors, Edward G.
Furnaces
Combined
With boiler
110165R, 110259, 110341, F23B 700
Patent
active
052556158
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a bottom ash discharge system for steam-producing boilers, which integrates and improves the apparatus for continuous dry removal of bottom ash described in the prior art European Patent No. 0 252 967 B1 of the same applicant, corresponding to U.S. Pat. No. 4,887,539.
In this European patent in fact an apparatus is described based on a conveyor belt able to withstand high temperatures and constructed so as to allow expansion in any direction, and consisting of two separate but joined elements which carry out separate functions of load support and of driving. This belt is enclosed in a tight sealed steel box applied to the boiler bottom, in such a way that the belt receives and discharges the ash continuously.
Since this apparatus functions excellently and already constitutes an optimum solution to the problem of dry extraction of bottom ash from boilers, it is considered that an ash interception system between the bottom of the boiler and the conveyor belt would be useful, in order to permit brief stoppings of the belt for maintenance, avoiding the direct falling of large lumps of collected ash onto the belt and eliminating the useless radiation of the belt when a polycombustible boiler is oil or gas fed.
The present invention resolves this problem perfectly in as much as it provides the joining of the extractor to the boiler by means of a transition ash feeder which is utilized as an accumulator and the bottom of which can be closed by a series of hatch valves.
This allows brief maintenance operations to be carried out on the extractor and in the machinery joined to it without having to interrupt the function of the boiler, given that the hopper constitutes an accumulator store of considerable capacity.
Furthermore the hopper with the hatch valves and the belt re-radiate the heat in the combustion chamber, contributing to increase the efficiency of the steam generator. This fact constitutes a notable advantage with respect to traditional wet, ash extraction systems where the combustion chamber, through a slit in the bottom looks on to a reflection of water in which the thermal flow is dispersed.
The intermediate position of semi-opening of the hatch valves, while it allows the passage of ash with normal granulometry, impedes the violent impact on the belt of lumps of larger size, and the presence of these large lumps of ash in the hopper are noticed by the operator who opens the valves completely thus provoking the directed fall on to the belt. The controlling can be carried out by any suitable means, for example an infrared telecamera.
In the prior art European patent 0 252 967 no specific treatment of the ash after its discharge from the extractor is described, and only the fact that a cyclically operated valve could be provided to limit or prevent the entrance of false air was mentioned.
In the system of the present invention, however, a predetermined quantity of outside air is used which, resucked by the negative pressure existing in the boiler, is passed in countercurrent to the ash and the belt, in this way the cold air exchanges heat with the system and the ash and feeds the combustion of the unburnt matter. This heat is reintroduced in the boiler contributing to increase the efficiency of the boiler and/or reduce the consumption of the combustible matter. The ashes, deprived of the unburnt matter, are transformed from a polluting product into a valuable and ecologically compatible component.
The present invention also provides, as a possible completion for the extraction process, a system of crushing and pneumatic transport of suitable ash to obtain bottom ash crushed to the point of being dispersable in the fly ash which is transported by smoke and deviated mostly by electrostatic precipitators.
Some types of coal and particular working conditions of the steam generator can provoke the formation of large agglomerates of ashes which precipitate irregularly on the bottom of the boiler.
These incrustations produce a reduced thermal exchange surface with the cooling f
REFERENCES:
patent: 1354553 (1920-10-01), Harter
patent: 1452952 (1923-04-01), Barnhurst
patent: 1506803 (1924-09-01), Astrom
patent: 1739497 (1929-12-01), Beach
patent: 2380264 (1945-07-01), Richardson
patent: 2558626 (1951-06-01), Pfau
patent: 2702485 (1955-02-01), Nadherny
patent: 3633737 (1972-01-01), Magaldi
patent: 3802584 (1974-04-01), Sackett, Sr. et al.
patent: 3841241 (1974-10-01), Dewey et al.
patent: 4020956 (1977-05-01), Van Hille
patent: 4112856 (1978-09-01), Fuhrman et al.
patent: 4284192 (1981-08-01), Taylor
patent: 4325478 (1982-04-01), Richard
patent: 4395958 (1983-08-01), Caffyn et al.
patent: 4432772 (1984-02-01), Starke et al.
patent: 4628828 (1986-12-01), Holtham et al.
patent: 4887539 (1989-12-01), Magaldi
LandOfFree
System for discharging bottom ash from steam-producing boilers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System for discharging bottom ash from steam-producing boilers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System for discharging bottom ash from steam-producing boilers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-951855