US2340086A - Steam generating and superheating installation - Google Patents

Description

Jan. 25, 1944. 1.. c. SOUTHCOTT 2,340,036

STEAM GENERATING AND SUPERHEAT ING INSTALLATION Filed Oct. 17, 1941 IINVENTOR.

BY Zeonald Jaw/k0 g ATTORNEY Patented Jan. 25, 1944 i STEAM GENERATING AND SUPERHEATIN INSTALLATION 1 Leonard Clement Southcott, Bowdon, Altrincha n,

England, assignor to The superheater Company, New York,..N. Y., a corporation of Delaware Application October 17, 1941, Serial No. 415,378

' In Great Britain October 8, 1940 1 Claim. (01. 122-473) This invention is concerned with steam 'generating and superheating installations.

Steam generating and superheating installations are known in which the generator hasupper and lower drums connected by appropriately baflled banks of bent water tubes with the space between the banks comprising two water cooled furnaces, there being uptakes at each side of the upper drum or drums, with convectively heated superheating elements suitably disposed in the boiler. Such a boiler may be termed doublesided.

Single-sided bent tube boilers also are known having asingle bank of water tubes appropriately baflled and connecting upper and lower drums, with a single furnace bounded by water cooled walls and the said tube bank, such a boiler having a convectively heated superheater associated with its tube bank.

Boilers of the general kind indicated above are noted for their rapid steaming, and the present invention seeks to provide a bent tube boiler of such general kind in which a high degree of superheat, or both superheat and reheat, ay be obtained and the superheat temperature, or both superheat and reheat temperatures, be controlled in a simple and efficient manner.

Broadly stated the invention consists in a boiler having upper and lower drums connected by water tubes arranged to form main and subsidiary banks with two water cooled furnace chambers between them, each with its own uptake, and between the furnaces a superheater adapted to be heated by products of combustion passing from the main furnace remote from the main bank into the auxiliary furnace nearer the said bank, there being another vapour heater disposed in the said main tube bank, and the steam temperature being controlled by regulating by means of dampers in the respective uptakes the proportion of the gases from the main furnace which flows over the superheater between the furnaces and into the auxiliary furnace and main tube bank, relatively to the proportion which flows to the uptake directly associated with main furnace.

In carrying the present invention into practice, the vapour heater located in the main tube bank of the boiler may be either a superheater in series with that between the furnaces, or a reheater; where a second superheater constitutes said vapour heater, control of the final steam temperature may be effected partly by proportioning the flow of gases from the main furnace to the respec tive uptakes, and thus varying the quantity flowmg over the superheater between the furnaces, and partly by regulating the firing of the auxiliary furnace to control the gas'iiow over such second superheater. v

To define the two furnaces in the furnace space of the boiler a division bafile is provided, the superheater disposed between the furnaces being arranged at the main furnace side of the baffle. This baffle, while being arranged to permit the flow of gases from the main furnace into the auxiliary furnace, is also such as to cause the gases to flow over the elements of the superheater lying between the furnaces on their Way to the auxiliary furnace and main tube bank.

In the accomlpanying drawing- Figure 1 is a sectional elevation and Figure 2 a sectional plan of a boiler with superheating arrangements according to a selected em bodiment of the invention, the illustrations being more or less diagrammatic and Fig. 1 being a section on the line l-I, Fig. 2, while the latter figure is asection on the line 22, Fig. 1.

Referring to the drawing, the steam and water drum 2 is connected toa waterdrum disposed beneath it by bent water tubes forming a main tube bank 3 and a subsidiary tube bank 4. A superheater 5 lies in the furnace space between the tube banks, and another vapour heater 6, for example a rheater, is disposed in the main tube bank 3.

The furnace space is divided by a water cooled baflle into two chambers constituting a main furnace 1 remote from the main tube bank 3 and an auxiliary furnace 8 nearer said bank, the furnaces being fired by burners at 9 and I0 respectively, in one end wall of the furnace space. The end walls would be cooled by any convenient arrangement of water tubes (not shown).

In the embodiment of the invention illustrated the division bafile l l between the furnaces is formed of refractory material supported by vertical water tubes l2, such baffie extending from one end of the boiler an appropriate distance towards the other end, and between the convectively heated superheater 5, lying adjacent said baffle, and the main furnace 1 one or more rows of spaced vertical water tubes I3 is or are arranged, the latter water tubes and those supporting the baffle being available to afford support to the superheater elements. Alternatively, water tubes in contact may be employed, instead of refractory material, to form the division bafile.

Associated with the furnaces I, 8 are uptakes [4, I5 respectively, controlled by dampers l6, l1. Gases from the furnaces can flow directly to lated to control the temperature of steam delivered by the reheater 6.

Usually to obtain maximum steam temperature damper l6 would be closed and damper I1 fully opened, whereby the whole of the products of combustion from the main furnace I would flow over the superheater 5. 7

To raise pressure in the boiler the main furnace I only would be fired and the products of combustion therefrom would be passed over the subsidiary tube bank 4 to the uptake l4 associated therewith, the damper I! in the uptake [5- associated with the main tube bank 3 being closed. When sufficient steam is available to protect the elements of the superheaters, or superheater and reheater 5, 6 from overheating the damper H associated with the main tube bank 3 will be opened and gases from the main furnace will flow over the main bank, the damper I6 appertaining to the subsidiary bank 4 being closed, or partially closed. At the appropriate time the auxiliary furnace 8 would be fired and the final steam temperature; or the final steam and reheat temperatures, will be controlled as already indicated by regulating the gas flow over the superheaters, or superheater and reheater, by adjusting the dampers, and also by regulating the firing of the auxiliary furnace.

A boiler and vapour heating installation con structed as described enables the boiler to oper- 3,340,03 1. f if. $11 6:

ate to give a relatively large output of saturated or low temperature steam by firing only the main furnace 1 and passing all the products therefrom over the subsidiary tube bank 4, the damper l1 associated with the main tube bank 3 being closed.

What I claim is:

- In a boiler having two separate gas offtakes; means forming communicating main and auxiliary furnace chambers below said ofitakes each communicating directly with one of the latter; a superheater located between said furnaces; banks of steam generating tubes located between the respective furnaces and the oiftake adjacent thereto; bafile means positioned between said superheater and said auxiliary furnace chamber so arranged as to shield the superheater from said auxiliary chamber while permitting gases from said main chamber to enter said auxiliary furnace chamber and pass over the tube bank and to the ofitake which are related thereto; fuel burning means associated with said main furnace chamber providing the major portion of the heat utilized in'generating steam in both said tube banks and all of the heat absorbed by said superheater to superheat the steam; other fuel burning means associated with said auxiliary furnace chamber providing the remainder of the heat required for absorption in the tube bank between it and its ofitake for generating steam in said boiler; and damper means in said ofitakes operable to regulatethe amount of gases passiiig'from said main furnace chamber to the offtake therefor in relation to the amount passing from, said chamber over said superheater into said auxiliary chamber to be discharged through the offtake for the latter.

LEONARD CLEMENT SOUTHCOTT.

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