US1801275A - Steam boiler - Google Patents

Description

pr 21, 1931- p. s. JACOBUS 1,801,275

STEAM BOILER Original Filed July 2, 1918 INVENTOR. 49M. 91%., BY

A TTORNEYS.

Patented Apr. 21, 1931 Unrreo stares Artur curios DAVID S. JACQBUS, OF JERSEY CITY, NEW JERSEY, ASSIGNOR- TO THE BABCOCK &

WILGOX COMPANY, OF BAYONNE, NEVJ JERSEY, A CGELPOB ATIOH OF NEW J ERSEY STEAIII BOILER Original application filed July 2, 1918, Seria1 No. 242,890. Divided and this application filed June 29, 1923. Serial No. 643,432. Renewed September 4-, 1923.

My present invention relates to horizontal water tubes boilers in which a superheater is located between banks of such tubes and in which the headers for the superheater extend acrossthewatertubes,andmoreparticularlyto such arrangements in which the superheater headers form part of a bafile extending across the space between the banks of water tubes and the water tubes are arranged so as to minimize the slagging of the superheater tubes and its headers. Other objects of my invention will appear from the following description and the annexed drawing of an illustrative embodiment of my invention in which the figure is a sectional side elevation of a horizontal water tube boiler constructed in accordance with my invention.

In the drawing, 2 represents an upper bank of horizontally inclined tubes, and 3 a corresponding lower bank, shown as comprising six rows. The front and rear furnace walls are indicated by the reference numerals 40 and 11 respectively, the front wall being supported by a member 40 as indicated. The combustion chamber 4 below the lower set oftubes, extends substantially the entire length of the tubes and is of a hopper-shaped construction with the underfeed stoker 5 at the narrow part of the hopper, the front of the underfeed stoker 5 coming under the uptake headers 6, which may beeither sectional or of the box type. The rear Wall of the combustion chamber is provided with a door 4 through which a tool may be inserted to remove the clinker which collects over the stoker dump plates.

The lower ends of the upper bank of water tubes enter a group of headers 7 while the lower ends of the lower tubes 3 enter headers 8, these headers 7 and 8 being connected by long spaced-apart nipples 9. A baflie 10, disposed at the rear of the boiler, extends over the upper row of tubes 3 from the boxes 8 for a portion of their length, and from the inner end of this baffle a vertical baflle extends upwardly, being formed in part of the baffle 11 between the rows of tubes of the upper bank and in part of superheater headers 12, 12 12 and 12, and portions of baffling between them, the baffling being arranged to protect the headers from direct impingement of hot gases passing upwardly in the first pass. In the form shown the superheaters are provided with U-tubes 13 whose ends are connected to the boxes. It will be noted that the upwardly projecting part of this baffle extending through the bank is at an angle to the planes of theheaders such that the upward flow space is gradually contracted as the gases rise through the tubes after flowing along substantially the entire length of the lowermost tubes.

The steam from the steam and water drum 1% passes through. pipe 15 to the header box 12, thence throughthe U-tubes to the header box 12, whence it flows through nipples 12 into box 12 and thence through the longer U-tubes to the upper box 12", where it is taken off. The gases rise from the furnace through the lower group of tubes, pass up to the left of the battles until they rise through the upper group of tubes, and then flow down through the upper group of tubes and out between the nipples 9 to the ofi'take fiue 16.

In the form shown, a two-stage economizer is provided, the high pressure stage being shown at A and the low pressure stage at B. The waste gases from the boiler flow downwardly over. the high pressure stage, and thence horizontally over the low pressure stage B. The high pressure stage preferably comprises oppositely placed horizontally extending headers 17, connected by horizontally extending inclined tubes, the entire economizer arrangement being preferably in accordance with that shown in my Patent No. 1,281,016 issued October 8, 1918, for method of and apparatus for operating steam boiler economizers.

The low pressure stage is shown as consisting of three separate banks or groups of cast iron tubes, fitted into upper and lower cast iron horizontal boxes'or headers. The spaces between the banks provide for access to the tubes through ports shown at 20, and beneath each of the banks is a pit 21, for collecting steam condensed from the gases, or the water which may be used for washing the outside of the tubes. A scraper system 22 is also provided for removing any soot that may be deposited on the low pressure the high pressure stage,leaving the third bank through the pipe 24 leading to the tank '25. This tank is preferably provided with perforated plates, from which the water flows to facilitate the disengagement and escape of air and gases from the water, such disengagement being assisted by the heating of the water in the low pressure stage, and if desired, by maintaining a partial vacuum in the tank; by any suitable means, such as the dry vacuum pump 26; or the air and gases may be permitted to escape through the re lief valve 27 From the tank 25 the water is led by pipe 28 to feed pump 29, by which it is forced through pipe 30 to the lower part of the high pressure stage of the economizer. The water enters the lowermost header of the economizer, and thence flows through the inclined tubes from side to side, through successive rows, and is delivered by pipe 31 into the steam and water drum 1 1 of the boiler.

The advantages of my invention will be apparent to those skilled in the art. The two passes of the gases in the boil-er reduce the draft drop provided on the ordinary boiler of The Babcock & Wilcox type; the gases are discharged at a more convenient height for using economi'zers; the spacing apart of the headers where the gases pass through the connecting nipples provides an excellent space for the superheater.

By providing a relatively large flow area between the lowermost tubes and the proper number of tubes in the lowermost bank, a lesser amountof the slag will be deposited on the superheater, as a greater number of the fused particles of slag will be cooled in flowing through the spaces between the tubes to a degree that will cause them to be solidi-' fied before they come in contact with the superheater than would be the case with a smaller flow area and an insufficient number of rows of tubes. To secure good results, there should be at least four rows of tubes in the lowermost bank having at least twenty five per cent. of the total heating surface of the entire boiler, andthe lower bank should be unobstructed by baffles so as to provide a large flow areaofthe gases between the tubes and into the superheater chamber. The parti'cular arrangement, therefore, makes it possible to keep the superheater free from slag and to maintain a more even degree of superheat than could be secured with a lesser flow area between the tubes of the lowermost bank and lesser number of tubes in the lowermost bank.

The advantages derived through the form of combustion chamber shown Where the gases produced through combustion flow through progressively increasing areas in traveling through the furnace from the fuel bed vto the boiler tubes and contact with substantially the full length of the lowermost tubes, are that the gases are made to impinge against the lowermost boiler tubes in a reasonably uniform way throughout their length, thus distributing the heat from end to end of the tubes and avoiding local intensification of action at certain points through a torch-like effect of the flames. After distributing the gases by means of the special form of furnace so that they contact with the entire length of the lowermost tubes, the gases are directed forwardly by the roof baffie, after which they flow through progressively decreasing areas throughout the boiler, thus imparting a maximum amount of heat to the boiler with a minimum draft drop.

Building the front and'rear walls of the setting so as to make them incline outward from a point adjacent the stoker ledgeplates, as shown, is advantageous in maintaining the brickwork, as the weight of the Wall in itself holds the walls in alinement and prevents the walls from bulging inward. This element is important inconnection with'the high capacities at which boilers and furnaces are now beingoperated.

By extending the superheater boxes across the boiler with the superheater tubes parallel to theboiler tubes, an effective support is provided for the bafiie which extends across the superheater. chamber. It will be noted that, in the illustrative embodiment, this battle is :made up largely of the headers themselves, so that only a small portion of such baffle need be formed of refractories, and they are'in relatively small sections between the successive headers. This is advantageous because it avoids-the necessity ofadditional baffle supports extending across the space.

By exposing the superheater boxes to the gases, additional heating surface may be obtained in the superheater when the boxes extendacross the boilertubes. In the event that the superheated steam in any of the boxes is at a higher temperature than that of the gases, then, of course, such boxes would be protected by heat-resisting materials to prevent the passage of heat from the'boxes to the gases. By having the U-tubes parallel to the boiler tubes, any particular set of tubes may be withdrawn or replaced by making proper provision in the connections between the uptake headers for the two setsof tubes 2 and 3.

This application is a division of my. application, Serial No. 242,990 for improvements in steam boilers, filed July 2, 1918, and al-' lowed January 18,1923.

What I claim and desire to secure by Letters Patent of the United States, is:

1. A water tube boiler comprising a steam and water drum and having uptake and downtake water compartments connected by two banks of horizontally inclined Water tubes, the banks being spaced apart to provide a chamber between them, a furnace beneath the boiler, a superheater having the major portion of its tube-heating surface within that portion of the space between the water tubes adjacentthe uptake water oompartment, said superheater having tubes extending longitudinally of the water tubes and boxes or headers extending within the space between the water tubes transversely of the water tubes and located intermediate of the length of the water tubes and bathing comprising a longitudinal bathe above the lowermost tubes and extending from the low ends of the tubes to a point adjacent the superheater headers and a transverse bathe extending upwardly from the inner portion of the longitudinal bathe across the tubes of the upper bank and contiguous to the superheater headers and defining an upwardly decreasing fiow area for the gases across the tubes of said upper bank, said superheater headers forming a part of said transverse bathe, and the bathe having portions located in the space between the banks of water tubes and above the longitudinal bathe arranged to protect a superheater header above the lowermost header from direct impingement of hot gases passing upwardly in the first pass while said headers remain a portion of the heating surface.

2. A water tube boiler comprising a steam and water drum and having uptake and downtake water compartments connected by two banks of horizontally inclined water tubes, the banks being spacedapart to provide a chamber between them, a furnace beneath the boiler, a superheater having the major portion of its tube-heating surface within that portion of the space between the water tubes adjacent the uptake water compartment, said superheater having tubes extending longitudinally of the water tubes and boxes or headers extending within the space between the water tubes transversely of the water tubes and located intermediate of the length of the water tubes and bathing comprising a longitudinal bathe above the lowermost tubes and extending from the low ends of the tubes to a point adjacent the superheater headers and a transverse bathe extending upwardly from the inner portion of the longitudinal bathe across the tubes of the upper bank and contiguous to the superheater headers and defining an upwardly decreasing fiow area for the gases across the tubes of said upper bank, said superheater headers forming a part of said transverse bathe, and said bathing having portions located in the space between the banks of water tubes arranged to protect all of the superheater headers from direct impingement of hot gases passing upwardly in the first pass while said headers remain a portion of the heating surface,

3. A water tube boiler comprising a steam and water drum and having uptake and downtake water compartments connected by two bank of horizontally inclined water tubes, the banks being spaced apart to provide a chamber between them, a furnace beneath the boiler, a superheater having the major portion of its tube-heating surface within that portion of the space between the water tubes adjacent the uptake water compartment, said superheater having tubes extending longitudinally of the water tubes and boxes or headers extending within the space between the water tubes transversely of the water tubes and located intermediate of the length of the water tubes and bathing comprising a longitudinal bathe above the lowermost tubes and extending from the low ends of the tubes to a point adjacent the superheater headers and a transverse baffle extending upwardly from the inner portion of the longitudinal bathe across the tubes of the upper bank and contiguous to the superheater headers and defining an upwardly decreasing flow area for the gases across the tubes of said upper bank, said superheater headers forming a part of said transverse bathe, means for firing the boiler at the high end of the tubes, the rear end portion of the grate surface being below the longitudinal bathe, and the bathe having portions located in the space between the banks of water tubes and above the longitudinal bathe arranged to protect a superheater header above the lowermost header from direct impingement of hot gases passing upwardly in the first pass while said headers remain a portion of the heating surface.

4:. A water tube boiler having a steam and water drum and uptake and downtake water compartments connected by two banks of horizontally inclined water tubes, the banks being spaced apart to provide a chamber between them, a furnace beneath the boiler, a superheater having a major portion of its tube heating surface within that portion of the space between the water tubes adjacent the uptake water compartment, said superheater having tubes extending longitudinally of the water tubes and headers extenting within the space between the water tubes transversely to the Water tubes and located intermediate the length of the water tubes and bathing comprising a longitudinal bathe above the lowermost tubes and extending from the low ends of the tubes to a point adjacent the superheater headers and a transverse bathe extending upwardly from the inner portion of the longitudinal bathe across the tubes of the upper bank and defining an upwardly decreasing flow area'for the gases across the tubesof the upper bank, sa d superheater headers being subjected to the heat of the gases and said baffie havingta portion 10 cated in the space between the banks of Water tubes and above the longitudinal baflie arranged to' protect the superheater headers from the direct impingement of hot gases passing upwardly in the first pass While said 1 headers remain a portion of theheating surface.

DAVID S; J ACOBUS.

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