US1274327A - Water-tube boiler. - Google Patents

Description

A. D. PRATT.

WATER TUBE BOILER.

APPLlCATlON men JUNE 16. IQIG Patented July 30, 1918.

2 SHEETS-SHEET I A. D. PRATT.

WATER TUBE BOILER.

APPLICATION FILED JUNE I6. I9l6.

1 374,827. Patenteqiiilslys 191s.

4 2 S IL 522. F1. 25.

IN VEN TOR.

/ ATTORNEYS.

UNITED STATES PATENT OFFICE.

ARTHUR D. PRATT, OF NEW YORK, N. Y., ASSIGNOR TO THE BABCOCK & WILCOX COM- PANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

WATER-TUBE BOILER.

Specification of Letters Patent.

Patented July 30, 1918.

To all whom it may concern:

Be it known that I, ARTHUR D. PRATT, a citizen of the United States, residing at New York city, borough of Manhattan in the county of New York and State of ew York, have invented certain new and useful Improvements in Water-Tube Boilers, of

which the following is a specification.

My invention relates to water tube boilers and will be understood by reference to the accompanying drawings in which Figure 1 is a vertical longitudinal section, more or less diagrammatic; Fig. 2 an enlarged view of a portion of Fig. 1; and Fig. an enlarged section on the plane of the line 33 of Fig. 1. Similar reference numerals indicate similar parts of the several views.

The present-day tendency is toward higher superhe'ats and one of the obJects of my invention is to meet this condition, in a standard, type of boiler, by placing the superheater in a zone of hlgher gas temperature. In-the standard Babcock & W11- cox boiler the superheater is placed above the of boiler tubes where, fora given boiler, there is substantially a constant gas temperature. According to the present de sign the superheater is placed below the bank of boiler tubes, and a suflicient number of water tubes are placed below the superheater in order to minimize heat absorption in the latter through radiatlon from the fire and the hot furnace walls. The superheator boxes are placed outside of the hot gas zone so that not only the boxes, but the hand-hole fittings will not be subjected to the action of the hot gases.

Referring to the drawings the numeral 1 designates a'bank of boiler tubes expanded into upper and lower headers 2 and 3, and divided by bafiles 4 and 5 into three transverse passes. The upper headers are connected by pipes 6 to steam and water drum 7. The lower headers are connected to saiddrum by nipples 8. A wall 9 is extended from the baffle 5 to the pipes 6, so

that the gases, after leaving the first pass at the steam uptake ends of the tube 1, will be directed downwardly and through the second pass. Below the main bank of tubes, and separated therefrom, is a row of tubes 10 connected to the headers 2 and 3. Supported upon this row of tubes, and extending from the lower headers to the baflle 4, is a bafiie 11. The space between the bank of tubes 1 and the row 'of tubes 10, below the second and third passes, is sufiicient to permit the entrance of a man to repair the bafile 11. Access to this space may be had through the door 12. i

The boiler may be fired by any suitable means, a chain-grate stoker being indicated at 13. Above the ignition arch is a crosswall 14, and at the rear of the primary combustion chamber 15 is a wall 16. Extending across the full width of the primary combustion chamber are rows of tubes 17 connected to short header sections 18 and 19, these latter being connected by nipples 20 and 21, respectively, to the headers 2 and 3. The tubes 17 are of such length as to project beyond the walls 14 and 16, sothat the header sections 18 and 19 will be outside of the hot gas zone. Above the water tubes 17, and in the space between said tubes and the water tubes 10, is a superheater 1, which in the form shown, comprises a series of U-shaped tubes 22 connected to boxes 23 and 24, and a series of similar tubes 25 connected to boxes 26 and 27. The planes of the superheater tubes are inclined and their junction with the boxes are on o posite sides of the lower nipples 21, as indicated 1n Fig. 3. The superheater boxes are outside of nipples 21 and of the plane of the headers 3, and thus outside of the hot gas zone, so that both the boxes and their handhole fittings 28 are not subjected to the hot gases. Steam is taken from the drum 7 through a pipe 29 to box 23, and after flowing through the tubes 22 passes from box 24 to box 26, thence through the tubes 25 to the outlet box 27. The nipples 20 are spaced apart sulficiently to admit a dusting lance for the purpose of cleaning the superheater tubes.

.The gases from the furnace flow from the primary combustion chamber across the water tubes 17 into the secondary'combustion chamber inwhich the su erheater is placed. The latter, therefore, a though in a lhe eneral arrangement of the water tubes 1s m rec groups, the lowermost compristhe main bank 1, and the intermediate group, the row of tubes As described,

the intermediate group is separated from both the lowermost and the uppermost I groups of tubes to provide an access space and a secondary combustion chamber.

What I claim and desire to secure by Letters Patent of the United States is 1. A Water tube boiler having horizontally extending tubes connected to upper and lower headers, said tubes being divided into separated groups, vertically extending nipples connecting the headers of the roups of tubes, and a superheater having hori'- zontal headers at different levels in front of the lower boiler headers and U-shaped tubes extending from the headers into the space it atween the groups of Water tubes, said l-shaped tubes embracing the nipples between which they extend and causing a parallel flow of the steam through the tubes from the header box at one level to .the header box at another level.

2. A Water tube boiler having horizontally extending tubes connected to upper and lower headers, said tubes being divided into separated groups, nipples connecting the headers of the groups of tubes, a superheater in the spacebetween said groups, said superheater comprising U-shaped tubes arranged With their legs extended between and beyond the front of the lower nipples, external cross boxes to Which the superheater tubes are connected, the flow of the gases being substantially unobstructed through the lower water tubes and supJerheater tubes, and the upper group'of tu es having baffling arranged to direct the gases in back and forth passes thereover.

In testimony whereof I have hereunto signed my name in the presence of two subscribing Witnesses.

ARTHUR D. -lPRA'lT.

Witnesses:

R. E. BUTLER, JOHN A. W. DIXON.

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