Part 4 (2/2)

The drued steel, faced, and fitted with taper thread stud bolts

[Illustration: Forged-steel Drum Nozzle]

Cross boxes by means of which the sections are attached to the drule sheet

Where two or more drums are used in one boiler they are connected by a cross pipe having a flanged outlet for the steaed-steel Cross Box]

The sections are built of 4-inch hot finished seamless open-hearth steel tubes of No 10 B W G where the boilers are built for working pressures up to 210 pounds Where the working pressure is to be above this and below 260 pounds, No 9 B W G tubes are supplied

[Illustration: Inside Handhole Fittings Wrought-steel Vertical Header]

The tubes are expanded into headers of serpentine or sinuous forered position when asseht steel or of cast iron, the latter being ordinarily supplied where the working pressure is not to exceed 160 pounds The headers may be either vertical or inclined as shown in the various illustrations of asseht-steel Vertical Header]

Opposite each tube end in the headers there is placed a handhole of sufficient size to per, reht steel vertical headers are elliptical in shape, e a sufficient distance to ed plates, shouldered to center in the opening, their flanged seats milled to a true plane These plates are held in position by studs and forged-steel binders and nuts The joints between plates and headers are asket

[Illustration: Inside Handhole Fitting Wrought-steel Inclined Header]

In the wrought-steel inclined headers the handhole openings are either circular or elliptical, the fors have a raised seat s are closed on the outside by forged-steel caps, ed-steel safety clanht,of any kind

[Illustration: Wrought-steel Inclined Header]

Where elliptical handholes are furnished they are faced inside, closed by inside fitting forged-steel plates, held to their seats by studs and secured by forged-steel binders and nuts

The joints between plates and header are asket

[Illustration: Cast-iron Vertical Header]

The vertical cast-iron headers have elliptical handholes with raised seats milled to a true plane These are closed on the outside by cast-iron caps ed-steel safety clas from the inside and which are secured by ball-headed bolts to assure proper alignht,of any kind

The mud drum to which the sections are attached at the lower end of the rear headers, is a forged-steel box 7 inches square, and of such length as to be connected to all headers by ht nipples expanded into counterbored seats Theclosed froed-steel plates with studs, and secured on a faced seat in the ed-steel binders and nuts The joints between the plates and the druaskets The mud drum is tapped for blow-off connection

All connections between drums and sections and between sections and mud drum are of hot finished seamless open-hearth steel tubes of No 9 B W G

Boilers of the longitudinal druht-steel supporting frames entirely independent of the brickwork

This allows for expansion and contraction of the pressure parts without straining either the boiler or the brickwork, and also allows of brickwork repair or reneithout in any way disturbing the boiler or its connections

[Illustration: Babcock & Wilcox Wrought-steel Vertical Header Cross Drum Boiler]

CROSS DRUM CONSTRUCTION--The cross druitudinal only in drum construction and method of support The drum in this type is placed transversely across the rear of the boiler and is connected to the sections bytubes expanded into bored seats