Forged-steel Cross Box
Where two or more drums are used in one boiler they are connected by a cross pipe having a flanged outlet for the steam connection.
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.
Inside Handhole Fittings
Wrought-steel
Vertical Header
Wrought-steel
Vertical Header
The tubes are expanded into headers of serpentine or sinuous form, which dispose the tubes in a staggered position when assembled as a complete boiler. These headers are of wrought 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 assembled boilers.
Opposite each tube end in the headers there is placed a handhole of sufficient size to permit the cleaning, removal or renewal of a tube. These openings in the wrought steel vertical headers are elliptical in shape, machine faced, and milled to a true plane back from the edge a sufficient distance to make a seat. The openings are closed by inside fitting forged 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 [Pg 51] binders and nuts. The joints between plates and headers are made with a thin gasket.
Wrought-steel
Inclined Header
Inside Handhole Fitting
Wrought-steel
Inclined Header
In the wrought-steel inclined headers the handhole openings are either circular or elliptical, the former being ordinarily supplied. The circular openings have a raised seat milled to a true plane. The openings are closed on the outside by forged-steel caps, milled and ground true, held in position by forged-steel safety clamps and secured by ball-headed bolts to assure correct alignment. With this style of fitting, joints are made tight, metal to metal, without packing of any kind.
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 made with a thin gasket.
