Improvements in the Manufacture of Wrought Metal Cross Boxes or Saddles for Sectional Steam Generators, and in Apparatus therefor.
Year: 1890

page_text: Date of Application, 3rd Apr., 1890-Accepted, 17th May, 1890
COMPLETE SPECIFICATION
Improvements in the Manufacture of Wrought Metal Cross Boxes
or Saddles for Sectional Steam Generators, and in Apparatus
therefor.
We, CHARLES ALBERT KNIGHT of 107 Hope Street in the City of Glasgow
Engineer and CAMPBELL PECK HIGGINS, of Kilbowie, Dumbartonshire, Engineer,
do hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:—
This invention relates to the manufacture of wrought metal cross boxes or saddles
of the kind described in the Specification of Letters Patent No. 17804 of 1888 as
constructed for attachment to the steam and water drum or reservoir of a sectional
steam generator of the well known Babcock and Wilcox type and the invention
comprises improved apparatus specially designed to press out or dish and shape
wrought metal plates in such manufacture.
In forming a cross box or saddle of the kind referred to according to this
invention a flat wrought metal plate is after suitable heating subjected to pressure
by a series of dies which may be fitted in one or a number of hydraulic or other
power actuated presses and which operate in succession upon the plate to gradually
impart to it the requisite formation without weakening or damaging the plate.
In the accompanying drawings which illustrate the invention figures 1, 2, 3, 4
and 5 are vertical sections of part of a hydraulic press showing the dies in different
positions acting upon a plate, figure 6 is a plan of figure 3, figure 7 a vertical section
at right angles to figure 3 and figure 8 a plane of figure 7. These dies impart to
the plate pressure to dish or bump out the parts forming bulges or pocket-like pro-
jections near each end of the plate and appearing at A, A, of the cross box or saddle
piece which is represented as finished in elevation at figure 9 and in section at
figure 10. Figures 11, 12 and 13 show the different positions of the shaping dies
employed to further press the plate after the pocket like bumps are formed, figure 14
is a sectional plan of figure 13, figure 15 a cross section and figure 16 an end elevation
of the same. Figures 17, 18 and 19 are respectively sectional side and end elevations
and a plan of a finishing die by means of which the flanges formed for attachment of
the cross box to the drum are pressed to the exact contour required.
The starting dies represented at figures 1 to 8 of the drawings are composed of a
dishing die block B and a series of concentrically situated rings C, C, C, between
which and the die block the plate is pressed the rings being fitted over or formed on
the beads of a series of telescopic rams or plungers D, D1, D2, fitted within a
cylinder E over which is bolted a casing F surrounding the rings.
The die block B, is in the present instance of conoidal form and the rings C, C, C³,
when in the position represented at figures 1 and 5 form a conical series the upper
inner edges constituting bearing surfaces against which the under face of the plate
bears when by pressure of the dies the dishing operation is effected.
In the operation of the press one end of the heated plate to be dished or bumped is
laid on the top of the casing F, and the die block B, is depressed to the position
shown at figure 2 whereby the plate is dished. The lower dies are then forced up
to the position indicated at figures 3 and 7 whereby the plate is closed against the
upper die block B thus completing the dishing operation at one end of the plate.
The other end of the plate is then acted on in a similar manner or both ends may be
dished simultaneously by forming the press with two sets of dies at suitable
distances apart. If a greater depression is desired one or more of a series of
stop discs G, fitted on the die block B, is or are removed in order that when
further pressure is applied the upper die block may be brought down close upon the
dished plate. In this case the plate is reheated and placed over the casing F as
017

page_text: indicated at figure 4 and then pressure is applied to force the dies together whereby
the plate is drawn by the die block pressing on the crown until it assumes the form
represented at figure 5 the depth of the bump or depression being determined by the
number of stop discs used on the die block.
The plate after being dished or bumped near its ends as above described and
reheated is placed in the press represented at figure 11, and in the position therein
indicated the heated plate resting on a die block H, on the lower platen of the press
and having placed over it a creasing piece composed of two blocks I, I, having
curved acting faces at i, i, and jointed to a central die block J having a similarly
curved acting facej.
A removable stop piece K is placed between the die J, and the top sill of the
press and pressure is applied to bring the dies together whereby the plate is pressed
to the form indicated at figure 12 the parts of the dies being prevented from closing
entirely by the stop K. The dished bumps A, are thus partially drawn into position
over removable blocks or projections h, on the die H, the upper faces of said projec-
tions being in line with a flattened recess on the upper face of the die block H and
serving with said flattened recess and a correspondingly flattened piece jl on the
block J to form the straight channel a constituting the tube seat of the cross box.
The pressure is then relieved to enable the stop K to be removed and pressure is again
applied whereby the dies are closed on the work at all points as indicated at
figure 13.
This final pressure gives the cross box its form which corresponds to the cylindrical
contour of the drum to which it is to be rivetted. The rough edges are then trimmed
and the box so formed is reheated and placed in the finishing die represented at
figures 17, 18 and 19 whereby the flanges are smoothed and brought to the proper
contour by means of flanged edges L forined on said die.
The use of the finishing die may be obviated by ensuring that the box is brought to
the proper contour of the drum to which it is to be fitted by means of the creasing
dies as represented at figure 13. As by the arrangement therein shown the dies may
not in every case sufficiently close on the work to finish it we propose to apply side
pressure by rams or otherwise on the die blocks I I.
In forming boxes or saddles of small size and in which the extent of bumping is
slight as indicated by figures 20 and 21 the plate is or may be pressed to the required
formation at a single operation by the use of die blocks shaped to correspond to the
contour of the box.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. The manufacture of wrought metal cross boxes or saddles for sectional steam
generators substantially as herein before described.
2. The method or process of forming wrought metal cross boxes for sectional
steam generators consisting in first dishing or bumping a plate by a series of dies to
form bulges or pockets near its ends and thereafter subjecting the dished plate to
pressure between dies to successively form a tube seat channel and bend the plate to
the contour of a cylindrical drum substantially as described.
3. In-a-press-for-dishing or bumping metal plates the combination of a series
of ring dies operated by telescopic rams and a central conoidal die block adapted
to partially enter said rings in acting on a plate placed between the dies substantially
as described.
4. In a power actuated press the combination of the ring dies C, C1, C2, rams
or plungers D, D1, D2, cylinder E and casing F, with the die block B, provided
with stop discs G, substantially as and for the purpose set forth.
5. In apparatus for shaping wrought metal plates to form cross boxes or saddles
for sectional steam generators the combination of a lower die block provided with
tube seat blocks and a jointed upper creasing die operating to bend the plate to the
contour of the drum substantially as described.

page_text: 6. In apparatus for shaping wrought metal plates to form cross boxes or saddles for
sectional steam generators the combination of the die block H, h, with the jointed
creasing die I, J, and the stop piece K substantially as and for the purpose set
forth.
7. In apparatus for forming cross boxes or saddles for sectional steam generators
a finishing die constructed to operate as described with reference to figures 17, 18,
and 19 of the annexed drawings.
Dated this Second day of Anril 1800.
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow, Agents.