AN IMPROVEMENT OR IMPROVEMENTS IN THE STEAM ENGINE
Year: 1832

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
REDMUND, of Charles Street, City Road, in the Parish of Saint Lukes, in the
County of Middlesex, Engineer, send greeting.
WHEREAS His most Excellent Majesty King William the Fourth, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Eighteenth day of October, in the third year of His reign, did
give and grant unto me, the said David Redmund, my exors, adiñors, and
assigns, His special licence that I, the said David Redmund, my exors, admors,
and assigns, during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England, Wales, the Town of
Berwick-upon-Tweed, my Invention of "AN IMPROVEMENT OR IMPROVEMENTS IN
THE STEAM ENGINE;" in which Letters Patent there is contained a proviso,
obliging me, the said David Redmund, under my hand and seal, to cause a
particular description of the nature of my said Invention, and in what manner
the same is to be performed, to be enrolled in His Majesty's High Court of
Chancery within six calendar months next and immediately after the date of
the said recited Letters Patent, as in and by the same (relation being there-
unto had) may more fully and at large appear.
NOW, in compliance with the said proviso, I do hereby declare that my said
Invention consists in certain improvements in the form and arrangement of
parts in that part of the steam engine called the boiler, which is employed to
generate steam, for the purposes of working the same; and the nature of my
said Invention is ascertained and set forth in the following description, reference*

page_text: being had, for more fully illustrating and explaining the same, to the Drawings
hereunto annexed :-
In these Drawings the same parts are referred to in the description by the
same marks, letters, or numeral figures, and the scale or scales are indicated
upon the Drawing.
My steam boiler is constructed in the following manner:-It consists of a
series of separate chambers placed side by side, communicating with each other
through tubes which afford a common passage to all the cavities for water and
for steam, and. the chambers are held in contiguity with each other by an outer
common casing, composed of plates, bolts, and bars. The general arrange-
ment of the chambers is seen at Figure (Fig. 1); all the chambers are of similar
form. Each chamber consists of two side pieces, a top and a bottom piece, the
ends being formed by the returned margin of the side pieces. I construct the
side pieces which form the walls of the chambers of rolled sheets of copper,
iron, or other suitable metal, and I give to these sheets a corrugated or fluted
form by means of rollers, stamps, or other efficient means, so that they present
on the exterior surface a close, succession of nearly semi-cylindrical channels
or hollows, running in the vertical direction of the sides of the chamber, the
metal being doubled or bent to a sharp curve betwixt each semi-cylinder.
These semi-cylindrical and sharp curves of the plates are seen in section at
Figure (Fig. 1), letters (a, a, a,) and (b, b,,b). The sides of the chambers are
thus composed of a series of parallel arches, which, when their abutments are
duly supported, are capable of resisting great internal pressure. I describe and
delineate the flutings of the. side plates as forming a series of nearly semi-
cylindrical hollows, and I do this as being generally the most appropriate form;
but I do no tthereby mean to restrict the flutings to this particular incurvation,
as I reserve to myself the right to adapt any other modification of curve, or
even to make the flutings approximate to flat-sided angles. In arranging the
two side pieces of a chamber in reference to each other, the flutings may have
any relative position at pleasure; but I prefer to place them so that the promi-
nences of one side stand opposite to the hollows of the other, as is shewn in
the section (Fig. 1, c, d). The ends of the chamber are formed by marginal
strips of the side pieces left flat, being bent over at right angles to the general
line of the side, and overlapping one another; the two side pieces are here
rivetted together, shewn at (e, e, e). The bottom piece of the chamber I make
of cast copper, iron, or other suitable metal, in the form of a shallow trough,
the sides of which are indented or incurvated correspond exactly with the
flutings of the side pieces, fitting accurately within their lower margins. The
lower edges of the side pieces stop upon a ledge cast on the outside of the
"

page_text: trough, seen at (Figs. 2 and 3). The bottom piece is attached to the side
pieces by rivets, as shewn at (9,g, Figs. 1, 2, 3). The side pieces and bottom
being rivetted together, the ledge cast round the bottom may be caulked, so
as to make the joint steam-tight, and the projection serves to protect the
seam from the direct action of the fire. The hollow of the trough I slope
down to a middle line at the bottom, for the purpose of collecting there
such sediment as may be deposited, so that it may be readily removed
through openings made for that purpose. The top pieces of the chambers
are likewise of cast metal, being of the form of shallow troughs with
indented sides, correspondent with the flutings of the side pieces, and with
flat bottoms. The top pieces fill accurately the space between the sides,
and are attached to them by rivets, passed through the sides, as shewn at
(h, h, Fig. 2, 3.) When the chambers constructed in the way now described
are placed side by side in close contact, the hollow fluting in the sides,
corresponding in situation in the contiguous chambers, form together open
spaces running vertically betwixt the chambers, which serve as flues for the
passage of the heated air from the fire; the flues so formed are seen in section
at (i, i, Fig. 1). For the purpose of affording a common supply of water to the
cavities of all the chambers, a tube (k, Fig. 1,) to be connected with the force
pump, has branch pipes (1), which pass into each chamber through the flat end
of the cast bottom piece.
To effect a communication betwixt the upper portions of the cavities of the
chambers, a tube of from two to three inches diameter; made of cast copper,
iron, or other suitable metál; is placed across the tops of all the chambers,
häving cast on its under side as many bosses as there are chambers. Through
these bosses and through the flat surfaces of the chamber tops screw cocks are
inserted, the joints being made steam-tight by copper washers. See (m, m
Fig. 2). This tube forms a steam communication betwixt the chambers; from
it the supply pipe for the cylinder is conducted, and into it the safety valves are
inserted. For the purpose of ascertaining the depth of water in the boiler, a
vertical pipe or pipes, having guage cocks and communicating with the upper
and lower parts of the chambers, is or are placed in a situation to be' readily got
at by the engineer. The feed pump should be so regulated as to keep the boiler
about one-third full of water, the remaining two-thirds of cavity serving as a
steam chamber. The casing of the boiler which holds the chambers in contact
with each other consists of four strong plates of metal covering the four sides;
and held together by bolts, braces, and bars, so as to compress the chambers
strongly together: The strength of the casing should be calculated to be of
three or four times the strength of the boiler plates. The casing should be

page_text: protected from the action of the fire by a coating of Stourbridge clay or road
scrapings. The boiler which I have described may be set over any fire-place
of ordinary construction, so arranged, however, as that the flues formed betwixt
the sides of the contiguous chambers form the only vents for the passage of
flame and heated air from the fire. But when my boiler is used for a steam
locomotive carriage, to which purpose I consider it peculiarly adapted, I prefer
to use a fire-place, the bars of which are hollow tubes of iron bent to a semi-
eliptical form, as seen at Fig. 4, n. Cylindrical tubes made red hot may be
brought to the form shewn in section at (o, Fig. 5,) by being passed through
rollers, or other forms deemed more suitable may in the same way be given them.
I would place one of these hollow bars under each chamber of the boiler, having
them of such diameter as to leave about an inch clear betwixt the bars.
Beneath these bars, across the middle of them, I would place another tube, about
four inches diameter, with bosses on it, to be connected with the hollow fire bars
by bolt screw cocks, as shewn in (p, p, Fig. 5.) The spent steam should then
be turned into the four-inch tube, and it would pass through the fire bars, from
which it may be allowed to escape by a number of small holes drilled on their
under side, or by any other aperture elsewhere situated. More effectually to
protect the fire bars it may be deemed useful to keep them filled with water
instead of the spent steam, in which case the steam may be turned into the ash
pit, and provision must be made to connect the cavities of the fire tubes with
that of the chambers. The dimensions, proportions, and strength of my boilers
may be varied according to the different sizes of engine they are designed
to work. The dimensions, proportions, and strength of parts indicated by the
Drawing hereunto annexed, made of full size, in section, at (Figure 1), I con-
sider to be equal to supply steam to a cylinder about seven inches diameter and
twelve inches stroke, working at a pressure of one hundred pounds to the square
inch in the boiler.
Having now described my present improvements in the boilers of steam
engines, and shewn how the same are to be executed conformably to the
proviso in my said Letters Patent to that end made and inserted, I now
declare that my Invention consists in the formation of channels, flutings, or
longitudinal hollows, in the sides of the several chambers of which the boiler
consists, so placed and arranged as that when the chambers are brought toge-
ther in their proper situations, the said channels, flutings, or hollows on the
sides of two contiguous chambers form together flues or passages for flame and
heated air from the fire, by which means such heated air is surrounded on
every side
the metal which is in contact with the water and steam contained
within the boiler; and I claim as of my Invention, such construction of steam

page_text: engine boilers as is herein described; and I do not claim as of my Invention
such part or parts of steam engine boilers, of furnaces, or of other things con-
nected therewith, in this description incidentally mentioned and adverted to for
the purpose of explication, as now are or may have been in common use.
In witness whereof, I have set my hand and seal, this Eighteenth day
of April, in the year of our Lord One thousand eight hundred and
thirty-three.
Inrolled the Eighteenth day of April, in the year of our Lord One
thousand eight hundred and thirty-three.