CERTAIN IMPROVEMENTS IN STEAM CARRIAGES, WHICH IMPROVE- MENTS ARE APPLICABLE TO OTHER PURPOSES
Year: 1833

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
REDMUND, of Charles Street, City Road, in the Parish of Saint Luke, 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 the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-eighth day of
October, in the fourth year of His reign, did give and grant unto me, the
said David Redmund, my exors, adñiors, and assigns, His special licence,
that I, the said David Redmund, my exors, adññiors, and assigns, during the
term of years therein specified, should and lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick-upon-Tweed,
my Invention of "CERTAIN IMPROVEMENTS IN STEAM CARRIAGES, WHICH IMPROVE-
MENTS ARE APPLICABLE TO OTHER PURPOSES;" 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 thereunto 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 furnace, steam boiler,
and. wheels, adapted more especially to carriages to be impelled by the force of

page_text: steam, but which are also applicable, with advantage, in other forms and uses
of steam engines and carriages.
The following description, illustrated by the annexed Drawings, shews the
construction of my several improvements, and the mode in which the same
may be practised :-
The improvements which I have had in view in the contrivance of my
furnace for steam boilers, are, that a constant current of air should pass
generally through the whole mass of burning fuel; that a stream of cold air
should be made to flow unintermittingly, through the hollow metal supporters
of the fuel, in order, by keeping down the temperature of those parts of the
furnace, to retard their destruction in the fire; and further, that the fire bars,
by their form, should be less liable to fusion, and should have a tendency to
prevent choking by clinkers or ashes, so that the supply of air, for the mainte-
nance of combustion, may not be impeded. To accomplish these objects it is
necessary that a current of air should be impelled into the furnace and its
passages, either by a revolving fanner, by bellows, or by some other mechanical
forcer. The stream of air, which I have found to be effective, has been from
a fanner about two feet two inches in diameter, and one foot wide, making
eleven or twelve revolutions for one of the crank. I construct the floor of my
furnace in the following manner:-I make a rectangular hollow frame of cast
iron, the outer sides of which are square with the top and bottom, the inner
sides have a slope inwards from the lower margin to the upper. On the upper
surface of the frame are cast an angular fillet as a foot stop to the fire bricks,
and a sloping band or ledge, to which to bolt the casing of the walls. On one
of the exterior sides is an opening running nearly the whole length, with a
deep projecting margin for the purpose of receiving the air trunk from the
fanner or bellows, the cavity of this side of the frame, which may be called the
entrance chamber, is cut off at the ends by partitions from the general cavity
of the three other hollow sides. The inner plate of this same side of the frame
is perforated with as many openings as there are hollow fire bars, and the
inner plate of the side opposite is in like manner perforated so that the open-
ings in the two faces exactly correspond. When the hollow fire bars are in
their places within the frame the passages through them coincide with the
apertures of the two inner opposite plates of the frame, and form enclosed
air channels from the entrance chamber to the cavity of the opposite
side, traversing the area inclosed by the frame. By this arrangement
a stream of air forced into the entrance chamber will flow through the
hollow fire bars, and so much of it as does not pass through the holes
pierced in their upper sides, for the maintenance of combustion, will go

page_text: onwards into the cavity of the three other sides of the frame, and will eventually
escape through the vents at the two extremities of the cavity on the same side
of the frame in which the entrance chamber is situated. As the area of the
air vents may be more or less contracted in proportion to the volume of air
driven into the passages of the furnace floor, so will be the greater or smaller
force with which a portion of the air is impelled through the air holes of the
fire bars to act upon the fuel. The adjustment of the area of the air vents to
the volume of air driven in may be obtained by valves or dampers, allowing of
occasional closure to free the air holes of the fire bars from ashes, but in working
the current of cold air must be allowed to flow constantly through the cavities
of the fire floor, as on the cooling action of the air depends the longer duration
of the metal. The general form of the fire bars is that of a hollow pentagonal
prism, bevilled at it two ends to conform with the sloping faces of the internal
sides of the frames, and the bars are of such a length as to stretch from side to
side, so as to apply their ends exactly to cover the opposite openings cast in the
front and back sloping sides of the frame. The whole number of fire bars fills
the area enclosed by the frame, allowing only so much play as is required by the
expansion of the heated metal. They are supported in their places by flat bearing
bars held to the bottom of the frame by screws at each end. The transverse sec-
tion of a fire bar presents a pentagon, the two upper sides of which incline to
each other at a much more acute angle than do any two of the other sides. The
advantages of this form are, that on the fire surface of the furnace floor there
is no borizontal face to give a lodgment to the ashes or to facilitate the agglu-
tination of clinkers, both of which will therefore tend to fall through the spaces
betwixt the bars. The air holes are perforations in the two upper surfaces
of the bar at right angles to the faces, and from their inclined direction they
are less exposed to become choked by ashes or clinkers. By the broken
surface of the furnace floor made by these salient angles of the fire bars the
place of greatest intensity of heat is somewhat farther removed from the
grating, and consequently the bars will not so soon injure by the action of
the fire. This angular form of the bar, too, prevents a greater extent of
cooling surface under the influence of the incoming current of air, and it also
offers a larger mass of metal in proportion to the superincumbent fuel, and in
so much lessens the liability to fusion. In order not to present any thin edge
of metal to the great heat of the furnace, I prefer to round down the upper
angle of the fire bar. To force the driven stream of air upwards through the
fuel, it is necessary that the bottom of the furnace should be closed, which is
done by a flat plate screwed to the under side of the frame. The up-turned
margin of this plate is notched, to admit the flat bearing bars screwed on

page_text: before it, and other flat bars filling up the interspaces of the former, which can
be drawn out separately when the whole is fitted together. Under these
latter sliding bars there are rows of holes in the bottom plate at equal
distances, and the bars have similar holes at like distances, but so placed that
when the bars are pushed home the two sets of holes do not coincide. On
drawing out a bar to a certain distance the holes in the bar and the plate
correspond to allow the ashes to escape, and when the sliding bar is drawn
quite out a bent iron to stroke or rake the fire bars can be introduced, and the
ashes and small clinkers removed from betwixt the fire bars. A space is
preserved betwixt the contiguous fire bars for the fall of ashes by small butting
pieces cast on the ends. This space should be only about 3/8 inch wide, as
when anttracite or stone coals is the fuel employed it breaks down into small
particles, and much of it would pass through the fire unconsumed if the grate
were too open. I make the walls of my furnace of fire bricks, supported
externally by a casing of iron plate screwed or bolted to the projecting ledge
on the flooring frame. The fire bricks rest with their lower edges on the
flooring frame betwixt the fillets cast thereon, and are secured to the casing
by bolts.
Suitable doors are provided in the side walls for feeding and
drawing the fire. A stoppered opening is also sometimes made opposite to
the upper edges of the fire bars for the purpose of removing clinkers. I
claim as part of my present Invention the furnace as herein described.
The Drawings on Sheet I shew plans, views, and sections of the furnace and of
its several parts. Figure 1, horizontal section of the hollow flooring frame, with
the under bearing bars on which the fire bars rest. Figure II., the same, with
section of some of the fire bars in their places and some of the bearing bars
and perforated sliders. Figure III., plan of the upper surface of the furnace
floor, end view, and cross section of the same side, and end view and cross
section of a fire bar. IV., the perforated bottom plate and sliders.
V., front view of the furnace. Figure VI., longitudinal section.
Figure
Whereas I have made some improvement in the boiler formerly invented by
me, and described and claimed in the Specification inrolled in His Majesty's High
Court of Chancery, pursuant to a proviso contained in Letters Patent granted
to me, bearing date at Westminster, the Eighteenth day of October, in the
third year of the reign of His Majesty King William the Fourth, I now
proceed to describe such improvement. In my said former Specification I
described my boiler to consist of separate chambers, the sides of which were
formed of copper or other metal plates bent up into a series of nearly semi-
cylindrical flutings or arches, which corresponding when in place with the
similar arches of contiguous chambers former the fire flues and became the

page_text: principal heating surfaces of the boiler. The arches or fluted sides of the
chambers were described to be affixed by rivets to bottom and top pieces made
of cast copper or other metal. Since that Specification was enrolled I have
found that I can most advantageously make the top and bottom pieces as
therein described of malleable cast iron, which enables me to employ rolled
sheet iron for the sides of my chambers, whereby I obtain greater stiffness and
tenacity. The process by which I produce the requisite malleability in my
cast iron for the above purposes is this: I use what in England is known
under the name of Lorn pig iron, of which I melt together equal parts of grey
and white for my castings. The pieces so cast I then inclose in iron boxes,
in which they are imbedded in slightly calcined and pulverised red hæmatite
iron ore, and the whole is subjected in a close furnace to nearly a white
heat for about one hundred and thirty hours. The furnace is then allowed
to cool, and the cast iron when taken out is found to have acquired very
considerable malleability, admitting very perfectly of being rivetted, bent,
or caulked, so that I can make a very sound joint by rivetting and caulking
betwixt the sides and top and bottom pieces of my boiler chambers. The appli-
cation of cast iron prepared by the process above described, so as to become
malleable in the construction of the chambers of my before recited patent steam
boiler, I now claim as a part of my Invention, the exclusive right to which is
secured to me and to my legal representatives for a term by the Letters
Patent of which the present is the Specification. The tubes, connecting pieces,
and other cast parts of my boiler I find it preferable to make of the same
malleable metal, that all the connected parts may as nearly as possible
follow the same law of expansion and contraction by change of temperature.
To obtain a wheel, at the same time light, sightly, and strong for steam coaches
and other heavy carriages, I construct mine for the most part of malleable cast
iron, prepared as above described. For the Lorn pig above mentioned I some-
times substitute what is called "refined or forge iron (in the state of preparation
to which it is brought previously to puddling or tilting"). This iron when casu
I subject, under the circumstances before described, to a bright red or the
ordinary annealing heat for about eighty-four hours, when it will be found
sufficiently tough and malleable. I cast the nave of my wheel hollow to admit
the axletree box and to form a cavity for oil, with a fixed flange in the outer
5 surface of which are as many semi-cylindrical cavities as there are to be
spokes. A corresponding loose flange, with the same number of hollows on its
inner face, with a circular central aperture, fits over the boss of the nave, and
when bolted to the face of the fixed flange, completes the cylindrical sockets
for the central ends of the spokes. These sockets may be cleaned out by a

page_text: half round bit. For steam carriages the inner end of the nave is prolonged to
admit a chain, wheel, or other driving gear to be keyed upon it; an axletree box
of the ordinary kind is driven tight into the central aperture of the nave, and
provision made by small perforations in the bex to admit the oil from the oil
chamber to pass to the rubbing surfaces. The spokes of my wheels are hollow
cast from the Lorn pig iron, and converted to the malleable state. The general
form of the shaft of the spoke may be conical or cylindrical, but when less
strength is necessary, I form them, as the hollow shaft has been slit through
a portion of its length, and each half curved outwards, either as shewn in
the Drawing (Sheet 3) or into other more varied and fanciful curves. By
this construction I give an ornamental character to the wheel, and obtain a
little elasticity to break the concussions to the machinery from inequalities or
obstructions on the road. The spokes near their outward extremities have a
shoulder, beyond which they are turned cylindrical on the outside and tapped
within. The felloes are cast in segments, and in correspondence with each
spoke there is a boss which is bored true to receive the end of it, and comes
down upon the shoulder of the spoke. In putting on the felloes, a pin or bolt
at the heading joints holds them in their places until the rim or inner tire comes
on, which, being shrunk upon the felloes, holds all firmly together. This rim
tire must be bored opposite the hollow ends of each spoke, and the holes
countersunk to admit the screws which connect more firmly the spokes,
felloes, and inner tire. The outer or wearing tire I put on in segments, and
fix in its place by bolts passed through the felloes and both tires, and drawn
down by nuts on their inner ends. A space of about half an inch should be
left at each heading joint of the outer tire to allow of the extension of the
metal under wear. When the outer tire is worn down it may be readily
replaced. When the ornamental or split spokes are used, a tube with a cap
or plug may be inserted in one of them to convey oil to the oil chamber in the
nave, otherwise a screw hole may be made into the chamber in any convenient
situation. To prevent the spokes turning in their sockets in the nave, it is
adviseable to fix them by steady pins through one of the flanges; they may or
may not be filleted within the socket, as shewn. Under the present Patent I
claim the construction of the wheels as above described to be part of my
Invention.
The Drawings on Sheet 2 shew the construction of the several parts of my
wheel. Figure 1, section of nave, axle box, and cap, spokes, felloes, and tire.
Figure II., longitudinal section of felloes. Figure III., side view of felloes
and tire. Figure IV., heading joint of felloes.
felloes.
Figure V., cross section of

page_text: Sheet 3, the principal Drawing, is a side view of the wheel with open spokes,
the smaller ones shew the inner faces of the flanges.
I do not claim such parts in this Specification described as may have been
heretofore in common use, except in so far as they enter into the peculiar
arrangement and combination belonging to my present Inventions herein set
forth.
AND BE IT REMEMBERED, that on the Twenty-eighth day of April, in
the year of our Lord 1834, the aforesaid David Redmund came before our
said Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statutes made for that purpose.
Inrolled the Twenty-eighth day of April, in the year of our Lord One
thousand eight hundred and thirty-four.