IMPROVEMENTS IN GENERATING STEAM AND EVAPORATING FLUIDS
Year: 1848

page_text: THESE
RESEN
SHALL COME, 1, JOHN
WRIGHT, of Camberwell, in the County of Surrey, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twelfth day of October, in
the twelfth year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said John Wright, my exors, adñiors, and assigns, Her especial
licence, full power, sole privilege and authority, that I, the said John Wright,
my exors, adñiors, and assigns, and such others as I, the said John Wright,
my exors, adors, or assigns, should at any time agree with, and no others,
from time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick upon Tweed, my Invention of "IMPROVEMENTS
IN GENERATING STEAM AND EVAPORATING FLUIDS;" in which said Letters Patent
is contained a proviso that I, the said John Wright, should cause a par-
ticular description of the nature of my said Invention, and in what manner
the same is to be performed, by an instrument in writing under my hand and
seal, to be inrolled in Her said Majesty's High Court of Chancery within
six calendar months next and immediately after the date of the said in part
recited Letters Patent, as in and by the same, reference being thereunto had,
will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
John Wright, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, are fully described and ascer
tained in and by the following statement thereof, reference being had to the
Drawings hereunto annexed, and to the figures, and letters marked thereon,
that is to say:-'
My Invention relates to the construction and application of tubes, and a
particular kind of cellular vessels charged with water or certain other fluids,
whereby heat may be transmitted from a fire or furnace to the interior of
steam boilers, or to tanks or other vessels, containing water or other liquids
intended to be boiled or evaporated. The system of evaporation to which my
Invention relates is that of circulation of a hot liquid through small tubes, or
one endless tube, as at Figure 1 of the Drawings hereunto annexed, where
heat being applied at a, the water in that portion of the tube is expanded, and
ascends by inferior gravity up through b, and thus puts the contents of the
entire coil in motion. The heated water, therefore, necessarily passes through
the vessel of cold water c, and gives out a portion of its heat; after which,
descending by superior gravity (arising from the contraction produced by the ab-
straction of the caloric taken up by the water in c) through d (being the lower leg
of the syphon) it returns to the fire a, and there takes up another charge of heat,
and thus every particle of the water successively becomes the recipient and
transmitter of caloric from the fire to the liquid to be boiled or evaporated.
And whereas in making use of this principle of evaporating liquids, it has
been customary to construct the tubes, passing through or among such fire and
liquids, of wrought iron tubes formed in several pieces, and joining them
together by screws or other mechanical joinings, depending on mere workman-
ship for their perfect union. Now in lieu of such arrangement, I propose to
construct of iron, gun metal, copper, or suitable alloys of copper, two or more
cellular vessels (and by a cellular vessel I mean a vessel consisting of several
hollow tubes or cells, formed in one piece, the general structure of which will
be understood by referring to Figures 2 and 3), which consist of a series of
transverse hollow tubes r, r, r, leading into longitudinal open-ended tubes b, b,
of larger area than the transverse tubes, and to place one or more such vessels
over the fire so as to be subjected to the action thereof, and to have one or
more immersed in and surrounded by the liquid intended to be boiled or
evaporated, connecting them by means of bent pipes and tight joints (con-
structed as shewn at Figure 11), so that the application of heat will produce
the required circulation of the enclosed fluid, and thus transmit the heat to the
liquid to be evaporated.

page_text: Where cast iron is the material of which my cellular vessels are constructed,
I propose in most cases to form them of the kind of metal employed to make
what is termed malleable cast iron, and when the castings are made (the trans-
verse cores through 7, r, being got out through a series of holes like d, d, d,
Figure 4, cast at the same time for that purpose in the outer longitudinal
tubes b, b, or one of them), the castings are subjected to the annealing or
converting process, whereby they are rendered perfectly ductile or malleable,
and are thus better adapted to sustain pressure or sudden and unequally
diffused changes of temperature than if left in the non-malleable state. The
holes d, d, d, are afterwards stopped by pins or screws, as generally known to
workmen.
And whereas in certain cases such as I have shewn, I propose to arch or
curve my cellular vessels, and for the convenience of moulding them accurately,
I propose generally to cast them flat, and after they are rendered malleable,
to bend them to the required curve, as shewn at g, h, i, Figure 10, and here-
after described.
And further, instead of casting the cellular vessels as described, I propose
in some cases to form them of corrugated wrought iron plates, which must be
first pressed, stamped, or rolled into the corrugated form represented by
Figure 5, which shews a corner of such a plate, and afterwards laying two
such plates together being previously heated to a welding heat, so that the
concavities of one are opposite to the concavities of the other; they are then
subjected to pressure between rolls or proper moulds and stamps, or a press,
and thus the two become united into one vessel, as shewn in section at
Figure 6. In some cases, however, instead of welding the corrugated plates
together, I propose to rivet them through the various surfaces in contact, as
will be readily seen at Figure 7, or it may occasionally be desirable to rivet the
welded plates in the same way also, for extra strength. It may sometimes be
convenient to construct the cellular vessels with the longitudinal tubes inclined
towards each other, as shewn at Figure 8. And as to construction:-Lastly, I
propose occasionally to form the cellular vessels so that although the interior
consists of longitudinal and transverse channels or cells, as already described,
the exterior consists of flat or plain surfaces, as shewn at Figure 4, which may
now be considered an end view of such a vessel. It is obvious also that the
cells or passages may be square or rectangular, instead of round in a vessel of
this description. These valves may be formed of the same material and bent
in the same way as those shewn at Figures 10 and 11.
Having now described the general rule which I intend to follow in con-
structing my cellular vessels, but which may evidently be varied to suit the

page_text: precise application, I shall now proceed to describe the mode of applying them
for generating steam or evaporating fluids according to my Invention.
and the fire.
Figure 10 represents an end view of a boiler for a steam engine in section,
to shew the internal application of my cellular vessels; and Figure 11 is a
longitudinal section thereof, supposed to be taken through a, a, Figure 10.
9, 9, is an arched cellular vessel, like Figure 2; it is placed between the boiler
i, (Figure. 10,) are two arched vessels (like Figure 3), placed
in the inside of the boiler and immersed in the water. The communication
between the cellular vessels in the inside and those on the outside of the
boiler is effected by having holes through the end plate (made steam and water
tight) and passing the horizontal ends j of bent tubes j, k, 1, (Figures 10
and 11) through such holes, and coupling them to the ends of the longitudinal
cellular tubes, in the way shewn at Figure 11, and which will be readily
understood by inspection of the Drawings.
It will be now apparent to an engineer how the circulation and transmission
of heat is carried on by my arrangement of cellular vessels. It is manifest.
that the heat of the fire first acting upon the cellular vessel g, g, and there-
fore causing the heated water contained therein to ascend through the pipe j
into the immersed cellular vessels at m and n (Figures 10 and 11), it circulates
through all the transverse tubes 7, 1, and the excess of heat in the circulating
water is at the same time given off to the water of the boiler from the surfaces
The insulated water in the vessels then descends through the tubes in
the direction of the arrows, and passing out at j, p, p, thence through the
bent pipes and 7, and so into the cellular vessel at 7, 7, where receiving
a fresh charge of heat, it again ascends through the pipe j, and so on con-
tinuously ad libitum.
of r, 1.
To follow or trace out the action of the fire, it will be seen that after it has
passed through the interstices of the lower cellular vessel g, g, (shewn by
arrows,) it impinges on the bottom of the boiler, and thence passing over the
bridge (s, s, Figure 11,) descends through the other interstices in g, g, and so
through the flues to the chimney in the ordinary way. This description of the
application of the cellular vessels, and the representation of its application to a
cylindric boiler, Figure 12, will furnish ample information as to how the system
may be varied to suit the particular kind of boiler or the particular kind of
evaporation it is proposed to apply it to. It will be clearly seen, that in
boiling or evaporating liquids it is necessary in all cases to place the cellular
vessel or vessels which receive the heat so as to be below the one or more which
give it out, and to immerse the upper cellular vessel or vessels in the fluid it
is to evaporate, or in some cases of open evaporation, where a large body of

page_text: liquid is not necessarily acted upon at once, the liquid may be thrown over the
upper cellular vessel or vessels in spray, or caused to flow over the heating
surfaces. It is necessary also to add, that to provide for the expansion of the
water; a branch pipe is carried from any convenient part of the descending
tubes at the back of the boiler, and having a small safety valve over the verti-
cal end of such branch loaded to the maximum pressure the cellular vessels
are intended to work at. There is also a small feed pump, similarly connected
to the tubes, for supplying any waste which may arise, and when the enclosed
water cools, the deficiency arising from contraction is self-supplied by passing
through the valves of the force pump just mentioned, all of which being gene-.
rally used in arrangements already practised on the principle of Figure 1, need
not be further described. In some cases I propose to form the sides of the
furnace of cellular vessels, in which case the transverse tubes will be vertical.
It is also manifest that where the depth of liquid will admit of it, the-im-
mersed cellular vessels may be placed with the transverse tubes vertical or nearly
so. These arrangements will be subject to the following modifications in the
boilers of locomotive or marine engines, or in other cases where it may be
necessary to have a large heating surface. In such cases the cellular vessels
will be of the form of 2, 2, Figure 13, and placed upright and parallel to cach
other, as will be seen by Figure 14, which shews at 3, 3, several such vessels
so arranged. It will there be seen that there are the same number of vessels
within the boiler as in the flue, and connected each with its opposite onc, so
as to allow a free flow of water from the one to the other at the joinings
4, 4. It will be seen, therefore, that the circulation is here carried on by each
pair of vessels independently of the other, and it is only necessary to add that
cach pair of vessels is kept charged by a pump common to all, and has a relief
valve like that already described; and, in short, the principle and mode of
action being precisely the same as that shewn in the land boiler (except as to
the position and general form) need not be further described. Figures 15 and
16 shew this form of application of my Invention adapted to marine boilers.
I further propose in some cases to have a series of one or more cellular vessels
placed above the level of the water in the boiler, in addition to the two series
or sets already described; and when such upper cellular vessel or vessels are
used, the injection or feed water is to be thrown over them by jets in the form
of spray, so as to facilitate the formation of steam in the boiler. And, lastly,
in lieu of water, as the heat transmitting fluid, I propose occasionally to charge
the cellular vessels with pure oils, coline or oleaginous matter, coal tar, or such
other fluids as boil only at a comparatively high temperature, or with such a
mercurial amalgam as does not solidify at the ordinary atmospheric temperature,

page_text: The object in using any of these matters being to avoid the internal pressure
water produces when heated above two hundred and twelve dégrees of
Fahrenheit.
Having thus described the nature of my said Invention, and the manner
of carrying the same into effect, I hereby declare that I lay no claim to the
principle of generating steam or evaporating fluids by circulation through tubes
generally, such having been known and practised long before the date of these
my Letters Patent; but what I claim is,―
First, the various cellular vessels, such as are shewn and described, when
the same are to be used to generate steam or evaporate liquids.
Second, the application for the purpose of generating steam or evaporating
liquids of cellular vessels, when the same are used according to the arrange-
ment comprehended in the preceding description, that is to say, more particu-
larly when one or more cellular vessels are immersed in the water or liquid to
be boiled or evaporated, and communicate with other vessels or tubes exposed
to the action of the fire.
In witness whereof, I, the said John Wright, have hereunto set my
hand and seal, this Eleventh day of April, in the year of our Lord
thod eight hundred and fonts