A CERTAIN IMPROVEMENT OR IMPROVEMENTS IN STEAM ENGINES AND STEAM BOILERS
Year: 1840

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
CRADDOCK, of Broadheath, near Prestigne, in the County of Radnor, Farmer,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent, under the Great Seal of Great Britain, bearing date at West-
minster, the Sixteenth of March, in the third year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said Thomas
Craddock, Her especial licence, full power, sole privilege and authority, that
I, the said Thomas Craddock, my exors, adññiors, and assigns, or such others as
I, the said Thomas Craddock, my exors, adññiors, 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 "A CERTAIN IMPROVEMENT OR IMPROVEMENTS IN STEAM ENGINES
AND STEAM BOILERS;" in which said Letters Patent is contained a proviso
that I, the said Thomas Craddock, should cause a particular description of the
nature of my Invention, and in what manner the same is to be performed, 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: T
NOW KNOW YE, that in compliance with the said proviso, I proceed
to describe the nature of my improvements, and the manner in which the same
are to be carried into effect. My improvements in steam engines consist, first,
in an improved mode of obtaining a rotary motion from the rectilinear and
reciprocating motion of the piston rod; and, secondly, in an improved method
of condensing the steam.
My improvements in steam boilers consist in an improved construction of
boiler, and in an improved method of regulating the generation of the steam.
These several improvements I now proceed to describe with reference to the
accompanying Drawings, observing that where the same object is represented in
different points of view, the same letters denote the same parts in each Figure.
Figures 1, 2, and 3, refer to my first improvement, videlicit, the converting a
reciprocating movement into a rotatory one. Figure 1 is a side elevation;
Figure 2 an end view; and Figure 3 a plan, a small portion of which is in
section. a is the piston rod, carrying two toothed racks b and c, the former
lying behind and on one side of the latter, and the two are connected by curved
pieces, top and bottom. The teeth of these two racks project in the same
direction, and the rack 6 engages with a series of teeth d, occupying nearly the
half of the circumference of a drum e, which is firmly keyed to the main shaft
f. The rack c engages a pinion 9 placed on a shaft h lying between the two
racks, and this pinion engages a series of teeth k, occupying nearly the
remaining portion of the circumference of the drum e. The teeth at each
extremity of each series d and k, are attached to springs m, m. Upon examin-
ing the Drawing it will be seen that in the position shewn, the rack c is acting
upon the drum through the medium of the pinion g, and that the rack 6 has no
action upon the drum, as the teeth upon which it acts are on the opposite side
of the drum; therefore, supposing the piston rod to be ascending, the drum will
revolve in the direction of the arrow. By the time that the piston has completed
its up stroke the pinion will be disengaged from the last of the series of teeth k,
and the rack 6 will be engaged with the first of the series of teeth d, and upon
the descent of the piston the rack 6 will continue the motion of the drum in
the same direction; n is a guide roller at the back of the rack c to maintain it
in a vertical position. My claim under this head of Invention is the mechanical
arrangement of the apparatus delineated and described, whether employed for
converting the rectilineal into the rotary motion, or the rotary motion into
rectilineal.
Figures 4 and 5 represent my condensing apparatus, Figure 4 being a longi-
tudinal section, and Figure 5 a transverse section of the same; a and b are two
c) lindrical chambers, connected together by the bar c, and supported on hollow

page_text: axes d, d, which revolve in bearings at e, e.
From the chamber a radiate a
number of hollow arms f, f, which are connected together by a series of hollow
rings g, g, and from the chamber 6 branches a similar set of hollow arms con-
nected with each other by the hollow rings h, h. The rings f, f, and h, h, are
connected by a series of pipes i, i, of small diameter, which may make any con-
venient number of turns backwards and forwards between the two sets of arms.
k is a pipe connecting the hollow axis of the chamber a with the eduction pas-
sage of the steam engine, and is a pipe proceeding from the axis of the cham-
ber 6 to the reservoir or hot well. In lieu of connecting the pipes k and 7 with
the hollow axes of the condenser by stuffing box joints, I employ the following
method:-To the end of each pipe is attached a flange, ground perfectly flat on
each side, and the end of each of the hollow axes is inserted in a collar m, m,
the flanges of which are likewise ground flat, and are kept in contact with the
flanges of the pipes k and 7 by curved bolts n, n, which have antifriction rollers
at their ends that run upon the back of the flanges of the pipes. To allow for
expansion and contraction and for wear of the face of the flanges, the sockets or
collars m, m, are not immoveably attached to the hollow axes, but are merely
prevented from turning round upon the axes by two pins in the axes, which
enter into longitudinal grooves in the sockets, leaving the socket free to move
endwise; the socket is made air-tight upon the axis d by means of oiled silk or
other flexible material being tied around them; o is a rigger fastened upon the
axis and put in motion by the engine. The operation of the apparatus will be
readily perceived: the steam upon quitting the working cylinders enters the
chamber a, and from thence passes into the assemblage of pipes composing the
condenser, and the condenser being caused to revolve with great rapidity, the
caloric of the steam is rapidly abstracted by the air, and the steam thereby con-
densed; and the water resulting from its condensation is conveyed by the pipel
to a close reservoir or hot well, from which it is transmitted to the boiler by
the feed pump. To the lower end of the eduction pipe is attached a close box
p containing a valve regulated by a float, which in the event of any condensa-
tion of steam in the pipe k, rises as the water accumulates in the box, and opens
the valve, and the water then is conveyed by the pipe q to the reservoir or hot
well.
Under this head of my Invention I claim the exclusive right of condensing
the steam or vapour of water or other liquids by causing it to pass into
metallic tubes of small diameter (or into metallic vessels of any other suitable
figure), which tubes or other metallic vessels are put into motion (either
relative or otherwise) either in air or water, independently of any motion of
the carriage, boat, or vessel, to which the condenser may be attached, by which

page_text: means the condensation of the steam or vapour is greatly accellerated. Figures 6
to 9 represent my improvements in steam boilers and in the means of regulating
the generation of steam. Figure 6 is a longitudinal section of the boiler;
Figure 7, a transverse section; and Figure 8, a horizontal section of the same.
a and b are two furnaces or fire boxes, the sides of which are composed of the
ranges of verticle tubes c, c, which communicate at bottom with the rectangular
and tubular frame d, and at top with the corresponding frame e; into the frame
d is inserted a horizontal row of smaller tubes f, f, which form the grate and
serve as fire bars; and into the frame e is inserted a row of horizontal tubes
9, 9, which form the top of the furnaces.
The fuel is supplied from above by hoppers h, h, and shoots i, i, and a commu-
nication is formed between the two furnaces by a flue k, which connects the two
shoots. The ash pit is formed by a tank which contains water, which is evaporated
by the heat thrown down from the furnaces, and the vapour thereof being con-
veyed by a pipe to a condenser becomes condensed, and thereby furnishes a
supply to replace any loss from leakage. The sides of the furnace are enclosed
by a casing composed of the vertical tubes m, m, the lower ends of which are
inserted in the tubular frame n, n; and the upper ends in a similar frame o, o,
and a horizontal range of tubes p, p, inserted in the frame o, o, forms the roof
to the boiler; and to prevent the radiation of heat, this casing should be
covered with wood or any other bad conductor of caloric. The space between
the furnace and the casing forms a hot air flue, which communicates with the
ash pit by apertures q, q, furnished with suitable yalves. From the casing the
heated air and volatile products of combustion are conducted by a branch tube
r, r, to a compartment enclosing the working cylinders s, s, and the cylinder t,
which works the blowing fan u, and from thence into the atmosphere by the
chimney. Attached to the blower is a casing containing a number of syphon-
shaped tubes v, of small diameter, the ends of which are inserted in the two
transverse tubes w and a, the former of which is connected with the eduction
pipe y of the working cylinders, and the latter is connected with a pipe either
leading to the condenser or open to the atmosphere. The current of air from
the blower sweeping over the tubes v abstracts a portion of the heat of the steam,
and thereby condenses it, and the air (elevated in temperature, is conveyed
along the blast pipe z, which communicates by apertures 1, 1, with the ash pits,
and by the rising pipe 2 with the communication flue k. The supply of fuel
is regulated by the fluted rollers 3, 3, which receive a rotary motion from the
cylinder which works the fan, and the fuel falling upon a vibrating plate 4,
which receives its motion from the shaft of one of the rollers, is distributed
equally over the fire in the furnace.
I should have before mentioned that the

page_text: whole of the tubes composing the fire boxes are completely filled with water,
but that the frame o, o, and the horizontal tubes p, p, in the casing are
occupied by steam, and that the frame d, d, is connected to the water chamber
n, n, by the pipes 5, 5, and with the steam chamber o, o, by the pipes 6, 6.
Having thus described the parts separately, I shall briefly describe their
conjoint action. My object in constructing the boiler with two furnaces com-
municating with each other, is to effect the consumption of the smoke by
charging the furnaces alternately with fuel, and causing the smoke from the
recent fuel to descend through the fuel in the other furnace, which is in a state
of vivid combustion. Let it be supposed that a coke fire has been lighted in
each furnace: then the communication 1 of the ash pit of the furnace a with
the blast pipe being opened, and the apertures q, q, which connect the same
ash pit with the hot air flue closed, whilst the communication of the ash pit of
the furnace 6 with the blast pipe is closed, and the communication with the
hot air flue is opened, the rollers which supply the furnace a with coal are set
in motion, and a quantity of coal is gradually distributed over the surface of
the ignited fuel. The smoke from this coal is carried along the communica-
tion flue k by the current of air rushing up from the ash pit, and mixed with a
portion of fresh air, which enters the communication flue k by the pipe 2,
and descending through the ignited coke in the furnace 6 is thereby consumed,
whilst the heated air and gaseous products of combustion pass out through the
ash pit of 6 into the hot air flue, and in the direction of the arrows to the
chimney. When the fuel in a is burnt bright, and that in brequires replenish-
ing, the ash pit of a is closed to the blast pipe and opened to the hot air flue;
and the ash pit of 6 is opened to the blast and closed to the air flue, at the same
time the feeding rollers of a are stopped and those of 6 set in motion. 7 is the
aperture, with a suitable cover, by which the fire is introduced; and to afford
the means of viewing the fire there is a tube 8 mounted on a swivel joint, and
furnished with an eye piece of talc. g is the ash pit door. For boilers which
are intended to consume coke only, I propose to employ one furnace only, from
which the heated air from gaseous products of combustion pass into the casing
by an opening in the roof the furnace, and then descending, pass into the com-
partment in which the cylinders are enclosed, from which they escape by
an aperture in the top.
The means by which I regulate the generation of steam consists in causing the
pressure of the steam in the boiler to regulate the supply of steam to the small
cylinder which drives the blowing and feeding apparatus, in such manner that
as the pressure increases the supply of steam to the small cylinder is diminished,

page_text: and its action thereby retarded, and consequently the supply of air and fuel
to the fire is diminished. Figure 9 shews a method of effecting this. a is a
cylinder connected with the steam boiler by a neck at b, and c is a cylinder of
smaller diameter cast in one with a, and concentrical with it. d is an aperture
in the cylinder a, which communicates with the condenser or with the atmo-
sphere; and e is an aperture in the cylinder c, which communicates with the
blowing cylinder. The cylinder a contains a piston f with a metallic packing,
which piston is connected by a rod to another piston g in the cylinder c, and
from the piston rises a stem h, upon which a steel yard spring k acts. So
long as the pressure of the steam does not exceed the regulated working pressure,
the spring maintains the piston at the bottom of their respective cylinders, in
which position the aperture which admits the steam to the blowing cylinder is
open, and the aperture d is closed; but as the pressure of the steam increases
the pistons rise, and the aperture e is first closed gradually, thereby the steam
is shut off from the blowing cylinder; and should the pressure continue to
increase, the aperture d is gradually opened, by which the steam is allowed to
escape into the atmosphere or condenser. m is an inverted syphon tube attached
by one leg to the cylinder a below the part to which the piston descends, and
having inserted in the other leg a glass tube hermetically sealed at top, attached
to which is a graduated scale. Under the head of improvements on boilers I claim
as my Invention, first, the general construction and arrangement of the parts
constituting the boiler shewn in the Figures 6, 7, and 8. Second, the employ-
ment of a separate cylinder to supply both air and fuel to the furnaces, and the
regulating the supply of steam to such cylinder by means of the pressure of
the steam in the boiler, in such manner that as such pressure increases the
supply of steam to the cylinder t is gradually diminished, thereby diminishing
the supply of air and fuel to the furnace. But I would observe that I do not
claim the separate cylinder for driving either the blower or the feeding apparatus
separately, but only when combined with each other, and with the mode of
regulating the supply of steam to the cylinder by the pressure of the steam in
the boiler.
In witness whereof, I, the said Thomas Craddock, have hereunto set my
hand and seal, this Sixteenth day of September, One thousand eight
hundred and forty.
THOMAS (L.S.) CRADDOCK.

page_text: AND BE IT REMEMBERED, that on the Sixteenth day of September,
in the year of our Lord 1840, the aforesaid Thomas Craddock came before our
said Lady the Queen in Her Chancery, and acknowledged the Indenture
aforesaid, and all and every thing therein contained and specified, in form above
written. And also the Indenture aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Inrolled the Sixteenth day of September, in the year of our Lord One
thousand eight hundred and forty.
Inrolled the Sixteenth day of September, in the year of our Lord One
thousand eight hundred and forty