CERTAIN IMPROVEMENTS ON STEAM ENGINES
Year: 1823

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
WIGSTON, of Derby, in the County of Derby, Engineer, send greeting.
WHEREAS His most Excellent Majesty King George the Fourth did,
by His Letters Patent under the Great Seal of that part of the United
Kingdom of Great Britain and Ireland called England, bearing date at
Westminster, the Eleventh day of August, One thousand eight hundred and
twenty-three, in the fourth year of His reign, give and grant unto me, my
exors, adiñiors, and assigns, His especial licence, full power, sole privilege
and authority, that I, the said William Wigston, my exors, adññiors, and
assigns, during the term of years therein mentioned, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of
Berwick-upon-Tweed, my Invention of "CERTAIN IMPROVEMENTS ON STEAM
ENGINES;" in which said Letters Patent there is contained a proviso that if
I, the said William Wigston, shall not particularly describe and ascertain 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, and cause the same
to be inrolled in His Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said Letters Patent, that
then the said Letters Patent and all liberties and advantages whatsoover
thereby granted, shall utterly cease, determine, and become void, as in and
by the same, relation being thereunto bad, will more fully and at large
appear.
NOW KNOW YE, that in compliance with the said proviso, I, the
said William Wigston, do hereby declare that the nature of my said Invention,

page_text: and the manner in which the same is to be performed, are particularly described
and ascertained in the following description thereof (that is to say):-
My Invention consists in the employment of one or more plungers or moving
weights composed of any ponderous material, which plungers or weights are
caused to rise and fall within suitable cylinders or cases (and thus operate by
their own weight or gravity for the purpose of actuating or giving motion to
any description of machinery) by the aid of stean, and through the medium or
intervention of a fluid metal, such as mercury, or any other metal or mixture of
metals which is capable of being retained in a fluid state by the application of
a moderate degree of heat, such as lead or tin, or an alloy composed of lead,
tin, and bismuth.
In order to render the nature and application of my said Invention clear
and intelligible, and to enable persons conversant with works of a similar
nature to put it in practice, I have hereunto aunexed a Sheet of Drawings
which will serve to explain two different modes of carrying my aforesaid
improvements into effect.
Fig. 1 represents an external view of the operative or working parts of
the engine or apparatus, supposed to be detached from the usual appendages
of working beam, connecting rod, crank, and fly wheel, which appendages
aforesaid are so well understood at the present period as to require no particular
description in this' Specification.
Fig. 2 upon the annexed Drawing represents a section of the same engine,
supposed to be taken through the middle in order to explain its internal
construction.
Fig. 3 shews an horizontal plan of the upper part of the engine; and
Fig. 4 shews another horizontal plan, wherein the lids or covers of the various
cylinders and boxes are supposed to be removed in order to facilitate the
explanation. This engine is furnished with two seperate weights or plungers,
which are adapted to be moved up and down, so as to operate in succession,
and thereby produce a continued action similar to an ordinary double-acting
steam engine. Note.-The Figures 1, 2, 3, and 4, are drawn to a scale of about
three fourths of an inch to a foot, and the same characters or letters are used
to deuote corresponding parts upon the Figures whenever they occur. A and B
represent two cylinders or cases of cast iron, which communicate freely with
cach other at their lower extremities in the manner of an inverted syphon, as
seen at c. The upper extremities of the cylinders A and B have flanges a, a,
formed upon them, which are bolted to the under side of an oblong box or
nossel piece C, D, by which means the upper ends of the two cylinders are
securely united together. The nossel piece C, D, has cavities or passages

page_text: formed in it, which are calculated for the admission and exit of steam to the
cylinders. These passages form a right angle or elbow in the said nossel piece,
and terminate in oblong slits or openings in the upper surface thereof, as
represented by the dark spaces in the plan, Fig. 4, where the opening marked 1
is shewn by the dotted passage 1 as communicating with the upper part of the
cylinder B, whilst the opening marked 2 is shewn by the dotted passage 2
as communicating with the upper part of the cylinder A, at the same time the
centre or middle opening marked 3 passes downwards through the nossel
piece C, D, and communicates by the pipe E directly with the atmosphere,
when the engine is intended to be worked high pressure, or by the elastic
force of the steam alone, otherwise the pipe E may serve as an eduction pipe to
communicate with the usual condensing apparatus, such as is generally
employed in steam engines. The openings 1, 2, and 3, before mentioned,
are covered by a small inverted box or sliding valve 5, such as is commonly
employed in steam engines, for the purpose of distributing the steam in the
cylinder. The sliding valve 5 is adapted to be moved by a rack engaging with
the teeth of a sector fixed upon a short spindle 6, passing through the side of
the steam box F, which box is of sufficient dimensions within side to admit of
the requisite sliding motion being given to the valve 5. The steam box is
bolted upon the upper surface of the nossel piece, and is furnished with a lid
or cover, secured by screw bolts upon its upper side for the convenience of
gaining access to the sliding valve and apparatus contained in the interior of
the said box. G represents the steam pipe, which serves to convey a continual
supply of steam from the boiler to the steam box F; it is furnished with its
throttle valve at S. HI and I represent two metallic weights or plungers, which
are of such dimensions as to leave about a half an inch space intirely round
within the cylinders A and B; at the same time the rings or projections h
and i, which are represented in the Figure 2, arc of such dimensions as to fit
the interior of the cylinders as near as may be, to admit of their sliding freely
up and down. The plungers H and I are each furnished with a cylindrical
rod K and L, similar to the piston rod of a steam engine, which is keyed or
otherwise securely fixed to the upper ends of the said plungers. The plunger
rods K and L pass through collars or stuffing boxes M and N, situated in the
centre of the lids or covers m and n of the cylinders A and B, as represented
in the Figure 2. The operation of this engine would be as follows:-Suppose
the plungers Hand I to be at rest in the position represented by the dotted
lines in the Figure 1, when they would balance each other and remain in
equilibrium; then suppose the lower part or connecting bend c of the
cylinders A and B, as well as the spaces round the plungers, to be filled to

page_text: about the level of the dotted line o, p, with any fit and suitable ponderous
metal, which, if required, is kept in a fluid state by the application of heat, as
aforesaid; in this situation we will suppose the steam box F to be supplied
with steam from the boiler, and the sliding valve 5 to be in such a position
that it would admit the steam to flow freely through the passage 2, before
mentioned, into the upper part of the cylinder A; at the same time the
sliding valve 5 would establish a communication through the passage 1 before
mentioned, between the upper part of the cylinder B and the exit or eduction
pipe E. In this situation the steam would descend by the sides of the
plunger H, and would operate upon the surface of the fluid metal to depress
it in the cylinder A, and thereby cause a corresponding rise of the fluid metal
in the cylinder B, which would pass up round the plunger I, and destroy the
equilibrium by leaving the plunger H unsupported by the fluid metal, and at
the same time (provided the fluid metal employed exceeded in specific gravity
the metal or substance of which the plungers was composed) it would float or
buoy up the plunger I in a certain degree; thus the plunger H would be
caused to descend in the cylinder A with a power or force equal to its own
weight or gravity, and the plunger I would be caused to ascend in the
cylinder B with a power or force equal to the difference of specific gravity
which might exist between the plungers and the fluid metal, until they assumed
the position shewn in Figure 2, at which instant the sliding valve 5, before
mentioned, would be moved (by its connection with the engine in the usual
manner) so as to reverse the order of communication between the steam
passages aforesaid, and thus admit the steam to flow from the steam box F
into the upper part of the cylinder B, and at the same time to establish a
communication between the upper part of the cylinder A and the exit or
eduction pipe E, and shewn by the small darts or arrows in Fig. 2. In this
state the steam would exert its elastic force upon the surface of the fluid metal
in the cylinder B, and cause it to descend and rise in the cylinder A, thereby
leaving the plunger I unsupported, and buoying up, as aforesaid, the plunger H,
by which means the plunger I would descend by its own gravity at the saine
time that the plunger H would ascend, the steam escaping from the upper
part of the cylinder A through the eduction pipe E, as before described. Thus,
a continued and powerful action may be kept up by the alternate ascent and
descent of the two plungers, which, by their two rods K and L being connected
either by racks upon the said rods working into the opposite circumference of
a toothed wheel, as represented by the dotted circle at P in Fig. 2, or by the
rods K and L being attached to seperate working beams furnished with con-
necting rods and crancks in the manner well known and practised in steam

page_text: engines. The motion of the said plunges might be communicated to any
description of machinery. Note.-If the eduction pipe E was connected with
the usual condensing apparatus as aforesaid, the engine would be capable of
performing its work with steam of a less degree of clastic force, since the
atmospheric pressure would always be removed from the surface of the fluid
metal in that cylinder in which it was in the act of rising.
Figure 5 upon the annexed Drawing will serve to explain an engine con-
structed according to my improvements, being adopted to operate with one
weight or plunger only, so as to produce the effect of a single acting steam
engine, such as are in general used for the pumping or raising of water. A, A,
represents the external cylinder or casing, which is formed with a close hemi-
sperical bottom at c, and is cast or otherwise securely connected with the
cylinder B, B. The interior cylinder is formed open at bottom so as to com-
municate freely with the annular space e, e, which is left between the two
cylinders. This annular space ought to be equal in its sectional area to the
area of the interior cylinder B, B. H reprosents the weight or plunger, which
is of such dimensions as to move easily up and down within the interior
cylinder, as before described with reference to the former engine. K represents
the plunger rod, which is securely fixed to the upper part of the plunger, and
slides through a collar or stuffing box M, formed in the centre of the cylinder
lid a, a. F represents the steam box containing the sliding valve 5 for distri-
buting the steam, being furnished with a rack and toothed sector, as seen in the
Fig. 5. G shews the steam pipe proceeding from the boiler to the steam box
F. The openings or steam passages over which the sliding valve 5 is placed
are clearly represented by the dark spaces in the plan, Fig. 6, where the
opening marked 1 is represented by the dotted passage 1 as communicating
with the upper part of the interior cylinder B, B, and the opening marked 2
communicates with the annular space e, c, between the two cylinders before
mentioned; this passage is seen more distinctly at 2 in Fig. 5, as also the
middle or centre passage 3, which communicates directly with the exit or
eduction pipe E, and condensing apparatus, if such should be employed, as
aforesaid. The operation of this engine would be as follows:-Suppose the
plunger H to be in the position represented by the Fig. 5, and the lower part
of the cylinders to be occupied by the fluid metal, the sliding valve 5 being in
such a position that the steam would have liberty to flow freely through the
passage 2 into the annular space e, e, at the same time that the upper part of
the interior cylinder B, B, had a free communication with the condensing
apparatus through the eduction pipe E, as herein-before mentioned, in this
situation the elastic force of the steam would operate to depress the surface of

page_text: the fluid metal in the annular space c, e, at the same time the atmospheric
pressure being removed from the surface of the fluid metal within the interior
cylinder B, B, it would be caused to descend in the annular space e, e, and
consequently to rise within the said cylinder until the weight of the column of
fluid metal became superior to the weight of the plunger E, in which case the
said plunger, with its rod K, would move upwards and carry one extremity of
the working beam of the engine along with it, so as to prepare the pump, which
is supposed to be situated at the opposite extremity of the said working beam,
for making an effective stroke. As soon as the plunger HI arrives at the top of
the cylinder B, B, the sliding valve 5 is moved in order to change the direction
of the steam passages, and thereby suffer the steam to flow freely from the
steam box F into the upper part of the cylinder B, B, at the same time that a
communication is established between the annular space e, e, and the condensing
appartus, in which situation the steam would press upon the surface of the
fluid metal in the cylinder B, B, at the same time the atmospheric pressure
being removed from the surface of the fluid metal in the annular space e, e, the
fluid metal would be caused to descend in the cylinder B, B, and rise within the
said annular space, thereby leaving the plunger E unsupported; it would neces-
sarily descend by its own gravity and carry the end of the working beam afore-
said along with it so as to produce an effective stroke of the pump and be
capable of raising a column of water weighing equal (upon the pump bucket)
to the weight of the plunger, thus a reciprocating movement of the plunger
may be kept up as long as a supply of steam is furnished by the boiler. The
means I prefer and have adopted for keeping the metal aforesaid in a fluid state
is by carrying a flue or passage round the lower part of the cylinder or cases
containing the said metal, which flue or passage is a continuation of the engine
boiler flues, so that any degree of heat which might pass off from the boiler
flue without being absorbed, is advantageously employed, but in some cases it
might be adviseable to employ a small seperate furnace for the aforesaid
surface.
I have been obliged to describe many parts in this Specification which have
been heretofore used and practised, and therefore can form no part of my
present Invention, such as the employment of fluid metals, such having been
heretofore used in some description of steam engines, as also sliding valves,
cylinders, and many other parts.
And I hereby declare that my said Invention consists solely in the employment
of moving weights or plungers contained in cylinders or cases partly filled with
any fluid metal as aforesaid, which said plungers or weights, after being raised
by the force of steam in the manner aforesaid, are caused to descend by their