AN IMPROVED STEAM ENGINE, WHICH MAY DE ALSO WORKED BY AIR AND OTHER FLUIDS
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, RICHARD
WANT and GEORGE VERNUM, both of Enfield, in the County of Middlesex,
Engineers, 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 Tenth day of
June, One thousand eight hundred and forty-eight, in the eleventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said Richard Want and George Vernum, our exors, adñors, and assigns,
Her especial licence, full power, sole privilege and authority, that we, the said
Richard Want and George Vernum, our exors, admors, and assigns, and such
others as we, the said Richard Want and George Vernum, our exors, aduiors,
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, and in the Islands of Guernsey, Jersey, Alderney, Sark,
and Man, and in all Her said Majesty's Colonies and Plantations abroad, our
Invention of "AN IMPROVED STEAM ENGINE, WHICH MAY DE ALSO WORKED BY AIR
AND OTHER FLUIDS;" in which said Letters Patent is contained a proviso that
we, the said Richard Want and George Vernum, or one of us, should cause a
particular description of the nature of our said Invention, and the manner in

page_text: which the same is to be performed, by an instrument in writing under our
hands and seals, or under the hand and seal of one of us, 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.
NOW KNOW YE, that in compliance with the said proviso, we, the said
Richard Want and George Vernum, hereby declare that the nature of the said
Invention, and in what manner the same is to be performed, are fully described
and ascertained in and by the present Specification thereof, reference being
had to the Drawings hereunto annexed, that is to say:-
Figure 1 is a front elevation of a double cylinder or non-condensing high-
pressure engine, constructed according to our Invention, and Figure 2 is a
side elevation of the same. A, A, is the framework; B, B, are two vertical
cylinders which oscillate on their bases, that is to say, on a hollow transverse
bearing or trunnion D, with which they communicate at bottom. B', B', are
the piston rods, which are attached at top to the crank shaft C, which is in a
line parallel with the under bearing D. The cranks are placed at right angles
to each other, so that the piston of one cylinder may be passing through the
most effective portion of its stroke, while the other is at its dead point. The
hollow transverse bearing D is divided into two sets of passages a, a, and b, b,
as represented in Figure 3, which is a horizontal section of it, on the line a, y,
of Figures 1 and 2, and in Figure 4, which is a plan of the same.
F is a
six-way cock, which occupies the centre of the bearing D, and through which
steam may be admitted from the pipe G (which communicates directly with
the boiler), into either of the sets of passages a, a, or b, b. The openings in
the plug are so arranged that when the passages a, a, are in communication
with the steam pipe G (as represented in the Drawing), then tho passages b, b,
communicate with the opening c in the plug of the cock F, which opening
leads directly to the exhaust pipo H.
Figure 5 is a vertical section on the line a, b, of Figure 3, shewing the pas-
sages for the steam through the plug F' of the cock F. All round the plug
there is a hollow groovo d, cut, which comes immediately opposite to the
opening of the steam pipe G, so that the steam has free access into that groove
at all times. From that groove the steam passes into a chamber c, formed in
the upper part of the plug, from which chamber it flows through the openings
ff, into the passages a, a. By referring to the horizontal section Figure 3,
of the trunnion D, it will be seen that when the two passages f,f, of the cock
coincide with the passages a, a, of the trunnion D, then two of the other four

page_text: passages or openings g, g, y, g, which are in the plug F', must coincide with
the two passages b, b, of the trunnion, and allow the steam to escape from the
cylinders into the exhaust pipe H. Each of the passages a, a, terminates et
the end of the trunnion D in a bend, so that it may communicate with the
two outside ports h, h, while the other passages b, b, terminate in the mid ports
i, i, which are placed directly beneath the lower ends of the cylinders A, A,
with the steam port facings of which they exactly correspond.
In Figure 6, which is a vertical section of one of the cylinders, and the parts
immediately belonging to it, the cylinder and piston rod are represented in the
position which they would occupy at the commencemont of the stroke of the
piston.
In Figure 7, which is another vertical section of the same parts, the cylinder
and piston are represented as at half stroke, and the ports and passages in such
relative positions that the steam shall pass in beneath the piston from the left-
hand side of the passage a of the trunnion, through the port k, while at the
same time the exhaust passage b is open for the escape of steam from above
the piston by the steam passage or port 1. At the termination of the stroke,
the ports become entirely closed to each other, as represented in Figure 6.
The moment, however, the crank passes the centre, the cylinder becomes
inclined to the opposite side, and tho right-hand side of the passage a is then
opened for the admission of steam to the top of the cylinder, while the bottom
of the cylinder is thrown open to the exhaust pipe, and thus the working of the
engine goes on continuously.
A great advantage gained by having the trunnion at the bottom of the
cylinder instead of at the centre, as in oscillating engines generally, is that the
piston rod makes a much less angle with the crank shaft, and thereby throws
less strain upon the framing, and is consequently productive of much less
friction. Again, the relative positions of the ports and steam passages afford
greater facility in reversing the engine, because the moment the cock Fis
turned round, so as to bring the openings f, f, opposite to the passages b, b, in the
trunnion D, then the passages g, g, are in connection with the passages", ",
which renders the latter for the time exhaust passages, while the others b, b,
become steam passages, which at once completes the arrangement for reversing
the motion of the engine. The port facings upon the bottoms of the cylinders
are kept in contact with those in the trunnion by means of the glands H³, H³,
which, together with the cylinders, are truly bored out so as to fit the trunnion.
When any slackness arises from wear, this defect can easily be rectified, by
screwing up the bolts connecting the glands to the cylinders.
Figure 8 is a front elevation of a single-cylinder condensing engine, con-

page_text: structed according to our said Invention; and Figure 9 is a side elevation of
the same. A, A, is the framing. B, the cylinder: C, the hollow trunnion
upon which the cylinder oscillates. D, the steam supply pipe. F, the exhaust
pipe. E, a cock which opens and closes the induction and eduction passages,
and is of a similar construction to the six-way cock before described; the only.
difference being that, as there is but one cylinder to this condensing engine, so
there is but one half the number of ways required in the cocks is the con-
denser. His the air pump which communicates with the condenser through
a three-way cock I, exactly like the steam cock E. The air pump also is
nearly in every respect-constructed in the same way as the steam cylinder B;
oscillating at its base upon a hollow trunnion F³, the passages in which serve-
all the purposes of the valves ordinarily used.
A double cylinder condensing engine may be also built on the same plan;.
but the modifications and additions réquisite for that purpose must be so
obvious to all persons conversant with the steam engine, that any separate
description of them would be superfluous.
Figure 1 is a sectional clevation of a cylinder with ports and steam'
passages similar to those of the engines which we have already described, but
differing from it in being centred upon two bearings A. A, (only one of which
is seen in the Drawing,) which are cast upon or affixed to the sides of the
cylinder. B is a block which is attached to the bottom of the cylinder,' and'
fits into the top of an upright chest C, 'in which there are passages similar to
those in the hollow trunnion represented in Fig. 3. The bearing surfaces of
the block B, and the top of the case.C, are portions of a circle struck from
the centre of the bearings A.
Figures 10 and 11-show how our Invention may be applied to locomotive
engines, the former being an elevation, and the latter a plan of a locomotive
with engines on our plan. In this case, however, we propose to employ two
pairs of cylinders, cach pair consisting of two cylinders, connected end to end.
together, and the two pairs, being centred on the opposite ends of a transverse
hollow trunnion on which they oscillate, as also two air pumps, one to each:
pair of engines. An arrangement of this sort is more especially applicable to
heavy locomotives, as in such case the weight of the one set of cylinders would
act as a counterpoise to the opposite set, and thus throw the whole weight of
the cylinders upon the trunnion, leaving the crank pins and piston rods entirely
free from the load which is generally thrown upon those parts by oscillating
engines of the ordinary description (where such are used). A, A, is the frame-
work of the carriage. B, B, and B', B', are the two pairs of steam cylinders.
C, C, and C, C, are the pistoii rods (each cylinder being provided with a
S

page_text: separate piston rod), which are directly connected to the four driving. wheels
of the carriage by the crank pins D, D, D', D¹. The connections between
the piston rods and the crank pins are formed by ball and socket joints, so that
the oscillations of the carriage may be thereby prevented from injuriously
affecting the piston rods or cylinders. E is the trunnion upon which the pairs
of cylinders are centred, and through which the steam is admitted and dis-
charged, being in this respect exactly the same as the trunnion of the non-
condensing engines first herein-before described, save that it has double the
number of ports entering into the steam passages a and b, as represented in
Figure 12, which is a cross section of the trunnion now in course of description,
and the ports of the cylinders immediately in connection with it (the occasion
for this double number of ports arises from the application of the additional
cylinders). For the efficient working of engines in this locomotive application
of them it will obviously be necessary that in connecting the two cylinders
together of which each pair consists, their centre or axial lines should be in
the same straight line, and that the bearing F, F, for the trunnion should be
bored out at right angles to the same line. In the Drawings (Figure 12), the
bearing F, F, is represented as being formed out of projections on the bottoms
of the cylinders, and cast in one piece with them; but the cylinders and the
bearings may, if preferred, be cast separately, and afterwards connected by
bolts and nuts. Should the wearing of either the trunnion or the bearings
upon the cylinder bottoms render these parts leaky, this may be readily
remedied by screwing up the bolts connecting the flanges of the two sides of
the bearings F, F. When these bearings are bored out in the first instance,
we leave a space between them at f, f, by the insertion of a plate of metal or
some hard substance, so that we may have it subsequently in our power to
rectify any defect by the wearing of those parts, by inserting a thinner plate of
metal in the place of that originally used. When the bearings of the axles of
the wheels of the locomotive are rigidly affixed to the frame of the carriage,
then the cylinder trunnion must be also securely affixed to the framework; but
as the bearings of the wheel axles are generally allowed some latitude of play
up and down in the framework to which they are attached, through the medium
of springs, it will also in such case be necessary to give the trunnion and
cylinders a corresponding play vertically, because if any of the wheels should
5. be raised up from any unevenness of the rails or occasional obstruction, the
raising of the wheel would be apt to bend or break the piston rod. We
therefore allow the trunnion F to have such a degree of vertical play as may
suffice to prevent such accident, and this we accomplish by placing the trunnion
in slotted bearings G, G, which are attached to the framework (as shewn in

page_text: Figure 10). These slotted bearings are provided with helical springs above
and below the trunnion to prevent its working up and down, except when it
may be necessary for it to do so. The steam pipe connecting the boiler with
the trunnion F is provided with a packed telescope joint, which admits of the
pipe lengthening or shortening, according as the trunnion is removed further
from or nearer to the boiler by the vertical play which is allowed to it in the
bearings G, G. II is the exhaust pipe. I, a six-way cock, similar to that
before described, for reversing the motion of the engines, or for shutting off
the steam altogether from the cylinders. K is a feed pump for supplying
water to the boiler, and which is similar both in form and in action to the air
pump and steam cylinders both herein-before described. L is the trunnion
upon which K oscillates; and M, a three-way cock, by which the driver directs
the course of the water through the trunnion, according as the engine may be
going forward or backward. This three-way cock is exactly of the same
construction as the six-way steam cock, and it has but three ways, because
there is only one feed pump supposed to be employed; but when two forco
pumps are used, then the three-way cock must be changed for a six-way one.
A light class of locomotive engines may be constructed with one pair of single
cylinders one cylinder on each side. Or again, instead of having a second
cylinder upon the opposite side of the trunnion, a single cylinder at one end
only may be used, with a weight at the other end to counterbalance it. In
locomotive engines of this sort, the hollow trunnion of the cylinders should
always be permanently and securely fixed to the framework, as it is not
necessary that it should yield along with the side bearing of the wheel to which
the piston rod is attached. In the preceding description we have supposed the
engine to be worked by steam, but it will be obvious that it may be also
worked by air and other fluids.
And having now described the nature of our said Invention, and in what
manner the saine is to be performed, we declare that what we claim is, the
improved engine before described, in so far as regards the manner in which
the cylinders are centred on and communicate with the hollow trunnion, and
the mode in which the said trunnion is internally constructed, and whether the
said engine is actuated by steam, air, or any other fluid.
In witness whereof, we, the said Richard Want and George Vernum,
have hereunto set our hands and seals, this Eighth day of December,
in the year of our Lord One thousand eight hundred and forty-eight.
RICHARD (L.S.) WANT. GEORGE (L.s.) VERNUM.

page_text: AND BE IT REMEMBERED, that on the Eighth day of December, in
the year of our Lord 1848, the aforesaid Richard Want and George Vernum
came before our said Lady the Queen in Her Chancery, and acknowledged
tlic 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 Statute made for that purpose.
Enrolled the Ninth day of December, in the year of our Lord One
thousand eight hundred and forty-eight.