AN IMPROVEMENT IN THE CONSTRUCTION OF ROTATORY STEAM ENGINES
Year: 1846

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
SEYMOUR WESTMACOTT, of Number 28, John Street, Bedford Row, in the
County of Middlesex, Gentleman, send greeting
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent under the Great Seal of the United Kingdom of Great Britain and
Ireland, bearing date at Westminster, the Thirtieth day of May, in the ninth
year of Her reign, did give and grant unto me, my exors, adiñors, and assigns,
Her especial licence, full power, sole privilege and authority, that I, the said
Henry Seymour Westmacott, my exors, adiñois, and assigns, and such others as
I, the said Henry Seymour Westmacott, my exois, adññiois, and assigns, should
at any time agree with, and no others, from time to time and at all times
thereafter during the term of years thei ein mentioned, should and lawfully might
make, use, exercise, and vend, within that part of the United Kingdom of
Great Butain and Ireland called England, the Dominion of Wales, the
Town of Berwick-upon-Tweed, and all le said Majesty's Colonies and
Plantations abroad, the Invention of "AN IMPROVEMENT IN THE CONSTRUCTION
OF ROTATORY STEAM ENGINES;" in which said Letters Patent there is, amongst
others, contained a proviso that if I, the said Henry Seymour Westmacott,
should not particularly describe and ascertain the nature of the said Invention,
and in what manner the same is to be performed, by an instrument in writing,

page_text: unler my hand and seal, and cause the same to be enrolled in Her said
Majesty's High Court of Chancery within six calendar months next and
immediately after the date of the said recited Letters Patent, that then the
said Letters Patent, and all liberties and advantages whatsoever thereby
granted, should utterly cease, determine, and become void, as by the said
Letters Patent, reference being thereunto had, will more fully and at large
appear
NOW KNOW YE, that in compliance with the said recited proviso, I,
the said Henry Seymour Westmacott, do hereby declare the nature of the
Invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by these presents, and the Diawings therein
referred to and hereunto annexed.
In the annexed Drawing the same pieces in the several Figures are every-
where represented by the same letters; and, to understand the description the
better, Figures 1, 2, 3, and 4, present the engine moving forwards, and Figure 5,
on the contrary, shows the engine moving as well for wards as backwards
Figure 1 shows a vertical profile of the engine, and Figure 2 a horizontal one,
whereas Figure 3 shows the outward engine seen from the same side as Figure 1,
and Figure 4 shows the outward engine viewed on the outside of the cylinder.
The engine consists of two principal parts, namely, the fixed cylinder B, with the
pipes k, k, and the pieces m, m, and the moveable wheel A, with the four moveable
plates 1, 2, 2, 2, the valve spaces 9, 9, 9, 9, and the axle ć, the steam passage a, a, a, a.
and the holos o, o The steam passage, or the space in which the steam
operates to work the engine, is marked here with a [which replaces the steam
tube by the general steam engine] The stean passage a is bounded on the
one side by the cylinder B, and on the remaining three sides by the wheel A,
whose outward circumference is found so that the steam passage lies cut in
between the wheels' projecting side-edges t, t, (as shown in Figures 2 and 3),
which closes compact to the interior side of the cylinder B The plates 2, i, 1, 1,
can (as in Figure 2) be pushed down in the valve spaces 9, 9, 9, 9, and are
then out of the steam passage a, or they can be pushed up in the same (as
seen in the position 2, 1, in Figure 1), and thus, being in contact with the
interior surface of the cylinder B, they totally close the steam passage a The
pieces m m, which are screwed to the cylinder B, are formed so that, although
then outward edge quite closes the steam passage a, the wheel is not thereby
prevented from moving The ends of the plates 2, 2, 2, 2, are brought into the
edges t, t, of the wheel A (see Figure 2), and get thereby a more fixed
position, making the movement quite regular. The steam on entering from
the boiler by the pipes k, k, is prevented by the pieces m, m, from going in

page_text: then duection, and must consequently go forwards, but here it is stopped by
the plates i, i, which close the steam passage a, and prevent at the same time
the escape of the steam. The plates 2, i, sustain on one side the full pressure
of the steam, and as on the other side they have no equal or countervailing
pressure, the holes o, o, being open and in connection either with the condenser
or with the atmosphere, the pressure of the steam on the plates i, 2, will cause
the wheel A to revolve. The pieces m, m, are formed so that in closing the
passage a by means of the pipes k, h, they finish on the opposite side in a
regular diminishing wedge, which at last in the extreme point imperceptibly
closes with the surface of the inner cylinder. When the plates 1, i, moving
with the wheel, approach the pieces m, m, they slide gradually up the wedge
and enter by these means into the valve spaces g, g, till they have passed m, m,
when they are pressed by springs towards the surface of the inner cylinder and
close again the steam passage a. In this way the steam passage is always
closed by the two opposite plates i, 1, while the two others slide up the wedge
m, m, and the wheel is thus kept continually moving round in one direction
In Figure 5, the engine is represented capable of moving forwards and back-
wards; the pieces m, m, being formed in a wedge on both sides, and the steam
can be admitted on one or the other through the pipes k, k, or o, o For
instance, if the slider r is in the position represented by the Drawing, the
pipes o, o, are in connection with the condenser, or the external air through
the pipes, while, on the contrary, the pipes k, k, are in connection with the
steam pipe d, and the engine moves forward. If the slider r is pushed to the
opposite end, then the pipes k, k, are in connection with the condenser or
the external air, and the pipes o, o, with the steam pipe d, and the engine
moves backwards
The rotatory steam engine above described may be made of iron or brass,
or partly of one and partly of the other metal, as may be found convenient,
and steam of suitable pressure supplied from any boiler adapted to that purpose,
as is well understood by persons accustomed to steam engines And I wish it to
be understood, that what I claim as the Invention intended to be secured by
the said Letters Patent, is a rotatory steam engine, constructed and airanged
as above described
In witness whereof, I, the said Henry Seymour Westmacott, do hereunto
set my hand and seal, the Thirtieth day of November, in the year of
our Lord One thousand eight hundred and forty-six.
H. S. WESTMACOTT. (L.S.)

page_text: AND BE IT REMEMBERED, that on the Thirtieth day of November, in
the year of our Lord 1846, the aforesaid Henry Seymour Westmacott came
before our said Lady the Queen in Her 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 Statute made for that purpose
Enrolled the Thirtieth day of November, in the year of our Lord One
thousand eight hundred and forty-six.