CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF STEAM ENGINES
Year: 1798

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GREGORIO
FRANCISCO QUEIROZ, of Walham Green, in the County of Middlesex, Gentle-
man, send greeting.
WHEREAS His most Excellent Majesty King George the Third, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the. Twenty-ninth day of August, in the thirty-eighth year of His
reign, did give and grant unto Francisco Rapozo, of Lisbon, in the Kingdom
of Portugal, Captain of Engineers, in the service of Her most Faithful
Majesty, His especial licence, that he, the said Francisco Rapozo, 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, his Invention of "CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF STEAM
ENGINES;" in which said Letters Patent there is contained a proviso obliging
him, the said Francisco Rapozo, by an instrument in writing, to cause a par-
ticular description of the nature of the said Invention, and in what, manner
the same is to be performed, to be inrolled in His Majesty's High Court of
Chancery within one calendar month after the date of the said recited Letters
Patent, as in and by the same (relation being thereunto had) may more fully
and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Gregorio Francisco Queiroz, in behalf and as the attorney lawfully authorized
of the said Francisco Rapozo, do hereby declare that the following description,
and the Drawings hereunto annexed, are, the true Specification of the said.

page_text: Invention, and of the manner in which the same is to be performed, that is to
say:
The chief improvements in this steam engine are,
First, in the form and manner of working it, and of communicating its
power to wheels so as to produce a circular motion.
Secondly, in the form of the boiler, which is so constructed as to produce a
greater quantity of steam, and thereby to save fuel.
The form of the engine is as follows:--A (see, the. Drawing annexed,
marked No. 1, in which the same letters refer to the same parts in all the
Figures) represents the cylinder, which is situated horizontally, and in which
the piston K works in the same direction. The shaft of the piston is of equal
length on both sides, to support its motion on the heads B, B, of the cylinder.
To prevent friction there is-a-metal-roller-placed.in.a.bar,.which bar has liberty
to rise and fall, and is kept in its place by a groove. A screw is fixed on the
upper part of this bar, and serves to raise it more or less: By this means the
friction of the bar on the heads of the cylinder, and that of the piston on the
inferior part of the cylinder, are obviated. In the head of the screw is a
wheel, which takes into an endless screw, which projects on one side, and is so
closely fitted into its place that the introduction of the external air is prevented..
By means of this endless screw the other screw fixed in the bar of the roller
is made to raise up gently the shaft of the piston if ever it should be found to.
have sunk in working. In the. upper part of the two heads, of the cylinder
are two boxes C, C, one in each head. A communication between them is
formed by means of a tube, into which is inserted the tube D from the boiler.
Each of the boxes has a valve to. introduce the steam to either of the heads of
the cylinder: In the lower parts of the beads 'B, B, are fixed two tubes, each
having a box E, with a valve, which shuts when the steam is introduced on
that side, and opens when the piston, in consequence of the refrigeration,
reaches the end of the cylinder, thus serving to give a quicker action to the
steam upon the piston. Into the tube under each of these.boxes is inserted a
more slender tube, by which is introduced cold water for the purpose of refri
geration. At the interior extremity F is a little spout turned. upwards, which
throws the cold water against the valve E. This, valve by its concave form
sends back the water without letting it pass into the upper part of the engine™
To the aforesaid tubes are jointed the boxes G, G, and in each of them is a
little valve, which, which when it rises, lets in the cold water for the refri-
gération, and when it falls acts the contrary way.. To this box, at the part
which is situated over the valve, is joined a tube H, which conducts the water
from the cistern I, which is situated above the other parts of the engine;, and

page_text: contains the water used for refrigeration. At the bottom of the tube in which
the refrigeration is made is a valve L, kept in equilibrium by a small counter-
poise N, by means of which it is also kept slightly shut. This valve keeps
in all the water employed in the refrigeration. When that takes place the
valve is shut by the force of the air, and when the valve above it is opened
the steam acts upon the said valve L, which, being at liberty, lets out the water
and the air produced in consequence of the refrigeration. The water thus
expelled falls into the boxes M, M, from which, by means of a tube, it is
carried into the boiler. In the centre of these boxes M, M, is a slender tube,
through which passes the rod of the valve L, and by which also the water used
in the refrigeration finds an issue whenever its quantity exceeds what is neces-
sary to the supply of the boiler. At each side of the shaft of the piston K is
fixed a frame A, A, which on one side takes into a wheel, in the axis of which
a counterpoise may be placed to work the pumps destined to supply the
cistern I with water. On the other side is a bar b, serving to open and shut
the valves. At each end of it are placed rollers to facilitate its motion. The
iron, bar c opens the steam valve d, and shuts the cold water valve at G.
When the piston by means of the refrigeration has reached one end of the
cylinder, it is stopped by a catch placed without till the moment that the
regulator, of whatever form it be, acts upon the spring, and sets the catch at
liberty, by which means the valve of refrigeration is opened and the steam
valve is shut. The bar e is destined to open the valve which is situated above
the place of injection. When the piston reaches the end opposite to the
valve a piece which is fixed in the frame meets the iron bar, and moving it
sets the valve open, which rests upon the catch till the refrigeration has taken
place, after which another piece in the form of a wedge, placed in the bar of
the frame, acts upon the spring and lets fall the valve when the piston comes
near it. It is supposed that the weight of the steam valve in the box C'is
such that, whenever the bar c is at liberty; it can by its weight open the cold
water valve at G.
=
The. way in which the improved steam engine works is as follows:-The
steam from the boiler is let in, and the engine is well warmed on both sides,
after which (supposing all the valves open). the steam valve is shut on that
side from which the motion is to begin. The cold water, valve at G, which
always alternates its motion with the steam valve, immediately opens,' the
refrigeration follows, the piston moves towards that side, and reaching the end
of the cylinder, opens the steam-valve, and sets it on the catch, shutting the
cold water valve, together with that which is situated above the place of refri-
geration. The engine is now prepared for the process of refrigeration on the

page_text: opposite side. The regulator acts upon the spring of the catch on the opposite
side, fixed on the bar c, and setting it loose shuts the steam valve, opening
that of refrigeration, in consequence of which the piston moves towards that
side. When the piston reaches the end of the cylinder the frame produces
again the same series of actions in the opposite direction, and the piston con-
sequently moves to the opposite side; besides which, the frame in this motion
opens the valve situated above the place of injection E, and thus the steam,
filling the cylinder on that side, expels the air and water which before has
produced the refrigeration, and sends them by the valve L to the box M. In
this manner, by these alternate actions, the piston is kept in constant motion
at will, and great varieties of motion may be produced, according to the
different modes of refrigeration which may be adopted, and the variation that
may be made in the manner of opening and shutting the valves. The way of
cominunicating the motion of this steam engine to wheels, or of producing a
circular motion, is as follows:-The teeth of the wheel 2 take into those of
the wheel 1 above it, and into those of the wheel 3 below it. The wheel 2 is
fixed fast on the square of its axis; the other two wheels are moveable on
their axes, but are connected with the wheel 2 by the bars 4 and 5, which
prevent their being displaced, but leave their lateral motion perfectly free.
To the wheels 1 and 3 are joined two catherine wheels, against which act two
catches fixed in the bars 6 and 7, which are connected with a piece fixed in
the head of the shaft of the piston. These catches prevent the motion of the
wheels 1 and 3 in one direction, but leave them at liberty to move the con-
trary way; the wheel 2 always free to move in every direction. If we now
suppose that the engine begins its motion to the left, the two wheels 1 and 3
are forced to the left. The wheel 3 is then stopt by its catch; but the
wheel 2, being free, moves, and imparts its motion to the wheel 1, till the
piston moves to the right. Then the wheel 1 stops against its catch, and the
wheel 3 is moved, and so on alternately at every motion of the piston. In the
intervals between the motions of the piston the large wheel 8 keeps up the
motion of the wheel 2, which is at liberty to turn in the same direction. This
manner of imparting motion to the wheels has the advantage of increasing the
velocity of that wheel which receives the impulse of the machine on whatever
sidė may best suit. The catch may be applied to one or both wheels, ac-
cording as it may be convenient to employ the force of the engine in or two
directions.
Secondly, of the boiler. The boiler is so constructed as to present to the
fire the greatest possible surface in a given space, dividing the bulk of the
water into many smaller parts, in order to produce evaporation more quickly.

page_text: A (see the annexed Drawing No. 2) is the boiler; B, B, B, are spaces or pas-
sages dividing its bottom, which by being so formed presents a greater quantity
of surface to the fire; C is a tube through which the steam is conveyed to the
engine; it is broader at the bottom than at the top, to prevent the boiling
water from going out with the steam; D is an outlet for the steam when the
engine ceases working; E is the place for the coals; F is the fire-place;
G is the ash-hole; H is the chimney. The spaces or passages B, B, B,
at the bottom of the boiler, are only as wide as is necessary for the
purpose of cleaning them. Their number should be in proportion to the size
of the boiler. Their height should be ten inches, and the height of the water
above them should be the same as their breadth. The capacity of A should
be such as to contain a quantity of steam sufficient to supply the engine; and
as the water boils very violently, and the steain ascends with great velocity, it
might be apt to carry up some of the water, for which reason the tube C is
made wider at the bottom, and should also be of sufficient length before it
reaches the engine.
In witness whereof, I, the said Gregorio Francisco Queiroz, have here-
unto set my hand and seal, this Twenty-fourth day of September, in the
year of our Lord One thousand seven hundred and ninety-eight.
GREGORIO FRANCISCO QUEIROZ