An IMPROVED COMBINED EXPANSIVE STEAM AND ATMOSPHERIC ENGINE
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, SAMUEL
TRETHEWEY, of Water Grove Mine, near Stony Middleton, in the County of
Derby, Civil Engineer, and JOSEPH QUICK, of Sumner Street, Southwark, in
the County of Surrey, Engineer, send greeting.
WHEREAS Her present most Excellent Majesty hath granted unto us Her
Letters Patent, bearing date at Westminster, the Twelfth day of July, in the
ninth year of Her reign, for making, using, exercising, and vending, within
that part of the United Kingdom of Great Britain and Ireland called England,
Her Dominion of Wales, and Town of Berwick-upon-Tweed, and also in all
Her said Majesty's Colonies and Plantations abroad, our Invention of "An
IMPROVED COMBINED EXPANSIVE STEAM AND ATMOSPHERIC ENGINE;" subject to
the usual proviso obliging us to particularly describe and ascertain the nature
of our said Invention, and in what manner the same is to be performed, by
an instrument in writing under our hands and seals, or under the hand and
seal of one us, and to cause the same to be enrolled in the High Court of
Chancery within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that in compliance with the said proviso, we, the said
Samuel Trethewey and Joseph Quick, do hereby declare and ascertain the
nature of our said Invention to consist in an improvement in expansive steam.

page_text: engines, viz., in the working thereof by expansive steam and the atmosphere
combined. And in further compliance with the said proviso, we, the
said Samuel Trethewey and Joseph Quick, do hereby further particularly
describe and ascertain the nature of our said Invention, and in what manner
the same is to be performed, by the following Statement thereof, reference
being had to the Drawing annexed, and to the letters marked thereon, that
is to say) :-
The Drawing represents a longitudinal section of our Improved Combined
Expansive Steam and Atmospheric Engine, the application of our Invention
being shewn in the coloured portions of such Drawing; and the following is a
description of such Drawing (that is to say):-
A is the steam cylinder and jacket; B a steam and atmospheric cylinder
and jacket; C, the piston of the steam cylinder; D, the piston of the steam
and atmospheric cylinder; E, piston rod, connecting the piston of the steam
cylinder to the parallel motion F, F, F, F; E, piston rod connecting the
piston of the steam and atmospheric cylinder to the same parallel motion;
F, F, F, F, the parallel motion; G, the beam; H, steam nozzles and valves;
I, equilibrium pipe; J, equilibrium valve; K, passage under the cylinders;
L, pipe in connection with steam and atmospheric cylinder; M, exhausting
nozzle and valve; N, eduction pipe; O, condenser; P, air pump Q, Q, Q
stand gear and steam tappets. The steam cylinder A which takes the steam
from the boiler is covered at the top in the usual way, and is fixed under the
extremity of the beam G. The steam and atmospheric cylinder B is fixed or
stands towards the centre of the beam G, and is left uncovered at the top, so
that the atmosphere may bear its full pressure on the upper surface of the
piston D in that cylinder. The comparative diameters and sizes of the two
cylinders A and B should be so regulated that the high steam leaving the
steam cylinder A should balance the atmosphere in the steam and atmospheric
cylinder B, which will be easily understood by practical persons, and the cylin
ders may be placed relatively to each other either as shewn in the Drawing,
and which, in our opinion, will in all cases be the preferable mode, or they and
their respective gear may be reversed in their positions, the steam cylinder A
and its gear being placed towards the centre, and the steam and atmospheric
cylinder B and its gear being placed on the outside; but the steam cylinder
A must in that case be made shorter and proportionably large in diameter,
and the steam and atmospheric cylinder B longer and proportionably less in
diameter, in order to accommodate themselves to the stroke of the engine.
After creating a vacuum in the cylinders and passages in the usual way we
proceed as follows:-The steam passes from the boiler to the steam cylinder

page_text: A through the steam nozzles and valve H, and enters on the upper surface.
of the piston C, and causes such piston to descend to the bottom of the steam
cylinder A, and at the same time the piston D being acted upon by the
atmosphere in consequence of being left open at the top, descends to the
bottom of the steam and atmospheric cylinder B, and thus the down stroke
or first motion to the engine is given. At the termination of the down stroke
the equilibrium valve J opens, and allows the steam from the upper surface of
the piston C to descend through the equilibrium pipe I, and so to equalize the
pressure under and over the piston C, and at the same time to pass on through
the passage K, up the pipe L, and under the piston D of the steam and atmo-
spheric cylinder B, thereby counterbalancing the atmosphere in that cylinder,
and assisting the up stroke of the engine. At the termination of the up stroke
the exhausting valve M opens, and the steam from under both pistons then
passes through such valve into the eduction pipe N to the condenser O, where
the condensation of that steam is effected by the admission of cold water in
the usual way, thus producing a vacuum under both pistons to assist the
down stroke of the engine, and the water is then pumped out through the
air pump P in the usual manner, and so the working of the engine is con-
tinued on as before described. Now it follows from our Improved Combined
Expansive Steam and Atmospheric Engine that the engine is worked by means
of expansive steam and the atmosphere combined, the atmosphere acting upon
the piston D in the steam and atmospheric cylinder B, being used in combi-
notion and simultaneously with the steam in the steam cylinder A to effect the
down stroke of the engine, and the steam from the steam cylinder A, which
may be worked at a high pressure and at a uniform density throughout the
entire length of the stroke of such cylinder, being used to counterbalance or
counteract the atmospheric pressure on the piston D of the steam and atmo-
spheric cylinder B in the up stroke of the engine, and whereby more power
will be added to the engine, whilst a great saving in fuel will be effected and
much trouble saved. Now, whereas we do not intend to confine our said
Invention to any particular description of expansive steam engines, the same
being applicable to all descriptions of expansive steam engines, but we have
described the mode of using and applying our said Invention for the purposes
herein described in the most plain and simple mode in our apprehensions to
enable any practical person to apply the same to all descriptions of expansive
steam engines. And we claim as our Invention,-
First, this improved mode of constructing and arranging expansive
steam engines for the working thereof by expansive steam and the atmosphere
combined, as above described.

page_text: Second, the working of expansive steam engines by expansive steam and
the atmosphere combined, in the manner above described.
And such our said Invention being, to the best of our knowledge and belief,
entirely new and never before used within that part of Her said Majesty's
United Kingdom of Great Britain and Ireland called England, Her said
Dominion of Wales, or Town of Berwick-upon-Tweed, or in Her said
Majesty's Colonies or Plantations abroad, and we do hereby declare
this to be our Specification of the same, and that we do verily believe this
our said Specification doth comply in all respects, fully and without reserve
or disguise, with the proviso in the said herein-before in part recited Letters
Patent contained; whereupon we hereby claim to maintain the exclusive right
and privilege of or to our said Invention.
In witness whereof, I, the said Joseph Quick, have hereunto set my
hand and seal, this Twelfth day of January, in the year of our Lord
One thousand eight hundred and forte-siz