IMPROVEMENTS IN. MOTIVE POWER ENGINES
Year: 1855

page_text: LETTERS PATENT to William Elliot Carrett, of the Sun Foundry, Leeds,
in the County of York, Engineer, for the Invention of "IMPROVEMENTS
IN. MOTIVE POWER ENGINES."
Sealed the 3rd July 1855, and dated the 28th April 1855.
PROVISIONAL SPECIFICATION left by the said William Elliot Carratt
.
at the Office of the Commissioners of Patents, with his Petition, on
the 28th April 1855.
I, WILLIAM ELLIOT CARRETT, of the Sun Foundry, Leeds, in the County
of York, Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN MOTIVE POWER ENGINES" to be as follows:-
This Invention relates to certain peculiar constructions and arrangements of
steam or motive power engines, whereby the expansive action of high-pressure
steam or other elastic medium is now advantageously developed before it is
finally suffered to escape into the condenser or is discharged into the
atmosphere.
According to one arrangement, the piston or pistons of the engine are
attached on one side to one or more "rams" or "trunks" or tubular "piston
rods" of any convenient sectional form, passing by suitable steam-tight packing
thro' the end of the cylinder, for the purpose of reducing the effective steam
surface on that side of the piston, the high-pressure steam or other elastic

page_text: medium being first admitted into the cylinder by suitable valve arrangements
upon such reduced steam surface of piston, where it is partially expanded
before it is afterwards permitted to enter the opposite end of the cylinder, and
by its remaining expansive to act upon the other side of such piston, having a
larger effective area, thus completing the double stroke, after which the steam
is discharged into the atmosphere or condensed in a suitable manner. Each
such piston of an engine works in a separate and distinct cylinder of its own,
whether one or more cylinders be employed, the ends of such cylinders being
closed, either one or both of them being fitted with the requisite steam-tight
packing chambers. In this arrangement, the motive power may be transmitted
by a connecting rod or link or links either from the end of the trunk or inside
the same; or it may be attached "direct," as in oscillating cylinder engines;
or the power may be similarly transmitted by a piston rod or rods passing out at
the opposite end of the cylinder. By a further arrangement or modification, the
piston may be fitted on one side with one or more trunks or rams passing
through the end of the cylinder into a closed chamber or chambers which are
in communication with the condensor, or may further be made to serve as the
air pump of the engine or engines, such trunks or rams and chamber or
chambers being furnished with suitably arranged steam-tight packing to
prevent the escape of steam from the cylinder. The power may be applied
either from a piston rod or rods at the end of such trunks or rams and passing
through the end of the closed chamber or chambers, or by a piston rod or rods
attached to the opposite side of the piston passing through the end of the
cylinder; or, if deemed advisable, the latter may be replaced by a ram or trunk
passing through the end of the cylinder, as herein-before described in the
1st arrangement; the steam in this case, as in the previous instances, being
admitted first upon the lesser effective area of the piston, and afterwards upon
the greater effective area, before it is finally suffered to escape.
According to a third modification, one or more trunks or rams may be
attached to each side of the piston, those on that side of the piston upon which
the steam is first admitted being arranged in either of the previously specified
modes, while those on the opposite side of the piston (which serve principally
as guides to direct and support the same) slide in closed chambers on the end
of the cylinder or cylinder cover, so arranged as to allow the steam to act upon
the ends of such trunks or rams simultaneously with that side of the piston.
This may be effected either by having the trunks or rams of a different section
to that of the chamber or chambers, and thus allowing the steam to pass into
the end of the closed chamber or chambers along the side or sides of the

page_text: trunks or rams; or the trunks or rams may he made to fit the chambers, and
the steam admitted by a steam port or passage into the end of such chambers.
The power may be applied either through the end of such chamber or cham-
bers by a suitable piston rod or rods, or from the end of the trunk or trunks,
or through the inside of the same, by a connecting rod or link or links.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Elliot Carrett in the Great Seal Patent Office on
the 26th October 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ELLIOT CARRETT, of the Sun Foundry, Leeds, in the County of York, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of April, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Elliot Carrett, Her special license that I, the said
William Elliot Carrett, my executors, administrators, and assigns, or such.
others as I, the said William Elliot Carrett, my executors, administrators,
or assigns, should at any time agree with, and no others, from time to time
and at all times thereafter.during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN MOTIVE POWER ENGINES," upon the condition
(amongst others) that I, the said William Elliot Carrett, by an instrument
in writing under my hand and seal, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said William Elliot Carrett, do hereby
declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement, referenco being had to the accompanying Drawings, and
to the letters and figures marked thereon, that is to say :-

page_text: My said Invention relates to certain peculiar constructions and arrangements
of steam or other motive power engines, whereby the expansive action of high-
pressure steam or other elastic medium is more advantageously developed
before being finally suffered to escape into the condenser or is discharged into
the atmosphere.
The class of engine to which these improvements apply (whether having
one or more cylinders in any required position as may be found convenient)
are those in which the high-pressure steam or other elastic medium is first
permitted to operate on a portion of one side of the piston or pistons contained
within such steam cylinder or steam cylinders, and afterwards the same steam
is allowed to act a second time on the opposite or larger effective area of such
piston or pistons, thus completing the required amount of expansion, and
effecting the return stroke of the engine before being finally suffered to escape
into the atmosphere or condenser.
And in order that the said Invention may be fully understood, I shall now
proceed particularly to describe the same, and for that purpose I shall refer to
the several Figures on the Sheets of Drawings hereunto annexed, the same
letters of reference indicating corresponding parts throughout all the Figures.
Figure 1 represents one of such modifications. A is the steam cylinder;
B, the piston; C, one or more trunks, rams, or plungers, (either open or closed
at one end, as may be deemed expedient), attached to and moving simul-
taneously with the piston B, and passing through the end D of the cylinder
into one or more suitable closed chambers or cylinders E in connection there-
with, and arranged in such a manner as to prevent the escape of steam from the
steam cylinder A into the same. F is the steam port through which the high-
pressure steam is first admitted, into the cylinder, which steam, by its action on
the annular effective area of the piston on that side, imparts motion to it, as
well as to the trunk, ram, or plunger attached thereto, the effect of which is to
cause a vacuum inside such closed chamber or cylinder E, (and which in the
condensing engine can be further assisted by its being put in communication
with the condenser,) the effect of such vacuum being to subject the piston to a
continuous force operating in an opposite direction to that produced upon it by
the steam on first entering the cylinder through the port F, this force assisting
the available power produced upon the piston by the steam on its second
admission into the cylinder through the port G, thus serving to equalize the
useful effect developed by the piston in both directions of its path.
Another modification of this arrangement can be effected by constructing
such closed chamber or cylinder E with suitable inlet and outlet clacks, valves,

page_text: or slides in connection with the condenser and hot well, so as thereby to
become the air pump of the engine, as shewn in Figure 2. A is the steam
cylinder; B, the piston; C, the plunger, ram, or trunk attached to such
piston; E, the closed chamber or cylinder, which, by the inlet and outlet
clack H, I, and their passages, thereby becomes the air pump of the engine.
The motive power in this, as in the previous instance, can be applied either
through a suitable rod or rods attached to either side of the piston, or from the
end of the trunk, ram, or plunger in the usual manner.
as
According to the arrangement shewn at Figure 3, the trunk or ram C of
the piston B on that side on which the steam first operates is so constructed
to pass steam-tight into a conveniently disposed closed vacuum chamber E or
otherwise, as is shewn in Figures 4 and 5, in which Figures such trunk
or ram C, on the same side of the piston B above referred to, passes steam-
tight through the cover of the cylinder A into the atmosphere, having its end
either closed or open, as may be found convenient. I further, in these my
improvements, attach to the opposite side of the piston B, on which the steam
acts when admitted a second time into the steam cylinder through the port G,
one or more additional trunks or rams J, of suitable sectional form, and sliding
in a conveniently arranged steam chamber or chambers, cylinder or cylinders
K, in connection with the other end L of the steam cylinder A, in such a
manner as not to decrease the effective area on such-side of the piston when
subject to the action of the steam or vacuum. To accomplish this, I allow a
portion of the same steam which is allowed to enter the port G to be admitted
simultaneously by suitable passages into the end of the steam chamber K,
which passages serve also for the egress of such steam..
443
The means to be employed are various; three of which I will name, but I do.
not confine myself to such only. A suitable steam passage or passages may
either be constructed in the chamber itself, in connection with the end of the
cylinder. L, as is shewn in section M, N, or the trunk or ram may be made of;
a different sectional form to that of the chamber in which. it slides, as is shewn
in section O, P; or, if convenient, the steam may be allowed to pass through
the ram or trunk into the end of the steam chamber or cylinder, as shewn in
section Q, R, by which or any other means the effective area of the ram or
trunk is simultaneously acted upon along with the remaining portion of tho
piston's effective area on that side.
25
This additional trunk or ram J assists in guiding and supporting the piston,
and also serves as a ready means of increasing the length of the connecting
rod when it is deemed advisable to allow it to vibrate inside the same, as is.

page_text: shown in Figure 4. Instead of transmitting the power through a piston rod
or rods from either side of the piston, or from either ends of such trunks or
rams through the usual stuffing boxes, as in Figure 5, the end of the trunk or
ram C
be attached to the crank direct, the cylinder A and its appendages
being thereby allowed to vibrate.
may
The arrangement shewn in Figure 3 illustrates also another method of
applying the power developed by the piston B to the crank S. In this instance
the closed vacuum chamber E, referred to in the previous Figure 1, is slightly
modified in form, so as to allow the crank and part of its shaft to revolve
inside the same, and in such a manner as to exclude the external atmosphere,
whilst the connecting rod at its other end is attached to either of the trunks,
so as to allow it to vibrate inside the same. But I may here observe that I
lay no claim to this peculiar mode of applying the power developed from the
piston to a crank inside such vacuum chamber. In all of the above instances,
in which the same steam acts alternately on the effective area of each side of
the piston, the side of such piston opposite to that on which the steam is first
allowed to operate is simultaneously open to the atmosphere when such engine
is non-condensing, or when such engine is constructed on the condensing
principle such side is simultaneously open to the condensor.
.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe, in conclusion, that I do not confine or restrict myself
to the precise details or arrangements which I have had occasion to describe
or refer to, as many variations may be made therefrom without deviating from
the principles or main features of my said Invention; but what I consider to
be novel and original, and therefore claim as the Invention secured to me by
the herein-before in part recited Letters Patent, is,―
First, the general constructions and arrangements of certain parts of steam
engines in which the same steam acts alternately on each side of the piston or
pistons, as herein-before described.
Second, the application and use in engines of the above class of one or more
trunks, rams, or plungers attached to that side of the piston on which the
steam first operates, such trunks, rams, or plungers working steam-tight in
one or more suitable closed cylinders or vacuum chambers attached to the end
of the steam cylinder.
Third, the constructing of the closed cylinders or vacuum chambers herein-
before referred to so as to constitute or form the air pump or pumps of the
engine, as herein-before described.

page_text: Fourth, the application and use in engines wherein the same steam is
admitted alternately on each side of the piston, of one or more trunks, rams, or
plungers attached to the opposite side, of the piston to that on which the steam
first operates, but so arranged as not to diminish the effective area of that side
of the piston.
In witness whereof, I, the said William Elliot Carrett, have hereunto
set my hand and seal, the Twenty-fourth day of October, One thousand
eight hundred and fifty-five.
WILLIAM ELLIOT CARRETT. (L.s.)