IMPROVEMENTS IN STEAM ENGINES
Year: 1856

page_text: LETTERS PATENT to Charles Swift and John James Derham, of Black-
burn, in the County of Lancaster, Engineers, for the Invention of
"IMPROVEMENTS IN STEAM ENGINES."
Sealed the 30th September 1856, and dated the 25th April 1856.
PROVISIONAL SPECIFICATION left by the said Charles Swift and John
James Derham at the Office of the Commissioners of Patents, with their
Petition, on the 25th April 1856.
We, CHARLES SWIFT and JOHN JAMES DERHAM, of Blackburn, in the County
of Lancaster, Engineers, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN STEAM ENGINES," to be as follows:-
We propose to work steam expansively in two cylinders, whether in com-
pound high pressure or compound high and low-pressure steam engines, by
using only one set of valves and side pipes to the low-pressure cylinder, the
said valves having double facings, at angles so arranged as to regulate the due
admission of steam to either of the cylinders. By this arrangement we
dispense entirely with the side pipes and valves to the high-pressure cylinder.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Swift and John James Derham in the Great Seal
Patent Office on the 24th October 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, CHARLES
SWIFT and JOHN JAMES DERHAM, of Blackburn, in the County of Lancaster,
Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Royal
Letters Patent, bearing date the Twenty-fifth day of April, in the year of our
Lord One thousand eight hundred and fifty-six, in the nineteenth year of Her
reigu, did, for Herself, Her heirs and successors, give and grant unto us,
the said Charles Swift and John James Derham, Her special licence that we,
the-said Charles Swift and John James Derham, our executors, administrators,
and assigns, or such others as we, the said Charles Swift and John James
Derham, our executors, administrators and 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 STEAM ENGINES,"
upon the condition (amongst others) that we, the said Charles Swift and
John James Derham, by an instrument in writing under our hands and seals,
or under the hand and seal of one of us, 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 Royal Letters Patent.
⚫ NOW KNOW YE, that I, the said John James Derham, for and on
behalf of myself and the said Charles Swift, do hereby declare the nature of
the said Invention, and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement
(that is to say):-
:-
We propose to work steam expansively in two cylinders, whether in com-
pound high-pressure, or compound high and low pressure steam engines, by
using only one set of slide or conical valves and side pipes to the low-pressure
cylinder, the said slide valves having single or double facings at angles, or
straight facings and passages, so arranged as to regulate the due supply and
exhaust of steam to each cylinder alternately, thereby dispensing entirely with
the side pipes and valves to the high-pressure cylinder, decreasing the radiating
surface, and causing the steam in its passage from one cylinder to the other to

page_text: occupy a much smaller volume than in the arrangements heretofore employed,
and consequently preventing the important loss arising from the cooling and
expansion of the steam, and corresponding decrease in its elastic force, which
invariably occurs when the side pipes are too large, or when two sets are used.
Our improved slide valve or valves may be either in one or two short valves,
connected together in any suitable manner, with the openings so arranged as
to regulate the admission of steam to the tops or bottoms of the respective
cylinders alternately, the slide valves governing the steam openings to the
cylinders having straight or angular facings; conical valves are also applied, if
required, in the place of slides in the valve box.
These improvements will be clearly understood by referring to the accom-
panying two Sheets of Drawings, with the figures and letters of reference
thereon, for the arrangement of slide valves, the said letters referring to similar
parts in all the Figures.
Fig. 1 is a longitudinal elevation, in section, of part of a double cylinder,
engine to which our improved slide valves only are applied; Fig. 2 is a plan
of the same; Fig. 3 is a sectional elevation of the low-pressure cylinder,
showing our improved slide valve or valves and side pipes, which allow the
supply of steam to and exhaust from the high-pressure cylinder without an
additional slide valve or valves or side pipes; Fig. 4 is a sectional plan of the
same at the dotted line A, B; Fig. 5 is a front elevation of cylinder and side
pipes, having the lower valve box cover removed; and Fig. 6 is a sectional
plan of the cylinder and side pipes at the dotted line C, D.
In Figs. 1 and 2, Sheet 1, representing part of a double cylinder engine,
a is the low-pressure cylinder; b, the high-pressure cylinder; c, the upper box
of the side pipes; d, the lower box; and e, the column or pipe which con-
nects them. The pipes for supply and exhaust to and from the high-pressure
cylinder are shewn at f and g. The steam is passed from the valve box c along
the pipe f to the top of the high-pressure cylinder b, and after doing duty in
the high-pressure cylinder it escapes back again along the pipe f to the top
of the low-pressure cylinder a, when it is expanded, and at. the return stroke of
the piston the steam is passed from the valve box d along the pipe g to the
bottom of the high-pressure cylinder 6', and from there it escapes back again
along the pipe g to, the bottom of the low-pressure cylinder a¹, when it is also
expanded.
In Figs. 3, 4, 5, and 6, Sheet 2, the low-pressure cylinder and side pipes
are shewn detached, and drawn to an enlarged scale. h, h', represents the
passages from the side pipes and inner spaces of the valves to the low-pressure.
cylinder. i, the pipe from the boiler to supply steam to the side pipes; k, k¹,

page_text: the passages to the condenser; 1, a blow-through valve; m, m³, steam pipes or
passages, cast to or connected with the upper and lower boxes of the side pipes;
to which the supply and exhaust pipes ƒ and g are connected, the surfaces
surrounding the inner passages m, m', being made true in the usual manner:
Our improved valves are shewn at n, n', fitting correctly the surfaces of the
passages h, h, to the low-pressure cylinder k, k; to the condenser, and m, m³,
to the supply and exhaust pipes ƒ and g of the high-pressure cylinder, and as
shewn in the Drawings (Sheet 2), Figs. 3 and 4, these passages are at
angles to each other, the surfaces of the valves corresponding with them. The
inner spaces of the slide valves are so arranged that they are open to the high
and low-pressure cylinders and condenser when required. The spaces or
passages o, o', in the valve correspond in the up and down stroke with the
-inner passages m, m³, for steam and exhaust to and from the high-pressure
cylinder. When two valves are applied, they move simultaneously, and are
connected by a rod in the usual manner.
In Fig. 3, Sheet 2, the valves are shewn at half stroke, and passages m, m³,
leading to and from the high-pressure cylinder are closed, thus preventing the
admission of steam to the high-pressure cylinder; the slide valves also cover
the passages for supply and exhaust to the low-pressure cylinder. The opera-
tion of our said improved valves is as follows:-If the valves move downwards
to the position shewn by the dotted lines, the passage m in the top valve box.
is uncovered, allowing steam from the side pipes to enter the pipe f, and be
conveyed to the upper part of the high-pressure cylinder; at the same time the
passage o¹ in the lower valve is opposite the passage m³, leading to and from
the pipe g, which is now the exhaust pipe, from the bottom of the high-
pressure cylinder and supply to the low-pressure cylinder, the steam passing
through the passages m' of the box, and o¹, internal space of the valve n¹, and
passage h', to the under side of the piston p in the low-pressure cylinder; the
steam from the upper side of the low-pressure cylinder being exhausted
through the passage h, inner space of the valve n, and passages k, leading to
the exhaust branch q, connected with the condenser. For the opposite stroke
the operations are simply reversed, the lower pipe g supplying steam to the
high-pressure cylinder, and the upper pipe f becoming the exhaust therefrom;
thus the steam is made to act upon the pistons of two cylinders by means of
one set of valves and side pipes, which gives a great increase of power by.
maintaining the steam in its most efficient condition, and by the low-pressure
cylinder getting the benefit of the high-pressure volume of steam contained in
the pipes f and g.
Ilaving thus fully described the nature and particulars of our said Inven-

page_text: tion, and the manner of carrying the same into practical effect, we desire it to
be distinctly understood that we claim as our Invention, and which, to the best
of our knowledge and belief, has not been hitherto used within this realm, the
application of the valves and side pipes to engines, as herein described, and
illustrated in the accompanying two Sheets of Drawings.
In witness whereof, I, the said John James Derham, for and on behalf
of myself and the said Charles Swift, have hereunto set my hand and
seal, this Twenty-first day of October, One thousand eight hundred and
fifty-six.
JOHN JAMES DERHAM. (L.B.)
Signed, sealed, and delivered by the within-
named John James Derham, in the
presence of
E. J. HUGHES,
Patent Agent,
Manchester.