CERTAIN IMPROVEMENTS IN PROPELLING AND IN PROPELLING- MACHINERY
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOSEPH
MAUDSLAY and JOSHUA FIELD, of Lambeth, in the County of Surrey, Engineers,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-fourth day of April, in the eighth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
Joseph Maudslay and Joshua Field, Her especial licence, full power, sole
privilege and authority, that we, the said Joseph Maudslay and Joshua Field,
our exors, adiñors, and assigns, or such others as we, the said Joseph Maudslay
and Joshua Field, our exors, adññiors, or assigns, should at any time agree
with, and no others, from time to time and at all times during the term of
years therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, my
Invention of "CERTAIN IMPROVEMENTS IN PROPELLING AND IN PROPELLING-
MACHINERY;" in which said Letters Patent is contained a proviso that we,
the said Joseph Maudslay and Joshua Field, shall cause a particular descrip-
tion of the nature of our said Invention, and in what manner the same is to
be performed, under our hands and seals, or under the hand and seal of one
of us, to be inrolled in Her said Majesty's High Court of Chancery within
six calendar months next and immediately after the date of the said in part
recited Letters Patent, as in and by the same, reference being thereunto had,
will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, we, the said
Joseph Maudslay and Joshua Field, hereby declare that the nature of the
said Invention, and in what manner the same is to be performed, are fully
described and ascertained in and by the present Specification thereof, reference
being had to the Drawings hereunto annexed.
The improvements in which our said Invention consists have relation to the
propelling of steam vessels and to the machinery employed therein, and more
particularly to the propelling of them through the instrumentality of screw
and other submerged propellers, and are as follows:-
First, we employ, for the purpose of propelling screw and other submerged
propellers, a steam engine of a new construction, to which we give the name
of "the horizontal double-cylinder engine." It has two steam cylinders, the
joint areas of which are equal to the area of a cylinder of ordinary dimensions,
that is to say, supposing the engine were required to be of one hundred horses
power, the cylinders would each be of an area equal to a portion of the 100
horses power, as, for example, the two cylinders may be of 50 horses power
respectively, or of 60 and 40, or of 70 and 30, and these cylinders are placed
horizontally end to end in the same straight line, but with space enough
between them to allow of the movement to and fro of their respective piston
rods and appendages. The piston of each cylinder has two rods (instead of
one as usual), and the two pairs of piston rods are connected to one common
cross head which acts through one connecting rod on one crank attached to
the propeller shaft. Figure 1 of the Drawings hereunto annexed represents
a top plan of a pair of engines of this description, as fixed in a steam vessel
and applied to a screw propeller; Figure 2 is a transverse elevation on the
line a, b, of Figure 1; Figure 3 is an end view on the line c, d, of Figure 1;
and Figure 4, a transverse view on the line e, f, of Figure 1. A, B, are the
two cylinders; a¹, a², the two rods of the piston of the cylinder A; and b', b,
the two rods of the piston of the cylinder B. D is the cross head to which the
two pairs of piston rods are attached. One rod of each pair is placed above
the cross head and the other below it, and the four rods are so placed in this
respect in relation to one another, that the two rods which are above the cross
head shall be diagonally the opposite of one another, and the two rods which
are below it the like. For example, if a¹ of one pair is placed above the
cross head, then 62 of the other pair must be also above it, and a² and be
the two rods which are placed below it. The cross head D has a bearing in
the middle of it for the connecting rod E, and prolongations, one at each end,
which serve as a guide for the rod. F is the crank on the propeller shaft
having bearings G, G, in the frames H, H, which serve both to connect the

page_text: two cylinders and as guides for the cross head. I, I, are slide valves for
regulating the inflow and outflow of the steam to and from the cylinders,
which may either be connected together and worked by one eccentric, or may
be worked independently, each by means of a separate eccentric. J, J, arc
the condensers.
And, second, we apply to horizontal steam engines horizontal air pumps
(double or single acting), and worked in the manner shewn on the left-hand
side of Figure 1 and Figure 2 of the Drawings hereunto annexed, where the
pump is represented as of the double acting sort. K is the barrel of the pump;
L, the piston or plunger; M, the piston rod which passes through a stuffing box
in the outer cover of the cylinder B, and is attached directly to the piston of
the steam cylinder so as to derive its motion therefrom; N is the lower foot
valve at the end of the passage P, which communicates with the condenser
and leads to the space P2 on one side of the piston or plunger; Q is another
foot valve at the end of the passage R, which communicates in like manner
with the condenser, and leads to the space R³ on the opposite side of the
plunger; T, T, are discharge valves placed on openings over the space R², and
U a similar discharge valve placed in an opening over the space P2; V is the
cistern or hot well; and W is the discharge pipe for the ejection of the air
and water overboard. When the air pump is single acting (which, however,
we do not consider so suitable as the double-acting pump just described), it is
made with valves on the plunger as usual.
And having now described the nature of our said Invention, and in what
manner the same is to be performed, we declare, that though we have under
the first head of our Invention described each piston as having only two
piston rods, yet that it may be made with three, four, or more rods, taking
care only to place these rods at equal distances from one another and from the
periphery of the piston, and dispensing with the diagonal arrangement before
described, where the number of rods does not admit of it; and we declare that
what we claim is,-
First, the horizontal double-cylinder engine before described, consisting of
two cylinders placed horizontally end to end in one straight line, but suffi-
ciently apart to allow of the movement to and fro of their respective piston
rods and appendages, and each provided with two or more piston rods which
are connected (that is to say, the rods of both pistons,) to one common cross
head, which acts through one connecting rod on the crank shaft, whereby both
pistons are brought to act simultaneously on the propeller shaft, all as before
described; and, second, the application of a horizontal air-pump; double or single,
acting, in manner before described, to horizontal marine steam engines, whether

page_text: of the double cylinder sort first herein-before described and claimed, or of any
other sort, and whether the piston or plunger of the air pump is worked
directly from the piston of the steam engine, or in any other way.
In witness whereof, I, the said Joseph Maudslay, on behalf of myself
and the said Joshua Field, have hereunto set my hand and seal, this 5
Twenty-second day of October, in the year of our Lord One thousand
Enrolled the Twenty-fourth day of October, in the year of our Lord One
thousand eight hundred and forty-five.