IMPROVEMENTS IN MACHINERY FOR PROPELLING
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
SEAWARD, of the Canal Iron Works, Poplar, in the County of Middlesex,
Engineer, 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 Fifth day of February (One thousand eight hundred and
forty-five), in the eighth year of 1er reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said John Seaward, Her especial
licence, full power, sole privilege and authority, that I, the said John
Seaward, my exors, adññiors, and assigns, or such others as I, the said
John Seaward, my exors, adñiors, 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 "IMPROVEMENTS IN MACHINERY FOR PROPELLING;" in which said Letters
Patent is contained a proviso, that I, the said John Seaward, shall cause a
particular description of the nature of my said Invention, and in what
manner the same is to be performed, 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, I, the said
John Seaward, hereby declare that the nature of my Invention, and in
what manner the same is to be performed, are fully set forth and described in
the present Specification thereof, reference being had to the Drawings hereunto
annexed (that is to say) :-
The first of my improvements in machinery for propelling relates to the
class of steam engines called direct-acting, and consists in so constructing
the connecting rod, or that rod which connects the piston rod with the crank.
that the length thereof can be encreased without encreasing the height of the
engine, as compared with the usual mode of construction.
Sheet No. I. of the Drawings hereunto annexed exhibits so much of an
engine of this description as is necessary to shew this improvement. Figure 1
is a vertical section in the direction of the line of shafts, and Figure 2 a plan
on the line a, b, of Figure 1. A is the piston, and B the piston rod; C is a
short cross-head secured to the top of the piston rod, from which two vertical
arms descend through the upper surface of the cylinder cover into recesses
R, R, formed within the cover (to which there are corresponding recesses in
the piston A), where, taking bend at right angles to their first vertical
direction, they terminate in bearings or gudgeons g, g, having the smaller
prolongation j, j; D is a rod connected at top to the crank, and terminating
at bottom in two forks, which are jointed to the gudgeon ends g, g, of the
cross-head C; F, F, are guide rods for preserving the parallelism of the other
parts (B, C, D, and g, g), which are connected to sliding or friction pieces
p, p, fixed on the prolonged ends j, j, of the gudgeons g, J.
The second of my said improvements has reference to marine steam engines
generally, and consists in a mode or modes of producing the requisite draught
in the furnaces, and carrying off and depurating the products of combustion,
whereby the ordinary funnels or chimneys are dispensed with, the vapours
emitted into the atmosphere are of a less dark color than usual, steam vessels
are rendered not distinguishable at considerable distances from other vessels,
and the risk of being disabled is greatly diminished.
Figure 1 of Sheet No. II. of the Drawings hereunto annexed is a longi-
tudinal and vertical section of as much of the after part of a steam vessel
as is necessary to shew these improvements. L is the engine room, a plan of
which is given separately in Figure 2, and M the after hold; A, A, are the
furnace and boilers; a is an uptake, or vent, which leads from the furnace by
a pipe into a smoke chamber or receiver N, placed at the back of the boilers,
which communicates by the means to be presently explained with a second
chamber O, and that with a long pipe E, which leads to the outside of the

page_text: vessel at the stern or sides; B, B, B, are three double-acting air-pumps,
which are placed between the two receivers N and O, and communicate with
both, acting by the force of exhaustion upon the one (N), so as to draw the
smoke, heated air, and other products of combustion in a strong current from
the furnace or furnaces, and by the force of compression upon the other (O),
so as to drive the said products through O and the pipe E, and out at the
stern or sides of the vessel. These air-pumps are worked by means of a pair
of small steam engines C, C, (Figure 2,) which are separate and distinct from
the principal engines employed to propel the vessel, and are supplied with
steam from a small boiler D, which is also separate and distinct from the
large boilers A, A. The furnace of the small boiler D communicates by a
smoke flue (not seen in the Drawings) with the chamber N, whereby the
air-pumps exert the same drawing or exhausting effect on it as on the larger
furnace, and the smoke and other products of combustion issuing from it
mingle with and take the same course as the others. To set the small engines
and boiler at work, in the first instance, I employ a small fan or blower,
worked by hand or otherwise; but as soon as suflicient steam is raised to
work the air-pumps, (B, B, B,) the use of the fan or blower is discontinued.
The receivers N and O are each divided longitudinally near to the top by two
plates P and Q, perforated with a number of small holes; and into the
chambers W, W, thus formed at the top of each, a continuous supply of water
is poured from the taps p and q, whence it descends in finely divided showers
through the smoke and other products of combustion as they pass through
the receivers (N and O), serving to cool them down, and to precipitate a
considerable portion of the fuliginous or dark coloring matter with which they
are intermixed. R¹, R², are two waste pipes, with taps for drawing off the
foul water as it collects at the bottom of the receiver N and O. To prevent
the great smoke discharge pipe E from becoming too heated, it is enclosed in
another pipe, with a distance of about an inch or two between them, and a
stream of cold water is kept flowing continually between the two pipes. L'is
a stop valve (opening outwards only), which is placed near the end of the
pipe E, to prevent any resurging of water from the pitching of the vessel or
otherwise. Separate views of the receivers, air-pumps, and small engines, and
on a larger scale than in Figures 1 and 2, are given in Figures 3, 4, and 5.
Figure 3 is a side view, partly in section, of the air-pumps (B, B, B,) and
smoke receivers N and O, showing the crank shaft (F) and cranks (c, c,) by
which they are worked in connection. I prefer using three double-acting pumps,
as here represented; but they may be either single or double-acting, and either
one, two, or more may be employed, according to the size of the principal

page_text: engines. Figure 4 is a transverse section on the line a, y, of Figure 3;
Figure 5 is a plan of the parts separately represented in the other four
Figures.
The third of my improvements consists in the mode represented in
Figures 1 and 2 of Sheet No. III. of the Drawings hereunto annexed, of
freeing the water supplied to the boilers of marine steam engines from any
sand, mud, or other foreign matters which may be mechanically intermixed
therewith. For this purpose the water is passed through a filter constructed
in the manner shewn in section and in plan in Figures 1 and 2. A is a
square vessel which communicates by a pipe F at bottom with the feed-pump,
and by a pipe G at top with the boilers. The body of this vessel from a to b
is occupied by a number of shallow boxes E, E, the tops and bottoms of which
are perforated all over with small holes, each of which boxes is filled with
screened gravel, coarse sand, moss, sponge, flannel, or some other suitable
filtering material. These boxes slide in and out in grooves, or on ledges
formed on the sides of the vessel. a and b are two partition plates perforated
in the same way as the boxes, by which two chambers B and C are formed,
one at the bottom of the vessel, to receive the water to be filtered, and the
other at the top, where it collects after it has by its passage upwards through
the boxes E, E, been filtered. The vessel is closed in front by a strong door d, d,
with water-tight joints, by opening which the boxes can be removed for the
purpose of renewing or cleansing the filtering materials as often as may be
required.
The fourth of my improvements has relation to that description of propelling
machinery in which the propulsive effect is obtained by the reaction of water
forced out at the stern or sides of a vessel, and consists in working the pistons
of the cylinders and water-pumps by one rod common to both (instead of by
separate rods, as has been heretofore proposed), and in a better mode of
regulating the discharge of the water from the ejecting pipe. The arrange-
ments which I propose for this purpose are represented in Sheet No. 1V. of
the Drawings hereunto annexed. Figure 1 is a longitudinal and vertical
section of the machinery, which is supposed to be placed in the usual engine
room of a steam or other vessel. Figure 2 is a sectional plan, one part on the
line Y, Z, and the rest on the line Y, Z", of Figure 1. Figure 3 is a
transverse section on the line L, M, of Figure 2. A, A, A, are three steam
cylinders fixed securely in a horizontal position, and a', a", a, are the pistons
of these cylinders, which are furnished with double or fore and aft piston
rods g, g, g, working through stufling boxes in the ends of the cylinders.
B, B, B, are three water cylinders or pumps, so fixed that their centres

page_text: shall exactly coincide with the centres of the steam cylinders, A', A", A", and
which are open at the ends, but are furnished each with a solid piston or
plunger h', h, h. The double piston rods g', 9", g, are prolonged aft to
such an extent as to be attached to and serve as the rods to the pump pistons
h', h", h¹¹¹; X, X, is a large chamber into which the pumps open aft. This
chamber is divided vertically into two compartments D and E, and these again
are subdivided as follows:-the compartment D is subdivided vertically into
three compartments d³, d", d¹¹, (one to each pump barrel,) and the compart-
ment E is subdivided horizontally into two compartments e¹, e¹¹.
The vertical division plate between D and E is furnished in that part which
is opposite the compartment e¹ (see Figure 1) with valves opening inwards
towards the pumps, and in that part which is opposite the compartment c¹¹
with valves opening outwards. G is an induction pipe through which water is
supplied from the outside of the vessel to the compartment e', and thence to
the pumps; H is the outlet pipe through which the water is ejected at the stern
or sides of the vessel. The piston rods g¹, 9, 9, are connected forwards by
means of suitable cross-heads k¹, k, k, to three connecting rods K', K", K™,
which again are jointed to the three cranks,,, of a three-throw shaft.
The cranks, 1, 71, are placed each at an angle of 120°; so that the
engines and pumps may work with an uniform alternating motion, and the
water be thereby drawn in a continuous flow from the induction pipe G and
chamber e', and continuously discharged through the outlet pipe H. In order
that the water may be ejected equally on both sides of the rudder, the outlet
pipe II has a forked termination, as shewn in Figure 2, the two forks
discharging themselves each at the side of the rudder opposite to the other.
And in order further that the ejecting orifices may be diminished.or enlarged
according to the force and velocity with which the water is ejected, the end of
each fork is furnished with a regulating slide valve, as shewn separately on an
enlarged scale in the sectional elevation Figure 4, and plan Figure 5. A is
the slide valve; B, the slide rod, which is passed through a stuffing box and
screwed at its upper end; C is a winch handle, by the turning of which the
slide is raised or lowered. Instead of single-acting pumps as before described
being employed, double-acting may be made use of, and the other arrange-
ments modified accordingly. And instead also of using short solid pistons or
plungers, such as h', h", h, working in barrels bored to the exact size of the
pistons or plungers, long plungers may be used of less diameter than the
barrels, working through stuffing boxes, as represented in Figure 6.
The fifth and last of my said improvements consists in the mode of counter-
balancing the weight of the slides and other parts of marine engines, repre-

page_text: sented in the section and plan Figures 3 and 4, Sheet No. III., of the
Drawings hereunto annexed. A is the weigh shaft, and B the slide with its
spindle jointed to the lever C. To the opposite or outer end of the weigh
shaft there is attached a second lever or arm D. E is a small cylinder fitted
with an air-tight piston e, the rod f of which is connected by a pair of slings to
the end of the additional lever D; G is a pipe with a three-way stop-cock g,
which connects the cylinder E (below the piston) with the condenser of the
engines. To produce the desired counterpoise to the slide B, the commu-
nication between the cylinder E and the condenser is opened by turning the
cock g, which immediately produces a vacuum under the piston, and an
external pressure upon it equal to about fourteen pounds for every square
inch of the area of the piston. And when this external pressure or counter-
poise is desired to be removed, all that is necessary is to give a quarter turn of
the cock g in the opposite direction, to admit the air, and shut off the
communication with the condenser. When the engines employed are not of
the condensing sort, I make use of the elastic force of the steam as a counter-
poise to the weight of the slide, in one or other of the following modes:-
Either I employ a small covered cylinder with a packed piston, the rod of
which works through a stufling box, and admit the steam above the piston by
means of a pipe communicating from the boiler, and having a cock by which
the steam can be let on or shut off at pleasure, or, employing a cylinder and
appendages as last described, but transferring the same to the opposite side of
the weigh shaft, I admit the steam under the piston, and leave it to produce
by its upward pressure the required counterpoise. The same modes of coun-
terbalancing the weight of slides will also be found equally applicable to
counterbalancing the weight of eccentric rods, and generally wherever a
counterpoise to heavy descending weights is requisite.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I make no claim to any of
the propelling machinery herein-before wholly or in part described, except in
so far as regards the parts thereof which have been specifically pointed out as
constituting my said improvements, and which are as follows:-
First, I claim the method before described of constructing the bent cross-
head in conjunction with the forked connecting rod of direct-acting engines,
whereby the length of the connecting rod is encreased without encreasing the
height of the engine.
Second, I claim the means before described of producing the requisite
draught in the furnaces of marine steam engines, and carrying off and depu-
rating the products of combustion, whereby the ordinary funnels or chimneys

page_text: are dispensed with, and the various other advantages resulting therefrom and
before stated are obtained.
Third, I claim the aflixing between the feed pumps and boilers of marine
steam engines, of a filtering vessel constructed and operating as before
described.
Fourth, I claim, in respect of machinery for propelling vessels by the
reaction of water forced out sternwards, the working of the pistons of the
steam cylinders and water-pumps by one rod common to both, and the
regulating the ejection of the water by means of a sliding valve or valves
attached to the discharge pipe, as before described.
And, fifth, I claim the employment in manner before described of the forces
of atmospheric pressure and steam pressure to counterpoise the weight of the
slides, eccentric rods, and other parts of marine steam engines requiring to
be counterpoised, and whether the same are used separately or conjointly for
that purpose.
In witness whereof, I, the said John Seaward, have hereunto set my
hand and seal, this First day of August, in the year of our Lord One
thousand eight hundred and forty-five.