IMPROVEMENTS IN APPARATUS FOR PROPELLING VESSELS
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents, with his Petition, on the
23rd January 1874.-A communication from abroad by John
Sketchley Morton, of Philadelphia, County of Philadelphia, and
State of Pennsylvania, United States of America.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN APPARATUS FOR PROPELLING VESSELS,"
to be as follows:-
This Invention relates to improvements in propellers for navigable
vessels, by which paddle wheels, or screws, also pistons, piston rods,
cranks, and walking beams are dispensed with, and steam and water are
brought in direct contact in suitably arranged cylinders or chambers,
having openings at their lower ends, through which the water is
alternately admitted and expelled by the corresponding alternate steam
pressure and vacuum therein, the rapidity of propulsion being directly
dependent (other things equal) on the rapidity of the in and out flow

page_text: Each leg has an opening one on the front and the other on the rear
side, so that the vessel may be propelled in either direction according to
the position of the slide valves, which are arranged to close the entrance
to one leg when the other is open, and vice versa.
The valves are operated by rods sliding horizontally in suitable stuffing
boxes, and by hand levers pivoted to said rods and having suitable
fulcra exteriorly of the cylinders, by the side of which they extend
upward, so as to be convenient of access to the engineer or other person
in charge of the propelling apparatus.
The aforesaid openings in the legs of the cylinders may be left free or
covered with a removable grating formed of a frame provided with cross
bars. One of the objects of the same is to prevent admission of
comparatively large pieces of wood, timber, ice, or other floating objects,
whose rapid entrance and ejection might effect an injury to the cylinders.
I also conceive advantage may be derived from the use of the grating
over and above the slight obstruction the bars necessarily offer to the in
and out flow of the water, from the fact that a number of streams of
water (or other fluid) when injected into a body of water (or other fluid)
penetrate said body to a shorter distance than they would if combined in
a single stream. Hence the effect of a divided stream of water from the
cylinders would be less injurious to the banks of a canal than a single
stream penetrating further. It is also probable that other advantages
are incidental to the use of the gratings, but it is unnecessary to detail
them here.
I intend to provide a series of removable plates with orifices of various
sizes and forms, and also a series of gratings with different sized bars or
openings, so that I may attach such an one as conditions indicate or
require at different times. The means of attachment may be screw bolts
or other suitable devices.
The steam generator is connected with the steam and water cylinders
by means of a pipe which divides in two branches, each leading to a
steam chest. From the steam chest a pipe leads downward into each
cylinder a short distance below the top thereof. Such extension within
the cylinders is perforated on the sides and closed at the end, so that the
steam on entering the cylinders will be caused to diverge laterally in
numerous jets or currents, mingling with and expanding the air above
the lower or closed end of said pipe, and be diffused over the stratum of

page_text: air over the water below, thus causing it to act uniformly on the water
in place of plunging vertically downward as one stream or current into
the water, as would happen if the pipes were open at the end and
imperforate on the sides.
An open ended pipe leads from the combustion chamber of the
generator furnace, and is bifurcated like the steam pipe, each branch
entering one of the propeller cylinders or chambers and terminating in
the upper third thereof. The function of this pipe is to convey from the
furnace a portion of the highly heated air or the gases produced by
combustion, and deliver the same in the cylinders as the vacuum is 1
created and the cold or atmospheric air and water are entering. To
provide for such admission of the cold or outer air short tubes are
attached to and communicate with the upper end of the cylinders, the
same curving downward to facilitate the closing of the poppet valves on
their seats by aid of gravity. Each valve has a guide and screw stem 1
on which is placed a nut. By adjusting the nut the play of the valve
will be regulated or limited at pleasure, and thereby also the amount of
atmospheric air admitted to the cylinder in a given time.
The floats disposed within the steam and water cylinders for operating
the steam valves are preferably round or oval in form, and are bored 2
longitudinally to adapt them to slide on vertical rods or bars, which
extend up through the upper heads of the cylinders and into the valve
chests, where they connect with and operate steam valves. The valve
rods have slight vertical play to lift the valves off their seats, and allow
the admission of steam to the cylinders. This vertical movement is 2
caused by the movement of the floats. In rising, the latter comes in
contact with stop blocks, which are made adjustable on the rods by
means of clamp screws, and in falling, as the water is forced out by steam
pressure, their movement is arrested by corresponding stops near the
lower end of the rods. By placing and securing these blocks higher or s
lower, i.e., further apart or nearer one another on the valve rods, it is
apparent the time during which the valves will be held open will be
correspondingly increased or diminished, and hence also the time during
which the steam pressure and succeeding vacuum will exist, and hence
again the height and quantity of water in the cylinders at any time. It a
is not however designed that the water shall in any case be allowed to
rise quite to the lower end of the perforated steam induction pipes.
.

page_text: It is necessary to the production of the best effect, that they
should have no other weight to raise than that due to the friction of
the rods in their stuffing boxes, also that a means should be provided
for raising the valves when it is desired to put the propelling apparatus
in action. To this end I employ levers which are pivoted centrall
to fulcrum posts in the top of the cylinders, and also. at one end to the
valve rods. Their free ends are screw threaded and have balls or
weights applied thereto, which may be adjusted to exactly weigh or
counterbalance the weight of the rods and valves.
The admission of steam to the chests is controlled by a throttle valve,
but the valves located in the bifurcations of the hot air tube are
arranged both for automatic action as check valves and for positive
control. For this purpose the stem which screws through the nut has a
tube or sleeve attached to its inner end, and in this the stem of the
valve plays. Hence, when the vacuum is created in the cylinders the
valves will rise and allow hot air to pass over from the furnace, but
when the vacuum ceases and steam is admitted the valves will again
close on their seats. When it is desired to entirely prevent the
admission of hot air to the cylinders, the stem is screwed down, thus
causing the sleeve or tube to hold the valve on its seat.
The valves in the steam chest are of disc form and secured on the
valve rods at the same distance apart as the diameter of the steam pipe
or valve seat, being formed in or on each side of the pipe.
The operation of the propelling apparatus is as follows:- Steam being
generated to a suitable pressure in the boiler, and the valves of one
steam chest raised from their seats by the aid of the starting lever
belonging thereto and the throttle valve raised, steam will enter and fill
the cylinder and expel whatever quantity of water may be therein. As
the water falls into the cylinder its float follows by effect of gravity
until it strikes against the stop block and hence closes the valves on
their seat. The steam escapes mainly with the air and water and partly
condenses also, thus creating a vacuum in the cylinder which the water
instantly seeks to fill. Simultaneously with the creation of the vacuum
the valves for admitting cold and hot air open automatically the air
commingling in the cylinder. When the water has risen sufficiently
high to cause the float to strike against the stop block and to raise the
valves anew the steam again enters, and being somewhat expanded by

page_text: the more highly heated air their combined expansive force causes the
ejectment of the water. The operation of one cylinder and its connected
apparatus is identical with the other, and being alternate, in time a
stream is constantly forced into the floatative body of water, thus
causing a constant propulsive effect on the vessel.
In place of forming separate legs for each cylinder, the diaphragm or
partition may be dispensed with, and a gate provided which shall close
one of the openings and open the other, according as it is desired to
propel the vessel forward or backward. Also other arrangements of
levers may be made for working the water valves, which would operate
with equal facility with those shown in the Drawings.
When preferred or for any reason necessary the cylinders may also be
located near (or nearer) the middle of the boat or vessel, and have water
passages leading outward and downward toward the bow and stern.
Other means of adjusting the weights on the valve levers may also be
employed, and there may be two sets of levers separate and distinct from
each other, one set for counterbalancing the weights of the valves and
valve rods, the other for adjusting the valves.
Other forms of valves might be likewise adopted than those here
shown and with equally good effects. Also by a proper arrangement of a
valves the water may be received into the cylinder or chamber through
one orifice and ejected from another orifice, or two cylinders or chambers
may be so connected as to alternately receive the water through a
common orifice, and which may be ejected alternately from the cylinders
through another common orifice, so that one cylinder or chamber would 2
fill with water by atmospheric pressure, while the corresponding one
would be emptying, and, vice versa, but preferably I arrange the
cylinders or chambers independently of each other, and receive and
eject the water through the same orifice in each cylinder or chamber
respectively.
In a modification of the apparatus the steam and water cylinders have
induction and discharge orifices opening rearward, and air check valves
applied at the side and near the top. The steam chest and cylinders are
connected by pipes, and valves are arranged to work in guides in said
chest so as to alternately cover and uncover the mouth of said pipes, a
and thus control the admission of steam to the cylinders. Small

page_text: cylinders containing floats communicate at each end with the large
cylinders by small tubes. A float works in each of these small cylinders
and has a headed stem which works in a stirrup that is attached to the
lower end of the stem of valve.
It is evident that the rise and fall of each float and thereby the like
movement of the valves connected with them, will correspond with the
rise and fall of the water within the large cylinders, since the height of
water in them will be always the same as in the small cylinders.
It should be stated that if the water is admitted into the cylinder
only to a height corresponding to the general level externally, the
cylinder should extend at least six inches above that level, but if the
full atmospheric pressure is to be utilized the cylinder requires to be
extended about twenty-six feet higher.
I have demonstrated satisfactorily that the plan generally much
commended of taking water from the bow of the vessel secures no
advantage, besides the tubes necessary to conduct the water backward to
the vacuum chamber occupy valuable space, and because of their length
add largely to friction, and obstruction or injury is likely to occur from
encountering (or taking in) floating or fixed objects. By admission and
expulsion of water through a single orifice not only these results are
avoided, but advantages are superadded in several ways. But while
such is the fact I do not desire to limit the Invention (otherwise than is
herein set forth or indicated) exclusively to propellers, in which water
is taken in and discharged at the stern only since the apparatus is
(mainly) available in either case.