IMPROVEMENTS IN STEAM ENGINES FOR SCREW PROPUL- SION AND OTHER MOTIVE PURPOSES."
Year: 1877

page_text: LETTERS PATENT to Robert Steele, junior, Shipbuilder, and William Lynde
Brunton, Engineer, both of Greenock, in the County of Renfrew, North Britain,
for the Invention of "IMPROVEMENTS IN STEAM ENGINES FOR SCREW PROPUL-
SION AND OTHER MOTIVE PURPOSES."
PROVISIONAL SPECIFICATION left by the said Robert Steele and William
Lynde Brunton, at the Office of the Commissioners of Patents on the 23rd
February 1877.
ROBERT STEELE, junior, Shipbuilder, and WILLIAM LYNDE BRUNTON, Engineer,
both of Greenock, in the County of Renfrew, North Britain. "IMPROVEMENTS IN
STEAM ENGINES FOR SCREW PROPULSION AND OTHER MOTIVE PURPOSES."
This Invention consists in an improved arrangement or combination of the parts
of steam engines designed for driving the screw propeller, but also advantageously
applicable for other motive purposes.
In one modification of the improved arrangement or combination, the engines are
compound, and the high-pressure cylinder and the low-pressure cylinder are placed
vertically on opposite sides of the main shaft, which has on it a single crank. Two
transverse bed frames, provided with bearings for the crank shaft, connect the lower
parts of the cylinders; and the after one of these frames is made in the same casting
with the shell of a surface condenser placed transversely over the shaft.
In large engines the condenser shell may be in a separate casting or castings.
What may be termed a forward upper frame piece connects the upper parts of the
cylinders above the shaft, and the whole framing and cylinders form a strong and
rigid structure.
The piston rods have blocks fixed to them, and sliding on bracket guides fixed
to the tops of the cylinders, and the blocks are connected by short links to an open
triangular piece forming what may be termed a combined lever connector. This
combined lever connector resembles in form the combination of the diagonal and two
sides of a square, the corner or junction of the two sides being downwards and
jointed on the crank of the main shaft, and the extremities of the diagonal being
connected, one to the high-pressure piston rod slide block, and the other to that of
the low-pressure piston rod; whilst at the middle of the diagonal, a pin projecting on

page_text: each side is fitted with slide blocks working in two pairs of vertical guides formed,
one pair in the forward upper frame piece, and the other pair formed or fixed upon
the condenser shell. With this arrangement the two cylinders act on the single
crank in a manner similar to, but in some respects better than that of the common
arrangement in which two cylinders act on cranks at right angles to each other.
The improved arrangement, so far as herein-before described, admits of the minor
or necessary details of the engines being placed and connected in a very simple and
practically convenient manner. Thus two single eccentrics serve for working the
valves of both cylinders, separate pairs of rods from the eccentrics being connected
to valve motion links acting directly on bell-crank levers or rocking shafts upon
the tops of the valve casings. The air pump is placed vertically against the inner
side of the high-pressure cylinder, and the circulating or cold water pump is placed
vertically against the inner side of the low-pressure cylinder, and the two pumps
are worked directly from the combined lever connector.
In other modifications the two cylinders may be arranged to work as non-com-
pound, and two or more cylinders may be placed at each side.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert 'Steele and William Lynde Brunton in the Great Seal Patent
Office on the 18th August 1877.
ROBERT STEELE, junior, Shipbuilder, and WILLIAM LYNDE BRUNTON, Engineer,
both of Greenock, in the County of Renfrew, North Britain. "IMPROVEMENTS IN
STEAM ENGINES FOR SCREW PROPULSION AND OTHER MOTIVE PURPOSES."
Our said Invention consists in an improved arrangement or combination of the
parts of steam engines designed for driving the screw propeller, but also advan-
tageously applicable for other motive purposes.
In one modification of our improved arrangement or combination, the engines are
compound, and the high-pressure cylinder and the low-pressure cylinder are placed
vertically on opposite sides of the main shaft, which has on it a singlo crank. Two
transverse bed frames provided with bearings for the crank shaft, connect the lower
parts of the cylinders, and the after one of these frames is in some cases inade in the
same casting with the shell of a surface condenser placed transversely over the
shaft.
In large engines, and also if preferred in other cases, the condenser shell may be
in a separate casting or castings; and in such cases the two bearings of the crank
shaft may be in a single bed frame connecting the two cylinders.
The piston rods are connected to an open triangular piece forming what may be
termed a combined lever connector, which resembles in form the combination of the
diagonal and two sides of a square, the corner or junction of the two sides being
downwards and jointed on the crank of the main shaft, and the extremities of the
diagonal being connected, one to the high-pressure piston rod, and the other to the
low-pressure piston rod; whilst at the middle of the diagonal, a pin projecting on
each side is fitted with slide blocks working in two pairs of vertical guides formed,
one pair in a forward upper frame piece connecting the cylinders, and the other pair
formed or fixed on the condenser shell. With this arrangement the two cylinders
act on the single crank in a manner similar to, but in some respects better than
that of the common arrangement in which two cylinders act on cranks at right
angles to each other.
Our improved arrangement so far as herein-before described, admits of the minor
or accessory details of the engines being placed and connected in a very simple and
practically convenient manner. Thus two single eccentrics serve for working the
valves of both cylinders, whilst the air pump is placed vertically against the inner
side of one cylinder and the circulating or cold water pump against the inner side

page_text: of the other cylinder, and the two pumps are worked directly from the combined
lever connector.
In other modifications the two cylinders may be arranged to work as non-com-
pound, and two or more cylinders may be placed at each side, whilst in some cases
the crank shaft may be placed higher than the cylinders, the combined lever con-
nector being inverted.
And in order that our said Invention and the manner of performing the same
may be properly understood, we hereunto append two Sheets of explanatory
Drawings, to be herein-after referred to, and representing modifications of our
improved arrangement of engines suitable for driving the screw propeller. In these
Drawings the same reference numerals are used to mark the same or like parts
wherever they are repeated.
Figure 1, on Sheet 1 of the accompanying Drawings, is a forward side or front
elevation, and Figures 2 and 3, on Sheet 2, are respectively a fore-and-aft vertical.
section and a plan corresponding to Figure 1.
In this arrangement of engines a high-pressure cylinder 1 and a low-pressure
cylinder 2 are placed vertically on opposite sides of the crank shaft 3, and are con-
nected to each other by a rectangular bed frame 4 having bearings 5, 6, for the
crank shaft 3, and a. middle opening for the crank 7, the shaft being made with
only one crank. What may be termed a forward upper frame piece 8 connects the
upper forward parts of the cylinders 1, 2, above the shaft 3, and at the after part
there is an arched casting 9, 10, 11, comprising the shell 10 of a surface condenser,.
and an upper part 11 like the upper part of the forward frame piece 8, the casting
being bolted to the cylinders 1, 2, and to the bed frame 4. The whole framing and
cylinders thus forn a strong and rigid structure. The piston rods 12, 13, of the
cylinders 1, 2, have blocks 14, 15, fixed to them and fitted to slide on bracket'
guides 16, 17, fixed to the tops of the cylinders, and the blocks 14, 15, are con-
nected by short links 18, 19, to the open triangular piece or combined lever con-
nector 20, 21, 22, 23. The upper member 20 of this piece consists of two bars, and
is the diagonal of a square, of which the lateral members 21, 22, form the sides.
The upper ends of the lateral members 21, 22, are placed between the ends of the
bars 20 forming the upper member, to which they are attached by pins extending
on either side to receive the links 18, 19. A fourth member 23 extends from the
middle of the upper or diagonal member 20 down towards the corner formed by the
lateral members 21, 22, where the three members 21, 22, 23, are united in a
block 24, which is fitted with bearing brasses on the crank 7, in a manner that will
be easily understood from the Drawing. The upper end of the fourth member 23
of the connector is entered up between the bars of the upper member 20, and a long
pin 25 is passed through the three pieces, the ends of the pin 25 projecting on each
side into bearings in blocks 26 fitted to slide between guides 27, 28. One pair 27,
of these guides are formed on the forward upper frame piece 8, and the other
pair 28 on the upper part 11 of the after casting, and partly on the forward side of
the condenser shell 10. The bearing brasses for the pin 25 in the blocks 26 are
fitted to the blocks with inclined surfaces admitting of their being tightened on the.
pin by vertical adjustment.
The combined and relative movements of the parts, will be easily understood if
the combined lever connector 20, 21, 22, 23, is supposed to follow the circular
motion of the crank with its lower part, whilst the centre (25) of its upper
member 20 is by the guides 27, 28, constrained to move vertically. It will on
consideration of such movement be found that the outer extremities of the upper
member 20 reciprocate in nearly vertical paths in such a corelated way that when
one is at the middle of its stroke. the other is at the end of its stroke. It thus
follows that the pistons of the cylinders 1, 2, necessarily moving in concert with the
combined lever connector, have the same relative movements or nearly so as two
pistons in ordinary arrangements acting on cranks at right angles to each other.
It will also be found on consideration of the relative positions and directions of
motion of the parts at different points of the revolution of the crank that the

page_text: leverages and strains and general actions are more favorable for efficient work with
little friction than in many existing types of engine. Thus when either piston is
at what is commonly termed its dead centre it has more tendency to turn the crank
than is the case in many other arrangements, which is an important advantage, par-
ticularly when starting or working slowly.
A single pair of eccentrics 29 serves for working the valves of both cylinders, the
strap of each eccentric having two rods 30, 31, attached or jointed to it, which are
connected in pairs to motion links 32, 33. From these links 32, 33, the movements
are communicated to the respective valve rods 34, 35, by bell-crank levers 36, 37,
and links, and the links 32, 33, may both be reversed or adjusted by a single lever
or rocking shaft placed centrally above the crank shaft, and having rods. from
opposite sides of its fulcrum connecting it to the links.
The reversing lever is not shown in the Drawings, but its arrangement and action
will be easily understood.
The air pump 38 is placed between the high-pressure cylinder and the crank
shaft 3, and the cold water or circulating pump 39 is placed between the low-
pressure cylinder and the crank shaft. The piston rods of the two pumps 38, 39,
are attached to slide blocks 40, 41, working in guides formed or fixed on the forward
side of the condenser shell 10, and connected by links 42, 43, to one of the upper
bars 20 of the combined lever connector.
Steam has access to the high-pressure cylinder 1 by a pipe 44, and passes from
the exhaust space of the valve casing of that cylinder by a pipe 45, which crosses
under the crank shaft 3 to the valve casing of the low-pressure cylinder 2, the
exhaust from which passes through a hollow belt round the cylinder, and thence by
a pipe 46 to the condenser.
Any minor details not herein-before referred to or not shown in the accompanying
Drawings may be arranged as in existing engines, their adaptations to our improved
engines presenting no difficulty.
Instead of the piston rods 12, 13, being connected to the combined lever con-
nector by links 18, 19, the pistons may be fitted with trunks and be directly con-
nected by long links or jointed rods to the connector, no external guides being in
that case required. Such trunks can be made comparatively small, as the lateral
movement of the ends of the connector bars 20 is very little.
+
Having thus particularly described our said Invention and the manner of per-
forming the same, we have to state that we do not restrict ourselves to the precise
details herein described or delineated, but that what we believe to be novel and
original and claim as the Invention secured to us by the herein-before in part
recited Letters Patent is,-
1. The arranging or combining together of parts to form a steam engine with two
or more cylinders, in the improved manner herein described or delineated.
2. The herein-before described mode of placing the surface condenser, and com-
bining it with the other parts of the engines.
3. The placing of the air and circulating pumps to the inner side of the steam
cylinders, and working them directly from the combined lever connector, as herein-
before described.
In witness whereof, I, the said William Lynde Brunton, on behalf of the said
Robert Steele, junior, and myself, have hereunto set my hand and seal, this
Sixteenth day of August, in the year of our Lord One thousand eight
· hundred and seventy-seven.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
WILLIAM L. BRUNTON. (L.S.)