IMPROVEMENTS IN AND CONNECTED WITH MARINE AND OTHER STEAM ENGINES
Year: 1860

page_text: LETTERS PATENT to William Macnab, of Greenock, in the County of
Renfrew, North Britain, Engineer, for the Invention of "IMPROVEMENTS
IN AND CONNECTED WITH MARINE AND OTHER STEAM ENGINES.”
Sealed the 15th June 1860, and dated the 21st April 1860.
PROVISIONAL SPECIFICATION left. by the said William Macnab at the
Office of the Commissioners of Patents, with his Petition, on the 21st
April 1860...
I, WILLIAM MACNAB, of Greenock, in the County of Renfrew, North
Britain, Engineer, do hereby declare the nature of the said Invention of
"IMPROVEMENTS IN AND CONNECTED WITH MARINE AND OTHER STEAK ENGINES," to be
as follows, that is to say:-.
This Invention comprehends various improvements in and connected with
steam engines,having principally for object the beneficial development of the
system of surface condensation' in 'marine engines, although also in part appli-
cable otherwise.
The first part of the Invention relates to a design for the arrangement of
the parts of marine engines of the oscillating class for driving paddle wheels
or screw propellers either direct or through gearing. In this design the
Грайм 911

page_text: oscillating cylinders and various other parts are placed within a rectangular
base or space, the surface condenser being placed at one side of this base.
The cylinders occupy the opposite ends of the rectangular space, having
between them the air pumps and the pumps for forcing the condensing sea
water through the condenser. The base plate or casting occupying the floor
of the rectangular space is formed with seats for the pumps, and passages to
and from them,also with the usual bearings for the cylinder trunnions, both
cylinders exhausting through their inside trunnions or bearings into a single
passage leading over with a bend to the condenser. The parts are so arranged
that the surface condenser can be converted into. an ordinary condenser, or be
removed and an ordinary one substituted.
The air and sea water current pumps may be worked in various ways, but
it is preferred to employ eccentrics placed on the intermediate shaft, and
connected to levers or beams which communicate the motion to the pump
rods. The pumps may be double acting or single acting as preferred,and their
number may also be varied. The condenser may be constructed with the tubes
arranged either in a horizontal or vertical position, and the sea or condensing
water may be made to pass through or inside of these tubes by means of
pumps or other suitable apparatus, being made to flow alternately in opposite
directions by means of partitions. The currents also from the 1
pumps may be
kept separate, and made to cross each other by a suitable arrangement of the
passages and partitions.
According to the second portion of the Invention it is purposed to fix the
ends of the tubes into small frames in sets of six, seven, or any convenient
small number in each frame,the frames being either square,round, or of other
suitable form. Anumber of these sets of tubes are placed inside the condenser
and the frames into which their ends are fixed are made to pass through
openings of a corresponding form made in the ends of the-condenser, and
secured with any suitable elastic or other packing, and with or without glands
at one or both ends,so that the frames into which the tubes are fastened may
have free liberty to move in the end plate of the condenser with the expansion
and contraction of the tubes by change of temperature,and at the same time
form a perfect joint.
.
A number of the setsof tubes such as have been described 1 may be arranged
across the part of the condenser at which the steam enters, or across the
exhaust passage or pipe, and through these tubes the water of condensation
may be made.to pass on its way to the boiler, so as to take up. and utilise
some of the heat of the steam about to be condensed. This arrangement is

page_text: very conveniently applicable to inverted cylinder engines, such as are used
for driving the screw-propeller.
According to the third portion of this Invention an apparatus is provided
for evaporating sea water to be distilled or condensed for making up the
waste and leakage occurring in the main boiler, engine, and condenser, and at
the same time to provide fresh water for various uses on board the vessel,such
as cooking and washing. To this end an auxiliary boiler or boilers of simple
and efficient construction is used to effect the evaporation of the sea water at
a low pressure,and the steam thus produced is elevated to a high temperature
by means of superheating apparatus in connection with the auxiliary boiler or
boilers; the steam so generated and superheated being then passed through
the jackets surrounding the cylinders, valve casing, and other parts of the
engine previous to passing to the distilling apparatus. In this way the
advantage of encompassing the cylinders, valve casings, and other parts with
jackets supplied with steam of low pressure, and a high temperature can be
obtained with an auxiliary boiler or boilers of a simple, light, and efficient
construction, whilst a great portion of the heat required for evaporating the
sea water is thus utilised in the jackets. The sea water to be evaporated may
be taken from that which has passed through the condenser, thereby utilising
the heat it takes up in the condenser.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Macnab in the Great Seal Patent Office on the
19th October 1860..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
MACNAB, of Greenock, in the County of Renfrew, North Britain, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of April, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Macnab, Her special licence that I, the said William
Macnab, my executors, administrators, and assigns, or such others as I, the
said William Macnab, my 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

page_text: upon the
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Mau, an Invention for "IMPROVE-
MENTS IN AND CONNECTED WITH MARINE AND OTHER STEAM ENGINES,"
condition (amongst others) that I, the said William Macnab, my executors
or administrators, by an instrument in writing under my, or their, or one
of their hands and seals, 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 mouths next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said William Macnab, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to say :-
My said Invention comprehends various improvements in and connected
with steam engines, having principally for object the beneficial develop-
ment of the system of surface condensation in marine engines, although
also in part applicable otherwise.
And in order that the same may be properly understood and carried into
effect, I have hereunto appended a Sheet of explanatory Drawings, to which
I shall refer in particularly describing the said improvements, as follows:-
The first part of my said Invention relates to a design for the arrange-
ment of the parts of marine engines of the oscillating class, for driving
paddle wheels or screw propellers either direct or through gearing.
Figures 1, 2, and 3 on the Sheet of Drawings represent a pair of paddle-
wheel engines as arranged according to this design, Figure 1 being a vertical
section taken longitudinally as regards the vessel, partly as along the line 1-1
and partly as along the line 2-2, Figure 3; whilst Figure 2 is in part a
transverse vertical section, taken as along the line 3-3 in Figure 3, and in
part a front elevation of one half of the arrangement; and Figure 3 is a
sectional plan(with the outside halves of the cylinders removed to contract the
Figure). In this design the oscillating cylinders A and various other parts
are placed within a rectangular base B or space,the surface condenser Cbeing
placed at one side of this base. The cylinders A occupy the opposite ends of
the rectangular space, having between them the air pump D and the two
pumps E, E, for forcing the condensing water through the condenser C. The
base plate or castings Boccupying the floor of the rectangular space is formed

page_text: with seats for the pumps D, E, E, and passages to and from them, namely,
the passaged from the middle of the condenser bottom C to the air pump D,
and the hot well d', or passage from the air pump; also the passages e, e, by
which the sea water enters the current pumps E, E, and the passages e¹, e¹,
from these pumps to the condenser C. The base plate B is also provided
with the usual bearings F for the cylinder trunnions, a, a, both cylinders
exhausting through their inside trunnions a¹or bearings into a single passage
G, leading over with a bend to the condenser C. The parts are so arranged
that the surface condenser may be converted into an ordinary condenser, or be
removed and an ordinary one substituted.
The air and sea water current pumps D, E, E, may be worked in various
ways, but it is preferred to communicate the motion to the pump rods by
means of levers or beams actuated from the intermediate shaft H by an
eccentric or crank. The pumps may be double-acting or single-acting, as
preferred, and their number may also be varied. In the example represented
in the Drawings the pumps are single-acting, and are all worked from a pair
of parallel levers I fast on a rocking shaft i. The current pumps E are
worked by rods jointed upon separate pins ², one on each lever I, a single pin
or cross bar i², fixed in both levers working the air pump D, whilst a single
pin or cross bar ³, also fixed in both levers, has jointed to it the rod from the
crank or eccentric h, from which the motion is derived.
The condenser may be constructed with the tubes arranged either in a hori_
zontal or vertical position, and the sea or condensing water may be made to
pass through or inside of these tubes, by means of pumps or other suitable
apparatus, being made to flow alternately in opposite direction's by means
of partitions. The currents also from the pumps may be kept separate, and
made to cross each other, by a suitable arrangement of the passages or par-
titions.
In the modification of condenser represented in the Drawings, the tubes K
are arranged horizontally, being held in tube plates L bolted to the casting,
forming the body C of the condenser. The tube plate castings are formed
with flanged sides to receive the covers M enclosing spaces for the access of
the water to the tubes, these spaces being divided by partitions 7, in such a
way as to cause the water currents to take the directions indicated by the
arrows. The tubes K (shown in Figures 2 and 3), are arranged' with intervals
separating them into two vertical sets of three tiers each. The current from
one pump E traverses the tubes in the lowest tier of one set in one direction
the other lowest tier of tubes being traversed in the opposite direction by the

page_text: current from the other pump E. The currents are reversed in the middle
and again in the upper tiers, still, however, going in opposite directions as
regards each other, and finally leave the condenser at the top by the exit
passages N. The entrance passages e¹ are extended upwards to act as air
vessels.
According to the second portion of my said Invention I fix the ends of con-
denser tubes into small frames in sets of six, seven, or any convenient small
number in each frame, the frames being either square, round, or of other
suitable form. A number of condenser tubes K arranged in this way are
represented on an enlarged scale in plan or longitudinal section in Figure 4,and
in end elevation in Figure 5. Anumber of these sets of tubes are placed inside
the condenser and the frames k, k¹, into which their ends are fixed by
screwing, soldering, or otherwise, are inserted in openings of a corresponding
form made in the tube plates L. The frames may be screwed or held in the
tube plates with suitable elastic or other packing, and with or without glands
at one or both ends, so that the frames may have liberty to move in the tube
plate or plates with the expansion and contraction of the tubes by change of
temperature, and at the same time form a perfect joint. As represented in
the Drawing, the small tube frames k, at one end are formed with external
flanges, beneath which rings of elastic material, such as caoutchouc, are
introduced. The frames are fixed by screw bolts ',.arranged as shown in
Figure 5. The frames k³ at the other end are made without flanges, but are
encircled externally by rings k², beneath which are elastic packing rings, the
rings k² being held by screw bolts 1, in the manner shown in Figure 5. In this
manner provision is made at this end for the elongation and contraction of the
tubes, and consequent movement of the frames . A number of the sets of
tubes such as have been described may be arranged across the part of a con-
denser at which the steam enters, or across the exhaust passage or pipe, and
through these tubes the water of condensation may be made to pass on its way
to the boiler, so as to take up and utilise some of the heat of the steam about
to becondensed. This arrangement is very conveniently applicable to inverted
cylinder engines, such as are used for driving the screw propeller.
k2
According to the third portion of my said Invention an apparatus is pro
vided for evaporating sea water to be distilled or condensed for making up
the waste and leakage occurring in the main boiler, engines, and condenser,
and at the same time provide fresh water for various uses on board the vessel,
such as cooking, washing, &c. To this end an auxiliary boiler or boilers of
simple and efficient construction is or are used to effect the evaporation of the

page_text: sea water at a low pressure, and the steam thus produced is elevated to a
high temperature by means of arrangements for superheating it. in connec
tion with the auxiliary boiler.or boilers, the. steam so generated and super-
heated being then passed into the jackets surrounding the cylinders, valve
casings, and, other parts of the engines previously to passing to the distilling
or condensing apparatus. In this way the advantage of encompassing the
various parts of the engines with jackets supplied with steam of low pressure,
but high temperature, can be obtained with an auxiliary boiler or boilers of
a simple, light, and efficient construction, whilst a great portion of the heat
required for evaporating the sea water is thus utilised in the jackets. The
sea water to be evaporated may be taken from that which has passed
through the condenser, thereby utilising the heat it has taken up in
the condenser.
Without restricting myself to any particular form or construction of
auxiliary boiler,. I have represented a suitable modification in Figures 6, 7,
and 8 on the accompanying Sheet of Drawings, Figure 6 being a front
elevation, and Figures 7 and 8 vertical sections at right angles to each other.
In this boiler the fire gases enter from the furnace A into a single flue opening
B immediately communicating with two divergent flues C, which again
converge at D, and reunite in a single flue E passing out of the boiler.
The convergent parts D of the flues are above the water line, and are
crossed by tubes to increase the surface exposed to the heat, for the purpose
of superheating the steam. A flue door F is provided to give access for
cleaning the tubes externally, other man-hole doors being also provided for
access to the internal parts of the boiler.
Having thus particularly described my said Invention, and the manner
in which the same is or may be used or carried into effect, I have to state
that I do not restrict myself to the precise details herein-before described
or delineated; but that what I consider to be novel and original, and claim
as the Invention secured to me by the herein-before in part recited Letters
Patent, is,―
First, the arranging or combining together of the parts of oscillating
engines, substantially as herein-before described.
Second, the arranging of the surface condensers and the passages apper-
taining thereto, substantially as herein-before described.
Third, the constructing of the tubular portion of a surface condenser,
substantially as herein-before described, that is to say, with small frames,
into each of which a convenient small number of tubes are fixed, being
held in the tube plates by means of the frames.

page_text: Fourth, the evaporating of sea water at a low pressure and superheating.
of its steam for use in the jackets of the engines, and to be subsequently
condensed to supply water for waste and leakage, and for other purposes,
substantially as herein-before described.
In witness whereof, I, the said William Macnab, have hereunto set my
hand and seal, this Eighteenth day of October, in the year of our
Lord One thousand eight hundred and sixty.
Witness,
EDMUND HUNT, Patent Agent,
28, St. Enoch Square,
Glasgow.
WILLIAM MACNAB. (L.B.)