Improvements in Steam Engines.
Year: 1889

page_text: Date of Application, 30th May, 1889
Complete Specification Left, 20th Aug., 1889-Accepted, 12th Oct., 1889
PROVISIONAL SPECIFICATION.
Improvements in Steam Engines.
I ANDREW LECKIE of Cambridge Terrace West Hartlepool in the County of
Durham Engineer do hereby declare the nature of this Invention to be as follows:-
My Invention relates inore especially to marine steam engines.
According to my Invention I provide in combination with the cylinders of the
ordinary compound engines a second high pressure cylinder both of the high pressure
cylinders receiving steam direct from the Steam Boiler or Boilers either by a separate
pipe or passage or by a branch from the same pipe.
The steam may be admitted from one Slide valve casing common to both High
pressure cylinders or by slide valves for each cylinder.
This second High pressure cylinder may be made of such capacity that it will admit
of the introduction when desired of a liner or filling (and a corresponding piston) for
instance when there is an increased Boiler Pressure when a new Boiler is or new
Boilers are put in when the Exhaust from the second high pressure cylinder may be
passed into the original High pressure cylinder instead of into the low pressure
cylinder the engine then working as a triple expansion engine. The second high
pressure cylinder I prefer shall have such a diameter as to permit of the said cylinder
receiving a liner of such size as to permit of the cylinder itself constituting a jacket
the liner reducing the internal size of the cylinder to be suitable for preventing undue
strain on the engines due to the pressure in the new Boiler or Boilers.
This second high pressure cylinder may be set in any position relatively to the
other high pressure and low pressure cylinders but its piston works on a separate
crank which may be set at an equidistant angle from the two others or the three cranks
may be arranged at 120° apart or at such intermediate angle as to best equalize the
strain and balance the pistons rods and cranks.
By this arrangement I permit a greater degree of expansion being used on the two
High pressure pistons so that there will be a large reduction in the quantity of steam
used for the power developed and a much more steady motion of the engine than in the
ordinary compound Engine.
The second high pressure cylinder may be formed with two exhaust branches or
Ports so that a connexion may be formed with either the low pressure valve casing or
with the valve casing of the other high pressure cylinder according to the way the
engines are to be used that is to say either so that both High pressure cylinders will
exhaust into the Low pressure slide valve casing or into the intermediate cylinder valve
casing when so required which is effected by connecting a new exhaust pipe.
The arrangement of pipes may be varied to meet the constructions of the engines to
which this invention is applied.
By this invention a portion of the benefits derived from triple Expansion Engines
will be obtained without expense of condemning a Boiler or Boilers which has
or have several years wear while the extra cost when boilers are worn out will be
comparatively light.
Dated this 30th day of May
1000
.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Steam Engines.
I ANDREW LECKIE of Cambridge Terrace West Hartlepool in the County of
Durham Engineer do hereby declare the nature of this Invention and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement :-
My Invention relates more especially to marine steam engines but is not restricted
thereto.
According to my Invention I provide in combination with the cylinders of the
ordinary compound engines an additional high pressure cylinder both of the high
pressure cylinders receiving steam direct from the steam boiler or boilers either by a
separate pipe or passage or by a branch from the same pipe and both cylinders
exhausting into the slide valve casing of the low pressure cylinder. The two high
pressure cylinders may be supplied with steam from one slide valve casing common to
both cylinders or each cylinder may have a slide valve casing of its own.
The said
The additional high pressure cylinder may or may not at first be provided with a
liner capable of being removed when desired. Where such liner is inserted the space
between it and the cylinder walls is suited for use as a steam jacket.
additional cylinder may afterwards be lined with or have the original liner replaced
by a liner of smaller diameter and be supplied with a corresponding piston so as to
convert the engine into a triple expansion engine, for instance when a new boiler is
or new boilers are to be employed and increased boiler pressure is to be used, the
exhaust from the additional high pressure cylinder being then passed into the original
high pressure cylinder slide valve casing instead of direct into the low pressure
cylinder slide valve casing, the engine then working as a triple expansion engine.
The additional high pressure cylinder may be set in any position relatively to the
other high pressure and low pressure cylinders but its piston works on a separate crank
which may be set at an equidistant angle from the two other cranks worked by the
pistons of the other cylinders respectively the three cranks being arranged at such
angles as to best equalize the strain upon and balance the pistons rods and cranks.
By this arrangement I permit a greater degree of expansion being used in the two
high pressure cylinders which expansion may be governed or accomplished by any
convenient means of expansion gear so that there will be a large reduction in the
quantity of steam used for the power developed and a much more steady motion. of
the engine than in the ordinary compound engine.
The additional high pressure cylinder may be provided with two exhaust branches
or ports so arranged that connection therewith may be formed with either the low
pressure valve casing, or at such time as the engines are to be worked with extra
high pressure steam, with the valve casing of the other high pressure cylinder according
to the way the engines are to be used that is to say either both high pressure cylinders
will exhaust into the low pressure slide valve casing or the steam from the additional
cylinder may be caused to enter the intermediate cylinder valve casing when so
required and in this latter case the exhaust from the intermediate cylinder will of
course be led to the valve casing of the low pressure cylinder.
When the pressure in the boilers of triple expansion engines require reducing in
consequence of deterioration through age, or other cause the engines may be
converted into compound engines having two high pressure cylinders and one low
pressure cylinder by inserting a liner of a diameter suited to the pressure to be used
in the intermediate cylinder and altering the steam passages so as to conduct the
steam into the two smaller cylinders direct from the boiler, and from both of the said
cylinders into the low pressure cylinder.
And in order that my said Invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the figures
on the annexed drawings the same letters of reference indicating corresponding parts
in all the Drawings.

page_text: Figures 1 and 3 are longitudinal sections through the cylinders of two engines
having different arrangements of the slide valve casings.
Figures 2 and 4 are plans of the cylinders of the compound engines shewn in
Figures 1 and 3 respectively. Both engines are constructed and arranged according
to my Invention, A being the low pressure cylinder B the ordinary high pressure
cylinder and C the additional high pressure cylinder. The cylinders B and are
shown in Figures 1 and 2 as having each independent valve chests b, a, respectively
but if desired the valves d e for both cylinders may be contained in one and the same
chest.
In Figures 3 and 4 the valve chests are disposed differently, those for the
cylinders A and B being in close proximity and the valve chest a for the cylinder (
being arranged to the left hand of that cylinder as shown. The valve chests a b
(Figures 1 and 2) and the valve chests (Figures 3 and 4)-are separated by a
partition e provided with faces ff against which the backs of the valves c d (Figures 1, 2)
or d (Figures 3, 4) work. The valves may be double or single ported or piston valves
as preferred.
.
Live steam from the boilers is conducted into the valve chests a 6 by a pipe G
having branches g g² leading respectively into the said valve chests a b, the branch g²
may or may not be provided with a cock or valve g¹ (Figure 2) for cutting off the
supply of steam to the chest b when required. The additional cylinder (may at first
be fitted with or may remain without a liner and may be of the capacity usual for the
high pressure cylinder of triple expansion engines as shown at 2 but I prefer to make
it of greater diameter and fit therein a larger removable liner as at h of such diameter
as to leave a space between it and the cylinder, which cylinder then constitutes a
jacket to prevent or reduce loss of heat by radiation.
The cylinder is shown in the drawing with two liners h h of different diameters
that shewn at being employed when both cylinders B and C receive high pressure
steam from the boilers direct and that shewn at h2 (which is of less diameter) being.
substituted for / when the engine is to be worked as a triple expansion engine-the
piston of course being changed to correspond to the diameter of the liner employed.
When the cylinders B and C both receive high pressure steam direct, they both
exhaust into the space or exhaust chamber i which surrounds the cylinder B, (or may
exhaust into the low pressure cylinder slide valve casing by a pipe direct) the steam
from the cylinder C being conducted into the said space by the exhaust pipes D D.
The space is in communication with or forms part of the valve chest k of the low
pressure cylinder A. and the passage of steam from this space to the said cylinder is
governed by the slide valve l. After the steam has done its work in the cylinder A.
it may exhaust into a condenser or into the atmosphere if desired.
The arrangement of pipes or passages for the steam to and from the cylinders may
be varied as required to suit different arrangements of the cylinders and may be
provided with cocks or valves for directing the steam in the required direction.
When the engine is to be worked as a triple expansion engine the liner is removed
from the cylinder C and the liner / fitted in place thereof which is of smaller diameter
proportional to the new Boiler pressure intended to be used and the valve g¹ in the
branch g² leading to the valve chest 6 of the cylinder B is closed or (where no valve is
employed as in Figures 3 and 4 the pipe connection with the valve chest b is removed)
the connections of the exhaust pipes D'with the space i are broken at D¹ and connected
as shewn by dot and pick lines to a passage at D' with the slide valve chest b.
Steam from the boiler is conducted by the branch pipe g into the valve chest a and
after doing work in the cylinder C exhausts by the pipes D and passage D² into the
valve chest of the cylinder B in which it then works expansively and after doing
its work therein passes into the valve chest k and thence by the valve into the low
pressure cylinder A. wherein it acts by further expansion on the piston therein and
finally exhausts into a condenser or into the atmosphere.
Instead of altering the connections of the exhaust pipes as hereinbefore described
the said pipes may be provided with valves and branch pipes for directing the steam
in the course required but as the necessity for altering the course of the steam is not

page_text: frequent the arrangement herein before described and illustrated is preferred on account
of economy in cost.
The intermediate cylinder of triple expansion engines may be readily converted into
a bigh pressure cylinder by inserting therein a liner and piston of the required
diameter for pressure to be used and suitably altering the steam passages so as to admit
live steam from the boiler into the said cylinder as well as into the ordinary high
pressure cylinder and causing both cylinders to exhaust into the low pressure
cylinder valve casing or casings according to my Invention.
By means of my Invention the necessity for providing new boilers when those in
use are only partially worn and too weak to be employed with triple expansion
engines is obviated, whilst the expense of adding the third cylinder and converting
the engine is comparatively light it bein, simply necessary to provide this third
cylinder with piston, connecting rod valve gear and extra crank shaft and pin and to
alter the connections of the steam passages substantially as herein before described.
Having now described and particularly ascertained the nature of my Invention
I wish it to be understood that as this Invention is intended for the improvement
more particularly of the working of existing engines I do not restrict myself to the
arrangement of the cylinders as shewn in either of the drawings nor to the details
of construction described and illustrated, as variations may be made therein without
departing from the nature of my Invention but what I claim is :-
1. A compound engine having three cylinders two of the said cylinders being
supplied with high pressure steam direct from the boilers and exhausting into the
third or low pressure cylinder and the pistons of the three cylinders being connected
to separate cranks arranged at different angles on the same crank shaft substantially as
hereinbefore described.
2. A compound engine with three cylinders one of the said cylinders being provided
with a removeable liner, and the steam passages being so arranged that the engine
may be worked either with two high pressure cylinders or as a triple expansion
engine substantially as hereinbefore described.
3. The general construction arrangement and combination of parts constituting
a three cylinder compound engine substantially as and for the purpose hereinbefore
described with reference to Figures 1 and 2 of the accompanying drawings.
4. The general construction arrangement and combination of parts constituting
a three cylinder compound engine substantially as and for the purpose hereinbefore
described with reference to Figures 3 and 4 of the accompanying drawings.
Dated this 20th day of August 1889.
ANDREW LECKIE.