Improved Method of and Means for Diminishing Condensation in Steam Engine Cylinders.
Year: 1889

page_text: Date of Application, 31st July, 1889
Complete Specification Left, 21st Apr., 1890-Accepted, 24th May, 1890
PROVISIONAL SPECIFICATION.
Improved Method of and Means for Diminishing Condensation in
Steam Engine Cylinders.
I LOUGHNAN ST. LAWRENCE PENDRED, Engineer, of Grinstead House, Colchester
do hereby declare the nature of this invention to be as follows:-
It is well known that when steam does work in a cylinder, the metal is cooled
down during the period of exhaust, and a portion of the steam admitted during the
next stroke is condensed as it comes into contact with the cold metal.
Much of the cooling is due to evaporation of condensed steam during the exhaust
period, brought about by the fall in pressure.
In order to reduce this condensation I proceed as follows. I make an engine
having one or more, by preference two, single acting cylinders, and I supply steam
to these cylinders by separate pipes or their equivalent leading from the boiler, one
pipe conveys what I term heating steam to one end of each cylinder, and while the
engine is running this pipe is always open and there is a constant pressure exerted
on the piston. The other conveys what I term working steam to the other end of
each cylinder and it is admitted and exhausted by suitable valves in any way found
convenient. When two cylinders are employed the cranks are placed 180° apart.
As the piston moves in the cylinder during the exhaust stroke, the heating steam
follows it up and raises the temperature of the metal. A portion is condensed and
the resulting water may be withdrawn by a steam trap or drained back into the
boiler.
The working steam will then find during the next stroke the metal hotter than
itself instead of cooler, and its efficiency will be promoted. The water deposited
from the heating steam will not be reevaporated in the cylinder, and thus a saving
in fuel will be effected according to well known thermo dynamic laws.
I apply the same invention to compound engines in various ways.
Thus I fix two pistons of different diameters on the same rod, and I work them in
two tandem cylinders freely open to each other and introduce heating steam between
the two pistons, while the working steam is first admitted for one stroke to the. small
cylinder, from which it exhausts to the large in a way too well understood to need
description. I make a double acting engine by using a cylinder larger than the
stroke, and in it I put two pistons of the same diameter secured to the same rod at a
suitable distance apart, and to the space between the two I admit heating steam through
a suitable port, and the working steam I admit and exhaust in the ordinary way
between the cylinder covers and the pistons.
T1 90
1000
LOUGHNAN ST. LAWRENCE PENDRED.
COMPLETE SPECIFICATION.
Improved Method of and Means for Diminishing Condensation in
Steam Engine Cylinders.
I LOUGHNAN ST. LAWRENCE PENDRED, of Greenstead House Colchester, Mechanical
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 :-
It is well known that when steam does work in a cylinder the metal is cooled
down during the period of exhaust, and a portion of the steam admitted during
the next stroke is condensed as it comes into contact with the cold metal, much of

page_text: the cooling is due to evaporation of condensed steam during the exhaust period
brought about by the fall in pressure. In order to reduce this condensation I
proceed as follows. I make an engine having one or more, by preference two, single
acting cylinders, and I supply steam to these cylinders by separate pipes leading
from the boiler, one pipe conveys what I term heating steam to one end of each
cylinder, and while the engine is running this pipe is always open and there is a
constant pressure exerted on the piston. The other conveys what I term working
steam to the other end of each cylinder, and it is admitted and exhausted by suit-
able valves in any way found convenient. When two cylinders are used the cranks
are placed 180° apart. As the piston moves in the cylinder during the exhaust
stroke the heating steam follows it up, and raises the temperature of the metal.
portion is condensed and the resulting water may be withdrawn by a steam trap or
drained back into the boiler. The working steam will then find during the next
stroke, the metal hotter than itself instead of cooler, and its efficiency will be
promoted. The water deposited from the heating steam will not be reevaporated in
the cylinder, and thus a saving in fuel will be effected according to well known
thermo-dynamic laws.
A
I apply the same invention to compound engines in various ways. Thus I fix two
pistons of different diameters on the same rod, and I work these in tandem cylinders
freely open to each other, and introduce heating steam between the two pistons
while the working steam is first admitted for one stroke to the small cylinder from
which it exhausts to the large, in a way too well understood to need description: I
make a double acting engine by using a cylinder longer than the stroke and in it I
place two pistons, of the same diameter secured on the same rod, at a suitable
distance apart, and to the space between the two I admit heating steam through a
suitable port, and the working steam I admit and exhaust in the ordinary way between
the cylinder covers and the pistons.
In order that the nature of my invention may be more clearly understood I annex
a sheet of drawings.
Fig. 1 shows that portion of a single cylinder single acting engine to which my
invention applies. A is the working cylinder enclosed in a jacket B to which heating
steam is constantly supplied by the pipe D. The working steam is supplied by the
pipe E. The piston valve worked by the eccentric H is shown at F. The exhaust
port is shown at G. The piston rises as shown clear of the top edge of the cylinder A
in order that any water deposited on it may be pushed over into the jacket from
which it will escape by the pipe C leading to a steam trap. The action of the valve.
is too obvious to require description. The piston is supposed to be just commencing
its descent with full boiler pressure on top of it, and the piston valve is rising and
opening the exhaust a slide or any other suitable valve may be used instead of a piston
valve.
In Fig. 2 I have shown one form of compound engine constructed according to my
invention as herein before described. The tandem cylinders are shown by A. The
low pressure cylinder only is placed in a jacket, but the jacket may be fitted to
either or both. The heating steam is admitted through the port D. The working
steam is supplied through E, the action of the piston valves is sufficiently obvious.
The pistons supposed to be just commencing to descend, impelled by the pressure on
the top of the small piston and by the difference in total pressures due to the difference
in areas of the two pistons, said pressures being caused by the heating steam between
On the return stroke steam will flow from above the small piston to below
the large one. The difference in driving force on the crank during the up and
down strokes is compensated either by a fly wheel or by using two sets of tandem
engines with cranks opposite each other. In some cases however I invert one set
of cylinders so that one connecting rod is always in tension while the other is always
in compression.
the two.
Fig. 3 shows my Invention applied as herein before described to a double acting
cylinder. A is the cylinder more than twice as long as the stroke. The two pistons
are shown at J J. The space between them communicates directly with the boiler Ķ

page_text: by the port D. The cylinder ports are shown at I I. No valves are shown because
they form no part of my Invention.
Having now particulary described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is.
Heating the metal of steam engine cylinders and preventing or diminishing evapora-
tion in them by maintaining pressure in them substantially as herein before described,
to diminish condensation.
Dated this Eighteenth day of Ancil 1800
LOUGHNAN ST. LAWRENCE PENDRED.