IMPROVE- MENTS IN CONDENSING STEAM ENGINES
Year: 1869

page_text: LETTERS PATENT to Thomas Edwards, of Ladywood, Birmingham, in
the County of Warwick, Engineer, for the Invention of "IMPROVE-
MENTS IN CONDENSING STEAM ENGINES."
Sealed the 22nd February 1870, and dated the 29th December 1869..
PROVISIONAL SPECIFICATION left by the said Thomas Edwards at
the Office of the Commissioners of Patents, with his Petition, on
the 29th December 1869.
I, THOMAS EDWARDS, of Ladywood, Birmingham, in the County of
Warwick, Engineer, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN CONDENSING STEAM ENGINES," to be as follows:-
This Invention has for its object improvements in condensing steam'
engines.
At the present time in condensing steam engines the steam from the
steam cylinder is passed into a close vessel called the condenser, which is
kept cool by means of cold water, and in which a partial vacuum is
maintained by an air pump provided for the purpose. According to my

page_text: Invention I employ no separate air pump, but I maintain a sufficient
vacuum in the condensing vessel by a piston working within it; I also
supply steam over and under this piston in quantity sufficient to give
the required motion to this piston and also to aid the engine.
The arrangement I employ is as follows:-The condenser is a cylinder
with a piston working within it suitably coupled with the main shaft of
the engine, and working in unison with the main steam piston. The
piston of the condenser being, say, at the top of the stroke steam is
admitted over it to cause its return; the steam is soon cut off, and when
the piston has arrived nearly at the bottom of the cylinder a shower of
cold water is thrown into the space over the piston to condense the
highly attenuated steam which this space then contains. When the
piston is at the bottom of the condenser cylinder the steam from the
steam cylinder, and which is required to be condensed, is admitted to
the space over the piston, which remains open to it during the next up
stroke of the piston, and so during the up stroke a partial vacuum is
maintained over the piston. When nearly at the top of the stroke the
piston forces out of the condensor cylinder the condensation and
condensed water by the same passage by which the steam has been
entering from the steam cylinder, and this water is led away in any
convenient manner. At the end of the stroke the valve in this passage
closes. Meanwhile beneath the piston as it gets to the bottom of the
stroke steam is admitted beneath it just as previously on its upper side;
its first action is to sweep out any remaining air and water from beneath
the piston, and then the escape passage closing it acts to force up the
piston, and as it ascends the steam from the steam cylinder is condensed
in the space above it, as before stated. The action on the one side of the
piston is in all respects similar to that on the other side, and so at every
stroke of the engine the work goes on. The steam which is used for
giving motion to the piston in the condenser cylinder and for sweeping
out the remaining air and water from the condenser may be boiler steam,
or it may be exhausted steam from the steam cylinder.
The condensing arrangements above described may be used as a power
engine without being combined with a steam cylinder or cylinders as
ahove stated

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Edwards in the Great Seal Patent Office
on the 29th June 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
EDWARDS, of Ladywood, Birmingham, in the County of Warwick,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of December, in the
year of our Lord One thousand eight hundred and sixty-nine, in the thirty.
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas Edwards, Her special licence that
I, the said Thomas Edwards, my executors, administrators, and assigns,
or such others as I, the said Thomas Edwards, my executors, adminis-
trators, 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 make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN CONDENSING
STEAM ENGINES," upon the condition (amongst others) that I, the said
Thomas Edwards, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly 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 months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Edwards, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement thereof, that is to say :-
This Invention has for its object improvements in condensing steam
engines.
At the present time in condensing steam engines the steam from the
steam cylinder is passed into a close vessel called the condenser, which
is kept cool by means of cold water, and in which a partial vacuum is
maintained by an air pump provided for the purpose.. According to my

page_text: Invention I employ no separate air pump but I maintain a sufficient
vacuum in the condensing vessel by a piston working within it. I also
supply steam over and under this piston in quantity sufficient to give the
required motion to this piston and also to aid the engine.
The arrangement I employ is as follows;-The condenser is a cylinder
with a piston working within it suitably coupled with the main shaft of
the engine, and working in unison with the main steam piston. The
piston of the condenser being, say, at the top of the stroke steam is
admitted over it to cause its return; the steam is soon cut off, and
when the piston has arrived nearly at the bottom of the cylinder a
shower of cold water is thrown into the space over the piston to condense
the highly attenuated steam which this space then contains. When the
piston is at the bottom of the condenser cylinder the steam from the
steam cylinder, and which is required to be condensed, is admitted to
the space over the piston, which remains open to it during the next
up stroke of the piston, and so during the up stroke a partial vacuum is
maintained over the piston. When nearly at the top of the stroke the
valye admitting steam from the engine closes, and the piston forces out
of the condenser cylinder the condensation and condensed water, and
this water is led away in any convenient manner. Meanwhile beneath
the piston as it gets to the bottom of the stroke steam is admitted
beneath it, just as previously on its upper side; its first action is to sweep
out any remaining air and water from beneath the piston, and then the
escape passage closing it acts to force up the piston, and as it ascends
the steam from the steam cylinder is condensed in the space above it, as
before stated. The action on the one side of the piston is in all respects
similar to that on the other side, and so at every stroke of the engine the
work goes on. The steam which is used for giving motion to the piston
in the condenser cylinder and for sweeping out the remaining air and
water from the condenser may be boiler steam, or it may be exhausted
steam from the steam cylinder.
The condensing arrangements above described may be used as a power
engine without being combined with a steam cylinder or cylinders as
above stated.
In order that my said Invention may be most fully understood and
readily carried into effect I will proceed to describe the Drawing hereunto
annexed.

page_text: The Drawing represents condensing apparatus adapted to receive and
condense steam after it has worked in a steam engine cylinder.
a, a, is the condenser cylinder; its cubic contents should be about one
thousand cubic inches per horse-power indicated. 6 is a piston within it
coupled by a piston rod and connecting rod with the main shaft c of the
engine; or in place of coupling the condenser piston with the engine
shaft it may be coupled with an axis driven at equal speed from the
main shaft. The main crank and the condenser crank should be parallel
or nearly parallel the one to the other. d, d, are equilibrium or double-
scated valves serving as the exhaust valves of the steam engine; e, e, are
similar valves to admit steam (by preference boiler steam) for a short
time at the beginning of each stroke to blow the water out of the
condenser cylinder, and destroy the vacuum acting against the piston;
ff, are slide valves opening to allow of the expulsion of the water from
the condenser cylinder, and then immediately closing; g, g', are valves
opening to admit cold water into the condenser cylinder to condense the
steam. The valves d, d, e, e, and f,f, are controlled by cams on the
axes h, h, which are so geared as to rotate at the same speed as the main
shaft of the engine. The axis i is also rotated at the same speed, and by
an eccentric opens the injection valves g and g¹. The valve g admits
the water over a perforated plate at the top of the cylinder, and the
valve up a sliding pipe 6' into the piston b, and over the perforated
plate b*, which forms the bottom of the piston. The Drawing represents
the condenser piston at the bottom of its stroke, and the piston in the
steam cylinder will be in a similar position. At this time, as will be
seen, the exhaust valve d from the upper part of the steam cylinder is
wide open to allow the exhaust steam to enter the condenser over its
piston. This valve remains open until the upward stroke is nearly
completed. The lower steam valve e is also shewn in the Drawing to
be open, as is also the corresponding water escape valve f, and the steam
is in the act of blowing the water and air out of the space beneath the
piston. As soon as the stroke commences the valve f closes suddenly,
but the steam valve e remains open a short time longer. During the
carlier part of the up stroke the upper injection valve g remains open,
and a shower of water is discharged by it into the upper part of the
cylinder, condensing the steam which is at the same time entering from

page_text: the steam cylinder, and after the valve closes the shower will continue
for an instant until the cavity over the perforated plate is empty. When
the piston in the condenser cylinder has made the greater part of its
upward stroke the lower injection valve g' opens and prepares a vacuum
under the piston ready to receive the steam from the lower part of the
steam cylinder as soon as the lower exhaust valve d opens, which it
does as the piston in the condenser approaches the top of the stroke.
The upper escape valve fopens just before the piston reaches the top of
the cylinder, and if the quantity of water in the condenser cylinder is
such that a pressure comes upon the valve before it opens it is able to
leave its seat and permit the water to pass. At the return of the
condenser piston the course of the stroke is similar, as already stated.
In place of admitting boiler steam to the condenser cylinder it is in
the case of compound engines advantageous to use the steam issuing
from the high-pressure cylinder.
The arrangement shown in the Drawing may be worked without
connection with an ordinary steam cylinder, the steam admitted by the
valves e, e, being in sufficient quantity to work the machine and yield
the power desired, and in such case the valves d, d, are put out of action
or removed; but it is in combination with an ordinary steam cylinder
that it is preferred to employ the apparatus. In place of admitting a
shower of condensing water into the condenser cylinder this cylinder
may be coupled with a surface condensing chamber, the arrangements
of which are similar to those of a common surface condenser. Passages
with valves in them connect this chamber with the two ends of the
condenser cylinder. The valves in these passages are similar to the
valves d, d, and they each open and close at the same time as the valve d
at the same end of the condenser cylinder. The air and water pass
back from the condensing chamber into the condenser cylinder, and are
ejected in the manner already described.
Having thus described the nature of my said Invention, and the
manner of performing the same, I would have it understood that what
I claim is, the condensing the exhaust steam of a steam engine in a
separate condensing cylinder where the steam is caused to meet with
a shower of water, which water together with the condensed steam and g
air is expelled from the condensing cylinder by a piston working within
the condensing cylinder with steam admitted behind it.

page_text: I also claim as a modification the arrangement herein-before described
wherein a connection with a surface condensing chamber is substituted
for the admission of condensing water to the condenser cylinder.
I also claim the general arrangement of the apparatus substantially
as described.
In witness whereof, I, the said Thomas Edwards, have hereunto
set my hand and seal, this Twenty-eighth day of June, in the
year of our Lord One thousand eight hundred and seventy.
I also claim the general arrangement of the apparatus substantially
as described.
In witness whereof, I, the said Thomas Edwards, have hereunto
set my hand and seal, this Twenty-eighth day of June, in the
year of our Lord One thousand eight hundred and seventy.