IMPROVEMENTS IN THE CONDENSING APPARATUS OF STEAM ENGINES
Year: 1856

page_text: LETTERS PATENT to William Rennie the younger, of Lagan Foundry,
Belfast, in the Kingdom of Ireland, Engineer, for the Invention of
"IMPROVEMENTS IN THE CONDENSING APPARATUS OF STEAM ENGINES."
"IMPROVEMENTS IN THE CONDENSING APPARATUS OF STEAM ENGINES."
Sealed the 27th March 1857, and dated the 10th October 1856.
PROVISIONAL SPECIFICATION left by the said William Rennie at the
Office of the Commissioners of Patents, with his Petition, on the 10th
October 1856.
I, WILLIAM RENNIE the younger, of Lagan Foundry, Belfast, in the
Kingdom of Ireland, Engineer, do hereby declare the nature of the said.
Invention for "IMPROVEMENTS IN THE CONDENSING APPARATUS OF STEAM ENGINES,"
to be as follows:-
This Invention relates to an improved mode of producing a vacuum in the
cylinders of steam engines, whether the steam in the same be high or low
pressure, whereby the use of the ordinary air pump is obviated, and con-
sequently the prime cost of the engine greatly reduced, and its effective power
increased to a considerable extent.
According to this Invention, the condenser is placed at a considerable
elevation, say thirty-four feet above the hot well, and the air being blown out
of the pipes by the steam from the engine, the water from the hot well will be
made to ascend in the discharge pipe by the pressure of the atmosphere to the

page_text: height of about thirty-three feet. The injection cock is now opened, and
the injection water flows into the condenser and passes down the discharge
pipe; the engine being then started, the exhaust steam is at once condensed
and a vacuum formed without the aid of an air pump. The length of the
exhaust and injection pipes will of course depend on the position of the
engine.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Rennie in the Great Seal Patent Office on the
9th April 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
RENNIE the younger, of Lagan Foundry, Belfast, in the Kingdom of Ireland,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters:
Patent, bearing date the Tenth day of October, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Rennie, Her special license that I, the said William Rennie, my
executors, administrators, and assigns, or such others as I, the said William
Rennie, my executors, administrators, or 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 THE CONDENSING
APPARATUS OF STEAM ENGINES," upon the condition (amongst others) that I; the
said William Rennie, by an instrument in writing under my hand and seal,
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 months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Rennie, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say:
My said Invention relates to an improved mode of producing a vacuum in
the cylinders of steam engines, whether the steam in the same be high or low

page_text: pressure, whereby the use of the ordinary air pump is obviated, and conse-
sequently the prime cost of the engine greatly reduced, and its effective power
increased to a considerable extent.
According to this Invention, the condenser is placed at a considerable
elevation, say thirty-four feet above the hot well, and the air being blown out
of the pipes by the steam from the engine,. the water from the hot well will be
made to ascend in the discharge pipe by the pressure of the atmosphere to the
height of about thirty-three feet. The injection cock is now opened, and
the injection water flows into the condenser and passes down the discharge
pipe; the engine being then started, the exhaust steam is at once condensed
and a vacuum, formed without the aid of an air pump. The length of the
exhaust and injection pipes will of course depend on the position of the
engine.
And in order that my said Invention may be clearly understood, I.shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the Figure on the accompanying Sheet of Drawings, which represents
an elevation of my condensing apparatus adapted to a sixteen horse-power
high-pressure engine.
A represents the cylinder of a high-pressure steam engine; B, the exhaust
pipe, which leads direct to the top of the condenser C. This condenser is
placed at a considerable elevation above the hot well D, say thirty-five feet, and
it communicates direct therewith by the water discharge pipe E. F is the
injection or cold water pipe; and G, the cock, for shutting off or regulating
the injection. The length of the exhaust and injection pipes will depend of
course on the portion of the engine with regard to its elevation above the hot
well; thus, if the hot well be sunk considerably below the engine, the con-
denser will be lower down or nearer to the cylinder, and consequently the
exhaust and injection pipes will be proportionately shorter.
the engine, steam is blown through the pipes for the purpose of expelling the
air therefrom, and so producing a vacuum. The water from the hot well will
thus be made to rise in the discharge pipe E, by the atmospheric pressure,
to the height of about thirty-three feet, or to within a short distance from
the condenser, and will remain at that elevation so long as a vacuum is kept
up in the condenser. The injection water and water of condensation flow
down the discharge pipe into the hot well as fast as they enter the condenser,
gravity alone serving to keep the condenser empty without the aid of an air
pump.
Before starting
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried

page_text: into effect, I would observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of my said Invention; but
what I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is,--
First, the general construction and arrangement of condenser, either for
high or low pressure engines, as herein-before described.
Second, the placing of a condenser, whether for a high or low pressure
steam engine, at such an elevation above the hot well, that the discharge pipe
between the condenser and hot well will be kept full or partially full of water
by atmospheric pressure, whilst the water of injection and condensation is
free to discharge itself from the condenser by gravity alone, without the
necessity of an air pump.
In witness whereof, I, the said William Rennie, have hereunto set my
hand and seal, the Twentieth day of March, One thousand eight
hundred and fifty-seven.
WILLIAM RENNIE. (L.S.)