IMPROVEMENTS IN THE METHOD OF AND APPARATUS FOR PRODUCING A TEMPORARY VACUUM OR PARTIAL VACUUM IN CONDENSERS, PASSAGES, AND OTHER LIKE PARTS OF STEAM ENGINES
Year: 1877

page_text: LETTERS PATENT to George Rodger, of Barrow-in-Furness, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN THE METHOD OF
AND APPARATUS FOR PRODUCING A TEMPORARY VACUUM OR PARTIAL VACUUM
IN CONDENSERS, PASSAGES, AND OTHER LIKE PARTS OF STEAM ENGINES."
Sealed the 5th February 1878, and dated the 8th October 1877.
PROVISIONAL SPECIFICATION left by the said George Rodger at the Office
of the Commissioners of Patents on the 8th October 1877.
GEORGE RODGER, of Barrow-in-Furness, in the County of Lancaster, Engineer.
"IMPROVEMENTS IN THE METHOD OF AND APPARATUS FOR PRODUCING A TEMPORARY
VACUUM OR PARTIAL VACUUM IN CONDENSERS, PASSAGES, AND OTHER LIKE PARTS
OF STEAM ENGINES."
My Invention has for its object the production of a temporary vacuum or partial
vacuum in the condenser or condensers, passages, and other like parts of marine or
other steam engines for the purpose of overcoming the difficulty often experienced
in starting steam engines (especially those of the two-cylinder compound type), by
providing a partial vacuum ready formed, so that the low-pressure piston may at
once take a part in the work of turning the crank shaft.
The usual process of arriving at this result has been by using a blow-through and
a snifting valve, and introducing steam into the condenser and passages, and driving
out the air through the snifting valve, and afterwards obtaining a vacuum by
condensing the steam in the condenser and passages by a spray of water, the blow-
through and snifting valves being closed as soon as the engine is set to work.
The chief objections to this process are the danger of heating the condenser, the
difficulty of application to surface condensers.
According to my Invention I produce the temporary or partial vacuum by the
means of a jet, or a number of jets, of any suitable fluid (by preference steam),

page_text: which are applied by means of an apparatus, being a vessel with two branches, one
of which, being the exhaust air passage, is bolted to or in connection with the
condenser; and the other, being the discharge passage, lies at right angles thereto.
The vessel is provided with a steam nozzle, being an internal pipe, which lies across
the exhaust air passage, and enters the discharge passage. The steam nozzle is
capable of adjustment, and is provided with a suitable valve or steam cock. The
apparatus is also provided with a valve to shut it off from the condenser or other
part to which it is applied.
In operation, the apparatus being open to the condenser and a steam jet issuing
from the nozzle, the air is drawn from the condenser by the action of the steam,
and ejected with the steam through the discharge passage. By this means I am
enabled to obtain a vacuum equal to, say, 20 inches of mercury, and to dispense
with the process of blowing through, and thus avoid heating the condenser.
My Invention is also applicable to jet or surface condensers.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Rodger in the Great Seal Patent Office on the 2nd April
1878.
GEORGE RODGER, of Barrow-in-Furness, in the County of Lancaster, Engineer.
"IMPROVEMENTS IN THE METHOD OF AND APPARATUS FOR PRODUCING A TEMPORARY
VACUUM OR PARTIAL VACUUM IN CONDENSERS, PASSAGES, AND OTHER LIKE PARTS
OF STEAM ENGINES."
My Invention bas for its object the production of a temporary vacuum or partial
vacuum in the condenser or condensers, passages, and other like parts of marine or
other steam engines, for the purpose of overcoming the difficulty often experienced
in starting steam engines (especially those of the two-cylinder compound type), by
providing a partial vacuum ready formed, so that the low-pressure piston may at
once take a part in the work of turning the crank shaft.
The usual process of arriving at this result has been by using a blow-through
and a snifting valve, and introducing steam into the condenser and passages, and
driving out the air through the snifting valve, and afterwards obtaining the vacuum
by condensing the steam in the condenser and passages by a spray of water, the
blow-through and snifting valves being closed as soon as the engine is set to work.
The chief objections to this process are the danger of heating the condenser, and the
difficulty of application to the surface condensers.
According to my Invention I produce the temporary or partial vacuum by the
means of a jet, or a number of jets (of any suitable fluid, by preference steam),
which are applied by means of an apparatus, such as a vessel with two branches,
one of which, being the exhaust or suction passage, is bolted to or in connection
with the condenser, passage, or other like part to be exhausted; and the other,
being the discharge passage, lies at right angles thereto. The vessel is provided
with a steam nozzle, being an internal pipe, which lies across the exhaust air
passage, and enters the discharge passage. The steam nozzle is capable of adjust-

page_text: ment, and is provided with a suitable valve or steam cock. The apparatus is also
provided with a valve to shut it off from the condenser or other part to which it is
applied.
In operation, the apparatus being open to the condenser and a steam jet issuing
from the nozzle, the air is drawn from the condenser by the action of the steam,
and ejected with the steam through the discharge passage. By this means I am
enabled to obtain a vacuum equal to, say, 20 inches of mercury, and to dispense
with the process of blowing through, and thus avoid heating the condenser.
My Invention is applicable to jet or surface condensers.
The nature, object, and purposes of this my Invention having been thus set forth,
I will now proceed to describe in detail how the same may be practically carried
out, and for that purpose I have hereunto annexed a Sheet of Drawings, which
sufficiently illustrates iny Invention to enable any engineer to carry the same into
practical effect.
Like letters marked on the Drawings denote similar or corresponding parts
throughout the various views.
Figure 1 is a sectional elevation of an ejector or exhauster constructed according
to my Invention, and such as may be used to carry out the object of my
Invention.
Figure 2 is an end view of Figure 1.
Figure 3 is a plan of Figure 1.
Figure 4 is an elevation of a pair of marine engines of the two-cylinder compound
type, showing my Invention applied thereto.
Figure 5 is a plan of Figure 4.
Upon reference to the exhauster, shown at Figures 1, 2, and 3, it will be seen
that the apparatus consists of a vessel A, which is provided with a steam nozzle B
(which may be adjustable or fixed). The vessel A is bolted to a non-return valve C,
which is in connection with the condenser or condensers, passages, or other like
parts of a steam engine, through its branch D; E is a steam cock, which is
attached to and supplies the vessel A with steam through the nozzle B. A suitable
pipe may be led from the vessel A, in connection with the branch F, conveying the
steam and exhausted air to any required position.
The application of my Invention is illustrated by Figures 4 and 5.
Upon reference, it will be seen that H is the low-pressure and J the high-pressure
cylinders of a marine engine of the compound type; K is the exhaust pipe, or
passage from the cylinder H to the condenser. An exhauster, such as illustrated
at Figures 1, 2, and 3, is applied at M, and is controlled by the hand gear N. The
branch F of the exhauster communicates with the ship's side through the pipe P
and the cock S.
In operation, steam being admitted to the exhauster through the cock E and
nozzle B, air is drawn from the passage K and the condenser by the action of the
steam jet passing through the nozzle B, the air and steam being discharged through
the pipe P and cock S. By this means I obtain a partial vacuum in the passage K
and condenser, equal to, say, 20 inches mercury; and I can thus dispense with the
process of blowing through, and avoid heating the condenser; and I am enabled to
bring the low-pressure cylinder into operation, so that its piston may at once take
share in the work of turning the crank shaft.
Having now described and ascertained the nature of my Invention, and shown how
the same may be carried out into practical effect, I would have it clearly understood
that I do not confine myself to the precise dimensions or design of the exhauster or
ejector, shown in the Drawings, for carrying out my Invention, as the same is
capable of an indefinite variety of modification; I would also have it understood
that I do not confine myself to the particular position of application of my Invention,
as shown in the Drawings, as the same is capable of various modification; but what
I claim as my Invention, and secured to me by the herein-before in part recited
Letters Patent is, the method of obtaining a temporary or partial vacuum in con-
densers, passages, and other like parts of steam engines by the use and application

page_text: of an ejector or exhauster, such as heroin-before described, and shown at Figures
1, 2, and 3 of the accompanying Drawings, or any modification thereof.
In witness whereof, I, the said George Rodger, have hereunto set my hand
and seal, this Eighteenth day of March, in the year of our Lord One
thousand eight hundred and seventy-eight.
AXA
GEORGE (L.S.) RODGER.