IMPROVEMENTS IN STEAM ENGINES
Year: 1874

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN STEAM ENGINES."-A communication from abroad
by Augustin Harmignies, Engineer, of Paris, in the Republic of
France.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 21st February 1874.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN STEAM ENGINES," a communication
to me from abroad by Augustin Harmignies, Engineer, of Paris, in the
Republic of France, to be as follows:-

page_text: through the blast pipe or pipes when the engine is reversed, and consists
in closing such blast pipe or pipes by means of a slide or damper pro-
vided with a spring valve, which slide or damper is brought into action
when desired by the motion of a lever or otherwise, so as to admit of
the escape of any excess of pressure which may occur underneath it,
whilst at the same time excluding air.
A cock for the supply of cold water to the pipe or pipes is provided
in combination with this apparatus, such cock being operated auto-
matically through a rod or otherwise by the lever, or other means
employed for adjusting the position of the slide or damper, so that
when the slide or damper is closed the cock will be open, and vice
versa, whereby the pistons and packings are maintained in a sufficiently
cool condition. The cold water is drawn in by means of the vacuum
produced by the piston..
By means of this apparatus the increased tension of the steam
occasioned by air being forced into the boiler is obviated, and when
applied to locomotive engines greater facility is afforded for retarding
or arresting the motion of trains without the aid of the brakes ordinarily
employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 2
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 30th July 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
2
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of February, in the
year of our Lord One thousand eight hundred and seventy-four, in
the 37th year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Henry Johnson, Her 3
special license that I, the said John Henry Johnson, my executors,
administrators, and assigns, or such others as I, the said John Henry

page_text: And in order that the said Invention may be fully understood, I
shall now proceed more particularly to describe the same, and for
that purpose shall refer to the two Figures on the annexed Sheet of
Drawings, the same letters of reference indicating corresponding parts
in both Figures.

page_text: Figure 1 of the Drawings represents a transverse section taken through
the smoke box of a locomotive engine, and shewing the application
of the apparatus constructed according to this Invention; and Figure 2
is a corresponding plan of the same.
The slide or damper A which carries the spring valve B is moved
at pleasure by the aid of a lever L, or any other convenient arrange.
ment; in the Drawing it is shewn closed, that is to say, in the
position in which it would be placed for the reversing of the engine.
The apparatus is provided with a cock C which is employed for
the introduction of cold water into the exhaust pipe or pipes in order
to prevent the heating of the pistons, packings, and neighbouring
parts. The cock C is operated automatically by means of the lever L
to which it is connected by the rod 1, such cock being open when
the slide or damper A is closed (in the position shewn in the Drawing),
and closed when the slide or damper is open, allowing free passage
for the exhaust, which is the position they occupy in the normal
working of the engine. The supply of cold water is always sufficient,
the same being drawn in by means of the vacuum produced by the
piston.
This system possesses numerous undeniable advantages, and is of
special importance in its application to locomotive engines, which
with this apparatus will be enabled to retard and promptly arrest the
motion of the trains on the steepest gradients without the aid of the
ordinary brakes, which have the inconvenience of deteriorating the tires
of the wheels, and increasing the wear of the rails.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider to
be novel and original and therefore claim as the Invention secured to mo
by the herein-before in part recited Letters Patent is, the application
and use to and with the blast or exhaust pipe or pipes of a locomotive
or other steam engine of a slide or damper having a valve, such slide
or damper being brought into action as required so as to close the
pipe or pipes, and prevent the ingress of air therethrough, whilst
admitting of the escape of any undue pressure which may occur
underneath the slide or damper, in combination with means for main-

page_text: taining cool the pistons and neighbouring parts of the engine, sub-
stantially in the manner herein-before described and illustrated by the
accompanying Drawings.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, the Thirtieth day of
July One thousand eight hundred and seventy-four.
J. HENRY JOHNSON. (L.S.)