IMPROVE- MENTS IN STEAM PUMPS AND ENGINES
Year: 1871

page_text: LETTERS PATENT to John Clarkson, of Glasgow, in County of
Lanark, North Britain, Engineer, for the Invention of "IMPROVE-
MENTS IN STEAM PUMPS AND ENGINES."
Sealed the 10th May 1872, and dated the 15th November 1871.
PROVISIONAL SPECIFICATION left by the said John Olarkson at the
Office of the Commissioners of Patents, with his Petition, on the
15th November 1871.
I, JOHN CLARKSON, of Glasgow, in the County of Lanark, North
Britain, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN STEAM PUMPS AND ENGINES," to be as follows, that is
to say:-
This Invention relates in part to improved and simplified arrange-
ments for distributing steam alternately to opposite ends of a cylinder,
and specially designed for a steam pump, but also applicable to other
steam engines, and in part to an improved mode of applying throttle
valves to steam engines when connected to governors.

page_text: throttled; but if the exhaust is throttled as proposed, the consequent
accumulation of the back pressure steam will act as an effective though
elastic brake.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Clarkson in the Great Seal Patent Office on
the 14th May 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
CLARKSON, of Glasgow, in the County of Lanark, North Britain,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifteenth day of November, in the
year of our Lord One thousand eight hundred and seventy-two,
in the thirty-fifth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said John Clarkson, Her
special licence that I, the said John Clarkson, my executors, adminis-
trators, and assigns, or such others as I, the said John Clarkson, my
executors, administrators, 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 STEAM PUMPS AND ENGINES," upon the condition (amongst others) that
I, the said John Clarkson, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, 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

page_text: exhaust in consequence of its passage (10) being open to the space
between the piston ends 11, 12, which space communicates by a port 13
with the exhaust 8. The valve piece 5, 6, is thus moved backwards and
forwards without any external gearing; and I may mention that it may
be prevented from knocking undesirably against the end covers of the
valve chamber 4 by suitably proportioning the additional passages 9, 10;
or if preferred, screw valves or plugs may be fitted to these to admit
of the effective passage through them being regulated at any time.
In my Provisional Specification relative hereto there was described a
modification in which a valve was to work across one or each of the ends
of the cylinder; I do not however now consider such modification of
such utility as to justify me in making any claim respecting it, and it is
therefore unnecessary to further describe it herein.
My said Invention further consists in applying a throttle valve when
in connection with a governor to the exhaust passage of a steam engine
instead of or in addition to the usual throttle valve in the steam inlet
passage. With the old arrangement when the load of the engine is
suddenly reduced the momentum of the parts and the steam in the
engine often cause the engine to race, although the steam inlet is at once
throttled; but if the exhaust is throttled as proposed, the consequent
accumulation of back pressure steam will act as an effective though
elastic brake. The throttle valve thus applied may be of any of the
kinds usually applied to inlet steam pipes, and it may be applied to the
exhaust pipe or passage in the same way as to the inlet steam pipe.
Having thus particularly described my said Invention, and the manner
in which the same is to be performed, I have to state that I do not
restrict myself to the precise details herein described or delineated; but
that what I believe to be novel and original, and claim as the Invention
secured to me by the herein-before in part recited Letters Patent
is,―

page_text: 2. The applying of a throttle valve in connection with a governor to
the exhaust passage of a steam engine instead of or in addition to the
usual throttle valve in the steam inlet passage, as herein-before
described.
In witness whereof, I, the said John Clarkson, have hereunto set 5
my hand and seal, this Thirteenth day of May, in the year of
our Lord One thousand eight hundred and seventy-two.
described.
In witness whereof, I, the said John Clarkson, have hereunto set 5
my hand and seal, this Thirteenth day of May, in the year of
our Lord One thousand eight hundred and seventy-two.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JOHN CLARKSON. (L.S.)