CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1833

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
PETRIE, of Rochdale, in the County of Lancaster, Machinist and Engineer,
send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-fifth day of July, in the fourth year of His reign,
did, for Himself, His heirs and successors, give and grant unto me, the said
John Petric, His especial licence, sole privilege and authority, that I, the
said John Petrie, my exors, adññiors, and assigns, or such others as I, the said
John Petrie, my exors, adiñors, or assigns, should at any time agree with,
and no others, from time to time and at all times during the term of years
therein mentioned, should and lawfully might make, use, exercise, and vend,
within England, Wales, and the Town of Berwick-upon-Tweed, my Invention
of "CERTAIN IMPROVEMENTS IN STEAM ENGINES;" in which said Letters Patent
is contained a proviso that I, the said John Petrie, shall cause a particular
description of the nature of my said Invention, and in what manner the
same is to be performed, to be inrolled in His said Majesty's High Court
of Chancery within six calendar months next and immediately after the date
of the said in part recited Letters Patent contained, as in and by the same,
reference being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
John Petrie, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is particularly described and
ascertained in and by the following description thereof, reference being had to
the Drawing hereunto annexed, and to figures and letters marked thereon
(that is to say):
My Invention consists in raising to the boiling point or to the temperature of
212° of Fahrenheit's thermometer all the feed water (during the time the engine
is at work), previous to the said water, entering the boiler, whereby much fuel
is saved, the said temperature being communicated to the water by the steam
which leaves the cylinder after operating on the piston; and my method of
producing the aforesaid effect is as follows:-In a condensing engine, previous
to the steam from the working cylinder entering the condenser, I cause it to
enter a vessel (which vessel I denominate a "caloric extractor"), into which
vessel, by means of a force pump or by means of the vacuum which is inside
the said vessel, I inject such a quantity of water as is sufficient for feeding the
boiler, which water, by mixing with the steam as the said steam passes from
the cylinder through the extractor to the condenser, acquires in combination
with the product of condensation, a temperature equal to that of boiling water,
or 212° of Fahrenheit's thermometer. From the bottom of the extractor
proceeds a pipe which is connected with the feeding pump of the boiler, and if
more water is injected than is requisite to supply the pump of the boiler, the
surplus, after filling the lower part of the extractor, passes out of it into the,
the condenser. The difference between the ordinary condenser and my
caloric extractor is this: while the condenser is made and kept as cool as
possible by the requisite quantity of water for that purpose (that a good
vacuum may be effected), the caloric extractor is used on the contrary to
raise the temperature of the feeding water to the boiling point, and no more
water should be admitted than the heat of the steam will raise to that"
temperature. In a high-pressure engine I place the caloric extractor as
near the working cylinder as may be convenient, and connected thereto by a
pipe for conducting the exit or eduction steam into the said extractor, through
which extractor the steam is made to pass before it is discharged into the
atmosphere or into the chimney, which latter I prefer whenever circumstances
render it easily practicable. Below the commencement of the discharging
pipe, and in the top of the extractor, I fix a kind of cullender, perforated plate,
or perforated pipe, or other contrivance, on which plate, or through which pipe
or other contrivance, I direct a sufficient quantity of water for the boiler,
whence falling through the steam in a continual shower or constant stream it

page_text: becomes heated to 212°, and is deposited at the bottom of the extractor,
whence it is drawn by a pipe which is in connexion with the feed pump; the
excess of water runs off by a pipe placed a little higher than the suction pipe
of the pump. To regulate the quantity of water directed into the extractor, a
cock is fixed in the supply pipe, and on outlet cock is placed between the
pump and the boiler to regulate the quantity sent into the boiler. As in the
case of a condensing engine, no more water should be admitted into the
"caloric extractor," when most efficiently used, than can be raised in tem-
perature to 212°. In order to render the foregoing description more easily
intelligible, a diagram for each kind of engine, explanatory of the several
is hereunto annavad
JOHN (L.s.) PETRIE

page_text: AND BE IT REMEMBERED, that on the Twenty-first day of January,
in the year of our Lord 1834, the aforesaid John Petrie came before our
said Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that purpose.
Inrolled the Twenty-fourth day of January, in the year of our Lord One
thousand eight hundred and thirty-four.