AN IMPROVEMENT IN AIR ENGINES
Year: 1825

page_text: GRISENTHWAITE'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
GRISENTHWAITE, of King's Place, Nottingham, Gentleman, send greeting.
WHEREAS His present most Excellent Majesty George the Fourth, by
His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Fifteenth day of March 1825, in the sixth year of His
reign, did, for Himself, His heirs and successors, give and grant unto me, the
said William Grisenthwaite, His especial licence, that I, the said William
Grisenthwaite, my executors, admors, and assigns, or such others as I, the said
William Grisenthwaite, my exors, admors, and assigns, should at any time
agree with, and no others, from time to time and at all times during the term
of years therein expressed, should and lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick-upon-Tweed, my
Invention of "AN IMPROVEMENT IN AIR ENGINES;" in which said Letters Patent
there is contained a proviso, obliging me, the said William Grisenthwaite, by
an instrument in writing under my hand and seal, particularly to describe and
ascertain the nature of my said Invention, and in what manner the same is to
be performed, and to cause the same to be inrolled in His Majesty's High Court
of Chancery within six calendar months next and immediately after the date
of the said in part recited Letters Patent, as in and by the same, reference
being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
William Grisenthwaite, do hereby declare that the nature of my said Inven-
tion, and the manner in which the same is to be performed, is described and
ascertained as follows. (that is to say):-

page_text: I provide a stove or furnace (one resembling in shape those employed to
heat rooms will answer very well, only that it should be coated with fire clay or
some other bad conductor of heat), and above the fuel (which will be described
hereafter) I place a plate of metal perforated with holes, upon which plate I
place a quantity of any incombustible substance, in order to accumulate the
radiant heat of the fire, and to prevent the passage of any dust into a pipe which
I employ to connect the said furnace or stove with a cylinder. The cylinder
to which I have just alluded resembles the cylinder of a common condensing
steam engine, and the pipe above mentioned corresponds to the steam pipo of
such common condensing steam engines, having in it a similar cock, and which
cock is moved (opened and shut) in the same manner. To the top and bottom
of the said cylinder is attached a pipe or pipes for injecting water into the said
cylinder, and in this pipe or these pipes is or are a cock or cocks, which is or
are opened and shut by the engine itself when in action, to answer a purpose
very similar to the injection of cold water into tho cylinder of the original
steam engines. To the bottom of the said cylinder is attached a pipe with a
valve in it opening outwards. This pipe serves to carry off the condensed air
and water (hereafter to be described), which would otherwise remain in the
said cylinder at the end of every descending stroko. For freeing the upper
part of the said cylinder from the above-mentioned condensed air and water
I make the upper part of the piston (which works in the said cylinder) in
the form of an inverted truncated cone, with a well in it to receive the above-
mentioned condensed water, and the piston rod is made hollow for about a foot
from the end next the piston, and is furnished with a valve opening upwards,
and there is also a hole made through the said piston rod to allow the above-
mentioned condensed air and water to escape into the open air or into a vessel
placed to receive them.
Having described the particulars and the arrangement of the apparatus, I
shall now proceed to describe the manner of employing them.
I put into the stove or furnace above mentioned a quantity of any solid
combustible substance or substances, as carbon, &c. in a state of combustion,
I then close the door of the said stove or furnace, and turn the fly wheel (it
being all along understood that this engine resembles a common condensing
steam engine) which moves the piston of the said cylinder, opens the cock
which connects the said cylinder with the said stove or furnace, and occasions
a quantity of air (heated by its passage through the above-mentioned com-
bustible substance or substances, as well as by the heat actually generated by
the union of its oxygon gas with the matter of the combustible substance or
substances,) to enter and fill the said cylinder. When the said cylinder is so

page_text: filled with heated air, the above-mentioned injection cock is opened, and a jet
of water enters the said cylinder, cools the heated air, and produces a partial
vacuum. The immediate consequence of this is a rush of air through the
above-mentioned stove or furnace to the side of the piston opposite to the said
partial vacuum, which presses down the piston with considerable force, and
communicates, through the medium of the piston rod beam, &c., a motion to
the fly wheel, and this motion continues after the balance of elasticity is
restored on both sides of the piston sufficiently so to drive out the condensed
air and water (which were to be described) through the pipe furnished with a
valve opening outwards or through the piston rod, as have been before described.
At the end of this step of the operation the cock at the other end of the said
cylinder (the end now filled with heated air) is opened, and a jet of cold water
enters the said cylinder, and produces a condensation in like manner as before
on the other side of the piston, and with similar consequences, and thus power
is continued to be produced which may be communicated to any kind of
machinery, and may be applied to any of the purposes that the power of steam
engines is applied.
I claim no part of the apparatus above described, except the additions made
to the stove or furnace for accumulating the heat and interrupting the passage
of dust, and the contrivance for freeing the cylinder of air and water by a
hollow piston rod and valve. I claim to be the first and true Inventor of the
above method of applying heated air and effecting its subsequent condensation
for the production of motive power; in other words, I claim to be the first
Inventor of the above method of producing a partial vacuum by the conden-
sation of air heated and generated by passing it through a mass of solid com-
bustible substances in a state of ignition. It may be further remarked, that
the working cylinder should be kept as near to the temperature of the internal
air as possible. It is also convenient to attach a pipe to the top of the furnace
or stove with a cock in it, by which at pleasure a communication may be made
between the upper part of the said stove or furnace and the atmosphere, as by
this arrangement the engine may be reduced in its power by simply opening
the cock, and a correspondent reduction in the quantity of fuel consumed will
also ensuc.
In witness whereof, I, the said William Grisenthwaite, have hereunto
set my hand and seal, this Ninth day of September, in the year of our
Lord One thousand eight hundred and twenty-five.
WILLIAM (Ls.) GRISENTHWAITE.

page_text: AND BE IT REMEMBERED, that on the Ninth day of September, in the
year of our Lord 1825, the aforesaid William Grisenthwaite 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 Tenth day of September, in the year of our Lord One
thousand eight hundred and twenty-five.