CERTAIN IMPROVEMENTS IN AN APPARATUS CALCULATED TO SAVE FUEL, AND FOR THE MORE ECONOMICAL CONSUMPTION OF SMOKE, IN SHUTTING FIRE DOORS AND AIR FLUES IN STEAM-ENGINE BOILERS, DYING-PANS, AND BREWING-PANS, AND OTHER FIRE DOORS AND AIR FLUES
Year: 1820

page_text: PRICHARD, of Leeds, in the County of York, Engineer, send greeting.
WHEREAS His most Excellent Majesty King George the Fourth did, by
His Letters Patent under the Great Seal of that part of the United Kingdom
of Great Britain and Ireland called England, bearing date at Westminster, the
Twenty-second day of December, in the first year of His reign, give and gran
unto me, the said William Prichard, my exors, adñiors, and assigns, His
especial licence, full power, sole privilege and authority, that I, the said
William Prichard, my exors, adñiors, and assigns, 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 AN APPARATUS CALCULATED TO SAVE FUEL, AND FOR
THE MORE ECONOMICAL CONSUMPTION OF SMOKE, IN SHUTTING FIRE DOORS AND AIR
FLUES IN STEAM-ENGINE BOILERS, DYING-PANS, AND BREWING-PANS, AND OTHER FIRE
DOORS AND AIR FLUES;" in which said Letters Patent there is contained a pro-
viso that if I, the said William Prichard, shall not particularly describe and
ascertain the nature of my said Invention, and in what manner the same is
to be performed, by an instrument in writing under my hand and seal, and
cause the same to be inrolled in His Majesty's High Court of Chancery within
two calendar monthis next and immediately after the date of the said Letters
Patent, that then the said Letters Patent, and all liberties and advantages
whatsoever thereby granted, shall utterly cease, determine, and become void,
as in and by the same, relation being thereunto bad, will more fully and at
large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
William Prichard, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, are particularly de-
scribed and ascertained in and by the Drawings hereunto annexed, and the
following description thereof (that is to say):-
But first I would observe, it has been found that the admission of air is
absolutely necessary to the consumption of smoke in steam engine boilers,
dying pans, brewing and other pans, furnaces, &c., and it has also been found
that if the doors or air flues are not closed in proper time, that the cold air
which continues to press in will cause the coal to consume too rapidly, and the "
boiler to wear out much sooner than if the air is partially excluded. The
object therefore of this Invention is to produce a self-adjusting or self-regu-
lating apparatus by which the door will close itself in any required space of
time, which object will be found accomplished by the following contrivance.
In some convenient part of the boiler house I place a metallic cylinder, with a
piston, the top of the rod of which is to be connected by means of a chain to
the fire door and air doors of the furnace, as shewn at Figure 1 & 2 of the
Drawing, but the interior of the cylinder and the piston is shewn in the
section, Fig. 2. A is the cylinder; B, the piston, made air-tight, with cupped
leathers, working in oil or any other anti-attritious matter (but oil I prefer),
the quantity of which should be sufficient to cover the piston when at the
bottom of the cylinder. C is the door of the fire-place and air flues, sliding up
and down in grooves, and connected as before mentioned by means of the
chain D to the piston rod, which chain passes over the pulleys E, E. When
the door C is lifted up for the purpose of putting a fresh supply of fuel into the
fire-place, the piston will descend to the bottom of the cylinder by the valve F
opening of itself as the piston descends. The door having been kept up by
means of a rest or otherwise during the time of supplying the furnace with
fuel, is now disengaged from its rest, and suspended by the chain D; the fire-
place and air passages are closed within about three inches of the bottom in
order to admit the requisite quantity of air to pass over the fire and into the
air flues; this remaining space becomes gradually closed by means of the re-
sistance which the air in the top of the cylinder exerts against the upper side
of the piston, the air being only allowed to enter under the piston by a very
small stream thro' the passage G, regulated by a stop-cock. The stop-cock is
capable of adjustment by opening and shutting, so that the aperture or passage
G for the air to pass from the upper to the under side of the piston may be
regulated according to the time in which the door is required to close the
furnace and air flues H, H, H. Thus I have described the nature of my In-

page_text: vention, which may be varied according to the size and situation of the fire-
place; the apparatus may be erected at a trifling expence, will act with little
or no attention, nor is it likely to get out of order or require reparation in many
years use.
In witness whereof, I, the said William Prichard, have hereunto set
my hand and seal, this Tenth day of February, in the year of our Lord
One thousand eight hundred and twenty-one.
Inrolled the Twelfth day of February, in the year of our Lord One thou-
sand eight hundred and twenty-one.