IMPROVEMENTS IN APPARATUS FOR REGULATING THE SUPPLY OF AIR TO. FURNACES
Year: 1870

page_text: LETTERS PATENT to Thomas Symes Prideaux, of 209, Piccadilly,;
in the County of Middlesex, Engineer, for the Invention of,
"IMPROVEMENTS IN APPARATUS FOR REGULATING THE SUPPLY OF AIR TO.
FURNACES."
Sealed the 24th January 1871, and dated the 11th August 1870.
PROVISIONAL SPECIFICATION left by the said Thomas Symes Prideaux
at the Office of the Commissioners of Patents, with his Petition,
on the 11th August 1870.
I, THOMAS SYMES PRIDEAUX, of 209, Piccadilly, in the County of
Middlesex, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN APPARATUS FOR REGULATING THE SUPPLY OF AIR TO
FURNACES," to be as follows:-
.
The object of this Invention is to afford furnaces an additional supply.
of air after cooling, which supply shall gradually diminish and even-
tually cease after a certain definite period of time by the action of an
automatic apparatus, thus securing the cutting off of the additional

page_text: -
The apparatus consists of two parts, —
First. A case or air chamber in the exterior of the furnace furnished
with a cover or shutter moving on a hinge or axle, so as to admit or
exclude the air at pleasure, and communicating with the interior of
the furnace through the fire-door and two channels placed laterally, the
exit mouths of these passages being furnished with grating suitable for
heating and distributing the air as it passes into the furnace and at
the same time preventing the radiation of heat outwards.
Secondly. A motor regulator by which the gradual closing of the
shutter of the air chamber is automatically effected. This motor regu-
lator consists of, 1st, a cylindrical cup or cistern pierced with a small
orifice at the bottom and having a rod rising from its centre; 2dly, of
a cast-iron cylinder of about twice the depth of the cistern, of such a
diameter as to admit of the cistern traversing freely within it, having a
solid cylindrical block attached to the under side of the cover pierced in
the centre for the passage of the cistern rod, which block is to be of a
diameter as much less than the interior of the cistern as will allow of
its entering it, thus enabling the cistern to be raised to the top of the
cylinder. A few small vertical grooves are to be cut on the interior of
the cylinder & the exterior of the cylindrical block to facilitate the
passage of the mercury with which the apparatus is worked, as follows:-
The cistern being filled with mercury and placed at the bottom of the
cylinder and the cylinder cover screwed down, upon raising the cistern
by means of its rod (which projects through the cylinder cover) to the
top of the cylinder, the cylindrical block or plunger enters the cistern,
causing the mercury to flow over its sides and pass through the grooves
to the bottom of the cylinder. The raising of the cistern rod lifts and
opens the shutter (or shutters) to which it is attached by a link and
pin joint, whilst the weight of the shutter slightly depressing the
cistern causes the mercury to rise in the grooves and sides of the
cylinder considerably above the level of the bottom of the cistern, and
as a consequence to flow into the cistern through the small orifice in
its bottom causing it gradually to descend and the shutter to close in
a time proportionate. to the size of the orifice and the area of the
cistern

page_text: Where practicable I prefer to carry out my Invention as above
described, but in cases where the projection of this apparatus beyond
the face of the furnace shall be deemed inadmissible or inconvenient, I
substitute an apparatus as follows:-In place of forming the face of the
furnace door of a series of louvres or shutters, as in my Patent of the
27th of December, 1853, I construet it mainly of one wide shutter
having a deep recess or furrow down the middle which gradually becomes
shallower as it approaches the top & bottom where it reaches the surface,
so that the continuity of the horizontal lines forming the edges of the
shutter remains unbroken. In the recess thus formed I fix rigidly, so
as to form a constituent part of the shutter with no motion independent
of that derived from the motion of the shutter on its axle, a vessel
containing quicksilver somewhat in the shape of a capital D; when the
shutter is closed the quicksilver is contained in a reservoir at the bottom,
upon. opening the shutter it passes instantly along the chord of the
are into a reservoir at the opposite end where it keeps the shutter open
by its weight, till gradually passing out of it through a small orifice in
its bottom it traverses the curved or lower level passage & eventually
enters the reservoir from which it started, the shutter having gradually
closed in the interim. The recessed portion of the shutter is to bo
defended from the radiant heat of the furnace by a non-conducting shield
consisting of a case of sheet iron filled with cinder dust or some other
bad conductor. The admission of air is not to be confined to the breadth
of the doorway, where this is much narrower than the grate-bars,- but
chambers with grated faces are to be constructed on the dead plate at the
sides of the doorway & supplied with air by means of openings at the
sides or bottom of the door.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Symes Prideaux in the Great Seal Pätent.
Office on the 7th February 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
SYMES PRIDEAUX, of 209, Piccadilly, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
5 Letters Patent, bearing date the Eleventh day of August, in the year of

page_text: our Lord One thousand eight hundred and seventy, in the thirty-third
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Thomas Symes Prideaux, Her special licence that
I, the said Thomas Symes Prideaux, my executors, administrators, and
assigns, or such others as I, the said Thomas Symes Prideaux, my exe-
cutors, 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 APPARATUS
FOR REGULATING THE SUPPLY OF AIR TO FURNACES," upon the condition
(amongst others) that I, the said Thomes Symės Prideaux, my executors
or administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, 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 Patent.
NOW KNOW YE, that I, the said Thomas Symes Prideaux, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement:-
The object of this Invention is to afford furnaces an additional
supply of air after coaling, which supply shall gradually diminish, and
eventually cease after a certain definite-period of time by the action of
an automatic apparatus, thus securing the cutting, off of the additional
supply of air when no longer required, independently of the attention
of the fireman.
The apparatus consists of two parts,—
First. A case or air chamber on the exterior of the furnace (Fig. 3, a)
furnished with a cover or shutter (6) moving on a hinge or axle, so as
to admit or exclude the air at pleasure, and communicating with the
interior of the furnace through the fire-door and two chambers placed
laterally, the exit mouths of these passages being furnished with grating
(Figs. 4 & 5, c) suitable for heating and distributing the air as it passes
into the furnace, and at the same time preventing the radiation of heat
outwards.

page_text: Secondly. Of a motor regulator, by which the gradual closing of
the shutter of the air chamber is automatically effected. This motor
regulator consists of, 1st, a cylindrical cup or cistern (Fig. 1, d,) pierced
with a small orifice (e) at the bottom, and having a rod (ƒ) rising from
its centre; secondly, of an iron cylinder rather more than twice the
depth of the cistern, of such a diameter as to admit of the cistern
traversing freely within it, having a cylindrical block (h) attached to
the under side of the cover pierced in the centre for the passage of the
cistern rod, which block is to be of a diameter as much less than the
interior of the cistern as will allow of its entering it freely, thus enabling
the cistern to be raised to the top of the cylinder. A few small vertical
grooves (Fig. 2, i,) are to be cut on the interior of the cylinder and on
the exterior of the cylindrical block to facilitate the passage of the
mercury with which the apparatus is worked as follows:-The cistern
being filled with mercury and placed at the bottom of the cylinder, and
the cylinder cover screwed down, upon raising the cistern by means of
its rod which projects through the cylinder cover to the top of the
cylinder, the cylindrical block or plunger enters the cistern, causing
the mercury to flow over its sides and pass through the grooves and
the circumferential instertice between the cistern and the sides of the
cylinder to the bottom of this vessel. The raising of the cistern rod
lifts and opens the lid or shutter, to which it is attached by a link and
pin joint, whilst the weight of the shutter slightly depressing the cistern
causes the mercury to rise in the grooves and round the sides of the
cylinder considerably above the level of the bottom of the cistern, and
as a consequence to flow into the cistern through the small orifice in its
bottom, causing it gradually to descend, and the shutter to close in a
time proportionate to the size of the orifice and the area of the cistern.
Where practicable I prefer to employ the apparatus described, but in
cases where the projection of this apparatus beyond the face of the
furnace shall be deemed inadmissible or inconvenient, I substitute an
apparatus as follows:-In place of forming the face of the furnace door
of a series of shutters, as described in my Patent of the 27th December
1853, I construct it mainly of one wide shutter, having a deep recess or
furrow (Fig. 6, k,) down the middle, which gradually becomes shallower
as it approaches the top and bottom of the shutter, where it reaches the
level of the lateral plane surface (1), so that the continuity of the hori-
zontal lines forming the edges of the shutter is preserved. In the recess

page_text: Figure 1 shows a section of the motor regulator constructed according
to my Invention, and Fig. 2, a section of the same through the line A, B.
The same letters indicate the same parts in all the Figures; d, represents
the cistern; g, the cylinder; h, the plunger, and e, the small hole in
the cistern, by which the mercury enters causing it to descend; f, the
¿cistern rod, and i, i, i, the small vertical grooves on the interior of the

page_text: cylinder and the exterior of the plunger for
mercury.
Figure 3 shows a front view of an apparatus applied to the mouth of
a furnace constructed according to my Invention; Figure 4 is the same in
section, and Figure 5 is a back view of the same seen from the interior
of the furnace; a, shows the exterior air case divided into three chambers
or passages; b, the cover attached by a link seen at j to the cistern rod
of the motor regulator g placed in the right-hand chamber. The cover
may either be opened by the fireman when he closes the door after
coaling or made self-opening by the aid of a segment of a screw attached
to the hinge of the furnace door c, the grating dividing the air chambers
from the fire, and which becoming highly heated during the time the
shutter is closed imparts this heat to the entering current of air during
the time the apparatus is in action; w, a screen or shield for protecting
the cylinder of the regulator from the heat radiated from the fire; t, t,
two plates of sheet iron with vertical slits or openings so placed that the
intervals shall not correspond to assist in preventing the radiant heat
from reaching the front of the door; s, the dead plate.
Figure 6 shows a vertical section of the self-closing shutter described
in the text, (forming about the lower two-thirds of the face of the
furnace door) in the position it occupies when closed; k is the central
recessed portion meeting at 1, 1, the plane surface of the lateral portion,
indicated by the dotted lines, the axle upon which the shutter turns
being indicated in the middle of the dotted lines by u; m, the mercury
chamber. The mercury being in the reservoir n, upon opening the
shutter till the passage o acquires a horizontal position the mercury
rushes into the reservoir p, where it keeps the shutter open by its weight,
but gradually passing through the small hole q it slowly traverses the
curved passage », retarded in its motion by the little stops v, v, v, till it.
finally re-enters the reservoir n from which it started, the shutter having
gradually closed during the processs.
Figure 7 is a section of a furnace door constructed according to my
Invention, showing the position of the cylinder when in default of space
for lateral air chambers, I place the cylinder regulator in the face of the
fire-door itself, w, represents a non-conducting shield consisting of a case
of sheet iron filled with cinder dust or some other bad conductor, the
office of which is to protect the cylinder from the radiant heat of the
fire

page_text: I have now described the nature of my Invention and the mode in
which it is to be accomplished, I do not however confine myself to the
precise mechanical details provided the principles be carried out, but
what I claim is,―
First. The motor regulator described and shown in Figs. 1 and 2.
Second. The combined arrangement of furnace door and air chambers
described and shown in Figs. 3, 4, & 5, when used in combination with
an apparatus for gradually shutting off the ingress of air.
Third. The constructing of the front of a furnace door in the manner
herein described and shown in Figure 6.
In witness whereof, I, the said Thomas Symes Prideaux, have here-
unto set my hand and seal this Seventh day of Fahmen
101
T. SYMES PRIDEAUX. (L.S.)