IMPROVEMENTS IN AND APPARATUS FOR ECONO- MIZING THE HEAT OF OPEN FIRE-PLACES IN THE WARMING AND VENTILATING OF DWELLING HOUSES AND OTHER BUILDINGS.” PROAL SPATION
Year: 1873

page_text: LETTERS PATENT to Doctor Edward A. Crane, of 13, Rue Gaillon,
Paris, for the Invention of "IMPROVEMENTS IN AND APPARATUS FOR ECONO-
MIZING THE HEAT OF OPEN FIRE-PLACES IN THE WARMING AND VENTILATING
OF DWELLING HOUSES AND OTHER BUILDINGS.”
PROVISIONAL SPECIFICATION left by the said Doctor Edward A.
Crane at the Office of the Commissioners of Patents, with his
Petition, on the 20th September 1873.
.
I, Doctor EDWARD A. CRANE, of 13, Rue Gaillon, Paris, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN AND
APPARATUS FOR ECONOMIZING THE HEAT OF OPEN FIRE-PLACES IN THE WARMING
AND VENTILATING OF DWELLING HOUSES AND OTHER BUILDINGS," to be as
follows:
I. I construct a vertical chimney or flue of masonry, the height, width,
and depth to vary with the size of the house or appartments to be warmed,
but such as to make the flue relatively broad and shallow. I divide
this flue into three vertical compartments or shafts, see Figure 1, A, B, C,

page_text: the middle compartment A having at its summit the same width as the
lateral compartments, and at its base nearly twice that width, its walls
being proportionately thick. I close up the middle shaft A at the level
of the garret floor or roof, but permit the lateral shafts B, C, to project
through the roof, and open as chimney tops, one shaft being built
several feet higher than the other. I place in the lower extremity of
the central shaft a fire-place or grate D having a false bottom, back, and
top, between which and the walls of the shaft shall remain an air space.
In the upper part of the back of the fire-place I put the smoke outlet,
from which an iron pipe c ascends in contact with the wall separating
the shaft A from the shaft C to the closed extremity of the shaft A, at
which point it may turn into the shaft C to be continued up above the
roof. I make the wall separating the central shaft from the shaft C
relatively thin. I leave in the lateral shaft B an opening at its inferior
extremity, which shall put it in communication with the air space,
investing the false bottom and back of the fire-place or grate. I place
a perforated iron plate h, Figure 4, across the throat of the central shaft,
or at that point where the air space behind the false back of the fire-place
‘opens into the shaft, and divide the air space by a series of horizontal
metallic shelves attached alternately to the false back of the fire-place
and the back of the shaft, and open at alternate ends. I insert regis-
ters a, a, a, in the front wall of the shaft A of appropriate size, and in
appropriate numbers. Above each of these registers I put a damper
b, b, b; I insert also registers d, d, d, of appropriate size in the lateral
shaft C just below the ceiling f of each apartment through which the
FUNCTION OF THE CONSTRUCTION.
II. The room in which the fire is built in the fire-place D will be
warmed principally in the usual way, that is to say, by radiant heat.
The middle compartment or shaft of the chimney will be converted at a
the same time into a caliduct, discharging the air heated by its contact
with the false back of the fire-place, the stove, pipe, &c., into the apart-
ments where the registers a, a, a, are inserted. By means of these
registers and the dampers above the hot air can be directed into any one
of the rooms through which the shaft passes.
3
heat, which slowly given up, may regulate the evolution of heat along

page_text: its course.
The lateral shaft B is intended to furnish a supply of fresh
air, and to immediately project the same upon heated surfaces. The
lateral shaft C is designed to extract foul air from the apartments, as
also to be worked by the heat it may derive from the central shaft and
the smoke pipe.
Thus, as will be
so placed that the
The perforated plate h at the throat of the shaft A is so disposed as to
force the air which enters by the shaft B to circulate around the false
back of the grate before its escape into the shaft A. The same object is
secured also by the metallic horizontal shelves F.
seen, the chimney becomes a hot air shaft, and this is
heat which may escape through its walls, on three sides at least, is
utilised, either slightly warming the descending fresh air current
escaping directly into an apartment or accelerating the ascentional
movement in the extraction shaft. This system can be used to the best
advantage by placing two vertical chimneys constructed like the one
described back to back, see Figure 4.
In this case the heat on every
side of the hot air shafts will be utilised.
The principal advantage however to be derived from placing two sets
of flues back to back is that by causing the hot air shafts to communi-
cate one with the other at certain points the heat from both or each one of
the fire-places can be thrown into any room through which either of the
shafts may pass. Thus a fire having been built in D¹, see Figure 4, on
closing the damper 6¹ and the register a¹ in the apartment above, and
opening the registers a² and a, and closing the dampers 6 and 62, the hot
air may be deflected into the appartment E. Should there be at the
same time a fire in D the damper 62 will be left open, and the hot air
currents from both fires may be thrown into the apartment.
III. I claim that this system, of which I am the Inventor, will save
and utilise a considerable part of that heat which is now lost up the
chimney wherever open fires are used; and that it will do this,―
1st. By directing a portion of the same as hot air into the apartment
in which or the apartments above that in which the fire is built, and
where it may be of service in warming.
2nd. By moderately heating a large mass of matter (bricks, tiles, &c.)
having a high heat capacity so disposed as to give off by radiation and
conduction in a regular manner the caloric taken up, and at points were
it may be of service in warming.

page_text: 3rd. By using a portion of the heat stored up in the walls of the hot.
air shaft and a portion of the heat which may remain in the upper part
of the smoke pipe to force an ascensional current in the shaft C, where it
may be of service in ventilating.
No general principle involved in the construction may be in itself
new, but the principles never have been combined for the same object,
and in the same way. My primary object was certainly to save heat.
It was however something more than this; it was to save it in such a
way as to secure for it the most serviceable distribution as well in space
as in time.
To effect my object I have accordingly slightly changed the construc-
tion of the chimney. A. special pipe has been provided for the smoke, and
the flue is closed at its top; its masonry serves to guard the building
against the danger of fire, from sparks and incandescent gasses, but in
all other respects its functions have been completely changed, and it has
ceased to be a chimney.
Instead of a smoke flue it has become a hot air flue. Instead of a
heat dispensor it has become a heat accumulator. In short, the chimney
itself has been converted by a very simple device into a stove, which,
passing up through several floors, may warm the rooms upon each by
hot air made to circulate through it, and by heat transmitted through
its walls. The idea of thus using a chimney I believe to be novel in the
history of heating buildings. Whatever its merits may be finally proved
to be it suggests, I think, the nearest approach which has yet been made
to the realization of the old adage which, contemplating a more
perfect condition of living, informs us that "one fire should warm the
whole house."
The air, inlet, and extraction shafts. are so placed as to form essential
although subordinate parts of the heating apparatus.
The mechanism of the whole system is in this way simplified, and its
cost even cheapened. By taking the air supply from above the roof it is
drawn from a relatively pure source, and by conducting it down by the
side of the hot air shaft its temperature is raised.
The ascensional movement in the extraction shaft is created by heat
derived from the hot air shaft and by the heat of the smoke pipe, which
is thus used, and not lost,

page_text: The cost of building a flue as herein described will be little if at all
greater than the cost of building a common chimney, and the cost of
building those sufficient for the warming of a house of a given size
would be much less than the cost of constructing common chimneys for
the same house. In short, the two great objects, heating and ventila-
tion, for which fires arc or should be used in the common rooms of
dwellings will, I claim, by this system be simply, economically, and
effectually accomplished.
IV. In the statement above made I have exhibited the essential
construction of my Invention. Certain adjuncts, modifications, or
improvements which would or might increase its practical effectiveness
I shall now mention,-
1st. The downward movement of the air in the air supply shaft may
be increased by fitting to the top of the shaft a cowl made to rotate
towards the wind by a vane, see B, Fig. 2.
2nd. A similar cowl, sec C, Fig. 2, applied to the ventilating shaft, and
made to turn away from the wind, would enable us to use the aspiratory
force of the wind as an additional means of extraction. By permitting
the smoke pipe to terminate below this cowl the combustion draught
would also be increased.
3rd. Fire-places (arranged as on the first floor) may be placed in any
room through which the flue passes. These would increase the combus-
tion draught, and add to the temperature and rate of movement of the
air in the central shaft.
4th. The rate of combustion and the evolution of heat may be greatly
increased by using a heavy iron blower fitted to the fire-place.
5th. The smoke pipe of the kitchen range can be made to pass into
the extraction shaft. A motive force would be thus guaranteed summer
and winter.
6th. When the flues are placed back to back the smoke pipe of each
grate D, D', Fig. 4, may be directed downwards and backwards into the
opposite grate to enter into an oblong iron box m forming a part of the
back of the grate. The length of this box is the length of the back of
the grate, and its height and breadth vary according to circumstances.´

page_text: Its front is fluted, and it is capable of being opened at the bottom or side.
From this box the pipe is now to be returned upwards and backwards
into the hot air shaft, from which it was deflected. Short pipes n, n¹,
connect the smoke outlet of the fire-place directly with the main
ascending smoke pipe. Dampers d, d, are inserted in each short pipe 5
near the smoke outlet of the fire-place. Dampers d, d, are also inserted
in each descending branch near the same outlet.

page_text: 10th. The fresh air supply for the room in which the fire-place D is
located may be obtained through a pipe laid under the floor, one end of
which opens out of doors, and the other end opens on one side and under
the coving of the mantle. The air passing within this coving, and more
or less warmed, will escape into the room through a register inserted in
the opposite side of the mantel.
11th. A supply of air for combustion may be obtained by means of a
second pipe or air duct parallel to the one just described, and opening on
one side of the fire-place under the coving or through the hearthstone.
(The best place for the opening would be in the hearthstone, and
immediately in front of the grate; the objection to such a position'
depends upon the likelyhood of the opening soon becoming clogged with
cinders. This however could be prevented, 1st, by putting a small rim
around the opening; and, 2nd, by using an ash-pan or fender so placed as
to cover the opening and at the same time permit the air to circulate
freely beneath it towards the fire).
12th. Where only a single chimney or set of flues is used registers
may be placed in the back wall of the central shaft, and corresponding
with those in the front wall; through these the hot air from the
fire D, Fig. 1, may be directed, occasion requiring, into any room
immediately behind the shaft.
13th. The hot air in the central shaft can be directed into any rooms
adjoining those through which it passes by means of special air ducts.
14th. The extraction shaft C and the air supply shaft B may, without
affecting the system, be replaced by metallic (sheet iron, tin, or zinc)
pipes.
15th. The air supply shaft, instead of opening above the roof in close
proximity to the extraction shaft, may be turned when it reaches the
upper end of the hot air shaft, and carried a certain distance before it
emerges through the roof.
:

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Doctor Edward A. Crane in the Great Seal Patent
Office on the 19th March 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Doctor
EDWARD A. CRANE, of 13, Rue Gaillon, Paris, send greeting.
•
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of September, in the year of our
Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Doctor Edward A. Cranc, Her
special license that I, the said Doctor Edward A. Crane, my executors,
administrators, and assigns, or such others as I, the said Doctor Edward
A. Crane, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after 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 AND APPARATUS FOR ECONOMIZING THE HEAT
OF OPEN FIRE-PLACES IN THE WARMING AND VENTILATING OF DWELLING HOUSES, AND
OTHER BUILDINGS," upon the condition (amongst others) that I, the said
Doctor Edward A. Crane, 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 Doctor Edward A. Crane, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say :-
(Section I.)-In a house designed to have rooms on more than one
floor I construct a vertical chimney or flue of bricks, stone, clay pipes,
or of any suitable materials. Its height, width, and depth will vary
with the height of the house and the size of the apartments in it, but
should be such as to make the flue relatively broad and shallow. The

page_text: flue I divide longitudinally into three compartments or shafts (see
Drawing, Figure 1, A, B, C). The middle shaft (A) may have at its
summit the same width as the lateral shafts, but should have at its base
a greater width, its walls being proportionally thick. This shaft (A) is
closed up at the level of the garret floor or roof, but the lateral shafts
(B, C), project through the roof and remain open as chimney tops. The
projecting shaft C should be built several feet higher than the shaft B,
but may be several feet shorter, springing out from the side of the main
flue, as shewn in the Drawing, Figure 1. In the lower extremity of the
middle shaft I put a fire-place or grate (D) having a false bottom, back,
and top, between which and the walls of the shaft is an air space. A
metallic pipe c of appropriate size fitted to the top of the fire-chamber
ascends the shaft A in contact with the wall separating it from the
shaft C to the closed extremity of the shaft, at which point it may be
turned into the shaft C to be continued up above the roof. The wall
separating the middle shaft from the shaft C is relatively thin. In the
lateral shaft B an opening is left at its inferior extremity and below the
level of the false bottom of the fire-place, which puts it in communi-
cation with the air space, investing the false bottom and back of the fire-
place, and with the middle shaft A.
The false back of the fire-place is carried up the middle shaft a certain
distance and in such a way as to give to the smoke outlet on the top of
the fire-chamber f an infundibular form, and the air space behind it is
divided quite across by a series of horizontal metallic shelves or gills
(see Figure 3, 9, 9, 9), placed a few inches one from the other, and
attached to the false back, but open or cut short at alternate ends.
Registers a, a, a, are inserted in the front wall of the middle shaft of
appropriate size and in suitable numbers. A damper 6 is put above each
of these registers. Registers d, d, d, of appropriate size are also inserted
in the front wall of the lateral shaft C just below the ceiling G in the
rooms on the several floors of the house, these registers being the only
air inlets to the shaft C, as shown in the Drawing, Figure 1.
(Section II.) The room in which the fire is built in the fire-place D
will be warmed principally in the usual way, that is to say, by radiant
heat. The middle compartment or shaft of the chimney will be
converted at the same time into a hot air chamber by the heat coming
from the false back of the fire-place and from the metallic pipe c, which
is designed to carry off the products of combustion.

page_text: By means of the registers a, a, a, and the dampers above hot air can
be directed into rooms on each floor of the house. The brickwork or
masonry of the flue will serve also as a reservoir of heat, which given
out slowly may regulate the emission of heat along its course. The
lateral shaft B is intended to furnish a supply of fresh air and to project
the same immediately upon heated surfaces. Through the false back of
the fire-place the heat of the fire will be communicated directly to the
air drawn into the shaft A, and the horizontal shelves or gills have been
attached to it (1) to increase the heating surface (2), to reduce the
temperature of the same (3), and particularly to force the air to circulate
around and over the heated surface before passing up the shaft. The
lateral shaft C is designed to extract foul air from the rooms; as also to
be worked by the heat it may derive from the middle shaft and smoke
pipe. Thus, as will be seen, the central and principal part of the
chimney or flue becomes a hot air flue or caliduct, and this is so placed
that the heat which may escape through its walls on three sides at least is
utilized either warming slightly the descending fresh air current flowing
directly into an apartment or accelerating the ascensional movement in
the extraction shaft. This system can be used to the best advantage by
erecting the chimney so as to form a part of a partition wall separating
two rooms on each floor of the house. In this case the heat of every
side of the caliduct may be utilised.
The principal advantage however to be derived from such a position
is that by inserting registers in the back wall of the caliduct hot air can
be directed into any room through which the chimney passes. Two sets
of flues may also be erected back to back (as shewn in Figure 3). In
this case by causing the hot air flues to communicate one with the other
at certain points the heat from both fire-places may be thrown into any
room through which either of the flues may pass.
(Section III). This system, of which I am the inventor, will save and
utilize a large part of that heat now lost " up the chimney" wherever
open fires are used; and it will do this (1) by directing a portion of the
same as hot air into the apartment in which, or an apartment above that
in which the fire is built, and where it may be of service in warming;
(2) by heating moderately a mass of matter (bricks, tiles, etc.), having
a considerable heat capacity, so disposed as to give off by radiation and
conduction in a regular manner the caloric taken up, and at points where
it may be of service. in warming; (3) by using a portion of the heat

page_text: stored up in the walls of the caliduct and a portion of the heat that may
remain in the upper part of the smoke pipe to force an ascensional
current in the shaft C, and where it may be of service in ventilating.
My primary object certainly was to save heat, it was, however, some-
thing more than this, it was to save it in such a way as to secure for it
the most serviceable distribution as well in space as in time. Accordingly,
to effect my object I have slightly changed the construction of the
common chimney. A special funnel has been provided for the smoke,
and the chimney or flue is closed at the top, its masonry serves to guard
the building against the danger of fire, but in all other respects its
functions have been completely changed, and it has ceased to be a
chimney. Instead of being a smoke flue it has become a hot air flue.
Instead of being a heat dispenser it has become a heat accumulator.
In short, the chimney itself has been converted by a very simple device
into a stove, which passing up through several floors, may warm the
rooms upon each by hot air made to circulate through it and by heat
transmitted from its walls. The idea of thus using a chimney I believe
to be novel in the history of warming buildings.
The air inlet and extraction shafts are so made as to form important
though subordinate parts of the chimney. The mechanism of the con-
struction is in this way simplified, and its cost perhaps cheapened. By
taking the air supply from above the roof the air is drawn from a
comparatively pure source, and by conducting it down along the side of
the caliduct its temperature is raised.
The ascensional movement in the extraction shaft is created by heat
derived from the caliduct and by the heat of the smoke pipe, which is
thus used and not lost. In short, the two great objects, warming and
ventilation, for which fires are or should be used in the common rooms
of dwellings, can by this system be accomplished simply, effectively, and
economically.
It is not my intention in this Specification to insist upon the utility
of economizing heat in the way I propose. The general objects I have
wished to secure are evident, and their importance cannot be questioned.
But there is one advantage to be derived from a cheap and ready method
of warming and ventilating the upper and often uninhabited rooms of
dwelling houses, that although independant of questions of personal

page_text: comfort and health, is yet too important to be overlooked. A cold damp
atmosphere is very injurious to furniture.
In rooms which are rarely warmed paper hangings are liable to become
mouldy and to be detached from the walls, brass and iron work are
corroded, wood is warped and cracked, varnish loses its lustre, curtains 5
and stuffs become mildewed, bedding grows musty, articles of value are
often ruined, indeed the losses occasioned by humidity in the unfre-
quented rooms of dwelling houses are often very great. Now much of
this deterioration and loss may be prevented by warming and ventilating
these rooms in the simple way I propose. The heat transmitted through 1
the walls of the flue would generally be quite sufficient to maintain the
requisite degree of dryness.
(Section IV.)-In the preceding sections of this Specification I have
endeavoured to exhibit clearly the general construction, and the essential
principles of my Invention, and for the sake of greater clearness I have
made no allusion to certain dispositions which would or might increase
the practical effectiveness of the construction therein described.
A few of these dispositions I shall now mention, less however for the
purpose of showing how my Invention may be perfected or may be
made occasionally more efficient than with the object of stating that a
such or similar modifications would in no way affect or change the
essential principle or principles of my Invention, thus,-
1st. The extraction shaft (C) and the air supply shaft (B) may
without affecting the principle of the system be made of metal, sheet
iron, tin, zinc, etc.
2nd. The air supply shaft instead of opening above the roof in close
proximity to the extraction shaft may be turned when it reaches the
upper end of the hot air flue, and carried a certain distance before it
emerges through the roof, or instead of being vertical, and in opposition
with the hot air flue it may be horizontal and open into the air space
behind the fire place at right angles to it (see B, Figure 2). Indeed
practically a horizontal air supply shaft will probably be found to be in
a majority of cases more advantageous than a vertical one, whatever may
be the theoretical advantages of the latter.
3. The fresh air supply for the room in which the fire-place (D) is
located may be obtained through a pipe laid under the floor one end

page_text: opening out of doors, and the other end opening on one side and under
the coving of the mantel. The air passing within this coving and more
or less warmed will escape into the room through a register inserted in.
the opposite side of the mantel.
4. A supply of air for combustion may be obtained by means of a
second pipe or air duct parallel to the one just described and opening
through the hearthstone.
5. The exact form of the fire-chamber may be of no special consequence
nor may it be a matter of any consequence whether the air be forced to
circulate over a series of horizontal metallic plates or through a series of
metallic tubes, inasmuch as plates so disposed and tubes would have
similar functions.
6. The smoke pipe instead of being made of iron or other metal
may be made of earthenware; in which case it would alone serve
as a division wall between the hot air shaft A, and the extraction
shaft C.
7. Instead of turning the smoke funnel into the shaft C when it.
reaches the closed extremity of the shaft A it may be continued directly
through the plate or diaphragm closing the shaft, and in this case
the shaft A will be carried up through the roof, and the shaft C will
open above the diaphragm into the air channel in the shaft A (see
Figure 2).
8. The ventilating shaft should be divided into compartments
opening below the ceiling of each room, or metallic pipes may lead
from the inlets to a common point just below the outlet and top of the
-shaft.
9. The smoke pipe of the kitchen fire can be made to pass into the
ventilating shaft, a motive force would be thus guaranteed summer and
winter.
10. The rate of combustion can be checked by a damper at the
entrance of the smoke pipe or can be greatly increased by using a
blower or apron.
Should the room where the fire is be sufficiently
warm, and a room above be insufficiently warm fuel can be burned
with the apron down, and entirely for the service of the upper room.
11. The hot air in the shaft A can be directed into any room
adjoining those through which it passes by means of special air ducts,

page_text: 12. The hot air from a furnace in the basement or celler may be
directed into the shaft A, and be distributed by it and the special air
ducts.
13. Fire-places or stoves may be used in the rooms above the one
provided with the special fire-place D (see Figure 2, D'), and the smoke
pipe (c) of that fire-place may receive and carry off the products of
combustion from such stoves or fire-places (see Figure 2, h).
14. Any register (a) can be opened or closed, and the damper 6
above it turned by means of a mechanism that can be operated near the
fire-place D.
Having now described and particularly set forth the nature of the
said Invention and the manner of carrying the same into effect, I would
have it understood that,-
(Section V.)-I claim as my Invention a hot air flue and heat reservoir
constructed substantially as described, viz., by interposing an extensive
surface of heat conducting materials between the air chamber of the flue
and the fire-chamber of the fire-place, by providing within the flue a
special funnel for the smoke of the fire, and by closing the flue or the hot
air passage in any story above that in which the fire may be for the
purpose or purposes specified.
In witness whereof, I, the said Doctor Edward A. Crane, have
hereunto set my hand and seal, this Eighteenth day of March,
in the year of our Lord One thousand eight hundred and seventy-
four.
Witnesses,
D. H. BRANDON,
13, Rue Gaillon Paris.
P. PARBURY,
13, Rue Gaillon Paris.
EDWARD A. CRANE. (L.S.)