IMPROVE- MENTS IN THE CONSTRUCTION OF HOT AIR APPARATUS FOR WARMING BUILDINGS AND OTHER STRUCTURES
Year: 1875

page_text: LETTERS PATENT to John Ford Mackenzie, of Quadrant Chambers,
Wigan, in the County of Lancaster, for the Invention of “IMPROVE-
MENTS IN THE CONSTRUCTION OF HOT AIR APPARATUS FOR WARMING BUILDINGS
AND OTHER STRUCTURES."
Sealed the 25th June 1875, and dated the 11th January 1875.
PROVISIONAL SPECIFICATION left by the said John Ford Mackenzio
at the Office of the Commissioners of Patents, with his Petition,
on the 11th January 1875.
I, JOHN FORD MACKENZIE, of Quadrant Chambers, Wigan, in the
County of Lancaster, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN THE CONSTRUCTION OF HOT AIR APPARATUS FOR
WARMING BUILDINGS AND OTHER STRUCTURES," to be as follows :-
Certain portions of the shell of the cast-iron stove or apparatus are
constructed in the form of a series of hollow pyramids or cones. The
heat and flame from the furnace impinging upon the internal, hollow, or
concave sides of these projections, and cold air upon the external face of

page_text: the raised or convex portions. The flame and heat from the furnace
being also arranged to pass into a chamber intersected by hollow cast-
iron flues or passages which convey cold air to be heated through the
apparatus, these flues and passages being either square, oblong, or of
other suitable section, and internally constructed with ribs or flanges
protruding inwards and with or without corresponding grooves externally.
From this flue chamber the smoke and other products given off by the
burning fuel pass by means of one or more outlets into the smoke flue of
the apparatus.
Between the chamber containing the stove and, the passages which
convey away the heated air from the apparatus into the building to be
warmed a perforated screen or mid-feather is erected, so constructed of
firc-clay as to present a large surface of that material to the action of
the heated air. On that side of this screen furthest from the stove is a
fluc connected with the external air, with a valve or damper to regulate
the admission of a current of cold air when required, to incorporate with
the heated air previous to its introduction into the apartment intended
to be warmed.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Ford Mackenzie, in the Great Seal Patent
Office on the 10th July 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
FORD MACKENZIE, of Quadrant Chambers, Wigan, in the County of
Lancaster, send greeting.
:
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of January, in the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said John Ford Mackenzie, Her
special licence that I, the said John Ford Mackenzie, executors,
administrators, and assigns, or such others as I, the said John Ford
Mackenzie, my executors, 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,

page_text: 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 THE CONSTRUCTION OF HOT AIR APPARATUS FOR WARMING
BUILDINGS AND OTHER STRUCTURES," upon the condition (amongst others)
that I, the said John Ford Mackenzie, 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 John Ford Mackenzie, 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 :—
This apparatus, as shewn by the accompanying Drawings, consists of
the following parts or sections, viz. :-A, the furnace or fire-box; B, ash
box underneath furnace; C, flue chamber; D, intersecting flues for
conveying pure air through the apparatus; E, smoke flues; F and O,
cold air inlets or flues; G, perforated screen or mid-feather of fire-clay;
H, outlets for warmed air; I, ventilators or dampers; J, hot-air closet;
K, pyramidical projections on surface of iron casing.
The furnace A is of cast iron lined with fire-brick, or it may be of
iron fire-bars simply built into brickwork, and is placed within the flue
chamber C, but on a lower level than the bed of that chamber, the top
of the furnace being on a level with the bed plate of the flue chamber.
By the ventilating doors or dampers I the draught of the fire is regulated
at pleasure by opening or shutting them as may be required. The feed
door may be placed either above the furnace, as shewn at L, or on a
lower level, as circumstances may direct.
On any one side or both sides, or at one end or both ends, or all:
round the furnace, a flue chamber C is constructed upon a level with the
upper part of the furnace. This flue chamber may be entirely con-
structed of fire-clay quarries and fire-bricks, with suitable openings to
receive the intersecting flues, or partly of fire-clay and partly of iron, or
as shewn by the Drawings, entirely of cast iron, or it may be made of
wrought iron or of an union of any or all of these materials, For,

page_text: instance, the bed or lower plate of the chamber may be made of fire-clay
quarries, the sides and ends built of fire-brick, and the upper portion of
either cast or wrought iron or other convenient arrangement. The
object of this chamber being to provide an enclosed space or oven into
which the flame and hot gasses from the furnace will pass before
reaching the smoke flue of the apparatus for the purpose of heating a
series of tubes or flues which intersect the interior of this chamber.
From the flue chamber the smoke and other products given off by the
burning fuel pass away by means of one or more outlets into the smoke
flue E of the apparatus. A damper or valve should be fitted in the smoke
fluc to regulate the draught of the furnace and a soot door provided as
at P for cleaning the interior of the fluc. The smoke outlets N being so
placed that the flame and hot gasses cannot leave the flue chamber
without first circulating between the intersecting flues, and thereby
warming them. The hot flues warm the cold air circulating through
them.
When the sides, back, front, ends, or upper portion of this fluc
chamber C is constructed of iron the shell or casing thus formed may be
utilised as a heating and radiating surface, as shewn by the accompany-
ing Drawings, and in the case of cast iron being used any portion of this
casing may be constructed in the form of a series of hollow pyramids or
cones K, the heat and flame from the furnace impinging upon the
internal hollow or concave sides of these projections, and cold air upon
the external raised or convex portions. By the introduction of these
pyramidical projections the extent of radiating surface is very con-
siderably increased.
When wrought or cast iron is used in conjunction with firc-clay
quarries, or wrought iron in conjunction with cast iron, or when cast
iron is used alone for the casing, bed, or other portions of the apparatus,
the horizontal joints as at M should be very carefully luted in such a
manner as to make an air-tight joint, and allowing also for the expansion
and contraction of the metal. For this purpose a luting of powdered
chalk, with an upper coating of sand or iron filings, or a mixture of
chalk with sand or iron filings may be used. The sand or iron filings is
used as a weight to retain the chalk in its place in the cavity forming
the joint.
The intersecting flues or air passages D which pass through the flue
chamber C are open at both ends, one end being connected with the cold

page_text: air inlet F, which conveys pure air from the outside to the apparatus, and
the other end with the hot-air closet J. These flues or air passages may
intersect or cross the flue chamber C. in a straight, curved, twisted,
vertical, horizontal, or angular manner or in any direction most con-
venient for heating them by bringing them into contact with the flame
and heat of the furnace, care being taken in the arrangement not to pass
them through the fire nor to place them in any position where they
would be superheated, and the air circulating through them thereby
become burnt and unfit for respiration. These flues D may be constructed
either of cast iron, as shown by the Drawings, or of wrought or malleablo
iron, or of copper or brass, or of any two or more of these metals, and
may be either square, oblong, or of other suitable section, and internally
constructed with ribs or flanges protruding inwards and with or without
corresponding grooves externally; these ribs or flanges being either
straight or spiral shaped, or both, and extending from end to end of
cach tube or flue. All horizontal joints or junctions as at M to be luted
as before described.
An ash box B is placed under the furnace. This box may either be con-
structed either of cast iron, as shewn on Drawings, or built of brickwork,
with an iron door fitted in. In this door a ventilating damper is placed.
for regulating the draught in the furnace.
The whole of the apparatus stands upon a flag or brick floor, and is
enclosed within an outer casing of brickwork covered by fire-clay
quarries Q, or by a brick arch, as circumstances may direct, the interior
of this casing forming a hot-air closet J, from which tubes or passages
H convey away the heated air in any required direction to the building
or other structure intended to be warmed. To filter or purify the heated
air it is passed through an occlusior or perforated screen G erected as a
mid-feather within the hot-air closet J, as shewn, or at any point between
the flue chamber C and the warm air outlets H. This screen may be
formed of wire netting fitted to cach side of an iron framework, and
filled in between with broken chips of burnt fire-clay of a light porous
quality, or it may be formed of a series of narrow shelves or trays of
wire netting placed one over the other, and each tray containing small
broken chips of burnt fire-clay. On the outlet side of this fire-clay
screen a special current of pure cold air is introduced,-
,-as shewn at O.
This inlet is regulated by a valve or damper. By this means, when
required, any proportion of cold fresh air can be incorporated with the

page_text: L
warm air in its passage from the apparatus, and the velocity of the
currents of air entering the building increased as may be desired.
The following is a summary of the points claimed as the Invention by
the Patentee :-
:-
1st. A distinct flue chamber and its position as regards the furnace of
the apparatus.
2nd. The construction of pyramidical or cone shaped hollow pro-
jections upon the surface of the case or covering of the flue chamber.
3rd. The use of intersecting flues or air passages having internal ribs
or flanges.
4th. The perforated fire-clay screen or hot-air occlusior.
5. The introduction of a distinct current of cold air into the hot-
air closet after the heated air has passed the warming apparatus.
In witness whereof, I, the said John Ford Mackenzie, have here-
unto set my hand and seal, this Ninth day of July, in the year
of our Lord One thousand eight hundred and seventy-five.