CERTAIN IM- PROVED MEANS OF SUPPLYING HEATED AIR IN ORDER TO SUPPORT COMBUSTION IN ENCLOSED FIRE-PLACES
Year: 1834

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I. ERNST
WOLFF, formerly of Leeds, lately of Stamford Hill, County of Middlesex, and
now of Camberwell, County of Surry, send greeting.
WHEREAS I did by petition represent to His most Excellent Majesty
King William the Fourth that I had received a commission from a certain
foreigner residing abroad of the knowledge of an Invention of "CERTAIN IM-
PROVED MEANS OF SUPPLYING HEATED AIR IN ORDER TO SUPPORT COMBUSTION IN
ENCLOSED FIRE-PLACES," and His said Majesty being willing to encourage all
useful inventions, did issue His Letters Patent under the Great Seal of Great
Britain, bearing date at Westminster, the Twenty-third day of January, in the
fourth year of His reign, whereby His said Majesty did, for Himself, His heirs
and successors, give and grant unto me, the said Ernst Wolff, Ilis especial
licence that 1, the said Ernst Wolff. my exors, admors, and assigns, or such
other persons as 1, the said Ernst Wolff. my exors, adiñors, 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 the Kingdom of Scotland, the said
Invention; in which said Letters Patent there is contained a proviso obliging
me, the said Ernst Wolff, by an instrument in writing under my hand and
seal, particularly to describe and ascertain the nature of the said Invention, and
in what manner the same is to be performed, and to cause the same to be

page_text: enrolled in His Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said 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. 1, the said
Ernst Wolff, do hereby declare that the nature of the said Invention, and the
manner in which the same is to be performed, is described and ascertained in
the manner following, that is to say:-
The Invention consists in the application to furnaces of a certain apparatus
of tubes and other parts so adapted and arranged that the atmospheric air
which is to maintain the combustion of the fuel in the fire-place is, by the
draught of the chimney. merely caused to pass within such tubes through a
suflicient extent of the chimney flue or cavity through which the beated air
from the furnace escaped, so that before it reached the burning fuel its tempe-
rature has been considerably raised. and the heat of the furnace is thereby
much less diminished than it is in ordinary cases where the combustion is kept
up by a continued accession of cold air. In describing more particularly the
arrangements of parts by which the object of this Invention is under various
circumstances intended to be accomplished, reference is made to illustrative
Drawings appended to this Specification, wherein the same parts are distin-
guished by similar letters or numbers, and the scales of proportion are marked
on the several sheets.
In Figure 1, Sheet A. is shewn the simplest arrangement by which the
object of this Invention is effected. Into the lower part of the chimney shaft
from a boiler or other closed furnace is introduced a bent tube or pipe of iron,
one extremity of which opens to the external air, the other into the enclosed
ash pit of the furnace beneath the bars which support the fuel. The shaft of
the chimney must be closed at its lower part about the two legs of the bent.
pipe, so that air cannot pass into it by any other channel than that of the flue
or fire way from the furnace. It is necessary also that the ash pit be closed
by doors or otherwise in such a way that no air can enter it but through the
inner extremity of the feed pipe fixed in the chimney. Under such an
arrangement. as a current upwards is caused in the chimney shaft. by the
rarefaction of the air passing from the furnace, the cooler external air is drawn
through the bent pipe, and becomes heated in its passage before it reaches the
furnace to support the combustion of the fuel. By these means a portion of
the heat derived from the fire, which would otherwise and does commonly
escape useless through the chimney, is imparted to the air, which is brought in to
support combustion, and is thus economised, being brought back again to the

page_text: fire-place, where it aids, to the extent of the quantity so brought back, the effect
to be produced by the fire. The heating pipes should be of as thin metal as is
compatible with economical durability, whether they be made of sheet iron or
of cast, or the upper portion of them of sheet and the lower of cast, where they
are exposed to the greatest heat. The sectional areas of the pipes may be
either circular or polygonal, but they should not be of too large dimensions.
least a portion of the air passing through them should not get heated. The
centre of the section, whatever be the form. should never much exceed three
or four inches of distance from the bounding line. The pipes may be disposed
in the chimney shaft or flue or chamber either vertically or obliquely or
horizontally, as the convenience of each case may dictate. The whole sectional
area of the pipe or pipes must not be less than that of the passages betwixt
the fire bars, as it is larger than the latter; the circulation of air through them
will be less rapid proportionally, and more heat will be therefore taken up. If
it be found that the fire bars become red hot, it may be taken as proof that a
sufficient supply of air is not obtained, and more feed pipes must be employed,
or pipes of larger diameter. It must also be borne in mind that the chimney
flue or passage must not be overcrowded with pipes, that the fire way may not
be too contracted for the passage of the quantity of air necessary to maintain
in full activity the combustion of the fuel. It has been found that a fire which
consumes 36 cwts. of coals in twelve hours requires to be fed with air through
twelve pipes of six inches diameter. The length of the heating pipes may vary
with the conveniences of the chimney or chamber, unless where it cannot be
otherwise done; they should not fall short of twenty feet in length of range
through the flue, but the greater distance they are made to traverse through
the hot air the more heat will be absorbed by the air within them. In ases
where the flue of the chimney is too contracted to admit of both the ascending and
descending legs of the syphon air pipe being introduced within it without
encroaching too much on the passage, the ascending leg of the pipe may be
kept on the outside of the chimney, and the descending leg only led down the
chimney fluc to the air chamber.
Sheet A. Figure 1, shews the application of a single heating pipe in the
chimney fue. A, chimney: B, boiler; C, outward extremity of the heating
pipe, through the aperture of which the external cold air enters; D, inner
extremity of the heating pipe, the bent end of which turns into the close ash
pit, and is embedded air-tight in the wall through which it passes, so that no
air but that which has been heated in passing through the pipe can come to
support the combustion of the fuel; E, close ash-pit. the door of which should
fit accurately to the frame, so as to prevent the ingress of air that way: F. fire-

page_text: place and flues of the boiler setting: G. flue into the chimney: H, chimney
shaft; I. bottom to close the lower part of the chimney.
Figure 2 exhibits a mode of inserting two or more heating pipes into the
same chimney. Below the place of entrance of the fire flue into the chimney
shait, a floor of stone or other fit material must be introduced, so as to cut off
from the general cavity of the chimney shaft a small chamber below, from
which must lead a passage to the ash pit. The outer extremities of the
heating pipes turned at right angles must pass through suitable openings in
the wall of the chimney, stopped around the pipes to prevent the admission of
air thereby into the chimney, and the inner extremities of the same pipes must
pass air-tight through apertures in the floor, opening themselves into the air
chamber below the floor. By this arrangement only the air from without
which has passed through the heating pipes in the cavity of the chimney can
enter the air chainber, from which it is drawn through the passage and ash pit.
to the fire-place. A, chimney; B, boiler: C, outer extremity of a heating
pipe opening through the chimney wall; D, inner extremity of the pipe opening
through the floor in the chimney into the air chamber; E. ash pit; F, fire-
place; G. flue from the boiler setting into chimney; II, chimney shaft: I, air
chamber; K, passage from air chamber to ash-pit: L, floor in the lower part
of the chimney. In this way a considerable number of heating pipes may be
introduced within the cavity of an ordinary furnace chimney, two or more being
inserted into each side wall. But where a large fire has to be maintained, it
may happen that in the chimney already built there will not be suflicient space
to dispose of an adequate number of pipes; in such cases it will be advisable
to construct an accessary chamber contiguous to the chimney. Figure 3 shews
the interior of such a chamber, with a convenient disposition of any required
number of pipes. A, chamber; B, flue from fire-place into the chimney;
C. C. external extremities of heating pipes; D. D. internal extremities of the
same pipes. passing through the floor of the chamber into the air chamber E:
F. passage from air chamber to the ash pit; G, Hoor of the chamber;
H, flue from the chamber to the chimney, the shaft of which must of course
be closed below the entrance of the chamber flue: Figure 4. horizontal
sectional plan of the lower part of the chamber and pipes. In some part of
the walling of this chamber there must be a doorway or opening capable of
being closed air-tight, sufficiently large for the introduction of the pipes and
for entrance for the purpose of occasional cleansing of the interior. This
precaution applies of course to all situations where this Invention is employed.
For the boiler furnaces of steam boats in which the economy of heat, and
consequently of fuel, is of the greatest importance, a somewhat different for

page_text: and arrangement of the apparatus now described. as applicable to stationary
furnaces, are required, in order to accommodate it to the more limited space
available on board a vessel. The air passages cannot have the same extension.
and they must be .dapted as closely as convenient to the peculiar forms of the
boiler and its connected parts. They may be described generally as either
being tubes or pipes placed within an enlarged cavity in the fire flue or chimney.
or otherwise spaces or cavities formed by a casing or jacket surrounding or
investing some portion of the chimney or fire way; various modifications may
be suggested suitable in these circumstances. It will suffice now to describe
one of cach kind.
Sheet B, Figure 1, ground plan of the boiler and hot air apparatus, shews
in section the fire flues within the boiler, and their communication with the
chimney in which are placed the pipes for heating the air. In dotted lines are
shewn the trunks which convey the heated air from the heating pipes to the
ash pit. Figure 2, longitudinal section of the boiler, chimney, and fire-
place, with the heating apparatus. Figure 3, under side of the boiler, with
the air trunks to convey the hot air beneath the fire grate. Figure 4. back
view of the chimney, with the heating pipes therein. Figure 5, front view of
boiler. half in section; the same letters mark the same parts in the several
Figures A, boiler; a, a, &c.. fire flues; b, b. b. fire-places: c, ash pit; d. fire
bars; e. steam chamber; B. chimney, spread out laterally at its lower part to
contain within it the syphon heating pipes: f. chimney flue: g. heating pipes:
1. ascending leg; 2, descending leg. The ascending legs open at the bottom
to the external air: the descending legs open at the bottom into air trunks or
cases, which passing under the bottom of the boiler and lying between the
deck beams. open upwards by rising flues into the ash pits; h. air trunks or
cases; 3, rising flues open at top. over which are 4 angular roofs or coverings
to prevent ashes falling into the air trunks. Sheet C. Figure 1, ground plan
of boiler and air passages: Figure 2, horizontal section of boiler and chimney:
Figure 3, longitudinal section of boiler and chimney: Figure 4. front view of
boiler and chimney: Figure 5, oblique front view of same; Figure 6, back
view of chimney casing and boiler; Figure 7, oblique back view of same.
The same parts are marked by the same letters in each Figure. A, boiler;
a. a. a. fire-places; b, b, b. fire flues; c, ash pit: d. fire bars; e, steam chamber;
B. chimney, flattened and extended laterally to nearly the whole width of the
boiler at its lower part. The chimney in this part is covered with a casing or
jacket on each of its flat sides. at about twelve inches distance within the space
betwixt the jacket and chimney; the air from without ascends through the
posterior cavity, and descends down the anterior one, receiving heat from the

page_text: chimney in its passage; . chimney flue; g. casing or jacket through which
the air passes; 1. ascending flue: 2. descending flue; 3. entrance apertures
for external air; C, flat trunk or case lying under the boiler. into which the
hot air passes from the chimney jacket, and is conveyed into the ash pits by as
many rising flues opening therein. These openings are each of them covered
by a hinged flap to keep out ashes, which is raised except when it is necessary
to clear out the ash pit; h, rising air flues: i. covering flaps. I claim as the
Invention communicated to nie by a foreigner residing abroad, for the intro-
duction of which into England His Majesty was most graciously pleased
to grant to me the Letters Patent to which this Specification refers. the
apparatus as now herein-before described, or variously modified according to
the circumstances under which it is to be applied. by the unassisted operation
of which apparatus the air to support combustion in an enclosed fire-place is
caused merely by the current induced by rarefaction of the air in the ascending
flue of the chimney, to pass either in pipes or chambers through or contiguous
to the space filled by the hot air from the fire, so that such fresh air becomes
considerably raised in temperature before it reaches the place where it is to
keep up the combustion of the fuel. I do not claim any of the parts mentioned
in the above description separately, but only in combination, under arrangements
similar to those now described as necessary to effect the object of this
Invention.
In witness whereof, 1. the said Ernst Wolff, have hereunto set my hand
and seal, the Twenty-second day of July, in the year of our Lord One
thousand hundred and thirty-four.
ERNST (L.s.) WOLFF.
AND BE IT REMEMBERED that on the Twenty-second day of July, in the
year of our Lord 1834, the aforesaid Ernst Wolff came before our said Lord
the King in His Chancery, and acknowledged the Specification aforesaid.
and all and everything therein contained and specified, in form above written.