IMPROVEMENTS IN THE CON- STRUCTION OF CLOSE,' 'BLIND,' OR 'MUFFLE SALT CAKE, OR OTHER SIMILAR FURNACES
Year: 1876

page_text: LETTERS PATENT to Henry Deacon, of Appleton House, Widnes, in the
County of Lancaster, for the Invention of "IMPROVEMENTS IN THE CON-
STRUCTION OF CLOSE,' 'BLIND,' OR 'MUFFLE SALT CAKE, OR OTHER SIMILAR
FURNACES."
'
Sealed the 10th March 1876, and dated the 17th January 1876.
PROVISIONAL SPECIFICATION left by the said Henry Deacon at the Office
of the Commissioners of Patents on the 17th January 1876.
HENRY DEACON, of Appleton House, Widnes, in the County, of Lancaster.
"IMPROVEMENTS IN THE CONSTRUCTION OF 'CLOSE,' 'BLIND,' OR 'MUFFLE SALT
CAKE, OR OTHER SIMILAR FURNACES."
This Invention relates to "close," or "blind," or "muffle "salt cake and other similar
furnaces, and consists in placing the fire, which is contiguous to the furnace, so low
in relation to the "muffle" that the ascending power of the column of hot air over
the fire is sufficient so to propel the flame, &c., through the flues round the "muffle,"
as to prevent the escape of gas from the "muffle" into the "flues."
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Deacon in the Great Seal Patent Office on the 8th July
.1876.
HENRY DEACON, of Appleton House, Widnes, in the County of Lancaster.
"IMPROVEMENTS IN THE CONSTRUCTION OF CLOSE, BLIND,' OR 'MUFFLE'
SALT CAKE, OR OTHER SIMILAR FURNACES."
My said Invention relates to "close," or "blind," .or 'muffle" salt cake and
other similar furnaces, and consists in placing the fire which is contiguous to the
furnace so low in relation to the muffle that the ascending power of the column of
hot air over the fire is sufficient so to propel the flame and other products of com-
bustion through. the flues round the "nuffle," as to prevent the escape of gas from
the "muffle" into the flues, that is to say, I place the furnace on the top of or
higher than the chimney, whilst according to the usual construction the chimney
is placed upon or higher than the furnace, the term "chimney" being here used to
[Price 6d1

page_text: designate the shaft containing the heated column of air required to produce the
difference of atmospheric pressure or "draft" necessary for the combustion of the
fuel and for the propulsion of the flame and other products of combustion through
the furnace I place this chimney" directly over the fire where it is very hot and
where leakage of unnecessary air into it may easily be prevented. A chimney so
constructed in comparison with ordinary chimneys is very powerful in proportion
to. its height. By these means I preserve what is termed "plus" pressure in all
the flues, so that leakage, if any, takes place from the flues to the muffle and not vice
versa, I have found a vertical height of from six to eight feet from the fire-bars to.
the outlet below the muffle usually sufficient, but the smoke issuing from this outlet
can seldom, if ever, be discharged directly into the air, and must be conveyed by
other flues or passages into an ordinary chimney, and the draft from this ordinary
chimney should be prevented from affecting in any material degree the plus
pressure in the furnace flues.
or
I prefer an ordinary chimney with an ample capacity but with a draft of feeble
intensity and considerable regularity, and when such a chimney is employed I
make connections with the external atmosphere by means of large "breaks"
openings situate betwen the outlet of the furnace and the ordinary chimney flue
leading to it, the several Figures on the annexed Sheet of Drawings illustraté
one mode of construction which I shall now proceed to describe by the aid of
the letters of reference, the same letters indicating corresponding parts in all the
Figures.
Figure 1 of my Drawings represents a longitudinal section of a muffle furnace,
constructed and arranged according to my Invention.
Figure 2 is a transverse section taken through the muffle and pot.
Figure 3 is a longitudinal developed section taken through the lower part of the
muffle, through the pot and the smoke flue along the line 1, 2, 3, 4, Figure 5.
Figure 4 is a sectional plan, the section being taken through the muffle.
Figure 5 is a sectional plan taken through the muffle sincke flues, pot smoke
flues, and chimney smoke flues.
Figure 6 is a transverse section taken through the bye flue along the line 5, 6,
Figure 5.
It will be unnecessary, to describe the whole of the parts in detail, as their use
and mode of operation will be obvious to practical men.
R is the muffle or close roaster.
S, the pot.
T, the grate roo
U, the chimney or column of hot air, causing the draft or propelling power of
the furnace.
D
V, the smoke flues.
W, the acid gas outlet.
X, a bye flue for conveying the 'waste heat to the ordinary chimney when
the heat is not wanted under the pot..
YY, the openings communicating with the air.
Z, the ordinary smoke chimney Blues.
The pot can be set with the brick or other cover inside its rim, and the rim
itself can be exposed to the outside air throughout, so that leakage of gas from the
pot to, the flues being impossible, the maintenance of a "plus" pressure under the
pot is unnecessary. I prefer therefore to treat the pot and roaster as two pieces
of apparatus-and-make-two-breaks or large openings_communicating with the
external atmosphere in the fire flues, one of these breaks being between the
roaster, and the pot and the other between the pot and the smoke chimney damper,
both breaks being as close to the pot as conveniently may be.
I prefer that the air admitted over the fire should be deficient in quantity and
be in large inasses, so that it may mix slowly and prolong the duration of com-
bustion in the flues.
The two breaks are shewn at Y, Y, and with this arrangement the smoke

page_text: with the other products of combustion leaving the roaster flues are easily kept
deficient of air, and air entering at the break between the roaster and pot assists
in burning the unconsumed fuel gases under the pot. At Y' the heavy cold air
enters at the top amidst the hot smoke to assist diffusion and help to complete the
imperfect combustion within a short distance from the opening, that is to say, under
the pot Y allows the cold air to enter at the bottom of the flue where the object is
to carry off the upper stratum (hot air) only. For obvious reasons the air openings
Y and Y are arranged as near the pot, and the chimney damper is placed as far
from the pot outlet as possible. If the draft of the flue Z when dampered off
is fully fed and is sufficient to draw some air at Y, and necessarily more air at Y,
then if a little more smoke than before escapes or is propelled from the furnace òr
if the chimney draft of the flue at Z diminishes as by lowering the damper, then
smoke will escape at Y', but if a little less smoke than before escapes or is propelled
from the furnace, or if the draft of Z increases as by raising the damper, then
air will enter chiefly at Y and restore the equilibrium, and in each case there will
be a minimum amount of disturbance both to the draft' or propelling power of
the column of heated air over the fire and to the plus pressure in the flues of
the furnace, I prefer that the damper to the ordinary chimney be as small as
possible so that if the damper be completely raised the "plus" pressure in the flues
of the muffle is not wholly destroyed.
Having now described and particularly ascertained the nature of my said In-
would observe in
vention, and one mode of using it or carrying it into effect,
conclusion that I do not confine myself to the precise arrangement shewn in the
Drawings and herein-before described, as the same may be modified in many ways
and applied to other descriptions of furnaces, and that I do not claim the mere
placing of the fire below the level of the muffle or furnace, but what I consider
to be novel and original and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent is, constructing "close," or "blind," or
muffle" salt cake and other similar furnaces, in such a manner that the fire which
is contiguous to the furnace is placed so low in relation to the muffle that the
ascending power of the column of hot air over the fire is sufficient so to propel tho
flame and other products of combustion through the flues round the muffle as
to prevent the escape of gas from the muffle into the flues, substantially as
herein-before described.
In witness whereof, I, the said Henry Deacon, have to this my Specification
set my hand and seal, the Fourth day of July, One thousand eight hundred
and seventy-six.
HENRY DEACON. (L.S.)