IMPROVEMENTS IN OR CONNECTED WITH THE FURNACES OR HEATING APPARATUS OF RETORTS AND STILLS FOR OBTAINING OR TREATING MINERAL OILS OR GAS, AND ALSO APPLICABLE TO STEAM BOILERS AND TO OTHER BOILERS OR EVAPORATING VESSELS
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by John Calderwood and William
McCutchon at the Office of the Commissioners of Patents on the 2nd August
1878.
JOHN CALDERWOOD, Manager, and WILLIAM MCCUTCHON, Engineer, of the
Addiewell Chemical Works, West Calder, in the County of Mid Lothian, North
Britain. "IMPROVEMENTS IN OR CONNECTED WITH THE FURNACES OR HEATING
APPARATUS OF RETORTS AND STILLS FOR OBTAINING OR TREATING MINERAL OILS
OR GAS, AND ALSO APPLICABLE TO STEAM BOILERS AND TO OTHER BOILERS OR
EVAPORATING VESSELS."
This Invention has for its object to obtain increased efficiency, with uniformity of
action, economy of materials, utilisation of hitherto wasted heat, and diminution of
smoke from the fuel employed for heating the retorts or stills used for obtaining or
treating mineral oils or gas, and the improvements are also applicable to steam
boilers and to other boilers or evaporating vessels.
The
In carrying out the Invention the gaseous products of combustion or fire gases, as
they are herein-after briefly termed, after operating on the retorts, or stills, or
boilers, or other vessels, are led through flues so as to utilise a large part of the
heat remaining in them in heating the fresh coal in retorts, or kilns, or ovens.
heat thus applied to the fresh coal causes the evolution therefrom of hydrocarbons
or combustible vapors or gases, and these are led into the furnace or combustion
chamber, whilst the residuary coal or coke is transferred from the retorts, kilns, or
ovens also to the furnace in either a continuous or intermittent manner..
The coke rests on grate bars in the furnace, and the air for its combustion is
supplied beneath those bars, whilst air for the combustion of the gases or vapors
from the fresh coal is introduced at suitable points above the bars. The air thus
supplied is, by preference, heated by passing through flues formed in the sides of the
furnace or contiguously to the fire-gas flues.
The apparatus used in carrying out the Invention may obviously be constructed
and arranged in a great variety of ways.
In one modification a vertical cylindrical retort of cast iron is employed for the
fresh coal which is introduced at the top through a valved conical inlet.

page_text: The retort is encased in brickwork in which flues are formed encircling the retort
in a spiral or other suitable manner, the otherwise waste fire gases entering such
flues, by preference, near the bottom of the retort, and finally passing off from the
upper part by a flue leading to the chimney.
As the coal is being acted on by the heat it gradually descends in the retort, the
residuary coal or coke finally dropping from the bottom end of it into a space or
passage leading into the furnace, and from which it may be periodically pushed into
the furnace by means of a stoking iron; or the coke may pass automatically down
an inclined plane into the furnace.
The hydrocarbons or combustible vapors or gases evolved from the coal whilst in
the retort may either pass downwards through the coal in the retort and proceed
from the bottom of the retort directly into the furnace, or a pipe or pipes may be
connected to the upper or other suitable part of the retort to lead them into the
furnace. With these arrangements the coal in its passage down through the retort
is first completely dried and then partially distilled or carbonised, so that when it
reaches the bottom of the retort it is in a heated state, and has by that time parted
with a considerable proportion of its volatile bydrocarbons which have been
gradually consumed as they reached the furnace. In this way the furnace is
maintained at a uniform temperature and the hydrocarbons are not given off, as in
ordinary furnaces, at a rate too rapid for their complete combustion.