IMPROVEMENTS IN APPARATUS POR BURNING ANIMAL CHARCOAL
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by James Bolton at the Office.
of the Commissioners of Patents, with his Petition, on the 9th
December 1868.
I, JAMES BOLTON, Managing Director of the Avonside Sugar Refinery
Company (Limited), Bristol, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN APPARATUS POR BURNING ANIMAL CHARCOAL,"
to be as follows:-
This Invention has for its object improvements in apparatus for-
burning animal charcoal.
The revolving iron retorts now in use for burning animal charcoal
have mostly complicated internal arrangements for carrying the char-.
coal forward, and which in some cases detract very much from the
soundness and durability of the casting, at the same time adds to the
cost. The method of arranging and heating the retorts is also imperfect..
The object of my Invention is to obtain a simpler, more durable, and
cheaper mechanism, and also greater efficiency in working.

page_text: According to my Invention I make the retorts conical and mount
them with their axes horizontal. By this the charcoal is carried forward
continuously by the simple revolution of the retort without internal
mechanism.
I also in some cases make the retorts with corrugations lengthways, by
which means a much larger amount of metallic heating surface is
obtained, and the charcoal which is itself a bad conductor of heat is
consequently more uniformly heated. In some cases, in order to increase
the heating surface, I place inside an otherwise plain retort a number
of ribs or shelves running lengthways of the retort and radiating from
the centre; such ribs also give increased strength to the retort. Or I
place the shelves at such an angle as to pick up the charcoal and retain
it at the side of the retort as it rises after being exposed to the full heat
of the fire, so that a greater portion of the circumference of the retort
is caused to act efficiently as heating surface.
In order to carry the charcoal forward along the retort (especially
where the retort is cylindrical and mounted horizontally) I sometimes.
in place of making the ribs of the same width from end to end of the
retort make them to taper and become narrower towards the end where
the discharge is to take place; or, by preference, I form the edge of the
rib into a number of saw-like teeth, whereby I obtain a much greater
amount of incline. The charcoal forms heaps with inclined sides on
the teeth as they rise up in the rotation of the retort, and the upper
part of the heap as the motion continues rolls down the inclined sides,
and so the traverse of the material along the retort is obtained; also I
make the retorts in two or more lengths or parts, so that defective or
burnt parts may be replaced instead of having the expense of an entirely
new retort. I sometimes support the retort by means of a hollow axis
passing through it from end to end, and I keep the axis cool by causing
air or water to circulate through it; also in some cases I place the
furnace or furnaces at the side of the structure containing the retorts,
and lead the flues circumferentially around them, so a greater and more
regular heat may be maintained than by firing longitudinally as is now
the practice, and the charcoal is better and more quickly burnt, the
retorts also last longer.
By arranging the furnaces in this manner I am enabled to provide a
central support underneath the retort, which enables it better to support

page_text: its weight and the weight of the charge and the heat to which it is
exposed. It also enables me to employ retorts of fire-clay, which cannot
be done when the retort is unsupported in consequence of the great
weight. The retort is made in sections or lengths and provided with
metal ends.