IMPROVEMENTS IN TREATING VAL-DE-TRAVERS' ROCK AND OTHER LIKE MINERAL SUBSTANCES FOR THE PURPOSE OF REDUCING THE SAME TO POWDER, AND IN MACHINERY OR APPARATUS EMPLOYED FOR THAT PURPOSE
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by James Harcourt Ivory at the
Office of the Commissioners of Patents, with his Petition, on the
20th February 1873.
$
I, JAMES HARCOURT IVORY, of Birmingham, in the County of
Warwick, Civil Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN TREATING VAL-DE-TRAVERS' ROCK AND
OTHER LIKE MINERAL SUBSTANCES FOR THE PURPOSE OF REDUCING THE SAME TO
POWDER, AND IN MACHINERY OR APPARATUS EMPLOYED FOR THAT PURPOSE," to be
as follows:-
.
The said "Val-de-Travers" rock is a bituminous limestone largely used
for paving. In applying it to this purpose it requires to be reduced
to a fine powder, and as it is very hard and tough its reduction to
powder by purely mechanical means is troublesome and expensive.
In treating the said "Val-de-Travers" rock according to my Invention
for the purpose of reducing it to powder I expose it in lumps to a

page_text: temperaturo of about 300 degrees Fahrenheit, by preference in the
machine or apparatus hercin-after described. The said rock contains
in addition to limestone and bitumen a small quantity of water. On
exposing the rock to the temperaturo indicated the water contained in
it is volatilized, and on its liberation a complete disintegration of the
rock takes place, the lumps becoming so soft and friable that by gentle
The temperature
pressure they may be reduced to fine powder.
required for producing this disintegration does not interfere with any
of the valuable properties of the rock.
My improvements in machinery or apparatus employed for reducing
the said rock to powder are as follows:-A hollow cylinder or drum is
mounted on a horizontal axis on which it is made to rotate slowly. This
drum is contained within another fixed hollow cylinder or casing, and
in the space between this and another outer casing the fire from a
furnace or furnaces situated below the said casings passes and effects
the heating of the rotating drum. The said furnaces are not imme-
diately underneath the axis of the drum, but are placed so as to leave
the space immediately underneath the axis of the drum clear.
cylindrical portion of the rotating drum is made wholly or in part of
bars or grating, and one end of the said drum has an opening at which
the rock to be treated can be fed into the drum by a shoot or hopper.
Immediately under the drum a pair of slowly rotating plain rolls are
situated, and beneath them a trough or channel having a rotating
archimedian screw.
The
The action of the machinery or apparatus is as follows:-The rock to
be operated upon is introduced into the rotating drum by the shoot or
hopper, the fire in the furnaces being lighted and the drum rolls and
screw being put in motion, the rock becomes gradually and uniformly
heated until it has reached the disintegrating temperature, when by
the lumps rolling over cach other in the drum the friable portions
become detached and fall through the grating on to the rolls beneath.
By passing between the said rolls the pulverizing of the rock is com-
pleted, and the powder is carried by the screw described to an endless
band, by which it is conveyed to the mastic boilers or powder heaters,
or is conducted into a receptacle.
My Invention is applicable to other mineral substances of like
character to "Val-de-Travers" rock.

page_text: Although I have found the temperature indicated sufficient yet I do
not limit myself to any particular temperature, neither do I limit myself
to the use of the machinery or apparatus described for completing
the pulverizing of the disintegrated rock.