A New or Improved Process of and Apparatus for Desiccating Granular and Slimy or Pasty Materials or the like.
Year: 1899

page_text: Date of Application, 25th Sept., 1899-Accepted, 20th Jan., 1900
COMPLETE SPECIFICATION.
A New or Improved Process of and Apparatus for Desiccating Granular
and Slimy or Pasty Materials or the like.
We, GASTON DEVAUX, of Bretueil, Manufacturer, and HENRI DIEDRICH, of 89,
Rue d'Hautville, Paris, Engineer, in the Republic of France, do hereby declare
the nature of this invention and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement:-
-
This invention relates to a process of and apparatus for desiccating granular and
slimy or pasty materials or the like reduced to small fragments, and is more
especially applicable to phosphates, superphosphates, earth, marl, ore, distillers,
dregs or grains and the like.
In this process and apparatus the hot gases coming from a furnace, are mixed
by draught or asperation with air which is dried by being passed around the.
furnace, and this mixture of air and gases is caused to traverse a column or desic-
cating chamber in which the materials to be desiccated are caused to pass in an
opposite direction to that of the gases.
The mixture of dried air and gases is of a comparatively low temperature, which.
is maintained approximately uniform during the process of desiccation, by a
double jacket device which encloses the column.
The object of this comparatively low temperature is to permit of desiccation of.
those materials which are injured by contact with hot gases.
!
The mixed air and gases after performing their desiccating function leave the:
apparatus completely saturated with the moisture which they have absorbed from
the material under treatment.
The circulation of the air and gases is effected by an exhaust ventilator or
draught arranged at the upper part of the column.
The materials to be desiccated traverse the desiccating chamber and drop upon
a series of cast metal plates, and arms mounted on a vertical rotating shaft, con-
stantly turn them up, somewhat after the manner of a ploughshare, so as to
expose all their surfaces to the desiccating action of the air and gases.
In the accompanying drawings one practical constructional form of this appara-
tus is represented by way of example.
Figure 1 is a longitudinal section.
Figure 2 is a horizontal section through the furnace, and
Figure 3 is a cross section through the furnace.
In these drawings f is a furnace; a a regulating port or opening for the admis-
sion of cold air; b, b, are two openings enabling this air to enter the flue of the::
gases coming from the furnace; c, c are openings for the admission of the hot
gases to the column or desiccating chamber; d, d are openings for discharging the .
saturated gases; e, represents the exhaust openings of the ventilator, and g is the
column or desiccating chamber.
the
An exhaust at the top of the tower, connected at e, draws the whole volume of.
air and gases.
This exhaust produces the draught required for
combustion at f. The ash-pit-doors are provided with a circular damper allowing

page_text: only such a quantity of air to pass, as is necessary for ensuring combustion The
cold air to be dried passes through the damper a, and along the masonry of the
furnace and its mountings, and is dried and heated and in this condition arrives
at b, where it meets the gases of combustion, and a second combustion is set up by
the unconsumed oxygen of the fresh air, and a mixture of a perfect homogeneity
results.
;
The resulting mixture of air and gas traverses the perforated grid n and sur-
rounds the column at p.
The double jacketing of the column or desiccating chamber maintains the tem
perature of the desiccating chamber g during the desiccating process at a sufficiently
high temperature, by yielding up heat which is absorbed by the material to be
desiccated, in exchange for the water or moisture given off by the material under
treatment.
The gases entering the column g by way of the orifices c circulate through the
materials under treatment, absorb their moisture and are discharged into the
cavity o which is separated from the chamber p, thence they are exhausted by
the exhaust or draught.
The materials are raised by a bucket-chain or other suitable device, and are
delivered to the funnel k, at the bottom of which they are received by a helix q,
which conveys them to the interior of the column. Here they drop onto the middle
of the top plates, around the shaft.m. Arms provided with ploughs are
mounted on a vertical rotating shaft m, force the materials forward and from
the centre of the plate until they reach its edge and drop through the opening. v
onto the plater directly underneath. There they are caused to travel in a reverse
direction by arms k mounted on the same shaft m, and fitted with ploughs
arranged inversely to those above indicated which cause the material to be moved
toward the centre of the plater and to drop through the openings u at the
centre of r on to another plate s, and so on until the last plate of the series is
reached. The materials under treatment are moved upon each plate through a
spiral-like path.
A hopper is provided at the bottom of the column into which the material drops,
from the last plate and another helix is fitted at t which forces the desiccated
materials out of the apparatus.
The materials are constantly stirred in their passage with the object of succes-
sively exposing all their surfaces to the gases.
A modification of my invention may be employed, in which no air-admission-
ports c, c are provided, and so arranged that the hot gases would only come in
contact with the outside of the column or desiccating chamber, such a modification
may be advantageously employed in the case of the treatment of materials liable
to injury by contact with gases of high temperature. The column may if desired
be replaced by one of bricks or other suitable material.
In cases where the material to be dried must not be brought into contact with
the combustion gases, these gases may be utilised for heating air pipes supplying
hot air to the desiccating apparatus.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
1. A process of desiccating granular and pasty materials in which air first dried
around a desiccating furnace is either mixed or not by exhaust or draught with
the hot gases of combustion from the furnace, which are circulated through a
column, or desiccating chamber in a direction opposite to that in which the
materials in treatment are caused to travel: the said material being constantly
turned and stirred for the purpose of successively presenting all its surfaces to the
desiccating gases substantially as set forth.
2. A desiccating apparatus consisting of a column or desiccating chamber in
which plates are arranged one above the other with spaces between them in which

page_text: sets of rotating arms mounted on a rotating vertical shaft carry ploughs, the said
arms and ploughs being so arranged that alternate sets of arms and ploughs move
the material from the centre to the periphery and from the periphery to the
centre of successive plates. The said plates being alternately perforated at their
periphery and their centres so that the material under treatment drops from plate
to plate whilst the mixture of hot air and gases of combustion ascends in the
column substantially as set forth.
Dated this 05th dar of Cantamhan 1000