Year: 1888

page_text: I, CHARLES JAMES DOBBS of Middlesborough in the County of York do hereby
declare the nature of this invention to be as follows:-
In the Specification to my Patent No. 3870 of 1883 I described the use of kilns for
annealing paving blocks made of furnace slag, in which the blocks were annealed
exclusively by their own heat. Although the manufacture can be perfectly carried out
by this process, I have found that it is sometimes advantageous to provide a certain
amount of extraneous heating to the floor of the kiln in order to prevent any chilling
of the lowest layer of slag blocks that are in contact therewith, and according to my
present invention I effect such heating by providing below the floor of the kiln, which
is made loose for this purpose, a pit or recess which is filled with a layer of any
suitable fuel, by preference coal, which layer after its introduction is enclosed
against the entrance of air, or practically so, by laying upon it a floor of bricks
the joints of which are grouted in. Upon then introducing a charge of slag
blocks, the heat conducted therefrom downwards through the floor sets up a very
slow combustion in the layer of fuel beneath, thereby producing sufficient heat to
prevent any chilling of the bottom slag blocks, and this combustion in taking place
very slowly, will continue a very long time so that it will only be necessary to renew
the layer of fuel after a number of charges of blocks have been acted upon in the
kiln.
The floor, being loose at the sides, will gradually sink down as the fuel is consumed,
and thus keeps this always enclosed and protected against the entrance of any air
beyond such exceedingly small quantity as may be required to keep up the heat.
n: 01 dore of Fabuary 1898
ABEL & IMRAY,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Annealing Kilns for Slag Blocks.
1, CHARLES JAMES DOBBS of Middlesborough in the County of York do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
In the Specifications to my Patent No. 3870 of 1883 I described the use of kilns
for annealing paving blocks made of furnace slag in which the blocks were annealed
exclusively by their own heat. Although the manufacture can be perfectly carried
out by this process I have found that it is sometimes advantageous to provide a certain
amount of extraneous heating to the floor of the kiln in order to prevent any chilling
of the lowest layer of slag blocks that are in contact therewith, and according to my
present invention I effect such heating by providing below the floor of the kiln which
is made loose for this purpose, a pit or recess which is filled with a layer of any suitable
fuel, by preference coal, which layer after its introduction is enclosed against the
entrance of air, or practically so, by laying upon it a floor of bricks the joints of which
are grouted in.
Upon then introducing a charge of slag blocks, the heat conducted therefrom
downwards through the floor sets up a very slow combustion in the layer of fuel
beneath, thereby producing sufficient heat to prevent any chilling of the bottom slag
blocks and this combustion in taking place very slowly will continue a very long time
so that it will only be necessary to renew the layer of fuel after a number of charges
of blocks have been acted upon in the kiln.
The floor being loose at the sides will gradually sink down as the fuel is consumed
and thus keeps this always enclosed and protected against the entrance of any air
beyond such exceedingly small quantity as may be required to keep up the heat.
Fig. 1 of the accompanying drawing shews a part front elevation and part longi-
tudinal section of a set of kilns constructed according to my above described invention
and Fig. 2 shews a cross section through one of the kilns.
The general construction of the kilns is the same as described in the Specification to
my above mentioned prior Patent No. 3870 of 1883 the only difference being that the
floor A is loose from the sides B B and has below it a pit or recess C which is filled
with coal or other suitable fuel, the floor A which is formed of loose bricks or slabs
being removed for the introduction of the fuel and then replaced and grouted in so as
to exclude the air as much as possible. The kiln being then charged with the highly
heated slag blocks, the heat from these will be conducted down through the floor A
so as to set light to the layer of fuel in C, which owing to the exceedingly small
quantity of air penetrating through the floor will burn away at a very slow rate, the
loose floor A sinking down as it becomes consumed.
As before stated the slow rate at which the combustion takes place will enable the
layer of fuel to last a long time, so that a number of charges of slag blocks can be
treated in the kiln before the layer will require renewing.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what
I claim is :-
Constructing annealing kilns for slag blocks with an enclosed pit or recess for the
reception of a layer of fuel below a loose floor which fuel becoming ignited by the
heat of the slag blocks burns away slowly the floor being made to sink down as
the fuel is consumed, substantially as and for the purposes herein described.
ABEL & IMRAY,
Agents for the Applicant.