IMPROVEMENTS IN CEMENTATION FURNACES
Year: 1884

page_text: I JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN CEMENTATION FURNACES" which has been communicated to me from abroad by
Auguste Berthomieu of Paris in the Republic of France to be as follows:-
This Invention consists in certain improvements in the construction and
arrangement of cementing furnaces whereby the case or box containing the articles
to be treated is heated on all sides in such a manner that contents of the said box
are effectually protected from direct contact with the fuel and products of combustion
and whereby the progress of the operation can be controlled and regulated with
facility and precision as hereinafter described.
A cementation furnace constructed according to this Invention is provided with
fire places at the lower part of the furnace communicating with flues or spaces
underneath the box and is also provided with fire places or grates arranged between
the sides of the box and the outer walls or brickwork of the furnace. The box is
preferably divided by a vertical partition in the middle which partition assists in
supporting a cover which closes the upper part of the box. All the fire places
communicate with a space between the cover of the box and the roof or cover of
the furnace the said space being connected with a chimney for the escape of the
products of combustion from the fires. In the roof of the furnace are doors for the
introduction of fuel for heating the upper part of the box suitable apertures for
admitting air to and stoking and inspecting the side fire places being also provided
in the side walls of the furnace. Two side fire places are preferably employed
arranged one above the other being formed by gratings surrounding the box and
supported upon fixed projecting parts of the brickwork. The upper side fire place
serves to retain the fuel at the upper part of the furnace and the lower side fire
place extending round the bottom of the box serves to heat the lower part of the
sides of the said box. By regulating the combustion in the several fire places at the
bottom and sides of the furnace the heat can be controlled with great precision and
at the same time the articles undergoing cementation aro preserved from contact
with the fuel and product of combustion of the fires. The ashes from the side
furnaces are preferably caused to slide down passages into the ashpits of the bottom
fire places.
.

page_text: I JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention for "IMPROVEMENTS
IN CEMENTATION FURNACES" which Invention has been communicated to me froin
abroad by Auguste Berthomieu of Paris in the Republic of France and in what
manner the same is to be performed to be particularly described and ascertained in
and by the following statement:-
This Invention consists in certain improvements in the construction and
arrangement of cementation furnaces whereby the case or box containing the
articles to be cemented is uniformly heated on all sides and in such a manner that
the contents of the said box are effectually protected from direct contact with the
fuel and products of combustion and whereby the progress of the operation is
enabled to be controlled and regulated with facility and precision.
These results are obtained by placing the articles that are to be cemented in a
close box or case which is heated at the bottom and sides and also if desired at the
top by means of a series of independent fire places or combustion chambers arranged
as hereinafter described.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed sheet of drawings the same letters of reference
indicating corresponding parts in all the figures.
Figures 1 and 2 of the accompanying drawings represent in elevations at right
angles to each other a cementation furnace constructed according to this Invention.
Figures 3 and 4 represent vertical sections of the furnace the sections being taken
in planes at right angles to each other.
The articles to be cemented are placed in the box or case F preferably divided
internally by a partition G which assists in supporting a cover H serving to close
the upper part of the box F and protect its contents from contact with the fuel or
products of combustion. The box F is contained in a furnace X provided with a
removable roof or cover J a chimney L and a number of fire places or combustion
chambers arranged as hereinafter described. The bottom of the said box or case is
heated by means of fireplaces B (figures 3 and 4) provided with suitable fire bars or
grates N and ashpits A. Four of such fireplaces are shewn in the drawing but the
number may be more or less. The said fireplaces communicate through flues C
with a space C¹ where the products of combustion come into contact with and heat
the bottom of the case F. The fireplaces B are supplied with fuel through doors
at B and with air through the ash pit A. and apertures M and the products of
combustion after circulating underneath and around the case F are discharged into
the chimney at L.
The sides of the box or case F are heated by an independent fireplace or
independent fireplaces provided with suitable fire bars or grates and preferably
entirely surrounding the said box or case. This fire place or these fireplaces is or
are provided with doors B' and with air supply apertures M¹ the gaseous products
of combustion being discharged into the chimney L and the ashes falling through
passages D into the ashpit A. Two superposed fireplaces are shewn at E and E¹ in
the drawings but more or less may be used. The case F is heated at the top by the
combustion of fuel placed thereon in a chamber I formed between the cover H and
the removeable roof or cover J, closing the upper part of the furnace. Doors K are
provided in the roof J for the introduction of fuel, the chamber I being also supplied
with air through openings M². The gaseous products of combustion from this

page_text: chamber pass away through the chimney L and the ashes fall into the ash pit A as
herein before described with reference to the fireplaces E and E'.
By means of these arrangements the temperature of the case F is enabled to be
controlled with precision by regulating the progress of combustion in the fireplaces.
For example in case it is desired to apply a more intense heat at the upper part of
the case than at the lower part the fire in the fireplace E may be dispensed with
altogether. A considerable saving of fuel is also effected by means of these
improvements and the value of the product is greatly enhanced owing to the
uniformity and regularity with which the cementation or conversion into steel is
effected. The steel obtained by means of the improved furnace is perfectly regular
and homogeneous in structure whether the conversion be carried to the centre of
the article or merely to a limited depth.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is:-
First-In cementation furnaces the combination with a closed box or case for
containing the articles to be cemented of means for heating the bottom and sides
or the bottom sides and top of the said case or box for the purpose of enabling
the temperature to be regulated with precision and at the same time preserving
the articles undergoing cementation from contact with the fuel and products
of combustion substantially as hereinbefore described and illustrated in the
accompanying drawings.
Second-In cementation furnaces the combination with a closed box or case
(for containing the articles to be cemented) of a fire place or fire places beneath the
said box or case and an independent fire place or several fire places at the sides of
the said box or case and with or without a fire place or combustion chamber above
the said box or case substantially as and for the purposes hereinbefore described.
Dated this 13th dow of November 1801