Muffles for use in Enamelling Metallic Articles.
Year: 1896

page_text: Date of Application, 8th Sep., 1896
Complete Specification Left, 5th June 1897-Accepted, 10th July, 1897
Muffles for use in Enamelling Metallic Articles.
We, THOMAS PREECE and ALLEN PREECE, trading together in copartnership as
Thomas Preece and Son, of 35 Gatis Street, Wolverhampton in the County of Stafford,
Furnace Builders, do hereby declare the nature of this invention to be as follows:-
The object of this invention is, to effect economy in fuel, equalization of temperature
within the muffle, and durability of the portions of the brickwork which are exposed to
the greatest temperature.
According to this invention, the gas producer or furnace is arranged at the back end
of the muffle, and the gas passes from the furnace over a bridge into a flue which runs
underneath the muffle or closed chamber within which the articles to be heated are
placed. The gas passes out through openings in one side of such flue, and from thence
through flues which are carried from such openings up through the brickwork of one
side of the muffle, over the top of the muffle, and down the other side thereof into a
flue from which they pass to the chimney. An air flue passes right through the fire-
bridge from one end to the other, being open to the atmosphere at each end; and
from this flue is carried a longitudinal air flue which passes clear through the
brickwork of the muffle to the front end thereof where it is open to the atmosphere.
This last-mentioned flue is carried at a level which takes it immediately underneath
the flues through which the gas passes out from the flue which is underneath the
muffle, at the portions thereof which are adjacent to such flue. This longitudinal
air flue has openings in its upper side which communicate with the flues through
which the gases pass from the flue which is underneath the muffle. A further air flue
is carried from the air flue through the fire-bridge, aforesaid, right through the
brickwork of the muffle to the front end thereof, at which it is open to the atmosphere;
and this flue passes over the tops of the portions of the flues through which the gases
pass out from the flue which is underneath the muffle, at the parts thereof which are
adjacent to the last-mentioned flue. This longitudinal air flue communicates, through
vertical flues, with the longitudinal air flue first described, and air which is drawn in
through the flue passes, consequently, into the longitudinal air flue first described.
The air which passes into the air flues through the end openings thereof keeps the
fire-bridge and the portions of the brickwork which are adjacent to the hotter side of
the muffle from being overheated and melting, and tends also to equalize the
temperature of the muffle; and the air itself becomes heated, and mingling with the
gases which pass out from the flue which is underneath the muffle ensure a thorough
combustion.
Contember 1906

page_text: Improvements in combined Self-producing Gas Furnaces and
Muffles for use in Enamelling Metallic Articles.
We, THOMAS PREECE and ALLEN PREECE, trading together in copartnership as
Thomas Preece and Son, of 35 Gatis Street, Wolverhampton in the County of Stafford,
Furnace Builders, 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 :-
Te object of this invention is to effect economy in fuel, equalisation of temperature
within the muffle, and durability of the portions of the brickwork which are exposed to
the greatest temperature.
In order that the invention may be clearly understood, we will describe the same by
the aid of the accompanying drawings, which illustrate a combined self-producing
gas furnace and muffle with our invention applied thereto.
Figure 1 is a longitudinal section through the centre of the combined furnace and
muffle.
Figure 2 is sectional plan, taken on line x x of Figure 1. Figure 3 is a transverse
section through the producer or furnace, taken on line y y of Figure 1, looking towards
the muffle; and Figure 4 is a transverse section through the muffle taken on line c¹¹
of Figure 1, looking towards the front end of the muffle.
A is the gas producer or furnace, which is of the usual construction, and B is the
muffle. The gas passes from the producer A over a bridge a into a flue C which runs
underneath the whole length of the muffle or closed chamber D within which the
articles to be heated are placed. The gas passes from the flue C through openings b
in one side thereof, and from thence through flues c which are carried from the
openings b up through the brickwork of one side of the muffle into an arched flue d.
This flue d consists of a hollow space formed between the crown arch of the muffle and
an arch which is built thereover, and extends the whole length of the muffle. The
upper arch of this flue is struck from a different centre to the lower arch, as shewn, so
that the flue becomes shallower towards the opposite side, of the muffle to that in
which the flues c are formed, to avoid the too rapid escape of the heated gases which
pass over the muffle. The exit side of the flue d communicates with a flue e formed
by chequer brickwork in the walls F of the muffle; and the gases pass from such
flue e, through openings f, into a flue E from which they pass to the chimney. The
first opening b is some distance, as shewn, from the bridge a, and the openings b
increase in size, as they are more remote from the bridge, with a view to ensuring an
equalisation of heat throughout the length of the flue C.
An air flue g passes right
through the length of the wall which divides the furnace from the muffle, a portion of
the flue passing lengthways through the fire bridge a. The main purpose of this flue
is to keep the fire-bridge a cool, and the ends of the flue are open to the atmosphere, as
shewn, to allow of a currrent of air passing through the flue. The main horizontal portion
of the flue communicates through vertical portions g¹, with short lengths g2 which run
out to the side of the brickwork above the ground line. From the flue g is carried an
air flue h, which passes longitudinally through the brickwork of the muffle, as shewn.
This flue is carried up above the level of the ground near the front end of the muffle,
where it is open to the atmosphere. This flue runs partially underneath the
openings b through which the hot gases pass from the flue C to the flues c, and
also underneath the flues c. Vertical flues i are formed in the brickwork between the
flues c, aud communicate between the longitudinal flue h and the flue d. The current
of air which passes through the flue h tends to keep cool the brickwork in the bottoms
of the openings b, and the currents of air which pass up from the flue / through the

page_text: flues i tend to keep cool the brickwork around the flues c; and the heated air issuing
from the flues i mingles with the hot gases which issue from the flues c and causes an
intense combustion within the flue d. A small air flue / runs longitudinally through
the brickwork of the muffle from the front of the muffle, where it is open to the
atmosphere, and communicates with one of the flues g. This flue runs over
the openings b, and the current of air passing therethrough tends to keep cool the
brickwork immediately above the openings. A recess m, which is open to the
atmosphere, is formed in the wall which divides the furnace from the muffle, and an
air flue k is carried up from the flue g into this recess, through the brickwork on each
side of the opening G through which the gases pass from the furnace into the
flue C. The currents of air through these flues tend to keep the brickwork cool.
The air which passes through the flues h, land i tends to prevent the whole of the
brickwork along the hotter side of the muffle from becoming overheated, and tends
also to equalize the temperature of the muffle.
The brickwork of the muffle and producer is, of course, strengthened, as usual, with
ironwork. A portion of this only, however, is shewn in the drawings.
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 in
respect of a combined self-producing gas furnance and muffle for use in enamelling
metallic articles, is :-
1. The means by which the hottest parts of the brickwork are prevented from
unduly heating by currents of air, substantially as described.
2. The means by which the brickwork along the hotter side of the muffle is
prevented from overheating, and the equalization of the temperature of the muffle
promoted, by means of currents of air, substantially as described.
3. The means by which air is heated and brought into contact with hot gases
within a flue which passes over the top of the closed chamber within which the
articles are submitted to the heat of the muffle, and intense combustion thereby
caused, substantially as described.
4. The arrangement of air flues, substantially as described, and shewn by the
drawings herewith, for the purpose set forth.
Dated this 3rd day of June 1897.
STEPHEN WATKINS,
Wolverhampton, Agent for the Applicants.