Improvements in Pottery Kilns,
Year: 1890

page_text: Date of Application, 26th Aug., 1890--Accepted, 13th Dec., 1890
COMPLETE SPECIFICATION.
Improvements in Pottery Kilns,
I, FRANK CALVIN ROBERTS, of South East Corner Fourth and Chestnut Streets,
Philadelphia, in the State of Pennsylvania, United States of America, Civil Engineer,
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 :-
The object of my invention is to adapt the regenerative system to convenient use
in a pottery kiln, and the accompanying drawings illustrate the invention in a
convenient form for application to the most usual type of kiln.
In said drawings
Figure 1 represents a horizontal section through the kiln and chimney, showing in
dotted lines the general arrangement of the flues.
Figure 2 is a central vertical section on the lines ww of Figure 1, and
Figure 3 is a similar section on the line of Figure 1.
The kiln proper is constructed with a circular wall A, having a dome shaped roos B,
and a floor C. At or near the centre of said floor is a down take flue E, above
which is a raised disc-shaped cover D, having a central opening V in its top and
radial openings U around the sides, so arranged as to cause a uniform out-flow from
all directions to the flue E.
The flue E descends for a considerable distance and communicates with a hori-
zontal flue F which extends outward and rises into a valve chamber G, containing
a pivot valve W. This may be the ordinary form of reversing valve used in
regenerative furnaces, and it controls the communication with two horizontal
flues H I which extend around the base of the kiln, preferably below the surface
of the ground as shown, and lead into a valve chamber K, in which is a second
pivot valve L controlling communication with the chimney J and with that part
of the chamber K which is open to the air. The flues H and I are preferably
formed with enlarged portions hi for a short distance on each side of the valve
chamber G, and this space may conveniently be filled with checker work such as
is commonly used in regenerative furnaces.
The flues H and I are alternately, of course, exit flues for the products of com-
bustion and entrance flues for air, and the control of these flues by means of the pivot
valves W and L is effected in the usual manner, the air being admitted at the
chamber K.
The chamber G communicates with the intake flue Q which leads to an annular
vertical intake flue R, from whose upper end a number of horizontal intake
flues S extend radially outward beneath the floor of the kiln, and communicate
by short horizontal inlet passages on each side with the vertical discharge jets T.
The main inlet passage for gas is shown at M (see dotted lines Figure 1) which
communicates with an annular flue N, surrounding the base of the kiln, and
communicating at intervals, by means of upwardly inclined intake passage O with
discharge jets P into the kiln proper. The jets P for the gas, and the jets T for
air, are arranged in groups of three, each gas jet being between two air jets, and
each group may be situated in a short vertical piece of brick work rising some
distance above the floor of the kiln so as to project the mingled air and gas
currents well up into the kiln before combustion takes place.
The operation of the system is as follows:
The gas (produced by means of any suitable generator) is admitted to the
passages M NO and flows into the kiln through the jets P.
The air is admitted at the valve chamber K and flows around through the flue H
until it is deflected by the pivot valve W into the passage Q thence it rises through

page_text: .
the annular flue R and flowing through the radial flues S is discharged at the jets I on
each side of the gas jets P.
The kiln is filled with the pottery, arranged in the usual manner and the firing
effected by the combustion of air and gas, which is diffused through the kiln by means
of the numerous outlets.
The products of combustion pass out through the openings V U descend by the
down-take flue E to the horizontal continuation thereof F and rise into the valve
chamber G where they are deflected by the valve W into the flue 1 by which
they pass to the valve chamber K where they are deflected by the valve L into the
chimney J and escape.
The courses of entering air and gas are indicated by the arrow a and the course of
the out-going products of combustion is indicated by the arrows 6 the direction of
which of course will be reversed with each reversal of the valves W and L.
If preferred, the gas to be burned may also be heated by means of a similar
regenerative system, such as for instance, a vertical or horizontal subdivision of the
annular flues H and I, one portion of which can thus be used to heat the air and
the other portion to heat the gas, while both subdivisions of the flues can be heated
by the out-going productions of combustion.
I am, of course, aware that the application of the regenerative system to a
pottery kiln is not broadly speaking new, and I do not claim such application
broadly.
I have found, however, that to make the principle available for use in a pottery
kiln it is essential that the flow of the currents within the kiln proper should always
be in the same direction. If, as is the case with ordinary regenerative systems, the
openings into the kiln are alternately used as exit flues for products of combustion
and entrance flues for air, it is not practicable to maintain a heat sufficiently uniform
to properly burn pottery, and an irregular and defective product will result. My
present invention overcomes this difficulty, and one of its most important features lies
in the fact that the reversal of direction of the currents takes place outside of the kiln
only, this mode of operation being permitted by the use, in connection with the per-
manent inlet and outlet passages, of a pair of exterior regenerator passages. So
far as I am aware, this principle has never been developed in any previous
application of the regenerative system to pottery manufacture, and I therefore desire
to claim its embodiment broadly, and irrespective of the particular arrangement of the
inlet and outlet passages, it being only necessary that they should be in such a
symmetrical relation to the kiln as shall produce a thorough and uniform distribution
of the heat.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a regenerative pottery kiln the combination with the kiln proper, of a
central downtake passage and flue leading therefrom, a pair of regenerator passages
communicating with said flue, a series of intake passages having jets arranged
circumferentially within said kiln and leading into the same, a flue connecting said
intake passages with the regenerator passages, a chimney, an air inlet, a pair of
reversing valves controlling the communication between the regenerator passages and
the said flues, air inlet and chimney, and a gas inlet having suitable passages leading
into said kiln, substantially as set forth.
2. In a regenerative pottery kiln, the combination of a kiln proper, a central
down-take passage having a cover and radial and vertical openings in said cover, a flue
leading from said down-take, a pair of semicircular regenerator passages communi-
cating with said flue, an air inlet and chimney, an intake flue communicating with
said regenerator passages, reversing valves controlling the communication between the
regenerator passages and the said chimney, said air inlet and said intake flue, an
annular passage leading from the intake flue and surrounding the downtake flue,
radial passages leading from said annular passage, inlet jets arranged in pairs around

page_text: the interior of said kiln and connected with said radial passages, a main inlet for gas,
an annular passage connected therewith and upwardly inclined intake passages leading
from said annular passages to the interior of the kiln and arranged between the pairs
of air inlet jets, substantially as set forth.
3. In a regenerative pottery kiln, the combination with the kiln proper, of a
permanent outlet passage for products of combustion, a pair of regenerator passages
communicating therewith, a plurality of permanent inlet passages for gas and air
having discharge orifices distributed in substantial symmetry within said kiln, flues
connecting the air inlet passages with the regenerator passages, a chimney, a main
gas inlet, and a pair of reversing valves controlling the communication between
said regenerator passages, said outlet passages, said air passages, said chimney and
said main air inlet, substantially as set forth.
Dated this 16th day of August 1890.
CARPMAEL & Co.,
Agents for the Applicant.