IMPROVEMENTS IN PORTABLE FURNACES, AND IN GRATE BARS FOR THE SAME AND OTHER FURNACES
Year: 1881

page_text: LETTERS PATENT to John Tenwick, of Spittlegate, Grantham, in the County
of Lincoln, Moulder, for an Invention of "IMPROVEMENTS IN PORTABLE
FURNACES, AND IN GRATE BARS FOR THE SAME AND OTHER FURNACES."
PROVISIONAL SPECIFICATION left by the said John Tenwick at the Office
of the Commissioners of Patents on the 3rd January 1881.
_JOHN TENWICK, of Spittlegate, Grantham, in the County of Lincoln, Moulder.
"IMPROVEMENTS IN PORTABLE FURNACES, AND IN GRATE BARS FOR THE SAME
AND OTHER FURNACES."
I construct the furnace, which is more particularly applied for brewing purposes,
of wrought or cast iron, and in preference of a square form; the three sides of the
furnace are lower than the front plate. In the front plate I make a door for
supplying fuel and for the removal of cinders. I line the interior of the furnaco
with fire brick or other suitable material to protect the outside casing from the
action of the fire. On the front plate I fix a bracket or joint to connect a lever or
other appliance to actuate my grate bars, which are made of the form hereinafter
mentioned, which causes them partly to revolve to prevent the accumulation of
slag or cinder, and to discharge the same in the ash-pit of the furnace. On the
back end and the two sides of furnace I make a dip flange to run into a bed of
sand on a ledge or shelf, suitably formed in the interior fixed portion of the
furnace, which excludes the cold air and prevents the hot air escaping. I likewise
make the furnace to form a truck or carriage to run on, or without a rail with
wheels, and on one or more of the wheels I fix a worm wheel, which gears into a
suitable worm to facilitate the moving of heavy weights.
I make the exterior of my furnace of suitable form to correspond with the
movable part.
On the floor I lay rails for the purpose of withdrawing the furnace
from one copper or boiler to another, and make it available for any other copper
or boiler without extinguishing the fire that may be in a fit state to receive it.
By adopting this process a great waste of time and fuel is prevented. In the
old process the brewer is compelled to rake the whole of the fire from the furnace

page_text: •
when the liquor has had sufficient boiling, leaving the heat of the red hot furnace
and grate bars to dry the glutinous matter on the interior of the coppers, which
causes a great deal of labour to clean the coppers, and a great waste of time and
fuel in relighting the fire.
A most important advantage is gained by the use of my Invention in being
able to get conveniently at any time to the interior of the furnace to make repairs.
I make my grate bars of ordinary cast iron or malleable cast iron, but I prefer
malleable cast, as it is much more durable, and resists the action of the fire better
than any other metal. My bar is of a ridge form, and has a round gudgeon or
bearing cast on each end for the bar to partly revolve when required in suitable
bearings cast on the bridge piece, and, the front dead plate.
On one end of the bar I cast a crank, or otherwise secure the same on the end
of the bar to connect with a lever or winch handle, or other suitable means to
actuate and move the bars either singly or collectively, as required, which will
open to allow the slag or cinder to drop into the ashpit; the slag will run to the
lowest portion when in a fused state, and when the bars are moved the fused slag
drops through the bottom.
My furnace is similar to a corrugated floor or roof, it therefor gives one third
more space for the admission of air than is possible to be obtained by a level
surface.
I use the diagonal slots for the admission of air, the same as I claim in my
Patents No. 3090 of the year 1875° and 1121 of the year 1878.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Tenwick in the Great Seal Patent Office on the 1st July
1881.
JOHN TENWICK, of Spittlegate, Grantham, in the County of Lincoln, Moulder.
"IMPROVEMENTS IN PORTABLE FURNACES, AND IN GRATE BARS FOR THE SAME
AND OTHER FURNACES."
I construct the furnace, which is more particularly applied for brewers" use, of
wrought or cast iron, and in preference of a square form; the three sides of the
furnace are lower than the front plate. In the front plate I make a door for
supplying fuel and for the removal of cinders. I line the interior of the furnace
with fire brick or other suitable material to protect the outside casing from the
action of the fire. On the front plate I fix a bracket or joint to connect a lever
or other appliance to actuate my grate bars, which are made of the form herein-
after mentioned, which causes them partly to revolve to prevent the accumulation
of slag or cinder, and to discharge the same into the ash pit of the furnace. On
the back end and the two sides of the furnace I make a dip flange to run in a bed
of sand on a ledge or shelf, suitably formed in the fixed portion of the furnace,
which excludes the cold air and prevents the hot air escaping.
I likewise make the furnace to form a truck or carriage to run on or without a
rail with wheels, and on one or more of the wheels I fix a worm wheel, which
gears into a suitable worm to facilitate its easy removal. I make the exterior of
my furnace of suitable form to correspond with the moveable part. On the floor
I lay rails for the purpose of withdrawing the furnace from one copper or boiler
to another, and make it available for any other copper or boiler which may be in
a fit state to receive it without extinguishing the fire.
By adopting this process a great waste of time and fuel is prevented. In the
old process the brewer is compelled to rake the whole of his fire from the furnace
when the liquor has had sufficient boiling, leaving the heat of the red hot furnace
and grate bars to dry the glutinuous matter on the interior of the coppers, which
causes a great deal of labour to clear the copper, and a great waste of time and
fuel in relighting the fire. A most important advantage is gained by the use of
my Invention in being able to get conveniently at any time to the interior of the
furnace to make repairs.
I make my grate bars of ordinary cast iron or malleable cast iron, but I prefer
malleable cast, as it is much more durable, and it resists the action of the fire better.
than any other metal. My bar is of a ridge form, and has a round gudgeon or
bearing cast on each end for the bar to partly revolve when required in suitable
bearings cast in the bridge piece and the front dead plate. I cast a crank or
otherwise secure the same on the end of the bar to connect with a lever or winch
handle or other suitable means to actuate and move the bars, either singly or
collectively as required, which will open to allow the slag or cinder to drop into
the ashpit; the bars may be actuated by mechanism if preferred, and a continuous
or an intermittent motion kept up. The slag will run to the lower position when
in a fused state, and when the bars are moved the fused slag will drop through the
bottom. My furnace is similar to a corrugated floor or roof, it therefore give one
third more space for the admission of air than is possible to be obtained by a level
surface. I use the diagonal slots for the admission of air, the same as I claim in
my Patents, No. 3090, of the year 1875, and 1121 of the year 1878.
My Invention will be clearly understood by the annexed Sheet of Drawings, in
which, at Figure 1 a front elevation and Figure 2 a plan, I show my improved

page_text: construction of portable or removeable furnace, which is capable of being shifted
from one boiler to another with the fire contained within its walls. A, A, A, are
the upper side walls of metal, and at an incline against and upon which ordinary
fire brick or cement is applied to prevent injury to the metal, and to maintain the
temperature. The lower flanges of the two sides B, B, have dip pieces or wings
C, C, to run in a trough of sand when pushed into position under a boiler in a
similar manner to that described in my previous Patent. The front wall D of my
portable furnace is of greater height than the side or back walls, and this fits
against the front of the brick setting of the boiler, and prevents escape of smoke
and heat. The front wall in Figures 1 and 2 has rails E, E, and a sliding door F
fitted, but the segmental door and frame shown at Figures 3 and may be arranged
to it if desired. This segmental door and its frame are somewhat different to that
described in my previous Patent, because instead of working the door up or down
by rack and pinion, I now balance the door by a chain G and a weight H at each
side, and I guide the door by segmental groovings, into which the side edges of the
door engage;
I provide the door with a rock shaft I and two pauls J, J, which can
be lifted out of the teeth of the racks K, K, by the hand pull L when the door has
to be raised or lowered.
This arrangement of door permits an opening to be made above to allow of fresh
air entering at that part to commingle with the gases given off from the heated
fuel and also to damp the fire at any time as well as to enable the attendant to
observe the condition of the fire, the amount of opening at the upper part being
under his control. The door can also be lifted sufficiently to expose an opening
under its lower edge for feeding and raking purposes.
In a furnace so fitted I prefer to employ my improved double angled and slotted
bars W, W, of the form shown at Figures 2, 5, and 6, with a mid feather a, and so
arranged on end pins M, M, or some of them only, that a rock or canting motion
may be given them to free them from clinkers or slag as occasion demands. The
outer pivot ends of the bars having short links N, N, connected as in Figure 1,
that they or any number of them may be rocked at one time either by a key or
Where my double angled and
by a rod common to all or any number of them.
slotted furnace bars W, W, are arranged one set behind the other I form recesses of
square or other shape, and I fit separate pieces of metal into these recesses, as seen
at Figure 7, a portion being rounded as at P to rest upon the back transverse bar
of the furnace in order that the fire bars may be supported and yet be free to be
rocked thereon.
These double angled and slotted furnace bars W, W, form an important feature
in my present Invention whether they be of ordinary cast iron or of malleable cast,
because the spaces of the slots enable the air entering from the ash pit to become
more diffused and to pass through in thinner streams also at a higher temperature,
and consequently the better suited for admixture with the products of combustion
and commingling with the gases to ensure the development of intense heat, whereby
little else than spent vapour can escape from the uptake or chimney.
.
The portable furnace, Figures 1 and 2, with my double angled and slotted bars
fitted, is provided with flanged wheels Q, Q, to run upon rails, and in order to allow
of its easy removal from one furnace space to another I mount on one of the axles
Ra worm wheel S which can be geared into by the worm T which I fit on the
shaft U whose outer end is carried by the bracket V and is square for a key to be
fitted on, and by which the shaft can be rotated. The back end of the shaft is
fitted in a slot of the back bracket and a wedge shaped piece which can be removed
allows the worm to be lifted and wedged out of gear, such as when the furnace is
comparatively light or when sufficient labour can be had to move it, otherwise one
man with the worm in gear can operate it with a key.
As before stated, my double angled and slotted furnace bars are capable of being
fitted in any kind of furnace setting such as is ordinarily provided for fixed or
stationary engine boilers, for boilers of portable and other engines, for warehouse

page_text: and factory boilers, also for brewers, dyers, and other fire places for heating pans
and coppers or other vessels.
Having now described the nature of my said Invention and in what manner the
same is to be performed, I declare that I claim,―
First. The construction and arrangement of removeable furnace herein described,
and substantially as shown at Figures 1 and 2 of the annexed Drawings, and its
employment in the manner and for the purposes set forth.
Secondly. I claim the double angled or double inclined winged and slotted
furnace bars shown at Figures 1, 2, 3, and 4, in general views, and at Figures 5 and
6 in detail on the annexed Sheet of Drawings.
In witness whereof, I, the said John Tenwick, have hereunto set my hand
and seal, this Twenty eighth day of June, in the year of our Lord One
thousand eight hundred and eighty one.
JOHN TENWICK. (L.S.)