IMPROVEMENTS IN CONNECTION WITH GAS RETORT STEAM BOILER AND OTHER FURNACES FOR GENERATING HEAT "
Year: 1883

page_text: LETTERS PATENT to John Dempster of the firm of Robert Dempster and
Sons, of Elland in the County of York, Gas Engineers for an Invention of
"IMPROVEMENTS IN CONNECTION WITH GAS RETORT STEAM BOILER AND
OTHER FURNACES FOR GENERATING HEAT
"
PROVISIONAL SPECIFICATION left by the said John Dempster at the Office
of the Commissioners of Patents on the 31st December 1883.
JOHN DEMPSTER of the firm of Robert Dempster and Sons, of Elland in the
County of York, Gas Engineers. " IMPROVEMENTS IN CONNECTION WITH GAS
RETORT, STEAM BOILER AND OTHER FURNACES FOR GENERATING HEAT'
"
The object of my Invention is to utilize the waste heat or gases arising from
retort benches or settings, and from steam boiler or other furnaces whereby a
saving in fuel is effected.
For the purpose of carrying out my Invention I construct and arrange at one or
both sides of the furnace, (according to varying circumstances) a series of zigzag
flues or openings, one end of each of such flues being in connection with the
furnace, whilst the other end of each of such flues are open to the atmosphere but
in connection with the usual flues employed for removing the heat and gases. The
quantity of air supplied to these flues being regulated and controlled by means of
dampers.
The bricks I employ for forming the newly arranged flues are of peculiar
construction, having steps formed therein so that when put together leave openings
or flues at right angles to each other. The spent gases pass through one of these
Blues whereby the bricks are heated, consequently the atmospheric air in passing
through the other flue also becomes heated, and when entering into the upper part
of the furnace, mingles with the carbonic oxide which is immediately ignited and
materially assists in heating the retorts. The heated air enters the furnace in thin
sheets by means of narrow tapering horizontal slits formed in the brick, whereby
a better mixture with the carbonic oxide is obtained and more perfect combustion
follows.

page_text: This special construction of furnace or generator may be used in connection with
ordinary grate bar furnaces, or those constructed on a V principle and can be
applied with equal advantage to existing retort settings or to boiler and other
furnaces at a much less cost than the present construction of furnace or regenerator,
and with less excavation and consequently with much less brickwork; also
avoiding water, rock or quicksand which is found in deep excavations.
In order to break the clinkers so that a supply of air may be freely admitted to
the fire when constructed on the V principle we employ a lever provided with
prongs operated by the workman without the necessity of his having to go down
onto a level with the furnace.
The pronged lever is placed underneath the fire with the prongs passing through
the slit entering into and amongst the fuel. At the rear of the lever is connected
one or more pulleys forming a carriage running upon rails, so that the workman
can run the wheels and lever backwards and forwards consequently sliding the
prongs to and fro in the slit and so breaking the clinkers in the furnace and
allowing for the admission of air.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Dempster in the Patent Office on the 30th June 1884.
JOHN DEMPSTER of the firm of Robert Dempster and Sons of Elland in the
County of York, Gas Engineers, "IMPROVEMENTS IN CONNECTION WITH GAS
RETORT, STEAM BOILER, AND OTHER FURNACES FOR GENERATING HEAT."
The object of my Invention is to utilize the waste heat or gases arising from
retort benches or settings, and from steam boiler and other furnaces, whereby a
saving in fuel is effected.
For the purpose of carrying out my Invention I construct and arrange at one
or both sides of the furnace, (according to varying circumstances) a series of zigzag
flues or openings, one end of each of such flues being in connection with the
furnace, whilst the other end of each of such flue is open to the atmosphere, but in
connection with the usual flues employed for removing the heat and gases. The
quantity of air supplied to these flues being regulated and controlled by means of
dampers.
The bricks we employ for forming the newly arranged flues are of peculiar
construction, having steps formed therein, so that when put together leave
openings or flues at right angles to each other. The spent gases pass through one
of these flues, whereby the bricks are heated, consequently the atmospheric air in
passing through the other flue also becomes heated, and when entering into the
upper part of the furnace mingles with the carbonic oxide which is immediately
ignited, and materially assists in heating the retorts, the said heated air entering
the furnace in thin sheets by means of narrow tapering horizontal slits formed in
the brick.
In putting my Invention into practice the gases are taken at the point where
they leave the "setting" and are conducted through a series of flues, situated
directly under the bottom Retorts, and which in large settings range from front to
back on each side of the furnace, but in small settings on one side of the furnace
only. These flues are formed of perforated bricks as shewn in the Drawings
Fig 1 and 2 so that when the bricks are put together, as seen in Fig. 2, a space A
is formed varying in size with the requirements of the setting. B is a flue or
opening made in the bricks. At Fig. 3 is another form of brick answering the same
purpose as Fig 2,
These bricks are kept apart by ordinary tiles which project at each side
alternately in order to direct the air in the desired direction, the bricks being
arranged in any number of tiers, or rows, in order to obtain more or less effect as
desirable, but by preference I use only 3 rows in adapting it to ordinary furnaces.
It will of course be understood that the spent furnace gases pass down the
vertical openings in the perforated bricks, and the incoming atmospheric air to be
heated traverses through the lateral openings formed by the recessed bricks as
before mentioned. The air passage commences at the lowest part of the Regenerator
and up through the bricks as described until it reaches the point of delivery into
the furnace where it enters a perforated brick having a tapered aperture as shewn
in Fig 4, the wider and bottom part of which communicates with the air channel
or passage, whilst the upper and smaller part leads into and forms part of the
furnace side, the tapered aperture by preference passes through the brick at an
angle of about 45 degrees, and is so arranged as to spread the air in a thin sheet
over the ascending carbonic oxide from the furnace, and thereby affording a ready
means of facilitating combustion, the openings for the admission of air into the
furnace being fitted with sliding lids or doors so that the quantity of air admitted

page_text: for the purpose of primary combustion may be thoroughly regulated as required.
The opening for the admittance of air into the recuperative part of the arrangement
for secondary combustion is also fitted with a slid ng lid or door in like manner.
I employ wrought iron grate bars preferably made with a semi circular groove
the whole of its length, on one or more sides, the object of which is to facilitate
the supply of steam to furnaces in such works as have no boiler, and in this
case the bats are fixed so as to fall towards the back of the Ashpan thus allowing
the water to run down and back into the incandescent fuel, the inclined grate bars
also allow of a greater body of coke to be in the furnace by means of its increased
depth. The admittance of water in the way described preserves the iron bars and
prevents their burning away. The principle object of the inclined grooved bars is
to introduce water to the hot coke or coal in the furnace whilst the steam generated
from this water is decomposed when passing through the burning fuel so that
Hydrogen Gas is produced which is carried in conjunction with the carbonic oxide
to the point where the secondary air supply is introduced, and there burns with an
intense heat. This system as berein described is specially designed for the purposes
of adoption in existing Retort Benches or Ovens, and by means of its small compass
can be introduced into any class of setting, to heat any number of Retorts as is
desirable or found convenient; it is also equally available for either single or double
benches with top or bottom main flues, steam boilers, Stills, Annealing Pans, and
other purposes where a very high temperature is required.
When the furnace gases have passed down and through the rows of perforated
bricks, they are conducted into the flue directly under the same and go on to the
back of the Regenerator where they turn to the right and left hand respectively,
into the bottom side flues, thence to the front and up an aperture into the top
side flues where they are taken back again into the main flue which in a double
bench is preferably in the middle, but in a single bench up flues arranged in the
back wall.
The grate bars are allowed to project some little distance beyond the furnace and
a pipe is laid close to same having small perforations, in number corresponding to
the bars and bored to come opposite same.
This pipe may be connected with the water main, or may be supplied from a
cistern or tank at a little elevation above the furnace bar, and in such a position as
to enable workmen to supply it with water at intervals, so as to render water supply
continuous when once regulated to requirements.
Having thus fully described the nature of my Invention, and the way in which
it may be constructed and used practically, I would have it understood that I
claim,
Firstly. The formation of bricks such as is herein shewn and described and for
purposes set forth.
Secondly. The formation of flues whereby the air can be brought in close
proximity to the furnace gases, and be heated thereby in manner substantially as
herein described.
Thirdly. The formation of bricks as shewn in Fig. 3. whereby the heated air can
be directed into the furnace in thin sheets substantially as described.
In witness whereof I the said John Dempster have hereunto set my hand
and seal this twenty seventh day of June, in the year of our Lord, One thousand
eight hundred and eighty four.