IMPROVEMENTS IN FURNACES FOR MELTING GLASS
Year: 1860

page_text: LETTERS PATENT to William Pilkington, of Windle Hall, within Windle,
in the County of Lancaster, Glass Manufacturer, for the Invention of
"IMPROVEMENTS IN FURNACES FOR MELTING GLASS."
Sealed the 2nd April 1861, and dated the 3rd December 1860.
PROVISIONAL SPECIFICATION left by the said William Pilkington at the
Office of the Commissioners of Patents, with his Petition, on the 3rd
December 1860.
I, WILLIAM PILKINGTON, of Windle Hall, within Windle, in the County of
Lancaster, Glass Manufacturer, do hereby declare that the nature of my said
Invention for "IMPROVEMENTS IN FURNACES FOR MELTING GLASS," to be as
follows:-
The manufacture of glass is at present effected by fluxing the materials
employed in earthenware pots in furnaces, into which the air necessary for the
combustion of the fuel is admitted through or between iron bars at the bottom
from openings underneath, commonly called caves, which extend thence into
the outer atmosphere.

page_text: This is the ordinary method. Now my Invention is the application of
steam in combination with air to the furnaces when in work, the steam being
projected against the bottom of the furnace, either through perforated iron
pipes or by other mechanical agents, or other known means or appliances, so
and in such manner as that the commingling of the steam and air shall be 5
effected while passing between the furnace bars into the furnaces.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Pilkington in the Great Seal Patent Office on the
30th May 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM 1
PILKINGTON, of Windle Hall, within Windle, in the County of Lancaster,
Glass Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of December, in the year of our
Lord One thousand eight hundred and sixty, in the twenty-fifth year of 1
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Pilkington, Her special licence that I, the said William
Pilkington, mý éxecutors, administrators, and assigns, or such others' a's I,
the said William Pilkington, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all times 2
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, än Invention for
"IMPROVEMENTS IN FURNACES FOR MELTING GLASS," upon the condition (amongst
others) that I; the said William Pilkington, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters 3
Patent.
NOW KNOW YE, that I, the said William Pilkington, do hereby declare
the nature of my said Invention, and in what manner the same is to be

page_text: performed, to be particularly described and ascertained in and by the fol-
lowing statement, that is to say
The furnaces ordinarily in use in the manufacture of glass are so constructed
and worked as that the air necessary to the combustion of the fuel, and the-
fluxing of the materials employed passes into the furnaces between the iron
grate bars at the bottom. from caves underneath communicating with the
atmosphere outside. My Invention consists in the improvement of these-
furnaces by the application of steam to the lower side of the grate bars. The
steam is generated in an ordinary boiler and conveyed thence in iron pipes into:
the caves of the furnaces, and then discharged through jets in- the pipes,
against the lower side of the grate bars; the pipes being placed sufficiently
near to cool the grate bars and the cinders in immediate contact above them,.
and at the same time to allow the steam to force forward and to some extent
mingle with the air before passing into the furnaces. This mode of combining
air with steam in working the furnaces greatly promotes the combustion and
calorific effects of the fuel, the aqueous vapour in passing through and over the
incandescent fuel suffers decomposition; its oxygen being absorbed by the-
highly heated carbon, carbonic oxide results, while the hydrogen passes off:
partly, uncombined and partly associated as carburetted hydrogen. These three-
products being capable of: undergoing further decomposition, yield a further
amount of heat, by being converted into carbonic acid and water. The calorie-
developed in this manner I find more than compensates for the fuel consumed '
in producing the gases. The use of steam, however, demands caution, for if
used in excess, it reduces rather than increases the heat, and it must freely
carry air along with it, the air required to promote the combustion of the
inflammable gases.
The advantages I derive from my Invention are these:-
1. A saving in grate bars and fuel is effected..
2. A steadier and greater amount of heat- from a less quantity of fuel is.
produced.
8. Small coal, called slack, which in the ordinary way of working a common.
furnace would pass through the grate bars, may be used,, and lastly the furnace
is worked with much less labor.
.
!
.
Having stated its nature and advantages, I will now proceed to describe the
mode I use to carry out my Invention.
In doing so, I will suppose a furnace of an ordinary construction having
the pots to hold the mow materiale in nosition and hair's in's Sit state

page_text: the charge of raw materials to be fluxed, I conduct the steam in an iron pipe
from the boiler in which it is generated to the under side of the grate, and
across the bottom in the line of the grate bars; at the distance of from twelve
to sixteen inches from them. The end of the pipe to the extent of the grate
is perforated with jet holes for the emission of the steam against the grate; I
find that jet holes of one-eigth of an inch in diameter, bored eight
inches apart, and in three lines, one to play perpendicularly, and the other two
at such an angle with it as that each line of jet holes will project the
steam in the direction of quarter distance from the sides of the grate to answer
very satisfactorily. I use ordinary gas piping of from one and a half inches
to. two inches in diameter. A stop valve must be placed in the steam pipe, in
some convenient position between the boiler and the grate, to regulate the
pressure of the discharges of steam or to cut it off as required. The position
of the boiler is not material, and will be determined according to convenience
and circumstances. So soon as the furnace fitted up with the steam pipe, as
before described is, in the ordinary process if glass making, charged with the
raw material, the steam valve is opened and the steam discharged at a
pressure of from eight to twelve pounds on the inch. It is not, however, to be
maintained at that pressure, but must be regulated according to the heat
required to carry on the process of glass melting; the pressure sometimes
being reduced as low as one or two pounds to the inch. I do not confine
myself to this particular mode of projecting the steam, other forms and combi-
nations of pipes may be used, due care being had not to discharge too great a
quantity of steam, and to secure a sufficiency of of air being carried forward
with the steam through the grate bars.

page_text: Invention the furnace or any of the appliances heretofore in use in the
manufacture of glass, but I do claim as my Invention the application of
steam in combination with air in working the ordinary glass furnace, as above
described.
In witness whereof I, the said William Pilkington, have hereunto set my
hand and seal, this Twenty-ninth day of May, in the year of our Lord
One thousand eight hundred and sixty-one.
Signed, sealed and delivered (being first
duly stamped) by the above named
William Pilkington, two lines, com-
mencing with "Figure 8," and
ending with "jet holes," having been
first struck out, in the presence of:
EDWP. JOHNSON, Sol".
W. PILKINGTON. (LB.)
St. Helens.
ROB. THOMAS, his Clerk.