IMPROVEMENTS IN THE MANUFACTURE OF COAL GAS
Year: 1857

page_text: LETTERS PATENT to Alexander Angus Croll, of Harold's Wood Lodge,
near Romford, in the County of Essex, Civil Engineer, for the Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF COAL GAS,"
Sealed the 31st March 1857, and dated the 3rd January 1857.
PROVISIONAL SPECIFICATION left by the said Alexander Angus Croll at
the Office of the Commissioners of Patents, with his Petition, on the
3rd January 1857..
I, ALEXANDER ANGUS CROLL, of Harold's Wood Lodge, near Romford, in
the County of Essex, Civil Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF COAL GAS," to be as
follows:
Heretofore in the manufacture of coal gas it has been the practice to supply
the coal to the retorts for distillation in comparatively large quantities, so that
the charge in each retort is of considerable bulk, which I have found to be a
disadvantage; and my improvements consist in supplying the coal in such
manner that it may be distributed in thin layers in the retorts, so as to facilitate
rapidity of operation.
I prefer to have the coal reduced to small particles, and to keep up a
uniform supply by the application of self-feeding apparatus to the retorts in
place of the ordinary mode; and I effect the distribution of the coal in the
retorts by inclining the retorts or by means of distributors..

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander Angus Croll in the Great Seal Patent Office on
the 3rd July 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
ANGUS CROLL, of Harold's Wood Lodge, near Romford, in the County of
Essex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of January, in the year of our Lord One
thousand eight hundred and fifty-seven, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Alexander Angus Croll, Her special licence that I, the said Alexander
Angus Croll, my executors, administrators, and assigns, or such others as I,
the said Alexander Angus Croll, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
times 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, an Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF COAL GAS," upon the condition (amongst
others) that I, the said Alexander Angus Croll,my executors or administrators,
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 Patent.
NOW KNOW YE, that I, the said Alexander Angus Croll, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
Heretofore in the manufacture of coal gasit has been the practice to supply
the coal to the retorts for distillation in comparatively large quantities,so that
the charge in each retort is of considerable bulk, which I have found to be a
disadvantage; and my improvements consist in supplying the coal in such
manner that it may be distributed in thin layers in the retorts, so as to facili-
tate rapidity of operation. I prefer to have the coal reduced to small particles,
and to keep up a uniform supply by the application of self-feeding apparatus
'to the retorts in place of the ordinary mode; and I effect the distribution of
the coal in the retorts by inclining the retorts or by means of distributors.
But that the nature of my said Invention, and in what manner I carry the

page_text: Figure 1 shews a sectional side view of one arrangement of retort, and
Figure 2 a sectional side view of another arrangement for carrying out my
improvements. In each of the Figures the same letters refer to corresponding
parts wherever they occur. In each setting one retort only is shown, but it
will be readily understood that the improvements are equally applicable when
a series of retorts are used in the same setting.
b
a is the retort, which it will be seen in the one case is continuously inclined
in one direction, whilst in the other it inclines alternately in one and then in
the other direction. The angle or angles of inclination, however, may be
varied, as may also the length of the retorts from that shown. The coal is fed
to the retort a in small quantities continuously from the hopper b, which for
this purpose is provided with a screw shaft c, which is set in motion by a
strap or band from a steam engine or other power acting upon a drum or
pulley d upon the axis d', which is supported in suitable bearings, as shewn,
and has affixed upon it the bevilled pinion d2, which takes into the teeth of the
bevilled pinion c¹, affixed upon the screw shaft c, to give motion thereto, in
such manner that the coal supplied to the hopper & may be continuously
delivered in small quantities to the retort a. The lower part of the hopperb,
where it is connected to the retort a, is surrounded by a water-tight jacket e,
into which a supply of cold water is caused to flow by the pipe f, to pass away
as heated by the pipe g. The object of thus surrounding this part of the
hopper with a constant stream of cold water is to preventas much as possible
the heat of the retort being communicated to the coal in the hopper b, and
prevent its being charred before it enters the retort. The coal used I prefer
to be previously reduced to small particles, but the size of these particles will
depend upon the quality of the coal employed, or the angle given to the retort,
or the length of such angles, or other means of distributing such coal in the
retorts; the object in each case being to obtain all the gas from the coals-
before they reach the bottom of the retort. And in passing down the surface
or surfaces a¹ of the retort in a thin layer or stream, the heat given off from
the fire-place causes the gas to be speedily generated, which then passes off
in the ordinary manner by a pipe i to the hydraulic or other main, as is well
understood.
The retort a is provided with a mouth-piece and cover a², by which access
is obtained to the interior for clearing the same when required, and for

page_text: removing the coke therefrom as collected. The flame and heated particles
from the fire-place h are capable of acting all round the retort a, and thence
pass away by the flue ; to the chimney or stack, as is well understood.
Having thus described the nature of my said Invention, and in what manner
I carry the same into effect, I would have it understood that I do not confine
myself to the precise details shewn and described, as these may be varied; but
what I do claim is, the adaptation or combination of means whereby the
manufacture of coal gas is facilitated, in manner substantially as explained.
In witness whereof, I, the said Alexander Angus Croll, have hereunto
set my hand and seal, this Third day of July, in the year of our Lord
One thousand eight hundred and fifty-seven.
Witness,
W. BROOKES, Patent Agent,.
73, Chancery Lane.
A. ANGUS CROLL. (L.S.)