IMPROVEMENTS IN THE MANUFACTURE OF GAS FOR THE PURPOSES OF ILLUMI- NATION
Year: 1839

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, wc, GEORGE
Lowe, Engineer to the Chartered Gas Company, and JOHN KIRKHAM, Engineer
to the Imperial Gas Company, both of London, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Fourth day of December, in the third year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto us, the said George
Lowe and John Kirkham, Her especial licence, full power, sole privilege and
authority, that we, the said George Lowe and John Kirkham, our exors,
adiiors, and assigns, or such others as we, the said George Lowe and John
Kirkham, our exors, adññiors, or assigns, should at any time agree with, and
no others, from time to time and at all times during the term of years therein
expressed, should and lawfully might make, use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed, our Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF GAS FOR THE PURPOSES OF ILLUMI-
NATION;" in which said Letters Patent is contained a proviso that we, the said
George Lowe and John Kirkham, or one of us, shall cause a particular
description of the nature of our said Invention, and in what manner
the same is to be performed, to be inrolled in Her said Majesty's High
Court of Chancery within six calendar months next and immediately after
the date of the said in part recited Letters Patent, as in and by the same;
reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, we, the said
George Lowe and John Kirkham, do hereby declare that the nature of our

page_text: said Invention, and the manner in which the same is to be performed, are
fully described and ascertained in and by the following statement thereof,
reference being had to the Drawings hereunto annexed, and to the letters
and figures marked thereon, that is to say:
Our Invention relates, first, to a mode of combining and working retorts in
the manufacture of gas from coal, and in such manner that the products
alternately of one of two retorts shall be caused to pass into and mix with
the products of the other retorts, by which means, whichever of the two retorts
has been last charged, the products thereof during the early hours of working
shall pass into the retort which with its charge is in a highly heated state,
from its having been much longer at work; and the retorts are so connected,
that by means of a valve and apparatus external of the brickwork of the
setting of the retorts, that during the time of discharging and charging either
of the retorts, the gas from the other retort shall not pass into the retort with
which it is connected, and which is being discharged of its contents or
charged with coal. It should be remarked in respect to this part of our
Invention, that Letters Patent were granted to the said George Lowe on the
Twelfth day of October, One thousand eight hundred and thirty-one, and
amongst other things the Specification enrolled to the said Patent described
a mode of generating gas in a single retort which was charged alternately
at the two ends, whereby the gas evolved at one end from a fresh charge of
coal during the whole hours of working was caused to mix with the gas
evolved from coal which had been some considerable time undergoing the
process of distillation, and by such combining of gas of the two charges in
the same retort, and causing the gas produced from the fresh charge to be
acted upon by coal which was highly heated, he was enabled to obtain very
considerable advantages over the ordinary means of constructing and working
retorts, at the same time the mode so described by the said George Lowe in
his said former Specification was liable to objection from the length of retort
which it was desirable to have, in order most advantageously to work out the
principle then first applied, and the said mode was further liable to objection
in consequence of the gas evolved at one end of the retort escaping during
the time of discharging and recharging the other end of the retort. The first
part of the present Invention consists of improvements in applying the above-
mentioned principle of operation or working retorts in the manufacture of
gas from coal,
DESCRIPTION OF THE DRAWINGS.

page_text: Figure 3, a plan in section. In each of these Figures the same letters are
employed to indicate similar parts, A and B being two retorts, and it will be
seen that these two retorts A and B are connected together at the back ends
thereof by the pipe C having an ordinary slide valve at D, by which the
communication between the retorts A and B can be shut during the time of
charging or discharging either of those retorts. E, F, are slide valves on the
dip pipes of the retorts A and B, in order to cause the gas of the two retorts
A and B to pass away by one or other of the dip pipes; thus, supposing the
retort B to have been last charged the valve F would be closed, and all the
gas would be passed off through the valve E, and this state of things would
be changed as soon as the retort A was recharged. The mode of constructing
and setting gas retorts, excepting the mode of connecting the same, being
well understood and forming no part of the Invention, and as all the necessary
parts are clearly shewn in the Drawing, no further description thereof will be
required, and it will only be necessary further to add a description of the
apparatus of working with the retorts A and B, in order to make this part of
our Invention most fully understood:-We will suppose that the retorts A
and B are at work, and that one or other is charged every six hours or eight
hours, for it should be understood that we do not charge them both at the
same time, but at a distance of three or four hours apart, that is, about half
the time of working off a charge; thus, supposing that the retort B has been
at work three or four hours after having been charged, the retort A would
be ready to be drawn and recharged, the valve F being first opened, the
valve D closed, and the valve F will remain open during the remainder of the
working of the charge in the retort B. And when the retort A has been
again charged and closed, the valve D again opened, and the valve E closed,
the products of gas of the retort A would pass into the retort B, and mix
with the product of gas evolved in that retort, and at the same time the gas
evolved in the retort A will, by passing into the retort B, be acted on by the
highly heated state of the retort B and its charge, and by such means all the
advantages of the said George Lowe's former Invention will be obtained
when manufacturing gas according to this part of our Invention, without
being liable to the objections to which the mode described in the former
application was subject. It will be evident that when the charge in the retort
A has been at work about three or four hours the time will have arrived for
drawing and recharging the retort B, after which the products of gas obtained
in the retort B will pass into the retort A through the valve D, and away
through the valve E; thus it will be seen that each of the retorts A and B
alternately receives the products of the gas of the earlier hours of distillation

page_text: of the retort. It may be desirable to remark, that although we have described
the retorts A and B to be side by side, it is evident that they may be one
over the other, and we have not thought it necessary to describe the other
'pair of retorts, they being similarly combined and worked as the retorts
A and B.
Another part of our Invention relates to the combined using of clay retorts
and iron retorts. In setting iron retorts, as is sometimes practised when
working according to what is called the descending-flue plan, the upper
retorts of iron are usually shielded or protected with fire bricks or tiles when
the furnace is so arranged as to cause the progress of combustion to pass
downwards after having ascended and passed over the upper retort or retorts,
as is very commonly practised, and such shielding or protecting the upper
iron retorts is rendered necessary, owing to the great head to which
the upper retorts under such circumstances are subjected. In some cases
clay retorts have been used, but without combining therewith retorts of iron
in the same furnace or oven, by which arrangement, although beneficial in
respect to the upper retort or retorts, owing to the great heat to which they
are liable, such arrangement is not beneficial for the lower retorts, which being
operated upon by a much lower degree of heat the slow conducting properties
of clay retorts do not in such situations offer that quick means of transmitting
the heat to the interior of such retorts as is desirable.
Now the object of the second part of our Invention is, to employ upper
retorts made of clay and the lower retorts made of iron. Figure 4 shews a
section of six retorts, the two upper ones being of clay and the four lower
ones of iron. By this arrangement it will be seen, that at those parts of the
oven where the greatest heat will be found to exist the retorts are made of
clay, and at those parts where the temperature will be much less, and where
it will be desirable to conduct the caloric as quickly as possible into the
retorts, the better conductor, iron, is employed for such retorts. Although
six retorts, shewn working according to this part of our Invention, will be
found a convenient number, we do not confine ourselves thereto, as other
numbers will be employed, provided the mode herein described of combining
the use of clay retorts with iron retorts be retained.
Another part of our Invention relates to a mode of applying heat to retorts
during the early hours of decomposition. It is well known that during the
early periods of the working off of a charge much of the products evolved are
not converted into permanent gas, but are condensible vapours which arise from
the circumstance of the cooling down of the retorts by the fresh charge of coal;
hence it is desirable to have a more excited combustion of the fuel employed

page_text: during the early hours of distillation than has heretofore been practised; and
this part of our Invention consists in applying a blast of air into the ashpit of
the furnace, the ashpit being closed, as is well understood in constructing
furnaces with closed ashpits for other purposes; and in carrying out this part
of our Invention, when the retorts have been fresh charged, we cause a blast
of air to be forced into the closed ashpit, in order to excite the fire in the
furnace, that it may continually keep up the heat of the retorts notwithstand-
ing the quick rate at which the heat is taken up and carried off by the charges
of the retorts during the early part of the distillation, and we keep up such blast
of air for about two or three hours, and then open the ashpit, and permit the
fire to burn by its ordinary draught. In applying a blast to a furnace with
gas retorts we employ a bellows or other suitable blowing apparatus, as is
well understood when applying a blast of air to the ashpit of a furnace for
other purposes. We would remark that, although we have spoke of employ-
ing a blast for two or three hours, the time necessary will be found to vary;
but the workman will readily judge whether his retorts are getting too hot,
and will modify or wholly cut off the blast of air, and by means of a damper
will regulate the working by the ordinary draught.
Another part of our Invention relates to a mode of heating retorts in the
manufacture of gas, and it consists of an improved mode of employing gas
tar as fuel. In performing this part of our Invention we mix breeze or small
cinder with a quantity of coal tar to saturate it, which we charge into one of
the retorts, and by a pipe we conduct the distilled products from such retort
to the fire of the furnace which is heating that and other retorts in the same
ovens. By this means we are enabled beneficially to consume coal tar. This
part of our Invention will be found particularly advantageous when the num-
ber of retorts in an oven or ovens are too many for producing the quantity of
gas required at a given time, which is often the case, and in place of letting
the retorts lie idle in such cases, the products from them, when charged with
breeze and tar, would be turned into the fire by having pipes applied to the
mouth pieces or other convenient parts of the retorts; and when it is desired
again to use such retorts for manufacturing gas for the purposes of illumina-
tion, the cocks or valves which are placed on the additional pipes leading to
the fire are to be closed. We would remark, that we are aware that coal tar
has been before used as fuel in gasworks, and it has been mixed with cinder
for making it into lumps. Our Invention does not relate thereto; but this
part of our Invention is confined to the application of such material by dis-
tilling therefrom combustible products, which we convey into the furnace of
gas ovens, as described.

page_text: .
Another part of our Invention relates to a mode of constructing and work-
ing retorts, which are set vertically or nearly so, and so arranged as to be
charged at the upper ends, and from time to time drawn at the lower ends,
and wherein the fresh charges are constantly ascending towards the lower
ends; and the novelty of our Invention consists in so constructing such retorts
as to cause the gas evolved from the fresh charges to descend and pass amongst
the highly-heated charges, and mix with the gas evolved therefrom, whereby a
similar result will be obtained to that first described, the products of gas
evolved from the fresh charges not being permitted to pass off by themselves,
but are caused to mix with products of gas evolved from charges which have
been much longer under operation.
Figure 5 shows two retorts of iron or of clay which are set vertically in an
oven, the nature of which, and the mode of heating them by a furnace, is
clearly indicated and shewn by this Figure of the Drawing; and it will be
seen that the retorts are sheilded with fire brick where the heat from the
furnace is most intense. A, A, are the two ascending pipes which by their
dip pipes conducts the gas into the hydraulic main, as will readily be under-
stood on examining the Drawing; and it will be seen that the ascending pipes
A enter into their retorts very low down, consequently there will be a large
quantity of the highly-heated charge above, through, or amongst which the
products of gas evolved above from the fresh part of the charge must neces-
sarily pass, in order to pass away out of the retort, and in so passing down,
the
gas
I of the fresh part of the charge will mix with and pass away with the
products evolved from those parts of the charge which have been a consider-
able time under process. We prefer to form the retorts of a conical shape, as
shewn, and the lower end of each retort enters into a tank B, which is kept
full of water, the tank B being of such a length as readily to allow of the
coke or cinder to be raked from below the retort, and removed from the tank
at one end by shovels or other convenient instruments; and it is important
to this part of our Invention that the retorts should be set vertical or so nearly
so as to ensure the charge descending when the coke or cinder is from time
to time removed. By this arrangement the charge in descending will be
immersed in water, and cooled down, and the charge may be caused to descend
at any speed which it may be found desirable according as the charge is found
to work off. At the upper end of each of the retorts there is a mouthpiece
having two slide valves, such as are usually employed in gasworks, whereby
the retorts can be charged from time to time without material loss of gas.
We would, however, remark, that other means may be resorted to to feed or
charge the retorts; and it should be understood, that we do not claim the

page_text: employing of vertical retorts, or the mode of charging them; and we would
remark, that we are aware that it is not new to draw the coke of gas retorts
into and below water when working with horizontal retorts, a Patent having
been before taken for forcing the charge with horizontal retorts by means of
pistons or rams, and thereby forcing out some part of the previous charge
through a descending pipe into a tank of water. It should be stated, that
we consider this part of our Invention less useful than the first part of our
Invention, when what is called caking coal is used; and therefore in such
cases we recommend the first part of our Invention in preference.
Having thus described the nature of our Invention, we would have it
understood that what we claim is,―
First, the mode of combining and working two retorts, as above described.
Secondly, we claim the mode of combining the use of clay retorts and iron
retorts, as above described.
Thirdly, we claim the mode of applying heat by means of a blast of air
during the early part of the process of distillation, as above described.
Fourthly, we claim the mode of employing coal tar as a means of heating
retorts of gasworks, as above described. And,
Fifthly, we claim the mode of constructing vertical or nearly vertical
retorts, whereby the products of gas evolved from the fresh parts of the
charge descend through the previous charges, and mix with the gas evolved
thereby.
In witness whereof, I, the said George Lowe, have hereunto set my
hand and seal, this Fourth day of June, in the year of our Lord
One thousand eight hundred and forty.