AN IMPROVEMENT IN CARBURETTING GAB, ALSO IN THE PREPARATION OF HYDROCARBONS FOR CAR- BURETTING GAS. AND IMPROVED METHODS OF TREATING ALKALI WHICH HAS .BEEN USED TO PURIFY. COAL OILS, SHALE OILS, PETROLEUM, AND OTHER MINERAL Оття
Year: 1865

page_text: LETTERS PATENT to William Renwick Bowditch, of Wakefield, in the
County of, York, Clerk, for the Invention of "AN IMPROVEMENT IN
CARBURETTING GAB, ALSO IN THE PREPARATION OF HYDROCARBONS FOR CAR-
BURETTING GAS. AND IMPROVED METHODS OF TREATING ALKALI WHICH HAS
.BEEN USED TO PURIFY. COAL OILS, SHALE OILS, PETROLEUM, AND OTHER MINERAL
Оття."
PROVISIONAL. SPECIFICATION left by the said William, Renwick Bowditch
at the Office of the Commissioners of Patents, with his Petition, on, the
3rd, March 1865..
I, WILLIAM RENWICK BOWDITCH, of Wakefield; in the County of York;
Clerk, do hereby declare the nature of the said Invention for "AN: IMPROVE-
MENT IN CARBURETTING GAS, ALSO IN THE PREPARATION OF HYDROCARBONS FOR
CARBURETTING. GAS, AND IMPROVED METHODS OF TREATING ALKALI WHICH HAS BEEN.
USED TO PURIFY COAL OILS, SHALE OILS, PETROLEUM, AND OTHER MINERAL OILS," to
be as follows:-
My improvement in carburetting gas consists in heating hydrocarbons to
not more than 212 degrees Fahrenheit, and passing gas over the heated
hydrocarbons on its way from the meter to the burners. The vessel containing
the hydrocarbons is made to form part of gaseliers or other gas apparatus;
Price Bd.1

page_text: or it may be placed near the meter. Placing it near the burners is by
much the better plan. I find that the gas passing over the heated hydro-
carbons removes more of their vapour than it can retain, as vapour when
cooled by contact with gas pipes and fittings, and therefore that it is necessary
to place the pipes so that the condensed hydrocarbons can run back into the
vessel where they were originally vaporized, or into some gas-tight receptacle
placed for their reception.
By heating the hydrocarbons employed to napthalize gas I am able to use
those of higher boiling point than I could use without heating them, and also
to carburet gas more highly.
In my Specification of the Thirty-first day of October One thousand eight
hundred and sixty-two, I pointed out heavy naphtha and dead oil amongst
other substances as excellently adapted for carburetting gas when used in
my apparatus therein described. Experience shows that these substances,
especially dead oil, contain some portions which are too volatile, and other
portions which are not volatile enough to be used in an apparatus suitable for
burning the bulk, and that it will be a great improvement, to remove the more
volatile portions which are apt to cause smoke, and the less volatile which do
not vaporize with sufficient facility to yield a light at all comparable with that
obtained by using the bulk of the oils which are volatile in an intermediate
degree. To effect this improvement I place the oils in a still, and heat them
steadily to two hundred and seventy degrees Fahrenheit, and continue them
at this temperature so long as anything comes from the still. The receiver is
then changed, and the heat is gradually raised to four hundred and eighty
degrees Fahrenheit, or five hundred degrees Fahrenheit, and the portion
which distils between these temperatures is the portion I employ for burning.
This process of raising the temperature should occupy sufficient time for the
distillation of the oil of intermediate volatility. The remainder of the oil in
the still is then driven over by a suitable increase of temperature, received into
another vessel, and put to such uses as it may be adapted for.
. Oils obtained by. distillation of coal shale and petroleum are treated in the
way I have above described. They are heated in a still to two hundred and
seventy degrees Fahrenheit to remove compounds which are volatile at that
temperature, and afterwards to four hundred and eighty degrees Fahrenheit
or five hundred degrees Fahrenheit, and the portion which distils between
these temperatures is the portion I employ for burning.
Another of my improvements consists in treatment of alkaline solutions
which have been employed in the purification of hydrocarbon oils. The
alkaline solution when removed from the oils contains oily acids and other

page_text: impurities. To remove these I pass a current of carbonic acid through the
alkaline solution until two layers are formed. One layer consists of oily acids
and similar substances; these are separated for use. The other layer consists
of caustic and carbonated alkali in water. This last-mentioned layer being
evaporated will furnish carbonate of the alkali, or being treated with lime
will furnish caustic alkali. The caustic solution may be again used in the
purification of hydrocarbon oils.
Another method by which I recover the alkali consists in exposing the
impure alkaline solution freely to the air for a considerable period.
The oily acids become decomposed and the alkali partially carbonated upon
being rendered caustic by the addition of lime in the usual manner, the alkali
is fit for use a second time in the purification of oils. Air blown through the
impure alkaline solution expedites the purification of the alkali.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Renwick Bowditch in the Great Seal Patent Office
on the 31st August 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
RENWICK BOWDITCH, of Wakefield, in the County of York, 'Clerk, 'send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, dated the Twenty-third day of March, One thousand eight hundred
and sixty-five, in the twenty-eighth year of Her reign, did, for Herself, Her
heirs and successors, give and grant unto me, the said William Renwick
Bowditch, Her special licence that I, the said William Renwick Bow-
ditch, my executors, administrators, and assigns, or such others as I, the
said William Fenwick Bowditch, 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 law-
fully 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 "AN IMPROVEMENT IN CARBURETTING GAS, ALSO IN THE PREPARATION
OF HYDROCARBONS FOR CARBURETTING GAS, AND IMPROVED METHODS OF TREATING
ALKALI WHICH HAS BEEN USED TO PURIFY COAL OILS, SHALE OILS, PETROLEUM, AND
OTHER MINERAL OILS," upon the condition, amongst others, that I, 'the said
William Renwick Bowditch, by an instrument in writing under my hand
and seal, should particularly describe and ascertain the nature of the said

page_text: 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 William Renwick Bowditch, do hereby
declare the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement (that is to say) :-
To carry out my improvement in carburetting gas I proceed as follows:-
I construct a gas-tight carburetting vessel (shown in the Drawings at K,
Figure 2) and at B, Figure 5,) of suitable material, (preferably of tinned iron
or copper.) To this vessel I make an inlet and one or more outlets for gas, as
shown in the Drawings, or in any other convenient manner. The outlets being
placed so that there is a free passage for gas when the vessel contains hydro-
carbons. I also make an aperture (shown in the Drawings at H, Figure 5, and
at S, Figure 3,) through which the carburetting vessel is supplied with hydro-
carbons. This aperture is closed by a screw plug or other suitable means, so
that it may be gas and vapour tight, except during the time when the hydro-
carbons are being supplied. Having placed some hydrocarbons in the
carburetting vessel and closed it securely, I turn on the gas to the burners
and heat the vessel and its contents by gas (a mode of doing which is shown
in the Drawings at J, Figure 2, and at K, Figure 5,) hot water or other
convenient source of heat so that the temperature of the contents is raised to
not more than two hundred and twelve degrees Fahrenheit. On its way from
the inlet of the carburetting vessel to the burner the gas passes over the
surface of the heated hydrocarbons, as shown, and carries with it a portion of
their vapour, by which its illuminating power is considerably increased. The
hydrocarbon vessel will require to be refilled from time to time as its contents
are consumed. It should be refilled whenever the light given by the car-
buretted gas is much less than ordinary, as the diminution of light proves that
the hydrocarbons are nearly exhausted. Condensation of the hydrocarbon
vapour takes place if the pipes through which it and gas pass be at ordinary
atmospheric temperatures. To prevent obstruction from this cause I incline
the pipes from the burners towards the hydrocarbon vessel, so that whatever
vapour is condensed by contact with the pipes must run back into the said
vessel. If the pipes be heated artificially to within twenty degrees or thirty
degrees Fahrenheit of the temperature of the hydrocarbons in the vessel,
condensation does not take place.
The vessel in which the hydrocarbons are heated is best made to form part
of gaseliers and other gas burning apparatus, as shown in the Drawings in
'

page_text: elevation, Figures 1 and 4, and in section Figures 2 and 5, and in plan
Figures 3 and 6. I always employ it thus when possible. When the
carburetting vessel cannot be incorporated in the gas burning apparatus, it
may be placed near the meter, or in any other convenient situation, but in
such case the gas pipes must be fitted so as to avoid any depressions to which
condensed hydrocarbons might lodge and accumulate in the pipe. By heating
the hydrocarbons employed to carburet gas I am able to use those of a higher
boiling point than I could use without heating them, and, owing to the com-
parative cheapness of the heavier hydrocarbons, I am able to produce light
more cheaply and with less heat than when it is obtained from gas alone, or
from gas and lighter hydrocarbons, such as benzole. The hydrocarbons which
I prefer to use on account of their cheapness and suitability are oils obtained
by the distillation of gas tar, and which boil between two hundred and fifty
degrees Fahrenheit and three hundred and fifty degrees Fahrenheit mixed
with naphthalin. The best mode of using them to dissolve the naphthalin
in the oils, and pour the mixture into the carburetting vessel, or first to fill
the carburetting vessel with naphthalin, and then to pour the oils upon it
until the vessel is sufficiently full. A vessel which appears to be full of
naphthalin will still contain a considerable quantity of oils, as the oils dissolve
the naphthalin when poured upon it, and cause it to occupy less space than it
occupies alone. Other hydrocarbons besides the above mentioned may be
used, but with less convenience and economy.
To carry out my improvement in the preparation of hydrocarbons for
carburetting gas I proceed as follows:-Experience shows that hydrocarbon
oils, especially dead oil, obtained from gas tar, contain some portions which
are too volatile, and other portions which are not volatile enough to be used
in an apparatus suitable for burning the bulk, and that it would be a great
improvement to remove the more volatile portions which are apt to cause
smoke, and the less volatile which do not vaporize with sufficient facility to
yield a light at all comparable with that obtained by using the bulk of the oils
which are volatile in an intermediate degree. To effect this improvement I
put the oils into a still, and heat them steadily up to two hundred and eighty
degrees or three hundred degrees Fahrenheit, and maintain them at this
temperature until not more than a few drops come from the still; I then
change the receiver and raise the heat very gradually to five hundred degrees
Fahrenheit, and the portion which distils between these temperatures is the
portion I employ for burning in the carburetting apparatus shown on the
Drawings annexed to my Specification of October Thirty-first, One thousand
eight hundred and sixty-two. This process of raising the temperature should

page_text: occupy sufficient time for the distillation of the oil of intermediate volatility.
I have found that with three hundred gallons of dead oil obtained from gas
tar, the heating to remove the water and lighter oils occupies about five
hours, and to remove the oils of intermediate volatility which I use for
burning the heating occupies about ten hours. The oil remaining in the still
and having a higher boiling point than five hundred degrees Fahrenheit, is
either distilled over into a separate receiver or drawn off from the still and
put to such uses as it may be adapted for. The above refers to dead oils
obtained by the distillation of gas tar, which I prefer to use whenever it can
be obtained. Oils obtained by the distillation of coal, shale, petroleum, and
other mineral oils are likewise treated in the way I have described above.
They are heated in a still to three hundred degrees Fahrenheit to remove
compounds which are volatile at that temperature, and afterward to five
hundred degrees Fahrenheit, and the portion which distils between these
temperatures is the portion which I employ for burning.
To carry out my improvements in the treatment of alkali which has been
used to purify coal oils, shale oils, petroleum, and other mineral oils, I proceed
as follows: I take the impure alkaline solution which is removed from the
oils and contains a quantity of oily acids and other impurities, and pass a
current of carbonic acid into it until two layers are formed. One layer consists
of oily acids and substances removed from the oils, and the other of caustic
and carbonated alkali in water. These layers are separated by a syphon or in
any other convenient manner. The oily compounds are employed for steeping
timber or other suitable use, and the alkaline solution is evaporated o obtain
its salts in the solid state, or it is treated at once with lime to obtain caustic
alkali. The caustic solution is fit for use in the purification of hydrocarbon
oils.
Another method by which I recover the alkali consists in exposing the
impure alkaline solution freely to the atmosphere for a considerable period.
By this treatment the oily compounds become decomposed, and the alkali
partially carbonated. Upon being rendered caustic by the addition of lime in
the usual manner the alkali is fit for use in the purification of hydrocarbon
oils, I have found the dark colored alkaline solution become of a light yellow
colour in about eight months. When this change of colour has taken place
it is fit to be rendered caustic for use. I also pass air or the gases of com-
bustion free from smoke through the alkaline solution, hot or cold, which
expedites the destruction of the compounds removed from the oil, and the
purification of the alkali.
I do not confine myself to the exact details pointed out, but I claim,-

page_text: Firstly, carburetting gas for illuminating purposes by passing it over heated
hydrocarbons, substantially as described.
Secondly, the preparation and use of hydrocarbons of an appropriate
volatility for carburetting illuminating gas, substantially as described.
Thirdly, the treatment of the alkaline residuum arising from the purification
of mineral oils so as to obtain useful substances therefrom, substantially as
described.
In witness whereof, I, the said William Renwick Bowditch, have here-
tofore set my hand and seal, this Twenty-ninth day of August, in the
year of our Lord One thousand eight hundred and sixty-five.
W. K. BOWDITCH. (L.S.)
Witness,
HENRY WM. BARBER,
J. CURTIS MICKLETHWAITE,
Clerks to Messrs. Scholey and Skipworth,
Solicitors,
Wakefield.
!