IMPROVED APPARATUS FOR CARBURETTING AIR AND GAS
Year: 1866

page_text: LETTERS PATENT to Edward John Cowling Welch, of Harrow, in tho
County of Middlesex, Engineer, for the Invention of "IMPROVED
APPARATUS FOR CARBURETTING AIR AND GAS."
PROVISIONAL SPECIFICATION left by the said Edward John Cowling
Welch at the Office of the Commissioners of Patents, with his
Petition, on the 16th February 1866.
I, EDWARD JOHN COWLING WELCH, of Harrow, in the County of
Middlesex, Engineer, do hereby declare the nature of the said Invention
for "IMPROVED APPARATUS FOR CARBURETTING AIR AND GAS," to be as
follows:-
The object sought to be obtained in this apparatus is to give a very
large carburetting surface to either the gas or air within as small a space
as possible. By my improved arrangement the light will be always cqual
and the liquid used always the same, that is, the more volatile portion will
not be at first absorbed and the heavier left behind. The body of the
liquid is separated from that which is actually in the course of evaporation,
and the supply takes place in proportion as the evaporation proceeds. The
exterior form of the apparatus is cylindrical. The upper portion forms a
tank or reservoir for the liquid; in the bottom of this tank is a valve
opening upwards, but held down by a spring and forced open when

page_text: required by a rod acting on a lever by the cap or plug (which stops up the
filling hole) being screwed down, so that when the cap or plug is removed,
as when filling the reservoir, the valve is closed. From the under side of
the valve seat a cone or tube dips into a small tin box open at the top, and
which holds a sufficient quantity of the liquid to seal the end of the tube
and prevent air passing up. From this box the liquid flows into the trays.
The carburettor consists of a number of shallow trays, each holding a
small quantity of the liquid at the bottom, and if any more comes into it
the surplus passes on to the next tray below. These trays are all filled
with some porous material which has great capillary attraction, such, for
instance, as cotton thread, which is threaded up and down through per-
forated tins placed about two inches apart. In the centre of the trays
there is an inner chamber, which is made of tin or other metal perforated
to within about half an inch of the top. The outer rim or sides of the
tray has holes perforated all round it. In some of the trays the air or gas
passes from the outside towards the centre, but in others it passes from the
centre to the outside. The air or gas will pass from the outside to the
inside of the first tray, then up through the small tube of the next tray
outwards and back so as to pass over a large surface of thread damped by
the liquid. The short pipes in the trays stand about half an inch above
the bottom of each tray in the centre, so that the liquid being the same
height in the centre chamber as in the other part of the tray as soon as
the liquid in the tray gets to its proper depth it overflows down this tube
to the next tray. The bottom tray of all has not the pipe, as if it got too
full the overplus would flow over the side perforations into the chamber
below, which will be presently described. Down the centre of all a pipe
passes from the top of the tank to near the bottom of the lower tray. This
pipe is termed the air pipe, and when the lower tray gets short of liquid
it admits air to the top of the tank and allows liquid to slowly descend
until the deficiency is supplied, when the bottom end of the tube is sealed
by the liquid in the lower tank; but before this is done all the upper trays
must each in their turn get 'full to the top of the little overflow pipes
before any can reach the bottom, and as the bottom is the one in which
there is by far the greatest evaporation (being the one through which the
air or gas first passes) there is always a slow flow of the liquid to it, which
on its way keeps all the trays supplied. Between the bottom of the tank
and top of the top tray there is a space which receives the air from the
centre of the upper tray, whence it goes into the outlet pipe, which opens
immediately below the bottom of the tank. The trays all have tops or

page_text: covers which fit inside the rim, and are cut out in the centre to the size of
the inner chamber, so that the tops fit in and allow the rim both of the
outside and inner chamber to pass above them. The top tray of all has
its top or lid the size of the case so as to fit it closely all round; this lid
or top fits on to the outer rim of the tray. Below the lower tray a space is
left to catch any liquid which may flow down beyond the proper supply.
This overflow may be caused by the filling plug not being screwed down
soundly, or by the apparatus being tilted. This lower chamber has a small
draw-off plug on a level with the bottom, so that any accumulated surplus
fluid may be drawn off so as not to impede the passage of gas or air. The
inlet enters this chamber immediately below the lower tray, so as to allow
about an inch between it and the bottom of the chamber for the overflow
to lie so as to leave the inlet clear of any liquid accumulated in the bottom.
When the apparatus is used for air the cold produced by evaporation is so
great that the body of the apparatus must be surrounded with a jacket of
warm water, the temperature of which may be kept up by a small burner jet
or by other suitable means. This warm water is not for producing the
evaporation of the liquid, but simply to keep the apparatus at the tempera-
ture of the air.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward John Cowling Welch in the Great Seal
Patent Office on the 15th August 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
JOHN COWLING WELCH, of Harrow, in the County of Middlesex, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of February, in the year of
our Lord One thousand eight hundred and sixty-six, in the twenty-ninth
year of Her reign did, for Herself, Her heirs and, successors, give and
grant unto me, the said Edward John Cowling Welch, Her special licence
that I, the said Edward John Cowling Welch, my executors, adminis-
trators, and assigns, or such others as I, the said Edward John Cowling
Welch, 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 "IMPROVED

page_text: APPARATUS FOR CARBURETTING AIR AND GAS," upon the condition (amongst
others) that I, the said Edward John Cowling Welch, 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 monthis next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Edward John Cowling Welch, 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, reference being had to the Drawing
hereunto annexed, and to the letters and figures marked thereon (that is
to say):
The object sought to be obtained by this apparatus is to obtain a very
large carburetting surface within as small a space as possible. By my
improved arrangement the gas or air will be well carburetted, and the light
will be always equal, and the liquid used will always remain of the same
quality, that is, the more volatile portion will not be at first absorbed and
the heavier left behind. The body of the carburetting liquid is separated
from that which is actually in the course of evaporation, and the
supply to the carburetting chamber takes place in proportion as tho
evaporation proceeds.
The Figure in the accompanying Drawing represents a vertical section
of my improved apparatus. The exterior form of the apparatus is cylin-
drical, and the upper portion forms a tank or reservoir A for the
carburetting liquid. In the bottom of this tank is a valve b attached to a
lever b', and opening upwards. This lever and valve is held down by a
spring c, and is forced open when required by a rod d, which is acted upon
by the cap or plug e, which stops up the filling hole above, so that when
this cap is screwed down, after filling the reservoir, the valve will bo
opened, but when the cap or plug is removed for the purpose of filling the
reservoir the valve will be closed by the spring c. From the under sido
of the valve seat a cone or tube f is made to dip into a small tin box g,
open at top, and which holds a sufficient quantity of the liquid to seal the
end of the tube f, and prevent air from passing up. From this box 9 the
liquid flows down a bent pipe h on to the trays i, i, of the carburetting
chamber B. The carburetting chamber, or carburator, as it may be called,
consists of a number of shallow trays, i, i, each holding a small quantity of

page_text: the liquid at the bottom. In the Drawing I have shewn only two trays.
It will be seen that if any excess of liquid beyond a given quantity comes
on to the first tray the surplus will run over the top of a pipe j, and pass
down the same on to the next tray below. These trays are all provided
with some porous material which has great capillary attraction, such, for
instance, as cotton thread, which is to be threaded up and down through
perforated tins k, l, k, k, placed about two and a quarter inches apart.
In the centre of the trays there is an inner chamber l, which is made of tin
or other metal perforated to within about half an inch of the top. The
outer rims or sides of the trays i, i, have holes perforated all round, from
the distances of of an inch from the top and two inches from the bottom;
that is, leaving a part plain above and below the perforations. The air or
gas may be made to pass from the outside towards the centre, or from the
centre to the outside. In the Drawing the air or gas as indicated by the
arrows is shewn as passing from the outside to the inside of the lowermost
tray, then up through the tube to the tray above, thence outwards. In
its passage in this manner the air or gas will pass over a large surface of
thread that is kept damp by the liquid, and in so doing will take up and
absorb a considerable quantity of the volatile hydrocarbon. The short
pipes in the trays stand about half an inch above the bottom of each tray.
in the centre, so that the liquid being the same height in the centre
chamber as in the other part of the tray, as soon as the liquid in the first
or upper tray gets to its proper depth it will overflow and pass down this
tube to the next tray. The bottom tray is not provided with the pipe j,
as if it got too full the overplus would flow over the side perforations into
the chamber below, which will be presently described. Down the centre
of the apparatus a pipo m passes from the top of the reservoir to near the
bottom of the lower tray. This pipe m is termed the air pipe, and when
the lower tray gets short of liquid the pipe m admits air to the top of the
reservoir A, and allows liquid to slowly descend through the valve b and
pipe h until the deficiency is supplied. When the bottom end of the tube
m is sealed by the liquid in the lower tray i no more liquid can flow into
the carburetting chamber. It will be understood that the upper trays, if
there are more than one, must cach in their turn get full to the top of the
little overflow pipes j before any liquid can reach the bottom, and as the
bottom tray is the one in which there is by far the greatest evaporation
(being the one through which the air or gas first passes) there is always a
slow flow of the liquid to it, which on its way keeps all the other trays
supplied. Between the bottom of the reservoir A and the top of the

page_text: carburator B there is a space which receives the air from the upper tray,
whence it goes into the outlet pipe n, which opens immediately below the
bottom of the reservoir. The lower trays have tops or covers, as shewn in
the Drawing, and which fit inside the rim, and are cut out in the centre to
the size of the inner chamber 1, so that the tops fit in and allow the rim, both
of the outside and inner chamber, to pass above them. Below the lower
tray a space is left to catch any liquid which may flow down beyond the
proper supply; such an accidental overflow may be caused by the filling.
plug or cap not being screwed down securely, or by the apparatus being
tilted accidentally. This lower chamber may be provided with a small
draw-off plug on a level with the bottom, so that any accumulated surplus
fluid may be drawn off so as not to impede the passage of the gas or air
through the apparatus. The inlet' n' enters this chamber immediately
below the lower tray, so as to allow about an inch between it and the
bottom of the carburetting chamber for the overflow to lie, so as to leave
the inlet n¹ clear of any liquid that may have accumulated in the bottom
of the apparatus. When the apparatus is used for carburetting air, the
cold produced by evaporation is so great that the body of the apparatus
must be surrounded with a jacket of warm water, the temperature of which
may be kept up by a small burner jet or by other suitable means. This
warm water is not used for producing the evaporation of the liquid, but
simply to keep the apparatus at the temperature of the air.
Having now described my Invention of "Improved Apparatus for Car-
buretting Air, and Gas," and having explained the manner of carrying the
same into effect, I claim as the Invention secured to me by Letters Patent
as aforesaid, the general construction and arrangement of apparatus herein
shewn and described for carburetting air and gas.
In witness whereof, I, the said Edward John Cowling Welch, have
hereunto set my hand and seal, the Eleventh day of August, in
the year of our Lord One thousand eight hundred and sixty-six.
Witness,
CHAS. RICHARDS,
1, Bridge Road,
Haverstock Hill.
EDWARD J. C. WELCH. (L.S.)