IMPROVEMENTS IN PRODUCING LIGHT
Year: 1842

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PIERRE
PELLETAN, of Bedford Square, in the County of Middlesex, Gentleman, 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 Second day of November, in the sixth year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said Pierre
Pelletan, Her especial licence, full power, sole privilege and authority, that I,
the said Pierre Pelletan, my exors, adiñors, and assigns, or such others as I,
the said Pierre Pelletan, my exors, adñors, 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, my
Invention of "IMPROVEMENTS IN PRODUCING LIGHT;" in which said Letters
Patent is contained a proviso that I, the said Pierre Pelletan, shall cause
a particular description of the nature of my 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, I, the said
Pierre Pelletan, do hereby declare the nature of my said Invention, and
the manner in which the same is to be performed, are fully described and

page_text: ascertained in and by the following statement thereof, reference being had to
the Drawings hereunto annexed, and to the figures and letters marked thereon,
that is to say:-
This system of illumination consists of a mode of constructing apparatus for
obtaining a comdensible and inflammable vapour instead of a permanent gas
and applying the same to the purposes of distributing light. This inflammable
vapour is obtained by evaporating some one or more of those combustible and
volatile liquids which are obtained in great abundance, such as natural naptha
wood and coal naptha, turpentine, &c. &c. The vapour arising from the
distillation of such liquid or liquids is distributed through pipes by the
apparatus in which the vapour is generated, and in such manner as to obtain
a sufficiently uniform pressure throughout the whole system, notwithstanding
any variation in the quantity consumed, and even although its consumption
should cease entirely. In consuming the vapours of such fluids, burners,
such as are usually employed for common gas, are used, but the regulating
cock of the burner should be of a peculiar kind, as will be hereafter described.
The nature or composition of the flame can be modified at will by varying the
composition of the combustible liquid employed. The apparatus is composed
generally of a small boiler set in a furnace, from whence the vapour. is con-
veyed through a horizontal main, both ends of which communicate with the
boiler in order that all condensed liquid that may form in the horizontal main
shall flow back into the boiler to be re-evaporated. In connection with this
horizontal main are fixed the pipes that supply the burners. The following
description and Figures 1, 2, and 3 of the Drawing No. 1 will give a correct
account of the apparatus:-A, A, represents the brickwork in which the boiler
is set. B, fire grate. C, a metal plate, which, when the fire door is closed, is
forced up into an inclined position so as to direct the fuel from the hopper F
on to the fire bars, and when the fire door is opened this plate can lay flat.on
the fire plate, in order to draw the fire, &c. D, fire door. E, ash pit, closed
in front by a door, with a register to admit more or less air to the ash pit, or
to intercept its passage, as required. F, hopper set in the brickwork through
which the fire fed, its upper opening being closed by an horizontal plate or
otherwise. G, the back part of the flue communicating with the chimney
H, H, to carry off the smoke. H, H, chimney. I, a register valve keyed on
the spindle I', and worked by the lever J, J. K, counterweight suspended
from the end of the lever J, J, in order to regulate the power of L. L, the
float contained in M', and intended to regulate the draft by opening and
shutting the valve I. M, M', two pipes connected together at their lower
extremities, and being about half full of water or any other liquid. M' is open

page_text: at top and contains the float L. M is closed at top, and is connected with the
upper part of the boiler by two pipes 0, 0, the lower pipe O being intended
to regulate the height of the water in these pipes, where there is no pressure
in the boiler, and both serving to enable the vapour in the boiler to exercise
its full pressure upon the surface of the liquid in the pipe M, which forces the
water and the float L to rise in the pipe M', by which means the register
valve I gradually closes, and damps the fire by diminishing the draught.
P, P, the boiler or generator. Q, Q, flanch of the boiler with the lugs, with
holes r, r, r, to receive the standards 3, 3, 3, that support the condenser X, X.
R, R, the cap of the boiler fixed by bolts or screws 8, 8, s, to the flanch Q, Q.
S, S', wrought iron pipe, closed at each end by flanches; this pipe passes through
the fireplace about halfway between the bottom of the boiler and the fire bars;
the vapour from the boiler passes through it, entering at the end S, and escaping
through the pipe T into the horizontal main that supplies the burners. By
this arrangement the vapour after quitting the boiler becomes heated, and con-
sequently less subject to condensation. U, U', pipe to convey the vapour from
the boiler into the pipe S, S'. V, regulating cock to determine the flow of vapour
into the horizontal main, and to eut it off entirely when required. X, X,
reservoir acting as a condenser, through which runs a small quantity of water;
this condenser contains a small metallic worm Y, Y, the upper end of which
is in communication with the pipe 4, through which arrives a constant
supply of vapour from the horizontal main. The lower end of this worm
communicates with the pipe 10, 11, the lower extremity of which descends
into and nearly to the bottom of the boiler, there discharging all the liquid
coudeused in the worm while its upper end 11 conveys into the chimney H
all the common air that may have been contained in the apparatus. 7 is
the return pipe of the horizontal main, through which returns all the
liquid that may have been condensed in the pipes, as also a considerable
quantity of vapour. The liquid and vapour are both thrown into the pipe 8,
which also dips into the liquid in the boiler and there discharges all the liquid
coming from the main, whereas the upper end terminates in the valve box. 5,
which contains a light valve to regulate the pressure in the horizontal main.
Above this valve the pipe 4 of the worm Y, Y, communicates with the valve
box 5, so as to convey into the condenser all the excess of vapour that has been
thrown in from the horizontal main, and, as before stated, the liquid obtained
in this worm by the condensation of that excess of vapour is conveyed into the
boiler by the pipe 10, and the air or permanent gas, if there is any, is carried
from the worm into the chimney by the pipe 11. 9, a pipe communicating
freely with the boiler, having also at its upper extremity the valve box 6, con-

page_text: taining a valve somewhat heavier than the valve in the box 5. Above this
valve in box 6 there is also a communication with the worm Y, Y, by the
pipe 4; the difference of the weight of these two valves determines a constant
flow of vapour through the main. This second valve 6 performs a very
important duty, therefore, for it not only effects this circulation, but in the
event of a great number or of all the lights being simultaneously extinguished,
or supposing the cock V to be shut, so as to prevent the passage of the vapour
through the horizontal main, thus the pressure would augment in the boiler
and the valve in the box x would be forced open, all the vapour produced
would pass into the condenser, and so return to the boiler in a liquid form
without any loss, the whole apparatus thus acting as a common still. By
placing a cock and branch pipe on any portion of the pipe 10, the distilled
liquid may be collected in a separate vessel, and the apparatus itself employed
to rectify the liquid or liquids required for the production of the inflammable
vapours. 12, a branch pipe, which, by opening through the cock 13, establishes
a communication between the boiler and the condenser, and is useful to allow
the escape of the air that may be contained in the apparatus at the commence-
ment of its operation, and the free passage of the vapour to the condenser
when the apparatus is used as a rectifying still, in which case the cock V
should, of course, be shut.
Having given the above description of the apparatus, I will now explain
its action more fully. When light is required, the boiler should be about half
filled, more or less, with liquid of a suitable nature to produce inflammable
vapour. The fire being lit, the hopper F is to be filled with fuel (coke, for
instance, in small lumps), the fire door and the orifice F of the hopper F
being closed and the register in the chimney open, the fire becomes active
and vapour will be rapidly generated and circulated through the horizontal
main, forcing the air through the valve 5 and through the worm Y, Y, into
the chimney H; by this means all the vapour contained in or carried off with
the air will be condensed and will fall into the boiler. The air being expulsed,
the pipe 7 will become heated, and then the apparatus is ready for action.
And I have found it advantageous to introduce a quantity of water in the
boiler about equal to the quantity of volatile liquid used, as it prevents
injury to the boiler and is otherwise advantageous. As the internal pressure
increases, the float L in the pipe M' will be gradually forced upwards until
the internal pressure will be able to support a column of about eight inches of
water, when the register valve I will be nearly closed, and the fire consequently
damped, so as to regulate the quantity of vapour generated. When the cock
of a burner is opened the air contained in the upright pipe coming from the

page_text: main will first escape and will be followed by the inflammable vapour, which,"
being ignited, burns like common gas, but without emitting sulphurous acid,
the liquid from which the vapour has been obtained not containing any sulphur.
The flame produced will be steady because several means concur to make the
pressure of the vapour, and so efficient are they that the pressure will not
be sensibly affected by the sudden simultaneous extinction of several lights,
and this principally because the quantity of vapour consumed is only taken
from a current of vapour which is constantly flowing through the horizontal
main into the condenser. The boiler in this system of lighting should be
placed sufficiently low to enable the liquid to run from the horizontal main
into the liquid in the boiler. The horizontal. main that feeds the burners
should be as much as possible protected against the action of external cold,
either by placing it in the floor or a wall, and by conveying it through a wood
or other trough, or by properly surrounding it by woollen list or any other bad
conductor of heat. Notwithstanding these precautions, a small quantity of
liquid may condense above the plug of the regulating cock of the burner, and
to avoid this inconvenience I have invented a peculiar kind of cock, a descrip-
tion of which I will now give as being part and portion of my patent appa-
ratus. The plug of this cock is placed vertically, and has a hole running
through it, as shewn in Figure 4, Drawing No. 2. The upper end, that
projects above the shell of the cock, carries an external thread to receive the
burner. The shell of the cock is closed by a plate soldered to the bottom,
and the upper end of the shell is fitted and soldered into the jacket 3. 0, 0, is
the hole through the plug, and the shell for the passage for the vapour to the
burner. The advantage of this arrangement is obvious, for the cock being
entirely envelloped by the vapour in the jacket, all condensation is prevented;
and if any liquid is carried into the plug from the jacket it naturally falls into
the bottom of the shell, from whence it is conveyed away by the pipe 5. 5 is
a small pipe soldered to the shell of the cock and terminating at bottom in a
reservoir 6, of a capacity equal to that of the pipe 5, or thereabouts. The
pipe 5 is made sufficiently long to contain a column of liquid capable of
resisting the pressure in the horizontal main. When there is no pressure the
whole of the contents of the pipe descends into the reservoir, and when there
is a pressure in the pipes the liquid from the reservoir is forced up to a certain
level in the pipe 5, and thus an hydrostatic joint is formed. The pipe 5 should
be enclosed in a wooden jacket or some other nonconducting material, to prevent
the heat in the surrounding vapour from evaporating the liquid in the pipe.
This cock will, therefore, entirely free the burner from liquid, and as no accu-
mulation can take place in the pipe 5 above a certain level, all the surplus will fall

page_text: into the horizontal main, and will run from there into the boiler. When hanging
lights are required, a peculiar arrangement of the lampsmust be adopted, or
account of the small quantity of liquid that will condense in the vertical pipe
and which, if not got rid of, would accumulate in the lower branch. I propose
to remove this difficulty by means of a centre light so placed as to heat a
small reservoir in the form of a vase, placed immediately under the vertical
pipe, and which light may be either concealed or apparent. If concealed, a
cup or vase F, Figure 5, may be placed under the vertical pipe, into which
the condensed liquid may fall. By making this vase in two separate parts,
the upper one forming the reservoir for the liquid, as seen at f.f, and a small
pipe d so placed as to bring a small quantity of vapour from the top of the
vase, so as to form a burner under the bottom of the vase F. Thus the heat
of this burner will evaporate the liquid contained therein, and the bottom
part of the vase being perforated by small holes to supply the combustion,
may be so attached to the upper part as to conceal the light entirely. If
made apparent, I propose placing a central Argand burner unider the
reservoir F, by which means the condensed liquid will be most effectually
carried off, and a very ornamental effect might be produced.
Having fully described the whole of the apparatus, and the method of
working it, I will now point out the particular parts of this Patent that I
intend to reserve as being of my Invention.
First, the mode of arranging apparatus for distribution of light, at various
points distant from each other and from the apparatus, by means of an inflam-
mable vapour instead of a permanent gas as hitherto employed for that
purpose.
Secoudly, the means of obtaining a superabundant current through a
system of pipes, and of producing and condensing continually the inflammable
vapour in such a manner that the jets of vapour in the burners do not sensibly
affect the pressure in the pipes or the working condition of the apparatus,
whatever may be the variation in the consumption, and even when the
consumption is entirely stopped.
Thirdly, the method of regulating the fire by the internal pressure in the
boiler, as applied to the production of light, and by means of a liquid perfectly
independant of that contained in the boiler.
Fourthly, the heating of the vapour after its production in the boiler, by s
passing it through a tube or vessel, by which means condensation to a certain
extent is prevented.
Fifthly, the application of a double conveyance of the vapour from the
boiler to the condenser, so disposed that one is sufficient to answer ordinary

page_text: purposes, the second being brought into action only when the supply of vapour
becomes too great, or in consequence of its having been cut off from the
horizontal main, by which the ordinary conveyance is closed.
Sixthly, the condensation of all the superabundant supply of the vapour
over and above what is consumed, by which means the whole of the
vapour produced can be re-introduced to the boiler in a liquid form
without loss.
Seventhly, the mode of constructing what I call the hydrostatic cock for
the burners, so combined that all the liquid condensed in or conveyed into
the cock or burner shall return by its own gravity into the boiler.
Eighthly, the application of heat to prevent the accumulation of liquid in
the suspended lights.
In witness whereof, I, the said Pierre Pelletan, have hereunto set my
band and seal, this First day of May, in the year of our Lord One
purposes, the second being brought into action only when the supply of vapour
becomes too great, or in consequence of its having been cut off from the
horizontal main, by which the ordinary conveyance is closed.
Sixthly, the condensation of all the superabundant supply of the vapour
over and above what is consumed, by which means the whole of the
vapour produced can be re-introduced to the boiler in a liquid form
without loss.
Seventhly, the mode of constructing what I call the hydrostatic cock for
the burners, so combined that all the liquid condensed in or conveyed into
the cock or burner shall return by its own gravity into the boiler.
Eighthly, the application of heat to prevent the accumulation of liquid in
the suspended lights.
In witness whereof, I, the said Pierre Pelletan, have hereunto set my
hand and seal, this First day of May, in the year of our Lord One
thousand eight hundred and forty-three.
P. (L.B.) PELLETAN.
AND BE IT REMEMBERED, that on the First day of May, in the year
of our Lord 1843, the aforesaid Pierre Pelletan, Esq, came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that purpose.
Enrolled the Second day of May, in the year of our Lord One thousand
eight hundred and forty-three.