IMPROVEMENTS IN THE CONSTRUCTION OF LAMPS FOR BURNING MINERAL OILS
Year: 1879

page_text: LETTERS PATENT to John Thomas, of Holloway, in the County of Middlesex,
for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF LAMPS FOR
BURNING MINERAL OILS"
Sealed the 7th November 1879, and dated the 13th May 1879.
PROVISIONAL SPECIFICATION left by the said John Thomas at the Office
of the Commissioners of Patents on the 13th May 1879.
JOHN THOMAS, of Holloway, in the County of Middlesex.
THE CONSTRUCTION OF LAMPS FOR BURNING MINERAL OILS."
"IMPROVEMENTS IN
This Invention consists in improvements in the construction of lamps for burning
mineral oils, and relates principally to lamps employed for railway, shipping, and
other purposes where they are exposed to the influence of violent winds and
draughts of air. By the use of the said improvements the liability of the flame to
be extinguished or to be injuriously affected by the said winds or draughts of air is
entirely avoided, the combustion of the oil is greatly facilitated, and amongst other
advantages the reservoir is protected or insulated from the heat generated by the
flame.
The oil reservoir, which is constructed of any suitable metal and of any desired
size or shape, forms the base of the lamp, and has mounted thereon, by means of
hollow perforated pillars, the double or hollow bottom of the body of the lamp.
The latter, which is of any desired shape, but by preference of a square or octagonal
section with the flat sides, is hinged to the said double or hollow bottom, and when
closed thereon is fastened by means of a spring catch. One or more of the sides of
the case or body of the lamp may be glazed, and if desired formed as doors. The
wick-holder is fixed on the upper part of the double bottom, and a little distance
above the latter, and fixed within the interior of the case or body, is a false bottom
having an aperture in the centre thereof for the wick-tube to pass through, the
cone or deflector being mounted round the said aperture in the false bottom, as will
be well understood. The wick-holder is surrounded by a perforated cylinder or
band of metal which is attached to the false bottom, the number and size of the
perforations corresponding with those in the chimney hereinafter described.
The top and sides (those which are glazed or which form doors being excepted)
of the case or body of the lamp are made hollow by means of an internal lining,

page_text: the air chamber thus formed opening at the lower part thereof into the space
between the false and double bottoms. Projecting a little below, and passing
through the top of the internal lining of the lamp, is the chimney which is closed
at the top but has the sides provided with a suitable number of apertures for the
escape of the products of combustion. Surrounding the said chimney is an outer
casing attached to the top of the outer case of the lamp, the space so formed
between the chimney and outer casing opening into the hollow top of the case
or body. In some cases the top of the said outer casing is terminated by a
number of perforated metal plates fixed horizontally and parallel to, and at a little
distance from each other. This arrangement allows of the wind passing through
without meeting with any resistance, and therefore facilitates the escape of the
products of combustion. Or in some cases I terminate the top of the said outer
casing by means of a series of circular bands constructed of an inverted truncated
conical form. The said bands, which are fixed vertically above each other, do not
correspond in shape but are made with different angles of inclination, the angles
increasing from the bottom.
In lamps which have all their sides glazed, or some glazed and the remainder
forming doors, the air chamber or space formed by the hollow-top is placed in
communication with the air space at the bottom of the lamp by means of hollow-
tubes or pillars which may form the supports between the various glasses of the
sides.
The lamp is provided with a number of air valves for regulating and controlling
the ingress and egress of air to the same when exposed to winds. These valves
consist of suitable perforations made in certain parts of the lamp as hereinafter
described, such perforations being covered on the inside with thin plates of mica or
tale so suspended as to move easily when acted upon by a current of air passing
through the said perforations. The perforations are made in any of the sides of the
lamp forming part of the hollow air chambers or space. The outer casing surrounding
the chimney is in some cases constructed with flat sides which are perforated,
and valves formed as above described; or it may be round, in which case it is
perforated and bas arranged and fixed around the interior thereof a series of flat
perforated plates forming, with the mica or talc, valves as before described, and
through which valves the air must pass before entering the air space or chamber.
When considered necessary or desirable air chambers may be formed at the top or
bottom of the lamp by fixing together a number of plates fixed vertically or nearly
so, and provided with valves constructed as hereinbefore described. It will be
readily understood that the said valves wherever used should be arranged uniformly
all round the lamp, and also in those parts which are vertical or nearly so, in such
a manner that from whatever direction the current of air may come it will be free
to enter the air chambers or air space of the lamp. The wind entering at one side
closes the valves on the opposite side by acting on the talc, thus preventing the
escape of the air when it has once entered. The before mentioned pillars supporting
the double or hollow bottom allow of the admission of air to the latter, whence it
passes into the air space below the false bottom, and by these means the communi-
cation of heat to the oil reservoir is prevented. Instead of employing the pillars
herein before mentioned the oil reservoir is in some cases insulated for effecting the
desired object by connecting it to the case or body of the lamp by short lengths of
cat-gut, the ends of the same being connected to the respective surfaces of the case
or body and reservoir by collars. In cases where the limited amount of space will
not admit of the employment of the said pillars or cat-gut, I rivet plates of mica or
talc to the underside of the double bottom, angle pieces of metal being affixed to
the said plates for the purpose of attaching the oil reservoir.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Thomas in the Great Seal Patent Office on the 13th November
1879.
JOHN THOMAS, of Holloway, in the County of Middlesex.
THE CONSTRUCTION OF LAMPS FOR BURNING MINERAL OILS."
"IMPROVEMENTS IN
My said Invention consists in improvements in the construction of lamps for
burning mineral oils, and relates principally to lamps employed for railway, shipping,
and other purposes where they are exposed to the influence of winds. By the use
of the said improvements a sufficient supply of air to the interior of the lamp for
the purpose of supporting the combustion of the oil is effected in such a manner
that the liability of the flame to be extinguished by the exhaustion of air, or from
the action of the wind or violent draughts of air, is entirely avoided, whilst amongst
other advantages possessed by lamps constructed in accordance with this Invention
is the protection or insulation of the oil reservoir from the heat generated by the
flame.
Hitherto lamps of the class above referred to for consuming mineral oils have
been generally constructed so that no wind or draught shall enter the interior
thereof; one consequence of such arrangement is that an exhaustion of air takes
place when exposed to a current of air, and that exhaustion frequently becomes so
great that the flame is extinguished. By experiment I have found that this
principle is erroneous, and I avoid the disadvantages attendant thereon by con-
structing lamps in such a manner that the entrance of air to the interior thereof is
encouraged by means of valves and other apertures, and the exhaust counteracted
as much as possible.
The lamps are constructed as follows:-The oil reservoir, which is constructed of
any suitable metal and of any desired size or shape, constitutes the base of the
lamp, and has mounted thereon by means of hollow perforated pillars the double or
hollow bottom of the lamp. The body of the latter, which is of any desired shape,
but by preference of a square or octagonal section with flat sides, is hinged to the
said double or hollow bottom, and when closed thereon is fastened by means of a
spring catch. One or more of the sides of the case or body of the lamp may be
glazed, and if desired formed as doors. The wick tube passes through the hollow
bottom to which is fixed the wick holder. A little above the hollow bottom, and
fixed within the interior of the case or bottom, is a false bottom having an aperture
in the centre thereof for the wick tube to pass through, the cone or deflector being
mounted round the said aperture in the false bottom. The wick holder is surrounded
by a perforated cylinder or band of metal which is attached to the underside of
the false bottom, the number and size of the perforations. corresponding with those
in the chimney hereinafter described.
The top and sides (those which are glazed or which form doors being excepted)
of the case or body of the lamp are made hollow by means of an internal lining,
the air chamber thus formed opening at the lower part thereof into the space
between the false and double bottoms. Projecting a little below, and passing through
the internal lining of the top of the lamp, is the chimney which is closed at the upper
end, but has the sides provided with a suitable number of apertures for the escape
of the products of combustion. Surrounding the said chimney is an outer casing
attached to the outer case of the top of the lamp, the space so formed between the
chimney and outer casing opening into the hollow top of the body of the lamp.
The casing surrounding the chimney is terminated by a series of circular bands
constructed of an inverted conical form, all but the top band being truncated. The
said bands, which are fixed vertically above each other, do not correspond in shape,
the sides thereof being inclined at different angles, the angles of inclination of the
sides of the truncated cones increasing from the lowest. This form of construction
tends to deflect the current of air from the exterior into the interior of the lamp,

page_text: and thereby assists in retarding the exit of air and products of combustion, and
thus prevents a too rapid exhaustion. Although the outer case of the chimney is
referred to as being terminated as above described I do not desire to confine the
other portions of this Invention to the employment of that arrangement, as any
suitable and known mechanism may when desired be used.
The lamps constructed as herein before described are provided with a number of
air valves for regulating and controlling the ingress and egress of air to the same
when exposed to winds. These valves consist of perforations made in certain parts
of the lamp, as hereinafter described, such perforations being covered on the inside
with thin plates of mica or tale so suspended or hinged as to move easily when
acted upon by a current of air passing through the said perforations.
The per-
forations are made in any of the sides of the lamp forming part of the hollow air
chambers or space.
The outer case of the chimney is in some cases constructed
with flat sides which are perforated, and valves formed as above described; or it
may be made round and perforated, a series of flat perforated plates, forming with
the mica or talc valves, as before described, being arranged and fixed round the
interior thereof, the air passing through the said valves before entering the air
space or chamber.
When considered necessary or desirable air chambers are formed at the top or
bottom of the lamp by fixing together a number of plates arranged vertically or
nearly so, and provided with valves constructed as hereinbefore described.
It will be readily understood that the said valves wherever used should be
arranged uniformly all round the lamp, and also in those parts which are vertical
or nearly so in such a manner that from whatever direction the current of air may
come it will be free to enter the air chamber or air space of the lamp. The wind
entering at one side closes the valves on the opposite side by acting on the talc, thus
preventing the escape of the air when it has once entered.
The before mentioned hollow perforated pillars supporting the double or hollow
bottom allow of the free circulation of air through the same into the air space below
the false bottom, and by these means the communication of heat to the oil reservoir
is prevented.
Instead of employing the pillars lastly hereinbefore mentioned the oil reservoir is
in some cases insulated by connecting it to the bottom of the lamp by short lengths
of stout cat gut, the ends of the same being connected to the respective surfaces of
the bottom of the lamp and the reservoir by suitable collars.
In cases where the limited amount of space will not admit of the employment of
the said pillars or cat gut I rivet plates of mica or talc to the underside of the double
bottom, angle pieces of metal being affixed to the said plates for the purpose of
attaching the oil reservoir.
I will now proceed to refer to the accompanying Drawings, from which the nature
of my said Invention will be more clearly understood. The same letters of reference
indicate like parts in the several Figures.
Figure 1 is an elevation of a lamp constructed as firstly hereinbefore described,
Figure 2 is a vertical section of the same, and Figure 3 is a transverse section
taken through the line × ×, Figure 1.
A is the oil reservoir which is provided with the ordinary plug for filling, and
has a rim A¹ in the centre surrounding the wick tube for the purpose of preventing
the oil overflowing or splashing out when the lamp is being moved about; B is the
lamp case or body which is connected to the hollow bottom C by the hinge B¹; B²
is a spring catch; B³ are glass sides which may be arranged to open like doors, or
they may slide in grooves; C is the double bottom, in the centre of which is fixed
the wick tube holder C¹; D is the wick tube; E is the false bottom; F, the cone
or deflector; G is the perforated cylinder or band of metal surrounding the wick
holder, and which is attached to the false bottom in order that it may not be in the
way when it is desired to light or trim the wick; the perforations in this cylinder
correspond in number and size with the perforations in the chimney K; H is the
internal lining which, together with the false bottom, forms the flame chamber E¹;

page_text: J is the air chamber or space connecting the air spaces at the top and bottom of
the lamp. The top of the chimney K is closed, and the number and size of the
perforations in the body thereof are regulated according to the size of flame required,
and they correspond with those in the perforated cylinder or band G, so that whatever
pressure of air may be in the space J by reason of the wind entering the valves
hereinafter described it will not affect the flame, as the pressure will be equal. at the
top and bottom. L is the outer case of the chimney attached to the upper part of
the case B; M is the top of the chimney hereinbefore described formed of a number
of inverted cones having, with the exception of the top, the apices cut away; these
cones are supported one above another by means of bars or short metal tubes M¹.
In the latter case a pin or rivet passing through holes made in the flange part of
the cones and through the tubes is riveted or turned over at the top and bottom.
P are the valves hereinbefore referred to, constructed by suspending plates of mica
or talc P¹ behind suitable perforations P made in certain parts of the lamp case or
chimney in such a manner that when the wind blows through the perforations the
plates P¹ will be blown inwards and will allow the wind to enter, at the same time
the valves on the opposite side will be closed by the pressure of the current of air on
the inside of the said plates. By these means the air is confined within the lamp,
thus tending to produce a pressure of air, thereby counteracting the exhaustion of
the air which is usually the cause of the extinguishing of the flame when lamps, as
ordinarily constructed, are exposed to the wind. R are perforated hollow pillars
which are fixed on the oil reservoir and serve to support the body of the lamp.
Air is admitted through the perforations to the interior of the lamp, the passage of
the same through the pillars keeping the latter cool, thereby preventing the trans-
mission of heat to the reservoir.
Figure 4 is an elevation, Figure 5 a vertical section, and Figure 6 a cross section
through the line T, T, in Figure 4, of another form of lamp having all its sides
glazed. The air communication between the top and bottom of the lamp is effected
by means of hollow pillars V formed of metal, and which constitute the corners of
the flame chamber. The air valves P are shown in these Figures in the lower part
of the lamp case, air passing through the same to the flame. In Figure 5 the valves
are shown open at one side and closed at the opposite side, the reverse position of
the same being indicated by dotted lines. The body of the lamp is shown supported
by means of pillars S made of short lengths of cat gut, on to the ends of which are
screwed metal collars for the purpose of attachment to the reservoir and to the
body of the lamp. These pillars are perfect non-conductors of heat and are
exceedingly strong.
The arrows in the Drawings show the direction of the air, the passage of the
products of combustion being indicated by dotted arrows.
Having thus described and ascertained the nature of my said Invention, and the
manner in which it is to be performed, I would observe in conclusion that I do not
desire to restrict the same to the precise details herein before stated, as they may be
varied and modified without departing from the principles thereof, but what I
consider novel and original, and therefore claim as constituting the Invention
secured to me by the said hereinbefore in part recited Letters Patent arc,-
First. The construction and arrangement of the air valves of lamps of perforated
plates and plates of mica and talc, substantially as hereinbefore described and set
forth.
Secondly. The construction and arrangement of the chimney tops of lamps by a
combination of inverted cones, substantially as hereinbefore described and set
forth.
Thirdly. The construction and arrangement of hollow perforated pillars for sup-
porting the case or body of lamps, substantially as and for the purposes hereinbefore
described and set forth.
Fourthly. The employment of cat gut pillars, substantially as and for the purposes
bereinbefore described and set forth.

page_text: And, lastly. The combinations and arrangements of mechanism, substantially as
and for the purposes hereinbefore described and set forth.
In witness whereof, I, the said John Thomas, have hereunto set my hand
and seal, this Twelfth day of November, in the year of our Lord One
thousand eight hundred and seventy nine.
TATT15 MTTAULA
JOHN THOMAS. (L.S.)