Year: 1887

page_text: I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:
This invention relates to that class of lamps in which the wick is of tubular form,
with an air tube or passage within the wick, and through which air flows to aid in
the support of combustion and commonly called "Central Draught Lamps," this
invention being an improvement on what is known as "The Rochester" lamp.
In this lamp and lamps of this class, the inner tube is provided with an extension
above the top of the wick, which extension is closed at the top, but has its sides per-
forated to form a distributor for the air which passes up through the central tube to
cause it to flow evenly to and upon the inside of the flame.
.
As heretofore constructed, this extension of the inner tube or central draught
passage has been in the form of a cup or thimble, the sides of which are perforated,
the thimble being introduced into the inner tube with the closed end uppermost, the
said thimble being also somewhat less in diameter than the draught tube, but con-
structed with a flange at its lower edge which will closely fit the inner surface of the
draught tube, so that it may be supported in the inner tube. This thimble is
necessarily removable, both for convenience of manufacture, and for convenience of
trimming the wick.
In replacing the thimbles, as after trimming, unless care be exercised to bring it
into a truly concentric or axial position, that is, if it stand inclined to the axis of the
draught tube, the perforations on one side will be brought nearer the flame than upon
the opposite side, the result of such misplacement of the thimble being such an
imperfect supply of air to the flame as to cause it to burn irregularly or imperfectly,
and frequently to smoke. Again, the upper end of the wick, or base of the flame is

page_text: necessarily above the top of the inner tube, and the supply of oil is frequently in
excess of consumption, or when not burning, if the wick stand with its end above the
inner tube, absorption will draw the oil through the wick to the top, and it naturally
escapes over the inner end of the draught tube. As this draught tube is neces-
sarily open at the bottom for the admission of air, it therefore follows that oil passing
into this tube will flow down, and upon the table or rest below.
The object of this invention is to overcome these difficulties, and it consists
principally in constructing the thimble as an auxiliary tube, adapted to pass down upon
the outside of the draught tube, and so as to surround the tube with sufficient bearing
to ensure its concentric or axial position when in place, and whereby the oil drawn
up by the wick, as before described, will pass through said auxiliary tube, and then
down between it and outside the inner tube, and thence return to the fount.
In the accompanying drawing
:-
Figure 1 represents a vertical central section of the central draught tube, the
auxiliary tube and its extensions, with so much of the burner and fount as are necessary
to the understanding of the invention.
Figure 2 is an upper end view of the central draught tube, and
Figure 3 is a side view of the upper end portion of the central draught tube,
illustrating the method of forming passages between the auxiliary tube and the
draught tube for the return of oil to the fount.
A represents the fount, and B the inner or central draught tube, the external
diameter of which corresponds substantially with the internal diameter of the wick,
so as to form the inner wick tube. Only a portion of the burner is shown, more
being unnecessary, nor is the wick adjuster shown, that being also unnecessary to
understand the invention.
D represents the tube, which is formed as a part of the barner, and which extends
down outside the, wick, so that the wick chamber is a concentric space between the
draught tube B and the outer tube D.
The
In the best construction of the invention, the upper end of the tube B is turned
inward, or contracted, as at a. 6 represents the auxiliary tube, the internal diameter
of which corresponds to the external diameter of the draught tube B, so as to slide
down over the upper end of the tube with substantially frictional contact.
auxiliary tube is closed at its upper end, and the sides of the extension of the
auxiliary tube above the upper end of the wick tube are perforated, as shown, to form
a concentric air distributor, so that air which passes up through the draught tube B
will escape through the air distributor radially against the inside of the flame. This
auxiliary tube is made of thin metal, so as to readily set between the wick and the
draught tube without hindrance to the proper adjustment or movement of the wick.
The upper end of the auxiliary tube is best made of less diameter than the central
tube B, it is therefore contracted through that portion which is to be perforated, so as
to form a shoulder d, which may rest upon the upper end a of the inner tube B, as
seen in Figure 1. The shoulder of the, auxiliary tube is perforated, the perforations
opening onto the inwardly turned or contracted end of the inner tube, so that
oil escaping from the wick, may pass through the perforations in the shoulder
onto the outer surface of the draft tube, and as it comes upon the draft tube below its
upper end, flow down between the auxiliary tube and the draft tube, and return to
the fount from whence it came.
While the oil will pass between the two tubes, even with so close a fit between the
two tubes that the tube will be supported by frictional contact, to insure the proper
escape of the oil, the draught tube should be constructed with one or more vertical
channels e see Figures 2 and 3, these channels being made by making vertical
indentations or corrugations in the surface of the tube around its upper end, the
grooves extending down to a point below the auxiliary tube, so that they form free
passages for the oil between the two tubes. It is preferred to make the perforated
extensions, or air distributor portion of the auxiliary tube of less diameter than the draft
tube, both for the purpose of forming a secure bearing or rest for the auxiliary tube,

page_text: as well as for effecting a better distribution of air to the flame than would be accom-
plished by making the perforated portion of equal diameter with the auxiliary tube.
But the perforated extension may be of equal diameter, as indicated by broken
lines Figure 1 in which case there should be a rest formed on the inner tube, say as
at broken lines Figure 1 upon which rest the auxiliary tube may stand, so that
its proper elevation will be insured.
By the construction which is described, the proper location of the auxiliary tube
is insured, for the reason that it cannot be wrongly inserted, nor can it be applied
other than in a truly concentric or axial position. Again, by making a passage or
passages downward between the inner or central draught tube, and the auxiliary
tube, the overflowing oil is securely reconveyed to the lamp fount, and thus the
difficulties which are mentioned as existing in the "Rochester" and similar lamps
are avoided.
It is to be understood that this invention is not broadly for an auxiliary or air
distributing tube, having its upper end reduced in diameter so as to form an annular
shoulder on said auxiliary tube, as such is a common and well known construction,
the essential feature of the invention being the construction of the auxiliary or air
distributing tube so as to set over the end of the inner wick tube, and extend down
into the wick chamber, in order that the joint between the inner wick tube and
the auxiliary tube may open into the wick chamber instead of into the air tube, as in
previous constructions.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed as communicated to me by my
foreign correspondent I declare that what I claim is :—
First. In a tubular wick or central draught lamp, the combination of a central
draught tube forming the inner wick tube, open for the admission of air; and an
auxiliary tube, the internal diameter of which corresponds to the external diameter
of the said inner tube, and adapted to set over the upper end of said inner tube,
the said auxiliary tube being constructed with an extension above the inner tube, of a
diameter less than the diameter of the said inner tube, so as to form an annular
shoulder as a rest upon the upper end of the inner tube, the sides of said extension
being perforated to form an air distributor, substantially as described.
Second. In a tubular wick or central draught lamp, the combination of a central
draught tube forming the inner wick tube, and an auxiliary tube adapted to set over
the upper end of the said inner tube. and constructed with an extension above the
end of said inner tube, the auxiliary tube being closed at its upper end, the sides of
the extension perforated to. form an air distributor, and the said tubes constructed
with one or more passages between them, leading downward to the oil reservoir,
substantially as described.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.