Year: 1885

page_text: I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of this Invention (a communication to me
from abroad by John Edward Birch (Tinsmith) and Donald Henderson (Physician)
both of the City of Winnipeg in the province of Manitoba and Dominion of
Canada) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The object of this invention is to provide a gas burner which will automatically
cut off its flow of gas whenever the flame from any cause becomes extinguished.
Sometimes when water or air gets into the gas pipes the flame will become
extinguished, and the gas will afterwards continue to flow; or the gas may be
extinguished by shutting off the meter at night so that when the gas is turned on
again in the morning, gas will commence to flow through cocks which have
been left open at night. Ignorant persons, too, frequently incur the same risk by
blowing out the gas instead of turning it off at the cock.
This invention is designed to obviate the dangerous consequences of such
contingencies by means of a gas burner which is self closing when the flame is
extinguished and for which purpose I make use of the expansibility of a confined
body of air which when expanded by the normal heat of the burner, holds open a
valve that permits the flow of gas to continue and which body of air when cooled
by the extinguishment of the flame contracts and closes the valve thus cutting off
the flow by a positive and certain action.
. The invention consists in the peculiar construction and arrangement of parts
operating on this principle as will hereinafter be more fully described.
Reference is to be had to the accompanying drawings forming part of this
Specification in which
Figure 1 is a vertical central section showing the parts in the position which
they assume just as the illuminating jet is about to be ignited Figure 2 is a
sectional view showing the opening of the valve k by the excessive rise of cylinder h.
A

page_text: In the drawing a represents the outer case of the burner which may be of any
approved shape and which at its lower end is screw threaded as at to permit it
to be screwed in the usual way to the threaded nipple of the gas bracket. The
upper end of this case is enlarged at e and screw threaded interiorly to fit an
external screw thread of a cap c which closes the upper end of the case and has a
central nipple to receive the ordinary lava or metal tip d.
Upon the shoulder of the lower part of the section c is sustained a cylindrical
air cell or pocket f. made of metal and having a flange i at its top by which it is
sustained in position in the case, which cell is closed at the bottom and open at the
top. This flange i has a series of small holes o through it that communicate below
with the annular gas space between the outer case and the air cell and with the
gas space beneath cap c above which holes form conduits or passages through
which the gas reaches the top of the burner.
Within the air cell fa closely fitted cylinder is arranged which is closed at its
upper end and is provided with a flange that overhangs the perforated flange of
the air cell and forms a gas valve as hereafter described. The lower portion of
this cylinder is immersed in a mercury seal contained in the cell f and thus
imprisons a body of air in said cylinder.
The normal operation of this burner is as follows:-The air within cylinder / is
expanded by the heat of the burner and raising cylinder lifts its flange off the
holes o in the flange of the air cell and allows gas to pass from the annular space
around said air cell up to the tip of the burner which condition of things is main-
tained as long as the flame of the burner continues. As soon however as the flame
is extinguished the air within cylinder h cools and in contracting allows the
cylinder to drop down into the mercury and brings the flange of the said cylinder
tightly down upon the holes o which admit gas to the top thus automatically
cutting off the supply of gas.
To avoid the necessity of using so much mercury a tube or post g is placed in
the centre of the air cells and acts as a displacing body to maintain the height of
the mercury and reduce its bulk. To open the cylinder valve and allow the gas to
issue in first lighting, a supplemental jet is provided by a tube n² and a conduit n
in which tube plays a short stem having a valve on the inside and a push
button 8 on the outside provided with suitable packing washers and around this
stem a spiral spring coiled.
By pushing button s in, as shown by the finger, valve r is opened and a jet of
gas is allowed to issue which being ignited heats the air in cylinder h, and this
body of air in expanding lifts the flange valve at the top of the cylinder which
allows the gas to issue through the holes o which gas continues to issue and burn.
After this the pressure on button s is discontinued and the air in cylinder h is
kept expanded by the heat of the gas jet at d.
If the heat of the burner is so great as to produce an undue expansion of the air
and excessive elevation of the cylinder a valve le is made to open in the top of
the cylinder automatically and allow some of the air to escape. This is effected as
follows. A screw threaded adjusting bar m on the stem of valve k strikes the
cap c as cylinder h rises too high (see Figure 2) and forces the valve down against
the tension of bow spring thus opening the valve and allowing it to be closed
again when the excessive expansion has been relieved.
To regulate or vary the flow of gas through holes o in flange i a ring with
corresponding holes is placed beneath the Hange and is turned at will to cut off
more or less of the gas passing through.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is
1st An automatic cut off burner consisting of an outer gas chamber provided
with a tip, an expansible air chamber located therein and formed of two parts
sealed with mercury one of said warts being provided with a flance and the other

page_text: with a set of holes to constitute with. said flange a valve which is opened and
closed by the expansion and contraction of the air within the air chamber sub-
stantially as described.
2nd In an automatic cut off burner the combination with a gas burner of a valve
provided with an expansible air chamber and a supplemental jet in close proximity
to the burner and air chamber, whereby the lighting of said supplemental jet will
produce the initial expansion of air and start a flow of gas through the burner
substantially as described.
3rd In an automatic cut off burner the combination with a gas burner of a gas
valve connected to the movable part of an expansible air chamber, an escape valve
located in the movable part of the expansible air chamber and having an operating
arm extending to a point near the gas burner whereby it will be operated by an
undue expansion of the air in said chamber by contact with the burner as set forth.
4th The combination with the outer case a, the flanged and suspended air cell f
containing mercury in its bottom and having gas holes o in its flange, and the
rising and falling cylinder h having a close top and flange valve overhanging the
gas holes o and having its lower end sealed in the mercury as shown and
described.
5th The combination of case a having an enlarged screw threaded upper section e,
the screw threaded cap c with tip socket, tip d, the flanged air cell f having
perforated sustaining flange i, the rising and falling air cylinder h having flange
valve at the top, and the mercury seal at the bottom, substantially as shown and
described.
6th The combination with the enclosing shell a, c, and the air cell f, of the rising
and falling air cylinder h having a gas valve attached thereto, and the valve k, and
valve stem provided with spring land nut or holding bar m as and for the purpose
described.
7th The combination with case a having an enlarged shoulder section e, of the
air cell f having flange i with gas holes o, and the regulator or adjusting ring i
having similar holes laid between the flange of the air cell and the shoulder of the
case and made axially adjustable to increase or diminish the flow of gas at will,
substantially as described.
8th The combination with the gas burner having a pneumatic cut off, of the
tube n² and conduit n, the stem having valve r at one end and push button 8 at
the other end and the coiled spring surrounding said stem substantially as and for
the purpose described.