IMPROVEMENTS IN APPA- RATUS FOR LIGHTING AND EXTINGUISHING PUBLIC AND OTHER GAS LAMPS OR LIGHTS
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by Alexander Fairlie Wilson at the
Office of the Commissioners of Patents, with his Petition, on the
22nd August 1878.
I, ALEXANDER FAIRLIE WILSON, Gas and Consulting Engineer, of 18,
Buckingham Street, Adelphi, in the County of Middlesex, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN APPA-
RATUS FOR LIGHTING AND EXTINGUISHING PUBLIC AND OTHER GAS LAMPS OR
LIGHTS," to be as follows:-
This Invention relates to the lighting and extinguishing of public or
other gas lamps or lights automatically, the actuating power being the
pressure of the gas itself, and is based upon an Invention for which
Letters Patent, No. 2101, dated July 12th 1872, were granted.
The general arrangement of the apparatus is very similar to that
described in the Specification of the Invention referred to, and consists
of a circular and covered chamber or small tank partially filled with
mercury, and with an inlet pipe for the gas passing through its centre
and rising within to some distance above the bottom. Near the circum-
ference and on opposite sides of the bottom of the tank are introduced

page_text: ascending will allow the mercury to flow back again to the tank until
the float is nearly empty.
•
The reason for attaching a float such as I have described is to obtain
à support or sustaining medium for the holder in its descent, corre-
sponding to the air space which must be immersed under the level of the
mercury before the float would begin to fill, and a weight on its ascent
to the extent of the height to which the float has to be raised above the
level of the mercury, before the friction of the tubes will allow the
syphon to act.
'
The object of appling the float to the gas holder is to obtain a range
betwixt the mixamum pressure at which the gas-would light, and the
minimum at which the light would be extinguished, so that when once
the lamps are lighted they will not become extinguished until the pres-
sure is withdrawn to the minimum, and when extinguished will not
relight until the pressure is again increased to the maximum.
The float is also capable of adjustment by suspending it at various
heights to suit the maximum and minimum pressure, at which it is
desirable that the lamps should be lighted and extinguished.
A modification of this float may be employed by turning it bottom
upwards and dispensing with the syphons, when it will act by a
mechanical movement on the centre pins and allow the greater portion
of the air to escape in the descent, but on its ascent it will form a weight
by its tendency to create a vacuum, which will cause the float to carry
up a portion of the mercury above the level of the rest:
i
One or more valves cither hydraulic or with a ground or soft surface
seat would assist this action by more effectually expelling the air.
Under some circumstances this modification may be found convenient,
but the first-named arrangement is preferred.
Another improvement consists in forming concentric rings or cups on
the exterior of the holder, so as to allow of its weight being regulated by
shot or sand which is confined thereto by being covered with a suitable
plate. At or near the top the tank is furnished with levelling points,
and the bottom in order to adjust it at a level is provided with lugs and
screws, which bear on a plate resting loose on the top of the lamp
column.

page_text: It is also proposed in carrying out this Invention to make the pipes
connecting the burners to the tank of a bent or curved form in pre-
ference to right angled junctions.
;
Although the foregoing describes the apparatus as placed on the top
of the column, I reserve to myself the right to place the principle part
of the apparatus within the column at its base, or in any other situation
found most convenient or advantageous.
The action of the apparatus is as follows:-The exterior chamber
being connected to the service pipe, gas is admitted to the interior
through the inlet pipe, the gas passing from thence through the small
orifice in the partition to the jet burner, where it is lighted and kept
continuously burning. When it is desired to light up the ordinary
burners, extra pressure is put on at the gas works, the consequence is
that the gas holder herein described rises and unseals the partition
enclosing the outlet channel to the ordinary burner and allows the gas:
to pass freely to the lamp burner, and as the flame of the jet burner is
increased by the augmented pressure it readily sets light to the gas
issuing from the ordinary burner. The pressure at the work is then
reduced when the gas holder will remain suspended by the buoyancy of
the float, until the pressure is reduced sufficiently to immerse the float
and seal the outlet to the ordinary burner, when the light will be
extinguished.