IMPROVEMENTS IN THE METHOD OF AND APPARATUS FOR LETTING ON AND CUTTING OFF THE SUPPLY OF GAS TO GROUPS OR DISTRICTS OF STREET.AND OTHER LAMPS FROM A CENTRAL POINT OR DEPOT
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Daniel Fryer and William James
Williams at the Office of the Commissioners of Patents, with their
Petition, on the 10th April 1862.
We, DANIEL FRYER, of Carlton.Square;. Old. Kent Road, County of Surrey,
and WILLIAM JAMES WILLIAMS, of: Arundel Street, Strand, London, County of
Middlesex, Gentleman, do hereby declare the, nature of the said Invention
for "IMPROVEMENTS IN THE METHOD OF AND APPARATUS FOR LETTING ON AND
CUTTING OFF THE SUPPLY OF GAS TO GROUPS OR DISTRICTS OF STREET.AND OTHER
LAMPS FROM A CENTRAL POINT OR DEPOT," to be as follows:-
We would premise that our plan of letting on and cutting off the supply of
gas from street lamps is applicable in whatever way the lighting of the lamps
is effected, whether by hand or by mechanical or chemical arrangements, or
by means of the electric spark, as one of the leading features of our Invention
gives, however, a method of simultaneously extinguishing a whole series of
lamps by means of an almost instantaneous cutting off of the supply of gas, and
as almost instantaneous the letting on of the gas is by the same apparatus
effected. We should prefer the arrangement of lighting by means of an
electric spark passed along a wire to each lamp. We are aware, however, that
such has been previously applied, hence we do not claim this method of
lighting except when used in connexion with our Invention for letting on and
cutting off the supply of gas to the lamps. Our plan, then, consists in applying
to the ordinary branch gas tube which supplies each lamp, a flexible air-tight
junction of india-rubber, or such like material, that is to say, the gas tube

page_text: may be severed, and a piece removed anywhere near the lamp post, and the
severed ends joined with a piece of flexible tube having air-tight joints. On
each side of the tube may be placed two small plates to act as nippers, so that
if they be compressed by any force they will nip the flexible tube and close
the passage, we now enclose this flexible portion in an air-tight flexible
chamber formed of materials capable of allowing it to collapse and expand
without fracture when the air is withdrawn or forced into it. With this
arrangement it will be seen, that if the air by any means be extracted from
the air-tight flexible chamber, it will collapse, and the external pressure
will cause the nippers to grasp the flexible tube, and close its passage, and
cut off the supply of any gas passing through to the lamp, and upon the
equilibrium being restored by the admission of air, the current of gas will be
let on, the nippers relaxing their grasp from this relaxed pressure. If, on the
other hand, the air be forced into the chamber, the increased pressure will act
in a similar manner.
In order to exhaust or force in air to these flexible air-tight chambers, we
adopt the following arrangement:-Starting from each central point or depôt,
an air-tight pipe passes to each group or district of lamps, and from this tube
an air-tight junction tube proceeds to the flexible chamber attached to the
supply pipe of each lamp, and terminates in an open end in the said air-tight
chamber; the ends of all the main or district pipes are collected or terminate
in an air-tight tank or chamber, to which is attached a large air-pump or air-
exhausting machine. By means of the pump or machine, it will be seen that
the air may be withdrawn or forced into the flexible chamber at each lamp,
and the gas either cut off or let on at pleasure, and almost instantaneously.