IMPROVEMENTS IN OR APPLICABLE TO THE VALVES OF GAS MAINS OR PIPES FOR THE PURPOSE OF MAINTAINING A TIGHT JOINT
Year: 1880

page_text: LETTERS PATENT to John Aird, of Belvedere Road, Lambeth, in the County
of Surrey, Contractor, for an Invention of "IMPROVEMENTS IN OR APPLICABLE
TO THE VALVES OF GAS MAINS OR PIPES FOR THE PURPOSE OF MAINTAINING
A TIGHT JOINT."
PROVISIONAL SPECIFICATION left by the said John Aird at the Office
of the Commissioners of Patents on the 8th July 1880.
JOHN AIRD, of Belvedere Road, Lambeth, in the County of Surrey, Contractor.
"IMPROVEMENTS IN OR APPLICABLE TO THE VALVES OF GAS MAINS OR PIPES FOR
THE PURPOSE OF MAINTAINING A TIGHT JOINT."
My Invention relates to the valvular apparatus of gas mains or pipes, and bas
for its object maintaining a tight joint so as to effectually prevent accidental
escape of gas and the consequent liability of explosion.
In carrying out my Invention in order to effect this object I employ in the gas
main or pipe two valves arranged at a suitable distance apart, so as to form
between them a space or chamber, into which I introduce water or other suitable
liquid, thereby forming a hermetic or liquid sealed joint. The two valves may be
arranged so as to be capable of being operated simultaneously or otherwise from
the exterior by any usual or suitable means.
If desired an additional liquid chamber or chambers may be employed with the
requisite number of valves operated as before mentioned.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Aird in the Great Seal Patent Office on the 5th January
1881.
JOHN AIRD, of Belvedere Road, Lambeth, in the County of Surrey, Contractor.
"IMPROVEMENTS IN OR APPLICABLE TO THE VALVES OF GAS MAINS OR PIPES FOR
THE PURPOSE OF MAINTAINING A TIGHT JOINT."
My said Invention relates to the valvular apparatus of gas mains or pipes, and
has for its object maintaining a tight joint so as to effectually prevent accidental
escape of gas-and-the-consequent liability of explosion.
In carrying out my said Invention in order to effect this object. Lemploy in the
gas main or pipe two valves arranged at a suitable distance apart, so as to form
between them a space or chamber, into which I introduce water or other suitable
liquid, thereby forming a hermetic or liquid scaled joint. The two valves may be
arranged so as to be capable of being operated simultaneously or otherwise from
the exterior by any usual or suitable means.
And in order that my said Invention may be fully understood, I shall now
proceed more particularly to describe the saine, and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Drawings represents a longitudinal section of a
portion of a gas main-or-pipe having adapted thereto valvular apparatus constructed
and arranged in accordance with my said Invention, Figure-2-is-a sectional
elevation, the section being taken at right angles to Figure 1, and Figure 3 is a
horizontal section of the same.
In carrying out my said Invention I attach to the gas main or pipe A (at the
point at which it is desired to provide a division or partition in the main or pipe)
a valve box B having guides at a, a, in which are fitted two valves C, C, so as to
be capable of vertical motion in the said guides. The two valves are arranged at
a convenient distance apart, and when in their lowest position, as shewn in the
Drawing, they form a liquid tight chamber D, into which I introduce water or
other suitable liquid, thereby obtaining a hermetic or liquid sealed joint. The
two valves are operated simultaneously by means of a worm b engaging with rack
teeth formed on the back or inner face of both valves, the said pinion being carried
on a spindle c, which passes through a stuffing box in the cover d of the valve box,
and is suitably shaped at its extremity for the reception of a handle or other
appliance, by the aid of which the spindle may be operated. Assuming the valves
to be in the position shewn in the Drawing, by the act of operating the spindle c
in a suitable direction the valves are raised, and the water escaping along the main
or pipe to the nearest syphon the main or pipe is open for the passage of the gas.
When again it is required to close the main or pipe the spindle c is turned in a
direction the reverse of that of its previous motion, and the valves are lowered
into the position shown in the Drawing; the chamber D is then filled with water
as before, thus effectually sealing the main against any leakago of gas through the
valves.
Tho valves when in their lowest position are securely pressed against their
respective faces in the valve box by the thrust of the worin b forcing the backs or
inuer faces of the valves against the inclined planes at f, f, of two snugs g, g,
formed on the valve box.
The water is supplied to the chamber D through an inlet h either by hand or
from a neighbouring water main or service cistern. A gauge i is fitted to the valve
box for the purpose of indicating the level of the water, which should remain constant
if the valves are working properly. An attendant may therefore ascertain at

page_text: any time by an inspection of the guage whether or not the valves are acting
properly.
The water inlet h and guage i are protected by a cover k.
If desired an additional liquid chamber or chambers D may be employed with
the requisite number of valves operated as before mentioned.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original,
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent, is,-
The employment in gas mains or pipes of two or more valves in combination
with a body of liquid interposed between them for the purpose of maintaining a
gas tight joint, substantially as hereinbefore described.
In witness whereof, I, the said John Aird, have to this my Specification
set my hand and seal, this Twentieth day of December, One thousand
eight hundred and eighty.