An Improved Trap and Check Valve for Preventing the Escape of Sewer Gas and Storm Waters at Sewer Gullies and other Places.
Year: 1893

page_text: Date of Application, 7th Dec., 1893
Complete Specification Left, 6th Sept., 1894-Accepted, 20th Oct., 1894
PROVISIONAL SPECIFICATION.
An Improved Trap and Check Valve for Preventing the Escape
of Sewer Gas and Storm Waters at Sewer Gullies and other
Places.
I, JAMES KING of White Horse Yard, Lower North Street, Poplar,
London, E., Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention consists of a combined syphon and non-return check valve,
principally designed for street gullies (but applicable also in other situations) for
preventing the escape of sewer gas at all times, and the overflow of storm waters in
low-lying districts in the event of the sewer becoming stopped or overcharged with
water from a higher level.
The syphon is preferably in the form of a bell-trap, the only admission to the
bell being through valves working in valve boxes or chambers projecting from the
sides of the bell near the lower part, the valves being pivoted flap valves closing
by gravity against scats in the lower sides of the valve boxes.
The bell may be in the form of a cylinder of considerable height standing in the
gully or other chamber, the outlet pipe from which to the sewer rises within the
bell nearly to the closed upper end thereof, so that the trap is sealed by a con-
siderable depth of water in the gully chamber, in which the valves are at all times
submerged.
The valves open easily by the flow of water to the outlet, but close by gravity
against its return, any back pressure, either of water or sewer gas, only tending
to close them more tightly against their seats so that the trap is equally efficient in
wet or dry weather, even should the water-seal in the trap dry away.
Dated this 7th dor of December 1802
J. KING,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
An Improved Trap and Check Valve for Preventing the Escape
of Sewer Gas and Storm Waters at Sewer Gullies and other
Places.
I, JAMES KING, of White Horse Yard, Lower North Street, Poplar,
London, E. Engineer, 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 consists of a combined syphon trap and non-return check valve,
principally designed for street gullies (but applicable also in other situations) for
preventing the escape of sewer gas, and when applied in low-lying districts for
preventing the overflow of storm waters in the event of the sewer becoming
overcharged with water from a higher level.
The invention is illustrated in the drawings accompanying, and forming part of,
this Specification, wherein Figure 1 represents a vertical section of the syphon
trap and check valve, as arranged within a street gulley, and Figure 2 shews an
elevation of the same separately.

page_text: The siphon or bell trap is formed of a hood or bell A of cylindrical form
having valve boxes B which project at two opposite sides near the lower part, the
hood or bell enclosing the outlet pipe C which rises therein nearly to the top.
The valve boxes are open to the interior of the hood and have apertures in their
inclined lower sides which are the only inlets to the bell or hood and which are
normally closed by flap valves D hung on pivots d opening inwards and upwards
and closing by gravity against seats upon the lower sides of the valve boxes B.
The mouth of the hood or bell A is bolted down upon a base plate E cast in one
with the outlet pipe C. The top A' of the hood. is a hinged lid secured by an
eyebolt and fly-nut to give access to the interior for the removal of obstruction
when required. The outlet pipe C is open at top and communicates with the drain
leading to the sewer and its mouth is provided with an intercepting grating or
basket c in the form of a perforated cone bolted by its flange to the mouth of the
pipe, the smaller end of the conc projecting downwards within the pipe C so that
in the event of any large obstruction being forced by back pressure up the pipe C
it will be intercepted and prevented from passing over into the hood A. Around
the foundation on which the outlet trap is erected is formed a sump F for the
deposit of mud in the gulley chamber G. The water level both inside and outside
the hood or bell is normally above the apertures b, so that a hydraulic scal is
constantly maintained, the lower sides of the valve boxes in which said apertures
are formed being inclined so that the valves D open casily, as indicated by the
dotted lines, under the flow of water from the gulley to the outlet C but close by
gravity against its return, any back pressure, either of water or of sewer gas, only
tending to close them more tightly against their seats, so that no return of water
can occur through the valves and the trap will be efficient, even should the
hydraulic seal fail in time of drought. The valve seats, and likewise the flange
upon which the lid A' closes, may be faced or packed with leather or other suitable
material, to ensure a tight joint.
In operation, the siphon becomes primed when the water rises in the gulley to
about the height of the top of the hood A and the water continues to be carried off
through the outlet C until the water level falls to the top of apertures b whereupon
the siphon action ceases and the trap remains sealed but inoperative until a further
accession of water occurs.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
The herein described combined siphon trap and check valves for gullies and the
like, consisting of a hood or casing enclosing the outlet pipe and provided with
laterally-projecting valve-boxes containing flap valves opening inwardly and closing
by gravity on apertures in the inclined lower sides of the valve boxes substantially
as specified, the valves being normally sealed by immersion in the water within the
gulley chamber, as described.
Dated September 6th 1894
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.