Air Inlet, Gully Trap, and Man-hole Cover for Drains.
Year: 1889

page_text: Date of Application, 29th Apr., 1889
Complete Specification Left, 13th Dec., 1889-Accepted, 15th Mar.. 1890
PROVISIONAL SPECIFICATION.
Fresh Air Inlet, Gully Trap, and Man-hole Cover for Drains.
CHARLES WILLIAM MILLAR 8 Wellington Road Saint Johns Wood London
Surveyor do hereby declare the nature of this invention to be as follows:-
An Air-tight Man-hole cover provided with a central opening protected by a grating,
under which is a Gully trap of ordinary construction, but having in one side a Fresh
Air Inlet with valve, this valve which is formed of mica, lignite, vulcanite, hard wood
or metal is acted upon by the pressure of the fresh air being drawn through the
grating by the suction of the ventilating shaft of the drain hut immediately the
current ceases the valve falls, closing the aperture, the presence of foul gas or air in
the manhole causes pressure on the valve preventing any portion of it escaping. The
aperture may be made with one or more valves. The body of the Trap may be made
of iron lead earthenware or any other material such as is generally used for making
such things. The Manhole Cover & Frame are imbedded in stone or composition are
formed of iron or other metal. The cover is fitted with small inclined flanges corre-
sponding with others on the frame and when forced into position and the locks shot
the cover is hermetically closed.
CHAS. W. MILLAR.
COMPLETE SPECIFICATION.
Fresh Air Inlet, Gully Trap, and Man-hole Cover for Drains.
CHARLES WILLIAM MILLAR 8, Wellington Road St. Johns Wood London Surveyor
(Fellow of the Surveyors Institute) 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 :-
Referring to Sheet 1. An iron manhole cover A in form either circular, oblong, or
otherwise in the case of a circular cover, arranged for the purpose of compression on
to its bed is fitted with inclined flanges corresponding with others, in an inverse plane
on the frame which being brought together by giving the cover a slight circular
motion causes the lid to he hermetically pressed into its bed. The cover is then
locked by dropping hinged tongues A¹ fitted at either side of the frame into corre-
sponding slots in the cover the cover is removed by reversing this operation. In
other shaped covers ordinary fastenings would be used the cover and frame can be
bedded in the brickwork of the manhole E but it is preferred that it should be bedded
in stone or composition stone this being bedded on the brickwork of the manhole.
In the moveable cover is a central opening A² provided with an open work grating
for the purpose of preventing any large substance passing through under which is a
chamber B attached to the moveable cover by means of a flange B₁ with bolts & nuts
making it easy of removal, the diameter of this chamber is slightly larger than the
central opening of the cover and it may be any depth that is suitable to the depth
of manhole the lowest part of this chamber is formed in the shape of a letter S or
what is known as a simple syphon C and when the depth of the chamber is not too
great is formed in one piece; but if required to be any considerable depth it would
be formed in a separate piece but it is not considered desirable unless in very excep-
tional cases to deepen the chamber to a greater extent than two or three inches below
the underside of the side outlet bereinafter described.
The chamber is fitted at the side at any depth below the grating in the cover that
may be desired with an opening which forms the inlet D for fresh air to the manhole E
this inlet is formed of such a size as will admit a sufficient volume of fresh air to

page_text: supply the system of drainage and ventilation to be dealt with & it is provided with a
valve D' carefully suspended at an angle causing it normally to lie on its bed, which
is acted upon by the pressure of the foul air & gases in the drain and man hole causing
it to press close on its bed, until the current being changed by the suction of the
ventilating shaft, the inward pressure of fresh air causes to it open (inwards) the
fresh air passing freely into the man hole, is drawn into the drain F and thence through
the entire system escaping by the ventilating shaft or shafts carrying all foul air and
gases with it.
The manhole cover locks and frame are formed of cast iron, wrought iron, s'eel
brass or copper. The grating is formed of either of the aforesaid metals or it may
be made in earthenware or stoneware. The chamber with its extension and opening
are made of cast or wrought iron, steel brass, copper, tin, zinc, lead or a combination
of any
of these metals or of china earthenware stoneware or glass. The valve in the
inlet is formed of mica lignite, vulcanite, hardwood, tin, zinc, iron, brass, copper,
silver or glass.
Referring to Sheet 2 the Drawing represents the application of the fresh air inlet
to an ordinary street gulley B with the inlet valve A placed at the side, the syphon C.
seals the gulley against pressure of gas from the sewers while the valve A admits
fresh air but closes immediately any air or gas moves towards it from the sewer D by
means of the pipe E connecting the gulley to sewer by this means the sewers can be
supplied with an unlimited amount of fresh air without the fear of the sewer gas
escaping into the streets.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed I declare that what I
claim is
1st. Simplification of the means of supplying fresh air to drains and sewers at the
same time preventing a back rush of foul air or sewer gas by the means described in
the Specification.
2nd. Acceleration of the volume of fresh air to the drains or sewer by the same
means.
3rd. Economy combined with greater efficiency in the arrangements of several of
the most important parts of a properly constructed sanitary system.
4th. The application of the inlet and valve to the side or front of a street gulley
for the purpose of supplying fresh air to the sewers without allowing the pressure
caused by the ebb & flow or increase of the flow to force the foul air & gases up through
the gulleys.
Dated this Thirteenth day of December 1889.
ITT AS WI MILLAR