Improvements in or relating to the Covers of Man-hole and similar Openings.
Year: 1889

page_text: Date of Application, 18th Oct., 1889-Accepted, 23rd Nov., 1889
COMPLETE SPECIFICATION.
Improvements in or relating to the Covers of Man-hole and similar
Openings.
I, JOHN JONES, of 40 Sydney Street, Chelsea, London, S.W., Builder, 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 relates to the covers of man-hole and similar openings and more
especially those through which access is bad to drains and has for its object to so
construct them that the liquid resulting from the condensation of the vapours by
contact with the said covers will automatically form a water seal and prevent the
escape of the gases around the cover.
In the accompanying drawing I have represented in section one way of carrying
out this invention the apparatus there shown consisting of the following parts :-
A frame A which may preferably be of cast iron and in plan is of square, oblong,
circular or other desired form. This frame A is formed with an inwardly and
upwardly extending lip A' between which and the frame proper is formed a channel A
to contain the liquid X to form the seal, the lip A¹ extending upwards to a height
such as will admit of a sufficient quantity of liquid being contained in the channel A'
to form an effective gas-tight seal. B is a plate domed in any such manner or form
as will cause the liquid condensed by contact with its under surface to trickle along
the underside and towards the edges of the said plate down into the channel A.
This plate is preferably of iron or other cold material to facilitate condensation and
is advantageously provided with projections or handles B₁ by means of which it may
be raised when necessary. C is a covering plate which rests in preferably inclined
rabbets A³ formed in the upper edge of the frame A and in which plate are provided
openings for the insertion of lifting keys or for the pouring in of water for
initially sealing the cover or to replace the water when through excessive heat it
may have evaporated or in other way become removed, the upper curved or inclined
surface of the plate B directing the water so introduced straight to the channel A².
The covering plate C may rest on the upper part of the domed plate B in the
manner shown in the drawing, or it may be rivetted or otherwise secured to it or it
may be formed as an integral part of the plate B or it might be quite separate from
the plate B or the plate C might be dispensed with entirely.
The plate B to the dome of which as before explained may be given any desired
curve or incline may be grooved or corrugated at its underside so as to facilitate the
movement of the liquid from the plate B to the channel A².
The frame A may be built or cemented into a roadway or wherever required in
any convenient manner, the horizontal flange A preferably roughened underneath
to facilitate the adhesion of the cement or concrete serving to give the frame a firm
anchorage.
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 ;-
1. In a man-hole or similar cover the utilization of the liquid formed by con-
densation on the manhole cover for automatically making a gas tight seal around its
edges substantially as herein described and illustrated in the accompanying
drawing

page_text: 2. In a manhole or similar cover the combination with a frame A provided with
a channel such as A2 of a domed or similar plate such as B the edges of which rest
in or enter the said channel substantially as and for the purpose herein described and
illustrated in the accompanying drawing.
Dated this 18th day of October 1889.
JOHN JONES.
W. P. Thompson & Boult,
Agents for the Applicant.