Improvements in Sewer Manhole or Surface Box Covers.
Year: 1894

page_text: Date of Application, 10th Nov., 1894
Complete Specification Left. 10th Sept., 1895-Accepted, 19th Oct., 1895
PROVISIONAL SPECIFICATION.
Improvements in Sewer Manhole or Surface Box Covers.
We, EDWIN JAMES PRESTON of the Firm of J. Stone & Co. of Deptford in
the County of Kent and DUNCAN WILLIAM MCLAREN in the employ of the
said firm, Engineers do hereby declare the nature of this invention to be as
follows:-
-:
These improvements have for their object to render sewer manhole or surface
box covers ventilating or nonventilating at will and in a simple and convenient
manner. For this purpose the circular rectangular or other frame is provided
with a cover having usual slots or openings through about one half of its surface
while the other half is made without such slots. In the inner lower half part of
the frame below the slotted part of the cover we provide a ledge upon which rests
loosely a diaphragm plate having on one side an upright partition which is as high
as the distance up to the cover and upon the other side an upright partition the
height of which comes somewhat short of such distance. When the plate is
placed with the high partition uppermost ventilation is cut off by the said
partition a closed chamber being formed under the slotted part of the cover but
when the plate is placed in a reverse position that is with the shallow partition
uppermost draught or ventilation is afforded by the space left between the top of
the said partition and the bottom of the cover; the tray thus formed also forming
a dirt box to prevent mud and road detritus from falling into the manhole or
sewer.
Dated this 10th day of November 1894.
JENSEN & SON,
77 Chancery Lane, London, W.C., Patent Agents.
We, EDWIN JAMES PRESTON of the Firm of J. Stone & Co. of Deptford in
the County of Kent and DUNCAN WILLIAM MCLAREN in the employ of the
said firm Engineers 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
manner.
-
These improvements have for their object to render sewer manhole or surface
box covers ventilating or nonventilating at will and in a simple and convenient
For this purpose the circular rectangular or other frame is provided
with a cover having usual slots or openings through about one half or more of its
surface while the other half is made without such slots. In the inner lower half part
of the frame below the slotted part of the cover we provide a ledge upon which
rests loosely a diaphragm plate having on one side an upright partition which is as
high as the distance up to the cover and upon the other side an upright partition
the height of which comes somewhat short of such distance. When the plate is
placed with the high partition uppermost, ventilation is cut off by the said

page_text: &
partition, a closed chamber being formed under the slotted part of the cover, but
when the plate is placed in a reverse position that is with the shallow partition
uppermost, draught or ventilation is afforded by the space left between the top of
the said partition and the bottom of the cover; the tray thus formed also forming
dirt box to prevent sand and road detritus from falling into the manhole or sewer.
Fig. 1 of the accompanying drawings is a plan view of a rectangular sewer
manhole, Fig. 2 a plan view of a round sewer manhole and Figs. 3 and 4 vertical
cross sectional views shewing the manhole arranged as ventilating and non-
ventilating respectively. The frame A is provided with a cover B having the
usual slots B¹ through about one half of its surface. A' is a ledge upon which
rests loosely a diaphragm plate C having on one side an upright partition C¹ which
is as high as the distance up to the cover B and upon the other side an upright
partition C the height of which comes somewhat short of such distance. When
the plate C is placed as in Fig. 3 with the high partition C₁ uppermost, the
ventilation is cut off, but when the plate C is placed as in Fig. 4 with the low
partition C2 uppermost, ventilation is afforded by the space D above said partition.
The tray formed by the plate C forms a dirt box to prevent sand and road detritus
from falling into the manhole or sewer. A rubber strip F inserted in a groove in
the cover B ensures a tight joint between the latter and the partition C¹.
Fig. 5 is a vertical cross section shewing the application of a light flap valve E
such as described in the Specification of Chadwick and Preston's Patent No. 4530
of 1894 to this invention; this valve seats itself against the rim of the open
partition C¹ and admits of fresh air flowing into the sewer but prevents egress of
foul air therefrom. The valve is fastened to a wrought iron frame E' which drops
easily into slots formed in the casting.
It rests with its legs C*
reverse position with the
making joint with the
The ledge A¹ is made
Fig. 6 is a vertical section and Fig. 7 a plan section of a manhole cover in
which the tray or dirt box C is similarly made reversible.
in the normal position shewn on the ledge A', or in the
legs C on the said ledge, the rubber ring F in that case
underside of the unperforated outer part of the cover B.
with slots A for the legs to pass freely through.
Having now particularly described and ascertained the said invention and in
what manner the same is to be performed, we declare that what we claim is :-
1. The application and use in manhole or surface box covers of a cover with
lots in one portion of same and of a loose reversible tray resting on a ledge on
the frame, said tray in one position making joint with the unperforated portion of
the cover thus preventing escape of gas from the sewer, and in the reverse position
permitting ventilation, substantially as set forth.
2. The construction of manhole or surface box cover shewn in Figures 1 to 4.
3. The application and use in manhole or surface box covers of the character
described of a light flap valve such as E to the partition C¹ of the tray C Figs. 1
to 4 for the purpose of permitting entry of air into the sewer but not exit of sewer
gas when the partition C' is in the up position substantially as described with
reference to Fig. 5.
4. The construction of manhole or surface box cover shewn in Figs. 6 and 7.
Dated this 10th day of September 1895.
JENSEN & SON,
77 Chancery Lane, London, W.C.