Improvements in Fresh Air Inlet Sewer Manhole and Lamphole Covers and Frames.
Year: 1899

page_text: Date of Application, 22nd Apr., 1899
Complete Specification Left, 22nd Jan., 1900-Accepted, 10th Mar., 1900
PROVISIONAL SPECIFICATION.
Improvements in Fresh Air Inlet Sewer Manhole and Lamphole
Covers and Frames.
I, FREDERICK THOMAS GRANT, of Maidstone, in the County of Kent, Assistant
Borough Surveyor, do hereby declare the nature of this invention to be as
follows:-
The improvements relate to the cover and cover frame or flange of sewer man-
holes or lampholes and they consist in supplying the cover with one or more
recesses or passage ways made in the side and preferably underneath part of
the same through which air may pass, also in furnishing the frame with one or
more passage ways which when the cover is fixed in or on the frame shall corre-
spond with the passage ways in the cover and so form a continuous passage or
passages. At the end of the passage way, in the frame is placed an air inlet
valve which allows the fresh air which enters through the grating and passage
ways in cover and frame to pass down and entering the well of the sewer.
Dated this 22nd day of April 1899.
HERBERT HADDAN & Co.,
Agents to Applicant.
Improvements in Fresh Air Inlet Sewer Manhole and Lamphole
Covers and Frames.
I, FREDERICK THOMAS GRANT, of Maidstone, in the. County of Kent, Assistant
Borough Surveyor, 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:-
These improvements relate to the cover and cover frame or flange of sewer
manholes or lamp holes and they consist in providing the cover with one or more
recesses or passage ways made in the side and preferably underneath part of the
same, through which passage ways air may pass, also in providing the flame
with one or more passage ways which when the cover is fixed in or on the frame
shall correspond with the passage ways in the cover and so form a continuous
passage or passages for air to pass through. At the end of the passage way in
the frame is placed an air inlet valve which allows of the fresh air passing through
the grating and passage ways in cover and frame to pass down and enter the well
of the sewer.
Fig. 1 is a sectional elevation Fig. 2 a half plan and half horizontal section

page_text: through a fresh air inlet sewer manhole cover and frame constructed according
to my invention. Figure 3 is sectional elevation of a modification and Figure 4
is a plan of a cover to be used when the dirt box is removed.
Referring more particularly to Figures 1 and 2 A is the frame or flange of a
sewer manhole and B the cover for same. The cover is formed as an example
with four lateral recesses holes or passages C in the underneath part B₁ for allow-
ing air to pass down through the same, and the frame A is formed with four
passages A which correspond with the passages C in the cover.
In each passage
is provided an air inlet valve D made of thin sheet aluminium or other suitable
light material; it is mounted in wire hinge loops D₁ as shown or so as to work
quite freely. These hinges D' are preferably mounted on a small frame or seat-
ing E which is truly faced so as to form a proper seating for the valve and this
seating is either fixed over or in the opening or recess A¹ in the frame or as shewn
to a separate small frame F adapted to fit into the said opening. In practice
I have found it convenient to provide a small separate frame F for each valve
with a groove on three sides and similarly to have a corresponding groove round
the three sides of the recesses A¹ in the frame. These grooves are all more or
less made dovetail in section. It is then possible to make the whole of the
frame A of cast iron without any machinery whatever. The small frames F are
also cast and truly faced, if required, on one side but this is not absolutely
necessary. The seatings E with the valves D thereon are screwed or otherwise
fastened to the small frames F which are dropped into the recesses in the frame A
while turned upside down. Molten lead is then poured in at G and H, Figure 2,
and fills the groove which is indicated by the dotted lines in Figure 1 and com-
pletely binds the whole together without its being necessary to use any other
kind of fastening. It is however apparent that I do not limit myself to this par-
ticular form of fastening or attachment of the parts, but I describe it because it
is a simple, efficient and cheap method. The usually required dirt box is in
this case suspended from the frame A as shewn at I, Figure 1, by its flange I¹
resting on the lower flange of the frame in which box all dirt falling through
the holes in the cover is collected and the box is provided with a handle consisting
of a rod K the ends of which pass through the sides of the box and are rivetted
thereto or any other suitable construction of handle may be employed. If the
manhole or entrance thereto be round in section the valves are placed over chases
in the brick work as shewn or the valves may be arranged opposite to the angles
of the manhole if its entrance be square. The cover is provided with a lug or
projection B which takes into a corresponding recess in the upper part of the
frame A, see Figure 2. By this means it will be impossible to properly close
the cover unless the passages C therein register with the valves D in the frame A.
When the pressure of the atmosphere is slightly greater than the pressure of
the gas in the sewer the valves will open and fresh air will pass through them
down into the sewer well in the direction indicated by the arrows, but if the sewer
gas is of greater pressure than that of the atmosphere the valves will close.
Referring to Figures 3 and 4 it will be seen that the construction is very
similar to that just described and shewn in Figures 1 and 2, the only practical
difference being that the cover is not provided with a lower part or extension 131
having passages, holes or recesses C. It is consequently immaterial how the
cover is put on so long as it is properly down in the frame and flush with the top
thereof. When the dirt box is removed for emptying or any other purpose it
may be replaced by an empty one or as shewn by a cover L with handle L which
prevents the escape of sewer gas or impure air from the grating meanwhile.
also naturally applies to the construction first described.
This
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. A sewer manhole or lamphole frame provided with
n carer having holes

page_text: for the admission of air, one or more transverse passage ways in the frame, a
light freely working valve or valves hung in such a manner as to permit of the
ingress of fresh air when the pressure of the atmosphere exceeds that in the sewer
but to close in the case of sewer gas over pressure and means such as a dirt box
for preventing the ingress of dirt to the sewer and the escape of gas substantially
as set forth.
2. A sewer manhole or lamphole frame A having a passage or passages A¹, a
small frame or frames F to fit in said passages or to be attached to the frame A
a light freely working valve or valves D and means for preventing the ingress
of dirt to the sewer and the escape of gas or foul air therefrom substantially as
described and shewn.
3. The constructions of sewer manhole frame and cover described with refer-
ence to the drawing.
.