Improvements in Sealing Doors or Man-holes against Escape of Air and Gas.
Year: 1885

page_text: Improvements in Sealing Doors or Man-holes against Escape of
Air and Gas.
I, ANDREW AINSLIE COMMON, of N° 63 Eaton Rise Ealing in the County of
Middlesex, Engineer do hereby declare the nature of my invention for "IMPROVE-
"
MENTS IN SEALING DOORS OR MAN-HOLES AGAINST ESCAPE OF AIR AND GAS to
be as follows:-
My Invention relates to horizontal inspection doors or man-holes for sewers or
for any place where it is desired to prevent escape of air or gas while preserving
every facility of opening and closing.
I propose to use a movable plate or door preferably of a circular form which
I provide with a flanged lip fitting when the door is closed into a corresponding
groove or recess which I make in the frame fixed permanently in position.
I propose to place in the aforesaid groove or recess a sufficient quantity of
Mercury to make an air tight joint and to protect the grooves from the entrance
of any foreign matter when the door is opened.
I may introduce into the groove a ring or plug, which will lie beneath the flange
of the door when this latter is closed but which upon its removal will float at once
to the top of the mercury and close the groove.
By using mercury in the groove I always maintain an air tight closing with
great facility of inspection it being only necessary to lift off and replace the door
after inspection in lieu of breaking and making the ordinary mechanical or cement
joint.

page_text: COMPLETE SPECIFICATION.
Improvements in Sealing Doors or Man-holes against Escape of
Air and Gas.
I ANDREW AINSLIE COMMON, of N° 63 Eaton Rise, Ealing in the County of
Middlesex, Engineer, do hereby declare the nature of my invention for IMPROVE-
MENTS IN SEALING DOORS OR MAN-HOLES AGAINST ESCAPE OF AIR AND GAS and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
My invention relates to horizontal inspection doors or man-holes for sewers or
for any place where it is desired to prevent escape of air or gas while preserving
every facility of opening and closing.
I use a movable plate or door, preferably of a circular form, which I provide
with a flanged lip, fitting when the door is closed into a corresponding groove or
recess which I make in the frame fixed permanently in position.
I place in the aforesaid groove or recess a sufficient quantity of Mercury to
make an air tight metallic joint; and to protect the groove from the entrance of
any foreign matter when the door is opened, I may introduce into the groove a
ring or plug of any suitable shape or material, which will lie beneath the flange of
the door when this latter is closed, but which upon its removal will float at once
to the top of the Mercury and close the groove.
On the accompanying Sheet of Drawing I show, in sectional elevation, a man-
hole embodying my invention.
A being the movable plate or door.
a is the flanged lip of same.
B is the groove or recess made in the frame C and which I fill with Mercury as
aforesaid.
D is the floating ring or plug.
By using Mercury in the groove I always maintain an air tight closing, with
great facility of inspection it only being necessary to lift off and replace the door
after inspection, in lieu of breaking and making the ordinary mechanical or cement
joint.
I may dispense with the plug or ring D, and I now find it preferable to make
the doors of iron protected by ."Barff's" process, but I reserve the right of using
any material which I may find suitable; and I may where desirable permanently
fix in the movable cover a thick glass inspection plate.
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. The movable plate or door (A) of a man-hole having a flange (a), in com-
bination with a frame (C) having a groove or recess (B) receiving Mercury,
substantially as described and for the purpose specified.

page_text: 2. In a man-hole having the plate or door A with flange a and frame C with
groove B, the plug or ring D, applied substantially as described for the purpose
specified.
3. The sealing of doors or man-holes against escape of air and gas substantially
as described and shown on the accompanying Sheet of drawing.