Improvements in or relating to Packing for Manhole Covers.
Year: 1897

page_text: Date of Application, 7th Dec., 1897-Accepted, 8th Jan.,
1898
CUALI LEIE DIEUITIVATION.
Improvements in or relating to Packing for Manhole Covers.
(A communication from RICHARD ADOLF JAENICKE of 3A Elisenstrasse, Dresden, in
the Empire of Germany, Manufacturer.)
I, ALFRED JULIUS BOULT, of 111 Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
Although metallic packing is generally well known, the joints between the covers
and manholes and other openings in boilers and similar vessels have hitherto
been made tight by means of hemp or rubber-rings which are open to many objec-
tions. Hemp is quite unsuitable owing to the high pressure used and to the long
periods during which they are in use, between two cleanings of the boiler. Rubber
rings cannot withstand the high pressure and temperatures to which they are
exposed for long periods, and when they once become defective in any place, no
extra tightening is of any use, but the working of the boiler must be stopped and
the packing renewed. Rubber rings are besides very expensive and when the
manhole cover is taken off, the rubber-ring is useless not only for its original
purpose but also for any other useful purpose.
The inventor has found in his experiments that a simple ring of lead cast or
formed without joints and having preferably a round cross-section, which has not
been hitherto used in this shape and for this purpose, is perfectly free of all the
drawbacks of the packings for the manholes hitherto used. It keeps excellently
tight even when subjected to the greatest strain for long periods and even if it is
useless for the same purpose after the manhole-cover has been removed, the
material is still available for other uses or for re-casting.
The accompanying drawing illustrates a ring according to the present invention
and its utilization for rendering tight the joint of a manhole-cover. Figure 1
shows in plan a part of a boiler with the manhole and manhole cover, Figure 2
being a section on the line 2-2 of Figure 1. A is a lead ring of originally round
cross-section but which has been slightly deformed by the pressure of the screws,
and has therefore an elliptical cross-section. The cross-section may however be
elliptical from the first; if of circular cross-section it may not always be necessary
to flatten it to make a tight joint. The ring A is as usual placed between the
edge B of the man-hole and the cover C.
An advantage of the leaden ring, which has not before been mentioned, is that
nothing remains sticking to the contact-surfaces, as with rubber and like packings,
the surfaces, on the contrary, remaining smooth and clean.
In case of an ordinary man-hole the thickness of the rings may be about
16 millimetres.

page_text: Having now particularly described and ascertained the nature of the said
invention as communicated to me by my foreign correspondent, and in what. manner
the same is to be performed, I declare that what I claim is:-
A packing ring for man-hole covers formed of a closed ring of lead of a circular
or elliptical cross-section, substantially as described.
Dated this 7th day of December 1897.