IMPROVEMENTS IN VENT PEGS FOR CASKS OR VESSELS FROM WHICH BEER OR OTHER LIQUID IS DRAWN OFF FROM TIME TO TIME
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by Robert Mann Lowne at the Office
of the Commissioners of Patents, with his Petition, on the 15th
September 1865.
I, ROBERT MANN LOWNE, of No. 17, Bartlett's Buildings, Holborn, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN VENT
PEGS FOR CASKS OR VESSELS FROM WHICH BEER OR OTHER LIQUID IS DRAWN OFF
FROM TIME TO TIME," to be as follows:-
This Invention has for its object improvements in vent pegs for casks or
vessels from which beer or other liquid is drawn off from time to time.
In order that the liquid may flow freely from a cask or vessel it is necessary
that air should be able freely to enter it, whilst at the same time it is un-
desirable that the gas or air within the cask or vessel should be able to escape
from it, otherwise the beer or liquid becomes flat. Self-acting vent pegs have
in some cases been employed by which it has been attempted to admit the air
to the cask or vessel as required, and prevent its escape; and such vent pegs
have in some cases been furnished with valves of india-rubber of various
kinds; such vent pegs, however, do not as I believe work satisfactorily in
consequence of their requiring, when constructed as heretofore, a considerable
vacuum within the cask before they will open. Sometimes the construction
of the valve has been such that a considerable stretching of the india-rubber
is necessary before the valve opens; sometimes the construction is. such that
the vacuum is able to act efficiently only on a very small area of the valve,
namely, the area of the aperture which the valve closes.

page_text: Now according to my Invention I employ in the vent peg a valve of india-
rubber, so arranged, as I will immediately explain, that the vacuum may be
made to act on any desired area, whilst at the same time the slightest
deflection of the valve serves to open the passage. The cone or peg which
enters into the cask or vessel has a passage through it, at the upper end of
which is a chamber of any desired size, closed at the top by a diaphragm of
india-rubber fixed over it, so as to close it air-tight, and in the centre of this
diaphragm is an opening sufficient to give free passage to the air. Over the
diaphragm a cover is screwed on to the chamber at the top of the cone or peg,
and on this cover is a projection which just touches and closes the hole in the
india-rubber diaphragm, when the pressure is equal on either side. Thus it
will be seen that the whole under surface of the diaphragm is exposed to the
pressure in the cask or vessel, whilst the upper surface is exposed to the
pressure of the air, so that immediately the external pressure becomes slightly
in excess of the internal, the diaphragm is deflected and the air enters freely.
It is not essential that the air passage should be through the diaphragm itself,
as the arrangement may be modified (although not I believe conveniently) so
long as practically the whole surface of the diaphragm on one side is exposed
the effective pressure of the atmosphere, and that on the other side to the
vacuum within the cask or vessel, and so long also as the arrangement is such
that the deflection of the diaphragm at once uncovers the air passage.