An Improved Non-return Valve for Air and Gases.
Year: 1899

page_text: Date of Application, 8th Feb., 1899 -Accepted, 11th Mar., 1899
COMPLETE SPECIFICATION..
An Improved Non-return Valve for Air and Gases.
We, FRANZ RICHTER, Decorative Painter, of 70, Moltkestrasse, Koln a/Rhine,
Germany, and HEINRICH BOPP, Mechanic, also of Koln a/Rhine, Germany, 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:-
The non-return valves at present used for the purpose of pumping air and
other gases, for example, into pneumatic tyres, etc., all have the drawback,
especially when there is a back pressure to contend with, that the pumping can
only be carried on with great difficulty, and, consequently with a considerable
expenditure of force. The cause of this is, in, many cases, the unsuitable con-
struction of the valve whose body, in some cases, is caused to press on the valve
seat not only by the action of the air pressure but also by special organs, such as
spiral springs, etc. In other cases, take for example the Dunlop valve, whilst
spiral springs or such like are not used yet the pumping in of air is still rendered
difficult owing to the necessity of forcing out side-ways the strong india-rubber
tube which is slipped over the outside of the air admission valve, in order that the
air may make a way for itself, in a downward direction, along the sides of the
valve tube.
The object of the present invention is the provision of a non-return valve which
will not possess the aforesaid inconvenience, and in which the injected air is
prevented from escaping solely by the pressure of the air itself. The arrangement
by which this object is attained consists mainly of a small bag made of any suitable
elastic material, such for example india-rubber, which is closed at its lower end
by flattening the sides and vulcanizing them together with the exception of a
small portion at the centre of the bottom which constitutes a narrow passage way
or slit through which the air can pass. This bag presents, in elevation, practically
the shape of the reed of a wind instrument.
And in order that our said invention may be properly understood we have
hereunto appended an explanatory sheet of drawings which shows, by way of
example, one mode of constructing the non-return valve.
Fig. 1 is a vertical section through the centre of the valve whilst Fig. 2 is an
elevation of the elastic bag.
Between the internal passage a¹ of the valve box a and the mouth piece b by
which it is closed a small india-rubber bag c is fitted. This bag, which is drawn
over the exterior of the said mouthpiece, has a thin wall of cylindrical shape at
its upper end where it is provided with a rim or bead c² which rests upon a
circular seat cut out at the upper end of the valve box and is held tightly in
position against this seat, by means of the collar 62 on the exterior of the mouth-
piece b. The lower end of the bag has its walls flattened and vulcanized together
so as to present the appearance shown in Fig. 2 in side view, and Fig. 1 in
section. A narrow passage or slit d is left between the flattened sides through
which the air can pass when forced into the bag under pressure.

page_text: When air is pumped into the channel of the mouthpiece bit enters the
bage and escapes freely therefrom into the passage at of the valve by widening
out or forcing apart the elastic walls of the passage d. The compressed air in
the passage cannot return through the passage d owing to the fact that its
pressure, acting equally in all directions, forces (owing to its action on the out-
side of the bag) the side walls of this passage d tightly together. The passage.d
or mouth of the bag will be closed the tighter, as will be readily understood, the
more the pressure of air within the space a¹ increases.
This non-return valve, besides its other advantages, will never fail to work
properly which is not the case with the ordinary valves which fail to work in
some cases through the inefficiency of the action of the valve spring, and, in
others, through the bursting or brittleness of the small india rubber tube of the
valve, as in the case of the Dunlop and such like valves.
The valve can be very simply and cheaply constructed.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we consider novel and desire to claim is;-
A non-return valve having an elastic body inserted between the valve box and
the mouthpiece characterized by the body being made in the shape of a small bag
whose lower end has its side walls flattened and vulcanized together with the
exception of a narrow central passage way through which the air can pass, sub-
stantially as and for the advantages hereinbefore set forth.
Hated this 7th day of February 1899.
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.