IMPROVEMENTS IN APPARATUS FOR MAKING INFUSIONS OF COFFEE, TEA AND OTHER SUBSTANCES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I OSCAR ARNDT, partner in the firm Gebr. Arndt of Quedlinburg in Germany,'
Manufacturers, do hereby declare the nature of said Invention for "IMPROVEMENTS
IN APPARATUS FOR MAKING INFUSIONS OF COFFEE, TEA AND OTHER SUBSTANCES,"
to be as follows:
This Invention relates chiefly to improvements in coffee machines and has for
its object to cause the boiling water to pass in a uniform manner through the layer
of ground coffee so as to produce a uniform infusion from the same..
For this purpose I place the ground coffee (or other material) in a cylindrical,
vessel between two sieves, the lower one of which may be fixed while the upper one
is removable and held down by a specially constructed lid.
"
The upper sievo is secured with its edges to an annular lid similar to a valve
and resting on a narrow valve seat attached to the inside of the vessel, which valve
seat may either form part of a conical or of a spherical surface.
A bar, extending diametrically across the top of the lid, projects from the latter,
on both sides, so as to form two noses which rest against two guides or projecting
ledges attached to the inside of the vessel diametrically opposite each other.
The said guides or ledges are inclined and partly or wholly curved, so that by
introducing the two noses under the upper extremity of the two ledges and then
turning the lid, the latter is forced downward and describes a sort of screw motion,
until it has reached the annular seat of the lid, in which position the lid remains
until it is again turned upward by hand,
:

page_text: I, OSCAR ARNDT, partner in the firm Gebr. Arndt, Quedlinburg, in Germany,
Manufacturers, do hereby declare the nature of my Invention for IMPROVEMENTS
IN APPARATUS FOR MAKING INFUSIONS OF COFFEE, TEA, AND OTHER SUBSTANCES,
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 more particularly to coffee machines or appliances for
making infusions from ground coffee, and has for its object to construct. a simple
apparatus adapted to treat in a uniform manner the entire quantity of coffce
employed, so as to extract and utilise as much as possible of the aromatic and
usoful constituents, while the injurious or useless substances remain undissolved.
My improved coffee machine, like many of those already known, comprises a
metallic vessel containing three superposed compartments, namely the lowest
compartment or receptacle for the infusion, tho intermediate compartment or
receptacle for ground coffee, and the upper compartment or receptacle for hot
water.
The intermediate compartment is situated between a pair of sieves, the lower
one of which may be fixed to the vessel, while the upper sieve forms a removable
cover adapted to be pressed down and closed tightly by a special contrivance.
In the further description reference will be made to the annexed Drawing of
which Fig. I is a vertical scation through the principal parts of an apparatus
embodying my Invention and Fig. III a horizontal section through the upper
compartment G of the same, while Fig. II is an inside view of the developed upper
and middle compartments showing a special fastening device, and Fig. IV shows
the upper sieve or cover in detail.
The ground coffee being placed upon the fixed lower sieve a and firmly pressed
down by the upper sieve b, provided with a handlo 6', hot water is poured into the
upper compartment G. It will then pass slowly and uniformly through the layer
of coffee, thereby dissolving and carrying off a larger or smaller portion of its
constituents, according to the time required for its travel, which again depends on
the thickness of the layer of coffee, and the relative size or area of the two sieves.
For a machine of a given capacity the two sieves must therefore be a certain
distance apart and have a certain size and ratio of areas. I generally make the
lower sieve smaller than the upper sieve and therefore the middle compartment B
conical.
The principal feature of novelty in my apparatus is the means of producing and
maintaining a tight fit between the removable cover and the body of the vessel
which is essential for obtaining a good result with such apparatus, because an
imperfect joint will not only allow an excess of water to pass into the layor of
coffee and ground coffee to riso into the upper compartment but will facilitate the
subsequent escape of aromatic vapours from the coffee contained in the lowest
compartment.
In order to obtain a perfect fit, I make the contact surface c of the lid similar
to that of a valve, and the corresponding contact surface d of the vessel similar to
that of a valve sent, preferably conical or spherical, as shown in the Drawings, and
for applying the pressure necessary for keeping the surfaces in uniformn contact,
I employ a sort of bayonet lock, consisting of a pair of circumferential projections
and a pair of inclined guides, preferably by securing to the lid a cross bar 8, the
extremities n n' of which project beyond the lid and to the inside of the vessel a
pair of inclined guides ƒ ƒ³ diametrically opposite each other, (see Fig. II).

page_text: In introducing the lid, the latter is turned so that the projections or pins n, n',
come under the rounded upper extremities of the inwardly projecting guides f,
after which the necessary pressure upon the lid and a tight fit may easily be
obtained by turning the lid so as to bring the pins n and n¹ towards the lower
ends of the guides ƒ, ƒ'.
When once turned down, the lid is held in place by friction.
It will be seen that in the improved coffee machine, the pressure upon the lid is
obtained by means of inclined or helical surfaces, as in the ordinary screw action,
but the improved locking device is more convenient in action, and less liable to get
out of order than ordinary screw joints.
The vessel is preferably made of sheet metal, and the different compartments may
either be formed in the same piece or vessel or composed of separate parts. The
seat & may be formed by a soparato ring, secured to the interior of the vessel, as
shown in the Drawing, or it may be formed by the conical wall of the central
compartment.
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. In coffee machines having a removable sieve or cover over the layer of coffee,
the means of producing and maintaining a tight fit between the cover and the
body of the vessel, substantially as and for the purpose described.
2. The combination of contact surfaces c and d (similar to those of valves) with
projectious n, n¹ and inclined guides f,f¹."