Year: 1897

page_text: I, SVEN PETTER AXEL ANDERSSON, of Backasands gard, Ödeshög, in the Kingdom
of Sweden, Engineer, 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 :-
f
In this centrifugal churn the operation upon the cream, necessary for the formation o
butter, is effected by means of a grating fixed in the rotating cream container and
the cream is allowed to strain through the said grating. The grating, which as a
whole forms a radial wing or occupies a position inclined to a radius, is composed of
thin and wide knives or blades turning their edges in a direction opposite to that in
which the bulk of the cream rotates. The blades viewed in cross section, are not
quite perpendicular to the radius of the cream container, this deviation varying in
amount for the different blades, and as a result the latter offer a resistance to the
body of the cream which causes the latter to be divided into layers or films which
acquire differing angular velocities and consequently develop friction one against the
other. The effect obtained by this operation is very good, so that the churning
process may be completed in a few minutes.
In the accompanying drawing the cream-container is shown in vertical section in
Figs 1 and 2 viewed from two different sides, and in fig 3 in horizontal section. The
cream container A is mounted together with its shaft B in a frame C where it can be
rotated by suitable gearing. Its upper end is provided with a central opening
through which is inserted a firm support D of square or other suitable section which
is provided at its lower end with a steadying pin E entering into a small bearing
arranged in the bottom of the container A. The upper end of the support D enters
and fits into the removable cross bar F of the frame C, being thus kept firmly in
place and prevented from turning. To the support D is attached a frame G in which
the above mentioned thin knives or blades H are mounted. The grating thus formed
may occupy a vertical position but it is more suitable to give it a slight inclination to
the vertical plane as shown in the drawing, and the entire grating may be made
slightly twisted or warped, so that its inclination increases in the direction of the
periphery of the container all for the purpose of causing the knives to cut through
the body of cream with increased facility. Regarding the different knives it should
also be noted that they are somewhat inclined to the axis of rotation of the container
their broad side being turned toward said axis, as seen froin figs 1 and 3. The

page_text: outermost knife viewed in cross section, stands perpendicularly if its slight bend
towards the radius drawn from the axis of the container be disregarded the next one,
however, is not quite perpendicular to the radius and the following one is placed still
more obliquely and SO on so that the innermost knife has the greatest
obliquity. The knives thus occupy diverging positions with respect to one another.
If the container be rotated in the direction shown by the arrow in fig. 3 so that the
cream enters between those edges of the knives that are set closest together,
the cream will be spread inwards towards the centre of the container, when
passing between the knives before being subsequently thrown outwards by the
centrifugal force. Owing to the differing resistance, this being greatest near
the innermost knife and decreasing in the outward direction a motion is created in the
creain as if it were approximately divided into layers corresponding to the apertures
between the knives, said layers sliding one on another. This may serve to explain
the great efficiency attained with this churn. The knives, which are suitably made
slightly warped, are produced from stiff sheet metal with or without such known
means as corrugations projections or the like such as are commonly employed for
working the cream. The action of the grating will also be evidently the same as
described if the grating be laid down so as to give the knives a horizontal position.
The cream will then be pressed towards the bottom of the container and thus towards
the direction of the centre of the latter. The butter formed by the above mentioned
inward motion of the cream (or milk) is thrown towards the centre where it collects
in the portion of the container not occupied by the cream, forming a more or less
It is also possible to use two or more gratings proceeding from the
coherent mass.
same support D.
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. A centrifugal churn having a grating consisting of a number of thin and broad
knives or blades placed side by side comparatively close together and occupying such
a position that viewing the knife (blade) in cross section, it runs concentric or nearly
concentric with the direction in which the body of the cream rotates, for the purpose
of causing the cream to pass in thin layers between the knives or blades substantially
as set forth.
2. In a centrifugal churn as firstly claimed, the arrangement of the knives or blades,
to diverge somewhat from one another, for the purpose of causing the cream entering
between the edges of the most closely situated knives to be spread as it passes
between the knives or blades and owing to the varying inclination of the latter
creating a sliding motion of the cream layers with reference to one another,
substantially as set forth.
3. In a centrifugal churn as firstly claimed the arrangement of the knives or
blades so as to be inclined somewhat to the radius of the container in such a manner
that they direct the body of cream to pass inwards towards the centre of the container,
substantially as set forth.
4. In a centrifugal churn as firstly claimed, constructing the entire grating
which is slightly warped so that it is inclined to the plane defined by the axis of
rotation of the container, substantially as set forth.
5. In a centrifugal churn as firstly claimed, the employment of knives or blades
which are slightly warped substantially as set forth.
6. The construction of churn substantially as described and shewn on the
drawing.
JENSEN & SON
77 Chancery Lane London W.C. Patent Agents.