An Improved Method of and Apparatus for Determining the Quantity of Fat in Milk.
Year: 1889

page_text: Date of Application, 28th Dec., 1889-Accepted, 15th Feb., 1890
COMPLETE SPECIFICATION.
An Improved Method of and Apparatus for Determining the
Quantity of Fat in Milk.
I, IVAR KNUT LINDSTRÖM, of Akerby near Oerebro, in the Kingdom of Sweden,
Estate owner 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 process and apparatus which forms the subject of the present invention has for
its object to determine the percentage of fat in unskimmed milk or in cream in a
more certain, quick, and simple manner than has heretofore been possible.
The principle of the said invention consists in producing the butter fat in a solid
state.
The improved method possesses many advantages over the older methods in which
the fat is produced in a liquid or semi-liquid state. Some of these advantages are as
follows a great number 80 to 100 samples may be tested at a time the subjecting
to centrifugal action of these takes only 10 minutes; the tests may be read many
hours after being subjected to centrifugal action and even so long after as the next
day, and the apparatus is reduced to the very simplest form.
In order to obtain the fat in a solid state from a certain quantity of milk, I add
to the milk matter capable of dissolving the caseine but which does not affect the
butterine. This matter may consist of hydrochloric acid either alone or mixed with
acetic acid or sulphuric acid.
The mixture of milk and the dissolving agent is treated in a centrifugal apparatus
under an afflux of water having a temperature of, first 50 to 60° C. and then 8 to 10° ('.
In this way the fat is separated in a solid state and is measurable.
In the accompanying drawing
Figures 1 to 7 represent an apparatus adapted to be arranged in a centrifugal
apparatus; its construction being such as to adapt it to the de Laval separator.
The apparatus may however be modified so as to adapt it to other centrifugal
apparatus.
Figures 8 and 9 show a modification of the first named apparatus, intended, when
inserted in a stand (not shown on the drawing) to be driven by hand thus adapting
it for use in dairies and the like, which have no other machine power at their
disposal.
Figures 1 and 2 show in plan and elevation a ring shaped centre a of metal
provided with a frame b; this centre has 8 slots, c projecting radially.
Figures 3 and 4 show in plan and elevation and
Figure 5 in section on the line 5. 5 a holder with test glasses e inserted therein.
This holder consists of a shell of tinned plate or other material and is movable on an
arm which is sunk horizontally in one of the slots e. There are 8 such holders so
arranged that the test glasses assume a horizontal position, radial with relation to the
axis of the separator. The test glasses e are cylindrical glass tubes closed at one end,
the inner diameter of which is so small, that no water flows out when the tube is held
horizontally.
Figure 6 shows in vertical section on the line 6, 6 and Figure 7 in horizontal
section on the line 7, 7 a de Laval separator drum, into which is inserted the centre a
with a holder d containing 10 test glasses e.
Figures 8 and 9 show a modified arrangement of the apparatus intended for
manual power. p is a spindle, which can be inserted in a stand and to which a
rotatory motion of about 2000 revolutions a minute may be imparted by means of a
common gear.
k is a turned bowl of metal fixed at p, at the inner circumference of
which are arranged 8 to 10 pair of flanges having for their purpose to keep the
holders in place. In the bottom of k is a hole ; m is a lid arranged to be screwed

page_text: on the bowl k, at the lower side of the said lid is secured a pipe n, which, near the
centre of the lid, passes, through the same, and through which pipe water can during
the centrifugal action pass in to k through it, out through o, and be caught by a
circular plate reservoir (not shown in the drawing).
The testing is effected in the following manner.
In a common test-tube 10, cub. c. m. of milk is measured up by means of a pipette
and likewise an equal quantity of the dissolving agent to, be use 1. The mixture is
shaken so as to well divide the caseine pre ipitate and is poured into one of the test-
glasses e. A small quantity of the mixture is then pressed out, by means of a shoulder
which exactly fits into the test-glass, so that the liquid column may always be of the
same length. The test-glasses are then placed in a tubular frame and exposed either
immediately or subsequently to a boiling temperature for 15 minutes they are then
placed into the holders d (9) which are either introduced into the centre a (the bowl k)
which has previously been inserted into the inner ring shaped part of the separator
drum. The separator drum is now continuously put in motion and is brought up to a
speed of 2000 to 3000 revolutions a minute under an afflux of water of 55 to 60° C.
This is continued for 5 minutes, and water of 10° C. is then let in, which for another
5 minutes is caused to pass through the separator after which the separator is stopped.
The holders are taken out and the tests may be read either immediately or
subsequently. In the test-glasses e the fat will have deposited itself in a semi-
transparent layer with distinct edges and it may be measured distinctly and
accurately by means of a seale provided with a vernier.
By means of the apparatus a person is able to effect from 80 to 100 tests in half an
hour exclusive of sample taking and reading and it has been proved that the results of
the milk tested by the said apparatus differ from that of chemical analysis by only
01% maximuni.
이
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
First. For determining the percentage of fat contained in milk by dissolving the
caseine and subjecting the milk mixture to centrifugal action, the operation of trans-
forming the butter fat in a solid state by subjecting the saine to successive centrifugal
action at degrees of temperature above the melting point of the butter fat and below
its fixing point.
Second. The improved apparatus for performing the operation indicated in claim 1
consisting partly of a ring shaped centre, which may be placed in a centrifugal
apparatus and provided with radial slots, and arms, which may be arranged horizontally
in these slots, each arm being provided with a holder movable in its longitudinal
direction, a number of cylindrical glass tubes closed at one end and of so small an
inner diameter, that water will not flow out when the tubes are placed horizontally,
which glass tubes are inserted into holders and in which the fat by means of centri-
fugal action is separated from the milk mixture in a solid state and measured up.
Third. The modified arrangement of the apparatus indicated in claim 2 consisting
of a bowl of metal fixed on spindle, the said bowl being at its inner circumference
provided with flanges between which are placed bolders containing the test-glasses
indicated in the preceding claim and in the bottom of the bowl a hole permitting
the water to pass out under the centrifugal action, a lid screwed in the bowl
provided with a pipe passing through the lid and secured at the other side, through
which water can pass into the bowl under the centrifugal up action.
Dated this 28th day of December 1889
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant