The Vermont watchman. [volume] (Montpelier, Vt.) 1883-1911, 1897-02-17
which it moves. In the ordinary sem

which it moves. In the ordinary sep
arator making 5000 revolutions per
minute the force thus developed is
enormous, as the pressure which the
contained milk exerts upon the wall of
the separator bowl is between 500 to
800 pounds per square inch, and as this
pressure increases as the square of the
rate of rotation, it can readily be seen
bow dangerous it is to run separator
at speed greatly exceeding that ad-
vised by the manufacturer. To make
this perfectly plain, suppose the pres.
sure in bowl rotating 5000 times per
minute to be $50 pounds per square
inch; then if the speed be doubled, or
II 900 per minute, the pressure would
be four times $50 pounds, or 1920
pounds per square inch, and the bowl
would be liable to explode.
The practical problems, then, which
have confronted separator manufactur-
ers have been to 80 construct the bowl
that it will Withstand the enormous
pressures produced, and to devise
means for continually Withdrawing the
skim milk which collects in the outer
portion of the milk ring, and the cream
which collects at the inner surface
close to the axis of rotation, and these
objects are attained in slightly differ
ent ways in the various kinds of sepa-
ratOrs.
So much for the theory. Now as to
the practical rules governing the sepa-
rator management:
AS a separation of the cream de-
ponds entirely upon the centrifugal
force, and since this force depends
upon the rate of rotation of the bowl,
it is of the first Importance, in order to
have clean skimmipg, that the proper
speed should be constantly maintained.
Moreover, this speed should not be
greatly exceeded, as it is dangerous to
do so.
A matter also of considerable impor-
lance is the length of time that the
centrifugal force is allowed to act upon
the amount of milk separated per hour.
The slower the milk is run through the
separator, the more perfect and COM
plete is the separation, for, in the same
way as in the gravity systems, certain
elobules to travel to their proper posi-
lions.
The warmth of the milk should be
carefully attended to, for when it is
cold the separation is incomplete. This
is due to the fact that warm milk is
less Vicious than cold milk, and thus
there is less resistance offered to the
movement of the globules. Practically,
any temperature between So and 100
degrees Farenheit gives very good re-
suits.
The steadiness with which the bowl
runs also affects the completeness of
separation, for when the bowl shakes,
the layer of cream which has taken a
position on the inner surface of the
milk ring, is constantly being mixed, to
slight extent, with the layer of skim
milk which is next to it.
When an engineer wishes to deter
mine whether the steam which he is
using in his engine is doing all of the
work which it capable, he does not say
that he gueses that the valves are in
proper position and are working in
unison, but he applies an indicator and
obtains record of the steam pressure
in the cylinder at every instant of the
stroke and then he knows whether
everything is all right. Users of sep
aratOrs also have way of telling
whether their separators are working
satisfactorily. Reference is made to
the Babcock test. Test often; it pays.
II there is any considerable loss, find
out what is the trouble. Probably the
milk is being run through too fast, or
possibly the speed is not high enough,
or the milk is too cold. Watchfulness
here puts butter in the tub, and in these
times of low prices the profit often
comes from the saving Of trifles.-Hor-
ace Atwood, in Hoard's Dairyman.