204 Chapter 9
and churning/rotating speed are controlled to
meet cream and product requirements.Working Section
Typically there are two working sections
linked by a vacuum chamber in butter making
machines. Working section 1 comprises
augers for transportation of the butter and
also working elements, i.e., working vanes
and perforated plates. The butter mass is
kneaded in this section, expelling buttermilk
before addition of water and/or salt slurry. If
the augers operate at too low a speed they
will not squeeze suffi cient buttermilk out of
the butter.
Butter is forced through a regulating gate
between working sections 1 and 2. By adjust-
ing the apertures of the gate, the counter pres-
sure on the butter can be adjusted and hencebuttermilk; excessively large or small grains
retain too much moisture. The churning
process only takes a few seconds and a
mixture of butter grains and buttermilk then
fl ows into the separating chamber.
Separating Section
The separating section consists of a horizon-
tal rotating cylinder in which two operations
are performed. The fi rst part of this section
contains beaters to continue churning the
mixture of buttermilk and butter grains,
causing larger clumps to form and more but-
termilk to be expelled. A perforated fi lter, or
separation drum, then separates the butter-
milk from the butter, while the rotation of the
drum encourages further clumping of the
grains. Operating parameters of the churning
and separating sections such as temperature
Figure 9.4. Schematic outline of a continuous butter making machine (APV Unit Systems, Denmark). Fearon
and Golding (2008).