The MAC-75 apparatus is a multimode microwave reactor. It
contains 4 magnetrons (4 ? 1500 W, 2450 MHz) with a maximum
power of 6000 W delivered in 500 W increments. The stainless
steel microwave cavity has a capacity of 150 L and contains a
removable, rotating PTFE drum that allows up to 75 L of plant
material to be loaded. The rotation ensures a homogeneous
microwave distribution to the material inside the drum. The drum
circumference is entirely perforated to allow the vapour and liquid
to pass. The cavity has 6 external tube connections (one in the top,
one in the bottom and 4 in the sides) and is wrapped in removable
thermal insulation. The absorption of microwave power is con-
trolled by sensors placed on wave guides. The system automati-
cally adjusts the power delivered if absorption is too low. The
temperature is monitored by a Resistance Temperature Detector
(PT-100) inserted into the cavity. The cavity is able to work in deep
vacuum or as an open vessel. The functional deep vacuum is need
with plant material particularly. Interlocks on the door prevent
accidental opening during the process or when the cavity contains
liquid. The device is controlled by an industrial touch screen con-
trol terminal with an intuitive graphic user interface.