6.2 Standard Internal Mixer—The standard internal mixer
shall have a chamber of 1575 6 50 cm3 volume and two rotors
with approximately 400-cm3 displacement volume, resulting in
1170 6 40-cm3 loading capacity. The slow rotor speed shall be
8.16 rad/s (77 rpm) and the gear ratio shall be 1:1.125. The
rotor wing tip to side clearance shall be 2.4 + 0.3, − 0.1 mm
(0.094 + 0.010, − 0.005 in.). The mixer shall be equipped with
a thermocouple for measuring and recording batch mixing
temperatures. The thermocouple shall be installed through the
end frame and shall protrude into the mixing chamber 25 6 2.5
mm (1 6 0.1 in.) measured along the top side of the
thermocouple probe. A ram that is 56 6 3 mm by 140 6 8 mm
(2.2 6 0.1 in. by 5.5 6 0.3 in.) shall exert a force of 1.27 6
0.06 kN (285 6 14 lbf) on the batch in the chamber. The sides
shall be hinged to swing open, made of cast stainless steel and
jacketed for controlling temperature by means of a circulating
liquid or steam. The end frames shall be of ductile iron that has
a 0.20 6 0.02-mm (0.008 6 0.001-in.) thick chrome plating on
the working surfaces. Rotors are of stainless steel, nitrided,
drilled, and equipped with rotary unions for controlling the
rotor temperature by means of a circulating liquid or steam