Harvesting System Design and Performance - Engineering and Science of Biomass Feedstock Production and Provision - page 96

Fig. 5.11 Self-propelled forage harvester and different heads: a, mower bar; b, pickup; and c and
d, row crop, ear-corn snapper (d 2 ). Adapted from [ 21 ]
knives (see Fig. 5.10 ). The rotor diameterrangesfrom500 to 800 mm. The rotor
widthvariesfrom250mmforone-rowside-mountedmachinesto800 mmforself-
propelled forage harvesters. The peripheral speed of the rotor ranges from 15 to
20ms −1 . Higher capacity machines use spiral knives, and smaller machines generally
use straight knives. A cylindrical rotor offers better performance, higher reliability,
lower energy costs, and greater simplicity of construction than flywheel-type rotors.
The forage heads (Fig. 5.11 ) are classified into the following main categories:
• Direct cut or mower bar: Mower bar heads are suitable for direct cutting of
energy grasses. Direct-cutter heads are equipped with a reel to gather crop mate-
rial into an auger which feeds material into the feed rolls.
• Windrowpickup:Windrow-pickupheadsaregenerallyusedtopickupawind-
row formed earlier by a mower-conditioner. Retractable fingers and auger-flight
extensions feed the pickup biomass into the feed rolls.