Volumetric Feeders fall into 3 categories:
- Batch Feeders – by controlling time a weight batch (Kg) is dosed.
- Rate Feeders – by controlling speed a variable speed rate (Kg/hr) is dosed.
- Recipe Feeders – by controlling both speed and time a variety of recipes can be delivered already mixed.
The RPM of the screw feeders can be adjusted by means of:
- Continuous mechanical variable-speed motors with manual or electrical control: Minimum flow rate equal to 1/5 of maximum flow rate.
- Continuous hydrostatic variable-speed motors with manual or electrical control: Flow rate having maximum value of approximately 0.
- Gearmotors with motors piloted by vector inverters and additional power ventilation, when necessary, with minimum flow rate equal to at least 1/10 of maximum flow rate.
Continuous volumetric feeders from 3 dm³/h to 40 m³/h.
(depending on the spirals/screws and reduction ratios used, from 1800 g/h to 21’000 kg/h considering a density of 0.6 kg/dm³).