Specialist for fibrous material

Straw mill SD


Straw mill SD

Specialist for fibrous material

Technical Data

Drive power
90 – 250 kW
Grinding chamber area
1.84 - 3.60 m2
Permissible weight
1900 – 2900 kg
Grinding chamber diameter
1200 mm
Sieve width
640 – 1250 mm

Technical details
  • Geometry of the grinding chamber specially designed for comminution of fibers
  • Suction and transport of material from the grinding chamber via aspiration air
  • Variable particle size spectrum by changing the beater peripheral speed (when using a frequency converter)
  • Robust welded steel construction for industrial continuous operation. With a second set of beams, the machine is immediately ready for operation again.
  • Standstill monitoring with door safety device
Machine types
SD 12 SD 25
Grinding chamber diameter (mm) 1200 mm 1200 mm
Screen width (mm) 640 mm 1250 mm
Grinding chamber area (m²) 1.84 m² 3.60 m²
Dimensions and Weight
Length* x width x height (approx. mm) 2340 x 1550 x 1620 mm 3150 x 1550 x 1620 mm
Weight without motor (approx. kg) 1900 kg 2900 kg
Motor size (kW) 90 - 132 kW 160 - 250 kW
Speed 50 Hz/60 Hz (rpm) 1500/1800 1500/1800

* Depending on motor size Measuring surface sound pressure level < 88 dB (A) (under load)

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Specialist for fibrous material



The straw mill SD has been specially designed for crushing fibrous material such as

  • straw
  • hay
  • alfalfa
  • miscanthus
  • hemp
  • jute
  • coconut fiber

A comb in the inlet area as well as the special geometry of the grinding chamber grind the fibres particularly efficiently. Foreign bodies are separated by means of a catch pocket that is accessible from the outside. The beaters are fixed to carrier frames, which can be quickly and easily changed with a supplied device. This means that it only takes a few minutes to change the beaters and downtime is reduced to a minimum.

Specialist for fibrous material

The straw hammer mill with optimized geometry

The straw mill SD is specially adapted to the grinding of straw due to its special geometry. The result is high throughput and low energy consumption. Low bulk densities and very large volumes of processed straw pose no problems for the Straw Mill SD. The straw can be easily broken down to the typical fineness of 10 mm or less (depending on the specifications of the fermenter manufacturer) and is thus optimally prepared for anaerobic digestion. The dry straw is transported pneumatically in an energy-efficient and low-wear manner.

Like all our mills, the straw mill SD meets the highest industry standards and is designed for continuous use over many years. The straw mill SD series consists of two housing sizes for motorization from 90 kW to 250 kW drive power.

Once the straw has been broken down, we can efficiently and reliably mix it with your fermentation substrate or slurry so that it can be fed directly into the biogas plant after processing.

In straw mono-digestion, the Impra system can additionally be used as a stock preparation system to further break down the fibres in the process.

Our Straw mill SD
Your Advantages
SD Einlaufklappe SD Fremdkörperfangtasche SD Schiebetür

Efficient Grinding of Fibrous Products

  • Geometry of the grinding chamber specially designed for the size reduction of fibres
  • Intake and pneumatic transport of the material through the grinding chamber via the aspiration air
  • Optimised inlet with ripping comb, adjustable from the outside to the product properties
  • Large dimensioned inlet and outlet for high volume flows with low bulk densities
  • Variable grist spectrum by adjusting the beater circumferential speed (when using a frequency converter), screen perforation and beater configuration

Reliable Operation and Long Service Life

  • Robust welded steel construction for continuous industrial operation (24/7)
  • Grinding chamber equipped with wear elements to protect the housing, easy to change
  • Durable, optimised rotor design, dynamically balanced
  • To protect the screens: foreign body catch trap for impurities inside the grinding chamber

High Availability with Low Downtimes

  • Quick and easy change of beaters due to beater frame system, beaters can be changed outside the mill
  • With a second beater frame, the machine is immediately ready for use again
  • Rotor with short run-down time < 6 min without brake
  • A large sliding door allows easy and quick access to the machine interior
  • 3-part screen segments without frame, easy and quick to change segment by segment, clamped with chains

High Safety of Personnel and Plant

  • Standstill monitoring with door safety device
  • Pressure shock resistant and flameproof design (0.4 bar)
  • ATEX design according to zone 21 (II 2 D) inside and zone 22 (II 3 D) outside optionally possible
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