Material Handling Equipment

Conveying, transporting and bridging gaps

The units used for transferring the product from one processing unit to another in an extruded foods plant must be able to meet the following criteria:

  • Efficient, high volume transportation without damage to the product
  • Maintenance of highest possible standards of hygiene
  • Flexible

To transport raw materials for extrusion, Schaaf uses a special flexible screw conveyor. This is a specially designed conveyor that has an outer food-grade plastic pipe and a flexible steel spiral inside. The complete unit can be installed as required (not necessarily straight) to compensate the actual gap between the 2 units being bridged. The spiral is directly coupled with the motor shaft and rotated at high speed. The special operating method of this unit ensures high transportation rates whilst at the same time ensuring that the various components of the raw material mix are not separated during conveying.

For extruded products, Schaaf usually employs a pneumatic transport unit that carries the extrudate to the next processing unit, installed directly at the extruder exit (or at the exit of any special cutting unit used immediately after the extruder). The pneumatic transport unit may have a blower or a suction system. The product at this stage is still flexible enough not to be damaged when transported through pneumatic transportation piping. At the outlet end, a cyclone is used to separate the product from the conveying air (the product drops down; air is released from the top of the cyclone).

The advantages of pneumatic transport are:

  • Low equipment costs
  • Virtually no maintenance required
  • Flexible design and configuration
  • Extremely easy to maintain a high level of hygiene


Products, such as co-extruded, filled products, are heavier and demand a type of gentle handling that cannot be provided by pneumatic transportation. Such products are conveyed from one processing unit to another using a wide range of inclined belt conveyors.

Inclined and flat belt conveyors are also used to bridge gaps between processing units that cannot be moved but must be used in various configurations to make different products.

Schaaf uses vibratory chutes to transport the product after it has become more sensitive to breakage e.g. after drying or after seasoning has been applied. These chutes transfer the product over short distances with a high level of efficiency. They require very little installation space and can be cleaned easily. They also allow the operator to inspect the product at various intermediate production stages.