Sprout-Matador A/s

Andritz Feed & Biofuel A/s

Anders Flarup-Knudsen

In the extrusion of feed-stuff pellets and relevant consumer products, the extruded products are subject to expansion as a result of the boiling of their water content when the products, after being exposed to high extrusion pressure and a correspondingly high temperature, are discharged to the atmosphere through the extrusion nozzles. Such an expansion is directly aimed at, but it is desirable to be able to control it, which is difficult by adjustment of the ordinary process parameters. With the invention it has been found that the expansion which arises can be controlled in a highly constant manner, i.e. by carrying out the extrusion into a closed chamber in which an over-pressure of a few bar is established in relation to the atmospheric pressure, and which can be regulated. The extrusion products can be continuously discharged from this chamber, or they can be discharged intermittently in portions. The over-pressure moderates the momentary development of steam in the extruded product, and the product is given time to stabilise before being discharged to atmospheric pressure, so that the subsequent further development of steam influences the structure of the product only to a minor degree.

Method and apparatus for extrusion of expanding water holding products such as foodstuff particles or feeding stuff pellets

The inventions relates to an extrusion apparatus suited for water-containing products which heat-expand by internal boiling of water by pressure relief after passing through extrusion nozzles. The apparatus comprises a) an extruder, which at the outlet end thereof comprises a nozzle plate, b) a pressure-controlling chamber for controlling the pressure on the outlet side of the nozzle plate, said pressure-controlling chamber possibly containing a cutting-off unit, and c) a sluice unit downstream of the pressure controlling chamber. The apparatus furthermore comprises that the pressure-controlling chamber and sluice unit being releasably interconnected and at least the sluice unit being mounted movably in and out of the product stream. Hereby may the apparatus start up without connecting the sluice and easily connecting the sluice, when the product is sufficiently stable for the correct function of the sluice, so that the problems during start-up of the apparatus, such as the unstable and the relatively wet products tendency of blocking the sluice is substantially avoided.

Growing community of inventors

Esbjerg, Denmark

Anders Flarup-Knudsen