Danish firm Hybren has come up with a neat way of getting rapeseed clean before pressing it for culinary or biodiesel use.

Instead of passing seed over flat or cylindrical screens, it uses a helical screw rotating inside an outer cylinder with three different sizes of holes in it.

Changing from one to another involves simply turning the outer part and the pressure of the screw stops the holes blocking. Output is 20-100kg/hour and the unit costs £750 in Denmark.

Hybren also makes oil presses plus an interesting all-in-one unit that combines seed cleaner, oil press and a burner unit that uses the leftover meal to heat the farmhouse.

Energy content of the meal is anything from 10-30% more than wood pellets, depending on how much oil you leave in.