Determining external friction angle of barley malt and malt crush
¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague 6-Suchdol, Czech Republic
²University of Life Sciences Prague, Faculty of Engineering, Department of Electrical Engineering and Automation, Kamýcká 129, CZ165 21 Prague 6-Suchdol, Czech Republic
This paper deals with determining the amount of external friction angle of barley malt and malt crush depending on the load size. Barley malt is a basic raw material for production of the traditional Czech Pilsner type of beer. The angle of internal and external friction is one of the basic parameters of bulk materials. Friction among individual grains of material, i.e. a connection with the forces, applied between individual material particles, includes the internal friction angle. Conversely, the external friction angle is the angle in which the bulk material begins to move on the other material (steel). A two-roll mill (or disc mill and hammer mill) was used for the malt crush manufacture, which is used in the traditional malt processing in beer production. During crushing on this machine, we used the passage of the milled material through a gap between two counter-rotating cylinders. The results of barley malt and malt crush external friction angle, depending on the load size of the barley malt and the malt crush on mobile prototype device, are from 8 to 22°. The mobile prototype device is based on the following principle: a square chamber filled with a loaded material moves on the pad (steel).