Volumetric mixers have been in use since the 1960s mostly in the North American market and the design of the mixers has not changed much since the original concept. In the mid 1980s more manufactures began to produce mixers, however they are all based on the original concept and have not really advanced in terms of design and efficiency.
Most volumetric concrete mixers work on the same principle, where they introduce a fixed rate of cement and reduce the flow of aggregate if a stronger mix is required. Consequently, for concrete with higher cement content the production rate is considerably slower. To fix the cement rate they determine a relationship with the conveyor using a number of chains and sprockets. In effect this creates a "bottleneck" and slows the process down.
At NUROCK we felt this was an archaic method and developed an improved system, which has resulted in a patent.
We established a relationship between our aggregate and cement using a hydraulic system to eliminate the "bottleneck". This allows an increase in the cement content of the mix by increasing the input of cement not by reducing aggregates. As no proportion is fixed or reduced, all ingredients run at their optimum speed, thus the NUROCK system delivers faster at higher cement contents.
NUROCK mixers provide an energy efficient system that has less mechanical parts and superior output at higher strength concrete production.