Scales and transport of material
The scales for aggregates are delivered according to the type of concrete plant. This may be a weighted aggregate loading skip, independent steel scales (lined with abrasion-resistant material and equipped with vibrator and a cradle flap) or weighted belt conveyor, whereas we distinguish 3 methods of weighing:
- Static weighted belt conveyer with side shutters. The aggregate is dosed on a stationary belt conveyer.
- Dynamically weighted belt conveyor, which is controlled by a frequency inverter in both directions. The aggregate is dosed in an even layer on a running belt conveyor. Individual fractions are placed on the belt one after another, and therefore the conveyor does not have side shutters. A great advantage of this solution is a very high accuracy of dosing (especially during frequent changing of various required quantities), while maintaining high output of the concrete plant and low operational costs.
- The patented technology of weighted Z belt conveyor of Flexowell type with side bellows and transoms, which transports the weighed aggregate in the hopper above the mixer where it is prepared instantly for discharge to the mixer. This technology increases the output of the concrete plant by up to 40%! When using a mixer with volume of 1 m³ of concrete for the batch, it is possible to reach production of up to 70 m³ of concrete per hour. Another important advantage of this technology is also the fact that the concrete plant does not have any aggregate loading skip and therefore no risk exists as regards its failure or the skip falling down.
The scales for cement, water and admixtures are made of stainless steel in the required sizes and shapes according to the type of concrete plant. Up to the weight range of 700 kg, the scales are suspended on a single point load cell; for bigger scales we use classic suspension on three load cells.
For dosing of cement we produce the centreless screw conveyors. The screw is forged with thickness 12 mm. The conveyor is maintenance free because it has no lubrication points. High output at low speed and a robust screw ensure a long lifetime of the whole system. It is suitable for dosing of cement, fly-ash, silica, stone dust. etc. The scales for cement are equipped with a V-flap and vibrator for easier discharge of material into the mixer.
Dosing of admixtures is assured by gear-pumps, which may be controlled optionally by frequency inverters for very accurate weighing, especially for very small batches. The scales are equipped with washing by clean water, which is used for the scale cleaning or for the admixture dilution. A stainless steel ball valve discharges the admixture, which flows by gravity into the mixer.