How does a concrete batching plant work?
Batching plant is a process whereby cement is mixed with coarse aggregate (graded crush) and fine aggregate (sand particularly pit sand) as well as with water. Concrete batch plants are devices used to mix the various ingredients to form concrete. The commonly used plants in markets are ready mix plants and central mix plants and some of them use computer aided control to assist their functioning. This depends on the type of the batching plant. Some concrete batch plants are mobile while others are rather massive that they cannot be easily mobilized. If you are asking yourself ‘how does concrete batch plant works?’, then read on to get to know.
The concrete batch plants can be categorized into 4 parts: aggregate feeding, powder feeding (fly ash, cement and expanding agent), water and admixture for mixing the materials, conveyance and storage. When the control system of mixer is connected to an electricity source, the operation interface of the man-machine interaction will appear and system will begin to process initialization which includes the formula number, concrete slump, concrete grade and productivity. Each silo and weighing hopper is tested according to weighing system. Its control system will output the signal of the amount of material to prompt the operator to decide whether to start the control program or not.
The belt conveyor is initiated to transmit the aggregate to the weighing hopper; the valve of the fly ash and cement tank should be opened and the screw conveyor and motor initiated to transmit them into the weighing hopper; the control valve of the water sump and admixture sump needs to be opened to make water and admixture flow into the weighing hopper. Once the weight of all material types meets the needs of specific amounts, the door of the weighing hopper is opened automatically. The materials will then be mixed by a concrete mixer. Once the setting time is over, the loading door of the concrete mixer opens and the concrete flows into a concrete mixer truck.
This process is conducted very carefully since concrete must not segregate and also because the concrete must be ready and transported and then used before its preliminary setting time which is between 30-45 minutes. The selection of the equipment used is dependent on the scale of the project to be undertaken. In some countries, this is carried out by a mobile concrete batching plant .
A more sophisticated version of the machine is the tetra-decagonal egg-shaped mixer which does 30-60 rpm. For large scale projects, this is employed using an Archimedes’screw that hoists the ingredients, mixing them and then conveying them to the mixer. At times, the batching machine may be secured onto the truck that carries the raw materials and when they arrive at the site, the plant equipment mixes the concrete on-site. The equipment is composed of a tube, pentagonal to octagonal-shaped inside. At times, iron balls are thrown inside to assist in mixing.