Types of solid and liquid dosing systems
They can be classified in two ways, depending on the way in which the measurement is carried out, they can be by weight (gravimetric) or volumetric, if we look at the type of process, they can be continuous or discontinuous (discrete).
Continuous gravimetric dosing
It is the most complex dosing process, it is generally only used for solids, for its execution it is required that the weighing equipment be dynamic, that is, the component is weighed as it is fed to the next process, which is usually mixing. Therefore the difficulty arises when designing this weighing element.
At SOTECMA, we have been developing continuous gravimetric dosing systems for more than 30 years, relying on dynamic weighing on a conveyor belt and the weighing dosing system with hopper. A utility model patented by SOTECMA more than 20 years ago and thanks to it is achieved greater precision. Due to its complexity, this type of dosage must always be carried out with an automatic control system.
We apply this type of dosage in our gravel-cement or cement soil plants, for the dosage of cement on the aggregate.
Discontinuous gravimetric dosing
It is the most used and precise dosing process since it allows us to weigh statically, thus allowing a good vein adjustment. It is easier to implement than the discontinuous one.
For any weighing system, the absence of vibrations and external actions that may interfere on the scale is essential, and more when it comes to dosing small quantities (below 10 kg), that’s why SOTECMA has developed and patented a high precision scale with a turning system for emptying and which is encapsulated to avoid the action of external agents.
In this case, the process can be carried out manually, starting and stopping the dosing equipment manually, but it is totally discouraged due to the risk of depending on the action of an operator who may forget to add a component, or repeating one or simply not stopping the dosing equipment in time by providing more of the component than required.
We apply this type of dosage in our dry mortar plants and concrete manufacturing plants, for the dosage of all the components that the mixture of this product requires.
Continuous volumetric dosing
It is used in both liquids and solids, for liquids the measurement can be quite precise in that the density is practically constant.
In the case of solids, the apparent density varies greatly depending on the granulometry and the degree of aeration of the product, and it is for this reason that this system is used only for processes where the proportion in weight of the various dosed components is not very precise.
We carry out this dosing system in our gravel-cement or soil-cement plants for dosing the water.
Discontinuous volumetric dosing
The only difference with the previous one is that the process is done in batches, but this does not mean more precision is achieved, the equipment used to measure is usually the same for both processes.