Dosing tasks, according to a defined formulation of liquid and/or solid substances, are often performed on balances. In this context the formulations are usually generated from databases either statically (fixed formulation) or dynamically (formula-based formulation).
The European patent EP 1 975 577 A1 discloses a balance that is designed for the gravimetric calibration of pipettes and that has a draft shield and built-in temperature, air pressure and air humidity sensors.
The German patent DE 44 07 433 C2 discloses a balance for dosing. In the event of an incorrect dosage of the individual constituents this balance can be used to make a correction of the dosing of the rest of the constituents within a formulation. The drawback is that during dosage of the individual constituents, only the percentage by mass of the individual constituents is considered.
Even in the case of a dynamic formulation, however, the current ambient conditions (temperature, humidity, time, . . . ) are not considered at the location and time of the dosing process, so that the formulation may not meet the requirements of the subsequent application.
One example of this effect of the ambient conditions are mixtures of volatile constituents, the proportion of which varies in the subsequent processing steps, as a function of the evaporation rate, which prevails at the weighing location and which is largely determined by the air temperature and the air humidity. It affects, for example, liquid mixtures that contain alcohol. On the other hand, during dosage of hygroscopic substances as a constituent of a formulation, the effect of the climate parameters, for example, is important, in particular, the effect of the air temperature and the humidity.
Another example are mixtures having a viscosity that depends on the ambient temperature and in subsequent process steps should have a specified target value, for example, baking mixes with variable fat or water content. In this case it would be desirable for the formulation to be corrected according to the current and local ambient conditions, with the result that the viscosity value meets the requirements for the kneading or molding processes.
In addition, the ambient conditions in the subsequent processing steps affect the end results. For example, the ambient humidity affects paint mixtures that are sprayed, because the drying process and the curing process run at different speeds due to the ambient humidity. If in this case the objective is to achieve the same application quality, irrespective of the ambient humidity, then a suitably adjusted amount of solvent would be necessary.