Système de dosage chimique proportionnel

Photo: Système de dosage chimique proportionnel

The proportional dosing system is designed for the dosing of chemicals (e.g., flocculants during the simultaneous precipitation of phosphates in wastewater) in plants that confront the issue of a variable water level depending on the incoming quantity of water. The system can also be installed in existing plants.

Equipment description

The system consists of a dosing device and a floater mechanism. The replenishment of chemicals in the dosing device (2) from the reservoir (1) is controlled by the floater (3) in response to a reduction of the quantity of chemicals during dosing. The entire dosing is designed in such a way that the floater (6), with a vertical movement, ejects from the reservoir, by means of a dosing tube (4) with adjustable height, the amount of the chemical corresponding to the length of lift of the floater (7) and floater size (6). The required quantity is adjusted through corresponding dilution of the chemical or a change of the diameter of the pipe (5) and floater (6).

Equipment installation

The equipment consists of a PP pipe with the length of about 600 mm and DN 125, which is usually attached by means of yokes to the treatment plant wall, in such a way as to ensure the undisturbed operation of the pulley and floater and to enable the appropriate interconnection of the dosing device with the chemical reservoir.

Sample application of the equipment

During the day, a certain volume of treated water Q flows into the treatment plant, to which corresponds the sum of the vertical movements of the floater positioned on level H . There is a direct relationship between Q and H. Given the above-mentioned equipment design, the amount of the required dosed chemical results from H, the dimensions of the floater (6), and the concentration. With its movement, the floater (6) ejects from the dosing device a quantity corresponding to the height H and the area of the footprint of the floater (6). The corresponding dose is then influenced by dilution. If even at the highest possible concentration the corresponding dosing cannot be achieved, the dose may be increased by increasing the size of the guide pipe (5) and floater (6).