PULSATING GAS DOSAGE IN THE MOULDING SANDS HARDENING PROCESS IN THE COLD-BOX TECHNOLOGY

The results of investigations of the moulding sands hardening process in the cold-box technology – with an application of two ways of gas dosage – are presented in the paper. A new, ultrasound method of testing the kinetics of hardening of moulding sands with chemical binders was applied. Moulding sands with phenol-formaldehyde resin and moulding sands with water-glass hardened by CO2., were subjected to investigations. A continuous gas dosage was substituted by the pulsating one. It was shown, that the change of the dosage mode could lead to decreasing the gas consumption (even several times). In addition, it was found that the pulsating way of dosage provides improvements of moulding sands technological properties, mainly strength. Investigations concerned the cold-box processes, in which one or two technological gases were used