Pulsation system for extn. column etc. - using piston reciprocating in cylinder without touching cylinder bore, so energy consumption is very low

The system includes a piston, which is reciprocated in a cylinder. The piston has no sealing rings, so an annular gap exists between the periphery of the piston and the bore of the cylinder. When the piston is stationary, the pressure on both its surfaces is equal. This equalisation is pref. achieved by connecting one end of the cylinder to a chamber filled with a pressurised gas. The piston is pref. reciprocated in guides so it cannot touch the bore of the cylinder. In a pref. alternative design, a hollow piston is used with a one-way gas valve. Used where one liq. phase is used to dissolve a substance present in another phase, which may be a solid, liq. or gas. An inexpensive system with low energy consumption due to the absence of friction between the piston and the cylinder. DANS UNE COLONNE PULSEE PAR LE MOYEN D'UN SYSTEME CYLINDRE-PISTON A MOUVEMENT ALTERNATIF, L'ON NE FAIT COMPORTER AU PISTON 12 AUCUN JOINT D'ETANCHEITE A L'INTERIEUR DE SON CYLINDRE 11 DE SORTE QUE LES PRESSIONS MOYENNES S'EQUILIBRENT ENTRE LE BAS DE LA COLONNE 1 ET UNE CHAMBRE A GAZ 20 ASSOCIEE AU SYSTEME POUR EQUILIBRER LA CHARGE HYDROSTATIQUE APPARAISSANT DANS LA COLONNE, CE QUI, EN COMBINAISON AVEC L'ABSENCE DE FROTTEMENTS DANS LE CYLINDRE, REDUIT CONSIDERABLEMENT LES PERTES DE PUISSANCE ET EVITE LES SORTIES DE LIQUIDE OU LES RENTREES DE GAZ.