Abstract: The roller-vane hydraulic machine comprises a hollow casing (1) having working fluid inlet and outlet passages (2, 3). The casing (1) is provided with hollows opening into the space of the casing (1), said hollows accommodating rollers (4) interacting with a rotor (5) located inside of the casing (1). The casing (1) is provided with vanes (6) which, together with the casing (1) form a working space (7) divided by the rollers (4) into larger and smaller inter-roller chambers (8, 9) intercommunicated in pairs by hydraulic relief passages (14, 15). The rollers (4) have slots for the passage of the vanes (6) of the rotor (5). The larger and smaller inter-roller chambers (8, 9) are intercommunicated in pairs by passages (14, 15, 16, 17) in the casing (1).

Abstract: A flow meter has a rotor with vanes. The rotor is mounted with sealing clearances in a casing and defines therewith a working space. The casing has fluid admission and discharge ports and recesses for accommodation of rollers. Peripheries of the rollers define with the recess surfaces and with the rotor surface other sealing clearances dividing the working space into fluid admission and discharge chambers. The rollers are made with grooves for the rotor vanes to pass therethrough. Each recess has pockets, and a sealing land is defined between the pockets. The valve of any sealing clearance ranges from 0.0005 to 0.0002 times the roller diameter.