ring 56 permits the flexibility reversing of the device in driving it in either clockwise or counter clockwise direction features contributing to the efficiency of this invention reside in the multiple bearing means in association with the vane retainers 21 central shaft 24 and bushing 25 as well as the improved sealing means of the system one feature of this improved sealing means is embodied in the vane bearing 18 and vane bearing inserts 19 in addition to the foregoing structures an improved sealing combination is incorporated in rotor sealing ring 70 and retainer 71 encircling each end of the rotor 16 as is illustrated in fig1 and fig4 in detail in fragmented enlarging view of fig1 and fig1 this rotor sealer ring 70 encircles rotor 16 at the exterior contact points of shaft face plate 27 and exhaust face plate 28 fig1 and 15 rotor sealing rings 70 are held in position by rotor sealing ring retainer 71 which is affixed to shaft face plate 27 or exhaust face plate 28 fig1 and 15 by means of series of retainer screws 72 to insure the efficiency of this seal an arcuate or curved rotor sealing ring spring 73 is employed this insures a flexible firm contact between rotor 16 and the face plates 27 28 an improvement incorporated in the preferred embodiment resides in the vane edge sealing means illustrated in fig1 through 24 these improved vanes and seals are constructed by machining vane wiper edge slots 74 in the vanes 17 dimensions are relatively optional however in the preferred embodiment these slots were 1.