Patent ID: 7341042

Claim:
A rotary positive displacement control system and apparatus, comprising a transmission assembly, a compression assembly, a buffer assembly and an expansion assembly, wherein the transmission assembly includes a axial base, a plurality of transmission members pivotally mounted on the axial base and gearing with each other, and a plurality of transmission shafts for carrying the transmission members; the compression assembly including a sealing first chamber which defines a compression chamber therein and has an intake port communicating with the compression chamber for taking air in, multiple compression rotors pivotally mounted to the transmission shafts and accommodated in the compression chamber, the compression rotors intermeshing with each other, each of the compression rotor having at least one lobe, and a first intake slot and a second intake slot respectively disposed on opposite sides of the first chamber, wherein the first intake slot is corresponding to an initial seal zone where the compression rotors initially intermesh with each other; the buffer assembly disposed between the compression assembly and the expansion assembly and having a base and a buffer chamber corresponding to the second intake slot; the expansion assembly including a sealing second chamber which defines an expansion chamber therein and having an exhaust port communicating with the expansion chamber for discharging air, a first exhaust slot disposed thereon and corresponding to the buffer chamber, multiple expansion rotors pivotally mounted to the transmission shafts and accommodated in the expansion chamber, the expansion rotors intermeshing with each other, each of the expansion rotor having at least one lobe, the compression and expansion rotors are identical in shape and number of the lobes, of which number can be 3, 4 or 5, or number of the lobes of the compression rotor differs from that of the expansion rotor, the lobe disposed in counter direction to the lobe of the compression rotors and having a concavity corresponding to the first exhaust slot, and a second exhaust slot disposed on the sealing second chamber and corresponding to a ultimate seal zone where the compression rotors ultimately intermesh with each other.