| 摘要 |
Counterthrust Seal For A Rotary Fluid Machine Rotary fluid machines such as gas compressors generally comprise a housing containing a duct and a rotor which rotates within the duct. The rotor includes at least one impeller which contacts the fluid passing through the duct. Axial forces are imposed on the rotor by the fluid due to the momentum of the fluid and the pressure differentials within the duct. This invention provides a counterthrust seal assembly disposed between the rotor and the housing to inhibit the escape of fluid out of the duct at the point where the rotor passes through the housing and is operable to apply a variable force to the rotor to counteract the axial forces due to the fluid passing through the duct. The counterthrust seal assembly is formed from three fluid seals assembled in series wherein the seals have different effective sealing diameters. A first and second piston chamber are formed between the seals due to the difference in effective sealing diameters. By modulating the pressure within the piston chambers the magnitude and axial direction of the force applied to the rotor by the counterthrust seal assembly can be varied. |
