Turbo-molecular pump

Abstract

A turbo-molecular pump includes a casing having an intake port, a stator fixedly mounted in the casing, and a rotor supported in the casing for rotation relatively to the stator. The stator and the rotor make up a turbine blade pumping section and a groove pumping section for evacuating gas. A scattering prevention member is provided for preventing fragments of the rotor from being scattered through the intake port.

What is claimed is:  
     
         1 . A turbo-molecular pump comprising: 
 a casing having an intake port;    a stator fixedly mounted in said casing;    a rotor supported in said casing for rotation relatively to said stator, said stator and said rotor serving as at least one of a turbine blade pumping section and a groove pumping section for evacuating gas; and    a scattering prevention members for preventing fragments of at least one of said rotor and said stator from being scattered through said intake port.    
     
     
         2 . A turbo-molecular pump according to  claim 1 , wherein said rotor comprises rotor blades and said stator comprises stator blades, and said scattering prevention member comprises at least part of said rotor blade or said stator blade  
     
     
         3 . A turbo-molecular pump according to  claim 1 , wherein said scattering prevention member includes at least one protrusion projecting radially inwardly from an inner surface of said intake port.  
     
     
         4 . A turbo-molecular pump according to  claim 1 , wherein said scattering prevention member is made of a high-strength material.  
     
     
         5 . A turbo-molecular pump according to  claim 1 , wherein said scattering prevention member is made of a high-energy absorbing material.  
     
     
         6 . A turbo-molecular pump according to  claim 1 , wherein said scattering prevention member has a shock absorbing structure.