Vacuum evacuation apparatus

Abstract

The present invention relates to a vacuum evacuation apparatus which can be mounted in a posture that can freely be selected a vacuum evacuation apparatus for evacuating a container from an atmospheric pressure to a high vacuum or less includes a first vacuum pump for evacuating the container to a high vacuum or less, and a second vacuum pump for evacuating the container from an atmospheric pressure to a medium or low vacuum the first vacuum pump and the second vacuum pump are integrally connected to each other into an integral unit.

What is claimed is: 
     
         1 . A vacuum evacuation apparatus for evacuating a container from an atmospheric pressure to a high vacuum or less, comprising:
 a first vacuum pump for evacuating the container to a high vacuum or less; and   a second vacuum pump for evacuating the container from an atmospheric pressure to a medium or low vacuum;   wherein said first vacuum pump and said second vacuum pump are integrally connected to each other into an integral unit.   
     
     
         2 . A vacuum evacuation apparatus according to  claim 1 , wherein said first vacuum pump has a rotational shaft and said second vacuum pump has a rotational shaft, and said rotational shaft of said first vacuum pump and said rotational shaft of said second vacuum pump have respective axes which are perpendicular to each other. 
     
     
         3 . A vacuum evacuation apparatus according to  claim 1 , wherein said first vacuum pump has a rotational shaft and said second vacuum pump has a rotational shaft, and said rotational shaft of said first vacuum pump and said rotational shaft of said second vacuum pump are rotatably supported by one of self-lubricating bearings, bearings having a semi-solid lubricant or a solid lubricant therein, gas bearings, and magnetic bearings; and
 wherein said rotational shaft of said first vacuum pump and said rotational shaft of said second vacuum pump are rotatable regardless of directions in which said first vacuum pump and said vacuum pump are installed.   
     
     
         4 . A vacuum evacuation apparatus according to  claim 1 , wherein said first vacuum pump has a bottom component and said second vacuum pump has a casing, and said bottom component and said casing are integrally connected to each other, thereby integrally connecting said first vacuum pump and said second vacuum pump. 
     
     
         5 . A vacuum evacuation apparatus according to  claim 1 , wherein said first vacuum pump and said second vacuum pump are integrally connected to each other through a heat insulation member or a small area of contact. 
     
     
         6 . A vacuum evacuation apparatus according to  claim 1 , wherein said first vacuum pump and said second vacuum pump are integrally connected to each other through a vibro-isolating mechanism. 
     
     
         7 . A vacuum evacuation apparatus according to  claim 1 , wherein said first vacuum pump has an outlet port and said second vacuum pump has an inlet port, and said outlet port and said inlet port are interconnected by an evacuation passage component comprising a vibro-isolating material. 
     
     
         8 . A vacuum evacuation apparatus according to  claim 1 , wherein said first vacuum pump has an inlet port and said second vacuum pump has an inlet port, and said inlet port of said first vacuum pump and said inlet port of said second vacuum pump are interconnected by a bypass passage for bypassing said first vacuum pump. 
     
     
         9 . A vacuum evacuation apparatus according to  claim 1 , wherein said first vacuum pump has an outlet port and said second vacuum pump has an inlet port, and said outlet port and said inlet port are interconnected by an evacuation passage component incorporating therein a check valve for preventing a fluid from flowing back from said second vacuum pump to said first vacuum pump while said first vacuum pump is in operation. 
     
     
         10 . A vacuum evacuation apparatus according to  claim 1 , further comprising:
 a controller for controlling said first vacuum pump and said second vacuum pump;   wherein said controller is integrally connected to said first vacuum pump or is installed separately from said first vacuum pump.   
     
     
         11 . A vacuum evacuation apparatus according to  claim 10 , wherein when each of said first vacuum pump and said second vacuum pump reaches a rated rotational speed and no gas is introduced into the container, said controller lowers a voltage applied to a motor of at least one of said first vacuum pump and said second vacuum pump and continuously operates said motor at a motor maximum efficient point. 
     
     
         12 . A vacuum evacuation apparatus according to  claim 10 , wherein said controller is capable of controlling the pressure in the container at a target pressure level by individually controlling respective rotational speeds of said first vacuum pump and said second vacuum pump depending on flow rates of the gas evacuated therefrom. 
     
     
         13 . A vacuum evacuation apparatus according to  claim 1 , wherein said first vacuum pump comprises a turbomolecular pump, and said second vacuum pump comprises a dry vacuum pump. 
     
     
         14 . A vacuum evacuation apparatus according to  claim 1 , wherein said second vacuum pump comprises a dry vacuum pump having a pair of pump rotors with respective magnet rotors mounted thereon, said magnet rotors have equal numbers of magnetic poles and are disposed so that their different magnetic poles are magnetically attracted to each other, and currents supplied to a multiphase armature including an iron core and a plurality of windings disposed radially outwardly of at least one of said magnet rotors are switched to actuate said at least one of said magnet rotors for thereby rotating said pump rotors in opposite directions in synchronism with each other. 
     
     
         15 . A vacuum evacuation apparatus according to  claim 1 , wherein one of said first vacuum pump and said second vacuum pump comprises a single vacuum pump and the other of said first vacuum pump and said second vacuum pump comprises either a single vacuum pump or a plurality of vacuum pumps. 
     
     
         16 . A vacuum evacuation apparatus according to  claim 15 , wherein said first vacuum pump and said second vacuum pump are integrally connected to each other by at least one evacuation passage. 
     
     
         17 . A vacuum evacuation apparatus according to  claim 1 , wherein the ratio of an axial dimension of said second vacuum pump and an axial dimension, which is assumed to be 1, of said first vacuum pump is in a range from 1 to 0.6, and the ratio of a volume of said second vacuum pump and a volume, which is assumed to be 1, of said first vacuum pump is in a range from 0.3 to 0.5.