Vacuum pumping system having an oil-lubricated vacuum pump

Abstract

A vacuum pumping system includes an oil-lubricated vacuum pump, including a stationary pump stator and a rotatable pump rotor, and a motor, including a stationary motor stator and a rotatable motor rotor cooperating with each other for driving in rotation the pump rotor. The motor further includes an oil-tight unit including a metal jacket enclosing the motor rotor and forming a container intended to collect and keep inside the motor any oil leaking from the pump.

What is claimed is: 
     
         1 . A vacuum pumping system, comprising:
 a vacuum pump, comprising a pump casing defining a stationary pump stator and housing a rotatable pump rotor, said pump stator and said pump rotor cooperating with each other for pumping a fluid from a pump inlet to a pump outlet; and   a motor, comprising a motor casing in which a stationary motor stator and a rotatable motor rotor are received, said motor stator and said motor rotor cooperating with each other for driving in rotation said pump rotor by means of a drive shaft, wherein:   said vacuum pump is an oil-lubricated vacuum pump; and   the vacuum pumping system further comprises an oil-tight unit arranged to enclose at least a portion of the motor rotor and forming at least part of a container configured to collect and keep inside the motor any oil leaking from the pump.   
     
     
         2 . The vacuum pumping system sample according to  claim 1 , wherein said unit comprises at least a portion clamped between the motor casing and the pump casing. 
     
     
         3 . The vacuum pumping system according to  claim 2 , wherein said unit comprises a substantially cylindrical jacket enclosing the whole of the motor rotor and forming said container, and wherein said jacket:
 comprises a side wall located in an air gap separating the motor rotor from the motor stator;   is open at a first end, where it is clamped between the motor casing and the pump casing; and   is closed, at a second end opposite the first end, by a base accommodated at least partly inside the motor casing.   
     
     
         4 . The vacuum pumping system according to  claim 3 , wherein the open end of said jacket has a rim that projects radially outwards and forms the portion clamped between the motor casing and the pump casing, and wherein a static seal is provided between a surface of said rim facing the pump casing and a confronting surface of the pump casing. 
     
     
         5 . The vacuum pumping system according to  claim 3 , wherein said jacket is made of sheet metal. 
     
     
         6 . The vacuum pumping system according to  claim 3 , wherein said jacket is provided, at both the first and second end, with bases having a larger diameter than the side wall and protruding radially outwards from the side wall, and wherein, in the base provided at the first, open end of the jacket, the surface turned towards the pump casing is configured so as to engage in oil-tight manner a complementarily shaped axial recess formed in the pump casing. 
     
     
         7 . The vacuum pumping system according to  claim 6 , wherein, in the radially protruding portions of said bases, the surfaces turned towards each other are shaped so as to define annular circumferential axial recesses accommodating opposite axial ends of the motor stator, and wherein each of said circumferential axial recesses is radially delimited towards the outside of the motor by an axially projecting edge located between the motor stator and the motor casing and, towards the inside of the motor, by a thickened end portion of the side wall. 
     
     
         8 . The vacuum pumping system according to  claim 6 , wherein the base provided at the second end of the jacket is wholly received inside the motor casing. 
     
     
         9 . The vacuum pumping system according to  claim 6 , wherein the surface of the base provided at the second end of the jacket turned away from the motor has a conical profile at least partially projecting outside the motor casing, and wherein said surface projecting outside the motor casing is provided with cooling fins. 
     
     
         10 . The vacuum pumping system according to  claim 6 , wherein said jacket is made of an oil-resistant, electrically insulating thermosetting or thermoplastic resin. 
     
     
         11 . The vacuum pumping system according to  claim 2 , wherein said unit comprises a first disc-shaped component and a second disc-shaped component accommodating opposite axial end portions of both the motor stator and the motor rotor and forming, together with the motor stator, the container, the first disc-shaped component forming the portion of the unit clamped between the motor casing and the pump casing, and engaging in oil-tight manner a complementarily shaped axial recess formed in the pump casing. 
     
     
         12 . The vacuum pumping system according to  claim 11 , wherein the first disc-shaped component and the second disc-shaped component have, on their faces turned towards each other, respective circumferential axial recesses accommodating opposite axial ends of the motor stator, and wherein said circumferential axial recesses are radially delimited towards the outside of the motor by a respective first annular axial projection located between the motor stator and the motor casing, and are radially delimited, towards the inside of the motor, by a respective second annular axial projection located between the motor stator and the motor rotor. 
     
     
         13 . The vacuum pumping system according to  claim 11 , wherein the second disc-shaped component is wholly received inside the motor casing. 
     
     
         14 . The vacuum pumping system according to  claim 11 , wherein the surface of the second disc-shaped component turned away from the motor has a conical profile at least partially projecting outside the motor casing, and wherein the surface of the second disc-shaped component projecting outside the motor casing is provided with cooling fins. 
     
     
         15 . The vacuum pumping system according to  claim 11 , wherein said first and second disc-shaped components are made of an oil-resistant, electrically insulating thermosetting or thermoplastic resin.