Vacuum pump

Abstract

A vacuum pump may include a tubular stator located between an intake plate and a back plate. Mating portions on the intake plate and back plate may be used to properly locate the stator. The stator may include two internal pump chambers separated by a divider plate. The divider plate may be located within an internal cavity of the stator. A rotor in each chamber may include vanes and may be offset from the center of the chamber. Each rotor may be fixed to a rotatable shaft for operation of the vacuum pump. In some embodiments, the divider plate may have a fluid passageway extending therethrough. The fluid passageway may be located within the area swept by the rotors. In some embodiments, an exhaust outlet may include a flutter valve having a shaped surface that prevents the flutter valve from fully closing.

1 ) A vacuum pump comprising: 
 a stator having an internal cavity;    a rotatable shaft, at least a portion of the rotatable shaft oriented within the internal cavity of said stator;    a divider plate located within the internal cavity of the stator, the divider plate dividing at least a portion of the internal cavity of the stator into a first pump chamber and a second pump chamber;    a first rotor oriented within said first pump chamber, the first rotor coupled to and rotatable with said rotatable shaft;    a second rotor oriented within said second pump chamber, the second rotor coupled to and rotatable with said rotatable shaft;    wherein the divider plate further comprises a fluid passageway extending therethrough.    
   
   
       2 ) The vacuum pump of  claim 1 , wherein at least a portion of the fluid passageway extends at a non-zero angle to a longitudinal axis of the stator.  
   
   
       3 ) The vacuum pump of  claim 2 , wherein at least a portion of the fluid passageway extends in a helical direction with respect to the longitudinal axis of the stator.  
   
   
       4 ) The vacuum pump of  claim 1 , wherein the fluid passageway comprises a first portion, a second portion and a third portion, wherein the second portion comprises a cylindrical bore through the divider plate.  
   
   
       5 ) The vacuum pump of  claim 4 , wherein the rotatable shaft passes through the second portion of the fluid passageway.  
   
   
       6 ) The vacuum pump of  claim 4 , wherein a longitudinal axis of the second portion is parallel to a longitudinal axis of the stator.  
   
   
       7 ) The vacuum pump of  claim 4 , wherein the first portion of the fluid passageway comprises a volume of space extending from a first side of the divider plate through less than half the thickness of the divider plate, the first portion being in fluid communication with the second portion.  
   
   
       8 ) The vacuum pump of  claim 7 , wherein the third portion of the fluid passageway comprises a volume of space extending from a second side of the divider plate through less than half the thickness of the divider plate, the third portion being in fluid communication with the second portion.  
   
   
       9 ) The vacuum pump of  claim 1 , wherein the divider plate further comprises a groove running about the periphery of the divider plate.  
   
   
       10 ) The vacuum pump of  claim 9 , further comprising a sealing member oriented within the groove.  
   
   
       11 ) The vacuum pump of  claim 1 , wherein an outer periphery of the divider plate comprises a circle.  
   
   
       12 ) The vacuum pump of  claim 11 , wherein an outer periphery of the internal cavity of the stator comprises a cylindrical shape.  
   
   
       13 ) A vacuum pump comprising: 
 a first pump chamber;    a first rotor oriented within said first pump chamber, the first rotor coupled to and rotatable with a rotatable shaft;    a second pump chamber;    a second rotor oriented within said second pump chamber, the second rotor coupled to and rotatable with said rotatable shaft; and    a divider plate oriented between the first rotor and the second rotor, the divider plate further comprising a fluid passageway extending therethrough;    wherein the first rotor, during operation of the pump, defines a swept area having an outer periphery, the swept area oriented orthogonally to a longitudinal axis of said rotatable shaft;    wherein the entire fluid passageway of the divider plate is located within the bounds of the swept area when the swept area is projected onto the divider plate.    
   
   
       14 ) The vacuum pump of  claim 13 , wherein the first rotor further comprises at least one vane, and the swept area includes the area swept by the vane.  
   
   
       15 ) The vacuum pump of  claim 13 , further comprising a tubular stator having an internal cavity, wherein the divider plate is located within the internal cavity and divides the internal cavity into said first pump chamber and said second pump chamber.  
   
   
       16 ) The vacuum pump of  claim 15 , wherein the fluid passageway of the divider plate comprises multiple portions, each portion having a longitudinal axis, the longitudinal axis of at least one portion being nonparallel to the longitudinal axis of said rotatable shaft.  
   
   
       17 ) The vacuum pump of  claim 16 , wherein the divider plate fluid passageway comprises a first portion, a second portion and a third portion, the second portion extending in a helical direction about a central axis of the divider plate.  
   
   
       18 ) The vacuum pump of  claim 17 , wherein the first portion has a longitudinal axis oriented in a circumferential direction.  
   
   
       19 ) The vacuum pump of  claim 18 , wherein the first portion extends from a first side of the divider plate through half of the thickness of the divider plate.  
   
   
       20 ) The vacuum pump of  claim 17 , wherein the third portion has a longitudinal axis oriented in a circumferential direction.  
   
   
       21 ) The vacuum pump of  claim 20 , wherein the third portion extends from a second side of the divider plate through half of the thickness of the divider plate.  
   
   
       22 ) A vacuum pump comprising: 
 a stator having an internal cavity, the internal cavity comprising a first pump chamber and a second pump chamber;    a rotatable shaft, at least a portion of the rotatable shaft oriented within the internal cavity of said stator;    a first rotor oriented within said first pump chamber, the first rotor coupled to and rotatable with said rotatable shaft;    a second rotor oriented within said second pump chamber, the second rotor coupled to and rotatable with said rotatable shaft;    an inlet aperture in fluid communication with said first pump chamber;    an exhaust outlet in fluid communication with the second pump chamber; and    a flutter valve arranged to influence the flow of fluid through the exhaust outlet, the flutter valve comprising a flutter plate overlaying the exhaust outlet, the flutter plate having a shaped surface that prevents the flutter valve from fully closing.    
   
   
       23 ) The vacuum pump of  claim 22 , wherein the shaped surface of the flutter plate comprises a dimple.  
   
   
       24 ) The vacuum pump of  claim 23 , wherein the flutter valve further comprises a fastener for securing the flutter plate to the vacuum pump, the fastener located across the exhaust outlet from the dimple.