Modular vacuum pump assembly

A rotary displacement vacuum pump assembly incorporating a rotor drive motor with a motor drive shaft and comprising:

• a mounting plate, the rotor drive motor being mounted on one side of said mounting plate;
• a stator body portion with an internal cavity to provide a pumping chamber;
• a rotor having a plurality of rotor vanes located in said pumping chamber;
• a rotor shaft affixed to said rotor to mount said rotor in said pumping chamber;
• an intermediate plate to close the end of said pumping chamber adjacent said mounting plate, said intermediate plate including a bearing for said rotor shaft;
• an end plate to close the other end of said pumping chamber;
• fastening means to rigidly interconnect said intermediate plate, said stator body portion and said end plate to form an integral modular pump assembly;
• mounting means to releasably connect said modular pump assembly to said mounting plate;
• a detachable flexible coupling to connect the motor drive shaft to said rotor shaft through said mounting plate;
• a vacuum inlet conduit in said mounting plate;
• a vacuum intake conduit in said intermediate plate and said stator body portion communicating with said vacuum inlet conduit and extending into said pumping chamber;
• a gas-ballast conduit extending from atmosphere to said pumping chamber through said mounting plate, said intermediate plate and said stator body portion;
• a fluid-tight pump housing mounted on said mounting plate and surrounding said modular pump assembly;
• a discharge conduit in said stator body portion extending from said pumping chamber to the space between said pump housing and said modular pump assembly;
• a first check valve located in said discharge conduit to close said discharge conduit except when releasing pressure from said pumping chamber;
• a secondary pumping arrangement to increase pumping efficiency, the pressure created by said secondary pumping arrangement being released into said space between said pump housing and said modular pump assembly;
• a discharge vent in said pump housing to release pressure to atmosphere,
• a coupling collar rigidly connected to the drive shaft of the rotor drive motor, a pair of cruciform slots being formed in said collar;
• a pair of cruciform slits formed in the motor end of the rotor shaft;
• and
• an elastomeric crosspiece to fit into said slots of said coupling collar and said slits in the rotor shaft to provide a driving connection between the rotor drive motor and said rotor.