A portable, rotating vane vacuum pump with an automatic vacuum breaking arrangement, said portable vacuum pump including:
- a housing having an inner surface with at least a portion thereof extending about a first axis and defining in part a bore,
- a rotor mounted within said bore for rotation about a second axis offset from and substantially parallel to said first axis, said rotor further including at least two vanes mounted for sliding movement within respective slots in said rotor, a motor to selectively rotate said rotor in a first rotational direction about said second axis within said bore, said vanes having inner and outer edge portions with the outer edge portions being in contact with the inner surface of said housing as said rotor is rotated by said motor about said second axis within said bore separating said bore into a plurality of chambers with at least one of said chambers being at a pressure less than ambient pressure,
- said housing further including at least one inlet passage and at least one outlet passage through said inner surface in respective fluid communication with said bore,
- a lubricating oil system having an oil inlet arrangement and an oil return arrangement, said oil inlet arrangement including a primary oil reservoir container, a secondary oil reservoir container, and a pump mechanism between said primary and secondary containers to move oil from the primary container to the secondary container with said primary and secondary containers open to atmosphere and at ambient pressure, said oil inlet arrangement supplying oil from said primary container and downstream of said pump mechanism to the bore of said housing into said at least one chamber while the motor is rotating said rotor and said primary and secondary containers are open to atmosphere and at ambient pressure, said one chamber being at said pressure less than ambient pressure and said oil being drawn into said one chamber via a first path downstream of said pump mechanism while said motor is rotating said rotor and said primary and secondary containers are open to atmosphere and at ambient pressure, said first path being in fluid communication with said secondary container and,
- said oil return arrangement delivering oil via a second path from the bore of the housing and said secondary container back to said primary container with said primary and secondary containers open to atmosphere and at ambient pressure, said primary container forming at least a portion of a sump for said oil being delivered back by said return arrangement from the bore of said housing and said secondary container wherein substantially all of the oil in said portable vane pump including in the lubricating oil system thereof is contained in said primary container and wherein said secondary container contains only a relatively small fraction of the volume of the oil in the primary container while said motor is rotating the rotor and said primary and secondary containers are open to atmosphere and at ambient pressure, and
- an automatic vacuum breaking arrangement to vent the bore of the housing to atmosphere upon the motor ceasing to rotate the rotor, said automatic vacuum breaking arrangement including said secondary container open to atmosphere and said first flow container and with the bore of said housing wherein ambient air enters the bore of said housing via the secondary container and said first flow path.