Abstract: The invention pertains to a lightweight and concise vaccum pump particularly suitable for servicing refrigeration systems. One end of a cylindrical electric motor casing is enclosed by a substantially cylindrical adapter upon which a pump assembly is mounted. The motor armature shaft extends through the adapter and the pump rotor is directly mounted thereon. A hollow shell affixed to the adapter encompasses the pump assembly defining a chamber thereabout which includes a lubrication sump. A synthetic plastic handle assembly attaches to the motor casing and includes a capacitor housing and a base is affixed to the lower side of the casing. Except for the handle and base the pump is of a substantially cylindrical configuration of a diameter similar to that of the motor casing, and the pump assembly includes lubrication and exhaust features which provide improved pumping conditions.

Abstract: The invention pertains to a two-stage vacuum pump for servicing refrigeration systems wherein a pair of electrically driven rotors support movable vanes engaging the cylindrical circumference of pumping chambers in which the rotors are mounted. The improvements pertain to the sealing of the rotor shaft, the introduction of metered oil into the pump, and the keying of a rotor to its driveshaft wherein improved assembly and operational characteristics are achieved.

Abstract: The invention pertains to a two stage vacuum pump particularly suitable for servicing refrigeration systems wherein a pair of electrically driven rotors support outwardly movable vanes engaging the cylindrical circumference of pumping chambers in which the rotors are mounted. The efficient relationship of components produces a high capacity pump in a concise configuration, lateral sides of the rotors are recessed to produce rapid seating of the vanes, reduce hydraulic end loading of the second stage rotor and minimize friction. The vanes are offset from the associated rotor axis to allow greater displacement for a given chamber bore and rotor size, and advantageous frictional forces are produced to augment sealing between the vane tips and chamber surface. Further, the vane tips are shaped to optimize compression and reduce gas re-expansion, and the rotors of the two stages are rotationally phased to improve capacity and pumping characteristics.