Abstract: A vacuum pump assembly has a conventional electric motor, a mounting plate centered with respect to the drive shaft of the motor, and a self-contained, replaceable modular pumping apparatus. The module has a stator, a rotor, and axially opposite end plates enclosing a pumping chamber, and is detached easily, quickly mounted onto the mounting plate as a unitary assembly, and operatively connected to the drive shaft of the motor by a shock-absorbing self-aligning coupling. It is enclosed by a pump housing containing lubricant for lubrication and sealing purposes during pump operation. The pumping module has a double seal to maintain lubricant and to allow the shaft connected to the rotor to center itself relative to the mounting plate and the motor.

Abstract: A vacuum pump, having a pumping chamber with intake and exhaust ports communicating therewith, is provided with an arrangement to insert a liquid lubricant into the pumping chamber. A sensing device is utilized to detect the pressure at the exhaust port, the sensing device permitting operation of a deactivating unit when the pressure at the exhaust port falls below a predetermined value, pressure below the predetermined value being indicative of improper pumping action in the pump. The deactivating unit acts to render inoperative the lubricant introducing arrangement when the sensing device detects a pressure at the exhaust port below the predetermined value, thus precluding the insertion of lubricant into the pumping chamber upon the occurrence of defective pumping action in the vacuum pump.