Abstract: An apparatus for protecting vacuum sources from contamination occasioned by aspiration of fluids or aerosols from a device operated by such vacuum sources, having an enclosed vessel in communication with the device, a filter in communication with the enclosed vessel to entrap aerosols and a vacuum-breaking valve alternately in communication with atmosphere & vacuum in communication with the filter to control the application of the vacuum by the vacuum source to the device. The vacuum-breaking valve is operated by a switch assembly mounted within the enclosed vessel and in electrical communication with a solenoid designed to operate a valve member within the vacuum-breaking valve.