Abstract: A combined plug and sealing ring for a sprinkler nozzle includes a nozzle plug having a substantially cylindrical portion adapted to engage within a nozzle orifice of a sprinkler nozzle, and a cap overlaying the substantially cylindrical portion. A sealing ring is adapted to seat onto a threaded pipe fitting portion of the sprinkler nozzle. A leash interconnects the nozzle plug and the sealing ring. A combined plug and sealing ring in combination with a sprinkler nozzle, and a method of installing a sprinkler nozzle in a highly corrosive or extremely corrosive environment are also disclosed.

Abstract: An electric chuck includes a base, a fixed disk fixed under the base, a moving disk between the base and the fixed disk, and clamping jaws; a rotating shaft with outer threads is arranged under the fixed disk; the moving disk has a middle hole, through which the rotating shaft is threadedly passed; the clamping jaws is connected to the fixed disk and the moving disk in a movable manner; an electric motor is provided whose power is transmitted to rotate the rotating shaft; the clamping jaws will be moved to an inwardly pivoted position to hold a work piece positioned on the fixed disk when the rotating shaft is rotated to move the moving disk to its lower position; the clamping jaws will be moved to an outwardly pivoted position to release the work piece when the shaft is rotated to move the moving disk to it upper position.