Patent ID: 8524146

Claim:
A rotary degasser for introducing gas into molten metal, the rotary degasser comprising: an impeller shaft, the impeller shaft comprising a gas-transfer conduit and having a first end that includes one or more grooves and is not threaded, and a second end; a coupling coupled to the first end of the impeller shaft and including a plurality of retainers, each retainer having a first end received in one of the one or more grooves in order to retain the first end of the impeller shaft; an impeller connected to the second end of the impeller shaft, wherein the impeller comprises: at least one impeller opening communicating with the gas-transfer conduit; at least one open channel juxtaposed the opening; at least one cavity comprising top surface and at least one curved impeller side surface and the at least one of the channels is in communication with the curved impeller side surface; and wherein the at least one channel guides gas exiting the opening to the at least one cavity of the impeller.