A mixing device for creating an output mixture by mixing a first material and a second material, the device comprising: a first chamber configured to receive the first material from a source of the first material; a stator; a rotor having an axis of rotation, the rotor being disposed inside the stator and configured to rotate about the axis of rotation therein, at least one of the rotor and stator having a plurality of through-holes; a continuous arcuate mixing chamber defined between two contoured surfaces (606 and 706) of the rotor and the stator, the mixing chamber having an open first end portion in fluid communication with the first chamber and configured to receive the first material therefrom, and the second material being provided to the continuous mixing chamber via the plurality of through-holes formed in the at least one of the rotor and stator wherein the rotor is suitable to impart a mixing circumferential velocity into the first material and the second material inside the continuous mixing chamber; and a first internal pump housed inside the first chamber, the first internal pump being configured to pump the first material from the first chamber into the mixing chamber and to impart a circumferential velocity into the first material before and as it enters the continuous mixing chamber, wherein the circumferential velocity imparted into the first material by the first internal pump approximates the mixing circumferential velocity imparted by the rotor, and wherein the first material does not negotiate any corners or bends between the first chamber and the mixing chamber, such that the first material inside the first chamber may flow freely into the open first end portion of the mixing chamber. a first chamber configured to receive the first material from a source of the first material; a stator; a rotor having an axis of rotation, the rotor being disposed inside the stator and configured to rotate about the axis of rotation therein, at least one of the rotor and stator having a plurality of through-holes; a continuous arcuate mixing chamber defined between two contoured surfaces (606 and 706) of the rotor and the stator, the mixing chamber having an open first end portion in fluid communication with the first chamber and configured to receive the first material therefrom, and the second material being provided to the continuous mixing chamber via the plurality of through-holes formed in the at least one of the rotor and stator wherein the rotor is suitable to impart a mixing circumferential velocity into the first material and the second material inside the continuous mixing chamber; and a first internal pump housed inside the first chamber, the first internal pump being configured to pump the first material from the first chamber into the mixing chamber and to impart a circumferential velocity into the first material before and as it enters the continuous mixing chamber, wherein the circumferential velocity imparted into the first material by the first internal pump approximates the mixing circumferential velocity imparted by the rotor, and wherein the first material does not negotiate any corners or bends between the first chamber and the mixing chamber, such that the first material inside the first chamber may flow freely into the open first end portion of the mixing chamber.