An aerator and an associated method and system are provided. The aerator includes an elongate body having a central bore that extends between proximal and distal ends of the body, and a plurality of channels formed in an outer surface of the body, the plurality of channels extending between the proximal and distal ends, and including at least two bends along their lengths. The bends in the channels help to provide a smoother flow of liquids passing through the aerator.

An injecting machine includes an injection cylinder, a plunger, a plunger moving mechanism, and a mixing mechanism. The plunger is reciprocally received in the injection cylinder for moving between an advanced position and a retracted position, with the injecting a liquid mixture of two different liquid materials as the plunger moves to the advanced position. The plunger moving mechanism causes the plunger to move between the advanced position and the retracted position. The mixing mechanism is disposed on the injection cylinder for mixing the two different liquid materials together to feed the liquid mixture into the injection cylinder. The plunger includes a front portion having a helical groove formed on an outer circumferential surface thereof to allow the liquid mixture fed from the mixing mechanism to pass through the helical groove for collecting in a forward space formed forward of the front portion of the plunger.