Liquid product is pumped at a constant flow rate through an injection tee or eductor. The nitrogen or filtered air, which has been regulated to a constant pressure, flows through a constant flow valve that controls the flow to the proper rate for the product. The gas enters the tee or eductor and the two streams are mixed. In-line static or dynamic (WCB CR Mixer) mixers may be used to insure proper mixing. The product then goes to filling or further processing. An eductor is used when the injection gas is not available at a pressure higher than the product backpressure.

An eductor is a static device, also known as a “jet pump”, that uses the venturi effect to pull a low pressure stream (the gas) into a high pressure stream (the liquid product).