Gas and chemical infusers use water or other liquids as the motive fluid, and operate on the venturi principle to inject gases or other liquids into a pressurized liquid stream. These gas infusers allow maximum gas or liquid injection with minimal differential pressure. Liquid is pumped through the infuser nozzle, emerging at a relatively high velocity, creating a zone of lower pressure contained within the suction chamber of the infuser. The suction fluid is drawn to this lower pressure zone, where the momentum of the motive liquid is transferred to the suction fluid, causing the suction fluid to be pumped.