Gas-jet steam siphons use steam as the motive fluid, and operate on the venturi principle to pump liquids or slurries. Steam is discharged through the siphon nozzle, emerging at a relatively high velocity, creating a zone of lower pressure contained within the suction chamber of the siphon. The secondary or suction fluid is drawn to this lower pressure zone, where the momentum of the motive steam is transferred to the suction liquid, causing the suction liquid to be pumped. It can also be used with compressed non-condensable gases, as the motive fluid to pump relatively very small volumes of liquids or slurries.