A mixer using the kinetic energy of a jet of gas issuing from an orifice to entrain all or part of the air necessary for combustion. If gas for the jet is available at the spud at gauge pressures below 6. 9 kPa (1 psi), the mixer is defined as a low-pressure atmospheric inspirator mixer; if at gauge pressure 6. 9 kPa (1 psi) or above, the mixer is designated as a high-pressure atmospheric inspirator