S.A. Armstrong Limited: air separator brochure
Information on the company’s Vortex Air Separator is detailed in this brochure. The product is designed to eliminate entrained air from heating and cooling systems, therefore designed to result in better overall performance and low operating costs. According to the company, circulation through the air separator creates a vortex (or whirlpool) action, sending the heavier air-free water to the outer portion of the tank allowing the lighter air-entrained water mixture to lower velocity center. Here it collects and exits through an air vent or compression tank installed above, it says.
— S.A. Armstrong Limited