The Parker Boiler Deaerator reduces the residual oxygen level in make-up water to below 7 ppb (parts per billion) or .005 cc per liter, CO2 is virtually zero. They incorporate a number of features that make it unique on the market, more modern with fewer moving parts, simpler and easier to operate. In the tray type (DAT), as the feed water enters the tray column from the top of the dome, it cascades down a series of trays and encounters a counter flow steam vent. This counter flow action removes oxygen and carbon dioxide. In the tank of the deaerator, there is a scrubber, which continually circulates the water in the deaerator bringing it in contact with steam and causing deaeration of this water. The spray type (DAS) uses a counter flow water spray over the venting steam.