www.saVRee.com Deaerators Explained pg.
6
How Deaerators Work
There are two common deaerator designs, spray and tray (spray-tray). Each design has
its own operating characteristics. Regardless of the design employed, both deaerators
designs:
•
Maximize the contact surface area between the water and steam to obtain a high
heat transfer rate.
•
Rely upon direct contact between the steam and water (usually tray, spray,
bubbling, or a combination of these).
•
Employ spray nozzles.
•
Utilize steam as the heat source.
•
Agitate the water using steam.
•
Can be mounted onto the top of a feedwater storage tank.
•
Are often manufactured from the same materials.
•
Are open/vented to atmosphere.
Although spray deaerators are often mounted to the top of feedwater tanks, they can also
be installed within the feedwater tank. A deaerator mounted above a feedwater tank will
appear either as a small tank connected by a pipe to the feedwater tank, or, as a dome or
vertical column, mounted directly to the feedwater tank.
Makeup water will pass through the deaerator when it enters the system. Condensate may
or may not pass through the deaerator depending upon its condition when returned to the
feedwater tank. Deaerator designs vary because each steam system has unique
requirements.
How Tray Deaerators Work
Water enters the deaerator and fills the water box. The water box is a temporary holding
area that ensures water is fed evenly through a series of spray nozzles, then into the
deaerator.
Each spray nozzle acts as a non-return valve and will close if the water box has insufficient
water pressure. To ensure long life, spray nozzles, the surrounding spray area and the
trays, are all constructed of stainless steel.