MODEL AT3
5 – 2
APPLICATION AFTER DISSOLVED AIR FLOTATION (OAF) EQUIPMENT
Dissolved air flotation devices such as Wemcos Introduce a considerable amount of entrained air to the
process stream. These bubbles of entrained air will reflect acoustic energy In the same way a particle or
oil droplet will. To obtain a reliable reading after a DAF, it is necessary to remove this entrained air from
the process stream. This can be done with a simple stilling well such as the one shown in Figure 5-1.
Figure 5-1: Dissolved Air Flotation Equipment Installation
The idea of the stilling well is to allow air to escape through the vent in the stilling well's top while drawing
your de-aerated sample from the stilling well's bottom. It is important to include a valve on the Inlet to
your stilling well to allow you to regulate flow and to maintain a pocket of air between the liquid level and
the vent. Likewise, a valve after the sensor in the effluent stream is useful to assure that you will always
have a full line at the sensing point. The stilling well dimensions are not critical, and those shown in
Figure 5-1 should only be used as guidelines. A 3 foot section of 10 to 12 inch diameter stainless steel
pipe makes a fine stilling well body. Also, in most cases, PVC will work as well as stainless steel.
Summary of Contents for Monitek AT3
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