Residence time and level control in a separator

[Lonelywish]

I'm currently designing a separator which is used to remove excess air from saturated water after passing through a saturation tank. From thread124-155681 i saw some information that is usefull for my design but I'm not too sure about the level controller design.
1)How do I know at which point should I open my valve to release my air and to release my water flow into the next tank?
2)If my valve is opened at 100%, what will happen to the pressure in the tank? Will the pressure drop be too great that the flow into the tank will increase and cause a huge increase of water depth in the tank?
3)Is there any other safety limitations that I need to consider?
Hope someone is able to help.
Alex

 

[bimr]

The air saturator tank is maintained under the same pressure as the water. There are various ways to accomplish this. Use an pressure reducing valve on the air supply to reduce the air pressure to the same pressure as the water. Air is introduced at 50-60 psig at the top of the saturator tank where a layer of air is maintained.

Water enter the saturator tank from the top through a spray nozzle and exits the bottom of the saturator tank. A level controller maintains the water level in the tank.

Exiting water leaves the tank pressurized. As the discharged water flows through the discharge piping, the water will flow through a valve, that will release the water pressure as well as the saturated air that is in the water.

This type of air saturator is used for DAF systems:

http://www.acssb.com.my/httpdocs/pdf/ACEM.pdf