The risk of uneven air discharge from air diffusers.

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WARNING: Beware of the following when choosing an air diffuser—

The risk of uneven air discharge from air diffusers

Warning for users of non-OHR vertical air diffusers

Customers who use imitations of the OHR AERATOR say “Air is not discharged from some of the installed air diffusers” (see Figure A below). In addition, “Air is discharged unevenly like a seesaw” (see Figure B below). Why does this phenomenon occur?

In the figure on the left, six air diffusers are installed. The vertical air pipe is connected to the center of the horizontal pipe. Excessive air is blown from the air diffusers (Nos. 2, 3, 4, 5) nearest to the riser pipe. Hence, air diffusers No. 1 and No. 6 (farthest along the horizontal pipe) do not receive sufficient air. The figure on the right is essentially the same. Seven air diffusers are installed, but the volume of discharged air decreases as the distance from the vertical pipe increases.

Low air discharge resistance increases the risk of uneven air discharge

Air diffusers with one large air discharge opening have very low air discharge resistance. For example, the OHR AERATOR has the smallest air discharge resistance in the world at only 20–30 mmAq (=resistance at a depth of 2–3 cm in water). Low air discharge resistance helps air blower performance. This means a lot of air can be discharged with little power. But there is a high risk of air discharging unevenly when more than two units are installed. If this phenomenon occurs, you will need to carry out extensive pipe reconfiguration. Why is there a high risk that air will discharge unevenly? Please look at this figure:

The reason air is discharged unevenly

Porous air diffusers can discharge air evenly with a simple piping configuration

The piping configuration for porous air diffusers is straightforward. However, the piping configuration for air diffusers with one large air discharge opening is very difficult and requires complex calculations.
Porous air diffusers discharge air through small perforated pores, which have high airflow resistance of about 500 mmAq (=resistance at a depth of 50 cm in water) when brand new. It is difficult for air to discharge, so the whole air pipe first fills up with water. After enough the air pressure has built up, air discharges from all porous air diffusers simultaneously and evenly even if little heed has been paid to the piping configuration.
N.B. Porous air diffusers inevitably clog, further increasing the airflow resistance and decreasing the volume of air discharged. This leads to insufficient oxygen in the aeration tank. This is a serious problem.

OHR designs an appropriate air piping configuration calculated according
to your circumstances and fully guarantees even air discharge

The air piping configuration for an air diffuser with a large-diameter air discharge opening (such as the OHR AERATOR) is much more difficult than conventional porous air diffusers with large air discharge resistance. Calculations based on your circumstances are essential for even air discharge.
OHR calculates the correct piping configuration for your particular case and fully guarantees that air is discharged evenly, even when the installed OHR AERATORs number in the hundreds. In other words, accurate calculations are essential for even air discharge when using the OHR AERATOR.