5/2 x 12 DIFFUSER

 
2? x 12 DIFFUSER OPERATION
1. Install and submerge diffuser. Diffuser should be parallel to the water surface for best efficiency.
2. On startup, if the diffuser is dry, allow 30 minutes for the surface to wet.
3. The diffuser consists of a diffusing membrane laminated to a support base. The membrane
permits gas flow but resists water flow. Water that has condensed in the gas line can block the
flow of gas through the pores of the membrane. Sometimes, because of impatience with the
delay in obtaining the desired gas flow, there is a risk of increasing the gas pressure to
damaging levels. Excessive pressure can cause membrane delamination. Water should be
drained from the gas line, and on startup sufficient time must be allowed for the gas to force out
any water in the membrane pores. The 2? x 12 diffuser does not have a check valve as does
the 12x12s diffuser and therefore when the gas supply is off and the diffuser is submerged the
supply line may fill with water. If this occurs, slowly bring pressure up to 2 psi (55.5 Inches WC)
DWP and allow gas to be emitted from surface then slowly bring pressure to 4 psi (111.0 Inches
WC) DWP. DWP is defined below. Maintain this pressure until flow is established at 50% above
desired flow then reduce pressure / flow to desired level. It may take several hours to establish
the 150% flow rate.
4. CAUTION: NEVER EXCEED 4 PSI (111 INCHES OF WATER) DIFFUSER SURFACE
PRESSURE DROP (DWP).
5. Adjust flow as required to between 0 and 6.35 SCFH or 3.0 LPM. Recommended flow is much
less than 4 SCFH or 2.0 L/Min. The bubble quality will continue to get better as the material
thoroughly wets. The best bubble quality will be observed about 24 hours after wetting surface
and establishing a consistent flow rate. *See notes below regarding flow rates.
Diffuser surface pressure drop is also known as Dynamic Wet Pressure (DWP)
DWP = SP - dPsub - dPline
Where;
SP = Air or oxygen supply pressure in inches of water (psi x 27.68 = inches H2O).
dPsub = Diffuser water depth in inches (top of diffuser to water surface).
dPline = Pressure drop between pressure gauge and diffuser due to pipe line frictional loss
in inches of water in most cases 0 may be used. (the larger the ID of the supply
tubing and the lower the flow rate the less this number will be).
Max SP = DWP + dPsub + dPline
For example: If the diffuser is 50 inches below the water surface and the pressure drop in the line is 0
inches, then the gas supply pressure should never exceed
161 In. WC. = 111 In. WC. (from line 6 above)