Principle of Air-Lift Pump

Principle of air-lift pump (mammoth pump)

air mixture of sludge and air bubbles

sludge H M MIX MIX waste water p H STAT WW  WW  p MIX STAT air sludge  SL

Pressures on the tube inlet must be the same (outside - WW, inside - mixture): p p STAT  H *   H *   PLMIX  H´ * g WW WW MIX MIX g TRAN MIX

where HMIX = HTRANSPORT and pressure (head) loss pPLMIX can be

included in HTRANSPORT it is for ex. in H´TRANSPORT

For given HWW, WW, SLUDGE, H´TRAN and MMIX or MSLUDGE we can set MIX and

from it needed amount of air MAIR or VAIR (see example below).

3 3 Given data: MSLUDGE = 2000 kg/h, SLUDGE = 1200 kg/m , WW = 1000 kg/m ,

3 AIR = 1,2 kg/m , HWW = 3 m and H´TRAN = 6 m.

Calculation:

3 MIX = (HWW*WW) / (H´TRAN) = 3*1000 / 6 = 500 kg/m VSLUDGE = MSL / SL

MIX = (VSLUDGE*SLUDGE + VAIR*AIR) / (VSLUDGE + VAIR) VSLUDGE =2000/1200

3 MIX = (2000 + VAIR*1,2) / (1,67 + VAIR) = 500 VSLUDGE = 1,67 m /h

3 From the equation we can set: VAIR = 2,34 m /h or MAIR = 2,81 kg/h.

Tube diameter (mixture speed) depends on settling velocity of sludge or sand particles.

06ea0be451fb3b5052caf184c82ec757.doc P.Hoffman 04.04.po Kr.2018