Fluid Dynamics Automatic Syphons

As many engineering studies and extensive field tests indicate, continuous discharge from the septic tank should be avoided. Continuous discharge causes the distribution to be limited to a few areas within the absorption field resulting in an overloading of the infiltrative surface in these areas. In order to maintain the infiltrative capacity of the soil, alternate periods of loading and resting of the leaching system should be provided. An inexpensive and trouble – free method of acheiving this solution is by using a dosing tank together with an Automatic Dosing Siphon.

What the Siphon Does

The automatic siphon system stores liquid in a tank until a certain elevation of the liquid is reached (the high water line), then the siphon automatically comes into operation and rapidly drains the tank to the low water line.

When the low water line is reached, the siphon shuts off and stops the flow of liquid. All liquid coming into the tank will again be stored until the high water line is reached and the siphon repeats the cycle. This is accomplished with no moving parts. The siphon operates on the hydraulic forces of the liquid rising in the dosing tank.



The primary use of the Automatic Siphon is to dose leach fields, sand filters, low pressure and other soil absorption systems. They may also be used to maintain minimum water velocities to insure proper scouring action of the liquid in the pipe lines. Alternating siphons are frequently used to direct effluent flow to different locations.


MODEL NUMBER Dim 207 313 413 417 423 430 523 630 836 1248
Draw Down A 7 13 13 17 23 30 23 30 36 48
Siphon Diameter B 2 3 4 4 4 4 5 6 8 12
Low Water to Discharge C 5.4 7.5 8 8 8 8 10.8 14 11.5 17
Trap Depth D 6.4 11.5 12 15 15 17 20 30 30 48.5
Average Discharge Rate G.P.M. 30 72 140 150 160 170 325 450 900 2000