Humboldt HM-4502 Double-Ring Infiltrometer - Manual (Page 3)

water fill valve that is connected to a water tank. Water enters the tank
and when filled, will eit the vent valve. At this time, close the water fill
valve. Next, close the vent valve. This seals the top of the water column.
When the ring water fill valve is opened to the ring, a vacuum forms at
the top of the water column. The constant head is maintained by a vent
tube that starts at the top vent and ends at the 0 mark on the Marriotte
Tube. Open the ring water flow valve and allow the water levels in the
double rings to stabilize and maintain a constant head. This should occur
when the water levels in the sight tubes begin to drop.
NOTE: Leaving the fill vent valve open will cahnge the tuve into a falling
head manometer.
Test
Please refer to ASTM D-3385 for details on how to perform the test. ASTM
documents are available for sale directly from the ASTM website:
http://www.astm.org/Standard/index.shtml
Double Ring Infiltrometer with Marriotte Tubes