Bottom Withdrawel Tube

The Bottom Withdrawal Tube method of determining particle size distribution is based on application of the Stokes Law using the Oden curve. The Bottom Withdrawal Tube consists of a transparent tube of large diameter which is open at one end and contracted at the other to a short section of small tube, on which is slipped a short piece of rubber tube which can be opened or closed with a pinch-clamp. The tube which is shown is 48 inches (1.22 meters) long with a 1" inside diameter, large enough to hold a pint (0.5 liter) sample. It is drawn down at the lower end to 1/4 inch (6.4 cm) inside diameter on which is slipped a 2" (5 cm) length of rubber tube closed by a pinch-clamp.