DESIGN AND CONSTRUCTION
The Micro DVP uses coaxial Teflon tubing in lengths of 50’, 100’, 150’ and 200’ (15 m, 30 m, 50 m and 60 m). The 50 ft. (15 m) pump is also available with LDPE outer drive tube and a Teflon inner tube. The pump body and filter is 6” x 3/8” (150 x 10 mm). It is constructed of coaxial Teflon tubing with stainless steel fittings and a 100 mesh stainless steel filter. Filters are easily cleaned and replaced. A manifold at the top end of the pump has a 3/16” (5 mm) Teflon sample tube and a quick-connect fitting for easy attachment to the Control Unit. A multi-purge sampling head is also available for use with the CMT System.
OPERATIONFormation water enters through the filter under hydrostatic pressure into both the inner Teflon tube and the annulus of the coaxial tubes. Drive gas/air is cycled down the annular space between the two tubes to close the lower check valve and push the water up the inner sample tube. The pump is then vented to allow new formation water to enter both tubes under hydrostatic pressure. Air/gas pressures are carefully controlled at all times to ensure that the air/water interface never enters the body of the pump. Repeating the pressure/vent cycle brings the high quality sample to the surface at a controlled rate. The Micro DVP operates with 2 ft (0.6 m) or more head of water above the intake.
- Groundwater sampling in:
- CMT and Waterloo Multilevel Systems
- Low flow monitoring in narrow diameters