Available Technology

BaroBall: Control Valve with Volume Flow Measurement

Barometric pumping is a remediation technique that removes volatile contaminants from soil in the vadose zone, above the water table. The BaroBall control valve increases the efficiency of barometric pumping and allows natural soil gas to flow out of an underground well, while restricting air flow from the surface int the well. air flowing into the well from the surface will dilute and possible spread still present in the subsurface.
Patent Abstract: 
The BaroBall control valve uses a ping-pong ball to provide low cracking pressure for outflow and to seal the well during inflow. When atmospheric pressure is higher than the pressures in the well (flow into the well), the ball is forced down and seals against the valve seat, thus closing the valve. When the pressure in the well is greater than the surface pressure, the ball rises on the stream of air and allows airflow. The pressure required to open the valve (cracking pressureO is related to the weight of the ball and is approximately 1mbar. The valve is a simple, inexpensive mechanical device requireing minimal maintenance. In-line condenser between the well and valve prevents moisture condensation in the valve that could cause the valve to freeze into one position during cold weather. The condenser holds the condensed water that is produced when warmer, moist air from the subsurface is cooled in the valve tubing during cold weather. The condensate can be drained periodically with a valve in the bottome of the condenser. A feature has been added to incorporate the ability to measure the volume of air passing through the valve without hindering its operation. The new design consists of a tapered column that permits the ping-pong ball to rise in the column in proportion to the flow rate. By periodically recording these flows along with vapor concentrations, the overall performance of the passive remediation system can be evaluated.
low-cost alternative treatment technique -simple design -easy to install -easy to maintain (P)
Internal Laboratory Ref #: 
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