Bladder Pump Operation
When an Integra Bladder Pump is lowered into a well, hydraulic pressure allows formation water to enter the central Teflon chamber (the bladder) through the inlet filter.
Check valves ensure that no water flows back down through the pump or into the formation.
When compressed air or gas is vented (released), more formation water enters the bladder. When the pressure is reapplied, the fresh formation water is pushed up towards the surface.
The pressure/vent cycles are repeated, providing a steady flow of water up the sample line, without any stripping of volatiles from the sample. Turbidity is minimized due to the low flow rates and the gentle pumping action.
Thus a high quality VOC groundwater sample is obtained. |
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Higher Flow Rates
When larger purge volumes are required, Solinst Integra Bladder Pumps can deliver flow rates up to 2 L/min.
Alternatively a simple conversion kit can be used to quickly turn a stainless steel Integra Bladder Pump into a Solinst Double Valve Pump (DVP). These pneumatic drive DVPs can provide higher flow rates and sample from greater depths than most bladder pumps.
Flow rates vary with depth of pump below surface, depth below water level, size of drive and sample tubing, drive and vent cycle times, gas pressure applied and aquifer recharge.
Flow rates of the Integra Bladder Pump and the DVP compare favourably with published data for similar types and sizes of pumps, under similar conditions. For example:
1.66" x 2 ft (42 mm x 610 mm) Bladder Pump at 100 psi, with 1/4" OD drive line and 3/8" OD sample line; 50 ft (15 m) below grade with 25 ft (7.5 m) below water level gives 2 L/min. |
